Linux 5.0 compat: ASM_BUG macro

[mirror_zfs.git] / module / nvpair / nvpair.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) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2015, 2017 by Delphix. All rights reserved.
 * Copyright 2018 RackTop Systems.
 */

#include <sys/debug.h>
#include <sys/isa_defs.h>
#include <sys/nvpair.h>
#include <sys/nvpair_impl.h>
#include <sys/types.h>
#include <sys/strings.h>
#include <rpc/xdr.h>

#if defined(_KERNEL)
#include <sys/sunddi.h>
#include <sys/sysmacros.h>
#else
#include <stdarg.h>
#include <stdlib.h>
#include <stddef.h>
#endif

#define skip_whitespace(p)      while ((*(p) == ' ') || (*(p) == '\t')) p++

/*
 * nvpair.c - Provides kernel & userland interfaces for manipulating
 *      name-value pairs.
 *
 * Overview Diagram
 *
 *  +--------------+
 *  |  nvlist_t    |
 *  |--------------|
 *  | nvl_version  |
 *  | nvl_nvflag   |
 *  | nvl_priv    -+-+
 *  | nvl_flag     | |
 *  | nvl_pad      | |
 *  +--------------+ |
 *                   V
 *      +--------------+      last i_nvp in list
 *      | nvpriv_t     |  +--------------------->
 *      |--------------|  |
 *   +--+- nvp_list    |  |   +------------+
 *   |  |  nvp_last   -+--+   + nv_alloc_t |
 *   |  |  nvp_curr    |      |------------|
 *   |  |  nvp_nva    -+----> | nva_ops    |
 *   |  |  nvp_stat    |      | nva_arg    |
 *   |  +--------------+      +------------+
 *   |
 *   +-------+
 *           V
 *   +---------------------+      +-------------------+
 *   |  i_nvp_t            |  +-->|  i_nvp_t          |  +-->
 *   |---------------------|  |   |-------------------|  |
 *   | nvi_next           -+--+   | nvi_next         -+--+
 *   | nvi_prev (NULL)     | <----+ nvi_prev          |
 *   | . . . . . . . . . . |      | . . . . . . . . . |
 *   | nvp (nvpair_t)      |      | nvp (nvpair_t)    |
 *   |  - nvp_size         |      |  - nvp_size       |
 *   |  - nvp_name_sz      |      |  - nvp_name_sz    |
 *   |  - nvp_value_elem   |      |  - nvp_value_elem |
 *   |  - nvp_type         |      |  - nvp_type       |
 *   |  - data ...         |      |  - data ...       |
 *   +---------------------+      +-------------------+
 *
 *
 *
 *   +---------------------+              +---------------------+
 *   |  i_nvp_t            |  +-->    +-->|  i_nvp_t (last)     |
 *   |---------------------|  |       |   |---------------------|
 *   |  nvi_next          -+--+ ... --+   | nvi_next (NULL)     |
 * <-+- nvi_prev           |<-- ...  <----+ nvi_prev            |
 *   | . . . . . . . . .   |              | . . . . . . . . .   |
 *   | nvp (nvpair_t)      |              | nvp (nvpair_t)      |
 *   |  - nvp_size         |              |  - nvp_size         |
 *   |  - nvp_name_sz      |              |  - nvp_name_sz      |
 *   |  - nvp_value_elem   |              |  - nvp_value_elem   |
 *   |  - DATA_TYPE_NVLIST |              |  - nvp_type         |
 *   |  - data (embedded)  |              |  - data ...         |
 *   |    nvlist name      |              +---------------------+
 *   |  +--------------+   |
 *   |  |  nvlist_t    |   |
 *   |  |--------------|   |
 *   |  | nvl_version  |   |
 *   |  | nvl_nvflag   |   |
 *   |  | nvl_priv   --+---+---->
 *   |  | nvl_flag     |   |
 *   |  | nvl_pad      |   |
 *   |  +--------------+   |
 *   +---------------------+
 *
 *
 * N.B. nvpair_t may be aligned on 4 byte boundary, so +4 will
 * allow value to be aligned on 8 byte boundary
 *
 * name_len is the length of the name string including the null terminator
 * so it must be >= 1
 */
#define NVP_SIZE_CALC(name_len, data_len) \
        (NV_ALIGN((sizeof (nvpair_t)) + name_len) + NV_ALIGN(data_len))

static int i_get_value_size(data_type_t type, const void *data, uint_t nelem);
static int nvlist_add_common(nvlist_t *nvl, const char *name, data_type_t type,
    uint_t nelem, const void *data);

#define NV_STAT_EMBEDDED        0x1
#define EMBEDDED_NVL(nvp)       ((nvlist_t *)(void *)NVP_VALUE(nvp))
#define EMBEDDED_NVL_ARRAY(nvp) ((nvlist_t **)(void *)NVP_VALUE(nvp))

#define NVP_VALOFF(nvp) (NV_ALIGN(sizeof (nvpair_t) + (nvp)->nvp_name_sz))
#define NVPAIR2I_NVP(nvp) \
        ((i_nvp_t *)((size_t)(nvp) - offsetof(i_nvp_t, nvi_nvp)))

#ifdef _KERNEL
int nvpair_max_recursion = 20;
#else
int nvpair_max_recursion = 100;
#endif

uint64_t nvlist_hashtable_init_size = (1 << 4);

int
nv_alloc_init(nv_alloc_t *nva, const nv_alloc_ops_t *nvo, /* args */ ...)
{
        va_list valist;
        int err = 0;

        nva->nva_ops = nvo;
        nva->nva_arg = NULL;

        va_start(valist, nvo);
        if (nva->nva_ops->nv_ao_init != NULL)
                err = nva->nva_ops->nv_ao_init(nva, valist);
        va_end(valist);

        return (err);
}

void
nv_alloc_reset(nv_alloc_t *nva)
{
        if (nva->nva_ops->nv_ao_reset != NULL)
                nva->nva_ops->nv_ao_reset(nva);
}

void
nv_alloc_fini(nv_alloc_t *nva)
{
        if (nva->nva_ops->nv_ao_fini != NULL)
                nva->nva_ops->nv_ao_fini(nva);
}

nv_alloc_t *
nvlist_lookup_nv_alloc(nvlist_t *nvl)
{
        nvpriv_t *priv;

        if (nvl == NULL ||
            (priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
                return (NULL);

        return (priv->nvp_nva);
}

static void *
nv_mem_zalloc(nvpriv_t *nvp, size_t size)
{
        nv_alloc_t *nva = nvp->nvp_nva;
        void *buf;

        if ((buf = nva->nva_ops->nv_ao_alloc(nva, size)) != NULL)
                bzero(buf, size);

        return (buf);
}

static void
nv_mem_free(nvpriv_t *nvp, void *buf, size_t size)
{
        nv_alloc_t *nva = nvp->nvp_nva;

        nva->nva_ops->nv_ao_free(nva, buf, size);
}

static void
nv_priv_init(nvpriv_t *priv, nv_alloc_t *nva, uint32_t stat)
{
        bzero(priv, sizeof (nvpriv_t));

        priv->nvp_nva = nva;
        priv->nvp_stat = stat;
}

static nvpriv_t *
nv_priv_alloc(nv_alloc_t *nva)
{
        nvpriv_t *priv;

        /*
         * nv_mem_alloc() cannot called here because it needs the priv
         * argument.
         */
        if ((priv = nva->nva_ops->nv_ao_alloc(nva, sizeof (nvpriv_t))) == NULL)
                return (NULL);

        nv_priv_init(priv, nva, 0);

        return (priv);
}

/*
 * Embedded lists need their own nvpriv_t's.  We create a new
 * nvpriv_t using the parameters and allocator from the parent
 * list's nvpriv_t.
 */
static nvpriv_t *
nv_priv_alloc_embedded(nvpriv_t *priv)
{
        nvpriv_t *emb_priv;

        if ((emb_priv = nv_mem_zalloc(priv, sizeof (nvpriv_t))) == NULL)
                return (NULL);

        nv_priv_init(emb_priv, priv->nvp_nva, NV_STAT_EMBEDDED);

        return (emb_priv);
}

static int
nvt_tab_alloc(nvpriv_t *priv, uint64_t buckets)
{
        ASSERT3P(priv->nvp_hashtable, ==, NULL);
        ASSERT0(priv->nvp_nbuckets);
        ASSERT0(priv->nvp_nentries);

        i_nvp_t **tab = nv_mem_zalloc(priv, buckets * sizeof (i_nvp_t *));
        if (tab == NULL)
                return (ENOMEM);

        priv->nvp_hashtable = tab;
        priv->nvp_nbuckets = buckets;
        return (0);
}

static void
nvt_tab_free(nvpriv_t *priv)
{
        i_nvp_t **tab = priv->nvp_hashtable;
        if (tab == NULL) {
                ASSERT0(priv->nvp_nbuckets);
                ASSERT0(priv->nvp_nentries);
                return;
        }

        nv_mem_free(priv, tab, priv->nvp_nbuckets * sizeof (i_nvp_t *));

        priv->nvp_hashtable = NULL;
        priv->nvp_nbuckets = 0;
        priv->nvp_nentries = 0;
}

static uint32_t
nvt_hash(const char *p)
{
        uint32_t g, hval = 0;

        while (*p) {
                hval = (hval << 4) + *p++;
                if ((g = (hval & 0xf0000000)) != 0)
                        hval ^= g >> 24;
                hval &= ~g;
        }
        return (hval);
}

static boolean_t
nvt_nvpair_match(nvpair_t *nvp1, nvpair_t *nvp2, uint32_t nvflag)
{
        boolean_t match = B_FALSE;
        if (nvflag & NV_UNIQUE_NAME_TYPE) {
                if (strcmp(NVP_NAME(nvp1), NVP_NAME(nvp2)) == 0 &&
                    NVP_TYPE(nvp1) == NVP_TYPE(nvp2))
                        match = B_TRUE;
        } else {
                ASSERT(nvflag == 0 || nvflag & NV_UNIQUE_NAME);
                if (strcmp(NVP_NAME(nvp1), NVP_NAME(nvp2)) == 0)
                        match = B_TRUE;
        }
        return (match);
}

static nvpair_t *
nvt_lookup_name_type(nvlist_t *nvl, const char *name, data_type_t type)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        ASSERT(priv != NULL);

        i_nvp_t **tab = priv->nvp_hashtable;

        if (tab == NULL) {
                ASSERT3P(priv->nvp_list, ==, NULL);
                ASSERT0(priv->nvp_nbuckets);
                ASSERT0(priv->nvp_nentries);
                return (NULL);
        } else {
                ASSERT(priv->nvp_nbuckets != 0);
        }

        uint64_t hash = nvt_hash(name);
        uint64_t index = hash & (priv->nvp_nbuckets - 1);

        ASSERT3U(index, <, priv->nvp_nbuckets);
        i_nvp_t *entry = tab[index];

        for (i_nvp_t *e = entry; e != NULL; e = e->nvi_hashtable_next) {
                if (strcmp(NVP_NAME(&e->nvi_nvp), name) == 0 &&
                    (type == DATA_TYPE_DONTCARE ||
                    NVP_TYPE(&e->nvi_nvp) == type))
                        return (&e->nvi_nvp);
        }
        return (NULL);
}

static nvpair_t *
nvt_lookup_name(nvlist_t *nvl, const char *name)
{
        return (nvt_lookup_name_type(nvl, name, DATA_TYPE_DONTCARE));
}

static int
nvt_resize(nvpriv_t *priv, uint32_t new_size)
{
        i_nvp_t **tab = priv->nvp_hashtable;

        /*
         * Migrate all the entries from the current table
         * to a newly-allocated table with the new size by
         * re-adjusting the pointers of their entries.
         */
        uint32_t size = priv->nvp_nbuckets;
        uint32_t new_mask = new_size - 1;
        ASSERT(ISP2(new_size));

        i_nvp_t **new_tab = nv_mem_zalloc(priv, new_size * sizeof (i_nvp_t *));
        if (new_tab == NULL)
                return (ENOMEM);

        uint32_t nentries = 0;
        for (uint32_t i = 0; i < size; i++) {
                i_nvp_t *next, *e = tab[i];

                while (e != NULL) {
                        next = e->nvi_hashtable_next;

                        uint32_t hash = nvt_hash(NVP_NAME(&e->nvi_nvp));
                        uint32_t index = hash & new_mask;

                        e->nvi_hashtable_next = new_tab[index];
                        new_tab[index] = e;
                        nentries++;

                        e = next;
                }
                tab[i] = NULL;
        }
        ASSERT3U(nentries, ==, priv->nvp_nentries);

        nvt_tab_free(priv);

        priv->nvp_hashtable = new_tab;
        priv->nvp_nbuckets = new_size;
        priv->nvp_nentries = nentries;

        return (0);
}

static boolean_t
nvt_needs_togrow(nvpriv_t *priv)
{
        /*
         * Grow only when we have more elements than buckets
         * and the # of buckets doesn't overflow.
         */
        return (priv->nvp_nentries > priv->nvp_nbuckets &&
            (UINT32_MAX >> 1) >= priv->nvp_nbuckets);
}

/*
 * Allocate a new table that's twice the size of the old one,
 * and migrate all the entries from the old one to the new
 * one by re-adjusting their pointers.
 */
static int
nvt_grow(nvpriv_t *priv)
{
        uint32_t current_size = priv->nvp_nbuckets;
        /* ensure we won't overflow */
        ASSERT3U(UINT32_MAX >> 1, >=, current_size);
        return (nvt_resize(priv, current_size << 1));
}

static boolean_t
nvt_needs_toshrink(nvpriv_t *priv)
{
        /*
         * Shrink only when the # of elements is less than or
         * equal to 1/4 the # of buckets. Never shrink less than
         * nvlist_hashtable_init_size.
         */
        ASSERT3U(priv->nvp_nbuckets, >=, nvlist_hashtable_init_size);
        if (priv->nvp_nbuckets == nvlist_hashtable_init_size)
                return (B_FALSE);
        return (priv->nvp_nentries <= (priv->nvp_nbuckets >> 2));
}

