lib/libzfs/libzfs_iter.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
  25  * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
  26  * Copyright (c) 2018 Datto Inc.
  27  */
  28
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <strings.h>
  32 #include <unistd.h>
  33 #include <stddef.h>
  34 #include <libintl.h>
  35 #include <libzfs.h>
  36 #include <libzutil.h>
  37 #include <sys/mntent.h>
  38
  39 #include "libzfs_impl.h"
  40
  41 int
  42 zfs_iter_clones(zfs_handle_t *zhp, zfs_iter_f func, void *data)
  43 {
  44         nvlist_t *nvl = zfs_get_clones_nvl(zhp);
  45         nvpair_t *pair;
  46
  47         if (nvl == NULL)
  48                 return (0);
  49
  50         for (pair = nvlist_next_nvpair(nvl, NULL); pair != NULL;
  51             pair = nvlist_next_nvpair(nvl, pair)) {
  52                 zfs_handle_t *clone = zfs_open(zhp->zfs_hdl, nvpair_name(pair),
  53                     ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME);
  54                 if (clone != NULL) {
  55                         int err = func(clone, data);
  56                         if (err != 0)
  57                                 return (err);
  58                 }
  59         }
  60         return (0);
  61 }
  62
  63 static int
  64 zfs_do_list_ioctl(zfs_handle_t *zhp, int arg, zfs_cmd_t *zc)
  65 {
  66         int rc;
  67         uint64_t        orig_cookie;
  68
  69         orig_cookie = zc->zc_cookie;
  70 top:
  71         (void) strlcpy(zc->zc_name, zhp->zfs_name, sizeof (zc->zc_name));
  72         rc = ioctl(zhp->zfs_hdl->libzfs_fd, arg, zc);
  73
  74         if (rc == -1) {
  75                 switch (errno) {
  76                 case ENOMEM:
  77                         /* expand nvlist memory and try again */
  78                         if (zcmd_expand_dst_nvlist(zhp->zfs_hdl, zc) != 0) {
  79                                 zcmd_free_nvlists(zc);
  80                                 return (-1);
  81                         }
  82                         zc->zc_cookie = orig_cookie;
  83                         goto top;
  84                 /*
  85                  * An errno value of ESRCH indicates normal completion.
  86                  * If ENOENT is returned, then the underlying dataset
  87                  * has been removed since we obtained the handle.
  88                  */
  89                 case ESRCH:
  90                 case ENOENT:
  91                         rc = 1;
  92                         break;
  93                 default:
  94                         rc = zfs_standard_error(zhp->zfs_hdl, errno,
  95                             dgettext(TEXT_DOMAIN,
  96                             "cannot iterate filesystems"));
  97                         break;
  98                 }
  99         }
 100         return (rc);
 101 }
 102
 103 /*
 104  * Iterate over all child filesystems
 105  */
 106 int
 107 zfs_iter_filesystems(zfs_handle_t *zhp, zfs_iter_f func, void *data)
 108 {
 109         zfs_cmd_t zc = {"\0"};
 110         zfs_handle_t *nzhp;
 111         int ret;
 112
 113         if (zhp->zfs_type != ZFS_TYPE_FILESYSTEM)
 114                 return (0);
 115
 116         if (zcmd_alloc_dst_nvlist(zhp->zfs_hdl, &zc, 0) != 0)
 117                 return (-1);
 118
 119         while ((ret = zfs_do_list_ioctl(zhp, ZFS_IOC_DATASET_LIST_NEXT,
 120             &zc)) == 0) {
 121                 /*
 122                  * Silently ignore errors, as the only plausible explanation is
 123                  * that the pool has since been removed.
