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) 2013 by Delphix. All rights reserved. 24 * Copyright (c) 2013 Steven Hartland. All rights reserved. 25 */ 26 27 /* 28 * LibZFS_Core (lzc) is intended to replace most functionality in libzfs. 29 * It has the following characteristics: 30 * 31 * - Thread Safe. libzfs_core is accessible concurrently from multiple 32 * threads. This is accomplished primarily by avoiding global data 33 * (e.g. caching). Since it's thread-safe, there is no reason for a 34 * process to have multiple libzfs "instances". Therefore, we store 35 * our few pieces of data (e.g. the file descriptor) in global 36 * variables. The fd is reference-counted so that the libzfs_core 37 * library can be "initialized" multiple times (e.g. by different 38 * consumers within the same process). 39 * 40 * - Committed Interface. The libzfs_core interface will be committed, 41 * therefore consumers can compile against it and be confident that 42 * their code will continue to work on future releases of this code. 43 * Currently, the interface is Evolving (not Committed), but we intend 44 * to commit to it once it is more complete and we determine that it 45 * meets the needs of all consumers. 46 * 47 * - Programatic Error Handling. libzfs_core communicates errors with 48 * defined error numbers, and doesn't print anything to stdout/stderr. 49 * 50 * - Thin Layer. libzfs_core is a thin layer, marshaling arguments 51 * to/from the kernel ioctls. There is generally a 1:1 correspondence 52 * between libzfs_core functions and ioctls to /dev/zfs. 53 * 54 * - Clear Atomicity. Because libzfs_core functions are generally 1:1 55 * with kernel ioctls, and kernel ioctls are general atomic, each 56 * libzfs_core function is atomic. For example, creating multiple 57 * snapshots with a single call to lzc_snapshot() is atomic -- it 58 * can't fail with only some of the requested snapshots created, even 59 * in the event of power loss or system crash. 60 * 61 * - Continued libzfs Support. Some higher-level operations (e.g. 62 * support for "zfs send -R") are too complicated to fit the scope of 63 * libzfs_core. This functionality will continue to live in libzfs. 64 * Where appropriate, libzfs will use the underlying atomic operations 65 * of libzfs_core. For example, libzfs may implement "zfs send -R | 66 * zfs receive" by using individual "send one snapshot", rename, 67 * destroy, and "receive one snapshot" operations in libzfs_core. 68 * /sbin/zfs and /zbin/zpool will link with both libzfs and 69 * libzfs_core. Other consumers should aim to use only libzfs_core, 70 * since that will be the supported, stable interface going forwards. 71 */ 72 73 #include <libzfs_core.h> 74 #include <ctype.h> 75 #include <unistd.h> 76 #include <stdlib.h> 77 #include <string.h> 78 #include <errno.h> 79 #include <fcntl.h> 80 #include <pthread.h> 81 #include <sys/nvpair.h> 82 #include <sys/param.h> 83 #include <sys/types.h> 84 #include <sys/stat.h> 85 #include <sys/zfs_ioctl.h> 86 87 static int g_fd; 88 static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER; 89 static int g_refcount; 90 91 int 92 libzfs_core_init(void) 93 { 94 (void) pthread_mutex_lock(&g_lock); 95 if (g_refcount == 0) { 96 g_fd = open("/dev/zfs", O_RDWR); 97 if (g_fd < 0) { 98 (void) pthread_mutex_unlock(&g_lock); 99 return (errno); 100 } 101 } 102 g_refcount++; 103 (void) pthread_mutex_unlock(&g_lock); 104 return (0); 105 } 106 107 void 108 libzfs_core_fini(void) 109 { 110 (void) pthread_mutex_lock(&g_lock); 111 ASSERT3S(g_refcount, >, 0); 112 g_refcount--; 113 if (g_refcount == 0) 114 (void) close(g_fd); 