/*
 * Allocate a new table that's half the size of the old one,
 * and migrate all the entries from the old one to the new
 * one by re-adjusting their pointers.
 */
static int
nvt_shrink(nvpriv_t *priv)
{
        uint32_t current_size = priv->nvp_nbuckets;
        /* ensure we won't overflow */
        ASSERT3U(current_size, >=, nvlist_hashtable_init_size);
        return (nvt_resize(priv, current_size >> 1));
}

static int
nvt_remove_nvpair(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;

        if (nvt_needs_toshrink(priv)) {
                int err = nvt_shrink(priv);
                if (err != 0)
                        return (err);
        }
        i_nvp_t **tab = priv->nvp_hashtable;

        char *name = NVP_NAME(nvp);
        uint64_t hash = nvt_hash(name);
        uint64_t index = hash & (priv->nvp_nbuckets - 1);

        ASSERT3U(index, <, priv->nvp_nbuckets);
        i_nvp_t *bucket = tab[index];

        for (i_nvp_t *prev = NULL, *e = bucket;
            e != NULL; prev = e, e = e->nvi_hashtable_next) {
                if (nvt_nvpair_match(&e->nvi_nvp, nvp, nvl->nvl_nvflag)) {
                        if (prev != NULL) {
                                prev->nvi_hashtable_next =
                                    e->nvi_hashtable_next;
                        } else {
                                ASSERT3P(e, ==, bucket);
                                tab[index] = e->nvi_hashtable_next;
                        }
                        e->nvi_hashtable_next = NULL;
                        priv->nvp_nentries--;
                        break;
                }
        }

        return (0);
}

static int
nvt_add_nvpair(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;

        /* initialize nvpair table now if it doesn't exist. */
        if (priv->nvp_hashtable == NULL) {
                int err = nvt_tab_alloc(priv, nvlist_hashtable_init_size);
                if (err != 0)
                        return (err);
        }

        /*
         * if we don't allow duplicate entries, make sure to
         * unlink any existing entries from the table.
         */
        if (nvl->nvl_nvflag != 0) {
                int err = nvt_remove_nvpair(nvl, nvp);
                if (err != 0)
                        return (err);
        }

        if (nvt_needs_togrow(priv)) {
                int err = nvt_grow(priv);
                if (err != 0)
                        return (err);
        }
        i_nvp_t **tab = priv->nvp_hashtable;

        char *name = NVP_NAME(nvp);
        uint64_t hash = nvt_hash(name);
        uint64_t index = hash & (priv->nvp_nbuckets - 1);

        ASSERT3U(index, <, priv->nvp_nbuckets);
        i_nvp_t *bucket = tab[index];

        /* insert link at the beginning of the bucket */
        i_nvp_t *new_entry = NVPAIR2I_NVP(nvp);
        ASSERT3P(new_entry->nvi_hashtable_next, ==, NULL);
        new_entry->nvi_hashtable_next = bucket;
        tab[index] = new_entry;

        priv->nvp_nentries++;
        return (0);
}

static void
nvlist_init(nvlist_t *nvl, uint32_t nvflag, nvpriv_t *priv)
{
        nvl->nvl_version = NV_VERSION;
        nvl->nvl_nvflag = nvflag & (NV_UNIQUE_NAME|NV_UNIQUE_NAME_TYPE);
        nvl->nvl_priv = (uint64_t)(uintptr_t)priv;
        nvl->nvl_flag = 0;
        nvl->nvl_pad = 0;
}

uint_t
nvlist_nvflag(nvlist_t *nvl)
{
        return (nvl->nvl_nvflag);
}

static nv_alloc_t *
nvlist_nv_alloc(int kmflag)
{
#if defined(_KERNEL)
        switch (kmflag) {
        case KM_SLEEP:
                return (nv_alloc_sleep);
        case KM_PUSHPAGE:
                return (nv_alloc_pushpage);
        default:
                return (nv_alloc_nosleep);
        }
#else
        return (nv_alloc_nosleep);
#endif /* _KERNEL */
}

/*
 * nvlist_alloc - Allocate nvlist.
 */
int
nvlist_alloc(nvlist_t **nvlp, uint_t nvflag, int kmflag)
{
        return (nvlist_xalloc(nvlp, nvflag, nvlist_nv_alloc(kmflag)));
}

int
nvlist_xalloc(nvlist_t **nvlp, uint_t nvflag, nv_alloc_t *nva)
{
        nvpriv_t *priv;

        if (nvlp == NULL || nva == NULL)
                return (EINVAL);

        if ((priv = nv_priv_alloc(nva)) == NULL)
                return (ENOMEM);

        if ((*nvlp = nv_mem_zalloc(priv,
            NV_ALIGN(sizeof (nvlist_t)))) == NULL) {
                nv_mem_free(priv, priv, sizeof (nvpriv_t));
                return (ENOMEM);
        }

        nvlist_init(*nvlp, nvflag, priv);

        return (0);
}

/*
 * nvp_buf_alloc - Allocate i_nvp_t for storing a new nv pair.
 */
static nvpair_t *
nvp_buf_alloc(nvlist_t *nvl, size_t len)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        i_nvp_t *buf;
        nvpair_t *nvp;
        size_t nvsize;

        /*
         * Allocate the buffer
         */
        nvsize = len + offsetof(i_nvp_t, nvi_nvp);

        if ((buf = nv_mem_zalloc(priv, nvsize)) == NULL)
                return (NULL);

        nvp = &buf->nvi_nvp;
        nvp->nvp_size = len;

        return (nvp);
}

/*
 * nvp_buf_free - de-Allocate an i_nvp_t.
 */
static void
nvp_buf_free(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        size_t nvsize = nvp->nvp_size + offsetof(i_nvp_t, nvi_nvp);

        nv_mem_free(priv, NVPAIR2I_NVP(nvp), nvsize);
}

/*
 * nvp_buf_link - link a new nv pair into the nvlist.
 */
static void
nvp_buf_link(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        i_nvp_t *curr = NVPAIR2I_NVP(nvp);

        /* Put element at end of nvlist */
        if (priv->nvp_list == NULL) {
                priv->nvp_list = priv->nvp_last = curr;
        } else {
                curr->nvi_prev = priv->nvp_last;
                priv->nvp_last->nvi_next = curr;
                priv->nvp_last = curr;
        }
}

/*
 * nvp_buf_unlink - unlink an removed nvpair out of the nvlist.
 */
static void
nvp_buf_unlink(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        i_nvp_t *curr = NVPAIR2I_NVP(nvp);

        /*
         * protect nvlist_next_nvpair() against walking on freed memory.
         */
        if (priv->nvp_curr == curr)
                priv->nvp_curr = curr->nvi_next;

        if (curr == priv->nvp_list)
                priv->nvp_list = curr->nvi_next;
        else
                curr->nvi_prev->nvi_next = curr->nvi_next;

        if (curr == priv->nvp_last)
                priv->nvp_last = curr->nvi_prev;
        else
                curr->nvi_next->nvi_prev = curr->nvi_prev;
}

/*
 * take a nvpair type and number of elements and make sure the are valid
 */
static int
i_validate_type_nelem(data_type_t type, uint_t nelem)
{
        switch (type) {
        case DATA_TYPE_BOOLEAN:
                if (nelem != 0)
                        return (EINVAL);
                break;
        case DATA_TYPE_BOOLEAN_VALUE:
        case DATA_TYPE_BYTE:
        case DATA_TYPE_INT8:
        case DATA_TYPE_UINT8:
        case DATA_TYPE_INT16:
        case DATA_TYPE_UINT16:
        case DATA_TYPE_INT32:
        case DATA_TYPE_UINT32:
        case DATA_TYPE_INT64:
        case DATA_TYPE_UINT64:
        case DATA_TYPE_STRING:
        case DATA_TYPE_HRTIME:
        case DATA_TYPE_NVLIST:
#if !defined(_KERNEL)
        case DATA_TYPE_DOUBLE:
#endif
                if (nelem != 1)
                        return (EINVAL);
                break;
        case DATA_TYPE_BOOLEAN_ARRAY:
        case DATA_TYPE_BYTE_ARRAY:
        case DATA_TYPE_INT8_ARRAY:
        case DATA_TYPE_UINT8_ARRAY:
        case DATA_TYPE_INT16_ARRAY:
        case DATA_TYPE_UINT16_ARRAY:
        case DATA_TYPE_INT32_ARRAY:
        case DATA_TYPE_UINT32_ARRAY:
        case DATA_TYPE_INT64_ARRAY:
        case DATA_TYPE_UINT64_ARRAY:
        case DATA_TYPE_STRING_ARRAY:
        case DATA_TYPE_NVLIST_ARRAY:
                /* we allow arrays with 0 elements */
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

/*
 * Verify nvp_name_sz and check the name string length.
 */
static int
i_validate_nvpair_name(nvpair_t *nvp)
{
        if ((nvp->nvp_name_sz <= 0) ||
            (nvp->nvp_size < NVP_SIZE_CALC(nvp->nvp_name_sz, 0)))
                return (EFAULT);

        /* verify the name string, make sure its terminated */
        if (NVP_NAME(nvp)[nvp->nvp_name_sz - 1] != '\0')
                return (EFAULT);

        return (strlen(NVP_NAME(nvp)) == nvp->nvp_name_sz - 1 ? 0 : EFAULT);
}

static int
i_validate_nvpair_value(data_type_t type, uint_t nelem, const void *data)
{
        switch (type) {
        case DATA_TYPE_BOOLEAN_VALUE:
                if (*(boolean_t *)data != B_TRUE &&
                    *(boolean_t *)data != B_FALSE)
                        return (EINVAL);
                break;
        case DATA_TYPE_BOOLEAN_ARRAY: {
                int i;

                for (i = 0; i < nelem; i++)
                        if (((boolean_t *)data)[i] != B_TRUE &&
                            ((boolean_t *)data)[i] != B_FALSE)
                                return (EINVAL);
                break;
        }
        default:
                break;
        }

        return (0);
}

/*
 * This function takes a pointer to what should be a nvpair and it's size
 * and then verifies that all the nvpair fields make sense and can be
 * trusted.  This function is used when decoding packed nvpairs.
 */
static int
i_validate_nvpair(nvpair_t *nvp)
{
        data_type_t type = NVP_TYPE(nvp);
        int size1, size2;

        /* verify nvp_name_sz, check the name string length */
        if (i_validate_nvpair_name(nvp) != 0)
                return (EFAULT);

        if (i_validate_nvpair_value(type, NVP_NELEM(nvp), NVP_VALUE(nvp)) != 0)
                return (EFAULT);

        /*
         * verify nvp_type, nvp_value_elem, and also possibly
         * verify string values and get the value size.
         */
        size2 = i_get_value_size(type, NVP_VALUE(nvp), NVP_NELEM(nvp));
        size1 = nvp->nvp_size - NVP_VALOFF(nvp);
        if (size2 < 0 || size1 != NV_ALIGN(size2))
                return (EFAULT);

        return (0);
}

static int
nvlist_copy_pairs(nvlist_t *snvl, nvlist_t *dnvl)
{
        nvpriv_t *priv;
        i_nvp_t *curr;

        if ((priv = (nvpriv_t *)(uintptr_t)snvl->nvl_priv) == NULL)
                return (EINVAL);

        for (curr = priv->nvp_list; curr != NULL; curr = curr->nvi_next) {
                nvpair_t *nvp = &curr->nvi_nvp;
                int err;

                if ((err = nvlist_add_common(dnvl, NVP_NAME(nvp), NVP_TYPE(nvp),
                    NVP_NELEM(nvp), NVP_VALUE(nvp))) != 0)
                        return (err);
        }

        return (0);
}

/*
 * Frees all memory allocated for an nvpair (like embedded lists) with
 * the exception of the nvpair buffer itself.
 */
static void
nvpair_free(nvpair_t *nvp)
{
        switch (NVP_TYPE(nvp)) {
        case DATA_TYPE_NVLIST:
                nvlist_free(EMBEDDED_NVL(nvp));
                break;
        case DATA_TYPE_NVLIST_ARRAY: {
                nvlist_t **nvlp = EMBEDDED_NVL_ARRAY(nvp);
                int i;

                for (i = 0; i < NVP_NELEM(nvp); i++)
                        if (nvlp[i] != NULL)
                                nvlist_free(nvlp[i]);
                break;
        }
        default:
                break;
        }
}

/*
 * nvlist_free - free an unpacked nvlist
 */
void
nvlist_free(nvlist_t *nvl)
{
        nvpriv_t *priv;
        i_nvp_t *curr;

        if (nvl == NULL ||
            (priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
                return;

