Remove bcopy(), bzero(), bcmp()

[mirror_zfs.git] / lib / libzfs / libzfs_sendrecv.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2011, 2020 by Delphix. All rights reserved.
 * Copyright (c) 2012, Joyent, Inc. All rights reserved.
 * Copyright (c) 2012 Pawel Jakub Dawidek <pawel@dawidek.net>.
 * All rights reserved
 * Copyright (c) 2013 Steven Hartland. All rights reserved.
 * Copyright 2015, OmniTI Computer Consulting, Inc. All rights reserved.
 * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
 * Copyright (c) 2018, loli10K <ezomori.nozomu@gmail.com>. All rights reserved.
 * Copyright (c) 2019 Datto Inc.
 */

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <libintl.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <stddef.h>
#include <fcntl.h>
#include <sys/mount.h>
#include <sys/mntent.h>
#include <sys/mnttab.h>
#include <sys/avl.h>
#include <sys/debug.h>
#include <sys/stat.h>
#include <pthread.h>
#include <umem.h>
#include <time.h>

#include <libzfs.h>
#include <libzfs_core.h>
#include <libzutil.h>

#include "zfs_namecheck.h"
#include "zfs_prop.h"
#include "zfs_fletcher.h"
#include "libzfs_impl.h"
#include <cityhash.h>
#include <zlib.h>
#include <sys/zio_checksum.h>
#include <sys/dsl_crypt.h>
#include <sys/ddt.h>
#include <sys/socket.h>
#include <sys/sha2.h>

static int zfs_receive_impl(libzfs_handle_t *, const char *, const char *,
    recvflags_t *, int, const char *, nvlist_t *, avl_tree_t *, char **,
    const char *, nvlist_t *);
static int guid_to_name_redact_snaps(libzfs_handle_t *hdl, const char *parent,
    uint64_t guid, boolean_t bookmark_ok, uint64_t *redact_snap_guids,
    uint64_t num_redact_snaps, char *name);
static int guid_to_name(libzfs_handle_t *, const char *,
    uint64_t, boolean_t, char *);

typedef struct progress_arg {
        zfs_handle_t *pa_zhp;
        int pa_fd;
        boolean_t pa_parsable;
        boolean_t pa_estimate;
        int pa_verbosity;
} progress_arg_t;

static int
dump_record(dmu_replay_record_t *drr, void *payload, size_t payload_len,
    zio_cksum_t *zc, int outfd)
{
        ASSERT3U(offsetof(dmu_replay_record_t, drr_u.drr_checksum.drr_checksum),
            ==, sizeof (dmu_replay_record_t) - sizeof (zio_cksum_t));
        fletcher_4_incremental_native(drr,
            offsetof(dmu_replay_record_t, drr_u.drr_checksum.drr_checksum), zc);
        if (drr->drr_type != DRR_BEGIN) {
                ASSERT(ZIO_CHECKSUM_IS_ZERO(&drr->drr_u.
                    drr_checksum.drr_checksum));
                drr->drr_u.drr_checksum.drr_checksum = *zc;
        }
        fletcher_4_incremental_native(&drr->drr_u.drr_checksum.drr_checksum,
            sizeof (zio_cksum_t), zc);
        if (write(outfd, drr, sizeof (*drr)) == -1)
                return (errno);
        if (payload_len != 0) {
                fletcher_4_incremental_native(payload, payload_len, zc);
                if (write(outfd, payload, payload_len) == -1)
                        return (errno);
        }
        return (0);
}

/*
 * Routines for dealing with the AVL tree of fs-nvlists
 */
typedef struct fsavl_node {
        avl_node_t fn_node;
        nvlist_t *fn_nvfs;
        char *fn_snapname;
        uint64_t fn_guid;
} fsavl_node_t;

static int
fsavl_compare(const void *arg1, const void *arg2)
{
        const fsavl_node_t *fn1 = (const fsavl_node_t *)arg1;
        const fsavl_node_t *fn2 = (const fsavl_node_t *)arg2;

        return (TREE_CMP(fn1->fn_guid, fn2->fn_guid));
}

/*
 * Given the GUID of a snapshot, find its containing filesystem and
 * (optionally) name.
 */
static nvlist_t *
fsavl_find(avl_tree_t *avl, uint64_t snapguid, char **snapname)
{
        fsavl_node_t fn_find;
        fsavl_node_t *fn;

        fn_find.fn_guid = snapguid;

        fn = avl_find(avl, &fn_find, NULL);
        if (fn) {
                if (snapname)
                        *snapname = fn->fn_snapname;
                return (fn->fn_nvfs);
        }
        return (NULL);
}

static void
fsavl_destroy(avl_tree_t *avl)
{
        fsavl_node_t *fn;
        void *cookie;

        if (avl == NULL)
                return;

        cookie = NULL;
        while ((fn = avl_destroy_nodes(avl, &cookie)) != NULL)
                free(fn);
        avl_destroy(avl);
        free(avl);
}

/*
 * Given an nvlist, produce an avl tree of snapshots, ordered by guid
 */
static avl_tree_t *
fsavl_create(nvlist_t *fss)
{
        avl_tree_t *fsavl;
        nvpair_t *fselem = NULL;

        if ((fsavl = malloc(sizeof (avl_tree_t))) == NULL)
                return (NULL);

        avl_create(fsavl, fsavl_compare, sizeof (fsavl_node_t),
            offsetof(fsavl_node_t, fn_node));

        while ((fselem = nvlist_next_nvpair(fss, fselem)) != NULL) {
                nvlist_t *nvfs, *snaps;
                nvpair_t *snapelem = NULL;

                nvfs = fnvpair_value_nvlist(fselem);
                snaps = fnvlist_lookup_nvlist(nvfs, "snaps");

                while ((snapelem =
                    nvlist_next_nvpair(snaps, snapelem)) != NULL) {
                        fsavl_node_t *fn;

                        if ((fn = malloc(sizeof (fsavl_node_t))) == NULL) {
                                fsavl_destroy(fsavl);
                                return (NULL);
                        }
                        fn->fn_nvfs = nvfs;
                        fn->fn_snapname = nvpair_name(snapelem);
                        fn->fn_guid = fnvpair_value_uint64(snapelem);

                        /*
                         * Note: if there are multiple snaps with the
                         * same GUID, we ignore all but one.
                         */
                        avl_index_t where = 0;
                        if (avl_find(fsavl, fn, &where) == NULL)
                                avl_insert(fsavl, fn, where);
                        else
                                free(fn);
                }
        }

        return (fsavl);
}

/*
 * Routines for dealing with the giant nvlist of fs-nvlists, etc.
 */
typedef struct send_data {
        /*
         * assigned inside every recursive call,
         * restored from *_save on return:
         *
         * guid of fromsnap snapshot in parent dataset
         * txg of fromsnap snapshot in current dataset
         * txg of tosnap snapshot in current dataset
         */

        uint64_t parent_fromsnap_guid;
        uint64_t fromsnap_txg;
        uint64_t tosnap_txg;

        /* the nvlists get accumulated during depth-first traversal */
        nvlist_t *parent_snaps;
        nvlist_t *fss;
        nvlist_t *snapprops;
        nvlist_t *snapholds;    /* user holds */

        /* send-receive configuration, does not change during traversal */
        const char *fsname;
        const char *fromsnap;
        const char *tosnap;
        boolean_t recursive;
        boolean_t raw;
        boolean_t doall;
        boolean_t replicate;
        boolean_t skipmissing;
        boolean_t verbose;
        boolean_t backup;
        boolean_t seenfrom;
        boolean_t seento;
        boolean_t holds;        /* were holds requested with send -h */
        boolean_t props;

        /*
         * The header nvlist is of the following format:
         * {
         *   "tosnap" -> string
         *   "fromsnap" -> string (if incremental)
         *   "fss" -> {
         *      id -> {
         *
         *       "name" -> string (full name; for debugging)
         *       "parentfromsnap" -> number (guid of fromsnap in parent)
         *
         *       "props" -> { name -> value (only if set here) }
         *       "snaps" -> { name (lastname) -> number (guid) }
         *       "snapprops" -> { name (lastname) -> { name -> value } }
         *       "snapholds" -> { name (lastname) -> { holdname -> crtime } }
         *
         *       "origin" -> number (guid) (if clone)
         *       "is_encroot" -> boolean
         *       "sent" -> boolean (not on-disk)
         *      }
         *   }
         * }
         *
         */
} send_data_t;

static void
send_iterate_prop(zfs_handle_t *zhp, boolean_t received_only, nvlist_t *nv);

/*
 * Collect guid, valid props, optionally holds, etc. of a snapshot.
 * This interface is intended for use as a zfs_iter_snapshots_sorted visitor.
 */
static int
send_iterate_snap(zfs_handle_t *zhp, void *arg)
{
        send_data_t *sd = arg;
        uint64_t guid = zhp->zfs_dmustats.dds_guid;
        uint64_t txg = zhp->zfs_dmustats.dds_creation_txg;
        boolean_t isfromsnap, istosnap, istosnapwithnofrom;
        char *snapname;
        const char *from = sd->fromsnap;
        const char *to = sd->tosnap;

        snapname = strrchr(zhp->zfs_name, '@');
        assert(snapname != NULL);
        ++snapname;

        isfromsnap = (from != NULL && strcmp(from, snapname) == 0);
        istosnap = (to != NULL && strcmp(to, snapname) == 0);
        istosnapwithnofrom = (istosnap && from == NULL);

        if (sd->tosnap_txg != 0 && txg > sd->tosnap_txg) {
                if (sd->verbose) {
                        (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "skipping snapshot %s because it was created "
                            "after the destination snapshot (%s)\n"),
                            zhp->zfs_name, to);
                }
                zfs_close(zhp);
                return (0);
        }

        fnvlist_add_uint64(sd->parent_snaps, snapname, guid);

        /*
         * NB: if there is no fromsnap here (it's a newly created fs in
         * an incremental replication), we will substitute the tosnap.
         */
        if (isfromsnap || (sd->parent_fromsnap_guid == 0 && istosnap))
                sd->parent_fromsnap_guid = guid;

        if (!sd->recursive) {
                /*
                 * To allow a doall stream to work properly
                 * with a NULL fromsnap
                 */
                if (sd->doall && from == NULL && !sd->seenfrom)
                        sd->seenfrom = B_TRUE;

                if (!sd->seenfrom && isfromsnap) {
                        sd->seenfrom = B_TRUE;
                        zfs_close(zhp);
                        return (0);
                }

                if ((sd->seento || !sd->seenfrom) && !istosnapwithnofrom) {
                        zfs_close(zhp);
                        return (0);
                }

                if (istosnap)
                        sd->seento = B_TRUE;
        }

        nvlist_t *nv = fnvlist_alloc();
        send_iterate_prop(zhp, sd->backup, nv);
        fnvlist_add_nvlist(sd->snapprops, snapname, nv);
        fnvlist_free(nv);

        if (sd->holds) {
                nvlist_t *holds;
                if (lzc_get_holds(zhp->zfs_name, &holds) == 0) {
                        fnvlist_add_nvlist(sd->snapholds, snapname, holds);
                        fnvlist_free(holds);
                }
        }

        zfs_close(zhp);
        return (0);
}

/*
 * Collect all valid props from the handle snap into an nvlist.
 */
static void
send_iterate_prop(zfs_handle_t *zhp, boolean_t received_only, nvlist_t *nv)
{
        nvlist_t *props;

        if (received_only)
                props = zfs_get_recvd_props(zhp);
        else
                props = zhp->zfs_props;

        nvpair_t *elem = NULL;
        while ((elem = nvlist_next_nvpair(props, elem)) != NULL) {
                char *propname = nvpair_name(elem);
                zfs_prop_t prop = zfs_name_to_prop(propname);

                if (!zfs_prop_user(propname)) {
                        /*
                         * Realistically, this should never happen.  However,
                         * we want the ability to add DSL properties without
                         * needing to make incompatible version changes.  We
                         * need to ignore unknown properties to allow older
                         * software to still send datasets containing these
                         * properties, with the unknown properties elided.
                         */
                        if (prop == ZPROP_INVAL)
                                continue;

                        if (zfs_prop_readonly(prop))
                                continue;
                }

                nvlist_t *propnv = fnvpair_value_nvlist(elem);

                boolean_t isspacelimit = (prop == ZFS_PROP_QUOTA ||
                    prop == ZFS_PROP_RESERVATION ||
                    prop == ZFS_PROP_REFQUOTA ||
                    prop == ZFS_PROP_REFRESERVATION);
                if (isspacelimit && zhp->zfs_type == ZFS_TYPE_SNAPSHOT)
                        continue;

                char *source;
                if (nvlist_lookup_string(propnv, ZPROP_SOURCE, &source) == 0) {
                        if (strcmp(source, zhp->zfs_name) != 0 &&
                            strcmp(source, ZPROP_SOURCE_VAL_RECVD) != 0)
                                continue;
                } else {
                        /*
                         * May have no source before SPA_VERSION_RECVD_PROPS,
                         * but is still modifiable.
                         */
                        if (!isspacelimit)
                                continue;
                }

                if (zfs_prop_user(propname) ||
                    zfs_prop_get_type(prop) == PROP_TYPE_STRING) {
                        char *value;
                        value = fnvlist_lookup_string(propnv, ZPROP_VALUE);
                        fnvlist_add_string(nv, propname, value);
                } else {
                        uint64_t value;
                        value = fnvlist_lookup_uint64(propnv, ZPROP_VALUE);
                        fnvlist_add_uint64(nv, propname, value);
                }
        }
}

/*
 * returns snapshot creation txg
 * and returns 0 if the snapshot does not exist
 */
static uint64_t
get_snap_txg(libzfs_handle_t *hdl, const char *fs, const char *snap)
{
        char name[ZFS_MAX_DATASET_NAME_LEN];
        uint64_t txg = 0;

        if (fs == NULL || fs[0] == '\0' || snap == NULL || snap[0] == '\0')
                return (txg);

        (void) snprintf(name, sizeof (name), "%s@%s", fs, snap);
        if (zfs_dataset_exists(hdl, name, ZFS_TYPE_SNAPSHOT)) {
                zfs_handle_t *zhp = zfs_open(hdl, name, ZFS_TYPE_SNAPSHOT);
                if (zhp != NULL) {
                        txg = zfs_prop_get_int(zhp, ZFS_PROP_CREATETXG);
                        zfs_close(zhp);
                }
        }

        return (txg);
}

/*
 * Recursively generate nvlists describing datasets.  See comment
 * for the data structure send_data_t above for description of contents
 * of the nvlist.
 */
static int
send_iterate_fs(zfs_handle_t *zhp, void *arg)
{
        send_data_t *sd = arg;
        nvlist_t *nvfs = NULL, *nv = NULL;
        int rv = 0;
        uint64_t min_txg = 0, max_txg = 0;
        uint64_t txg = zhp->zfs_dmustats.dds_creation_txg;
        uint64_t guid = zhp->zfs_dmustats.dds_guid;
        uint64_t fromsnap_txg, tosnap_txg;
        char guidstring[64];

        /* These fields are restored on return from a recursive call. */
        uint64_t parent_fromsnap_guid_save = sd->parent_fromsnap_guid;
        uint64_t fromsnap_txg_save = sd->fromsnap_txg;
        uint64_t tosnap_txg_save = sd->tosnap_txg;

        fromsnap_txg = get_snap_txg(zhp->zfs_hdl, zhp->zfs_name, sd->fromsnap);
        if (fromsnap_txg != 0)
                sd->fromsnap_txg = fromsnap_txg;

        tosnap_txg = get_snap_txg(zhp->zfs_hdl, zhp->zfs_name, sd->tosnap);
        if (tosnap_txg != 0)
                sd->tosnap_txg = tosnap_txg;

        /*
         * On the send side, if the current dataset does not have tosnap,
         * perform two additional checks:
         *
         * - Skip sending the current dataset if it was created later than
         *   the parent tosnap.
         * - Return error if the current dataset was created earlier than
         *   the parent tosnap, unless --skip-missing specified. Then
         *   just print a warning.
         */
        if (sd->tosnap != NULL && tosnap_txg == 0) {
                if (sd->tosnap_txg != 0 && txg > sd->tosnap_txg) {
                        if (sd->verbose) {
                                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                                    "skipping dataset %s: snapshot %s does "
                                    "not exist\n"), zhp->zfs_name, sd->tosnap);
                        }
                } else if (sd->skipmissing) {
                        (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "WARNING: skipping dataset %s and its children:"
                            " snapshot %s does not exist\n"),
                            zhp->zfs_name, sd->tosnap);
                } else {
                        (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "cannot send %s@%s%s: snapshot %s@%s does not "
                            "exist\n"), sd->fsname, sd->tosnap, sd->recursive ?
                            dgettext(TEXT_DOMAIN, " recursively") : "",
                            zhp->zfs_name, sd->tosnap);
                        rv = EZFS_NOENT;
                }
                goto out;
        }

        nvfs = fnvlist_alloc();
        fnvlist_add_string(nvfs, "name", zhp->zfs_name);
        fnvlist_add_uint64(nvfs, "parentfromsnap", sd->parent_fromsnap_guid);

        if (zhp->zfs_dmustats.dds_origin[0] != '\0') {
                zfs_handle_t *origin = zfs_open(zhp->zfs_hdl,
                    zhp->zfs_dmustats.dds_origin, ZFS_TYPE_SNAPSHOT);
                if (origin == NULL) {
                        rv = -1;
                        goto out;
                }
                fnvlist_add_uint64(nvfs, "origin",
                    origin->zfs_dmustats.dds_guid);
                zfs_close(origin);
        }

        /* Iterate over props. */
        if (sd->props || sd->backup || sd->recursive) {
                nv = fnvlist_alloc();
                send_iterate_prop(zhp, sd->backup, nv);
                fnvlist_add_nvlist(nvfs, "props", nv);
        }
        if (zfs_prop_get_int(zhp, ZFS_PROP_ENCRYPTION) != ZIO_CRYPT_OFF) {
                boolean_t encroot;

                /* Determine if this dataset is an encryption root. */
                if (zfs_crypto_get_encryption_root(zhp, &encroot, NULL) != 0) {
                        rv = -1;
                        goto out;
                }

                if (encroot)
                        fnvlist_add_boolean(nvfs, "is_encroot");

                /*
                 * Encrypted datasets can only be sent with properties if
                 * the raw flag is specified because the receive side doesn't
                 * currently have a mechanism for recursively asking the user
                 * for new encryption parameters.
                 */
                if (!sd->raw) {
                        (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "cannot send %s@%s: encrypted dataset %s may not "
                            "be sent with properties without the raw flag\n"),
                            sd->fsname, sd->tosnap, zhp->zfs_name);
                        rv = -1;
                        goto out;
                }

        }

        /*
         * Iterate over snaps, and set sd->parent_fromsnap_guid.
         *
         * If this is a "doall" send, a replicate send or we're just trying
         * to gather a list of previous snapshots, iterate through all the
         * snaps in the txg range. Otherwise just look at the one we're
         * interested in.
         */
        sd->parent_fromsnap_guid = 0;
        sd->parent_snaps = fnvlist_alloc();
        sd->snapprops = fnvlist_alloc();
        if (sd->holds)
                sd->snapholds = fnvlist_alloc();
        if (sd->doall || sd->replicate || sd->tosnap == NULL) {
                if (!sd->replicate && fromsnap_txg != 0)
                        min_txg = fromsnap_txg;
                if (!sd->replicate && tosnap_txg != 0)
                        max_txg = tosnap_txg;
                (void) zfs_iter_snapshots_sorted(zhp, send_iterate_snap, sd,
                    min_txg, max_txg);
        } else {
                char snapname[MAXPATHLEN];
                zfs_handle_t *snap;

                (void) snprintf(snapname, sizeof (snapname), "%s@%s",
                    zhp->zfs_name, sd->tosnap);
                if (sd->fromsnap != NULL)
                        sd->seenfrom = B_TRUE;
                snap = zfs_open(zhp->zfs_hdl, snapname, ZFS_TYPE_SNAPSHOT);
                if (snap != NULL)
                        (void) send_iterate_snap(snap, sd);
        }

        fnvlist_add_nvlist(nvfs, "snaps", sd->parent_snaps);
        fnvlist_free(sd->parent_snaps);
        fnvlist_add_nvlist(nvfs, "snapprops", sd->snapprops);
        fnvlist_free(sd->snapprops);
        if (sd->holds) {
                fnvlist_add_nvlist(nvfs, "snapholds", sd->snapholds);
                fnvlist_free(sd->snapholds);
        }

        /* Do not allow the size of the properties list to exceed the limit */
        if ((fnvlist_size(nvfs) + fnvlist_size(sd->fss)) >
            zhp->zfs_hdl->libzfs_max_nvlist) {
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "warning: cannot send %s@%s: the size of the list of "
                    "snapshots and properties is too large to be received "
                    "successfully.\n"
                    "Select a smaller number of snapshots to send.\n"),
                    zhp->zfs_name, sd->tosnap);
                rv = EZFS_NOSPC;
                goto out;
        }
        /* Add this fs to nvlist. */
        (void) snprintf(guidstring, sizeof (guidstring),
            "0x%llx", (longlong_t)guid);
        fnvlist_add_nvlist(sd->fss, guidstring, nvfs);

        /* Iterate over children. */
        if (sd->recursive)
                rv = zfs_iter_filesystems(zhp, send_iterate_fs, sd);

out:
        /* Restore saved fields. */
        sd->parent_fromsnap_guid = parent_fromsnap_guid_save;
        sd->fromsnap_txg = fromsnap_txg_save;
        sd->tosnap_txg = tosnap_txg_save;

        fnvlist_free(nv);
        fnvlist_free(nvfs);

        zfs_close(zhp);
        return (rv);
}

static int
gather_nvlist(libzfs_handle_t *hdl, const char *fsname, const char *fromsnap,
    const char *tosnap, boolean_t recursive, boolean_t raw, boolean_t doall,
    boolean_t replicate, boolean_t skipmissing, boolean_t verbose,
    boolean_t backup, boolean_t holds, boolean_t props, nvlist_t **nvlp,
    avl_tree_t **avlp)
{
        zfs_handle_t *zhp;
        send_data_t sd = { 0 };
        int error;

        zhp = zfs_open(hdl, fsname, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME);
        if (zhp == NULL)
                return (EZFS_BADTYPE);

        sd.fss = fnvlist_alloc();
        sd.fsname = fsname;
        sd.fromsnap = fromsnap;
        sd.tosnap = tosnap;
        sd.recursive = recursive;
        sd.raw = raw;
        sd.doall = doall;
        sd.replicate = replicate;
        sd.skipmissing = skipmissing;
        sd.verbose = verbose;
        sd.backup = backup;
        sd.holds = holds;
        sd.props = props;

        if ((error = send_iterate_fs(zhp, &sd)) != 0) {
                fnvlist_free(sd.fss);
                if (avlp != NULL)
                        *avlp = NULL;
                *nvlp = NULL;
                return (error);
        }

        if (avlp != NULL && (*avlp = fsavl_create(sd.fss)) == NULL) {
                fnvlist_free(sd.fss);
                *nvlp = NULL;
                return (EZFS_NOMEM);
        }