115 (void) pthread_mutex_unlock(&g_lock); 116 } 117 118 static int 119 lzc_ioctl(zfs_ioc_t ioc, const char *name, 120 nvlist_t *source, nvlist_t **resultp) 121 { 122 zfs_cmd_t zc = { 0 }; 123 int error = 0; 124 char *packed; 125 size_t size; 126 127 ASSERT3S(g_refcount, >, 0); 128 129 (void) strlcpy(zc.zc_name, name, sizeof (zc.zc_name)); 130 131 packed = fnvlist_pack(source, &size); 132 zc.zc_nvlist_src = (uint64_t)(uintptr_t)packed; 133 zc.zc_nvlist_src_size = size; 134 135 if (resultp != NULL) { 136 *resultp = NULL; 137 zc.zc_nvlist_dst_size = MAX(size * 2, 128 * 1024); 138 zc.zc_nvlist_dst = (uint64_t)(uintptr_t) 139 malloc(zc.zc_nvlist_dst_size); 140 if (zc.zc_nvlist_dst == NULL) { 141 error = ENOMEM; 142 goto out; 143 } 144 } 145 146 while (ioctl(g_fd, ioc, &zc) != 0) { 147 if (errno == ENOMEM && resultp != NULL) { 148 free((void *)(uintptr_t)zc.zc_nvlist_dst); 149 zc.zc_nvlist_dst_size *= 2; 150 zc.zc_nvlist_dst = (uint64_t)(uintptr_t) 151 malloc(zc.zc_nvlist_dst_size); 152 if (zc.zc_nvlist_dst == NULL) { 153 error = ENOMEM; 154 goto out; 155 } 156 } else { 157 error = errno; 158 break; 159 } 160 } 161 if (zc.zc_nvlist_dst_filled) { 162 *resultp = fnvlist_unpack((void *)(uintptr_t)zc.zc_nvlist_dst, 163 zc.zc_nvlist_dst_size); 164 } 165 166 out: 167 fnvlist_pack_free(packed, size); 168 free((void *)(uintptr_t)zc.zc_nvlist_dst); 169 return (error); 170 } 171 172 int 173 lzc_create(const char *fsname, dmu_objset_type_t type, nvlist_t *props) 174 { 175 int error; 176 nvlist_t *args = fnvlist_alloc(); 177 fnvlist_add_int32(args, "type", type); 178 if (props != NULL) 179 fnvlist_add_nvlist(args, "props", props); 180 error = lzc_ioctl(ZFS_IOC_CREATE, fsname, args, NULL); 181 nvlist_free(args); 182 return (error); 183 } 184 185 int 186 lzc_clone(const char *fsname, const char *origin, 187 nvlist_t *props) 188 { 189 int error; 190 nvlist_t *args = fnvlist_alloc(); 191 fnvlist_add_string(args, "origin", origin); 192 if (props != NULL) 193 fnvlist_add_nvlist(args, "props", props); 194 error = lzc_ioctl(ZFS_IOC_CLONE, fsname, args, NULL); 195 nvlist_free(args); 196 return (error); 197 } 198 199 /* 200 * Creates snapshots. 201 * 202 * The keys in the snaps nvlist are the snapshots to be created. 203 * They must all be in the same pool. 204 * 205 * The props nvlist is properties to set. Currently only user properties 206 * are supported. { user:prop_name -> string value } 207 * 208 * The returned results nvlist will have an entry for each snapshot that failed. 209 * The value will be the (int32) error code. 210 * 211 * The return value will be 0 if all snapshots were created, otherwise it will 212 * be the errno of a (unspecified) snapshot that failed. 213 */ 214 int 215 lzc_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t **errlist) 216 { 217 nvpair_t *elem; 218 nvlist_t *args; 219 int error; 220 char pool[MAXNAMELEN]; 221 222 *errlist = NULL; 223 224 /* determine the pool name */ 225 elem = nvlist_next_nvpair(snaps, NULL); 226 if (elem == NULL) 227 return (0); 228 (void) strlcpy(pool, nvpair_name(elem), sizeof (pool)); 229 pool[strcspn(pool, "/@")] = '\0'; 230 231 args = fnvlist_alloc(); 232 fnvlist_add_nvlist(args, "snaps", snaps); 233 if (props != NULL) 234 fnvlist_add_nvlist(args, "props", props); 235 236 error = lzc_ioctl(ZFS_IOC_SNAPSHOT, pool, args, errlist); 237 nvlist_free(args); 238 239 return (error); 240 } 241 242 /* 243 * Destroys snapshots. 244 * 245 * The keys in the snaps nvlist are the snapshots to be destroyed. 246 * They must all be in the same pool. 247 * 248 * Snapshots that do not exist will be silently ignored. 