        /*
         * Unpacked nvlist are linked through i_nvp_t
         */
        curr = priv->nvp_list;
        while (curr != NULL) {
                nvpair_t *nvp = &curr->nvi_nvp;
                curr = curr->nvi_next;

                nvpair_free(nvp);
                nvp_buf_free(nvl, nvp);
        }

        if (!(priv->nvp_stat & NV_STAT_EMBEDDED))
                nv_mem_free(priv, nvl, NV_ALIGN(sizeof (nvlist_t)));
        else
                nvl->nvl_priv = 0;

        nvt_tab_free(priv);
        nv_mem_free(priv, priv, sizeof (nvpriv_t));
}

static int
nvlist_contains_nvp(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        i_nvp_t *curr;

        if (nvp == NULL)
                return (0);

        for (curr = priv->nvp_list; curr != NULL; curr = curr->nvi_next)
                if (&curr->nvi_nvp == nvp)
                        return (1);

        return (0);
}

/*
 * Make a copy of nvlist
 */
int
nvlist_dup(nvlist_t *nvl, nvlist_t **nvlp, int kmflag)
{
        return (nvlist_xdup(nvl, nvlp, nvlist_nv_alloc(kmflag)));
}

int
nvlist_xdup(nvlist_t *nvl, nvlist_t **nvlp, nv_alloc_t *nva)
{
        int err;
        nvlist_t *ret;

        if (nvl == NULL || nvlp == NULL)
                return (EINVAL);

        if ((err = nvlist_xalloc(&ret, nvl->nvl_nvflag, nva)) != 0)
                return (err);

        if ((err = nvlist_copy_pairs(nvl, ret)) != 0)
                nvlist_free(ret);
        else
                *nvlp = ret;

        return (err);
}

/*
 * Remove all with matching name
 */
int
nvlist_remove_all(nvlist_t *nvl, const char *name)
{
        int error = ENOENT;

        if (nvl == NULL || name == NULL || nvl->nvl_priv == 0)
                return (EINVAL);

        nvpair_t *nvp;
        while ((nvp = nvt_lookup_name(nvl, name)) != NULL) {
                VERIFY0(nvlist_remove_nvpair(nvl, nvp));
                error = 0;
        }

        return (error);
}

/*
 * Remove first one with matching name and type
 */
int
nvlist_remove(nvlist_t *nvl, const char *name, data_type_t type)
{
        if (nvl == NULL || name == NULL || nvl->nvl_priv == 0)
                return (EINVAL);

        nvpair_t *nvp = nvt_lookup_name_type(nvl, name, type);
        if (nvp == NULL)
                return (ENOENT);

        return (nvlist_remove_nvpair(nvl, nvp));
}

int
nvlist_remove_nvpair(nvlist_t *nvl, nvpair_t *nvp)
{
        if (nvl == NULL || nvp == NULL)
                return (EINVAL);

        int err = nvt_remove_nvpair(nvl, nvp);
        if (err != 0)
                return (err);

        nvp_buf_unlink(nvl, nvp);
        nvpair_free(nvp);
        nvp_buf_free(nvl, nvp);
        return (0);
}

/*
 * This function calculates the size of an nvpair value.
 *
 * The data argument controls the behavior in case of the data types
 *      DATA_TYPE_STRING        and
 *      DATA_TYPE_STRING_ARRAY
 * Is data == NULL then the size of the string(s) is excluded.
 */
static int
i_get_value_size(data_type_t type, const void *data, uint_t nelem)
{
        uint64_t value_sz;

        if (i_validate_type_nelem(type, nelem) != 0)
                return (-1);

        /* Calculate required size for holding value */
        switch (type) {
        case DATA_TYPE_BOOLEAN:
                value_sz = 0;
                break;
        case DATA_TYPE_BOOLEAN_VALUE:
                value_sz = sizeof (boolean_t);
                break;
        case DATA_TYPE_BYTE:
                value_sz = sizeof (uchar_t);
                break;
        case DATA_TYPE_INT8:
                value_sz = sizeof (int8_t);
                break;
        case DATA_TYPE_UINT8:
                value_sz = sizeof (uint8_t);
                break;
        case DATA_TYPE_INT16:
                value_sz = sizeof (int16_t);
                break;
        case DATA_TYPE_UINT16:
                value_sz = sizeof (uint16_t);
                break;
        case DATA_TYPE_INT32:
                value_sz = sizeof (int32_t);
                break;
        case DATA_TYPE_UINT32:
                value_sz = sizeof (uint32_t);
                break;
        case DATA_TYPE_INT64:
                value_sz = sizeof (int64_t);
                break;
        case DATA_TYPE_UINT64:
                value_sz = sizeof (uint64_t);
                break;
#if !defined(_KERNEL)
        case DATA_TYPE_DOUBLE:
                value_sz = sizeof (double);
                break;
#endif
        case DATA_TYPE_STRING:
                if (data == NULL)
                        value_sz = 0;
                else
                        value_sz = strlen(data) + 1;
                break;
        case DATA_TYPE_BOOLEAN_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (boolean_t);
                break;
        case DATA_TYPE_BYTE_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (uchar_t);
                break;
        case DATA_TYPE_INT8_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (int8_t);
                break;
        case DATA_TYPE_UINT8_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (uint8_t);
                break;
        case DATA_TYPE_INT16_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (int16_t);
                break;
        case DATA_TYPE_UINT16_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (uint16_t);
                break;
        case DATA_TYPE_INT32_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (int32_t);
                break;
        case DATA_TYPE_UINT32_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (uint32_t);
                break;
        case DATA_TYPE_INT64_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (int64_t);
                break;
        case DATA_TYPE_UINT64_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (uint64_t);
                break;
        case DATA_TYPE_STRING_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (uint64_t);

                if (data != NULL) {
                        char *const *strs = data;
                        uint_t i;

                        /* no alignment requirement for strings */
                        for (i = 0; i < nelem; i++) {
                                if (strs[i] == NULL)
                                        return (-1);
                                value_sz += strlen(strs[i]) + 1;
                        }
                }
                break;
        case DATA_TYPE_HRTIME:
                value_sz = sizeof (hrtime_t);
                break;
        case DATA_TYPE_NVLIST:
                value_sz = NV_ALIGN(sizeof (nvlist_t));
                break;
        case DATA_TYPE_NVLIST_ARRAY:
                value_sz = (uint64_t)nelem * sizeof (uint64_t) +
                    (uint64_t)nelem * NV_ALIGN(sizeof (nvlist_t));
                break;
        default:
                return (-1);
        }

        return (value_sz > INT32_MAX ? -1 : (int)value_sz);
}

static int
nvlist_copy_embedded(nvlist_t *nvl, nvlist_t *onvl, nvlist_t *emb_nvl)
{
        nvpriv_t *priv;
        int err;

        if ((priv = nv_priv_alloc_embedded((nvpriv_t *)(uintptr_t)
            nvl->nvl_priv)) == NULL)
                return (ENOMEM);

        nvlist_init(emb_nvl, onvl->nvl_nvflag, priv);

        if ((err = nvlist_copy_pairs(onvl, emb_nvl)) != 0) {
                nvlist_free(emb_nvl);
                emb_nvl->nvl_priv = 0;
        }

        return (err);
}

/*
 * nvlist_add_common - Add new <name,value> pair to nvlist
 */
static int
nvlist_add_common(nvlist_t *nvl, const char *name,
    data_type_t type, uint_t nelem, const void *data)
{
        nvpair_t *nvp;
        uint_t i;

        int nvp_sz, name_sz, value_sz;
        int err = 0;

        if (name == NULL || nvl == NULL || nvl->nvl_priv == 0)
                return (EINVAL);

        if (nelem != 0 && data == NULL)
                return (EINVAL);

        /*
         * Verify type and nelem and get the value size.
         * In case of data types DATA_TYPE_STRING and DATA_TYPE_STRING_ARRAY
         * is the size of the string(s) included.
         */
        if ((value_sz = i_get_value_size(type, data, nelem)) < 0)
                return (EINVAL);

        if (i_validate_nvpair_value(type, nelem, data) != 0)
                return (EINVAL);

        /*
         * If we're adding an nvlist or nvlist array, ensure that we are not
         * adding the input nvlist to itself, which would cause recursion,
         * and ensure that no NULL nvlist pointers are present.
         */
        switch (type) {
        case DATA_TYPE_NVLIST:
                if (data == nvl || data == NULL)
                        return (EINVAL);
                break;
        case DATA_TYPE_NVLIST_ARRAY: {
                nvlist_t **onvlp = (nvlist_t **)data;
                for (i = 0; i < nelem; i++) {
                        if (onvlp[i] == nvl || onvlp[i] == NULL)
                                return (EINVAL);
                }
                break;
        }
        default:
                break;
        }

        /* calculate sizes of the nvpair elements and the nvpair itself */
        name_sz = strlen(name) + 1;
        if (name_sz >= 1ULL << (sizeof (nvp->nvp_name_sz) * NBBY - 1))
                return (EINVAL);

        nvp_sz = NVP_SIZE_CALC(name_sz, value_sz);

        if ((nvp = nvp_buf_alloc(nvl, nvp_sz)) == NULL)
                return (ENOMEM);

        ASSERT(nvp->nvp_size == nvp_sz);
        nvp->nvp_name_sz = name_sz;
        nvp->nvp_value_elem = nelem;
        nvp->nvp_type = type;
        bcopy(name, NVP_NAME(nvp), name_sz);

        switch (type) {
        case DATA_TYPE_BOOLEAN:
                break;
        case DATA_TYPE_STRING_ARRAY: {
                char *const *strs = data;
                char *buf = NVP_VALUE(nvp);
                char **cstrs = (void *)buf;

                /* skip pre-allocated space for pointer array */
                buf += nelem * sizeof (uint64_t);
                for (i = 0; i < nelem; i++) {
                        int slen = strlen(strs[i]) + 1;
                        bcopy(strs[i], buf, slen);
                        cstrs[i] = buf;
                        buf += slen;
                }
                break;
        }
        case DATA_TYPE_NVLIST: {
                nvlist_t *nnvl = EMBEDDED_NVL(nvp);
                nvlist_t *onvl = (nvlist_t *)data;

                if ((err = nvlist_copy_embedded(nvl, onvl, nnvl)) != 0) {
                        nvp_buf_free(nvl, nvp);
                        return (err);
                }
                break;
        }
        case DATA_TYPE_NVLIST_ARRAY: {
                nvlist_t **onvlp = (nvlist_t **)data;
                nvlist_t **nvlp = EMBEDDED_NVL_ARRAY(nvp);
                nvlist_t *embedded = (nvlist_t *)
                    ((uintptr_t)nvlp + nelem * sizeof (uint64_t));

                for (i = 0; i < nelem; i++) {
                        if ((err = nvlist_copy_embedded(nvl,
                            onvlp[i], embedded)) != 0) {
                                /*
                                 * Free any successfully created lists
                                 */
                                nvpair_free(nvp);
                                nvp_buf_free(nvl, nvp);
                                return (err);
                        }

                        nvlp[i] = embedded++;
                }
                break;
        }
        default:
                bcopy(data, NVP_VALUE(nvp), value_sz);
        }

        /* if unique name, remove before add */
        if (nvl->nvl_nvflag & NV_UNIQUE_NAME)
                (void) nvlist_remove_all(nvl, name);
        else if (nvl->nvl_nvflag & NV_UNIQUE_NAME_TYPE)
                (void) nvlist_remove(nvl, name, type);

        err = nvt_add_nvpair(nvl, nvp);
        if (err != 0) {
                nvpair_free(nvp);
                nvp_buf_free(nvl, nvp);
                return (err);
        }
        nvp_buf_link(nvl, nvp);

        return (0);
}

int
nvlist_add_boolean(nvlist_t *nvl, const char *name)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_BOOLEAN, 0, NULL));
}

int
nvlist_add_boolean_value(nvlist_t *nvl, const char *name, boolean_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_BOOLEAN_VALUE, 1, &val));
}

int
nvlist_add_byte(nvlist_t *nvl, const char *name, uchar_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_BYTE, 1, &val));
}

int
nvlist_add_int8(nvlist_t *nvl, const char *name, int8_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT8, 1, &val));
}

int
nvlist_add_uint8(nvlist_t *nvl, const char *name, uint8_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT8, 1, &val));
}

int
nvlist_add_int16(nvlist_t *nvl, const char *name, int16_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT16, 1, &val));
}

int
nvlist_add_uint16(nvlist_t *nvl, const char *name, uint16_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT16, 1, &val));
}

int
nvlist_add_int32(nvlist_t *nvl, const char *name, int32_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT32, 1, &val));
}

int
nvlist_add_uint32(nvlist_t *nvl, const char *name, uint32_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT32, 1, &val));
}

int
nvlist_add_int64(nvlist_t *nvl, const char *name, int64_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT64, 1, &val));
}

int
nvlist_add_uint64(nvlist_t *nvl, const char *name, uint64_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT64, 1, &val));
}

#if !defined(_KERNEL)
int
nvlist_add_double(nvlist_t *nvl, const char *name, double val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_DOUBLE, 1, &val));
}
#endif

int
nvlist_add_string(nvlist_t *nvl, const char *name, const char *val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_STRING, 1, (void *)val));
}

int
nvlist_add_boolean_array(nvlist_t *nvl, const char *name,
    boolean_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_BOOLEAN_ARRAY, n, a));
}

int
nvlist_add_byte_array(nvlist_t *nvl, const char *name, uchar_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_BYTE_ARRAY, n, a));
}

int
nvlist_add_int8_array(nvlist_t *nvl, const char *name, int8_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT8_ARRAY, n, a));
}

int
nvlist_add_uint8_array(nvlist_t *nvl, const char *name, uint8_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT8_ARRAY, n, a));
}

int
nvlist_add_int16_array(nvlist_t *nvl, const char *name, int16_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT16_ARRAY, n, a));
}

int
nvlist_add_uint16_array(nvlist_t *nvl, const char *name, uint16_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT16_ARRAY, n, a));
}

int
nvlist_add_int32_array(nvlist_t *nvl, const char *name, int32_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT32_ARRAY, n, a));
}

int
nvlist_add_uint32_array(nvlist_t *nvl, const char *name, uint32_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT32_ARRAY, n, a));
}

int
nvlist_add_int64_array(nvlist_t *nvl, const char *name, int64_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_INT64_ARRAY, n, a));
}

int
nvlist_add_uint64_array(nvlist_t *nvl, const char *name, uint64_t *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_UINT64_ARRAY, n, a));
}

int
nvlist_add_string_array(nvlist_t *nvl, const char *name,
    char *const *a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_STRING_ARRAY, n, a));
}

int
nvlist_add_hrtime(nvlist_t *nvl, const char *name, hrtime_t val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_HRTIME, 1, &val));
}

int
nvlist_add_nvlist(nvlist_t *nvl, const char *name, nvlist_t *val)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_NVLIST, 1, val));
}

int
nvlist_add_nvlist_array(nvlist_t *nvl, const char *name, nvlist_t **a, uint_t n)
{
        return (nvlist_add_common(nvl, name, DATA_TYPE_NVLIST_ARRAY, n, a));
}