        *nvlp = sd.fss;
        return (0);
}

/*
 * Routines specific to "zfs send"
 */
typedef struct send_dump_data {
        /* these are all just the short snapname (the part after the @) */
        const char *fromsnap;
        const char *tosnap;
        char prevsnap[ZFS_MAX_DATASET_NAME_LEN];
        uint64_t prevsnap_obj;
        boolean_t seenfrom, seento, replicate, doall, fromorigin;
        boolean_t dryrun, parsable, progress, embed_data, std_out;
        boolean_t large_block, compress, raw, holds;
        int outfd;
        boolean_t err;
        nvlist_t *fss;
        nvlist_t *snapholds;
        avl_tree_t *fsavl;
        snapfilter_cb_t *filter_cb;
        void *filter_cb_arg;
        nvlist_t *debugnv;
        char holdtag[ZFS_MAX_DATASET_NAME_LEN];
        int cleanup_fd;
        int verbosity;
        uint64_t size;
} send_dump_data_t;

static int
zfs_send_space(zfs_handle_t *zhp, const char *snapname, const char *from,
    enum lzc_send_flags flags, uint64_t *spacep)
{
        assert(snapname != NULL);

        int error = lzc_send_space(snapname, from, flags, spacep);
        if (error == 0)
                return (0);

        char errbuf[1024];
        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "warning: cannot estimate space for '%s'"), snapname);

        libzfs_handle_t *hdl = zhp->zfs_hdl;
        switch (error) {
        case EXDEV:
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "not an earlier snapshot from the same fs"));
                return (zfs_error(hdl, EZFS_CROSSTARGET, errbuf));

        case ENOENT:
                if (zfs_dataset_exists(hdl, snapname,
                    ZFS_TYPE_SNAPSHOT)) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "incremental source (%s) does not exist"),
                            snapname);
                }
                return (zfs_error(hdl, EZFS_NOENT, errbuf));

        case EDQUOT:
        case EFBIG:
        case EIO:
        case ENOLINK:
        case ENOSPC:
        case ENOSTR:
        case ENXIO:
        case EPIPE:
        case ERANGE:
        case EFAULT:
        case EROFS:
        case EINVAL:
                zfs_error_aux(hdl, "%s", strerror(error));
                return (zfs_error(hdl, EZFS_BADBACKUP, errbuf));

        default:
                return (zfs_standard_error(hdl, error, errbuf));
        }
}

/*
 * Dumps a backup of the given snapshot (incremental from fromsnap if it's not
 * NULL) to the file descriptor specified by outfd.
 */
static int
dump_ioctl(zfs_handle_t *zhp, const char *fromsnap, uint64_t fromsnap_obj,
    boolean_t fromorigin, int outfd, enum lzc_send_flags flags,
    nvlist_t *debugnv)
{
        zfs_cmd_t zc = {"\0"};
        libzfs_handle_t *hdl = zhp->zfs_hdl;
        nvlist_t *thisdbg;

        assert(zhp->zfs_type == ZFS_TYPE_SNAPSHOT);
        assert(fromsnap_obj == 0 || !fromorigin);

        (void) strlcpy(zc.zc_name, zhp->zfs_name, sizeof (zc.zc_name));
        zc.zc_cookie = outfd;
        zc.zc_obj = fromorigin;
        zc.zc_sendobj = zfs_prop_get_int(zhp, ZFS_PROP_OBJSETID);
        zc.zc_fromobj = fromsnap_obj;
        zc.zc_flags = flags;

        if (debugnv != NULL) {
                thisdbg = fnvlist_alloc();
                if (fromsnap != NULL && fromsnap[0] != '\0')
                        fnvlist_add_string(thisdbg, "fromsnap", fromsnap);
        }

        if (zfs_ioctl(zhp->zfs_hdl, ZFS_IOC_SEND, &zc) != 0) {
                char errbuf[1024];
                int error = errno;

                (void) snprintf(errbuf, sizeof (errbuf), "%s '%s'",
                    dgettext(TEXT_DOMAIN, "warning: cannot send"),
                    zhp->zfs_name);

                if (debugnv != NULL) {
                        fnvlist_add_uint64(thisdbg, "error", error);
                        fnvlist_add_nvlist(debugnv, zhp->zfs_name, thisdbg);
                        fnvlist_free(thisdbg);
                }

                switch (error) {
                case EXDEV:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "not an earlier snapshot from the same fs"));
                        return (zfs_error(hdl, EZFS_CROSSTARGET, errbuf));

                case EACCES:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "source key must be loaded"));
                        return (zfs_error(hdl, EZFS_CRYPTOFAILED, errbuf));

                case ENOENT:
                        if (zfs_dataset_exists(hdl, zc.zc_name,
                            ZFS_TYPE_SNAPSHOT)) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "incremental source (@%s) does not exist"),
                                    zc.zc_value);
                        }
                        return (zfs_error(hdl, EZFS_NOENT, errbuf));

                case EDQUOT:
                case EFBIG:
                case EIO:
                case ENOLINK:
                case ENOSPC:
                case ENOSTR:
                case ENXIO:
                case EPIPE:
                case ERANGE:
                case EFAULT:
                case EROFS:
                case EINVAL:
                        zfs_error_aux(hdl, "%s", strerror(errno));
                        return (zfs_error(hdl, EZFS_BADBACKUP, errbuf));

                default:
                        return (zfs_standard_error(hdl, errno, errbuf));
                }
        }

        if (debugnv != NULL) {
                fnvlist_add_nvlist(debugnv, zhp->zfs_name, thisdbg);
                fnvlist_free(thisdbg);
        }

        return (0);
}

static void
gather_holds(zfs_handle_t *zhp, send_dump_data_t *sdd)
{
        assert(zhp->zfs_type == ZFS_TYPE_SNAPSHOT);

        /*
         * zfs_send() only sets snapholds for sends that need them,
         * e.g. replication and doall.
         */
        if (sdd->snapholds == NULL)
                return;

        fnvlist_add_string(sdd->snapholds, zhp->zfs_name, sdd->holdtag);
}

int
zfs_send_progress(zfs_handle_t *zhp, int fd, uint64_t *bytes_written,
    uint64_t *blocks_visited)
{
        zfs_cmd_t zc = {"\0"};

        if (bytes_written != NULL)
                *bytes_written = 0;
        if (blocks_visited != NULL)
                *blocks_visited = 0;
        (void) strlcpy(zc.zc_name, zhp->zfs_name, sizeof (zc.zc_name));
        zc.zc_cookie = fd;
        if (zfs_ioctl(zhp->zfs_hdl, ZFS_IOC_SEND_PROGRESS, &zc) != 0)
                return (errno);
        if (bytes_written != NULL)
                *bytes_written = zc.zc_cookie;
        if (blocks_visited != NULL)
                *blocks_visited = zc.zc_objset_type;
        return (0);
}

static void *
send_progress_thread(void *arg)
{
        progress_arg_t *pa = arg;
        zfs_handle_t *zhp = pa->pa_zhp;
        uint64_t bytes;
        uint64_t blocks;
        char buf[16];
        time_t t;
        struct tm *tm;
        int err;

        if (!pa->pa_parsable) {
                (void) fprintf(stderr,
                    "TIME       %s   %sSNAPSHOT %s\n",
                    pa->pa_estimate ? "BYTES" : " SENT",
                    pa->pa_verbosity >= 2 ? "   BLOCKS    " : "",
                    zhp->zfs_name);
        }

        /*
         * Print the progress from ZFS_IOC_SEND_PROGRESS every second.
         */
        for (;;) {
                (void) sleep(1);
                if ((err = zfs_send_progress(zhp, pa->pa_fd, &bytes,
                    &blocks)) != 0) {
                        if (err == EINTR || err == ENOENT)
                                return ((void *)0);
                        return ((void *)(uintptr_t)err);
                }

                (void) time(&t);
                tm = localtime(&t);

                if (pa->pa_verbosity >= 2 && pa->pa_parsable) {
                        (void) fprintf(stderr,
                            "%02d:%02d:%02d\t%llu\t%llu\t%s\n",
                            tm->tm_hour, tm->tm_min, tm->tm_sec,
                            (u_longlong_t)bytes, (u_longlong_t)blocks,
                            zhp->zfs_name);
                } else if (pa->pa_verbosity >= 2) {
                        zfs_nicenum(bytes, buf, sizeof (buf));
                        (void) fprintf(stderr,
                            "%02d:%02d:%02d   %5s    %8llu    %s\n",
                            tm->tm_hour, tm->tm_min, tm->tm_sec,
                            buf, (u_longlong_t)blocks, zhp->zfs_name);
                } else if (pa->pa_parsable) {
                        (void) fprintf(stderr, "%02d:%02d:%02d\t%llu\t%s\n",
                            tm->tm_hour, tm->tm_min, tm->tm_sec,
                            (u_longlong_t)bytes, zhp->zfs_name);
                } else {
                        zfs_nicebytes(bytes, buf, sizeof (buf));
                        (void) fprintf(stderr, "%02d:%02d:%02d   %5s   %s\n",
                            tm->tm_hour, tm->tm_min, tm->tm_sec,
                            buf, zhp->zfs_name);
                }
        }
}

static void
send_print_verbose(FILE *fout, const char *tosnap, const char *fromsnap,
    uint64_t size, boolean_t parsable)
{
        if (parsable) {
                if (fromsnap != NULL) {
                        (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                            "incremental\t%s\t%s"), fromsnap, tosnap);
                } else {
                        (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                            "full\t%s"), tosnap);
                }
                (void) fprintf(fout, "\t%llu", (longlong_t)size);
        } else {
                if (fromsnap != NULL) {
                        if (strchr(fromsnap, '@') == NULL &&
                            strchr(fromsnap, '#') == NULL) {
                                (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                                    "send from @%s to %s"), fromsnap, tosnap);
                        } else {
                                (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                                    "send from %s to %s"), fromsnap, tosnap);
                        }
                } else {
                        (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                            "full send of %s"), tosnap);
                }
                if (size != 0) {
                        char buf[16];
                        zfs_nicebytes(size, buf, sizeof (buf));
                        (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                            " estimated size is %s"), buf);
                }
        }
        (void) fprintf(fout, "\n");
}

/*
 * Send a single filesystem snapshot, updating the send dump data.
 * This interface is intended for use as a zfs_iter_snapshots_sorted visitor.
 */
static int
dump_snapshot(zfs_handle_t *zhp, void *arg)
{
        send_dump_data_t *sdd = arg;
        progress_arg_t pa = { 0 };
        pthread_t tid;
        char *thissnap;
        enum lzc_send_flags flags = 0;
        int err;
        boolean_t isfromsnap, istosnap, fromorigin;
        boolean_t exclude = B_FALSE;
        FILE *fout = sdd->std_out ? stdout : stderr;

        err = 0;
        thissnap = strchr(zhp->zfs_name, '@') + 1;
        isfromsnap = (sdd->fromsnap != NULL &&
            strcmp(sdd->fromsnap, thissnap) == 0);

        if (!sdd->seenfrom && isfromsnap) {
                gather_holds(zhp, sdd);
                sdd->seenfrom = B_TRUE;
                (void) strlcpy(sdd->prevsnap, thissnap, sizeof (sdd->prevsnap));
                sdd->prevsnap_obj = zfs_prop_get_int(zhp, ZFS_PROP_OBJSETID);
                zfs_close(zhp);
                return (0);
        }

        if (sdd->seento || !sdd->seenfrom) {
                zfs_close(zhp);
                return (0);
        }

        istosnap = (strcmp(sdd->tosnap, thissnap) == 0);
        if (istosnap)
                sdd->seento = B_TRUE;

        if (sdd->large_block)
                flags |= LZC_SEND_FLAG_LARGE_BLOCK;
        if (sdd->embed_data)
                flags |= LZC_SEND_FLAG_EMBED_DATA;
        if (sdd->compress)
                flags |= LZC_SEND_FLAG_COMPRESS;
        if (sdd->raw)
                flags |= LZC_SEND_FLAG_RAW;

        if (!sdd->doall && !isfromsnap && !istosnap) {
                if (sdd->replicate) {
                        char *snapname;
                        nvlist_t *snapprops;
                        /*
                         * Filter out all intermediate snapshots except origin
                         * snapshots needed to replicate clones.
                         */
                        nvlist_t *nvfs = fsavl_find(sdd->fsavl,
                            zhp->zfs_dmustats.dds_guid, &snapname);

                        if (nvfs != NULL) {
                                snapprops = fnvlist_lookup_nvlist(nvfs,
                                    "snapprops");
                                snapprops = fnvlist_lookup_nvlist(snapprops,
                                    thissnap);
                                exclude = !nvlist_exists(snapprops,
                                    "is_clone_origin");
                        }
                } else {
                        exclude = B_TRUE;
                }
        }

        /*
         * If a filter function exists, call it to determine whether
         * this snapshot will be sent.
         */
        if (exclude || (sdd->filter_cb != NULL &&
            sdd->filter_cb(zhp, sdd->filter_cb_arg) == B_FALSE)) {
                /*
                 * This snapshot is filtered out.  Don't send it, and don't
                 * set prevsnap_obj, so it will be as if this snapshot didn't
                 * exist, and the next accepted snapshot will be sent as
                 * an incremental from the last accepted one, or as the
                 * first (and full) snapshot in the case of a replication,
                 * non-incremental send.
                 */
                zfs_close(zhp);
                return (0);
        }

        gather_holds(zhp, sdd);
        fromorigin = sdd->prevsnap[0] == '\0' &&
            (sdd->fromorigin || sdd->replicate);

        if (sdd->verbosity != 0) {
                uint64_t size = 0;
                char fromds[ZFS_MAX_DATASET_NAME_LEN];

                if (sdd->prevsnap[0] != '\0') {
                        (void) strlcpy(fromds, zhp->zfs_name, sizeof (fromds));
                        *(strchr(fromds, '@') + 1) = '\0';
                        (void) strlcat(fromds, sdd->prevsnap, sizeof (fromds));
                }
                if (zfs_send_space(zhp, zhp->zfs_name,
                    sdd->prevsnap[0] ? fromds : NULL, flags, &size) == 0) {
                        send_print_verbose(fout, zhp->zfs_name,
                            sdd->prevsnap[0] ? sdd->prevsnap : NULL,
                            size, sdd->parsable);
                        sdd->size += size;
                }
        }

        if (!sdd->dryrun) {
                /*
                 * If progress reporting is requested, spawn a new thread to
                 * poll ZFS_IOC_SEND_PROGRESS at a regular interval.
                 */
                if (sdd->progress) {
                        pa.pa_zhp = zhp;
                        pa.pa_fd = sdd->outfd;
                        pa.pa_parsable = sdd->parsable;
                        pa.pa_estimate = B_FALSE;
                        pa.pa_verbosity = sdd->verbosity;

                        if ((err = pthread_create(&tid, NULL,
                            send_progress_thread, &pa)) != 0) {
                                zfs_close(zhp);
                                return (err);
                        }
                }

                err = dump_ioctl(zhp, sdd->prevsnap, sdd->prevsnap_obj,
                    fromorigin, sdd->outfd, flags, sdd->debugnv);

                if (sdd->progress) {
                        void *status = NULL;
                        (void) pthread_cancel(tid);
                        (void) pthread_join(tid, &status);
                        int error = (int)(uintptr_t)status;
                        if (error != 0 && status != PTHREAD_CANCELED) {
                                return (zfs_standard_error(zhp->zfs_hdl, error,
                                    dgettext(TEXT_DOMAIN,
                                    "progress thread exited nonzero")));
                        }
                }
        }

        (void) strcpy(sdd->prevsnap, thissnap);
        sdd->prevsnap_obj = zfs_prop_get_int(zhp, ZFS_PROP_OBJSETID);
        zfs_close(zhp);
        return (err);
}

/*
 * Send all snapshots for a filesystem, updating the send dump data.
 */
static int
dump_filesystem(zfs_handle_t *zhp, send_dump_data_t *sdd)
{
        int rv = 0;
        boolean_t missingfrom = B_FALSE;
        zfs_cmd_t zc = {"\0"};
        uint64_t min_txg = 0, max_txg = 0;

        /*
         * Make sure the tosnap exists.
         */
        (void) snprintf(zc.zc_name, sizeof (zc.zc_name), "%s@%s",
            zhp->zfs_name, sdd->tosnap);
        if (zfs_ioctl(zhp->zfs_hdl, ZFS_IOC_OBJSET_STATS, &zc) != 0) {
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "WARNING: could not send %s@%s: does not exist\n"),
                    zhp->zfs_name, sdd->tosnap);
                sdd->err = B_TRUE;
                return (0);
        }

        /*
         * If this fs does not have fromsnap, and we're doing
         * recursive, we need to send a full stream from the
         * beginning (or an incremental from the origin if this
         * is a clone).  If we're doing non-recursive, then let
         * them get the error.
         */
        if (sdd->replicate && sdd->fromsnap) {
                /*
                 * Make sure the fromsnap exists.
                 */
                (void) snprintf(zc.zc_name, sizeof (zc.zc_name), "%s@%s",
                    zhp->zfs_name, sdd->fromsnap);
                if (zfs_ioctl(zhp->zfs_hdl, ZFS_IOC_OBJSET_STATS, &zc) != 0)
                        missingfrom = B_TRUE;
        }

        sdd->seenfrom = sdd->seento = B_FALSE;
        sdd->prevsnap[0] = '\0';
        sdd->prevsnap_obj = 0;
        if (sdd->fromsnap == NULL || missingfrom)
                sdd->seenfrom = B_TRUE;

        /*
         * Iterate through all snapshots and process the ones we will be
         * sending. If we only have a "from" and "to" snapshot to deal
         * with, we can avoid iterating through all the other snapshots.
         */
        if (sdd->doall || sdd->replicate || sdd->tosnap == NULL) {
                if (!sdd->replicate) {
                        if (sdd->fromsnap != NULL) {
                                min_txg = get_snap_txg(zhp->zfs_hdl,
                                    zhp->zfs_name, sdd->fromsnap);
                        }
                        if (sdd->tosnap != NULL) {
                                max_txg = get_snap_txg(zhp->zfs_hdl,
                                    zhp->zfs_name, sdd->tosnap);
                        }
                }
                rv = zfs_iter_snapshots_sorted(zhp, dump_snapshot, sdd,
                    min_txg, max_txg);
        } else {
                char snapname[MAXPATHLEN] = { 0 };
                zfs_handle_t *snap;

                /* Dump fromsnap. */
                if (!sdd->seenfrom) {
                        (void) snprintf(snapname, sizeof (snapname),
                            "%s@%s", zhp->zfs_name, sdd->fromsnap);
                        snap = zfs_open(zhp->zfs_hdl, snapname,
                            ZFS_TYPE_SNAPSHOT);
                        if (snap != NULL)
                                rv = dump_snapshot(snap, sdd);
                        else
                                rv = -1;
                }

                /* Dump tosnap. */
                if (rv == 0) {
                        (void) snprintf(snapname, sizeof (snapname),
                            "%s@%s", zhp->zfs_name, sdd->tosnap);
                        snap = zfs_open(zhp->zfs_hdl, snapname,
                            ZFS_TYPE_SNAPSHOT);
                        if (snap != NULL)
                                rv = dump_snapshot(snap, sdd);
                        else
                                rv = -1;
                }
        }

        if (!sdd->seenfrom) {
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "WARNING: could not send %s@%s:\n"
                    "incremental source (%s@%s) does not exist\n"),
                    zhp->zfs_name, sdd->tosnap,
                    zhp->zfs_name, sdd->fromsnap);
                sdd->err = B_TRUE;
        } else if (!sdd->seento) {
                if (sdd->fromsnap) {
                        (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "WARNING: could not send %s@%s:\n"
                            "incremental source (%s@%s) "
                            "is not earlier than it\n"),
                            zhp->zfs_name, sdd->tosnap,
                            zhp->zfs_name, sdd->fromsnap);
                } else {
                        (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "WARNING: "
                            "could not send %s@%s: does not exist\n"),
                            zhp->zfs_name, sdd->tosnap);
                }
                sdd->err = B_TRUE;
        }

        return (rv);
}

/*
 * Send all snapshots for all filesystems in sdd.
 */
static int
dump_filesystems(zfs_handle_t *rzhp, send_dump_data_t *sdd)
{
        nvpair_t *fspair;
        boolean_t needagain, progress;

        if (!sdd->replicate)
                return (dump_filesystem(rzhp, sdd));

        /* Mark the clone origin snapshots. */
        for (fspair = nvlist_next_nvpair(sdd->fss, NULL); fspair;
            fspair = nvlist_next_nvpair(sdd->fss, fspair)) {
                nvlist_t *nvfs;
                uint64_t origin_guid = 0;

                nvfs = fnvpair_value_nvlist(fspair);
                (void) nvlist_lookup_uint64(nvfs, "origin", &origin_guid);
                if (origin_guid != 0) {
                        char *snapname;
                        nvlist_t *origin_nv = fsavl_find(sdd->fsavl,
                            origin_guid, &snapname);
                        if (origin_nv != NULL) {
                                nvlist_t *snapprops;
                                snapprops = fnvlist_lookup_nvlist(origin_nv,
                                    "snapprops");
                                snapprops = fnvlist_lookup_nvlist(snapprops,
                                    snapname);
                                fnvlist_add_boolean(snapprops,
                                    "is_clone_origin");
                        }
                }
        }
again:
        needagain = progress = B_FALSE;
        for (fspair = nvlist_next_nvpair(sdd->fss, NULL); fspair;
            fspair = nvlist_next_nvpair(sdd->fss, fspair)) {
                nvlist_t *fslist, *parent_nv;
                char *fsname;
                zfs_handle_t *zhp;
                int err;
                uint64_t origin_guid = 0;
                uint64_t parent_guid = 0;

                fslist = fnvpair_value_nvlist(fspair);
                if (nvlist_lookup_boolean(fslist, "sent") == 0)
                        continue;

                fsname = fnvlist_lookup_string(fslist, "name");
                (void) nvlist_lookup_uint64(fslist, "origin", &origin_guid);
                (void) nvlist_lookup_uint64(fslist, "parentfromsnap",
                    &parent_guid);

                if (parent_guid != 0) {
                        parent_nv = fsavl_find(sdd->fsavl, parent_guid, NULL);
                        if (!nvlist_exists(parent_nv, "sent")) {
                                /* Parent has not been sent; skip this one. */
                                needagain = B_TRUE;
                                continue;
                        }
                }

                if (origin_guid != 0) {
                        nvlist_t *origin_nv = fsavl_find(sdd->fsavl,
                            origin_guid, NULL);
                        if (origin_nv != NULL &&
                            !nvlist_exists(origin_nv, "sent")) {
                                /*
                                 * Origin has not been sent yet;
                                 * skip this clone.
                                 */
                                needagain = B_TRUE;
                                continue;
                        }
                }

                zhp = zfs_open(rzhp->zfs_hdl, fsname, ZFS_TYPE_DATASET);
                if (zhp == NULL)
                        return (-1);
                err = dump_filesystem(zhp, sdd);
                fnvlist_add_boolean(fslist, "sent");
                progress = B_TRUE;
                zfs_close(zhp);
                if (err)
                        return (err);
        }
        if (needagain) {
                assert(progress);
                goto again;
        }