249 * 250 * If 'defer' is not set, and a snapshot has user holds or clones, the 251 * destroy operation will fail and none of the snapshots will be 252 * destroyed. 253 * 254 * If 'defer' is set, and a snapshot has user holds or clones, it will be 255 * marked for deferred destruction, and will be destroyed when the last hold 256 * or clone is removed/destroyed. 257 * 258 * The return value will be 0 if all snapshots were destroyed (or marked for 259 * later destruction if 'defer' is set) or didn't exist to begin with. 260 * 261 * Otherwise the return value will be the errno of a (unspecified) snapshot 262 * that failed, no snapshots will be destroyed, and the errlist will have an 263 * entry for each snapshot that failed. The value in the errlist will be 264 * the (int32) error code. 265 */ 266 int 267 lzc_destroy_snaps(nvlist_t *snaps, boolean_t defer, nvlist_t **errlist) 268 { 269 nvpair_t *elem; 270 nvlist_t *args; 271 int error; 272 char pool[MAXNAMELEN]; 273 274 /* determine the pool name */ 275 elem = nvlist_next_nvpair(snaps, NULL); 276 if (elem == NULL) 277 return (0); 278 (void) strlcpy(pool, nvpair_name(elem), sizeof (pool)); 279 pool[strcspn(pool, "/@")] = '\0'; 280 281 args = fnvlist_alloc(); 282 fnvlist_add_nvlist(args, "snaps", snaps); 283 if (defer) 284 fnvlist_add_boolean(args, "defer"); 285 286 error = lzc_ioctl(ZFS_IOC_DESTROY_SNAPS, pool, args, errlist); 287 nvlist_free(args); 288 289 return (error); 290 } 291 292 int 293 lzc_snaprange_space(const char *firstsnap, const char *lastsnap, 294 uint64_t *usedp) 295 { 296 nvlist_t *args; 297 nvlist_t *result; 298 int err; 299 char fs[MAXNAMELEN]; 300 char *atp; 301 302 /* determine the fs name */ 303 (void) strlcpy(fs, firstsnap, sizeof (fs)); 304 atp = strchr(fs, '@'); 305 if (atp == NULL) 306 return (EINVAL); 307 *atp = '\0'; 308 309 args = fnvlist_alloc(); 310 fnvlist_add_string(args, "firstsnap", firstsnap); 311 312 err = lzc_ioctl(ZFS_IOC_SPACE_SNAPS, lastsnap, args, &result); 313 nvlist_free(args); 314 if (err == 0) 315 *usedp = fnvlist_lookup_uint64(result, "used"); 316 fnvlist_free(result); 317 318 return (err); 319 } 320 321 boolean_t 322 lzc_exists(const char *dataset) 323 { 324 /* 325 * The objset_stats ioctl is still legacy, so we need to construct our 326 * own zfs_cmd_t rather than using zfsc_ioctl(). 327 */ 328 zfs_cmd_t zc = { 0 }; 329 330 (void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name)); 331 return (ioctl(g_fd, ZFS_IOC_OBJSET_STATS, &zc) == 0); 332 } 333 334 /* 335 * Create "user holds" on snapshots. If there is a hold on a snapshot, 336 * the snapshot can not be destroyed. (However, it can be marked for deletion 337 * by lzc_destroy_snaps(defer=B_TRUE).) 338 * 339 * The keys in the nvlist are snapshot names. 340 * The snapshots must all be in the same pool. 341 * The value is the name of the hold (string type). 342 * 343 * If cleanup_fd is not -1, it must be the result of open("/dev/zfs", O_EXCL). 344 * In this case, when the cleanup_fd is closed (including on process 345 * termination), the holds will be released. If the system is shut down 346 * uncleanly, the holds will be released when the pool is next opened 347 * or imported. 348 * 349 * Holds for snapshots which don't exist will be skipped and have an entry 350 * added to errlist, but will not cause an overall failure. 351 * 352 * The return value will be 0 if all holds, for snapshots that existed, 353 * were succesfully created. 354 * 355 * Otherwise the return value will be the errno of a (unspecified) hold that 356 * failed and no holds will be created. 