 124                  */
 125                 if ((nzhp = make_dataset_handle_zc(zhp->zfs_hdl,
 126                     &zc)) == NULL) {
 127                         continue;
 128                 }
 129
 130                 if ((ret = func(nzhp, data)) != 0) {
 131                         zcmd_free_nvlists(&zc);
 132                         return (ret);
 133                 }
 134         }
 135         zcmd_free_nvlists(&zc);
 136         return ((ret < 0) ? ret : 0);
 137 }
 138
 139 /*
 140  * Iterate over all snapshots
 141  */
 142 int
 143 zfs_iter_snapshots(zfs_handle_t *zhp, boolean_t simple, zfs_iter_f func,
 144     void *data)
 145 {
 146         zfs_cmd_t zc = {"\0"};
 147         zfs_handle_t *nzhp;
 148         int ret;
 149
 150         if (zhp->zfs_type == ZFS_TYPE_SNAPSHOT ||
 151             zhp->zfs_type == ZFS_TYPE_BOOKMARK)
 152                 return (0);
 153
 154         zc.zc_simple = simple;
 155
 156         if (zcmd_alloc_dst_nvlist(zhp->zfs_hdl, &zc, 0) != 0)
 157                 return (-1);
 158         while ((ret = zfs_do_list_ioctl(zhp, ZFS_IOC_SNAPSHOT_LIST_NEXT,
 159             &zc)) == 0) {
 160
 161                 if (simple)
 162                         nzhp = make_dataset_simple_handle_zc(zhp, &zc);
 163                 else
 164                         nzhp = make_dataset_handle_zc(zhp->zfs_hdl, &zc);
 165                 if (nzhp == NULL)
 166                         continue;
 167
 168                 if ((ret = func(nzhp, data)) != 0) {
 169                         zcmd_free_nvlists(&zc);
 170                         return (ret);
 171                 }
 172         }
 173         zcmd_free_nvlists(&zc);
 174         return ((ret < 0) ? ret : 0);
 175 }
 176
 177 /*
 178  * Iterate over all bookmarks
 179  */
 180 int
 181 zfs_iter_bookmarks(zfs_handle_t *zhp, zfs_iter_f func, void *data)
 182 {
 183         zfs_handle_t *nzhp;
 184         nvlist_t *props = NULL;
 185         nvlist_t *bmarks = NULL;
 186         int err;
 187         nvpair_t *pair;
 188
 189         if ((zfs_get_type(zhp) & (ZFS_TYPE_SNAPSHOT | ZFS_TYPE_BOOKMARK)) != 0)
 190                 return (0);
 191
 192         /* Setup the requested properties nvlist. */
 193         props = fnvlist_alloc();
 194         fnvlist_add_boolean(props, zfs_prop_to_name(ZFS_PROP_GUID));
 195         fnvlist_add_boolean(props, zfs_prop_to_name(ZFS_PROP_CREATETXG));
 196         fnvlist_add_boolean(props, zfs_prop_to_name(ZFS_PROP_CREATION));
 197
 198         if ((err = lzc_get_bookmarks(zhp->zfs_name, props, &bmarks)) != 0)
 199                 goto out;
 200
 201         for (pair = nvlist_next_nvpair(bmarks, NULL);
 202             pair != NULL; pair = nvlist_next_nvpair(bmarks, pair)) {
 203                 char name[ZFS_MAX_DATASET_NAME_LEN];
 204                 char *bmark_name;
 205                 nvlist_t *bmark_props;
 206
 207                 bmark_name = nvpair_name(pair);
 208                 bmark_props = fnvpair_value_nvlist(pair);
 209
 210                 if (snprintf(name, sizeof (name), "%s#%s", zhp->zfs_name,
 211                     bmark_name) >= sizeof (name)) {
 212                         err = EINVAL;
 213                         goto out;
 214                 }
 215
 216                 nzhp = make_bookmark_handle(zhp, name, bmark_props);
 217                 if (nzhp == NULL)
 218                         continue;
 219
 220                 if ((err = func(nzhp, data)) != 0)
 221                         goto out;
 222         }
 223
 224 out:
 225         fnvlist_free(props);
 226         fnvlist_free(bmarks);
 227
 228         return (err);
 229 }
 230
 231 /*
 232  * Routines for dealing with the sorted snapshot functionality
 233  */
 234 typedef struct zfs_node {
 235         zfs_handle_t    *zn_handle;
 236         avl_node_t      zn_avlnode;
 237 } zfs_node_t;
 238
 239 static int
 240 zfs_sort_snaps(zfs_handle_t *zhp, void *data)
 241 {
 242         avl_tree_t *avl = data;
 243         zfs_node_t *node;
 244         zfs_node_t search;
 245
 246         search.zn_handle = zhp;
 247         node = avl_find(avl, &search, NULL);
 248         if (node) {
 249                 /*
 250                  * If this snapshot was renamed while we were creating the
 251                  * AVL tree, it's possible that we already inserted it under
 252                  * its old name. Remove the old handle before adding the new
 253                  * one.