        /* Clean out the sent flags in case we reuse this fss. */
        for (fspair = nvlist_next_nvpair(sdd->fss, NULL); fspair;
            fspair = nvlist_next_nvpair(sdd->fss, fspair)) {
                nvlist_t *fslist;

                fslist = fnvpair_value_nvlist(fspair);
                (void) nvlist_remove_all(fslist, "sent");
        }

        return (0);
}

nvlist_t *
zfs_send_resume_token_to_nvlist(libzfs_handle_t *hdl, const char *token)
{
        unsigned int version;
        int nread, i;
        unsigned long long checksum, packed_len;

        /*
         * Decode token header, which is:
         *   <token version>-<checksum of payload>-<uncompressed payload length>
         * Note that the only supported token version is 1.
         */
        nread = sscanf(token, "%u-%llx-%llx-",
            &version, &checksum, &packed_len);
        if (nread != 3) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "resume token is corrupt (invalid format)"));
                return (NULL);
        }

        if (version != ZFS_SEND_RESUME_TOKEN_VERSION) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "resume token is corrupt (invalid version %u)"),
                    version);
                return (NULL);
        }

        /* Convert hexadecimal representation to binary. */
        token = strrchr(token, '-') + 1;
        int len = strlen(token) / 2;
        unsigned char *compressed = zfs_alloc(hdl, len);
        for (i = 0; i < len; i++) {
                nread = sscanf(token + i * 2, "%2hhx", compressed + i);
                if (nread != 1) {
                        free(compressed);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "resume token is corrupt "
                            "(payload is not hex-encoded)"));
                        return (NULL);
                }
        }

        /* Verify checksum. */
        zio_cksum_t cksum;
        fletcher_4_native_varsize(compressed, len, &cksum);
        if (cksum.zc_word[0] != checksum) {
                free(compressed);
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "resume token is corrupt (incorrect checksum)"));
                return (NULL);
        }

        /* Uncompress. */
        void *packed = zfs_alloc(hdl, packed_len);
        uLongf packed_len_long = packed_len;
        if (uncompress(packed, &packed_len_long, compressed, len) != Z_OK ||
            packed_len_long != packed_len) {
                free(packed);
                free(compressed);
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "resume token is corrupt (decompression failed)"));
                return (NULL);
        }

        /* Unpack nvlist. */
        nvlist_t *nv;
        int error = nvlist_unpack(packed, packed_len, &nv, KM_SLEEP);
        free(packed);
        free(compressed);
        if (error != 0) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "resume token is corrupt (nvlist_unpack failed)"));
                return (NULL);
        }
        return (nv);
}

static enum lzc_send_flags
lzc_flags_from_sendflags(const sendflags_t *flags)
{
        enum lzc_send_flags lzc_flags = 0;

        if (flags->largeblock)
                lzc_flags |= LZC_SEND_FLAG_LARGE_BLOCK;
        if (flags->embed_data)
                lzc_flags |= LZC_SEND_FLAG_EMBED_DATA;
        if (flags->compress)
                lzc_flags |= LZC_SEND_FLAG_COMPRESS;
        if (flags->raw)
                lzc_flags |= LZC_SEND_FLAG_RAW;
        if (flags->saved)
                lzc_flags |= LZC_SEND_FLAG_SAVED;

        return (lzc_flags);
}

static int
estimate_size(zfs_handle_t *zhp, const char *from, int fd, sendflags_t *flags,
    uint64_t resumeobj, uint64_t resumeoff, uint64_t bytes,
    const char *redactbook, char *errbuf)
{
        uint64_t size;
        FILE *fout = flags->dryrun ? stdout : stderr;
        progress_arg_t pa = { 0 };
        int err = 0;
        pthread_t ptid;

        if (flags->progress) {
                pa.pa_zhp = zhp;
                pa.pa_fd = fd;
                pa.pa_parsable = flags->parsable;
                pa.pa_estimate = B_TRUE;
                pa.pa_verbosity = flags->verbosity;

                err = pthread_create(&ptid, NULL,
                    send_progress_thread, &pa);
                if (err != 0) {
                        zfs_error_aux(zhp->zfs_hdl, "%s", strerror(errno));
                        return (zfs_error(zhp->zfs_hdl,
                            EZFS_THREADCREATEFAILED, errbuf));
                }
        }

        err = lzc_send_space_resume_redacted(zhp->zfs_name, from,
            lzc_flags_from_sendflags(flags), resumeobj, resumeoff, bytes,
            redactbook, fd, &size);

        if (flags->progress) {
                void *status = NULL;
                (void) pthread_cancel(ptid);
                (void) pthread_join(ptid, &status);
                int error = (int)(uintptr_t)status;
                if (error != 0 && status != PTHREAD_CANCELED) {
                        char errbuf[1024];
                        (void) snprintf(errbuf, sizeof (errbuf),
                            dgettext(TEXT_DOMAIN, "progress thread exited "
                            "nonzero"));
                        return (zfs_standard_error(zhp->zfs_hdl, error,
                            errbuf));
                }
        }

        if (err != 0) {
                zfs_error_aux(zhp->zfs_hdl, "%s", strerror(err));
                return (zfs_error(zhp->zfs_hdl, EZFS_BADBACKUP,
                    errbuf));
        }
        send_print_verbose(fout, zhp->zfs_name, from, size,
            flags->parsable);

        if (flags->parsable) {
                (void) fprintf(fout, "size\t%llu\n", (longlong_t)size);
        } else {
                char buf[16];
                zfs_nicenum(size, buf, sizeof (buf));
                (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                    "total estimated size is %s\n"), buf);
        }
        return (0);
}

static boolean_t
redact_snaps_contains(const uint64_t *snaps, uint64_t num_snaps, uint64_t guid)
{
        for (int i = 0; i < num_snaps; i++) {
                if (snaps[i] == guid)
                        return (B_TRUE);
        }
        return (B_FALSE);
}

static boolean_t
redact_snaps_equal(const uint64_t *snaps1, uint64_t num_snaps1,
    const uint64_t *snaps2, uint64_t num_snaps2)
{
        if (num_snaps1 != num_snaps2)
                return (B_FALSE);
        for (int i = 0; i < num_snaps1; i++) {
                if (!redact_snaps_contains(snaps2, num_snaps2, snaps1[i]))
                        return (B_FALSE);
        }
        return (B_TRUE);
}

static int
get_bookmarks(const char *path, nvlist_t **bmarksp)
{
        nvlist_t *props = fnvlist_alloc();
        int error;

        fnvlist_add_boolean(props, "redact_complete");
        fnvlist_add_boolean(props, zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS));
        error = lzc_get_bookmarks(path, props, bmarksp);
        fnvlist_free(props);
        return (error);
}

static nvpair_t *
find_redact_pair(nvlist_t *bmarks, const uint64_t *redact_snap_guids,
    int num_redact_snaps)
{
        nvpair_t *pair;

        for (pair = nvlist_next_nvpair(bmarks, NULL); pair;
            pair = nvlist_next_nvpair(bmarks, pair)) {

                nvlist_t *bmark = fnvpair_value_nvlist(pair);
                nvlist_t *vallist = fnvlist_lookup_nvlist(bmark,
                    zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS));
                uint_t len = 0;
                uint64_t *bmarksnaps = fnvlist_lookup_uint64_array(vallist,
                    ZPROP_VALUE, &len);
                if (redact_snaps_equal(redact_snap_guids,
                    num_redact_snaps, bmarksnaps, len)) {
                        break;
                }
        }
        return (pair);
}

static boolean_t
get_redact_complete(nvpair_t *pair)
{
        nvlist_t *bmark = fnvpair_value_nvlist(pair);
        nvlist_t *vallist = fnvlist_lookup_nvlist(bmark, "redact_complete");
        boolean_t complete = fnvlist_lookup_boolean_value(vallist,
            ZPROP_VALUE);

        return (complete);
}

/*
 * Check that the list of redaction snapshots in the bookmark matches the send
 * we're resuming, and return whether or not it's complete.
 *
 * Note that the caller needs to free the contents of *bookname with free() if
 * this function returns successfully.
 */
static int
find_redact_book(libzfs_handle_t *hdl, const char *path,
    const uint64_t *redact_snap_guids, int num_redact_snaps,
    char **bookname)
{
        char errbuf[1024];
        nvlist_t *bmarks;

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot resume send"));

        int error = get_bookmarks(path, &bmarks);
        if (error != 0) {
                if (error == ESRCH) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "nonexistent redaction bookmark provided"));
                } else if (error == ENOENT) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "dataset to be sent no longer exists"));
                } else {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "unknown error: %s"), strerror(error));
                }
                return (zfs_error(hdl, EZFS_BADPROP, errbuf));
        }
        nvpair_t *pair = find_redact_pair(bmarks, redact_snap_guids,
            num_redact_snaps);
        if (pair == NULL)  {
                fnvlist_free(bmarks);
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "no appropriate redaction bookmark exists"));
                return (zfs_error(hdl, EZFS_BADPROP, errbuf));
        }
        boolean_t complete = get_redact_complete(pair);
        if (!complete) {
                fnvlist_free(bmarks);
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "incomplete redaction bookmark provided"));
                return (zfs_error(hdl, EZFS_BADPROP, errbuf));
        }
        *bookname = strndup(nvpair_name(pair), ZFS_MAX_DATASET_NAME_LEN);
        ASSERT3P(*bookname, !=, NULL);
        fnvlist_free(bmarks);
        return (0);
}

static enum lzc_send_flags
lzc_flags_from_resume_nvl(nvlist_t *resume_nvl)
{
        enum lzc_send_flags lzc_flags = 0;

        if (nvlist_exists(resume_nvl, "largeblockok"))
                lzc_flags |= LZC_SEND_FLAG_LARGE_BLOCK;
        if (nvlist_exists(resume_nvl, "embedok"))
                lzc_flags |= LZC_SEND_FLAG_EMBED_DATA;
        if (nvlist_exists(resume_nvl, "compressok"))
                lzc_flags |= LZC_SEND_FLAG_COMPRESS;
        if (nvlist_exists(resume_nvl, "rawok"))
                lzc_flags |= LZC_SEND_FLAG_RAW;
        if (nvlist_exists(resume_nvl, "savedok"))
                lzc_flags |= LZC_SEND_FLAG_SAVED;

        return (lzc_flags);
}

static int
zfs_send_resume_impl_cb_impl(libzfs_handle_t *hdl, sendflags_t *flags,
    int outfd, nvlist_t *resume_nvl)
{
        char errbuf[1024];
        char *toname;
        char *fromname = NULL;
        uint64_t resumeobj, resumeoff, toguid, fromguid, bytes;
        zfs_handle_t *zhp;
        int error = 0;
        char name[ZFS_MAX_DATASET_NAME_LEN];
        FILE *fout = (flags->verbosity > 0 && flags->dryrun) ? stdout : stderr;
        uint64_t *redact_snap_guids = NULL;
        int num_redact_snaps = 0;
        char *redact_book = NULL;

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot resume send"));

        if (flags->verbosity != 0) {
                (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                    "resume token contents:\n"));
                nvlist_print(fout, resume_nvl);
        }

        if (nvlist_lookup_string(resume_nvl, "toname", &toname) != 0 ||
            nvlist_lookup_uint64(resume_nvl, "object", &resumeobj) != 0 ||
            nvlist_lookup_uint64(resume_nvl, "offset", &resumeoff) != 0 ||
            nvlist_lookup_uint64(resume_nvl, "bytes", &bytes) != 0 ||
            nvlist_lookup_uint64(resume_nvl, "toguid", &toguid) != 0) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "resume token is corrupt"));
                return (zfs_error(hdl, EZFS_FAULT, errbuf));
        }
        fromguid = 0;
        (void) nvlist_lookup_uint64(resume_nvl, "fromguid", &fromguid);

        if (flags->saved) {
                (void) strcpy(name, toname);
        } else {
                error = guid_to_name(hdl, toname, toguid, B_FALSE, name);
                if (error != 0) {
                        if (zfs_dataset_exists(hdl, toname, ZFS_TYPE_DATASET)) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "'%s' is no longer the same snapshot "
                                    "used in the initial send"), toname);
                        } else {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "'%s' used in the initial send no "
                                    "longer exists"), toname);
                        }
                        return (zfs_error(hdl, EZFS_BADPATH, errbuf));
                }
        }

        zhp = zfs_open(hdl, name, ZFS_TYPE_DATASET);
        if (zhp == NULL) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "unable to access '%s'"), name);
                return (zfs_error(hdl, EZFS_BADPATH, errbuf));
        }

        if (nvlist_lookup_uint64_array(resume_nvl, "book_redact_snaps",
            &redact_snap_guids, (uint_t *)&num_redact_snaps) != 0) {
                num_redact_snaps = -1;
        }

        if (fromguid != 0) {
                if (guid_to_name_redact_snaps(hdl, toname, fromguid, B_TRUE,
                    redact_snap_guids, num_redact_snaps, name) != 0) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "incremental source %#llx no longer exists"),
                            (longlong_t)fromguid);
                        return (zfs_error(hdl, EZFS_BADPATH, errbuf));
                }
                fromname = name;
        }

        redact_snap_guids = NULL;

        if (nvlist_lookup_uint64_array(resume_nvl,
            zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS), &redact_snap_guids,
            (uint_t *)&num_redact_snaps) == 0) {
                char path[ZFS_MAX_DATASET_NAME_LEN];

                (void) strlcpy(path, toname, sizeof (path));
                char *at = strchr(path, '@');
                ASSERT3P(at, !=, NULL);

                *at = '\0';

                if ((error = find_redact_book(hdl, path, redact_snap_guids,
                    num_redact_snaps, &redact_book)) != 0) {
                        return (error);
                }
        }

        enum lzc_send_flags lzc_flags = lzc_flags_from_sendflags(flags) |
            lzc_flags_from_resume_nvl(resume_nvl);

        if (flags->verbosity != 0) {
                /*
                 * Some of these may have come from the resume token, set them
                 * here for size estimate purposes.
                 */
                sendflags_t tmpflags = *flags;
                if (lzc_flags & LZC_SEND_FLAG_LARGE_BLOCK)
                        tmpflags.largeblock = B_TRUE;
                if (lzc_flags & LZC_SEND_FLAG_COMPRESS)
                        tmpflags.compress = B_TRUE;
                if (lzc_flags & LZC_SEND_FLAG_EMBED_DATA)
                        tmpflags.embed_data = B_TRUE;
                if (lzc_flags & LZC_SEND_FLAG_RAW)
                        tmpflags.raw = B_TRUE;
                if (lzc_flags & LZC_SEND_FLAG_SAVED)
                        tmpflags.saved = B_TRUE;
                error = estimate_size(zhp, fromname, outfd, &tmpflags,
                    resumeobj, resumeoff, bytes, redact_book, errbuf);
        }

        if (!flags->dryrun) {
                progress_arg_t pa = { 0 };
                pthread_t tid;
                /*
                 * If progress reporting is requested, spawn a new thread to
                 * poll ZFS_IOC_SEND_PROGRESS at a regular interval.
                 */
                if (flags->progress) {
                        pa.pa_zhp = zhp;
                        pa.pa_fd = outfd;
                        pa.pa_parsable = flags->parsable;
                        pa.pa_estimate = B_FALSE;
                        pa.pa_verbosity = flags->verbosity;

                        error = pthread_create(&tid, NULL,
                            send_progress_thread, &pa);
                        if (error != 0) {
                                if (redact_book != NULL)
                                        free(redact_book);
                                zfs_close(zhp);
                                return (error);
                        }
                }

                error = lzc_send_resume_redacted(zhp->zfs_name, fromname, outfd,
                    lzc_flags, resumeobj, resumeoff, redact_book);
                if (redact_book != NULL)
                        free(redact_book);

                if (flags->progress) {
                        void *status = NULL;
                        (void) pthread_cancel(tid);
                        (void) pthread_join(tid, &status);
                        int error = (int)(uintptr_t)status;
                        if (error != 0 && status != PTHREAD_CANCELED) {
                                char errbuf[1024];
                                (void) snprintf(errbuf, sizeof (errbuf),
                                    dgettext(TEXT_DOMAIN,
                                    "progress thread exited nonzero"));
                                return (zfs_standard_error(hdl, error, errbuf));
                        }
                }

                char errbuf[1024];
                (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
                    "warning: cannot send '%s'"), zhp->zfs_name);

                zfs_close(zhp);

                switch (error) {
                case 0:
                        return (0);
                case EACCES:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "source key must be loaded"));
                        return (zfs_error(hdl, EZFS_CRYPTOFAILED, errbuf));
                case ESRCH:
                        if (lzc_exists(zhp->zfs_name)) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "incremental source could not be found"));
                        }
                        return (zfs_error(hdl, EZFS_NOENT, errbuf));

                case EXDEV:
                case ENOENT:
                case EDQUOT:
                case EFBIG:
                case EIO:
                case ENOLINK:
                case ENOSPC:
                case ENOSTR:
                case ENXIO:
                case EPIPE:
                case ERANGE:
                case EFAULT:
                case EROFS:
                        zfs_error_aux(hdl, "%s", strerror(errno));
                        return (zfs_error(hdl, EZFS_BADBACKUP, errbuf));

                default:
                        return (zfs_standard_error(hdl, errno, errbuf));
                }
        } else {
                if (redact_book != NULL)
                        free(redact_book);
        }

        zfs_close(zhp);

        return (error);
}

struct zfs_send_resume_impl {
        libzfs_handle_t *hdl;
        sendflags_t *flags;
        nvlist_t *resume_nvl;
};

static int
zfs_send_resume_impl_cb(int outfd, void *arg)
{
        struct zfs_send_resume_impl *zsri = arg;
        return (zfs_send_resume_impl_cb_impl(zsri->hdl, zsri->flags, outfd,
            zsri->resume_nvl));
}

static int
zfs_send_resume_impl(libzfs_handle_t *hdl, sendflags_t *flags, int outfd,
    nvlist_t *resume_nvl)
{
        struct zfs_send_resume_impl zsri = {
                .hdl = hdl,
                .flags = flags,
                .resume_nvl = resume_nvl,
        };
        return (lzc_send_wrapper(zfs_send_resume_impl_cb, outfd, &zsri));
}

int
zfs_send_resume(libzfs_handle_t *hdl, sendflags_t *flags, int outfd,
    const char *resume_token)
{
        int ret;
        char errbuf[1024];
        nvlist_t *resume_nvl;

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot resume send"));

        resume_nvl = zfs_send_resume_token_to_nvlist(hdl, resume_token);
        if (resume_nvl == NULL) {
                /*
                 * zfs_error_aux has already been set by
                 * zfs_send_resume_token_to_nvlist()
                 */
                return (zfs_error(hdl, EZFS_FAULT, errbuf));
        }

        ret = zfs_send_resume_impl(hdl, flags, outfd, resume_nvl);
        fnvlist_free(resume_nvl);

        return (ret);
}

int
zfs_send_saved(zfs_handle_t *zhp, sendflags_t *flags, int outfd,
    const char *resume_token)
{
        int ret;
        libzfs_handle_t *hdl = zhp->zfs_hdl;
        nvlist_t *saved_nvl = NULL, *resume_nvl = NULL;
        uint64_t saved_guid = 0, resume_guid = 0;
        uint64_t obj = 0, off = 0, bytes = 0;
        char token_buf[ZFS_MAXPROPLEN];
        char errbuf[1024];

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "saved send failed"));

        ret = zfs_prop_get(zhp, ZFS_PROP_RECEIVE_RESUME_TOKEN,
            token_buf, sizeof (token_buf), NULL, NULL, 0, B_TRUE);
        if (ret != 0)
                goto out;

        saved_nvl = zfs_send_resume_token_to_nvlist(hdl, token_buf);
        if (saved_nvl == NULL) {
                /*
                 * zfs_error_aux has already been set by
                 * zfs_send_resume_token_to_nvlist()
                 */
                ret = zfs_error(hdl, EZFS_FAULT, errbuf);
                goto out;
        }

        /*
         * If a resume token is provided we use the object and offset
         * from that instead of the default, which starts from the
         * beginning.
         */
        if (resume_token != NULL) {
                resume_nvl = zfs_send_resume_token_to_nvlist(hdl,
                    resume_token);
                if (resume_nvl == NULL) {
                        ret = zfs_error(hdl, EZFS_FAULT, errbuf);
                        goto out;
                }

                if (nvlist_lookup_uint64(resume_nvl, "object", &obj) != 0 ||
                    nvlist_lookup_uint64(resume_nvl, "offset", &off) != 0 ||
                    nvlist_lookup_uint64(resume_nvl, "bytes", &bytes) != 0 ||
                    nvlist_lookup_uint64(resume_nvl, "toguid",
                    &resume_guid) != 0) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "provided resume token is corrupt"));
                        ret = zfs_error(hdl, EZFS_FAULT, errbuf);
                        goto out;
                }

                if (nvlist_lookup_uint64(saved_nvl, "toguid",
                    &saved_guid)) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "dataset's resume token is corrupt"));
                        ret = zfs_error(hdl, EZFS_FAULT, errbuf);
                        goto out;
                }

                if (resume_guid != saved_guid) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "provided resume token does not match dataset"));
                        ret = zfs_error(hdl, EZFS_BADBACKUP, errbuf);
                        goto out;
                }
        }

        (void) nvlist_remove_all(saved_nvl, "object");
        fnvlist_add_uint64(saved_nvl, "object", obj);

        (void) nvlist_remove_all(saved_nvl, "offset");
        fnvlist_add_uint64(saved_nvl, "offset", off);

        (void) nvlist_remove_all(saved_nvl, "bytes");
        fnvlist_add_uint64(saved_nvl, "bytes", bytes);

        (void) nvlist_remove_all(saved_nvl, "toname");
        fnvlist_add_string(saved_nvl, "toname", zhp->zfs_name);

        ret = zfs_send_resume_impl(hdl, flags, outfd, saved_nvl);

out:
        fnvlist_free(saved_nvl);
        fnvlist_free(resume_nvl);
        return (ret);
}