357 * 358 * In all cases the errlist will have an entry for each hold that failed 359 * (name = snapshot), with its value being the error code (int32). 360 */ 361 int 362 lzc_hold(nvlist_t *holds, int cleanup_fd, nvlist_t **errlist) 363 { 364 char pool[MAXNAMELEN]; 365 nvlist_t *args; 366 nvpair_t *elem; 367 int error; 368 369 /* determine the pool name */ 370 elem = nvlist_next_nvpair(holds, NULL); 371 if (elem == NULL) 372 return (0); 373 (void) strlcpy(pool, nvpair_name(elem), sizeof (pool)); 374 pool[strcspn(pool, "/@")] = '\0'; 375 376 args = fnvlist_alloc(); 377 fnvlist_add_nvlist(args, "holds", holds); 378 if (cleanup_fd != -1) 379 fnvlist_add_int32(args, "cleanup_fd", cleanup_fd); 380 381 error = lzc_ioctl(ZFS_IOC_HOLD, pool, args, errlist); 382 nvlist_free(args); 383 return (error); 384 } 385 386 /* 387 * Release "user holds" on snapshots. If the snapshot has been marked for 388 * deferred destroy (by lzc_destroy_snaps(defer=B_TRUE)), it does not have 389 * any clones, and all the user holds are removed, then the snapshot will be 390 * destroyed. 391 * 392 * The keys in the nvlist are snapshot names. 393 * The snapshots must all be in the same pool. 394 * The value is a nvlist whose keys are the holds to remove. 395 * 396 * Holds which failed to release because they didn't exist will have an entry 397 * added to errlist, but will not cause an overall failure. 398 * 399 * The return value will be 0 if the nvl holds was empty or all holds that 400 * existed, were successfully removed. 401 * 402 * Otherwise the return value will be the errno of a (unspecified) hold that 403 * failed to release and no holds will be released. 404 * 405 * In all cases the errlist will have an entry for each hold that failed to 406 * to release. 407 */ 408 int 409 lzc_release(nvlist_t *holds, nvlist_t **errlist) 410 { 411 char pool[MAXNAMELEN]; 412 nvpair_t *elem; 413 414 /* determine the pool name */ 415 elem = nvlist_next_nvpair(holds, NULL); 416 if (elem == NULL) 417 return (0); 418 (void) strlcpy(pool, nvpair_name(elem), sizeof (pool)); 419 pool[strcspn(pool, "/@")] = '\0'; 420 421 return (lzc_ioctl(ZFS_IOC_RELEASE, pool, holds, errlist)); 422 } 423 424 /* 425 * Retrieve list of user holds on the specified snapshot. 426 * 427 * On success, *holdsp will be set to a nvlist which the caller must free. 428 * The keys are the names of the holds, and the value is the creation time 429 * of the hold (uint64) in seconds since the epoch. 430 */ 431 int 432 lzc_get_holds(const char *snapname, nvlist_t **holdsp) 433 { 434 int error; 435 nvlist_t *innvl = fnvlist_alloc(); 436 error = lzc_ioctl(ZFS_IOC_GET_HOLDS, snapname, innvl, holdsp); 437 fnvlist_free(innvl); 438 return (error); 439 } 440 441 /* 442 * If fromsnap is NULL, a full (non-incremental) stream will be sent. 443 */ 444 int 445 lzc_send(const char *snapname, const char *fromsnap, int fd) 446 { 447 nvlist_t *args; 448 int err; 449 450 args = fnvlist_alloc(); 451 fnvlist_add_int32(args, "fd", fd); 452 if (fromsnap != NULL) 453 fnvlist_add_string(args, "fromsnap", fromsnap); 454 err = lzc_ioctl(ZFS_IOC_SEND_NEW, snapname, args, NULL); 455 nvlist_free(args); 456 return (err); 457 } 458 459 /* 460 * If fromsnap is NULL, a full (non-incremental) stream will be estimated. 