 254                  */
 255                 zfs_close(node->zn_handle);
 256                 avl_remove(avl, node);
 257                 free(node);
 258         }
 259
 260         node = zfs_alloc(zhp->zfs_hdl, sizeof (zfs_node_t));
 261         node->zn_handle = zhp;
 262         avl_add(avl, node);
 263
 264         return (0);
 265 }
 266
 267 static int
 268 zfs_snapshot_compare(const void *larg, const void *rarg)
 269 {
 270         zfs_handle_t *l = ((zfs_node_t *)larg)->zn_handle;
 271         zfs_handle_t *r = ((zfs_node_t *)rarg)->zn_handle;
 272         uint64_t lcreate, rcreate;
 273
 274         /*
 275          * Sort them according to creation time.  We use the hidden
 276          * CREATETXG property to get an absolute ordering of snapshots.
 277          */
 278         lcreate = zfs_prop_get_int(l, ZFS_PROP_CREATETXG);
 279         rcreate = zfs_prop_get_int(r, ZFS_PROP_CREATETXG);
 280
 281         return (AVL_CMP(lcreate, rcreate));
 282 }
 283
 284 int
 285 zfs_iter_snapshots_sorted(zfs_handle_t *zhp, zfs_iter_f callback, void *data)
 286 {
 287         int ret = 0;
 288         zfs_node_t *node;
 289         avl_tree_t avl;
 290         void *cookie = NULL;
 291
 292         avl_create(&avl, zfs_snapshot_compare,
 293             sizeof (zfs_node_t), offsetof(zfs_node_t, zn_avlnode));
 294
 295         ret = zfs_iter_snapshots(zhp, B_FALSE, zfs_sort_snaps, &avl);
 296
 297         for (node = avl_first(&avl); node != NULL; node = AVL_NEXT(&avl, node))
 298                 ret |= callback(node->zn_handle, data);
 299
 300         while ((node = avl_destroy_nodes(&avl, &cookie)) != NULL)
 301                 free(node);
 302
 303         avl_destroy(&avl);
 304
 305         return (ret);
 306 }
 307
 308 typedef struct {
 309         char *ssa_first;
 310         char *ssa_last;
 311         boolean_t ssa_seenfirst;
 312         boolean_t ssa_seenlast;
 313         zfs_iter_f ssa_func;
 314         void *ssa_arg;
 315 } snapspec_arg_t;
 316
 317 static int
 318 snapspec_cb(zfs_handle_t *zhp, void *arg)
 319 {
 320         snapspec_arg_t *ssa = arg;
 321         const char *shortsnapname;
 322         int err = 0;
 323
 324         if (ssa->ssa_seenlast)
 325                 return (0);
 326
 327         shortsnapname = strchr(zfs_get_name(zhp), '@') + 1;
 328         if (!ssa->ssa_seenfirst && strcmp(shortsnapname, ssa->ssa_first) == 0)
 329                 ssa->ssa_seenfirst = B_TRUE;
 330         if (strcmp(shortsnapname, ssa->ssa_last) == 0)
 331                 ssa->ssa_seenlast = B_TRUE;
 332
 333         if (ssa->ssa_seenfirst) {
 334                 err = ssa->ssa_func(zhp, ssa->ssa_arg);
 335         } else {
 336                 zfs_close(zhp);
 337         }
 338
 339         return (err);
 340 }
 341
 342 /*
 343  * spec is a string like "A,B%C,D"
 344  *
 345  * <snaps>, where <snaps> can be:
 346  *      <snap>          (single snapshot)
 347  *      <snap>%<snap>   (range of snapshots, inclusive)
 348  *      %<snap>         (range of snapshots, starting with earliest)
 349  *      <snap>%         (range of snapshots, ending with last)
 350  *      %               (all snapshots)
 351  *      <snaps>[,...]   (comma separated list of the above)
 352  *
 353  * If a snapshot can not be opened, continue trying to open the others, but
 354  * return ENOENT at the end.