/*
 * This function informs the target system that the recursive send is complete.
 * The record is also expected in the case of a send -p.
 */
static int
send_conclusion_record(int fd, zio_cksum_t *zc)
{
        dmu_replay_record_t drr = { 0 };
        drr.drr_type = DRR_END;
        if (zc != NULL)
                drr.drr_u.drr_end.drr_checksum = *zc;
        if (write(fd, &drr, sizeof (drr)) == -1) {
                return (errno);
        }
        return (0);
}

/*
 * This function is responsible for sending the records that contain the
 * necessary information for the target system's libzfs to be able to set the
 * properties of the filesystem being received, or to be able to prepare for
 * a recursive receive.
 *
 * The "zhp" argument is the handle of the snapshot we are sending
 * (the "tosnap").  The "from" argument is the short snapshot name (the part
 * after the @) of the incremental source.
 */
static int
send_prelim_records(zfs_handle_t *zhp, const char *from, int fd,
    boolean_t gather_props, boolean_t recursive, boolean_t verbose,
    boolean_t dryrun, boolean_t raw, boolean_t replicate, boolean_t skipmissing,
    boolean_t backup, boolean_t holds, boolean_t props, boolean_t doall,
    nvlist_t **fssp, avl_tree_t **fsavlp)
{
        int err = 0;
        char *packbuf = NULL;
        size_t buflen = 0;
        zio_cksum_t zc = { {0} };
        int featureflags = 0;
        /* name of filesystem/volume that contains snapshot we are sending */
        char tofs[ZFS_MAX_DATASET_NAME_LEN];
        /* short name of snap we are sending */
        char *tosnap = "";

        char errbuf[1024];
        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "warning: cannot send '%s'"), zhp->zfs_name);
        if (zhp->zfs_type == ZFS_TYPE_FILESYSTEM && zfs_prop_get_int(zhp,
            ZFS_PROP_VERSION) >= ZPL_VERSION_SA) {
                featureflags |= DMU_BACKUP_FEATURE_SA_SPILL;
        }

        if (holds)
                featureflags |= DMU_BACKUP_FEATURE_HOLDS;

        (void) strlcpy(tofs, zhp->zfs_name, ZFS_MAX_DATASET_NAME_LEN);
        char *at = strchr(tofs, '@');
        if (at != NULL) {
                *at = '\0';
                tosnap = at + 1;
        }

        if (gather_props) {
                nvlist_t *hdrnv = fnvlist_alloc();
                nvlist_t *fss = NULL;

                if (from != NULL)
                        fnvlist_add_string(hdrnv, "fromsnap", from);
                fnvlist_add_string(hdrnv, "tosnap", tosnap);
                if (!recursive)
                        fnvlist_add_boolean(hdrnv, "not_recursive");

                if (raw) {
                        fnvlist_add_boolean(hdrnv, "raw");
                }

                if ((err = gather_nvlist(zhp->zfs_hdl, tofs,
                    from, tosnap, recursive, raw, doall, replicate, skipmissing,
                    verbose, backup, holds, props, &fss, fsavlp)) != 0) {
                        return (zfs_error(zhp->zfs_hdl, EZFS_BADBACKUP,
                            errbuf));
                }
                /*
                 * Do not allow the size of the properties list to exceed
                 * the limit
                 */
                if ((fnvlist_size(fss) + fnvlist_size(hdrnv)) >
                    zhp->zfs_hdl->libzfs_max_nvlist) {
                        (void) snprintf(errbuf, sizeof (errbuf),
                            dgettext(TEXT_DOMAIN, "warning: cannot send '%s': "
                            "the size of the list of snapshots and properties "
                            "is too large to be received successfully.\n"
                            "Select a smaller number of snapshots to send.\n"),
                            zhp->zfs_name);
                        return (zfs_error(zhp->zfs_hdl, EZFS_NOSPC,
                            errbuf));
                }
                fnvlist_add_nvlist(hdrnv, "fss", fss);
                VERIFY0(nvlist_pack(hdrnv, &packbuf, &buflen, NV_ENCODE_XDR,
                    0));
                if (fssp != NULL) {
                        *fssp = fss;
                } else {
                        fnvlist_free(fss);
                }
                fnvlist_free(hdrnv);
        }

        if (!dryrun) {
                dmu_replay_record_t drr = { 0 };
                /* write first begin record */
                drr.drr_type = DRR_BEGIN;
                drr.drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
                DMU_SET_STREAM_HDRTYPE(drr.drr_u.drr_begin.
                    drr_versioninfo, DMU_COMPOUNDSTREAM);
                DMU_SET_FEATUREFLAGS(drr.drr_u.drr_begin.
                    drr_versioninfo, featureflags);
                if (snprintf(drr.drr_u.drr_begin.drr_toname,
                    sizeof (drr.drr_u.drr_begin.drr_toname), "%s@%s", tofs,
                    tosnap) >= sizeof (drr.drr_u.drr_begin.drr_toname)) {
                        return (zfs_error(zhp->zfs_hdl, EZFS_BADBACKUP,
                            errbuf));
                }
                drr.drr_payloadlen = buflen;

                err = dump_record(&drr, packbuf, buflen, &zc, fd);
                free(packbuf);
                if (err != 0) {
                        zfs_error_aux(zhp->zfs_hdl, "%s", strerror(err));
                        return (zfs_error(zhp->zfs_hdl, EZFS_BADBACKUP,
                            errbuf));
                }
                err = send_conclusion_record(fd, &zc);
                if (err != 0) {
                        zfs_error_aux(zhp->zfs_hdl, "%s", strerror(err));
                        return (zfs_error(zhp->zfs_hdl, EZFS_BADBACKUP,
                            errbuf));
                }
        }
        return (0);
}

/*
 * Generate a send stream.  The "zhp" argument is the filesystem/volume
 * that contains the snapshot to send.  The "fromsnap" argument is the
 * short name (the part after the '@') of the snapshot that is the
 * incremental source to send from (if non-NULL).  The "tosnap" argument
 * is the short name of the snapshot to send.
 *
 * The content of the send stream is the snapshot identified by
 * 'tosnap'.  Incremental streams are requested in two ways:
 *     - from the snapshot identified by "fromsnap" (if non-null) or
 *     - from the origin of the dataset identified by zhp, which must
 *       be a clone.  In this case, "fromsnap" is null and "fromorigin"
 *       is TRUE.
 *
 * The send stream is recursive (i.e. dumps a hierarchy of snapshots) and
 * uses a special header (with a hdrtype field of DMU_COMPOUNDSTREAM)
 * if "replicate" is set.  If "doall" is set, dump all the intermediate
 * snapshots. The DMU_COMPOUNDSTREAM header is used in the "doall"
 * case too. If "props" is set, send properties.
 *
 * Pre-wrapped (cf. lzc_send_wrapper()).
 */
static int
zfs_send_cb_impl(zfs_handle_t *zhp, const char *fromsnap, const char *tosnap,
    sendflags_t *flags, int outfd, snapfilter_cb_t filter_func,
    void *cb_arg, nvlist_t **debugnvp)
{
        char errbuf[1024];
        send_dump_data_t sdd = { 0 };
        int err = 0;
        nvlist_t *fss = NULL;
        avl_tree_t *fsavl = NULL;
        static uint64_t holdseq;
        int spa_version;
        FILE *fout;

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot send '%s'"), zhp->zfs_name);

        if (fromsnap && fromsnap[0] == '\0') {
                zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
                    "zero-length incremental source"));
                return (zfs_error(zhp->zfs_hdl, EZFS_NOENT, errbuf));
        }

        if (fromsnap) {
                char full_fromsnap_name[ZFS_MAX_DATASET_NAME_LEN];
                if (snprintf(full_fromsnap_name, sizeof (full_fromsnap_name),
                    "%s@%s", zhp->zfs_name, fromsnap) >=
                    sizeof (full_fromsnap_name)) {
                        err = EINVAL;
                        goto stderr_out;
                }
                zfs_handle_t *fromsnapn = zfs_open(zhp->zfs_hdl,
                    full_fromsnap_name, ZFS_TYPE_SNAPSHOT);
                if (fromsnapn == NULL) {
                        err = -1;
                        goto err_out;
                }
                zfs_close(fromsnapn);
        }

        if (flags->replicate || flags->doall || flags->props ||
            flags->holds || flags->backup) {
                char full_tosnap_name[ZFS_MAX_DATASET_NAME_LEN];
                if (snprintf(full_tosnap_name, sizeof (full_tosnap_name),
                    "%s@%s", zhp->zfs_name, tosnap) >=
                    sizeof (full_tosnap_name)) {
                        err = EINVAL;
                        goto stderr_out;
                }
                zfs_handle_t *tosnap = zfs_open(zhp->zfs_hdl,
                    full_tosnap_name, ZFS_TYPE_SNAPSHOT);
                if (tosnap == NULL) {
                        err = -1;
                        goto err_out;
                }
                err = send_prelim_records(tosnap, fromsnap, outfd,
                    flags->replicate || flags->props || flags->holds,
                    flags->replicate, flags->verbosity > 0, flags->dryrun,
                    flags->raw, flags->replicate, flags->skipmissing,
                    flags->backup, flags->holds, flags->props, flags->doall,
                    &fss, &fsavl);
                zfs_close(tosnap);
                if (err != 0)
                        goto err_out;
        }

        /* dump each stream */
        sdd.fromsnap = fromsnap;
        sdd.tosnap = tosnap;
        sdd.outfd = outfd;
        sdd.replicate = flags->replicate;
        sdd.doall = flags->doall;
        sdd.fromorigin = flags->fromorigin;
        sdd.fss = fss;
        sdd.fsavl = fsavl;
        sdd.verbosity = flags->verbosity;
        sdd.parsable = flags->parsable;
        sdd.progress = flags->progress;
        sdd.dryrun = flags->dryrun;
        sdd.large_block = flags->largeblock;
        sdd.embed_data = flags->embed_data;
        sdd.compress = flags->compress;
        sdd.raw = flags->raw;
        sdd.holds = flags->holds;
        sdd.filter_cb = filter_func;
        sdd.filter_cb_arg = cb_arg;
        if (debugnvp)
                sdd.debugnv = *debugnvp;
        if (sdd.verbosity != 0 && sdd.dryrun)
                sdd.std_out = B_TRUE;
        fout = sdd.std_out ? stdout : stderr;

        /*
         * Some flags require that we place user holds on the datasets that are
         * being sent so they don't get destroyed during the send. We can skip
         * this step if the pool is imported read-only since the datasets cannot
         * be destroyed.
         */
        if (!flags->dryrun && !zpool_get_prop_int(zfs_get_pool_handle(zhp),
            ZPOOL_PROP_READONLY, NULL) &&
            zfs_spa_version(zhp, &spa_version) == 0 &&
            spa_version >= SPA_VERSION_USERREFS &&
            (flags->doall || flags->replicate)) {
                ++holdseq;
                (void) snprintf(sdd.holdtag, sizeof (sdd.holdtag),
                    ".send-%d-%llu", getpid(), (u_longlong_t)holdseq);
                sdd.cleanup_fd = open(ZFS_DEV, O_RDWR | O_CLOEXEC);
                if (sdd.cleanup_fd < 0) {
                        err = errno;
                        goto stderr_out;
                }
                sdd.snapholds = fnvlist_alloc();
        } else {
                sdd.cleanup_fd = -1;
                sdd.snapholds = NULL;
        }

        if (flags->verbosity != 0 || sdd.snapholds != NULL) {
                /*
                 * Do a verbose no-op dry run to get all the verbose output
                 * or to gather snapshot hold's before generating any data,
                 * then do a non-verbose real run to generate the streams.
                 */
                sdd.dryrun = B_TRUE;
                err = dump_filesystems(zhp, &sdd);

                if (err != 0)
                        goto stderr_out;

                if (flags->verbosity != 0) {
                        if (flags->parsable) {
                                (void) fprintf(fout, "size\t%llu\n",
                                    (longlong_t)sdd.size);
                        } else {
                                char buf[16];
                                zfs_nicebytes(sdd.size, buf, sizeof (buf));
                                (void) fprintf(fout, dgettext(TEXT_DOMAIN,
                                    "total estimated size is %s\n"), buf);
                        }
                }

                /* Ensure no snaps found is treated as an error. */
                if (!sdd.seento) {
                        err = ENOENT;
                        goto err_out;
                }

                /* Skip the second run if dryrun was requested. */
                if (flags->dryrun)
                        goto err_out;

                if (sdd.snapholds != NULL) {
                        err = zfs_hold_nvl(zhp, sdd.cleanup_fd, sdd.snapholds);
                        if (err != 0)
                                goto stderr_out;

                        fnvlist_free(sdd.snapholds);
                        sdd.snapholds = NULL;
                }

                sdd.dryrun = B_FALSE;
                sdd.verbosity = 0;
        }

        err = dump_filesystems(zhp, &sdd);
        fsavl_destroy(fsavl);
        fnvlist_free(fss);

        /* Ensure no snaps found is treated as an error. */
        if (err == 0 && !sdd.seento)
                err = ENOENT;

        if (sdd.cleanup_fd != -1) {
                VERIFY(0 == close(sdd.cleanup_fd));
                sdd.cleanup_fd = -1;
        }

        if (!flags->dryrun && (flags->replicate || flags->doall ||
            flags->props || flags->backup || flags->holds)) {
                /*
                 * write final end record.  NB: want to do this even if
                 * there was some error, because it might not be totally
                 * failed.
                 */
                err = send_conclusion_record(outfd, NULL);
                if (err != 0)
                        return (zfs_standard_error(zhp->zfs_hdl, err, errbuf));
        }

        return (err || sdd.err);

stderr_out:
        err = zfs_standard_error(zhp->zfs_hdl, err, errbuf);
err_out:
        fsavl_destroy(fsavl);
        fnvlist_free(fss);
        fnvlist_free(sdd.snapholds);

        if (sdd.cleanup_fd != -1)
                VERIFY(0 == close(sdd.cleanup_fd));
        return (err);
}

struct zfs_send {
        zfs_handle_t *zhp;
        const char *fromsnap;
        const char *tosnap;
        sendflags_t *flags;
        snapfilter_cb_t *filter_func;
        void *cb_arg;
        nvlist_t **debugnvp;
};

static int
zfs_send_cb(int outfd, void *arg)
{
        struct zfs_send *zs = arg;
        return (zfs_send_cb_impl(zs->zhp, zs->fromsnap, zs->tosnap, zs->flags,
            outfd, zs->filter_func, zs->cb_arg, zs->debugnvp));
}

int
zfs_send(zfs_handle_t *zhp, const char *fromsnap, const char *tosnap,
    sendflags_t *flags, int outfd, snapfilter_cb_t filter_func,
    void *cb_arg, nvlist_t **debugnvp)
{
        struct zfs_send arg = {
                .zhp = zhp,
                .fromsnap = fromsnap,
                .tosnap = tosnap,
                .flags = flags,
                .filter_func = filter_func,
                .cb_arg = cb_arg,
                .debugnvp = debugnvp,
        };
        return (lzc_send_wrapper(zfs_send_cb, outfd, &arg));
}


static zfs_handle_t *
name_to_dir_handle(libzfs_handle_t *hdl, const char *snapname)
{
        char dirname[ZFS_MAX_DATASET_NAME_LEN];
        (void) strlcpy(dirname, snapname, ZFS_MAX_DATASET_NAME_LEN);
        char *c = strchr(dirname, '@');
        if (c != NULL)
                *c = '\0';
        return (zfs_open(hdl, dirname, ZFS_TYPE_DATASET));
}

/*
 * Returns B_TRUE if earlier is an earlier snapshot in later's timeline; either
 * an earlier snapshot in the same filesystem, or a snapshot before later's
 * origin, or it's origin's origin, etc.
 */
static boolean_t
snapshot_is_before(zfs_handle_t *earlier, zfs_handle_t *later)
{
        boolean_t ret;
        uint64_t later_txg =
            (later->zfs_type == ZFS_TYPE_FILESYSTEM ||
            later->zfs_type == ZFS_TYPE_VOLUME ?
            UINT64_MAX : zfs_prop_get_int(later, ZFS_PROP_CREATETXG));
        uint64_t earlier_txg = zfs_prop_get_int(earlier, ZFS_PROP_CREATETXG);

        if (earlier_txg >= later_txg)
                return (B_FALSE);

        zfs_handle_t *earlier_dir = name_to_dir_handle(earlier->zfs_hdl,
            earlier->zfs_name);
        zfs_handle_t *later_dir = name_to_dir_handle(later->zfs_hdl,
            later->zfs_name);

        if (strcmp(earlier_dir->zfs_name, later_dir->zfs_name) == 0) {
                zfs_close(earlier_dir);
                zfs_close(later_dir);
                return (B_TRUE);
        }

        char clonename[ZFS_MAX_DATASET_NAME_LEN];
        if (zfs_prop_get(later_dir, ZFS_PROP_ORIGIN, clonename,
            ZFS_MAX_DATASET_NAME_LEN, NULL, NULL, 0, B_TRUE) != 0) {
                zfs_close(earlier_dir);
                zfs_close(later_dir);
                return (B_FALSE);
        }

        zfs_handle_t *origin = zfs_open(earlier->zfs_hdl, clonename,
            ZFS_TYPE_DATASET);
        uint64_t origin_txg = zfs_prop_get_int(origin, ZFS_PROP_CREATETXG);

        /*
         * If "earlier" is exactly the origin, then
         * snapshot_is_before(earlier, origin) will return false (because
         * they're the same).
         */
        if (origin_txg == earlier_txg &&
            strcmp(origin->zfs_name, earlier->zfs_name) == 0) {
                zfs_close(earlier_dir);
                zfs_close(later_dir);
                zfs_close(origin);
                return (B_TRUE);
        }
        zfs_close(earlier_dir);
        zfs_close(later_dir);

        ret = snapshot_is_before(earlier, origin);
        zfs_close(origin);
        return (ret);
}

/*
 * The "zhp" argument is the handle of the dataset to send (typically a
 * snapshot).  The "from" argument is the full name of the snapshot or
 * bookmark that is the incremental source.
 *
 * Pre-wrapped (cf. lzc_send_wrapper()).
 */
static int
zfs_send_one_cb_impl(zfs_handle_t *zhp, const char *from, int fd,
    sendflags_t *flags, const char *redactbook)
{
        int err;
        libzfs_handle_t *hdl = zhp->zfs_hdl;
        char *name = zhp->zfs_name;
        pthread_t ptid;
        progress_arg_t pa = { 0 };

        char errbuf[1024];
        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "warning: cannot send '%s'"), name);

        if (from != NULL && strchr(from, '@')) {
                zfs_handle_t *from_zhp = zfs_open(hdl, from,
                    ZFS_TYPE_DATASET);
                if (from_zhp == NULL)
                        return (-1);
                if (!snapshot_is_before(from_zhp, zhp)) {
                        zfs_close(from_zhp);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "not an earlier snapshot from the same fs"));
                        return (zfs_error(hdl, EZFS_CROSSTARGET, errbuf));
                }
                zfs_close(from_zhp);
        }

        if (redactbook != NULL) {
                char bookname[ZFS_MAX_DATASET_NAME_LEN];
                nvlist_t *redact_snaps;
                zfs_handle_t *book_zhp;
                char *at, *pound;
                int dsnamelen;

                pound = strchr(redactbook, '#');
                if (pound != NULL)
                        redactbook = pound + 1;
                at = strchr(name, '@');
                if (at == NULL) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "cannot do a redacted send to a filesystem"));
                        return (zfs_error(hdl, EZFS_BADTYPE, errbuf));
                }
                dsnamelen = at - name;
                if (snprintf(bookname, sizeof (bookname), "%.*s#%s",
                    dsnamelen, name, redactbook)
                    >= sizeof (bookname)) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "invalid bookmark name"));
                        return (zfs_error(hdl, EZFS_INVALIDNAME, errbuf));
                }
                book_zhp = zfs_open(hdl, bookname, ZFS_TYPE_BOOKMARK);
                if (book_zhp == NULL)
                        return (-1);
                if (nvlist_lookup_nvlist(book_zhp->zfs_props,
                    zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS),
                    &redact_snaps) != 0 || redact_snaps == NULL) {
                        zfs_close(book_zhp);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "not a redaction bookmark"));
                        return (zfs_error(hdl, EZFS_BADTYPE, errbuf));
                }
                zfs_close(book_zhp);
        }

        /*
         * Send fs properties
         */
        if (flags->props || flags->holds || flags->backup) {
                /*
                 * Note: the header generated by send_prelim_records()
                 * assumes that the incremental source is in the same
                 * filesystem/volume as the target (which is a requirement
                 * when doing "zfs send -R").  But that isn't always the
                 * case here (e.g. send from snap in origin, or send from
                 * bookmark).  We pass from=NULL, which will omit this
                 * information from the prelim records; it isn't used
                 * when receiving this type of stream.
                 */
                err = send_prelim_records(zhp, NULL, fd, B_TRUE, B_FALSE,
                    flags->verbosity > 0, flags->dryrun, flags->raw,
                    flags->replicate, B_FALSE, flags->backup, flags->holds,
                    flags->props, flags->doall, NULL, NULL);
                if (err != 0)
                        return (err);
        }

        /*
         * Perform size estimate if verbose was specified.
         */
        if (flags->verbosity != 0) {
                err = estimate_size(zhp, from, fd, flags, 0, 0, 0, redactbook,
                    errbuf);
                if (err != 0)
                        return (err);
        }

        if (flags->dryrun)
                return (0);