/* reading name-value pairs */
nvpair_t *
nvlist_next_nvpair(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv;
        i_nvp_t *curr;

        if (nvl == NULL ||
            (priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
                return (NULL);

        curr = NVPAIR2I_NVP(nvp);

        /*
         * Ensure that nvp is a valid nvpair on this nvlist.
         * NB: nvp_curr is used only as a hint so that we don't always
         * have to walk the list to determine if nvp is still on the list.
         */
        if (nvp == NULL)
                curr = priv->nvp_list;
        else if (priv->nvp_curr == curr || nvlist_contains_nvp(nvl, nvp))
                curr = curr->nvi_next;
        else
                curr = NULL;

        priv->nvp_curr = curr;

        return (curr != NULL ? &curr->nvi_nvp : NULL);
}

nvpair_t *
nvlist_prev_nvpair(nvlist_t *nvl, nvpair_t *nvp)
{
        nvpriv_t *priv;
        i_nvp_t *curr;

        if (nvl == NULL ||
            (priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
                return (NULL);

        curr = NVPAIR2I_NVP(nvp);

        if (nvp == NULL)
                curr = priv->nvp_last;
        else if (priv->nvp_curr == curr || nvlist_contains_nvp(nvl, nvp))
                curr = curr->nvi_prev;
        else
                curr = NULL;

        priv->nvp_curr = curr;

        return (curr != NULL ? &curr->nvi_nvp : NULL);
}

boolean_t
nvlist_empty(nvlist_t *nvl)
{
        nvpriv_t *priv;

        if (nvl == NULL ||
            (priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
                return (B_TRUE);

        return (priv->nvp_list == NULL);
}

char *
nvpair_name(nvpair_t *nvp)
{
        return (NVP_NAME(nvp));
}

data_type_t
nvpair_type(nvpair_t *nvp)
{
        return (NVP_TYPE(nvp));
}

int
nvpair_type_is_array(nvpair_t *nvp)
{
        data_type_t type = NVP_TYPE(nvp);

        if ((type == DATA_TYPE_BYTE_ARRAY) ||
            (type == DATA_TYPE_INT8_ARRAY) ||
            (type == DATA_TYPE_UINT8_ARRAY) ||
            (type == DATA_TYPE_INT16_ARRAY) ||
            (type == DATA_TYPE_UINT16_ARRAY) ||
            (type == DATA_TYPE_INT32_ARRAY) ||
            (type == DATA_TYPE_UINT32_ARRAY) ||
            (type == DATA_TYPE_INT64_ARRAY) ||
            (type == DATA_TYPE_UINT64_ARRAY) ||
            (type == DATA_TYPE_BOOLEAN_ARRAY) ||
            (type == DATA_TYPE_STRING_ARRAY) ||
            (type == DATA_TYPE_NVLIST_ARRAY))
                return (1);
        return (0);

}

static int
nvpair_value_common(nvpair_t *nvp, data_type_t type, uint_t *nelem, void *data)
{
        int value_sz;

        if (nvp == NULL || nvpair_type(nvp) != type)
                return (EINVAL);

        /*
         * For non-array types, we copy the data.
         * For array types (including string), we set a pointer.
         */
        switch (type) {
        case DATA_TYPE_BOOLEAN:
                if (nelem != NULL)
                        *nelem = 0;
                break;

        case DATA_TYPE_BOOLEAN_VALUE:
        case DATA_TYPE_BYTE:
        case DATA_TYPE_INT8:
        case DATA_TYPE_UINT8:
        case DATA_TYPE_INT16:
        case DATA_TYPE_UINT16:
        case DATA_TYPE_INT32:
        case DATA_TYPE_UINT32:
        case DATA_TYPE_INT64:
        case DATA_TYPE_UINT64:
        case DATA_TYPE_HRTIME:
#if !defined(_KERNEL)
        case DATA_TYPE_DOUBLE:
#endif
                if (data == NULL)
                        return (EINVAL);
                if ((value_sz = i_get_value_size(type, NULL, 1)) < 0)
                        return (EINVAL);
                bcopy(NVP_VALUE(nvp), data, (size_t)value_sz);
                if (nelem != NULL)
                        *nelem = 1;
                break;

        case DATA_TYPE_NVLIST:
        case DATA_TYPE_STRING:
                if (data == NULL)
                        return (EINVAL);
                *(void **)data = (void *)NVP_VALUE(nvp);
                if (nelem != NULL)
                        *nelem = 1;
                break;

        case DATA_TYPE_BOOLEAN_ARRAY:
        case DATA_TYPE_BYTE_ARRAY:
        case DATA_TYPE_INT8_ARRAY:
        case DATA_TYPE_UINT8_ARRAY:
        case DATA_TYPE_INT16_ARRAY:
        case DATA_TYPE_UINT16_ARRAY:
        case DATA_TYPE_INT32_ARRAY:
        case DATA_TYPE_UINT32_ARRAY:
        case DATA_TYPE_INT64_ARRAY:
        case DATA_TYPE_UINT64_ARRAY:
        case DATA_TYPE_STRING_ARRAY:
        case DATA_TYPE_NVLIST_ARRAY:
                if (nelem == NULL || data == NULL)
                        return (EINVAL);
                if ((*nelem = NVP_NELEM(nvp)) != 0)
                        *(void **)data = (void *)NVP_VALUE(nvp);
                else
                        *(void **)data = NULL;
                break;

        default:
                return (ENOTSUP);
        }

        return (0);
}

static int
nvlist_lookup_common(nvlist_t *nvl, const char *name, data_type_t type,
    uint_t *nelem, void *data)
{
        if (name == NULL || nvl == NULL || nvl->nvl_priv == 0)
                return (EINVAL);

        if (!(nvl->nvl_nvflag & (NV_UNIQUE_NAME | NV_UNIQUE_NAME_TYPE)))
                return (ENOTSUP);

        nvpair_t *nvp = nvt_lookup_name_type(nvl, name, type);
        if (nvp == NULL)
                return (ENOENT);

        return (nvpair_value_common(nvp, type, nelem, data));
}

int
nvlist_lookup_boolean(nvlist_t *nvl, const char *name)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_BOOLEAN, NULL, NULL));
}

int
nvlist_lookup_boolean_value(nvlist_t *nvl, const char *name, boolean_t *val)
{
        return (nvlist_lookup_common(nvl, name,
            DATA_TYPE_BOOLEAN_VALUE, NULL, val));
}

int
nvlist_lookup_byte(nvlist_t *nvl, const char *name, uchar_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_BYTE, NULL, val));
}

int
nvlist_lookup_int8(nvlist_t *nvl, const char *name, int8_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT8, NULL, val));
}

int
nvlist_lookup_uint8(nvlist_t *nvl, const char *name, uint8_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT8, NULL, val));
}

int
nvlist_lookup_int16(nvlist_t *nvl, const char *name, int16_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT16, NULL, val));
}

int
nvlist_lookup_uint16(nvlist_t *nvl, const char *name, uint16_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT16, NULL, val));
}

int
nvlist_lookup_int32(nvlist_t *nvl, const char *name, int32_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT32, NULL, val));
}

int
nvlist_lookup_uint32(nvlist_t *nvl, const char *name, uint32_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT32, NULL, val));
}

int
nvlist_lookup_int64(nvlist_t *nvl, const char *name, int64_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT64, NULL, val));
}

int
nvlist_lookup_uint64(nvlist_t *nvl, const char *name, uint64_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT64, NULL, val));
}

#if !defined(_KERNEL)
int
nvlist_lookup_double(nvlist_t *nvl, const char *name, double *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_DOUBLE, NULL, val));
}
#endif

int
nvlist_lookup_string(nvlist_t *nvl, const char *name, char **val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_STRING, NULL, val));
}

int
nvlist_lookup_nvlist(nvlist_t *nvl, const char *name, nvlist_t **val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_NVLIST, NULL, val));
}

int
nvlist_lookup_boolean_array(nvlist_t *nvl, const char *name,
    boolean_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name,
            DATA_TYPE_BOOLEAN_ARRAY, n, a));
}

int
nvlist_lookup_byte_array(nvlist_t *nvl, const char *name,
    uchar_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_BYTE_ARRAY, n, a));
}

int
nvlist_lookup_int8_array(nvlist_t *nvl, const char *name, int8_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT8_ARRAY, n, a));
}

int
nvlist_lookup_uint8_array(nvlist_t *nvl, const char *name,
    uint8_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT8_ARRAY, n, a));
}

int
nvlist_lookup_int16_array(nvlist_t *nvl, const char *name,
    int16_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT16_ARRAY, n, a));
}

int
nvlist_lookup_uint16_array(nvlist_t *nvl, const char *name,
    uint16_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT16_ARRAY, n, a));
}

int
nvlist_lookup_int32_array(nvlist_t *nvl, const char *name,
    int32_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT32_ARRAY, n, a));
}

int
nvlist_lookup_uint32_array(nvlist_t *nvl, const char *name,
    uint32_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT32_ARRAY, n, a));
}

int
nvlist_lookup_int64_array(nvlist_t *nvl, const char *name,
    int64_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_INT64_ARRAY, n, a));
}

int
nvlist_lookup_uint64_array(nvlist_t *nvl, const char *name,
    uint64_t **a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT64_ARRAY, n, a));
}

int
nvlist_lookup_string_array(nvlist_t *nvl, const char *name,
    char ***a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_STRING_ARRAY, n, a));
}

int
nvlist_lookup_nvlist_array(nvlist_t *nvl, const char *name,
    nvlist_t ***a, uint_t *n)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_NVLIST_ARRAY, n, a));
}

int
nvlist_lookup_hrtime(nvlist_t *nvl, const char *name, hrtime_t *val)
{
        return (nvlist_lookup_common(nvl, name, DATA_TYPE_HRTIME, NULL, val));
}

int
nvlist_lookup_pairs(nvlist_t *nvl, int flag, ...)
{
        va_list ap;
        char *name;
        int noentok = (flag & NV_FLAG_NOENTOK ? 1 : 0);
        int ret = 0;

        va_start(ap, flag);
        while (ret == 0 && (name = va_arg(ap, char *)) != NULL) {
                data_type_t type;
                void *val;
                uint_t *nelem;

                switch (type = va_arg(ap, data_type_t)) {
                case DATA_TYPE_BOOLEAN:
                        ret = nvlist_lookup_common(nvl, name, type, NULL, NULL);
                        break;

                case DATA_TYPE_BOOLEAN_VALUE:
                case DATA_TYPE_BYTE:
                case DATA_TYPE_INT8:
                case DATA_TYPE_UINT8:
                case DATA_TYPE_INT16:
                case DATA_TYPE_UINT16:
                case DATA_TYPE_INT32:
                case DATA_TYPE_UINT32:
                case DATA_TYPE_INT64:
                case DATA_TYPE_UINT64:
                case DATA_TYPE_HRTIME:
                case DATA_TYPE_STRING:
                case DATA_TYPE_NVLIST:
#if !defined(_KERNEL)
                case DATA_TYPE_DOUBLE:
#endif
                        val = va_arg(ap, void *);
                        ret = nvlist_lookup_common(nvl, name, type, NULL, val);
                        break;

                case DATA_TYPE_BYTE_ARRAY:
                case DATA_TYPE_BOOLEAN_ARRAY:
                case DATA_TYPE_INT8_ARRAY:
                case DATA_TYPE_UINT8_ARRAY:
                case DATA_TYPE_INT16_ARRAY:
                case DATA_TYPE_UINT16_ARRAY:
                case DATA_TYPE_INT32_ARRAY:
                case DATA_TYPE_UINT32_ARRAY:
                case DATA_TYPE_INT64_ARRAY:
                case DATA_TYPE_UINT64_ARRAY:
                case DATA_TYPE_STRING_ARRAY:
                case DATA_TYPE_NVLIST_ARRAY:
                        val = va_arg(ap, void *);
                        nelem = va_arg(ap, uint_t *);
                        ret = nvlist_lookup_common(nvl, name, type, nelem, val);
                        break;

                default:
                        ret = EINVAL;
                }

                if (ret == ENOENT && noentok)
                        ret = 0;
        }
        va_end(ap);

        return (ret);
}

/*
 * Find the 'name'ed nvpair in the nvlist 'nvl'. If 'name' found, the function
 * returns zero and a pointer to the matching nvpair is returned in '*ret'
 * (given 'ret' is non-NULL). If 'sep' is specified then 'name' will penitrate
 * multiple levels of embedded nvlists, with 'sep' as the separator. As an
 * example, if sep is '.', name might look like: "a" or "a.b" or "a.c[3]" or
 * "a.d[3].e[1]".  This matches the C syntax for array embed (for convience,
 * code also supports "a.d[3]e[1]" syntax).
 *
 * If 'ip' is non-NULL and the last name component is an array, return the
 * value of the "...[index]" array index in *ip. For an array reference that
 * is not indexed, *ip will be returned as -1. If there is a syntax error in
 * 'name', and 'ep' is non-NULL then *ep will be set to point to the location
 * inside the 'name' string where the syntax error was detected.
 */
static int
nvlist_lookup_nvpair_ei_sep(nvlist_t *nvl, const char *name, const char sep,
    nvpair_t **ret, int *ip, char **ep)
{
        nvpair_t        *nvp;
        const char      *np;
        char            *sepp = NULL;
        char            *idxp, *idxep;
        nvlist_t        **nva;
        long            idx = 0;
        int             n;

        if (ip)
                *ip = -1;                       /* not indexed */
        if (ep)
                *ep = NULL;

        if ((nvl == NULL) || (name == NULL))
                return (EINVAL);

        sepp = NULL;
        idx = 0;
        /* step through components of name */
        for (np = name; np && *np; np = sepp) {
                /* ensure unique names */
                if (!(nvl->nvl_nvflag & NV_UNIQUE_NAME))
                        return (ENOTSUP);