 355  */
 356 int
 357 zfs_iter_snapspec(zfs_handle_t *fs_zhp, const char *spec_orig,
 358     zfs_iter_f func, void *arg)
 359 {
 360         char *buf, *comma_separated, *cp;
 361         int err = 0;
 362         int ret = 0;
 363
 364         buf = zfs_strdup(fs_zhp->zfs_hdl, spec_orig);
 365         cp = buf;
 366
 367         while ((comma_separated = strsep(&cp, ",")) != NULL) {
 368                 char *pct = strchr(comma_separated, '%');
 369                 if (pct != NULL) {
 370                         snapspec_arg_t ssa = { 0 };
 371                         ssa.ssa_func = func;
 372                         ssa.ssa_arg = arg;
 373
 374                         if (pct == comma_separated)
 375                                 ssa.ssa_seenfirst = B_TRUE;
 376                         else
 377                                 ssa.ssa_first = comma_separated;
 378                         *pct = '\0';
 379                         ssa.ssa_last = pct + 1;
 380
 381                         /*
 382                          * If there is a lastname specified, make sure it
 383                          * exists.
 384                          */
 385                         if (ssa.ssa_last[0] != '\0') {
 386                                 char snapname[ZFS_MAX_DATASET_NAME_LEN];
 387                                 (void) snprintf(snapname, sizeof (snapname),
 388                                     "%s@%s", zfs_get_name(fs_zhp),
 389                                     ssa.ssa_last);
 390                                 if (!zfs_dataset_exists(fs_zhp->zfs_hdl,
 391                                     snapname, ZFS_TYPE_SNAPSHOT)) {
 392                                         ret = ENOENT;
 393                                         continue;
 394                                 }
 395                         }
 396
 397                         err = zfs_iter_snapshots_sorted(fs_zhp,
 398                             snapspec_cb, &ssa);
 399                         if (ret == 0)
 400                                 ret = err;
 401                         if (ret == 0 && (!ssa.ssa_seenfirst ||
 402                             (ssa.ssa_last[0] != '\0' && !ssa.ssa_seenlast))) {
 403                                 ret = ENOENT;
 404                         }
 405                 } else {
 406                         char snapname[ZFS_MAX_DATASET_NAME_LEN];
 407                         zfs_handle_t *snap_zhp;
 408                         (void) snprintf(snapname, sizeof (snapname), "%s@%s",
 409                             zfs_get_name(fs_zhp), comma_separated);
 410                         snap_zhp = make_dataset_handle(fs_zhp->zfs_hdl,
 411                             snapname);
 412                         if (snap_zhp == NULL) {
 413                                 ret = ENOENT;
 414                                 continue;
 415                         }
 416                         err = func(snap_zhp, arg);
 417                         if (ret == 0)
 418                                 ret = err;
 419                 }
 420         }
 421
 422         free(buf);
 423         return (ret);
 424 }
 425
 426 /*
 427  * Iterate over all children, snapshots and filesystems
 428  * Process snapshots before filesystems because they are nearer the input
 429  * handle: this is extremely important when used with zfs_iter_f functions
 430  * looking for data, following the logic that we would like to find it as soon
 431  * and as close as possible.
 432  */
 433 int
 434 zfs_iter_children(zfs_handle_t *zhp, zfs_iter_f func, void *data)
 435 {
 436         int ret;
 437
 438         if ((ret = zfs_iter_snapshots(zhp, B_FALSE, func, data)) != 0)
 439                 return (ret);
 440
 441         return (zfs_iter_filesystems(zhp, func, data));
 442 }
 443
 444
 445 typedef struct iter_stack_frame {
 446         struct iter_stack_frame *next;
 447         zfs_handle_t *zhp;
 448 } iter_stack_frame_t;
 449
 450 typedef struct iter_dependents_arg {
 451         boolean_t first;
 452         boolean_t allowrecursion;
 453         iter_stack_frame_t *stack;
 454         zfs_iter_f func;
 455         void *data;
 456 } iter_dependents_arg_t;
 457
 458 static int
 459 iter_dependents_cb(zfs_handle_t *zhp, void *arg)
 460 {
 461         iter_dependents_arg_t *ida = arg;
 462         int err = 0;
 463         boolean_t first = ida->first;
 464         ida->first = B_FALSE;
 465
 466         if (zhp->zfs_type == ZFS_TYPE_SNAPSHOT) {
 467                 err = zfs_iter_clones(zhp, iter_dependents_cb, ida);
 468         } else if (zhp->zfs_type != ZFS_TYPE_BOOKMARK) {
 469                 iter_stack_frame_t isf;
 470                 iter_stack_frame_t *f;
 471
 472                 /*
 473                  * check if there is a cycle by seeing if this fs is already
 474                  * on the stack.