        /*
         * If progress reporting is requested, spawn a new thread to poll
         * ZFS_IOC_SEND_PROGRESS at a regular interval.
         */
        if (flags->progress) {
                pa.pa_zhp = zhp;
                pa.pa_fd = fd;
                pa.pa_parsable = flags->parsable;
                pa.pa_estimate = B_FALSE;
                pa.pa_verbosity = flags->verbosity;

                err = pthread_create(&ptid, NULL,
                    send_progress_thread, &pa);
                if (err != 0) {
                        zfs_error_aux(zhp->zfs_hdl, "%s", strerror(errno));
                        return (zfs_error(zhp->zfs_hdl,
                            EZFS_THREADCREATEFAILED, errbuf));
                }
        }

        err = lzc_send_redacted(name, from, fd,
            lzc_flags_from_sendflags(flags), redactbook);

        if (flags->progress) {
                void *status = NULL;
                if (err != 0)
                        (void) pthread_cancel(ptid);
                (void) pthread_join(ptid, &status);
                int error = (int)(uintptr_t)status;
                if (error != 0 && status != PTHREAD_CANCELED)
                        return (zfs_standard_error_fmt(hdl, error,
                            dgettext(TEXT_DOMAIN,
                            "progress thread exited nonzero")));
        }

        if (err == 0 && (flags->props || flags->holds || flags->backup)) {
                /* Write the final end record. */
                err = send_conclusion_record(fd, NULL);
                if (err != 0)
                        return (zfs_standard_error(hdl, err, errbuf));
        }
        if (err != 0) {
                switch (errno) {
                case EXDEV:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "not an earlier snapshot from the same fs"));
                        return (zfs_error(hdl, EZFS_CROSSTARGET, errbuf));

                case ENOENT:
                case ESRCH:
                        if (lzc_exists(name)) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "incremental source (%s) does not exist"),
                                    from);
                        }
                        return (zfs_error(hdl, EZFS_NOENT, errbuf));

                case EACCES:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "dataset key must be loaded"));
                        return (zfs_error(hdl, EZFS_CRYPTOFAILED, errbuf));

                case EBUSY:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "target is busy; if a filesystem, "
                            "it must not be mounted"));
                        return (zfs_error(hdl, EZFS_BUSY, errbuf));

                case EDQUOT:
                case EFAULT:
                case EFBIG:
                case EINVAL:
                case EIO:
                case ENOLINK:
                case ENOSPC:
                case ENOSTR:
                case ENXIO:
                case EPIPE:
                case ERANGE:
                case EROFS:
                        zfs_error_aux(hdl, "%s", strerror(errno));
                        return (zfs_error(hdl, EZFS_BADBACKUP, errbuf));

                default:
                        return (zfs_standard_error(hdl, errno, errbuf));
                }
        }
        return (err != 0);
}

struct zfs_send_one {
        zfs_handle_t *zhp;
        const char *from;
        sendflags_t *flags;
        const char *redactbook;
};

static int
zfs_send_one_cb(int fd, void *arg)
{
        struct zfs_send_one *zso = arg;
        return (zfs_send_one_cb_impl(zso->zhp, zso->from, fd, zso->flags,
            zso->redactbook));
}

int
zfs_send_one(zfs_handle_t *zhp, const char *from, int fd, sendflags_t *flags,
    const char *redactbook)
{
        struct zfs_send_one zso = {
                .zhp = zhp,
                .from = from,
                .flags = flags,
                .redactbook = redactbook,
        };
        return (lzc_send_wrapper(zfs_send_one_cb, fd, &zso));
}

/*
 * Routines specific to "zfs recv"
 */

static int
recv_read(libzfs_handle_t *hdl, int fd, void *buf, int ilen,
    boolean_t byteswap, zio_cksum_t *zc)
{
        char *cp = buf;
        int rv;
        int len = ilen;

        do {
                rv = read(fd, cp, len);
                cp += rv;
                len -= rv;
        } while (rv > 0);

        if (rv < 0 || len != 0) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "failed to read from stream"));
                return (zfs_error(hdl, EZFS_BADSTREAM, dgettext(TEXT_DOMAIN,
                    "cannot receive")));
        }

        if (zc) {
                if (byteswap)
                        fletcher_4_incremental_byteswap(buf, ilen, zc);
                else
                        fletcher_4_incremental_native(buf, ilen, zc);
        }
        return (0);
}

static int
recv_read_nvlist(libzfs_handle_t *hdl, int fd, int len, nvlist_t **nvp,
    boolean_t byteswap, zio_cksum_t *zc)
{
        char *buf;
        int err;

        buf = zfs_alloc(hdl, len);
        if (buf == NULL)
                return (ENOMEM);

        if (len > hdl->libzfs_max_nvlist) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "nvlist too large"));
                free(buf);
                return (ENOMEM);
        }

        err = recv_read(hdl, fd, buf, len, byteswap, zc);
        if (err != 0) {
                free(buf);
                return (err);
        }

        err = nvlist_unpack(buf, len, nvp, 0);
        free(buf);
        if (err != 0) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                    "stream (malformed nvlist)"));
                return (EINVAL);
        }
        return (0);
}

/*
 * Returns the grand origin (origin of origin of origin...) of a given handle.
 * If this dataset is not a clone, it simply returns a copy of the original
 * handle.
 */
static zfs_handle_t *
recv_open_grand_origin(zfs_handle_t *zhp)
{
        char origin[ZFS_MAX_DATASET_NAME_LEN];
        zprop_source_t src;
        zfs_handle_t *ozhp = zfs_handle_dup(zhp);

        while (ozhp != NULL) {
                if (zfs_prop_get(ozhp, ZFS_PROP_ORIGIN, origin,
                    sizeof (origin), &src, NULL, 0, B_FALSE) != 0)
                        break;

                (void) zfs_close(ozhp);
                ozhp = zfs_open(zhp->zfs_hdl, origin, ZFS_TYPE_FILESYSTEM);
        }

        return (ozhp);
}

static int
recv_rename_impl(zfs_handle_t *zhp, const char *name, const char *newname)
{
        int err;
        zfs_handle_t *ozhp = NULL;

        /*
         * Attempt to rename the dataset. If it fails with EACCES we have
         * attempted to rename the dataset outside of its encryption root.
         * Force the dataset to become an encryption root and try again.
         */
        err = lzc_rename(name, newname);
        if (err == EACCES) {
                ozhp = recv_open_grand_origin(zhp);
                if (ozhp == NULL) {
                        err = ENOENT;
                        goto out;
                }

                err = lzc_change_key(ozhp->zfs_name, DCP_CMD_FORCE_NEW_KEY,
                    NULL, NULL, 0);
                if (err != 0)
                        goto out;

                err = lzc_rename(name, newname);
        }

out:
        if (ozhp != NULL)
                zfs_close(ozhp);
        return (err);
}

static int
recv_rename(libzfs_handle_t *hdl, const char *name, const char *tryname,
    int baselen, char *newname, recvflags_t *flags)
{
        static int seq;
        int err;
        prop_changelist_t *clp = NULL;
        zfs_handle_t *zhp = NULL;

        zhp = zfs_open(hdl, name, ZFS_TYPE_DATASET);
        if (zhp == NULL) {
                err = -1;
                goto out;
        }
        clp = changelist_gather(zhp, ZFS_PROP_NAME, 0,
            flags->force ? MS_FORCE : 0);
        if (clp == NULL) {
                err = -1;
                goto out;
        }
        err = changelist_prefix(clp);
        if (err)
                goto out;

        if (tryname) {
                (void) strcpy(newname, tryname);
                if (flags->verbose) {
                        (void) printf("attempting rename %s to %s\n",
                            name, newname);
                }
                err = recv_rename_impl(zhp, name, newname);
                if (err == 0)
                        changelist_rename(clp, name, tryname);
        } else {
                err = ENOENT;
        }

        if (err != 0 && strncmp(name + baselen, "recv-", 5) != 0) {
                seq++;

                (void) snprintf(newname, ZFS_MAX_DATASET_NAME_LEN,
                    "%.*srecv-%u-%u", baselen, name, getpid(), seq);

                if (flags->verbose) {
                        (void) printf("failed - trying rename %s to %s\n",
                            name, newname);
                }
                err = recv_rename_impl(zhp, name, newname);
                if (err == 0)
                        changelist_rename(clp, name, newname);
                if (err && flags->verbose) {
                        (void) printf("failed (%u) - "
                            "will try again on next pass\n", errno);
                }
                err = EAGAIN;
        } else if (flags->verbose) {
                if (err == 0)
                        (void) printf("success\n");
                else
                        (void) printf("failed (%u)\n", errno);
        }

        (void) changelist_postfix(clp);

out:
        if (clp != NULL)
                changelist_free(clp);
        if (zhp != NULL)
                zfs_close(zhp);

        return (err);
}

static int
recv_promote(libzfs_handle_t *hdl, const char *fsname,
    const char *origin_fsname, recvflags_t *flags)
{
        int err;
        zfs_cmd_t zc = {"\0"};
        zfs_handle_t *zhp = NULL, *ozhp = NULL;

        if (flags->verbose)
                (void) printf("promoting %s\n", fsname);

        (void) strlcpy(zc.zc_value, origin_fsname, sizeof (zc.zc_value));
        (void) strlcpy(zc.zc_name, fsname, sizeof (zc.zc_name));

        /*
         * Attempt to promote the dataset. If it fails with EACCES the
         * promotion would cause this dataset to leave its encryption root.
         * Force the origin to become an encryption root and try again.
         */
        err = zfs_ioctl(hdl, ZFS_IOC_PROMOTE, &zc);
        if (err == EACCES) {
                zhp = zfs_open(hdl, fsname, ZFS_TYPE_DATASET);
                if (zhp == NULL) {
                        err = -1;
                        goto out;
                }

                ozhp = recv_open_grand_origin(zhp);
                if (ozhp == NULL) {
                        err = -1;
                        goto out;
                }

                err = lzc_change_key(ozhp->zfs_name, DCP_CMD_FORCE_NEW_KEY,
                    NULL, NULL, 0);
                if (err != 0)
                        goto out;

                err = zfs_ioctl(hdl, ZFS_IOC_PROMOTE, &zc);
        }

out:
        if (zhp != NULL)
                zfs_close(zhp);
        if (ozhp != NULL)
                zfs_close(ozhp);

        return (err);
}

static int
recv_destroy(libzfs_handle_t *hdl, const char *name, int baselen,
    char *newname, recvflags_t *flags)
{
        int err = 0;
        prop_changelist_t *clp;
        zfs_handle_t *zhp;
        boolean_t defer = B_FALSE;
        int spa_version;

        zhp = zfs_open(hdl, name, ZFS_TYPE_DATASET);
        if (zhp == NULL)
                return (-1);
        zfs_type_t type = zfs_get_type(zhp);
        if (type == ZFS_TYPE_SNAPSHOT &&
            zfs_spa_version(zhp, &spa_version) == 0 &&
            spa_version >= SPA_VERSION_USERREFS)
                defer = B_TRUE;
        clp = changelist_gather(zhp, ZFS_PROP_NAME, 0,
            flags->force ? MS_FORCE : 0);
        zfs_close(zhp);
        if (clp == NULL)
                return (-1);

        err = changelist_prefix(clp);
        if (err)
                return (err);

        if (flags->verbose)
                (void) printf("attempting destroy %s\n", name);
        if (type == ZFS_TYPE_SNAPSHOT) {
                nvlist_t *nv = fnvlist_alloc();
                fnvlist_add_boolean(nv, name);
                err = lzc_destroy_snaps(nv, defer, NULL);
                fnvlist_free(nv);
        } else {
                err = lzc_destroy(name);
        }
        if (err == 0) {
                if (flags->verbose)
                        (void) printf("success\n");
                changelist_remove(clp, name);
        }

        (void) changelist_postfix(clp);
        changelist_free(clp);

        /*
         * Deferred destroy might destroy the snapshot or only mark it to be
         * destroyed later, and it returns success in either case.
         */
        if (err != 0 || (defer && zfs_dataset_exists(hdl, name,
            ZFS_TYPE_SNAPSHOT))) {
                err = recv_rename(hdl, name, NULL, baselen, newname, flags);
        }

        return (err);
}

typedef struct guid_to_name_data {
        uint64_t guid;
        boolean_t bookmark_ok;
        char *name;
        char *skip;
        uint64_t *redact_snap_guids;
        uint64_t num_redact_snaps;
} guid_to_name_data_t;

static boolean_t
redact_snaps_match(zfs_handle_t *zhp, guid_to_name_data_t *gtnd)
{
        uint64_t *bmark_snaps;
        uint_t bmark_num_snaps;
        nvlist_t *nvl;
        if (zhp->zfs_type != ZFS_TYPE_BOOKMARK)
                return (B_FALSE);

        nvl = fnvlist_lookup_nvlist(zhp->zfs_props,
            zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS));
        bmark_snaps = fnvlist_lookup_uint64_array(nvl, ZPROP_VALUE,
            &bmark_num_snaps);
        if (bmark_num_snaps != gtnd->num_redact_snaps)
                return (B_FALSE);
        int i = 0;
        for (; i < bmark_num_snaps; i++) {
                int j = 0;
                for (; j < bmark_num_snaps; j++) {
                        if (bmark_snaps[i] == gtnd->redact_snap_guids[j])
                                break;
                }
                if (j == bmark_num_snaps)
                        break;
        }
        return (i == bmark_num_snaps);
}

static int
guid_to_name_cb(zfs_handle_t *zhp, void *arg)
{
        guid_to_name_data_t *gtnd = arg;
        const char *slash;
        int err;

        if (gtnd->skip != NULL &&
            (slash = strrchr(zhp->zfs_name, '/')) != NULL &&
            strcmp(slash + 1, gtnd->skip) == 0) {
                zfs_close(zhp);
                return (0);
        }

        if (zfs_prop_get_int(zhp, ZFS_PROP_GUID) == gtnd->guid &&
            (gtnd->num_redact_snaps == -1 || redact_snaps_match(zhp, gtnd))) {
                (void) strcpy(gtnd->name, zhp->zfs_name);
                zfs_close(zhp);
                return (EEXIST);
        }

        err = zfs_iter_children(zhp, guid_to_name_cb, gtnd);
        if (err != EEXIST && gtnd->bookmark_ok)
                err = zfs_iter_bookmarks(zhp, guid_to_name_cb, gtnd);
        zfs_close(zhp);
        return (err);
}

/*
 * Attempt to find the local dataset associated with this guid.  In the case of
 * multiple matches, we attempt to find the "best" match by searching
 * progressively larger portions of the hierarchy.  This allows one to send a
 * tree of datasets individually and guarantee that we will find the source
 * guid within that hierarchy, even if there are multiple matches elsewhere.
 *
 * If num_redact_snaps is not -1, we attempt to find a redaction bookmark with
 * the specified number of redaction snapshots.  If num_redact_snaps isn't 0 or
 * -1, then redact_snap_guids will be an array of the guids of the snapshots the
 * redaction bookmark was created with.  If num_redact_snaps is -1, then we will
 * attempt to find a snapshot or bookmark (if bookmark_ok is passed) with the
 * given guid.  Note that a redaction bookmark can be returned if
 * num_redact_snaps == -1.
 */
static int
guid_to_name_redact_snaps(libzfs_handle_t *hdl, const char *parent,
    uint64_t guid, boolean_t bookmark_ok, uint64_t *redact_snap_guids,
    uint64_t num_redact_snaps, char *name)
{
        char pname[ZFS_MAX_DATASET_NAME_LEN];
        guid_to_name_data_t gtnd;

        gtnd.guid = guid;
        gtnd.bookmark_ok = bookmark_ok;
        gtnd.name = name;
        gtnd.skip = NULL;
        gtnd.redact_snap_guids = redact_snap_guids;
        gtnd.num_redact_snaps = num_redact_snaps;

        /*
         * Search progressively larger portions of the hierarchy, starting
         * with the filesystem specified by 'parent'.  This will
         * select the "most local" version of the origin snapshot in the case
         * that there are multiple matching snapshots in the system.
         */
        (void) strlcpy(pname, parent, sizeof (pname));
        char *cp = strrchr(pname, '@');
        if (cp == NULL)
                cp = strchr(pname, '\0');
        for (; cp != NULL; cp = strrchr(pname, '/')) {
                /* Chop off the last component and open the parent */
                *cp = '\0';
                zfs_handle_t *zhp = make_dataset_handle(hdl, pname);

                if (zhp == NULL)
                        continue;
                int err = guid_to_name_cb(zfs_handle_dup(zhp), &gtnd);
                if (err != EEXIST)
                        err = zfs_iter_children(zhp, guid_to_name_cb, &gtnd);
                if (err != EEXIST && bookmark_ok)
                        err = zfs_iter_bookmarks(zhp, guid_to_name_cb, &gtnd);
                zfs_close(zhp);
                if (err == EEXIST)
                        return (0);

                /*
                 * Remember the last portion of the dataset so we skip it next
                 * time through (as we've already searched that portion of the
                 * hierarchy).
                 */
                gtnd.skip = strrchr(pname, '/') + 1;
        }

        return (ENOENT);
}

static int
guid_to_name(libzfs_handle_t *hdl, const char *parent, uint64_t guid,
    boolean_t bookmark_ok, char *name)
{
        return (guid_to_name_redact_snaps(hdl, parent, guid, bookmark_ok, NULL,
            -1, name));
}

/*
 * Return +1 if guid1 is before guid2, 0 if they are the same, and -1 if
 * guid1 is after guid2.
 */
static int
created_before(libzfs_handle_t *hdl, avl_tree_t *avl,
    uint64_t guid1, uint64_t guid2)
{
        nvlist_t *nvfs;
        char *fsname = NULL, *snapname = NULL;
        char buf[ZFS_MAX_DATASET_NAME_LEN];
        int rv;
        zfs_handle_t *guid1hdl, *guid2hdl;
        uint64_t create1, create2;

        if (guid2 == 0)
                return (0);
        if (guid1 == 0)
                return (1);

        nvfs = fsavl_find(avl, guid1, &snapname);
        fsname = fnvlist_lookup_string(nvfs, "name");
        (void) snprintf(buf, sizeof (buf), "%s@%s", fsname, snapname);
        guid1hdl = zfs_open(hdl, buf, ZFS_TYPE_SNAPSHOT);
        if (guid1hdl == NULL)
                return (-1);

        nvfs = fsavl_find(avl, guid2, &snapname);
        fsname = fnvlist_lookup_string(nvfs, "name");
        (void) snprintf(buf, sizeof (buf), "%s@%s", fsname, snapname);
        guid2hdl = zfs_open(hdl, buf, ZFS_TYPE_SNAPSHOT);
        if (guid2hdl == NULL) {
                zfs_close(guid1hdl);
                return (-1);
        }

        create1 = zfs_prop_get_int(guid1hdl, ZFS_PROP_CREATETXG);
        create2 = zfs_prop_get_int(guid2hdl, ZFS_PROP_CREATETXG);

        if (create1 < create2)
                rv = -1;
        else if (create1 > create2)
                rv = +1;
        else
                rv = 0;

        zfs_close(guid1hdl);
        zfs_close(guid2hdl);

        return (rv);
}

/*
 * This function reestablishes the hierarchy of encryption roots after a
 * recursive incremental receive has completed. This must be done after the
 * second call to recv_incremental_replication() has renamed and promoted all
 * sent datasets to their final locations in the dataset hierarchy.
 */
static int
recv_fix_encryption_hierarchy(libzfs_handle_t *hdl, const char *top_zfs,
    nvlist_t *stream_nv)
{
        int err;
        nvpair_t *fselem = NULL;
        nvlist_t *stream_fss;

        stream_fss = fnvlist_lookup_nvlist(stream_nv, "fss");

        while ((fselem = nvlist_next_nvpair(stream_fss, fselem)) != NULL) {
                zfs_handle_t *zhp = NULL;
                uint64_t crypt;
                nvlist_t *snaps, *props, *stream_nvfs = NULL;
                nvpair_t *snapel = NULL;
                boolean_t is_encroot, is_clone, stream_encroot;
                char *cp;
                char *stream_keylocation = NULL;
                char keylocation[MAXNAMELEN];
                char fsname[ZFS_MAX_DATASET_NAME_LEN];

                keylocation[0] = '\0';
                stream_nvfs = fnvpair_value_nvlist(fselem);
                snaps = fnvlist_lookup_nvlist(stream_nvfs, "snaps");
                props = fnvlist_lookup_nvlist(stream_nvfs, "props");
                stream_encroot = nvlist_exists(stream_nvfs, "is_encroot");

                /* find a snapshot from the stream that exists locally */
                err = ENOENT;
                while ((snapel = nvlist_next_nvpair(snaps, snapel)) != NULL) {
                        uint64_t guid;

                        guid = fnvpair_value_uint64(snapel);
                        err = guid_to_name(hdl, top_zfs, guid, B_FALSE,
                            fsname);
                        if (err == 0)
                                break;
                }

                if (err != 0)
                        continue;

                cp = strchr(fsname, '@');
                if (cp != NULL)
                        *cp = '\0';

                zhp = zfs_open(hdl, fsname, ZFS_TYPE_DATASET);
                if (zhp == NULL) {
                        err = ENOENT;
                        goto error;
                }

                crypt = zfs_prop_get_int(zhp, ZFS_PROP_ENCRYPTION);
                is_clone = zhp->zfs_dmustats.dds_origin[0] != '\0';
                (void) zfs_crypto_get_encryption_root(zhp, &is_encroot, NULL);

                /* we don't need to do anything for unencrypted datasets */
                if (crypt == ZIO_CRYPT_OFF) {
                        zfs_close(zhp);
                        continue;
                }

                /*
                 * If the dataset is flagged as an encryption root, was not
                 * received as a clone and is not currently an encryption root,
                 * force it to become one. Fixup the keylocation if necessary.
                 */
                if (stream_encroot) {
                        if (!is_clone && !is_encroot) {
                                err = lzc_change_key(fsname,
                                    DCP_CMD_FORCE_NEW_KEY, NULL, NULL, 0);
                                if (err != 0) {
                                        zfs_close(zhp);
                                        goto error;
                                }
                        }

                        stream_keylocation = fnvlist_lookup_string(props,
                            zfs_prop_to_name(ZFS_PROP_KEYLOCATION));

                        /*
                         * Refresh the properties in case the call to
                         * lzc_change_key() changed the value.
                         */
                        zfs_refresh_properties(zhp);
                        err = zfs_prop_get(zhp, ZFS_PROP_KEYLOCATION,
                            keylocation, sizeof (keylocation), NULL, NULL,
                            0, B_TRUE);
                        if (err != 0) {
                                zfs_close(zhp);
                                goto error;
                        }

                        if (strcmp(keylocation, stream_keylocation) != 0) {
                                err = zfs_prop_set(zhp,
                                    zfs_prop_to_name(ZFS_PROP_KEYLOCATION),
                                    stream_keylocation);
                                if (err != 0) {
                                        zfs_close(zhp);
                                        goto error;
                                }
                        }
                }

                /*
                 * If the dataset is not flagged as an encryption root and is
                 * currently an encryption root, force it to inherit from its
                 * parent. The root of a raw send should never be
                 * force-inherited.
                 */
                if (!stream_encroot && is_encroot &&
                    strcmp(top_zfs, fsname) != 0) {
                        err = lzc_change_key(fsname, DCP_CMD_FORCE_INHERIT,
                            NULL, NULL, 0);
                        if (err != 0) {
                                zfs_close(zhp);
                                goto error;
                        }
                }

                zfs_close(zhp);
        }

        return (0);

error:
        return (err);
}

static int
recv_incremental_replication(libzfs_handle_t *hdl, const char *tofs,
    recvflags_t *flags, nvlist_t *stream_nv, avl_tree_t *stream_avl,
    nvlist_t *renamed)
{
        nvlist_t *local_nv, *deleted = NULL;
        avl_tree_t *local_avl;
        nvpair_t *fselem, *nextfselem;
        char *fromsnap;
        char newname[ZFS_MAX_DATASET_NAME_LEN];
        char guidname[32];
        int error;
        boolean_t needagain, progress, recursive;
        char *s1, *s2;

        fromsnap = fnvlist_lookup_string(stream_nv, "fromsnap");

        recursive = (nvlist_lookup_boolean(stream_nv, "not_recursive") ==
            ENOENT);

        if (flags->dryrun)
                return (0);

again:
        needagain = progress = B_FALSE;

        deleted = fnvlist_alloc();

        if ((error = gather_nvlist(hdl, tofs, fromsnap, NULL,
            recursive, B_TRUE, B_FALSE, recursive, B_FALSE, B_FALSE, B_FALSE,
            B_FALSE, B_TRUE, &local_nv, &local_avl)) != 0)
                return (error);