                /* skip white space */
                skip_whitespace(np);
                if (*np == 0)
                        break;

                /* set 'sepp' to end of current component 'np' */
                if (sep)
                        sepp = strchr(np, sep);
                else
                        sepp = NULL;

                /* find start of next "[ index ]..." */
                idxp = strchr(np, '[');

                /* if sepp comes first, set idxp to NULL */
                if (sepp && idxp && (sepp < idxp))
                        idxp = NULL;

                /*
                 * At this point 'idxp' is set if there is an index
                 * expected for the current component.
                 */
                if (idxp) {
                        /* set 'n' to length of current 'np' name component */
                        n = idxp++ - np;

                        /* keep sepp up to date for *ep use as we advance */
                        skip_whitespace(idxp);
                        sepp = idxp;

                        /* determine the index value */
#if defined(_KERNEL)
                        if (ddi_strtol(idxp, &idxep, 0, &idx))
                                goto fail;
#else
                        idx = strtol(idxp, &idxep, 0);
#endif
                        if (idxep == idxp)
                                goto fail;

                        /* keep sepp up to date for *ep use as we advance */
                        sepp = idxep;

                        /* skip white space index value and check for ']' */
                        skip_whitespace(sepp);
                        if (*sepp++ != ']')
                                goto fail;

                        /* for embedded arrays, support C syntax: "a[1].b" */
                        skip_whitespace(sepp);
                        if (sep && (*sepp == sep))
                                sepp++;
                } else if (sepp) {
                        n = sepp++ - np;
                } else {
                        n = strlen(np);
                }

                /* trim trailing whitespace by reducing length of 'np' */
                if (n == 0)
                        goto fail;
                for (n--; (np[n] == ' ') || (np[n] == '\t'); n--)
                        ;
                n++;

                /* skip whitespace, and set sepp to NULL if complete */
                if (sepp) {
                        skip_whitespace(sepp);
                        if (*sepp == 0)
                                sepp = NULL;
                }

                /*
                 * At this point:
                 * o  'n' is the length of current 'np' component.
                 * o  'idxp' is set if there was an index, and value 'idx'.
                 * o  'sepp' is set to the beginning of the next component,
                 *    and set to NULL if we have no more components.
                 *
                 * Search for nvpair with matching component name.
                 */
                for (nvp = nvlist_next_nvpair(nvl, NULL); nvp != NULL;
                    nvp = nvlist_next_nvpair(nvl, nvp)) {

                        /* continue if no match on name */
                        if (strncmp(np, nvpair_name(nvp), n) ||
                            (strlen(nvpair_name(nvp)) != n))
                                continue;

                        /* if indexed, verify type is array oriented */
                        if (idxp && !nvpair_type_is_array(nvp))
                                goto fail;

                        /*
                         * Full match found, return nvp and idx if this
                         * was the last component.
                         */
                        if (sepp == NULL) {
                                if (ret)
                                        *ret = nvp;
                                if (ip && idxp)
                                        *ip = (int)idx; /* return index */
                                return (0);             /* found */
                        }

                        /*
                         * More components: current match must be
                         * of DATA_TYPE_NVLIST or DATA_TYPE_NVLIST_ARRAY
                         * to support going deeper.
                         */
                        if (nvpair_type(nvp) == DATA_TYPE_NVLIST) {
                                nvl = EMBEDDED_NVL(nvp);
                                break;
                        } else if (nvpair_type(nvp) == DATA_TYPE_NVLIST_ARRAY) {
                                (void) nvpair_value_nvlist_array(nvp,
                                    &nva, (uint_t *)&n);
                                if ((n < 0) || (idx >= n))
                                        goto fail;
                                nvl = nva[idx];
                                break;
                        }

                        /* type does not support more levels */
                        goto fail;
                }
                if (nvp == NULL)
                        goto fail;              /* 'name' not found */

                /* search for match of next component in embedded 'nvl' list */
        }

fail:   if (ep && sepp)
                *ep = sepp;
        return (EINVAL);
}

/*
 * Return pointer to nvpair with specified 'name'.
 */
int
nvlist_lookup_nvpair(nvlist_t *nvl, const char *name, nvpair_t **ret)
{
        return (nvlist_lookup_nvpair_ei_sep(nvl, name, 0, ret, NULL, NULL));
}

/*
 * Determine if named nvpair exists in nvlist (use embedded separator of '.'
 * and return array index).  See nvlist_lookup_nvpair_ei_sep for more detailed
 * description.
 */
int nvlist_lookup_nvpair_embedded_index(nvlist_t *nvl,
    const char *name, nvpair_t **ret, int *ip, char **ep)
{
        return (nvlist_lookup_nvpair_ei_sep(nvl, name, '.', ret, ip, ep));
}

boolean_t
nvlist_exists(nvlist_t *nvl, const char *name)
{
        nvpriv_t *priv;
        nvpair_t *nvp;
        i_nvp_t *curr;

        if (name == NULL || nvl == NULL ||
            (priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
                return (B_FALSE);

        for (curr = priv->nvp_list; curr != NULL; curr = curr->nvi_next) {
                nvp = &curr->nvi_nvp;

                if (strcmp(name, NVP_NAME(nvp)) == 0)
                        return (B_TRUE);
        }

        return (B_FALSE);
}

int
nvpair_value_boolean_value(nvpair_t *nvp, boolean_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_BOOLEAN_VALUE, NULL, val));
}

int
nvpair_value_byte(nvpair_t *nvp, uchar_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_BYTE, NULL, val));
}

int
nvpair_value_int8(nvpair_t *nvp, int8_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT8, NULL, val));
}

int
nvpair_value_uint8(nvpair_t *nvp, uint8_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT8, NULL, val));
}

int
nvpair_value_int16(nvpair_t *nvp, int16_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT16, NULL, val));
}

int
nvpair_value_uint16(nvpair_t *nvp, uint16_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT16, NULL, val));
}

int
nvpair_value_int32(nvpair_t *nvp, int32_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT32, NULL, val));
}

int
nvpair_value_uint32(nvpair_t *nvp, uint32_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT32, NULL, val));
}

int
nvpair_value_int64(nvpair_t *nvp, int64_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT64, NULL, val));
}

int
nvpair_value_uint64(nvpair_t *nvp, uint64_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT64, NULL, val));
}

#if !defined(_KERNEL)
int
nvpair_value_double(nvpair_t *nvp, double *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_DOUBLE, NULL, val));
}
#endif

int
nvpair_value_string(nvpair_t *nvp, char **val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_STRING, NULL, val));
}

int
nvpair_value_nvlist(nvpair_t *nvp, nvlist_t **val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_NVLIST, NULL, val));
}

int
nvpair_value_boolean_array(nvpair_t *nvp, boolean_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_BOOLEAN_ARRAY, nelem, val));
}

int
nvpair_value_byte_array(nvpair_t *nvp, uchar_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_BYTE_ARRAY, nelem, val));
}

int
nvpair_value_int8_array(nvpair_t *nvp, int8_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT8_ARRAY, nelem, val));
}

int
nvpair_value_uint8_array(nvpair_t *nvp, uint8_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT8_ARRAY, nelem, val));
}

int
nvpair_value_int16_array(nvpair_t *nvp, int16_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT16_ARRAY, nelem, val));
}

int
nvpair_value_uint16_array(nvpair_t *nvp, uint16_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT16_ARRAY, nelem, val));
}

int
nvpair_value_int32_array(nvpair_t *nvp, int32_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT32_ARRAY, nelem, val));
}

int
nvpair_value_uint32_array(nvpair_t *nvp, uint32_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT32_ARRAY, nelem, val));
}

int
nvpair_value_int64_array(nvpair_t *nvp, int64_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_INT64_ARRAY, nelem, val));
}

int
nvpair_value_uint64_array(nvpair_t *nvp, uint64_t **val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_UINT64_ARRAY, nelem, val));
}

int
nvpair_value_string_array(nvpair_t *nvp, char ***val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_STRING_ARRAY, nelem, val));
}

int
nvpair_value_nvlist_array(nvpair_t *nvp, nvlist_t ***val, uint_t *nelem)
{
        return (nvpair_value_common(nvp, DATA_TYPE_NVLIST_ARRAY, nelem, val));
}

int
nvpair_value_hrtime(nvpair_t *nvp, hrtime_t *val)
{
        return (nvpair_value_common(nvp, DATA_TYPE_HRTIME, NULL, val));
}

/*
 * Add specified pair to the list.
 */
int
nvlist_add_nvpair(nvlist_t *nvl, nvpair_t *nvp)
{
        if (nvl == NULL || nvp == NULL)
                return (EINVAL);

        return (nvlist_add_common(nvl, NVP_NAME(nvp), NVP_TYPE(nvp),
            NVP_NELEM(nvp), NVP_VALUE(nvp)));
}

/*
 * Merge the supplied nvlists and put the result in dst.
 * The merged list will contain all names specified in both lists,
 * the values are taken from nvl in the case of duplicates.
 * Return 0 on success.
 */
/*ARGSUSED*/
int
nvlist_merge(nvlist_t *dst, nvlist_t *nvl, int flag)
{
        if (nvl == NULL || dst == NULL)
                return (EINVAL);

        if (dst != nvl)
                return (nvlist_copy_pairs(nvl, dst));

        return (0);
}

/*
 * Encoding related routines
 */
#define NVS_OP_ENCODE   0
#define NVS_OP_DECODE   1
#define NVS_OP_GETSIZE  2

typedef struct nvs_ops nvs_ops_t;

typedef struct {
        int             nvs_op;
        const nvs_ops_t *nvs_ops;
        void            *nvs_private;
        nvpriv_t        *nvs_priv;
        int             nvs_recursion;
} nvstream_t;

/*
 * nvs operations are:
 *   - nvs_nvlist
 *     encoding / decoding of an nvlist header (nvlist_t)
 *     calculates the size used for header and end detection
 *
 *   - nvs_nvpair
 *     responsible for the first part of encoding / decoding of an nvpair
 *     calculates the decoded size of an nvpair
 *
 *   - nvs_nvp_op
 *     second part of encoding / decoding of an nvpair
 *
 *   - nvs_nvp_size
 *     calculates the encoding size of an nvpair
 *
 *   - nvs_nvl_fini
 *     encodes the end detection mark (zeros).
 */
struct nvs_ops {
        int (*nvs_nvlist)(nvstream_t *, nvlist_t *, size_t *);
        int (*nvs_nvpair)(nvstream_t *, nvpair_t *, size_t *);
        int (*nvs_nvp_op)(nvstream_t *, nvpair_t *);
        int (*nvs_nvp_size)(nvstream_t *, nvpair_t *, size_t *);
        int (*nvs_nvl_fini)(nvstream_t *);
};

typedef struct {
        char    nvh_encoding;   /* nvs encoding method */
        char    nvh_endian;     /* nvs endian */
        char    nvh_reserved1;  /* reserved for future use */
        char    nvh_reserved2;  /* reserved for future use */
} nvs_header_t;

static int
nvs_encode_pairs(nvstream_t *nvs, nvlist_t *nvl)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        i_nvp_t *curr;

        /*
         * Walk nvpair in list and encode each nvpair
         */
        for (curr = priv->nvp_list; curr != NULL; curr = curr->nvi_next)
                if (nvs->nvs_ops->nvs_nvpair(nvs, &curr->nvi_nvp, NULL) != 0)
                        return (EFAULT);

        return (nvs->nvs_ops->nvs_nvl_fini(nvs));
}

static int
nvs_decode_pairs(nvstream_t *nvs, nvlist_t *nvl)
{
        nvpair_t *nvp;
        size_t nvsize;
        int err;

        /*
         * Get decoded size of next pair in stream, alloc
         * memory for nvpair_t, then decode the nvpair
         */
        while ((err = nvs->nvs_ops->nvs_nvpair(nvs, NULL, &nvsize)) == 0) {
                if (nvsize == 0) /* end of list */
                        break;

                /* make sure len makes sense */
                if (nvsize < NVP_SIZE_CALC(1, 0))
                        return (EFAULT);

                if ((nvp = nvp_buf_alloc(nvl, nvsize)) == NULL)
                        return (ENOMEM);

                if ((err = nvs->nvs_ops->nvs_nvp_op(nvs, nvp)) != 0) {
                        nvp_buf_free(nvl, nvp);
                        return (err);
                }

                if (i_validate_nvpair(nvp) != 0) {
                        nvpair_free(nvp);
                        nvp_buf_free(nvl, nvp);
                        return (EFAULT);
                }

                err = nvt_add_nvpair(nvl, nvp);
                if (err != 0) {
                        nvpair_free(nvp);
                        nvp_buf_free(nvl, nvp);
                        return (err);
                }
                nvp_buf_link(nvl, nvp);
        }
        return (err);
}

static int
nvs_getsize_pairs(nvstream_t *nvs, nvlist_t *nvl, size_t *buflen)
{
        nvpriv_t *priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv;
        i_nvp_t *curr;
        uint64_t nvsize = *buflen;
        size_t size;

        /*
         * Get encoded size of nvpairs in nvlist
         */
        for (curr = priv->nvp_list; curr != NULL; curr = curr->nvi_next) {
                if (nvs->nvs_ops->nvs_nvp_size(nvs, &curr->nvi_nvp, &size) != 0)
                        return (EINVAL);

                if ((nvsize += size) > INT32_MAX)
                        return (EINVAL);
        }

        *buflen = nvsize;
        return (0);
}

static int
nvs_operation(nvstream_t *nvs, nvlist_t *nvl, size_t *buflen)
{
        int err;

        if (nvl->nvl_priv == 0)
                return (EFAULT);

        /*
         * Perform the operation, starting with header, then each nvpair
         */
        if ((err = nvs->nvs_ops->nvs_nvlist(nvs, nvl, buflen)) != 0)
                return (err);