 475                  */
 476                 for (f = ida->stack; f != NULL; f = f->next) {
 477                         if (f->zhp->zfs_dmustats.dds_guid ==
 478                             zhp->zfs_dmustats.dds_guid) {
 479                                 if (ida->allowrecursion) {
 480                                         zfs_close(zhp);
 481                                         return (0);
 482                                 } else {
 483                                         zfs_error_aux(zhp->zfs_hdl,
 484                                             dgettext(TEXT_DOMAIN,
 485                                             "recursive dependency at '%s'"),
 486                                             zfs_get_name(zhp));
 487                                         err = zfs_error(zhp->zfs_hdl,
 488                                             EZFS_RECURSIVE,
 489                                             dgettext(TEXT_DOMAIN,
 490                                             "cannot determine dependent "
 491                                             "datasets"));
 492                                         zfs_close(zhp);
 493                                         return (err);
 494                                 }
 495                         }
 496                 }
 497
 498                 isf.zhp = zhp;
 499                 isf.next = ida->stack;
 500                 ida->stack = &isf;
 501                 err = zfs_iter_filesystems(zhp, iter_dependents_cb, ida);
 502                 if (err == 0)
 503                         err = zfs_iter_snapshots(zhp, B_FALSE,
 504                             iter_dependents_cb, ida);
 505                 ida->stack = isf.next;
 506         }
 507
 508         if (!first && err == 0)
 509                 err = ida->func(zhp, ida->data);
 510         else
 511                 zfs_close(zhp);
 512
 513         return (err);
 514 }
 515
 516 int
 517 zfs_iter_dependents(zfs_handle_t *zhp, boolean_t allowrecursion,
 518     zfs_iter_f func, void *data)
 519 {
 520         iter_dependents_arg_t ida;
 521         ida.allowrecursion = allowrecursion;
 522         ida.stack = NULL;
 523         ida.func = func;
 524         ida.data = data;
 525         ida.first = B_TRUE;
 526         return (iter_dependents_cb(zfs_handle_dup(zhp), &ida));
 527 }
 528
 529 /*
 530  * Iterate over mounted children of the specified dataset
 531  */
 532 int
 533 zfs_iter_mounted(zfs_handle_t *zhp, zfs_iter_f func, void *data)
 534 {
 535         char mnt_prop[ZFS_MAXPROPLEN];
 536         struct mnttab entry;
 537         zfs_handle_t *mtab_zhp;
 538         size_t namelen = strlen(zhp->zfs_name);
 539         FILE *mnttab;
 540         int err = 0;
 541
 542         if ((mnttab = fopen(MNTTAB, "r")) == NULL)
 543                 return (ENOENT);
 544
 545         while (err == 0 && getmntent(mnttab, &entry) == 0) {
 546                 /* Ignore non-ZFS entries */
 547                 if (strcmp(entry.mnt_fstype, MNTTYPE_ZFS) != 0)
 548                         continue;
 549
 550                 /* Ignore datasets not within the provided dataset */
 551                 if (strncmp(entry.mnt_special, zhp->zfs_name, namelen) != 0 ||
 552                     (entry.mnt_special[namelen] != '/' &&
 553                     entry.mnt_special[namelen] != '@'))
 554                         continue;
 555
 556                 if ((mtab_zhp = zfs_open(zhp->zfs_hdl, entry.mnt_special,
 557                     ZFS_TYPE_FILESYSTEM)) == NULL)
 558                         continue;
 559
 560                 /* Ignore legacy mounts as they are user managed */
 561                 verify(zfs_prop_get(mtab_zhp, ZFS_PROP_MOUNTPOINT, mnt_prop,
 562                     sizeof (mnt_prop), NULL, NULL, 0, B_FALSE) == 0);
 563                 if (strcmp(mnt_prop, "legacy") == 0) {
 564                         zfs_close(mtab_zhp);
 565                         continue;
 566                 }
 567
 568                 err = func(mtab_zhp, data);
 569         }
 570
 571         fclose(mnttab);
 572
 573         return (err);
 574 }