        /*
         * Process deletes and renames
         */
        for (fselem = nvlist_next_nvpair(local_nv, NULL);
            fselem; fselem = nextfselem) {
                nvlist_t *nvfs, *snaps;
                nvlist_t *stream_nvfs = NULL;
                nvpair_t *snapelem, *nextsnapelem;
                uint64_t fromguid = 0;
                uint64_t originguid = 0;
                uint64_t stream_originguid = 0;
                uint64_t parent_fromsnap_guid, stream_parent_fromsnap_guid;
                char *fsname, *stream_fsname;

                nextfselem = nvlist_next_nvpair(local_nv, fselem);

                nvfs = fnvpair_value_nvlist(fselem);
                snaps = fnvlist_lookup_nvlist(nvfs, "snaps");
                fsname = fnvlist_lookup_string(nvfs, "name");
                parent_fromsnap_guid = fnvlist_lookup_uint64(nvfs,
                    "parentfromsnap");
                (void) nvlist_lookup_uint64(nvfs, "origin", &originguid);

                /*
                 * First find the stream's fs, so we can check for
                 * a different origin (due to "zfs promote")
                 */
                for (snapelem = nvlist_next_nvpair(snaps, NULL);
                    snapelem; snapelem = nvlist_next_nvpair(snaps, snapelem)) {
                        uint64_t thisguid;

                        thisguid = fnvpair_value_uint64(snapelem);
                        stream_nvfs = fsavl_find(stream_avl, thisguid, NULL);

                        if (stream_nvfs != NULL)
                                break;
                }

                /* check for promote */
                (void) nvlist_lookup_uint64(stream_nvfs, "origin",
                    &stream_originguid);
                if (stream_nvfs && originguid != stream_originguid) {
                        switch (created_before(hdl, local_avl,
                            stream_originguid, originguid)) {
                        case 1: {
                                /* promote it! */
                                nvlist_t *origin_nvfs;
                                char *origin_fsname;

                                origin_nvfs = fsavl_find(local_avl, originguid,
                                    NULL);
                                origin_fsname = fnvlist_lookup_string(
                                    origin_nvfs, "name");
                                error = recv_promote(hdl, fsname, origin_fsname,
                                    flags);
                                if (error == 0)
                                        progress = B_TRUE;
                                break;
                        }
                        default:
                                break;
                        case -1:
                                fsavl_destroy(local_avl);
                                fnvlist_free(local_nv);
                                return (-1);
                        }
                        /*
                         * We had/have the wrong origin, therefore our
                         * list of snapshots is wrong.  Need to handle
                         * them on the next pass.
                         */
                        needagain = B_TRUE;
                        continue;
                }

                for (snapelem = nvlist_next_nvpair(snaps, NULL);
                    snapelem; snapelem = nextsnapelem) {
                        uint64_t thisguid;
                        char *stream_snapname;
                        nvlist_t *found, *props;

                        nextsnapelem = nvlist_next_nvpair(snaps, snapelem);

                        thisguid = fnvpair_value_uint64(snapelem);
                        found = fsavl_find(stream_avl, thisguid,
                            &stream_snapname);

                        /* check for delete */
                        if (found == NULL) {
                                char name[ZFS_MAX_DATASET_NAME_LEN];

                                if (!flags->force)
                                        continue;

                                (void) snprintf(name, sizeof (name), "%s@%s",
                                    fsname, nvpair_name(snapelem));

                                error = recv_destroy(hdl, name,
                                    strlen(fsname)+1, newname, flags);
                                if (error)
                                        needagain = B_TRUE;
                                else
                                        progress = B_TRUE;
                                sprintf(guidname, "%llu",
                                    (u_longlong_t)thisguid);
                                nvlist_add_boolean(deleted, guidname);
                                continue;
                        }

                        stream_nvfs = found;

                        if (0 == nvlist_lookup_nvlist(stream_nvfs, "snapprops",
                            &props) && 0 == nvlist_lookup_nvlist(props,
                            stream_snapname, &props)) {
                                zfs_cmd_t zc = {"\0"};

                                zc.zc_cookie = B_TRUE; /* received */
                                (void) snprintf(zc.zc_name, sizeof (zc.zc_name),
                                    "%s@%s", fsname, nvpair_name(snapelem));
                                if (zcmd_write_src_nvlist(hdl, &zc,
                                    props) == 0) {
                                        (void) zfs_ioctl(hdl,
                                            ZFS_IOC_SET_PROP, &zc);
                                        zcmd_free_nvlists(&zc);
                                }
                        }

                        /* check for different snapname */
                        if (strcmp(nvpair_name(snapelem),
                            stream_snapname) != 0) {
                                char name[ZFS_MAX_DATASET_NAME_LEN];
                                char tryname[ZFS_MAX_DATASET_NAME_LEN];

                                (void) snprintf(name, sizeof (name), "%s@%s",
                                    fsname, nvpair_name(snapelem));
                                (void) snprintf(tryname, sizeof (name), "%s@%s",
                                    fsname, stream_snapname);

                                error = recv_rename(hdl, name, tryname,
                                    strlen(fsname)+1, newname, flags);
                                if (error)
                                        needagain = B_TRUE;
                                else
                                        progress = B_TRUE;
                        }

                        if (strcmp(stream_snapname, fromsnap) == 0)
                                fromguid = thisguid;
                }

                /* check for delete */
                if (stream_nvfs == NULL) {
                        if (!flags->force)
                                continue;

                        error = recv_destroy(hdl, fsname, strlen(tofs)+1,
                            newname, flags);
                        if (error)
                                needagain = B_TRUE;
                        else
                                progress = B_TRUE;
                        sprintf(guidname, "%llu",
                            (u_longlong_t)parent_fromsnap_guid);
                        nvlist_add_boolean(deleted, guidname);
                        continue;
                }

                if (fromguid == 0) {
                        if (flags->verbose) {
                                (void) printf("local fs %s does not have "
                                    "fromsnap (%s in stream); must have "
                                    "been deleted locally; ignoring\n",
                                    fsname, fromsnap);
                        }
                        continue;
                }

                stream_fsname = fnvlist_lookup_string(stream_nvfs, "name");
                stream_parent_fromsnap_guid = fnvlist_lookup_uint64(
                    stream_nvfs, "parentfromsnap");

                s1 = strrchr(fsname, '/');
                s2 = strrchr(stream_fsname, '/');

                /*
                 * Check if we're going to rename based on parent guid change
                 * and the current parent guid was also deleted. If it was then
                 * rename will fail and is likely unneeded, so avoid this and
                 * force an early retry to determine the new
                 * parent_fromsnap_guid.
                 */
                if (stream_parent_fromsnap_guid != 0 &&
                    parent_fromsnap_guid != 0 &&
                    stream_parent_fromsnap_guid != parent_fromsnap_guid) {
                        sprintf(guidname, "%llu",
                            (u_longlong_t)parent_fromsnap_guid);
                        if (nvlist_exists(deleted, guidname)) {
                                progress = B_TRUE;
                                needagain = B_TRUE;
                                goto doagain;
                        }
                }

                /*
                 * Check for rename. If the exact receive path is specified, it
                 * does not count as a rename, but we still need to check the
                 * datasets beneath it.
                 */
                if ((stream_parent_fromsnap_guid != 0 &&
                    parent_fromsnap_guid != 0 &&
                    stream_parent_fromsnap_guid != parent_fromsnap_guid) ||
                    ((flags->isprefix || strcmp(tofs, fsname) != 0) &&
                    (s1 != NULL) && (s2 != NULL) && strcmp(s1, s2) != 0)) {
                        nvlist_t *parent;
                        char tryname[ZFS_MAX_DATASET_NAME_LEN];

                        parent = fsavl_find(local_avl,
                            stream_parent_fromsnap_guid, NULL);
                        /*
                         * NB: parent might not be found if we used the
                         * tosnap for stream_parent_fromsnap_guid,
                         * because the parent is a newly-created fs;
                         * we'll be able to rename it after we recv the
                         * new fs.
                         */
                        if (parent != NULL) {
                                char *pname;

                                pname = fnvlist_lookup_string(parent, "name");
                                (void) snprintf(tryname, sizeof (tryname),
                                    "%s%s", pname, strrchr(stream_fsname, '/'));
                        } else {
                                tryname[0] = '\0';
                                if (flags->verbose) {
                                        (void) printf("local fs %s new parent "
                                            "not found\n", fsname);
                                }
                        }

                        newname[0] = '\0';

                        error = recv_rename(hdl, fsname, tryname,
                            strlen(tofs)+1, newname, flags);

                        if (renamed != NULL && newname[0] != '\0') {
                                fnvlist_add_boolean(renamed, newname);
                        }

                        if (error)
                                needagain = B_TRUE;
                        else
                                progress = B_TRUE;
                }
        }

doagain:
        fsavl_destroy(local_avl);
        fnvlist_free(local_nv);
        fnvlist_free(deleted);

        if (needagain && progress) {
                /* do another pass to fix up temporary names */
                if (flags->verbose)
                        (void) printf("another pass:\n");
                goto again;
        }

        return (needagain || error != 0);
}

static int
zfs_receive_package(libzfs_handle_t *hdl, int fd, const char *destname,
    recvflags_t *flags, dmu_replay_record_t *drr, zio_cksum_t *zc,
    char **top_zfs, nvlist_t *cmdprops)
{
        nvlist_t *stream_nv = NULL;
        avl_tree_t *stream_avl = NULL;
        char *fromsnap = NULL;
        char *sendsnap = NULL;
        char *cp;
        char tofs[ZFS_MAX_DATASET_NAME_LEN];
        char sendfs[ZFS_MAX_DATASET_NAME_LEN];
        char errbuf[1024];
        dmu_replay_record_t drre;
        int error;
        boolean_t anyerr = B_FALSE;
        boolean_t softerr = B_FALSE;
        boolean_t recursive, raw;

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot receive"));

        assert(drr->drr_type == DRR_BEGIN);
        assert(drr->drr_u.drr_begin.drr_magic == DMU_BACKUP_MAGIC);
        assert(DMU_GET_STREAM_HDRTYPE(drr->drr_u.drr_begin.drr_versioninfo) ==
            DMU_COMPOUNDSTREAM);

        /*
         * Read in the nvlist from the stream.
         */
        if (drr->drr_payloadlen != 0) {
                error = recv_read_nvlist(hdl, fd, drr->drr_payloadlen,
                    &stream_nv, flags->byteswap, zc);
                if (error) {
                        error = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        goto out;
                }
        }

        recursive = (nvlist_lookup_boolean(stream_nv, "not_recursive") ==
            ENOENT);
        raw = (nvlist_lookup_boolean(stream_nv, "raw") == 0);

        if (recursive && strchr(destname, '@')) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "cannot specify snapshot name for multi-snapshot stream"));
                error = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                goto out;
        }

        /*
         * Read in the end record and verify checksum.
         */
        if (0 != (error = recv_read(hdl, fd, &drre, sizeof (drre),
            flags->byteswap, NULL)))
                goto out;
        if (flags->byteswap) {
                drre.drr_type = BSWAP_32(drre.drr_type);
                drre.drr_u.drr_end.drr_checksum.zc_word[0] =
                    BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[0]);
                drre.drr_u.drr_end.drr_checksum.zc_word[1] =
                    BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[1]);
                drre.drr_u.drr_end.drr_checksum.zc_word[2] =
                    BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[2]);
                drre.drr_u.drr_end.drr_checksum.zc_word[3] =
                    BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[3]);
        }
        if (drre.drr_type != DRR_END) {
                error = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                goto out;
        }
        if (!ZIO_CHECKSUM_EQUAL(drre.drr_u.drr_end.drr_checksum, *zc)) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "incorrect header checksum"));
                error = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                goto out;
        }

        (void) nvlist_lookup_string(stream_nv, "fromsnap", &fromsnap);

        if (drr->drr_payloadlen != 0) {
                nvlist_t *stream_fss;

                stream_fss = fnvlist_lookup_nvlist(stream_nv, "fss");
                if ((stream_avl = fsavl_create(stream_fss)) == NULL) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "couldn't allocate avl tree"));
                        error = zfs_error(hdl, EZFS_NOMEM, errbuf);
                        goto out;
                }

                if (fromsnap != NULL && recursive) {
                        nvlist_t *renamed = NULL;
                        nvpair_t *pair = NULL;

                        (void) strlcpy(tofs, destname, sizeof (tofs));
                        if (flags->isprefix) {
                                struct drr_begin *drrb = &drr->drr_u.drr_begin;
                                int i;

                                if (flags->istail) {
                                        cp = strrchr(drrb->drr_toname, '/');
                                        if (cp == NULL) {
                                                (void) strlcat(tofs, "/",
                                                    sizeof (tofs));
                                                i = 0;
                                        } else {
                                                i = (cp - drrb->drr_toname);
                                        }
                                } else {
                                        i = strcspn(drrb->drr_toname, "/@");
                                }
                                /* zfs_receive_one() will create_parents() */
                                (void) strlcat(tofs, &drrb->drr_toname[i],
                                    sizeof (tofs));
                                *strchr(tofs, '@') = '\0';
                        }

                        if (!flags->dryrun && !flags->nomount) {
                                renamed = fnvlist_alloc();
                        }

                        softerr = recv_incremental_replication(hdl, tofs, flags,
                            stream_nv, stream_avl, renamed);

                        /* Unmount renamed filesystems before receiving. */
                        while ((pair = nvlist_next_nvpair(renamed,
                            pair)) != NULL) {
                                zfs_handle_t *zhp;
                                prop_changelist_t *clp = NULL;

                                zhp = zfs_open(hdl, nvpair_name(pair),
                                    ZFS_TYPE_FILESYSTEM);
                                if (zhp != NULL) {
                                        clp = changelist_gather(zhp,
                                            ZFS_PROP_MOUNTPOINT, 0,
                                            flags->forceunmount ? MS_FORCE : 0);
                                        zfs_close(zhp);
                                        if (clp != NULL) {
                                                softerr |=
                                                    changelist_prefix(clp);
                                                changelist_free(clp);
                                        }
                                }
                        }

                        fnvlist_free(renamed);
                }
        }

        /*
         * Get the fs specified by the first path in the stream (the top level
         * specified by 'zfs send') and pass it to each invocation of
         * zfs_receive_one().
         */
        (void) strlcpy(sendfs, drr->drr_u.drr_begin.drr_toname,
            sizeof (sendfs));
        if ((cp = strchr(sendfs, '@')) != NULL) {
                *cp = '\0';
                /*
                 * Find the "sendsnap", the final snapshot in a replication
                 * stream.  zfs_receive_one() handles certain errors
                 * differently, depending on if the contained stream is the
                 * last one or not.
                 */
                sendsnap = (cp + 1);
        }

        /* Finally, receive each contained stream */
        do {
                /*
                 * we should figure out if it has a recoverable
                 * error, in which case do a recv_skip() and drive on.
                 * Note, if we fail due to already having this guid,
                 * zfs_receive_one() will take care of it (ie,
                 * recv_skip() and return 0).
                 */
                error = zfs_receive_impl(hdl, destname, NULL, flags, fd,
                    sendfs, stream_nv, stream_avl, top_zfs, sendsnap, cmdprops);
                if (error == ENODATA) {
                        error = 0;
                        break;
                }
                anyerr |= error;
        } while (error == 0);

        if (drr->drr_payloadlen != 0 && recursive && fromsnap != NULL) {
                /*
                 * Now that we have the fs's they sent us, try the
                 * renames again.
                 */
                softerr = recv_incremental_replication(hdl, tofs, flags,
                    stream_nv, stream_avl, NULL);
        }

        if (raw && softerr == 0 && *top_zfs != NULL) {
                softerr = recv_fix_encryption_hierarchy(hdl, *top_zfs,
                    stream_nv);
        }

out:
        fsavl_destroy(stream_avl);
        fnvlist_free(stream_nv);
        if (softerr)
                error = -2;
        if (anyerr)
                error = -1;
        return (error);
}

static void
trunc_prop_errs(int truncated)
{
        ASSERT(truncated != 0);

        if (truncated == 1)
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "1 more property could not be set\n"));
        else
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "%d more properties could not be set\n"), truncated);
}

static int
recv_skip(libzfs_handle_t *hdl, int fd, boolean_t byteswap)
{
        dmu_replay_record_t *drr;
        void *buf = zfs_alloc(hdl, SPA_MAXBLOCKSIZE);
        uint64_t payload_size;
        char errbuf[1024];

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot receive"));

        /* XXX would be great to use lseek if possible... */
        drr = buf;

        while (recv_read(hdl, fd, drr, sizeof (dmu_replay_record_t),
            byteswap, NULL) == 0) {
                if (byteswap)
                        drr->drr_type = BSWAP_32(drr->drr_type);

                switch (drr->drr_type) {
                case DRR_BEGIN:
                        if (drr->drr_payloadlen != 0) {
                                (void) recv_read(hdl, fd, buf,
                                    drr->drr_payloadlen, B_FALSE, NULL);
                        }
                        break;

                case DRR_END:
                        free(buf);
                        return (0);

                case DRR_OBJECT:
                        if (byteswap) {
                                drr->drr_u.drr_object.drr_bonuslen =
                                    BSWAP_32(drr->drr_u.drr_object.
                                    drr_bonuslen);
                                drr->drr_u.drr_object.drr_raw_bonuslen =
                                    BSWAP_32(drr->drr_u.drr_object.
                                    drr_raw_bonuslen);
                        }

                        payload_size =
                            DRR_OBJECT_PAYLOAD_SIZE(&drr->drr_u.drr_object);
                        (void) recv_read(hdl, fd, buf, payload_size,
                            B_FALSE, NULL);
                        break;

                case DRR_WRITE:
                        if (byteswap) {
                                drr->drr_u.drr_write.drr_logical_size =
                                    BSWAP_64(
                                    drr->drr_u.drr_write.drr_logical_size);
                                drr->drr_u.drr_write.drr_compressed_size =
                                    BSWAP_64(
                                    drr->drr_u.drr_write.drr_compressed_size);
                        }
                        payload_size =
                            DRR_WRITE_PAYLOAD_SIZE(&drr->drr_u.drr_write);
                        assert(payload_size <= SPA_MAXBLOCKSIZE);
                        (void) recv_read(hdl, fd, buf,
                            payload_size, B_FALSE, NULL);
                        break;
                case DRR_SPILL:
                        if (byteswap) {
                                drr->drr_u.drr_spill.drr_length =
                                    BSWAP_64(drr->drr_u.drr_spill.drr_length);
                                drr->drr_u.drr_spill.drr_compressed_size =
                                    BSWAP_64(drr->drr_u.drr_spill.
                                    drr_compressed_size);
                        }

                        payload_size =
                            DRR_SPILL_PAYLOAD_SIZE(&drr->drr_u.drr_spill);
                        (void) recv_read(hdl, fd, buf, payload_size,
                            B_FALSE, NULL);
                        break;
                case DRR_WRITE_EMBEDDED:
                        if (byteswap) {
                                drr->drr_u.drr_write_embedded.drr_psize =
                                    BSWAP_32(drr->drr_u.drr_write_embedded.
                                    drr_psize);
                        }
                        (void) recv_read(hdl, fd, buf,
                            P2ROUNDUP(drr->drr_u.drr_write_embedded.drr_psize,
                            8), B_FALSE, NULL);
                        break;
                case DRR_OBJECT_RANGE:
                case DRR_WRITE_BYREF:
                case DRR_FREEOBJECTS:
                case DRR_FREE:
                        break;

                default:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "invalid record type"));
                        free(buf);
                        return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
                }
        }

        free(buf);
        return (-1);
}

static void
recv_ecksum_set_aux(libzfs_handle_t *hdl, const char *target_snap,
    boolean_t resumable, boolean_t checksum)
{
        char target_fs[ZFS_MAX_DATASET_NAME_LEN];

        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, (checksum ?
            "checksum mismatch" : "incomplete stream")));

        if (!resumable)
                return;
        (void) strlcpy(target_fs, target_snap, sizeof (target_fs));
        *strchr(target_fs, '@') = '\0';
        zfs_handle_t *zhp = zfs_open(hdl, target_fs,
            ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME);
        if (zhp == NULL)
                return;

        char token_buf[ZFS_MAXPROPLEN];
        int error = zfs_prop_get(zhp, ZFS_PROP_RECEIVE_RESUME_TOKEN,
            token_buf, sizeof (token_buf),
            NULL, NULL, 0, B_TRUE);
        if (error == 0) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "checksum mismatch or incomplete stream.\n"
                    "Partially received snapshot is saved.\n"
                    "A resuming stream can be generated on the sending "
                    "system by running:\n"
                    "    zfs send -t %s"),
                    token_buf);
        }
        zfs_close(zhp);
}

/*
 * Prepare a new nvlist of properties that are to override (-o) or be excluded
 * (-x) from the received dataset
 * recvprops: received properties from the send stream
 * cmdprops: raw input properties from command line
 * origprops: properties, both locally-set and received, currently set on the
 *            target dataset if it exists, NULL otherwise.
 * oxprops: valid output override (-o) and excluded (-x) properties
 */
static int
zfs_setup_cmdline_props(libzfs_handle_t *hdl, zfs_type_t type,
    char *fsname, boolean_t zoned, boolean_t recursive, boolean_t newfs,
    boolean_t raw, boolean_t toplevel, nvlist_t *recvprops, nvlist_t *cmdprops,
    nvlist_t *origprops, nvlist_t **oxprops, uint8_t **wkeydata_out,
    uint_t *wkeylen_out, const char *errbuf)
{
        nvpair_t *nvp;
        nvlist_t *oprops, *voprops;
        zfs_handle_t *zhp = NULL;
        zpool_handle_t *zpool_hdl = NULL;
        char *cp;
        int ret = 0;
        char namebuf[ZFS_MAX_DATASET_NAME_LEN];

        if (nvlist_empty(cmdprops))
                return (0); /* No properties to override or exclude */

        *oxprops = fnvlist_alloc();
        oprops = fnvlist_alloc();

        strlcpy(namebuf, fsname, ZFS_MAX_DATASET_NAME_LEN);

        /*
         * Get our dataset handle. The target dataset may not exist yet.
         */
        if (zfs_dataset_exists(hdl, namebuf, ZFS_TYPE_DATASET)) {
                zhp = zfs_open(hdl, namebuf, ZFS_TYPE_DATASET);
                if (zhp == NULL) {
                        ret = -1;
                        goto error;
                }
        }