        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
                err = nvs_encode_pairs(nvs, nvl);
                break;

        case NVS_OP_DECODE:
                err = nvs_decode_pairs(nvs, nvl);
                break;

        case NVS_OP_GETSIZE:
                err = nvs_getsize_pairs(nvs, nvl, buflen);
                break;

        default:
                err = EINVAL;
        }

        return (err);
}

static int
nvs_embedded(nvstream_t *nvs, nvlist_t *embedded)
{
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE: {
                int err;

                if (nvs->nvs_recursion >= nvpair_max_recursion)
                        return (EINVAL);
                nvs->nvs_recursion++;
                err = nvs_operation(nvs, embedded, NULL);
                nvs->nvs_recursion--;
                return (err);
        }
        case NVS_OP_DECODE: {
                nvpriv_t *priv;
                int err;

                if (embedded->nvl_version != NV_VERSION)
                        return (ENOTSUP);

                if ((priv = nv_priv_alloc_embedded(nvs->nvs_priv)) == NULL)
                        return (ENOMEM);

                nvlist_init(embedded, embedded->nvl_nvflag, priv);

                if (nvs->nvs_recursion >= nvpair_max_recursion) {
                        nvlist_free(embedded);
                        return (EINVAL);
                }
                nvs->nvs_recursion++;
                if ((err = nvs_operation(nvs, embedded, NULL)) != 0)
                        nvlist_free(embedded);
                nvs->nvs_recursion--;
                return (err);
        }
        default:
                break;
        }

        return (EINVAL);
}

static int
nvs_embedded_nvl_array(nvstream_t *nvs, nvpair_t *nvp, size_t *size)
{
        size_t nelem = NVP_NELEM(nvp);
        nvlist_t **nvlp = EMBEDDED_NVL_ARRAY(nvp);
        int i;

        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
                for (i = 0; i < nelem; i++)
                        if (nvs_embedded(nvs, nvlp[i]) != 0)
                                return (EFAULT);
                break;

        case NVS_OP_DECODE: {
                size_t len = nelem * sizeof (uint64_t);
                nvlist_t *embedded = (nvlist_t *)((uintptr_t)nvlp + len);

                bzero(nvlp, len);       /* don't trust packed data */
                for (i = 0; i < nelem; i++) {
                        if (nvs_embedded(nvs, embedded) != 0) {
                                nvpair_free(nvp);
                                return (EFAULT);
                        }

                        nvlp[i] = embedded++;
                }
                break;
        }
        case NVS_OP_GETSIZE: {
                uint64_t nvsize = 0;

                for (i = 0; i < nelem; i++) {
                        size_t nvp_sz = 0;

                        if (nvs_operation(nvs, nvlp[i], &nvp_sz) != 0)
                                return (EINVAL);

                        if ((nvsize += nvp_sz) > INT32_MAX)
                                return (EINVAL);
                }

                *size = nvsize;
                break;
        }
        default:
                return (EINVAL);
        }

        return (0);
}

static int nvs_native(nvstream_t *, nvlist_t *, char *, size_t *);
static int nvs_xdr(nvstream_t *, nvlist_t *, char *, size_t *);

/*
 * Common routine for nvlist operations:
 * encode, decode, getsize (encoded size).
 */
static int
nvlist_common(nvlist_t *nvl, char *buf, size_t *buflen, int encoding,
    int nvs_op)
{
        int err = 0;
        nvstream_t nvs;
        int nvl_endian;
#ifdef  _LITTLE_ENDIAN
        int host_endian = 1;
#else
        int host_endian = 0;
#endif  /* _LITTLE_ENDIAN */
        nvs_header_t *nvh = (void *)buf;

        if (buflen == NULL || nvl == NULL ||
            (nvs.nvs_priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
                return (EINVAL);

        nvs.nvs_op = nvs_op;
        nvs.nvs_recursion = 0;

        /*
         * For NVS_OP_ENCODE and NVS_OP_DECODE make sure an nvlist and
         * a buffer is allocated.  The first 4 bytes in the buffer are
         * used for encoding method and host endian.
         */
        switch (nvs_op) {
        case NVS_OP_ENCODE:
                if (buf == NULL || *buflen < sizeof (nvs_header_t))
                        return (EINVAL);

                nvh->nvh_encoding = encoding;
                nvh->nvh_endian = nvl_endian = host_endian;
                nvh->nvh_reserved1 = 0;
                nvh->nvh_reserved2 = 0;
                break;

        case NVS_OP_DECODE:
                if (buf == NULL || *buflen < sizeof (nvs_header_t))
                        return (EINVAL);

                /* get method of encoding from first byte */
                encoding = nvh->nvh_encoding;
                nvl_endian = nvh->nvh_endian;
                break;

        case NVS_OP_GETSIZE:
                nvl_endian = host_endian;

                /*
                 * add the size for encoding
                 */
                *buflen = sizeof (nvs_header_t);
                break;

        default:
                return (ENOTSUP);
        }

        /*
         * Create an nvstream with proper encoding method
         */
        switch (encoding) {
        case NV_ENCODE_NATIVE:
                /*
                 * check endianness, in case we are unpacking
                 * from a file
                 */
                if (nvl_endian != host_endian)
                        return (ENOTSUP);
                err = nvs_native(&nvs, nvl, buf, buflen);
                break;
        case NV_ENCODE_XDR:
                err = nvs_xdr(&nvs, nvl, buf, buflen);
                break;
        default:
                err = ENOTSUP;
                break;
        }

        return (err);
}

int
nvlist_size(nvlist_t *nvl, size_t *size, int encoding)
{
        return (nvlist_common(nvl, NULL, size, encoding, NVS_OP_GETSIZE));
}

/*
 * Pack nvlist into contiguous memory
 */
int
nvlist_pack(nvlist_t *nvl, char **bufp, size_t *buflen, int encoding,
    int kmflag)
{
        return (nvlist_xpack(nvl, bufp, buflen, encoding,
            nvlist_nv_alloc(kmflag)));
}

int
nvlist_xpack(nvlist_t *nvl, char **bufp, size_t *buflen, int encoding,
    nv_alloc_t *nva)
{
        nvpriv_t nvpriv;
        size_t alloc_size;
        char *buf;
        int err;

        if (nva == NULL || nvl == NULL || bufp == NULL || buflen == NULL)
                return (EINVAL);

        if (*bufp != NULL)
                return (nvlist_common(nvl, *bufp, buflen, encoding,
                    NVS_OP_ENCODE));

        /*
         * Here is a difficult situation:
         * 1. The nvlist has fixed allocator properties.
         *    All other nvlist routines (like nvlist_add_*, ...) use
         *    these properties.
         * 2. When using nvlist_pack() the user can specify their own
         *    allocator properties (e.g. by using KM_NOSLEEP).
         *
         * We use the user specified properties (2). A clearer solution
         * will be to remove the kmflag from nvlist_pack(), but we will
         * not change the interface.
         */
        nv_priv_init(&nvpriv, nva, 0);

        if ((err = nvlist_size(nvl, &alloc_size, encoding)))
                return (err);

        if ((buf = nv_mem_zalloc(&nvpriv, alloc_size)) == NULL)
                return (ENOMEM);

        if ((err = nvlist_common(nvl, buf, &alloc_size, encoding,
            NVS_OP_ENCODE)) != 0) {
                nv_mem_free(&nvpriv, buf, alloc_size);
        } else {
                *buflen = alloc_size;
                *bufp = buf;
        }

        return (err);
}

/*
 * Unpack buf into an nvlist_t
 */
int
nvlist_unpack(char *buf, size_t buflen, nvlist_t **nvlp, int kmflag)
{
        return (nvlist_xunpack(buf, buflen, nvlp, nvlist_nv_alloc(kmflag)));
}

int
nvlist_xunpack(char *buf, size_t buflen, nvlist_t **nvlp, nv_alloc_t *nva)
{
        nvlist_t *nvl;
        int err;

        if (nvlp == NULL)
                return (EINVAL);

        if ((err = nvlist_xalloc(&nvl, 0, nva)) != 0)
                return (err);

        if ((err = nvlist_common(nvl, buf, &buflen, NV_ENCODE_NATIVE,
            NVS_OP_DECODE)) != 0)
                nvlist_free(nvl);
        else
                *nvlp = nvl;

        return (err);
}

/*
 * Native encoding functions
 */
typedef struct {
        /*
         * This structure is used when decoding a packed nvpair in
         * the native format.  n_base points to a buffer containing the
         * packed nvpair.  n_end is a pointer to the end of the buffer.
         * (n_end actually points to the first byte past the end of the
         * buffer.)  n_curr is a pointer that lies between n_base and n_end.
         * It points to the current data that we are decoding.
         * The amount of data left in the buffer is equal to n_end - n_curr.
         * n_flag is used to recognize a packed embedded list.
         */
        caddr_t n_base;
        caddr_t n_end;
        caddr_t n_curr;
        uint_t  n_flag;
} nvs_native_t;

static int
nvs_native_create(nvstream_t *nvs, nvs_native_t *native, char *buf,
    size_t buflen)
{
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
        case NVS_OP_DECODE:
                nvs->nvs_private = native;
                native->n_curr = native->n_base = buf;
                native->n_end = buf + buflen;
                native->n_flag = 0;
                return (0);

        case NVS_OP_GETSIZE:
                nvs->nvs_private = native;
                native->n_curr = native->n_base = native->n_end = NULL;
                native->n_flag = 0;
                return (0);
        default:
                return (EINVAL);
        }
}

/*ARGSUSED*/
static void
nvs_native_destroy(nvstream_t *nvs)
{
}

static int
native_cp(nvstream_t *nvs, void *buf, size_t size)
{
        nvs_native_t *native = (nvs_native_t *)nvs->nvs_private;

        if (native->n_curr + size > native->n_end)
                return (EFAULT);

        /*
         * The bcopy() below eliminates alignment requirement
         * on the buffer (stream) and is preferred over direct access.
         */
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
                bcopy(buf, native->n_curr, size);
                break;
        case NVS_OP_DECODE:
                bcopy(native->n_curr, buf, size);
                break;
        default:
                return (EINVAL);
        }

        native->n_curr += size;
        return (0);
}

/*
 * operate on nvlist_t header
 */
static int
nvs_native_nvlist(nvstream_t *nvs, nvlist_t *nvl, size_t *size)
{
        nvs_native_t *native = nvs->nvs_private;

        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
        case NVS_OP_DECODE:
                if (native->n_flag)
                        return (0);     /* packed embedded list */

                native->n_flag = 1;

                /* copy version and nvflag of the nvlist_t */
                if (native_cp(nvs, &nvl->nvl_version, sizeof (int32_t)) != 0 ||
                    native_cp(nvs, &nvl->nvl_nvflag, sizeof (int32_t)) != 0)
                        return (EFAULT);

                return (0);

        case NVS_OP_GETSIZE:
                /*
                 * if calculate for packed embedded list
                 *      4 for end of the embedded list
                 * else
                 *      2 * sizeof (int32_t) for nvl_version and nvl_nvflag
                 *      and 4 for end of the entire list
                 */
                if (native->n_flag) {
                        *size += 4;
                } else {
                        native->n_flag = 1;
                        *size += 2 * sizeof (int32_t) + 4;
                }

                return (0);

        default:
                return (EINVAL);
        }
}

static int
nvs_native_nvl_fini(nvstream_t *nvs)
{
        if (nvs->nvs_op == NVS_OP_ENCODE) {
                nvs_native_t *native = (nvs_native_t *)nvs->nvs_private;
                /*
                 * Add 4 zero bytes at end of nvlist. They are used
                 * for end detection by the decode routine.
                 */
                if (native->n_curr + sizeof (int) > native->n_end)
                        return (EFAULT);

                bzero(native->n_curr, sizeof (int));
                native->n_curr += sizeof (int);
        }

        return (0);
}

static int
nvpair_native_embedded(nvstream_t *nvs, nvpair_t *nvp)
{
        if (nvs->nvs_op == NVS_OP_ENCODE) {
                nvs_native_t *native = (nvs_native_t *)nvs->nvs_private;
                nvlist_t *packed = (void *)
                    (native->n_curr - nvp->nvp_size + NVP_VALOFF(nvp));
                /*
                 * Null out the pointer that is meaningless in the packed
                 * structure. The address may not be aligned, so we have
                 * to use bzero.
                 */
                bzero((char *)packed + offsetof(nvlist_t, nvl_priv),
                    sizeof (uint64_t));
        }

        return (nvs_embedded(nvs, EMBEDDED_NVL(nvp)));
}

static int
nvpair_native_embedded_array(nvstream_t *nvs, nvpair_t *nvp)
{
        if (nvs->nvs_op == NVS_OP_ENCODE) {
                nvs_native_t *native = (nvs_native_t *)nvs->nvs_private;
                char *value = native->n_curr - nvp->nvp_size + NVP_VALOFF(nvp);
                size_t len = NVP_NELEM(nvp) * sizeof (uint64_t);
                nvlist_t *packed = (nvlist_t *)((uintptr_t)value + len);
                int i;
                /*
                 * Null out pointers that are meaningless in the packed
                 * structure. The addresses may not be aligned, so we have
                 * to use bzero.
                 */
                bzero(value, len);

                for (i = 0; i < NVP_NELEM(nvp); i++, packed++)
                        /*
                         * Null out the pointer that is meaningless in the
                         * packed structure. The address may not be aligned,
                         * so we have to use bzero.
                         */
                        bzero((char *)packed + offsetof(nvlist_t, nvl_priv),
                            sizeof (uint64_t));
        }

        return (nvs_embedded_nvl_array(nvs, nvp, NULL));
}

static void
nvpair_native_string_array(nvstream_t *nvs, nvpair_t *nvp)
{
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE: {
                nvs_native_t *native = (nvs_native_t *)nvs->nvs_private;
                uint64_t *strp = (void *)
                    (native->n_curr - nvp->nvp_size + NVP_VALOFF(nvp));
                /*
                 * Null out pointers that are meaningless in the packed
                 * structure. The addresses may not be aligned, so we have
                 * to use bzero.
                 */
                bzero(strp, NVP_NELEM(nvp) * sizeof (uint64_t));
                break;
        }
        case NVS_OP_DECODE: {
                char **strp = (void *)NVP_VALUE(nvp);
                char *buf = ((char *)strp + NVP_NELEM(nvp) * sizeof (uint64_t));
                int i;

                for (i = 0; i < NVP_NELEM(nvp); i++) {
                        strp[i] = buf;
                        buf += strlen(buf) + 1;
                }
                break;
        }
        }
}

static int
nvs_native_nvp_op(nvstream_t *nvs, nvpair_t *nvp)
{
        data_type_t type;
        int value_sz;
        int ret = 0;

