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