461 */ 462 int 463 lzc_send_space(const char *snapname, const char *fromsnap, uint64_t *spacep) 464 { 465 nvlist_t *args; 466 nvlist_t *result; 467 int err; 468 469 args = fnvlist_alloc(); 470 if (fromsnap != NULL) 471 fnvlist_add_string(args, "fromsnap", fromsnap); 472 err = lzc_ioctl(ZFS_IOC_SEND_SPACE, snapname, args, &result); 473 nvlist_free(args); 474 if (err == 0) 475 *spacep = fnvlist_lookup_uint64(result, "space"); 476 nvlist_free(result); 477 return (err); 478 } 479 480 static int 481 recv_read(int fd, void *buf, int ilen) 482 { 483 char *cp = buf; 484 int rv; 485 int len = ilen; 486 487 do { 488 rv = read(fd, cp, len); 489 cp += rv; 490 len -= rv; 491 } while (rv > 0); 492 493 if (rv < 0 || len != 0) 494 return (EIO); 495 496 return (0); 497 } 498 499 /* 500 * The simplest receive case: receive from the specified fd, creating the 501 * specified snapshot. Apply the specified properties a "received" properties 502 * (which can be overridden by locally-set properties). If the stream is a 503 * clone, its origin snapshot must be specified by 'origin'. The 'force' 504 * flag will cause the target filesystem to be rolled back or destroyed if 505 * necessary to receive. 506 * 507 * Return 0 on success or an errno on failure. 508 * 509 * Note: this interface does not work on dedup'd streams 510 * (those with DMU_BACKUP_FEATURE_DEDUP). 511 */ 512 int 513 lzc_receive(const char *snapname, nvlist_t *props, const char *origin, 514 boolean_t force, int fd) 515 { 516 /* 517 * The receive ioctl is still legacy, so we need to construct our own 518 * zfs_cmd_t rather than using zfsc_ioctl(). 519 */ 520 zfs_cmd_t zc = { 0 }; 521 char *atp; 522 char *packed = NULL; 523 size_t size; 524 dmu_replay_record_t drr; 525 int error; 526 527 ASSERT3S(g_refcount, >, 0); 528 529 /* zc_name is name of containing filesystem */ 530 (void) strlcpy(zc.zc_name, snapname, sizeof (zc.zc_name)); 531 atp = strchr(zc.zc_name, '@'); 532 if (atp == NULL) 533 return (EINVAL); 534 *atp = '\0'; 535 536 /* if the fs does not exist, try its parent. */ 537 if (!lzc_exists(zc.zc_name)) { 538 char *slashp = strrchr(zc.zc_name, '/'); 539 if (slashp == NULL) 540 return (ENOENT); 541 *slashp = '\0'; 542 543 } 544 545 /* zc_value is full name of the snapshot to create */ 546 (void) strlcpy(zc.zc_value, snapname, sizeof (zc.zc_value)); 547 548 if (props != NULL) { 549 /* zc_nvlist_src is props to set */ 550 packed = fnvlist_pack(props, &size); 551 zc.zc_nvlist_src = (uint64_t)(uintptr_t)packed; 552 zc.zc_nvlist_src_size = size; 553 } 554 555 /* zc_string is name of clone origin (if DRR_FLAG_CLONE) */ 556 if (origin != NULL) 557 (void) strlcpy(zc.zc_string, origin, sizeof (zc.zc_string)); 558 559 /* zc_begin_record is non-byteswapped BEGIN record */ 560 error = recv_read(fd, &drr, sizeof (drr)); 561 if (error != 0) 562 goto out; 563 zc.zc_begin_record = drr.drr_u.drr_begin; 564 565 /* zc_cookie is fd to read from */ 566 zc.zc_cookie = fd; 567 568 /* zc guid is force flag */ 569 zc.zc_guid = force; 570 571 /* zc_cleanup_fd is unused */ 572 zc.zc_cleanup_fd = -1; 573 574 error = ioctl(g_fd, ZFS_IOC_RECV, &zc); 575 if (error != 0) 576 error = errno; 577 578 out: 579 if (packed != NULL) 580 fnvlist_pack_free(packed, size); 581 free((void*)(uintptr_t)zc.zc_nvlist_dst); 582 return (error); 583 } 584 585 /* 586 * Roll back this filesystem or volume to its most recent snapshot. 587 * If snapnamebuf is not NULL, it will be filled in with the name 588 * of the most recent snapshot. 589 * 590 * Return 0 on success or an errno on failure. 591 */ 592 int 593 lzc_rollback(const char *fsname, char *snapnamebuf, int snapnamelen) 594 { 595 nvlist_t *args; 596 nvlist_t *result; 597 int err; 598 599 args = fnvlist_alloc(); 600 err = lzc_ioctl(ZFS_IOC_ROLLBACK, fsname, args, &result); 601 nvlist_free(args); 602 if (err == 0 && snapnamebuf != NULL) { 603 const char *snapname = fnvlist_lookup_string(result, "target"); 604 (void) strlcpy(snapnamebuf, snapname, snapnamelen); 605 } 606 return (err); 607 }