        /*
         * We do the initial bcopy of the data before we look at
         * the nvpair type, because when we're decoding, we won't
         * have the correct values for the pair until we do the bcopy.
         */
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
        case NVS_OP_DECODE:
                if (native_cp(nvs, nvp, nvp->nvp_size) != 0)
                        return (EFAULT);
                break;
        default:
                return (EINVAL);
        }

        /* verify nvp_name_sz, check the name string length */
        if (i_validate_nvpair_name(nvp) != 0)
                return (EFAULT);

        type = NVP_TYPE(nvp);

        /*
         * Verify type and nelem and get the value size.
         * In case of data types DATA_TYPE_STRING and DATA_TYPE_STRING_ARRAY
         * is the size of the string(s) excluded.
         */
        if ((value_sz = i_get_value_size(type, NULL, NVP_NELEM(nvp))) < 0)
                return (EFAULT);

        if (NVP_SIZE_CALC(nvp->nvp_name_sz, value_sz) > nvp->nvp_size)
                return (EFAULT);

        switch (type) {
        case DATA_TYPE_NVLIST:
                ret = nvpair_native_embedded(nvs, nvp);
                break;
        case DATA_TYPE_NVLIST_ARRAY:
                ret = nvpair_native_embedded_array(nvs, nvp);
                break;
        case DATA_TYPE_STRING_ARRAY:
                nvpair_native_string_array(nvs, nvp);
                break;
        default:
                break;
        }

        return (ret);
}

static int
nvs_native_nvp_size(nvstream_t *nvs, nvpair_t *nvp, size_t *size)
{
        uint64_t nvp_sz = nvp->nvp_size;

        switch (NVP_TYPE(nvp)) {
        case DATA_TYPE_NVLIST: {
                size_t nvsize = 0;

                if (nvs_operation(nvs, EMBEDDED_NVL(nvp), &nvsize) != 0)
                        return (EINVAL);

                nvp_sz += nvsize;
                break;
        }
        case DATA_TYPE_NVLIST_ARRAY: {
                size_t nvsize;

                if (nvs_embedded_nvl_array(nvs, nvp, &nvsize) != 0)
                        return (EINVAL);

                nvp_sz += nvsize;
                break;
        }
        default:
                break;
        }

        if (nvp_sz > INT32_MAX)
                return (EINVAL);

        *size = nvp_sz;

        return (0);
}

static int
nvs_native_nvpair(nvstream_t *nvs, nvpair_t *nvp, size_t *size)
{
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
                return (nvs_native_nvp_op(nvs, nvp));

        case NVS_OP_DECODE: {
                nvs_native_t *native = (nvs_native_t *)nvs->nvs_private;
                int32_t decode_len;

                /* try to read the size value from the stream */
                if (native->n_curr + sizeof (int32_t) > native->n_end)
                        return (EFAULT);
                bcopy(native->n_curr, &decode_len, sizeof (int32_t));

                /* sanity check the size value */
                if (decode_len < 0 ||
                    decode_len > native->n_end - native->n_curr)
                        return (EFAULT);

                *size = decode_len;

                /*
                 * If at the end of the stream then move the cursor
                 * forward, otherwise nvpair_native_op() will read
                 * the entire nvpair at the same cursor position.
                 */
                if (*size == 0)
                        native->n_curr += sizeof (int32_t);
                break;
        }

        default:
                return (EINVAL);
        }

        return (0);
}

static const nvs_ops_t nvs_native_ops = {
        .nvs_nvlist = nvs_native_nvlist,
        .nvs_nvpair = nvs_native_nvpair,
        .nvs_nvp_op = nvs_native_nvp_op,
        .nvs_nvp_size = nvs_native_nvp_size,
        .nvs_nvl_fini = nvs_native_nvl_fini
};

static int
nvs_native(nvstream_t *nvs, nvlist_t *nvl, char *buf, size_t *buflen)
{
        nvs_native_t native;
        int err;

        nvs->nvs_ops = &nvs_native_ops;

        if ((err = nvs_native_create(nvs, &native, buf + sizeof (nvs_header_t),
            *buflen - sizeof (nvs_header_t))) != 0)
                return (err);

        err = nvs_operation(nvs, nvl, buflen);

        nvs_native_destroy(nvs);

        return (err);
}

/*
 * XDR encoding functions
 *
 * An xdr packed nvlist is encoded as:
 *
 *  - encoding methode and host endian (4 bytes)
 *  - nvl_version (4 bytes)
 *  - nvl_nvflag (4 bytes)
 *
 *  - encoded nvpairs, the format of one xdr encoded nvpair is:
 *      - encoded size of the nvpair (4 bytes)
 *      - decoded size of the nvpair (4 bytes)
 *      - name string, (4 + sizeof(NV_ALIGN4(string))
 *        a string is coded as size (4 bytes) and data
 *      - data type (4 bytes)
 *      - number of elements in the nvpair (4 bytes)
 *      - data
 *
 *  - 2 zero's for end of the entire list (8 bytes)
 */
static int
nvs_xdr_create(nvstream_t *nvs, XDR *xdr, char *buf, size_t buflen)
{
        /* xdr data must be 4 byte aligned */
        if ((ulong_t)buf % 4 != 0)
                return (EFAULT);

        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
                xdrmem_create(xdr, buf, (uint_t)buflen, XDR_ENCODE);
                nvs->nvs_private = xdr;
                return (0);
        case NVS_OP_DECODE:
                xdrmem_create(xdr, buf, (uint_t)buflen, XDR_DECODE);
                nvs->nvs_private = xdr;
                return (0);
        case NVS_OP_GETSIZE:
                nvs->nvs_private = NULL;
                return (0);
        default:
                return (EINVAL);
        }
}

static void
nvs_xdr_destroy(nvstream_t *nvs)
{
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
        case NVS_OP_DECODE:
                xdr_destroy((XDR *)nvs->nvs_private);
                break;
        default:
                break;
        }
}

static int
nvs_xdr_nvlist(nvstream_t *nvs, nvlist_t *nvl, size_t *size)
{
        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE:
        case NVS_OP_DECODE: {
                XDR     *xdr = nvs->nvs_private;

                if (!xdr_int(xdr, &nvl->nvl_version) ||
                    !xdr_u_int(xdr, &nvl->nvl_nvflag))
                        return (EFAULT);
                break;
        }
        case NVS_OP_GETSIZE: {
                /*
                 * 2 * 4 for nvl_version + nvl_nvflag
                 * and 8 for end of the entire list
                 */
                *size += 2 * 4 + 8;
                break;
        }
        default:
                return (EINVAL);
        }
        return (0);
}

static int
nvs_xdr_nvl_fini(nvstream_t *nvs)
{
        if (nvs->nvs_op == NVS_OP_ENCODE) {
                XDR *xdr = nvs->nvs_private;
                int zero = 0;

                if (!xdr_int(xdr, &zero) || !xdr_int(xdr, &zero))
                        return (EFAULT);
        }

        return (0);
}

/*
 * The format of xdr encoded nvpair is:
 * encode_size, decode_size, name string, data type, nelem, data
 */
static int
nvs_xdr_nvp_op(nvstream_t *nvs, nvpair_t *nvp)
{
        data_type_t type;
        char    *buf;
        char    *buf_end = (char *)nvp + nvp->nvp_size;
        int     value_sz;
        uint_t  nelem, buflen;
        bool_t  ret = FALSE;
        XDR     *xdr = nvs->nvs_private;

        ASSERT(xdr != NULL && nvp != NULL);

        /* name string */
        if ((buf = NVP_NAME(nvp)) >= buf_end)
                return (EFAULT);
        buflen = buf_end - buf;

        if (!xdr_string(xdr, &buf, buflen - 1))
                return (EFAULT);
        nvp->nvp_name_sz = strlen(buf) + 1;

        /* type and nelem */
        if (!xdr_int(xdr, (int *)&nvp->nvp_type) ||
            !xdr_int(xdr, &nvp->nvp_value_elem))
                return (EFAULT);

        type = NVP_TYPE(nvp);
        nelem = nvp->nvp_value_elem;

        /*
         * Verify type and nelem and get the value size.
         * In case of data types DATA_TYPE_STRING and DATA_TYPE_STRING_ARRAY
         * is the size of the string(s) excluded.
         */
        if ((value_sz = i_get_value_size(type, NULL, nelem)) < 0)
                return (EFAULT);

        /* if there is no data to extract then return */
        if (nelem == 0)
                return (0);

        /* value */
        if ((buf = NVP_VALUE(nvp)) >= buf_end)
                return (EFAULT);
        buflen = buf_end - buf;

        if (buflen < value_sz)
                return (EFAULT);

        switch (type) {
        case DATA_TYPE_NVLIST:
                if (nvs_embedded(nvs, (void *)buf) == 0)
                        return (0);
                break;

        case DATA_TYPE_NVLIST_ARRAY:
                if (nvs_embedded_nvl_array(nvs, nvp, NULL) == 0)
                        return (0);
                break;

        case DATA_TYPE_BOOLEAN:
                ret = TRUE;
                break;

        case DATA_TYPE_BYTE:
        case DATA_TYPE_INT8:
        case DATA_TYPE_UINT8:
                ret = xdr_char(xdr, buf);
                break;

        case DATA_TYPE_INT16:
                ret = xdr_short(xdr, (void *)buf);
                break;

        case DATA_TYPE_UINT16:
                ret = xdr_u_short(xdr, (void *)buf);
                break;

        case DATA_TYPE_BOOLEAN_VALUE:
        case DATA_TYPE_INT32:
                ret = xdr_int(xdr, (void *)buf);
                break;

        case DATA_TYPE_UINT32:
                ret = xdr_u_int(xdr, (void *)buf);
                break;

        case DATA_TYPE_INT64:
                ret = xdr_longlong_t(xdr, (void *)buf);
                break;

        case DATA_TYPE_UINT64:
                ret = xdr_u_longlong_t(xdr, (void *)buf);
                break;

        case DATA_TYPE_HRTIME:
                /*
                 * NOTE: must expose the definition of hrtime_t here
                 */
                ret = xdr_longlong_t(xdr, (void *)buf);
                break;
#if !defined(_KERNEL)
        case DATA_TYPE_DOUBLE:
                ret = xdr_double(xdr, (void *)buf);
                break;
#endif
        case DATA_TYPE_STRING:
                ret = xdr_string(xdr, &buf, buflen - 1);
                break;

        case DATA_TYPE_BYTE_ARRAY:
                ret = xdr_opaque(xdr, buf, nelem);
                break;

        case DATA_TYPE_INT8_ARRAY:
        case DATA_TYPE_UINT8_ARRAY:
                ret = xdr_array(xdr, &buf, &nelem, buflen, sizeof (int8_t),
                    (xdrproc_t)xdr_char);
                break;

        case DATA_TYPE_INT16_ARRAY:
                ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (int16_t),
                    sizeof (int16_t), (xdrproc_t)xdr_short);
                break;

        case DATA_TYPE_UINT16_ARRAY:
                ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (uint16_t),
                    sizeof (uint16_t), (xdrproc_t)xdr_u_short);
                break;

        case DATA_TYPE_BOOLEAN_ARRAY:
        case DATA_TYPE_INT32_ARRAY:
                ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (int32_t),
                    sizeof (int32_t), (xdrproc_t)xdr_int);
                break;

        case DATA_TYPE_UINT32_ARRAY:
                ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (uint32_t),
                    sizeof (uint32_t), (xdrproc_t)xdr_u_int);
                break;

        case DATA_TYPE_INT64_ARRAY:
                ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (int64_t),
                    sizeof (int64_t), (xdrproc_t)xdr_longlong_t);
                break;

        case DATA_TYPE_UINT64_ARRAY:
                ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (uint64_t),
                    sizeof (uint64_t), (xdrproc_t)xdr_u_longlong_t);
                break;

        case DATA_TYPE_STRING_ARRAY: {
                size_t len = nelem * sizeof (uint64_t);
                char **strp = (void *)buf;
                int i;

                if (nvs->nvs_op == NVS_OP_DECODE)
                        bzero(buf, len);        /* don't trust packed data */

                for (i = 0; i < nelem; i++) {
                        if (buflen <= len)
                                return (EFAULT);

                        buf += len;
                        buflen -= len;

                        if (xdr_string(xdr, &buf, buflen - 1) != TRUE)
                                return (EFAULT);