        /* open the zpool handle */
        cp = strchr(namebuf, '/');
        if (cp != NULL)
                *cp = '\0';
        zpool_hdl = zpool_open(hdl, namebuf);
        if (zpool_hdl == NULL) {
                ret = -1;
                goto error;
        }

        /* restore namebuf to match fsname for later use */
        if (cp != NULL)
                *cp = '/';

        /*
         * first iteration: process excluded (-x) properties now and gather
         * added (-o) properties to be later processed by zfs_valid_proplist()
         */
        nvp = NULL;
        while ((nvp = nvlist_next_nvpair(cmdprops, nvp)) != NULL) {
                const char *name = nvpair_name(nvp);
                zfs_prop_t prop = zfs_name_to_prop(name);

                /*
                 * It turns out, if we don't normalize "aliased" names
                 * e.g. compress= against the "real" names (e.g. compression)
                 * here, then setting/excluding them does not work as
                 * intended.
                 *
                 * But since user-defined properties wouldn't have a valid
                 * mapping here, we do this conditional dance.
                 */
                const char *newname = name;
                if (prop >= ZFS_PROP_TYPE)
                        newname = zfs_prop_to_name(prop);

                /* "origin" is processed separately, don't handle it here */
                if (prop == ZFS_PROP_ORIGIN)
                        continue;

                /* raw streams can't override encryption properties */
                if ((zfs_prop_encryption_key_param(prop) ||
                    prop == ZFS_PROP_ENCRYPTION) && raw) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "encryption property '%s' cannot "
                            "be set or excluded for raw streams."), name);
                        ret = zfs_error(hdl, EZFS_BADPROP, errbuf);
                        goto error;
                }

                /* incremental streams can only exclude encryption properties */
                if ((zfs_prop_encryption_key_param(prop) ||
                    prop == ZFS_PROP_ENCRYPTION) && !newfs &&
                    nvpair_type(nvp) != DATA_TYPE_BOOLEAN) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "encryption property '%s' cannot "
                            "be set for incremental streams."), name);
                        ret = zfs_error(hdl, EZFS_BADPROP, errbuf);
                        goto error;
                }

                switch (nvpair_type(nvp)) {
                case DATA_TYPE_BOOLEAN: /* -x property */
                        /*
                         * DATA_TYPE_BOOLEAN is the way we're asked to "exclude"
                         * a property: this is done by forcing an explicit
                         * inherit on the destination so the effective value is
                         * not the one we received from the send stream.
                         */
                        if (!zfs_prop_valid_for_type(prop, type, B_FALSE) &&
                            !zfs_prop_user(name)) {
                                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                                    "Warning: %s: property '%s' does not "
                                    "apply to datasets of this type\n"),
                                    fsname, name);
                                continue;
                        }
                        /*
                         * We do this only if the property is not already
                         * locally-set, in which case its value will take
                         * priority over the received anyway.
                         */
                        if (nvlist_exists(origprops, newname)) {
                                nvlist_t *attrs;
                                char *source = NULL;

                                attrs = fnvlist_lookup_nvlist(origprops,
                                    newname);
                                if (nvlist_lookup_string(attrs,
                                    ZPROP_SOURCE, &source) == 0 &&
                                    strcmp(source, ZPROP_SOURCE_VAL_RECVD) != 0)
                                        continue;
                        }
                        /*
                         * We can't force an explicit inherit on non-inheritable
                         * properties: if we're asked to exclude this kind of
                         * values we remove them from "recvprops" input nvlist.
                         */
                        if (!zfs_prop_user(name) && /* can be inherited too */
                            !zfs_prop_inheritable(prop) &&
                            nvlist_exists(recvprops, newname))
                                fnvlist_remove(recvprops, newname);
                        else
                                fnvlist_add_boolean(*oxprops, newname);
                        break;
                case DATA_TYPE_STRING: /* -o property=value */
                        /*
                         * we're trying to override a property that does not
                         * make sense for this type of dataset, but we don't
                         * want to fail if the receive is recursive: this comes
                         * in handy when the send stream contains, for
                         * instance, a child ZVOL and we're trying to receive
                         * it with "-o atime=on"
                         */
                        if (!zfs_prop_valid_for_type(prop, type, B_FALSE) &&
                            !zfs_prop_user(name)) {
                                if (recursive)
                                        continue;
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "property '%s' does not apply to datasets "
                                    "of this type"), name);
                                ret = zfs_error(hdl, EZFS_BADPROP, errbuf);
                                goto error;
                        }
                        fnvlist_add_string(oprops, newname,
                            fnvpair_value_string(nvp));
                        break;
                default:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "property '%s' must be a string or boolean"), name);
                        ret = zfs_error(hdl, EZFS_BADPROP, errbuf);
                        goto error;
                }
        }

        if (toplevel) {
                /* convert override strings properties to native */
                if ((voprops = zfs_valid_proplist(hdl, ZFS_TYPE_DATASET,
                    oprops, zoned, zhp, zpool_hdl, B_FALSE, errbuf)) == NULL) {
                        ret = zfs_error(hdl, EZFS_BADPROP, errbuf);
                        goto error;
                }

                /*
                 * zfs_crypto_create() requires the parent name. Get it
                 * by truncating the fsname copy stored in namebuf.
                 */
                cp = strrchr(namebuf, '/');
                if (cp != NULL)
                        *cp = '\0';

                if (!raw && zfs_crypto_create(hdl, namebuf, voprops, NULL,
                    B_FALSE, wkeydata_out, wkeylen_out) != 0) {
                        fnvlist_free(voprops);
                        ret = zfs_error(hdl, EZFS_CRYPTOFAILED, errbuf);
                        goto error;
                }

                /* second pass: process "-o" properties */
                fnvlist_merge(*oxprops, voprops);
                fnvlist_free(voprops);
        } else {
                /* override props on child dataset are inherited */
                nvp = NULL;
                while ((nvp = nvlist_next_nvpair(oprops, nvp)) != NULL) {
                        const char *name = nvpair_name(nvp);
                        fnvlist_add_boolean(*oxprops, name);
                }
        }

error:
        if (zhp != NULL)
                zfs_close(zhp);
        if (zpool_hdl != NULL)
                zpool_close(zpool_hdl);
        fnvlist_free(oprops);
        return (ret);
}

/*
 * Restores a backup of tosnap from the file descriptor specified by infd.
 */
static int
zfs_receive_one(libzfs_handle_t *hdl, int infd, const char *tosnap,
    const char *originsnap, recvflags_t *flags, dmu_replay_record_t *drr,
    dmu_replay_record_t *drr_noswap, const char *sendfs, nvlist_t *stream_nv,
    avl_tree_t *stream_avl, char **top_zfs,
    const char *finalsnap, nvlist_t *cmdprops)
{
        struct timespec begin_time;
        int ioctl_err, ioctl_errno, err;
        char *cp;
        struct drr_begin *drrb = &drr->drr_u.drr_begin;
        char errbuf[1024];
        const char *chopprefix;
        boolean_t newfs = B_FALSE;
        boolean_t stream_wantsnewfs, stream_resumingnewfs;
        boolean_t newprops = B_FALSE;
        uint64_t read_bytes = 0;
        uint64_t errflags = 0;
        uint64_t parent_snapguid = 0;
        prop_changelist_t *clp = NULL;
        nvlist_t *snapprops_nvlist = NULL;
        nvlist_t *snapholds_nvlist = NULL;
        zprop_errflags_t prop_errflags;
        nvlist_t *prop_errors = NULL;
        boolean_t recursive;
        char *snapname = NULL;
        char destsnap[MAXPATHLEN * 2];
        char origin[MAXNAMELEN] = {0};
        char name[MAXPATHLEN];
        char tmp_keylocation[MAXNAMELEN] = {0};
        nvlist_t *rcvprops = NULL; /* props received from the send stream */
        nvlist_t *oxprops = NULL; /* override (-o) and exclude (-x) props */
        nvlist_t *origprops = NULL; /* original props (if destination exists) */
        zfs_type_t type = ZFS_TYPE_INVALID;
        boolean_t toplevel = B_FALSE;
        boolean_t zoned = B_FALSE;
        boolean_t hastoken = B_FALSE;
        boolean_t redacted;
        uint8_t *wkeydata = NULL;
        uint_t wkeylen = 0;

#ifndef CLOCK_MONOTONIC_RAW
#define CLOCK_MONOTONIC_RAW CLOCK_MONOTONIC
#endif
        clock_gettime(CLOCK_MONOTONIC_RAW, &begin_time);

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot receive"));

        recursive = (nvlist_lookup_boolean(stream_nv, "not_recursive") ==
            ENOENT);

        /* Did the user request holds be skipped via zfs recv -k? */
        boolean_t holds = flags->holds && !flags->skipholds;

        if (stream_avl != NULL) {
                char *keylocation = NULL;
                nvlist_t *lookup = NULL;
                nvlist_t *fs = fsavl_find(stream_avl, drrb->drr_toguid,
                    &snapname);

                (void) nvlist_lookup_uint64(fs, "parentfromsnap",
                    &parent_snapguid);
                err = nvlist_lookup_nvlist(fs, "props", &rcvprops);
                if (err) {
                        rcvprops = fnvlist_alloc();
                        newprops = B_TRUE;
                }

                /*
                 * The keylocation property may only be set on encryption roots,
                 * but this dataset might not become an encryption root until
                 * recv_fix_encryption_hierarchy() is called. That function
                 * will fixup the keylocation anyway, so we temporarily unset
                 * the keylocation for now to avoid any errors from the receive
                 * ioctl.
                 */
                err = nvlist_lookup_string(rcvprops,
                    zfs_prop_to_name(ZFS_PROP_KEYLOCATION), &keylocation);
                if (err == 0) {
                        strcpy(tmp_keylocation, keylocation);
                        (void) nvlist_remove_all(rcvprops,
                            zfs_prop_to_name(ZFS_PROP_KEYLOCATION));
                }

                if (flags->canmountoff) {
                        fnvlist_add_uint64(rcvprops,
                            zfs_prop_to_name(ZFS_PROP_CANMOUNT), 0);
                } else if (newprops) {  /* nothing in rcvprops, eliminate it */
                        fnvlist_free(rcvprops);
                        rcvprops = NULL;
                        newprops = B_FALSE;
                }
                if (0 == nvlist_lookup_nvlist(fs, "snapprops", &lookup)) {
                        snapprops_nvlist = fnvlist_lookup_nvlist(lookup,
                            snapname);
                }
                if (holds) {
                        if (0 == nvlist_lookup_nvlist(fs, "snapholds",
                            &lookup)) {
                                snapholds_nvlist = fnvlist_lookup_nvlist(
                                    lookup, snapname);
                        }
                }
        }

        cp = NULL;

        /*
         * Determine how much of the snapshot name stored in the stream
         * we are going to tack on to the name they specified on the
         * command line, and how much we are going to chop off.
         *
         * If they specified a snapshot, chop the entire name stored in
         * the stream.
         */
        if (flags->istail) {
                /*
                 * A filesystem was specified with -e. We want to tack on only
                 * the tail of the sent snapshot path.
                 */
                if (strchr(tosnap, '@')) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                            "argument - snapshot not allowed with -e"));
                        err = zfs_error(hdl, EZFS_INVALIDNAME, errbuf);
                        goto out;
                }

                chopprefix = strrchr(sendfs, '/');

                if (chopprefix == NULL) {
                        /*
                         * The tail is the poolname, so we need to
                         * prepend a path separator.
                         */
                        int len = strlen(drrb->drr_toname);
                        cp = malloc(len + 2);
                        cp[0] = '/';
                        (void) strcpy(&cp[1], drrb->drr_toname);
                        chopprefix = cp;
                } else {
                        chopprefix = drrb->drr_toname + (chopprefix - sendfs);
                }
        } else if (flags->isprefix) {
                /*
                 * A filesystem was specified with -d. We want to tack on
                 * everything but the first element of the sent snapshot path
                 * (all but the pool name).
                 */
                if (strchr(tosnap, '@')) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                            "argument - snapshot not allowed with -d"));
                        err = zfs_error(hdl, EZFS_INVALIDNAME, errbuf);
                        goto out;
                }

                chopprefix = strchr(drrb->drr_toname, '/');
                if (chopprefix == NULL)
                        chopprefix = strchr(drrb->drr_toname, '@');
        } else if (strchr(tosnap, '@') == NULL) {
                /*
                 * If a filesystem was specified without -d or -e, we want to
                 * tack on everything after the fs specified by 'zfs send'.
                 */
                chopprefix = drrb->drr_toname + strlen(sendfs);
        } else {
                /* A snapshot was specified as an exact path (no -d or -e). */
                if (recursive) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "cannot specify snapshot name for multi-snapshot "
                            "stream"));
                        err = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        goto out;
                }
                chopprefix = drrb->drr_toname + strlen(drrb->drr_toname);
        }

        ASSERT(strstr(drrb->drr_toname, sendfs) == drrb->drr_toname);
        ASSERT(chopprefix > drrb->drr_toname || strchr(sendfs, '/') == NULL);
        ASSERT(chopprefix <= drrb->drr_toname + strlen(drrb->drr_toname) ||
            strchr(sendfs, '/') == NULL);
        ASSERT(chopprefix[0] == '/' || chopprefix[0] == '@' ||
            chopprefix[0] == '\0');

        /*
         * Determine name of destination snapshot.
         */
        (void) strlcpy(destsnap, tosnap, sizeof (destsnap));
        (void) strlcat(destsnap, chopprefix, sizeof (destsnap));
        free(cp);
        if (!zfs_name_valid(destsnap, ZFS_TYPE_SNAPSHOT)) {
                err = zfs_error(hdl, EZFS_INVALIDNAME, errbuf);
                goto out;
        }

        /*
         * Determine the name of the origin snapshot.
         */
        if (originsnap) {
                (void) strlcpy(origin, originsnap, sizeof (origin));
                if (flags->verbose)
                        (void) printf("using provided clone origin %s\n",
                            origin);
        } else if (drrb->drr_flags & DRR_FLAG_CLONE) {
                if (guid_to_name(hdl, destsnap,
                    drrb->drr_fromguid, B_FALSE, origin) != 0) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "local origin for clone %s does not exist"),
                            destsnap);
                        err = zfs_error(hdl, EZFS_NOENT, errbuf);
                        goto out;
                }
                if (flags->verbose)
                        (void) printf("found clone origin %s\n", origin);
        }

        if ((DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo) &
            DMU_BACKUP_FEATURE_DEDUP)) {
                (void) fprintf(stderr,
                    gettext("ERROR: \"zfs receive\" no longer supports "
                    "deduplicated send streams.  Use\n"
                    "the \"zstream redup\" command to convert this stream "
                    "to a regular,\n"
                    "non-deduplicated stream.\n"));
                err = zfs_error(hdl, EZFS_NOTSUP, errbuf);
                goto out;
        }

        boolean_t resuming = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo) &
            DMU_BACKUP_FEATURE_RESUMING;
        boolean_t raw = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo) &
            DMU_BACKUP_FEATURE_RAW;
        boolean_t embedded = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo) &
            DMU_BACKUP_FEATURE_EMBED_DATA;
        stream_wantsnewfs = (drrb->drr_fromguid == 0 ||
            (drrb->drr_flags & DRR_FLAG_CLONE) || originsnap) && !resuming;
        stream_resumingnewfs = (drrb->drr_fromguid == 0 ||
            (drrb->drr_flags & DRR_FLAG_CLONE) || originsnap) && resuming;

        if (stream_wantsnewfs) {
                /*
                 * if the parent fs does not exist, look for it based on
                 * the parent snap GUID
                 */
                (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
                    "cannot receive new filesystem stream"));

                (void) strcpy(name, destsnap);
                cp = strrchr(name, '/');
                if (cp)
                        *cp = '\0';
                if (cp &&
                    !zfs_dataset_exists(hdl, name, ZFS_TYPE_DATASET)) {
                        char suffix[ZFS_MAX_DATASET_NAME_LEN];
                        (void) strcpy(suffix, strrchr(destsnap, '/'));
                        if (guid_to_name(hdl, name, parent_snapguid,
                            B_FALSE, destsnap) == 0) {
                                *strchr(destsnap, '@') = '\0';
                                (void) strcat(destsnap, suffix);
                        }
                }
        } else {
                /*
                 * If the fs does not exist, look for it based on the
                 * fromsnap GUID.
                 */
                if (resuming) {
                        (void) snprintf(errbuf, sizeof (errbuf),
                            dgettext(TEXT_DOMAIN,
                            "cannot receive resume stream"));
                } else {
                        (void) snprintf(errbuf, sizeof (errbuf),
                            dgettext(TEXT_DOMAIN,
                            "cannot receive incremental stream"));
                }

                (void) strcpy(name, destsnap);
                *strchr(name, '@') = '\0';

                /*
                 * If the exact receive path was specified and this is the
                 * topmost path in the stream, then if the fs does not exist we
                 * should look no further.
                 */
                if ((flags->isprefix || (*(chopprefix = drrb->drr_toname +
                    strlen(sendfs)) != '\0' && *chopprefix != '@')) &&
                    !zfs_dataset_exists(hdl, name, ZFS_TYPE_DATASET)) {
                        char snap[ZFS_MAX_DATASET_NAME_LEN];
                        (void) strcpy(snap, strchr(destsnap, '@'));
                        if (guid_to_name(hdl, name, drrb->drr_fromguid,
                            B_FALSE, destsnap) == 0) {
                                *strchr(destsnap, '@') = '\0';
                                (void) strcat(destsnap, snap);
                        }
                }
        }

        (void) strcpy(name, destsnap);
        *strchr(name, '@') = '\0';

        redacted = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo) &
            DMU_BACKUP_FEATURE_REDACTED;

        if (zfs_dataset_exists(hdl, name, ZFS_TYPE_DATASET)) {
                zfs_cmd_t zc = {"\0"};
                zfs_handle_t *zhp;
                boolean_t encrypted;

                (void) strcpy(zc.zc_name, name);

                /*
                 * Destination fs exists.  It must be one of these cases:
                 *  - an incremental send stream
                 *  - the stream specifies a new fs (full stream or clone)
                 *    and they want us to blow away the existing fs (and
                 *    have therefore specified -F and removed any snapshots)
                 *  - we are resuming a failed receive.
                 */
                if (stream_wantsnewfs) {
                        boolean_t is_volume = drrb->drr_type == DMU_OST_ZVOL;
                        if (!flags->force) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "destination '%s' exists\n"
                                    "must specify -F to overwrite it"), name);
                                err = zfs_error(hdl, EZFS_EXISTS, errbuf);
                                goto out;
                        }
                        if (zfs_ioctl(hdl, ZFS_IOC_SNAPSHOT_LIST_NEXT,
                            &zc) == 0) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "destination has snapshots (eg. %s)\n"
                                    "must destroy them to overwrite it"),
                                    zc.zc_name);
                                err = zfs_error(hdl, EZFS_EXISTS, errbuf);
                                goto out;
                        }
                        if (is_volume && strrchr(name, '/') == NULL) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "destination %s is the root dataset\n"
                                    "cannot overwrite with a ZVOL"),
                                    name);
                                err = zfs_error(hdl, EZFS_EXISTS, errbuf);
                                goto out;
                        }
                        if (is_volume &&
                            zfs_ioctl(hdl, ZFS_IOC_DATASET_LIST_NEXT,
                            &zc) == 0) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "destination has children (eg. %s)\n"
                                    "cannot overwrite with a ZVOL"),
                                    zc.zc_name);
                                err = zfs_error(hdl, EZFS_WRONG_PARENT, errbuf);
                                goto out;
                        }
                }

                if ((zhp = zfs_open(hdl, name,
                    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME)) == NULL) {
                        err = -1;
                        goto out;
                }

                if (stream_wantsnewfs &&
                    zhp->zfs_dmustats.dds_origin[0]) {
                        zfs_close(zhp);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "destination '%s' is a clone\n"
                            "must destroy it to overwrite it"), name);
                        err = zfs_error(hdl, EZFS_EXISTS, errbuf);
                        goto out;
                }

                /*
                 * Raw sends can not be performed as an incremental on top
                 * of existing unencrypted datasets. zfs recv -F can't be
                 * used to blow away an existing encrypted filesystem. This
                 * is because it would require the dsl dir to point to the
                 * new key (or lack of a key) and the old key at the same
                 * time. The -F flag may still be used for deleting
                 * intermediate snapshots that would otherwise prevent the
                 * receive from working.
                 */
                encrypted = zfs_prop_get_int(zhp, ZFS_PROP_ENCRYPTION) !=
                    ZIO_CRYPT_OFF;
                if (!stream_wantsnewfs && !encrypted && raw) {
                        zfs_close(zhp);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "cannot perform raw receive on top of "
                            "existing unencrypted dataset"));
                        err = zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                        goto out;
                }

                if (stream_wantsnewfs && flags->force &&
                    ((raw && !encrypted) || encrypted)) {
                        zfs_close(zhp);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "zfs receive -F cannot be used to destroy an "
                            "encrypted filesystem or overwrite an "
                            "unencrypted one with an encrypted one"));
                        err = zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                        goto out;
                }

                if (!flags->dryrun && zhp->zfs_type == ZFS_TYPE_FILESYSTEM &&
                    (stream_wantsnewfs || stream_resumingnewfs)) {
                        /* We can't do online recv in this case */
                        clp = changelist_gather(zhp, ZFS_PROP_NAME, 0,
                            flags->forceunmount ? MS_FORCE : 0);
                        if (clp == NULL) {
                                zfs_close(zhp);
                                err = -1;
                                goto out;
                        }
                        if (changelist_prefix(clp) != 0) {
                                changelist_free(clp);
                                zfs_close(zhp);
                                err = -1;
                                goto out;
                        }
                }

                /*
                 * If we are resuming a newfs, set newfs here so that we will
                 * mount it if the recv succeeds this time.  We can tell
                 * that it was a newfs on the first recv because the fs
                 * itself will be inconsistent (if the fs existed when we
                 * did the first recv, we would have received it into
                 * .../%recv).
                 */
                if (resuming && zfs_prop_get_int(zhp, ZFS_PROP_INCONSISTENT))
                        newfs = B_TRUE;

                /* we want to know if we're zoned when validating -o|-x props */
                zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);

                /* may need this info later, get it now we have zhp around */
                if (zfs_prop_get(zhp, ZFS_PROP_RECEIVE_RESUME_TOKEN, NULL, 0,
                    NULL, NULL, 0, B_TRUE) == 0)
                        hastoken = B_TRUE;

                /* gather existing properties on destination */
                origprops = fnvlist_alloc();
                fnvlist_merge(origprops, zhp->zfs_props);
                fnvlist_merge(origprops, zhp->zfs_user_props);

                zfs_close(zhp);
        } else {
                zfs_handle_t *zhp;