                        if (nvs->nvs_op == NVS_OP_DECODE)
                                strp[i] = buf;
                        len = strlen(buf) + 1;
                }
                ret = TRUE;
                break;
        }
        default:
                break;
        }

        return (ret == TRUE ? 0 : EFAULT);
}

static int
nvs_xdr_nvp_size(nvstream_t *nvs, nvpair_t *nvp, size_t *size)
{
        data_type_t type = NVP_TYPE(nvp);
        /*
         * encode_size + decode_size + name string size + data type + nelem
         * where name string size = 4 + NV_ALIGN4(strlen(NVP_NAME(nvp)))
         */
        uint64_t nvp_sz = 4 + 4 + 4 + NV_ALIGN4(strlen(NVP_NAME(nvp))) + 4 + 4;

        switch (type) {
        case DATA_TYPE_BOOLEAN:
                break;

        case DATA_TYPE_BOOLEAN_VALUE:
        case DATA_TYPE_BYTE:
        case DATA_TYPE_INT8:
        case DATA_TYPE_UINT8:
        case DATA_TYPE_INT16:
        case DATA_TYPE_UINT16:
        case DATA_TYPE_INT32:
        case DATA_TYPE_UINT32:
                nvp_sz += 4;    /* 4 is the minimum xdr unit */
                break;

        case DATA_TYPE_INT64:
        case DATA_TYPE_UINT64:
        case DATA_TYPE_HRTIME:
#if !defined(_KERNEL)
        case DATA_TYPE_DOUBLE:
#endif
                nvp_sz += 8;
                break;

        case DATA_TYPE_STRING:
                nvp_sz += 4 + NV_ALIGN4(strlen((char *)NVP_VALUE(nvp)));
                break;

        case DATA_TYPE_BYTE_ARRAY:
                nvp_sz += NV_ALIGN4(NVP_NELEM(nvp));
                break;

        case DATA_TYPE_BOOLEAN_ARRAY:
        case DATA_TYPE_INT8_ARRAY:
        case DATA_TYPE_UINT8_ARRAY:
        case DATA_TYPE_INT16_ARRAY:
        case DATA_TYPE_UINT16_ARRAY:
        case DATA_TYPE_INT32_ARRAY:
        case DATA_TYPE_UINT32_ARRAY:
                nvp_sz += 4 + 4 * (uint64_t)NVP_NELEM(nvp);
                break;

        case DATA_TYPE_INT64_ARRAY:
        case DATA_TYPE_UINT64_ARRAY:
                nvp_sz += 4 + 8 * (uint64_t)NVP_NELEM(nvp);
                break;

        case DATA_TYPE_STRING_ARRAY: {
                int i;
                char **strs = (void *)NVP_VALUE(nvp);

                for (i = 0; i < NVP_NELEM(nvp); i++)
                        nvp_sz += 4 + NV_ALIGN4(strlen(strs[i]));

                break;
        }

        case DATA_TYPE_NVLIST:
        case DATA_TYPE_NVLIST_ARRAY: {
                size_t nvsize = 0;
                int old_nvs_op = nvs->nvs_op;
                int err;

                nvs->nvs_op = NVS_OP_GETSIZE;
                if (type == DATA_TYPE_NVLIST)
                        err = nvs_operation(nvs, EMBEDDED_NVL(nvp), &nvsize);
                else
                        err = nvs_embedded_nvl_array(nvs, nvp, &nvsize);
                nvs->nvs_op = old_nvs_op;

                if (err != 0)
                        return (EINVAL);

                nvp_sz += nvsize;
                break;
        }

        default:
                return (EINVAL);
        }

        if (nvp_sz > INT32_MAX)
                return (EINVAL);

        *size = nvp_sz;

        return (0);
}


/*
 * The NVS_XDR_MAX_LEN macro takes a packed xdr buffer of size x and estimates
 * the largest nvpair that could be encoded in the buffer.
 *
 * See comments above nvpair_xdr_op() for the format of xdr encoding.
 * The size of a xdr packed nvpair without any data is 5 words.
 *
 * Using the size of the data directly as an estimate would be ok
 * in all cases except one.  If the data type is of DATA_TYPE_STRING_ARRAY
 * then the actual nvpair has space for an array of pointers to index
 * the strings.  These pointers are not encoded into the packed xdr buffer.
 *
 * If the data is of type DATA_TYPE_STRING_ARRAY and all the strings are
 * of length 0, then each string is endcoded in xdr format as a single word.
 * Therefore when expanded to an nvpair there will be 2.25 word used for
 * each string.  (a int64_t allocated for pointer usage, and a single char
 * for the null termination.)
 *
 * This is the calculation performed by the NVS_XDR_MAX_LEN macro.
 */
#define NVS_XDR_HDR_LEN         ((size_t)(5 * 4))
#define NVS_XDR_DATA_LEN(y)     (((size_t)(y) <= NVS_XDR_HDR_LEN) ? \
                                        0 : ((size_t)(y) - NVS_XDR_HDR_LEN))
#define NVS_XDR_MAX_LEN(x)      (NVP_SIZE_CALC(1, 0) + \
                                        (NVS_XDR_DATA_LEN(x) * 2) + \
                                        NV_ALIGN4((NVS_XDR_DATA_LEN(x) / 4)))

static int
nvs_xdr_nvpair(nvstream_t *nvs, nvpair_t *nvp, size_t *size)
{
        XDR     *xdr = nvs->nvs_private;
        int32_t encode_len, decode_len;

        switch (nvs->nvs_op) {
        case NVS_OP_ENCODE: {
                size_t nvsize;

                if (nvs_xdr_nvp_size(nvs, nvp, &nvsize) != 0)
                        return (EFAULT);

                decode_len = nvp->nvp_size;
                encode_len = nvsize;
                if (!xdr_int(xdr, &encode_len) || !xdr_int(xdr, &decode_len))
                        return (EFAULT);

                return (nvs_xdr_nvp_op(nvs, nvp));
        }
        case NVS_OP_DECODE: {
                struct xdr_bytesrec bytesrec;

                /* get the encode and decode size */
                if (!xdr_int(xdr, &encode_len) || !xdr_int(xdr, &decode_len))
                        return (EFAULT);
                *size = decode_len;

                /* are we at the end of the stream? */
                if (*size == 0)
                        return (0);

                /* sanity check the size parameter */
                if (!xdr_control(xdr, XDR_GET_BYTES_AVAIL, &bytesrec))
                        return (EFAULT);

                if (*size > NVS_XDR_MAX_LEN(bytesrec.xc_num_avail))
                        return (EFAULT);
                break;
        }

        default:
                return (EINVAL);
        }
        return (0);
}

static const struct nvs_ops nvs_xdr_ops = {
        .nvs_nvlist = nvs_xdr_nvlist,
        .nvs_nvpair = nvs_xdr_nvpair,
        .nvs_nvp_op = nvs_xdr_nvp_op,
        .nvs_nvp_size = nvs_xdr_nvp_size,
        .nvs_nvl_fini = nvs_xdr_nvl_fini
};

static int
nvs_xdr(nvstream_t *nvs, nvlist_t *nvl, char *buf, size_t *buflen)
{
        XDR xdr;
        int err;

        nvs->nvs_ops = &nvs_xdr_ops;

        if ((err = nvs_xdr_create(nvs, &xdr, buf + sizeof (nvs_header_t),
            *buflen - sizeof (nvs_header_t))) != 0)
                return (err);

        err = nvs_operation(nvs, nvl, buflen);

        nvs_xdr_destroy(nvs);

        return (err);
}

#if defined(_KERNEL)
static int __init
nvpair_init(void)
{
        return (0);
}

static void __exit
nvpair_fini(void)
{
}

module_init(nvpair_init);
module_exit(nvpair_fini);

MODULE_DESCRIPTION("Generic name/value pair implementation");
MODULE_AUTHOR(ZFS_META_AUTHOR);
MODULE_LICENSE(ZFS_META_LICENSE);
MODULE_VERSION(ZFS_META_VERSION "-" ZFS_META_RELEASE);

EXPORT_SYMBOL(nv_alloc_init);
EXPORT_SYMBOL(nv_alloc_reset);
EXPORT_SYMBOL(nv_alloc_fini);

/* list management */
EXPORT_SYMBOL(nvlist_alloc);
EXPORT_SYMBOL(nvlist_free);
EXPORT_SYMBOL(nvlist_size);
EXPORT_SYMBOL(nvlist_pack);
EXPORT_SYMBOL(nvlist_unpack);
EXPORT_SYMBOL(nvlist_dup);
EXPORT_SYMBOL(nvlist_merge);

EXPORT_SYMBOL(nvlist_xalloc);
EXPORT_SYMBOL(nvlist_xpack);
EXPORT_SYMBOL(nvlist_xunpack);
EXPORT_SYMBOL(nvlist_xdup);
EXPORT_SYMBOL(nvlist_lookup_nv_alloc);

EXPORT_SYMBOL(nvlist_add_nvpair);
EXPORT_SYMBOL(nvlist_add_boolean);
EXPORT_SYMBOL(nvlist_add_boolean_value);
EXPORT_SYMBOL(nvlist_add_byte);
EXPORT_SYMBOL(nvlist_add_int8);
EXPORT_SYMBOL(nvlist_add_uint8);
EXPORT_SYMBOL(nvlist_add_int16);
EXPORT_SYMBOL(nvlist_add_uint16);
EXPORT_SYMBOL(nvlist_add_int32);
EXPORT_SYMBOL(nvlist_add_uint32);
EXPORT_SYMBOL(nvlist_add_int64);
EXPORT_SYMBOL(nvlist_add_uint64);
EXPORT_SYMBOL(nvlist_add_string);
EXPORT_SYMBOL(nvlist_add_nvlist);
EXPORT_SYMBOL(nvlist_add_boolean_array);
EXPORT_SYMBOL(nvlist_add_byte_array);
EXPORT_SYMBOL(nvlist_add_int8_array);
EXPORT_SYMBOL(nvlist_add_uint8_array);
EXPORT_SYMBOL(nvlist_add_int16_array);
EXPORT_SYMBOL(nvlist_add_uint16_array);
EXPORT_SYMBOL(nvlist_add_int32_array);
EXPORT_SYMBOL(nvlist_add_uint32_array);
EXPORT_SYMBOL(nvlist_add_int64_array);
EXPORT_SYMBOL(nvlist_add_uint64_array);
EXPORT_SYMBOL(nvlist_add_string_array);
EXPORT_SYMBOL(nvlist_add_nvlist_array);
EXPORT_SYMBOL(nvlist_next_nvpair);
EXPORT_SYMBOL(nvlist_prev_nvpair);
EXPORT_SYMBOL(nvlist_empty);
EXPORT_SYMBOL(nvlist_add_hrtime);

EXPORT_SYMBOL(nvlist_remove);
EXPORT_SYMBOL(nvlist_remove_nvpair);
EXPORT_SYMBOL(nvlist_remove_all);

EXPORT_SYMBOL(nvlist_lookup_boolean);
EXPORT_SYMBOL(nvlist_lookup_boolean_value);
EXPORT_SYMBOL(nvlist_lookup_byte);
EXPORT_SYMBOL(nvlist_lookup_int8);
EXPORT_SYMBOL(nvlist_lookup_uint8);
EXPORT_SYMBOL(nvlist_lookup_int16);
EXPORT_SYMBOL(nvlist_lookup_uint16);
EXPORT_SYMBOL(nvlist_lookup_int32);
EXPORT_SYMBOL(nvlist_lookup_uint32);
EXPORT_SYMBOL(nvlist_lookup_int64);
EXPORT_SYMBOL(nvlist_lookup_uint64);
EXPORT_SYMBOL(nvlist_lookup_string);
EXPORT_SYMBOL(nvlist_lookup_nvlist);
EXPORT_SYMBOL(nvlist_lookup_boolean_array);
EXPORT_SYMBOL(nvlist_lookup_byte_array);
EXPORT_SYMBOL(nvlist_lookup_int8_array);
EXPORT_SYMBOL(nvlist_lookup_uint8_array);
EXPORT_SYMBOL(nvlist_lookup_int16_array);
EXPORT_SYMBOL(nvlist_lookup_uint16_array);
EXPORT_SYMBOL(nvlist_lookup_int32_array);
EXPORT_SYMBOL(nvlist_lookup_uint32_array);
EXPORT_SYMBOL(nvlist_lookup_int64_array);
EXPORT_SYMBOL(nvlist_lookup_uint64_array);
EXPORT_SYMBOL(nvlist_lookup_string_array);
EXPORT_SYMBOL(nvlist_lookup_nvlist_array);
EXPORT_SYMBOL(nvlist_lookup_hrtime);
EXPORT_SYMBOL(nvlist_lookup_pairs);

EXPORT_SYMBOL(nvlist_lookup_nvpair);
EXPORT_SYMBOL(nvlist_exists);

/* processing nvpair */
EXPORT_SYMBOL(nvpair_name);
EXPORT_SYMBOL(nvpair_type);
EXPORT_SYMBOL(nvpair_value_boolean_value);
EXPORT_SYMBOL(nvpair_value_byte);
EXPORT_SYMBOL(nvpair_value_int8);
EXPORT_SYMBOL(nvpair_value_uint8);
EXPORT_SYMBOL(nvpair_value_int16);
EXPORT_SYMBOL(nvpair_value_uint16);
EXPORT_SYMBOL(nvpair_value_int32);
EXPORT_SYMBOL(nvpair_value_uint32);
EXPORT_SYMBOL(nvpair_value_int64);
EXPORT_SYMBOL(nvpair_value_uint64);
EXPORT_SYMBOL(nvpair_value_string);
EXPORT_SYMBOL(nvpair_value_nvlist);
EXPORT_SYMBOL(nvpair_value_boolean_array);
EXPORT_SYMBOL(nvpair_value_byte_array);
EXPORT_SYMBOL(nvpair_value_int8_array);
EXPORT_SYMBOL(nvpair_value_uint8_array);
EXPORT_SYMBOL(nvpair_value_int16_array);
EXPORT_SYMBOL(nvpair_value_uint16_array);
EXPORT_SYMBOL(nvpair_value_int32_array);
EXPORT_SYMBOL(nvpair_value_uint32_array);
EXPORT_SYMBOL(nvpair_value_int64_array);
EXPORT_SYMBOL(nvpair_value_uint64_array);
EXPORT_SYMBOL(nvpair_value_string_array);
EXPORT_SYMBOL(nvpair_value_nvlist_array);
EXPORT_SYMBOL(nvpair_value_hrtime);

#endif