                /*
                 * Destination filesystem does not exist.  Therefore we better
                 * be creating a new filesystem (either from a full backup, or
                 * a clone).  It would therefore be invalid if the user
                 * specified only the pool name (i.e. if the destination name
                 * contained no slash character).
                 */
                cp = strrchr(name, '/');

                if (!stream_wantsnewfs || cp == NULL) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "destination '%s' does not exist"), name);
                        err = zfs_error(hdl, EZFS_NOENT, errbuf);
                        goto out;
                }

                /*
                 * Trim off the final dataset component so we perform the
                 * recvbackup ioctl to the filesystems's parent.
                 */
                *cp = '\0';

                if (flags->isprefix && !flags->istail && !flags->dryrun &&
                    create_parents(hdl, destsnap, strlen(tosnap)) != 0) {
                        err = zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                        goto out;
                }

                /* validate parent */
                zhp = zfs_open(hdl, name, ZFS_TYPE_DATASET);
                if (zhp == NULL) {
                        err = zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                        goto out;
                }
                if (zfs_get_type(zhp) != ZFS_TYPE_FILESYSTEM) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "parent '%s' is not a filesystem"), name);
                        err = zfs_error(hdl, EZFS_WRONG_PARENT, errbuf);
                        zfs_close(zhp);
                        goto out;
                }

                zfs_close(zhp);

                newfs = B_TRUE;
                *cp = '/';
        }

        if (flags->verbose) {
                (void) printf("%s %s stream of %s into %s\n",
                    flags->dryrun ? "would receive" : "receiving",
                    drrb->drr_fromguid ? "incremental" : "full",
                    drrb->drr_toname, destsnap);
                (void) fflush(stdout);
        }

        /*
         * If this is the top-level dataset, record it so we can use it
         * for recursive operations later.
         */
        if (top_zfs != NULL &&
            (*top_zfs == NULL || strcmp(*top_zfs, name) == 0)) {
                toplevel = B_TRUE;
                if (*top_zfs == NULL)
                        *top_zfs = zfs_strdup(hdl, name);
        }

        if (drrb->drr_type == DMU_OST_ZVOL) {
                type = ZFS_TYPE_VOLUME;
        } else if (drrb->drr_type == DMU_OST_ZFS) {
                type = ZFS_TYPE_FILESYSTEM;
        } else {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                    "invalid record type: 0x%d"), drrb->drr_type);
                err = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                goto out;
        }
        if ((err = zfs_setup_cmdline_props(hdl, type, name, zoned, recursive,
            stream_wantsnewfs, raw, toplevel, rcvprops, cmdprops, origprops,
            &oxprops, &wkeydata, &wkeylen, errbuf)) != 0)
                goto out;

        /*
         * When sending with properties (zfs send -p), the encryption property
         * is not included because it is a SETONCE property and therefore
         * treated as read only. However, we are always able to determine its
         * value because raw sends will include it in the DRR_BDEGIN payload
         * and non-raw sends with properties are not allowed for encrypted
         * datasets. Therefore, if this is a non-raw properties stream, we can
         * infer that the value should be ZIO_CRYPT_OFF and manually add that
         * to the received properties.
         */
        if (stream_wantsnewfs && !raw && rcvprops != NULL &&
            !nvlist_exists(cmdprops, zfs_prop_to_name(ZFS_PROP_ENCRYPTION))) {
                if (oxprops == NULL)
                        oxprops = fnvlist_alloc();
                fnvlist_add_uint64(oxprops,
                    zfs_prop_to_name(ZFS_PROP_ENCRYPTION), ZIO_CRYPT_OFF);
        }

        if (flags->dryrun) {
                void *buf = zfs_alloc(hdl, SPA_MAXBLOCKSIZE);

                /*
                 * We have read the DRR_BEGIN record, but we have
                 * not yet read the payload. For non-dryrun sends
                 * this will be done by the kernel, so we must
                 * emulate that here, before attempting to read
                 * more records.
                 */
                err = recv_read(hdl, infd, buf, drr->drr_payloadlen,
                    flags->byteswap, NULL);
                free(buf);
                if (err != 0)
                        goto out;

                err = recv_skip(hdl, infd, flags->byteswap);
                goto out;
        }

        err = ioctl_err = lzc_receive_with_cmdprops(destsnap, rcvprops,
            oxprops, wkeydata, wkeylen, origin, flags->force, flags->resumable,
            raw, infd, drr_noswap, -1, &read_bytes, &errflags,
            NULL, &prop_errors);
        ioctl_errno = ioctl_err;
        prop_errflags = errflags;

        if (err == 0) {
                nvpair_t *prop_err = NULL;

                while ((prop_err = nvlist_next_nvpair(prop_errors,
                    prop_err)) != NULL) {
                        char tbuf[1024];
                        zfs_prop_t prop;
                        int intval;

                        prop = zfs_name_to_prop(nvpair_name(prop_err));
                        (void) nvpair_value_int32(prop_err, &intval);
                        if (strcmp(nvpair_name(prop_err),
                            ZPROP_N_MORE_ERRORS) == 0) {
                                trunc_prop_errs(intval);
                                break;
                        } else if (snapname == NULL || finalsnap == NULL ||
                            strcmp(finalsnap, snapname) == 0 ||
                            strcmp(nvpair_name(prop_err),
                            zfs_prop_to_name(ZFS_PROP_REFQUOTA)) != 0) {
                                /*
                                 * Skip the special case of, for example,
                                 * "refquota", errors on intermediate
                                 * snapshots leading up to a final one.
                                 * That's why we have all of the checks above.
                                 *
                                 * See zfs_ioctl.c's extract_delay_props() for
                                 * a list of props which can fail on
                                 * intermediate snapshots, but shouldn't
                                 * affect the overall receive.
                                 */
                                (void) snprintf(tbuf, sizeof (tbuf),
                                    dgettext(TEXT_DOMAIN,
                                    "cannot receive %s property on %s"),
                                    nvpair_name(prop_err), name);
                                zfs_setprop_error(hdl, prop, intval, tbuf);
                        }
                }
        }

        if (err == 0 && snapprops_nvlist) {
                zfs_cmd_t zc = {"\0"};

                (void) strcpy(zc.zc_name, destsnap);
                zc.zc_cookie = B_TRUE; /* received */
                if (zcmd_write_src_nvlist(hdl, &zc, snapprops_nvlist) == 0) {
                        (void) zfs_ioctl(hdl, ZFS_IOC_SET_PROP, &zc);
                        zcmd_free_nvlists(&zc);
                }
        }
        if (err == 0 && snapholds_nvlist) {
                nvpair_t *pair;
                nvlist_t *holds, *errors = NULL;
                int cleanup_fd = -1;

                VERIFY(0 == nvlist_alloc(&holds, 0, KM_SLEEP));
                for (pair = nvlist_next_nvpair(snapholds_nvlist, NULL);
                    pair != NULL;
                    pair = nvlist_next_nvpair(snapholds_nvlist, pair)) {
                        fnvlist_add_string(holds, destsnap, nvpair_name(pair));
                }
                (void) lzc_hold(holds, cleanup_fd, &errors);
                fnvlist_free(snapholds_nvlist);
                fnvlist_free(holds);
        }

        if (err && (ioctl_errno == ENOENT || ioctl_errno == EEXIST)) {
                /*
                 * It may be that this snapshot already exists,
                 * in which case we want to consume & ignore it
                 * rather than failing.
                 */
                avl_tree_t *local_avl;
                nvlist_t *local_nv, *fs;
                cp = strchr(destsnap, '@');

                /*
                 * XXX Do this faster by just iterating over snaps in
                 * this fs.  Also if zc_value does not exist, we will
                 * get a strange "does not exist" error message.
                 */
                *cp = '\0';
                if (gather_nvlist(hdl, destsnap, NULL, NULL, B_FALSE, B_TRUE,
                    B_FALSE, B_FALSE, B_FALSE, B_FALSE, B_FALSE, B_FALSE,
                    B_TRUE, &local_nv, &local_avl) == 0) {
                        *cp = '@';
                        fs = fsavl_find(local_avl, drrb->drr_toguid, NULL);
                        fsavl_destroy(local_avl);
                        fnvlist_free(local_nv);

                        if (fs != NULL) {
                                if (flags->verbose) {
                                        (void) printf("snap %s already exists; "
                                            "ignoring\n", destsnap);
                                }
                                err = ioctl_err = recv_skip(hdl, infd,
                                    flags->byteswap);
                        }
                }
                *cp = '@';
        }

        if (ioctl_err != 0) {
                switch (ioctl_errno) {
                case ENODEV:
                        cp = strchr(destsnap, '@');
                        *cp = '\0';
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "most recent snapshot of %s does not\n"
                            "match incremental source"), destsnap);
                        (void) zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                        *cp = '@';
                        break;
                case ETXTBSY:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "destination %s has been modified\n"
                            "since most recent snapshot"), name);
                        (void) zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                        break;
                case EACCES:
                        if (raw && stream_wantsnewfs) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "failed to create encryption key"));
                        } else if (raw && !stream_wantsnewfs) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "encryption key does not match "
                                    "existing key"));
                        } else {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "inherited key must be loaded"));
                        }
                        (void) zfs_error(hdl, EZFS_CRYPTOFAILED, errbuf);
                        break;
                case EEXIST:
                        cp = strchr(destsnap, '@');
                        if (newfs) {
                                /* it's the containing fs that exists */
                                *cp = '\0';
                        }
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "destination already exists"));
                        (void) zfs_error_fmt(hdl, EZFS_EXISTS,
                            dgettext(TEXT_DOMAIN, "cannot restore to %s"),
                            destsnap);
                        *cp = '@';
                        break;
                case EINVAL:
                        if (flags->resumable) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "kernel modules must be upgraded to "
                                    "receive this stream."));
                        } else if (embedded && !raw) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "incompatible embedded data stream "
                                    "feature with encrypted receive."));
                        }
                        (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        break;
                case ECKSUM:
                case ZFS_ERR_STREAM_TRUNCATED:
                        recv_ecksum_set_aux(hdl, destsnap, flags->resumable,
                            ioctl_err == ECKSUM);
                        (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        break;
                case ZFS_ERR_STREAM_LARGE_BLOCK_MISMATCH:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "incremental send stream requires -L "
                            "(--large-block), to match previous receive."));
                        (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        break;
                case ENOTSUP:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "pool must be upgraded to receive this stream."));
                        (void) zfs_error(hdl, EZFS_BADVERSION, errbuf);
                        break;
                case EDQUOT:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "destination %s space quota exceeded."), name);
                        (void) zfs_error(hdl, EZFS_NOSPC, errbuf);
                        break;
                case ZFS_ERR_FROM_IVSET_GUID_MISSING:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "IV set guid missing. See errata %u at "
                            "https://openzfs.github.io/openzfs-docs/msg/"
                            "ZFS-8000-ER."),
                            ZPOOL_ERRATA_ZOL_8308_ENCRYPTION);
                        (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        break;
                case ZFS_ERR_FROM_IVSET_GUID_MISMATCH:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "IV set guid mismatch. See the 'zfs receive' "
                            "man page section\n discussing the limitations "
                            "of raw encrypted send streams."));
                        (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        break;
                case ZFS_ERR_SPILL_BLOCK_FLAG_MISSING:
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "Spill block flag missing for raw send.\n"
                            "The zfs software on the sending system must "
                            "be updated."));
                        (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                        break;
                case EBUSY:
                        if (hastoken) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "destination %s contains "
                                    "partially-complete state from "
                                    "\"zfs receive -s\"."), name);
                                (void) zfs_error(hdl, EZFS_BUSY, errbuf);
                                break;
                        }
                        zfs_fallthrough;
                default:
                        (void) zfs_standard_error(hdl, ioctl_errno, errbuf);
                }
        }

        /*
         * Mount the target filesystem (if created).  Also mount any
         * children of the target filesystem if we did a replication
         * receive (indicated by stream_avl being non-NULL).
         */
        if (clp) {
                if (!flags->nomount)
                        err |= changelist_postfix(clp);
                changelist_free(clp);
        }

        if ((newfs || stream_avl) && type == ZFS_TYPE_FILESYSTEM && !redacted)
                flags->domount = B_TRUE;

        if (prop_errflags & ZPROP_ERR_NOCLEAR) {
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN, "Warning: "
                    "failed to clear unreceived properties on %s"), name);
                (void) fprintf(stderr, "\n");
        }
        if (prop_errflags & ZPROP_ERR_NORESTORE) {
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN, "Warning: "
                    "failed to restore original properties on %s"), name);
                (void) fprintf(stderr, "\n");
        }

        if (err || ioctl_err) {
                err = -1;
                goto out;
        }

        if (flags->verbose) {
                char buf1[64];
                char buf2[64];
                uint64_t bytes = read_bytes;
                struct timespec delta;
                clock_gettime(CLOCK_MONOTONIC_RAW, &delta);
                if (begin_time.tv_nsec > delta.tv_nsec) {
                        delta.tv_nsec =
                            1000000000 + delta.tv_nsec - begin_time.tv_nsec;
                        delta.tv_sec -= 1;
                } else
                        delta.tv_nsec -= begin_time.tv_nsec;
                delta.tv_sec -= begin_time.tv_sec;
                if (delta.tv_sec == 0 && delta.tv_nsec == 0)
                        delta.tv_nsec = 1;
                double delta_f = delta.tv_sec + (delta.tv_nsec / 1e9);
                zfs_nicebytes(bytes, buf1, sizeof (buf1));
                zfs_nicebytes(bytes / delta_f, buf2, sizeof (buf2));

                (void) printf("received %s stream in %.2f seconds (%s/sec)\n",
                    buf1, delta_f, buf2);
        }

        err = 0;
out:
        if (prop_errors != NULL)
                fnvlist_free(prop_errors);

        if (tmp_keylocation[0] != '\0') {
                fnvlist_add_string(rcvprops,
                    zfs_prop_to_name(ZFS_PROP_KEYLOCATION), tmp_keylocation);
        }

        if (newprops)
                fnvlist_free(rcvprops);

        fnvlist_free(oxprops);
        fnvlist_free(origprops);

        return (err);
}

/*
 * Check properties we were asked to override (both -o|-x)
 */
static boolean_t
zfs_receive_checkprops(libzfs_handle_t *hdl, nvlist_t *props,
    const char *errbuf)
{
        nvpair_t *nvp = NULL;
        zfs_prop_t prop;
        const char *name;

        while ((nvp = nvlist_next_nvpair(props, nvp)) != NULL) {
                name = nvpair_name(nvp);
                prop = zfs_name_to_prop(name);

                if (prop == ZPROP_INVAL) {
                        if (!zfs_prop_user(name)) {
                                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                    "%s: invalid property '%s'"), errbuf, name);
                                return (B_FALSE);
                        }
                        continue;
                }
                /*
                 * "origin" is readonly but is used to receive datasets as
                 * clones so we don't raise an error here
                 */
                if (prop == ZFS_PROP_ORIGIN)
                        continue;

                /* encryption params have their own verification later */
                if (prop == ZFS_PROP_ENCRYPTION ||
                    zfs_prop_encryption_key_param(prop))
                        continue;

                /*
                 * cannot override readonly, set-once and other specific
                 * settable properties
                 */
                if (zfs_prop_readonly(prop) || prop == ZFS_PROP_VERSION ||
                    prop == ZFS_PROP_VOLSIZE) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "%s: invalid property '%s'"), errbuf, name);
                        return (B_FALSE);
                }
        }

        return (B_TRUE);
}

static int
zfs_receive_impl(libzfs_handle_t *hdl, const char *tosnap,
    const char *originsnap, recvflags_t *flags, int infd, const char *sendfs,
    nvlist_t *stream_nv, avl_tree_t *stream_avl, char **top_zfs,
    const char *finalsnap, nvlist_t *cmdprops)
{
        int err;
        dmu_replay_record_t drr, drr_noswap;
        struct drr_begin *drrb = &drr.drr_u.drr_begin;
        char errbuf[1024];
        zio_cksum_t zcksum = { { 0 } };
        uint64_t featureflags;
        int hdrtype;

        (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
            "cannot receive"));

        /* check cmdline props, raise an error if they cannot be received */
        if (!zfs_receive_checkprops(hdl, cmdprops, errbuf))
                return (zfs_error(hdl, EZFS_BADPROP, errbuf));

        if (flags->isprefix &&
            !zfs_dataset_exists(hdl, tosnap, ZFS_TYPE_DATASET)) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "specified fs "
                    "(%s) does not exist"), tosnap);
                return (zfs_error(hdl, EZFS_NOENT, errbuf));
        }
        if (originsnap &&
            !zfs_dataset_exists(hdl, originsnap, ZFS_TYPE_DATASET)) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "specified origin fs "
                    "(%s) does not exist"), originsnap);
                return (zfs_error(hdl, EZFS_NOENT, errbuf));
        }

        /* read in the BEGIN record */
        if (0 != (err = recv_read(hdl, infd, &drr, sizeof (drr), B_FALSE,
            &zcksum)))
                return (err);

        if (drr.drr_type == DRR_END || drr.drr_type == BSWAP_32(DRR_END)) {
                /* It's the double end record at the end of a package */
                return (ENODATA);
        }

        /* the kernel needs the non-byteswapped begin record */
        drr_noswap = drr;

        flags->byteswap = B_FALSE;
        if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC)) {
                /*
                 * We computed the checksum in the wrong byteorder in
                 * recv_read() above; do it again correctly.
                 */
                memset(&zcksum, 0, sizeof (zio_cksum_t));
                fletcher_4_incremental_byteswap(&drr, sizeof (drr), &zcksum);
                flags->byteswap = B_TRUE;

                drr.drr_type = BSWAP_32(drr.drr_type);
                drr.drr_payloadlen = BSWAP_32(drr.drr_payloadlen);
                drrb->drr_magic = BSWAP_64(drrb->drr_magic);
                drrb->drr_versioninfo = BSWAP_64(drrb->drr_versioninfo);
                drrb->drr_creation_time = BSWAP_64(drrb->drr_creation_time);
                drrb->drr_type = BSWAP_32(drrb->drr_type);
                drrb->drr_flags = BSWAP_32(drrb->drr_flags);
                drrb->drr_toguid = BSWAP_64(drrb->drr_toguid);
                drrb->drr_fromguid = BSWAP_64(drrb->drr_fromguid);
        }

        if (drrb->drr_magic != DMU_BACKUP_MAGIC || drr.drr_type != DRR_BEGIN) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                    "stream (bad magic number)"));
                return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
        }

        featureflags = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo);
        hdrtype = DMU_GET_STREAM_HDRTYPE(drrb->drr_versioninfo);

        if (!DMU_STREAM_SUPPORTED(featureflags) ||
            (hdrtype != DMU_SUBSTREAM && hdrtype != DMU_COMPOUNDSTREAM)) {
                /*
                 * Let's be explicit about this one, since rather than
                 * being a new feature we can't know, it's an old
                 * feature we dropped.
                 */
                if (featureflags & DMU_BACKUP_FEATURE_DEDUP) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "stream has deprecated feature: dedup, try "
                            "'zstream redup [send in a file] | zfs recv "
                            "[...]'"));
                } else {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "stream has unsupported feature, feature flags = "
                            "%llx (unknown flags = %llx)"),
                            (u_longlong_t)featureflags,
                            (u_longlong_t)((featureflags) &
                            ~DMU_BACKUP_FEATURE_MASK));
                }
                return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
        }

        /* Holds feature is set once in the compound stream header. */
        if (featureflags & DMU_BACKUP_FEATURE_HOLDS)
                flags->holds = B_TRUE;

        if (strchr(drrb->drr_toname, '@') == NULL) {
                zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                    "stream (bad snapshot name)"));
                return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
        }

        if (DMU_GET_STREAM_HDRTYPE(drrb->drr_versioninfo) == DMU_SUBSTREAM) {
                char nonpackage_sendfs[ZFS_MAX_DATASET_NAME_LEN];
                if (sendfs == NULL) {
                        /*
                         * We were not called from zfs_receive_package(). Get
                         * the fs specified by 'zfs send'.
                         */
                        char *cp;
                        (void) strlcpy(nonpackage_sendfs,
                            drr.drr_u.drr_begin.drr_toname,
                            sizeof (nonpackage_sendfs));
                        if ((cp = strchr(nonpackage_sendfs, '@')) != NULL)
                                *cp = '\0';
                        sendfs = nonpackage_sendfs;
                        VERIFY(finalsnap == NULL);
                }
                return (zfs_receive_one(hdl, infd, tosnap, originsnap, flags,
                    &drr, &drr_noswap, sendfs, stream_nv, stream_avl, top_zfs,
                    finalsnap, cmdprops));
        } else {
                assert(DMU_GET_STREAM_HDRTYPE(drrb->drr_versioninfo) ==
                    DMU_COMPOUNDSTREAM);
                return (zfs_receive_package(hdl, infd, tosnap, flags, &drr,
                    &zcksum, top_zfs, cmdprops));
        }
}

/*
 * Restores a backup of tosnap from the file descriptor specified by infd.
 * Return 0 on total success, -2 if some things couldn't be
 * destroyed/renamed/promoted, -1 if some things couldn't be received.
 * (-1 will override -2, if -1 and the resumable flag was specified the
 * transfer can be resumed if the sending side supports it).
 */
int
zfs_receive(libzfs_handle_t *hdl, const char *tosnap, nvlist_t *props,
    recvflags_t *flags, int infd, avl_tree_t *stream_avl)
{
        char *top_zfs = NULL;
        int err;
        struct stat sb;
        char *originsnap = NULL;

        /*
         * The only way fstat can fail is if we do not have a valid file
         * descriptor.
         */
        if (fstat(infd, &sb) == -1) {
                perror("fstat");
                return (-2);
        }

        if (props) {
                err = nvlist_lookup_string(props, "origin", &originsnap);
                if (err && err != ENOENT)
                        return (err);
        }

        err = zfs_receive_impl(hdl, tosnap, originsnap, flags, infd, NULL, NULL,
            stream_avl, &top_zfs, NULL, props);

        if (err == 0 && !flags->nomount && flags->domount && top_zfs) {
                zfs_handle_t *zhp = NULL;
                prop_changelist_t *clp = NULL;

                zhp = zfs_open(hdl, top_zfs,
                    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME);
                if (zhp == NULL) {
                        err = -1;
                        goto out;
                } else {
                        if (zhp->zfs_type == ZFS_TYPE_VOLUME) {
                                zfs_close(zhp);
                                goto out;
                        }

                        clp = changelist_gather(zhp, ZFS_PROP_MOUNTPOINT,
                            CL_GATHER_MOUNT_ALWAYS,
                            flags->forceunmount ? MS_FORCE : 0);
                        zfs_close(zhp);
                        if (clp == NULL) {
                                err = -1;
                                goto out;
                        }

                        /* mount and share received datasets */
                        err = changelist_postfix(clp);
                        changelist_free(clp);
                        if (err != 0)
                                err = -1;
                }
        }

out:
        if (top_zfs)
                free(top_zfs);

        return (err);
}