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) 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
25 * Copyright (c) 2015, 2018 by Delphix. All rights reserved.
26 * Copyright 2016 Joyent, Inc.
27 * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
28 */
29
30 /*
31 * zfs diff support
32 */
33 #include <ctype.h>
34 #include <errno.h>
35 #include <libintl.h>
36 #include <string.h>
37 #include <sys/types.h>
38 #include <sys/stat.h>
39 #include <fcntl.h>
40 #include <attr.h>
41 #include <stddef.h>
42 #include <unistd.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <stropts.h>
46 #include <pthread.h>
47 #include <sys/zfs_ioctl.h>
48 #include <libzfs.h>
49 #include "libzfs_impl.h"
50
51 #define ZDIFF_SNAPDIR "/.zfs/snapshot/"
52 #define ZDIFF_SHARESDIR "/.zfs/shares/"
53 #define ZDIFF_PREFIX "zfs-diff-%d"
54
55 #define ZDIFF_ADDED '+'
56 #define ZDIFF_MODIFIED 'M'
57 #define ZDIFF_REMOVED '-'
58 #define ZDIFF_RENAMED 'R'
59
60 typedef struct differ_info {
61 zfs_handle_t *zhp;
62 char *fromsnap;
63 char *frommnt;
64 char *tosnap;
65 char *tomnt;
66 char *ds;
67 char *dsmnt;
68 char *tmpsnap;
69 char errbuf[1024];
70 boolean_t isclone;
71 boolean_t scripted;
72 boolean_t classify;
73 boolean_t timestamped;
74 uint64_t shares;
75 int zerr;
76 int cleanupfd;
77 int outputfd;
78 int datafd;
79 } differ_info_t;
80
81 /*
82 * Given a {dsname, object id}, get the object path
83 */
84 static int
get_stats_for_obj(differ_info_t * di,const char * dsname,uint64_t obj,char * pn,int maxlen,zfs_stat_t * sb)85 get_stats_for_obj(differ_info_t *di, const char *dsname, uint64_t obj,
86 char *pn, int maxlen, zfs_stat_t *sb)
87 {
88 zfs_cmd_t zc = { 0 };
89 int error;
90
91 (void) strlcpy(zc.zc_name, dsname, sizeof (zc.zc_name));
92 zc.zc_obj = obj;
93
94 errno = 0;
95 error = ioctl(di->zhp->zfs_hdl->libzfs_fd, ZFS_IOC_OBJ_TO_STATS, &zc);
96 di->zerr = errno;
97
98 /* we can get stats even if we failed to get a path */
99 (void) memcpy(sb, &zc.zc_stat, sizeof (zfs_stat_t));
100 if (error == 0) {
101 ASSERT(di->zerr == 0);
102 (void) strlcpy(pn, zc.zc_value, maxlen);
103 return (0);
104 }
105
106 if (di->zerr == ESTALE) {
107 (void) snprintf(pn, maxlen, "(on_delete_queue)");
108 return (0);
109 } else if (di->zerr == EPERM) {
110 (void) snprintf(di->errbuf, sizeof (di->errbuf),
111 dgettext(TEXT_DOMAIN,
112 "The sys_config privilege or diff delegated permission "
113 "is needed\nto discover path names"));
114 return (-1);
115 } else if (di->zerr == EACCES) {
116 (void) snprintf(di->errbuf, sizeof (di->errbuf),
117 dgettext(TEXT_DOMAIN,
118 "Key must be loaded to discover path names"));
119 return (-1);
120 } else {
121 (void) snprintf(di->errbuf, sizeof (di->errbuf),
122 dgettext(TEXT_DOMAIN,
123 "Unable to determine path or stats for "
124 "object %lld in %s"), obj, dsname);
125 return (-1);
126 }
127 }
128
129 /*
130 * stream_bytes
131 *
132 * Prints a file name out a character at a time. If the character is
133 * not in the range of what we consider "printable" ASCII, display it
134 * as an escaped 3-digit octal value. ASCII values less than a space
135 * are all control characters and we declare the upper end as the
136 * DELete character. This also is the last 7-bit ASCII character.
137 * We choose to treat all 8-bit ASCII as not printable for this
138 * application.
139 */
140 static void
stream_bytes(FILE * fp,const char * string)141 stream_bytes(FILE *fp, const char *string)
142 {
143 char c;
144
145 while ((c = *string++) != '\0') {
146 if (c > ' ' && c != '\\' && c < '\177') {
147 (void) fprintf(fp, "%c", c);
148 } else {
149 (void) fprintf(fp, "\\%03o", (uint8_t)c);
150 }
151 }
152 }
153
154 static void
print_what(FILE * fp,mode_t what)155 print_what(FILE *fp, mode_t what)
156 {
157 char symbol;
158
159 switch (what & S_IFMT) {
160 case S_IFBLK:
161 symbol = 'B';
162 break;
163 case S_IFCHR:
164 symbol = 'C';
165 break;
166 case S_IFDIR:
167 symbol = '/';
168 break;
169 case S_IFDOOR:
170 symbol = '>';
171 break;
172 case S_IFIFO:
173 symbol = '|';
174 break;
175 case S_IFLNK:
176 symbol = '@';
177 break;
178 case S_IFPORT:
179 symbol = 'P';
180 break;
181 case S_IFSOCK:
182 symbol = '=';
183 break;
184 case S_IFREG:
185 symbol = 'F';
186 break;
187 default:
188 symbol = '?';
189 break;
190 }
191 (void) fprintf(fp, "%c", symbol);
192 }
193
194 static void
print_cmn(FILE * fp,differ_info_t * di,const char * file)195 print_cmn(FILE *fp, differ_info_t *di, const char *file)
196 {
197 stream_bytes(fp, di->dsmnt);
198 stream_bytes(fp, file);
199 }
200
201 static void
print_rename(FILE * fp,differ_info_t * di,const char * old,const char * new,zfs_stat_t * isb)202 print_rename(FILE *fp, differ_info_t *di, const char *old, const char *new,
203 zfs_stat_t *isb)
204 {
205 if (di->timestamped)
206 (void) fprintf(fp, "%10lld.%09lld\t",
207 (longlong_t)isb->zs_ctime[0],
208 (longlong_t)isb->zs_ctime[1]);
209 (void) fprintf(fp, "%c\t", ZDIFF_RENAMED);
210 if (di->classify) {
211 print_what(fp, isb->zs_mode);
212 (void) fprintf(fp, "\t");
213 }
214 print_cmn(fp, di, old);
215 if (di->scripted)
216 (void) fprintf(fp, "\t");
217 else
218 (void) fprintf(fp, " -> ");
219 print_cmn(fp, di, new);
220 (void) fprintf(fp, "\n");
221 }
222
223 static void
print_link_change(FILE * fp,differ_info_t * di,int delta,const char * file,zfs_stat_t * isb)224 print_link_change(FILE *fp, differ_info_t *di, int delta, const char *file,
225 zfs_stat_t *isb)
226 {
227 if (di->timestamped)
228 (void) fprintf(fp, "%10lld.%09lld\t",
229 (longlong_t)isb->zs_ctime[0],
230 (longlong_t)isb->zs_ctime[1]);
231 (void) fprintf(fp, "%c\t", ZDIFF_MODIFIED);
232 if (di->classify) {
233 print_what(fp, isb->zs_mode);
234 (void) fprintf(fp, "\t");
235 }
236 print_cmn(fp, di, file);
237 (void) fprintf(fp, "\t(%+d)", delta);
238 (void) fprintf(fp, "\n");
239 }
240
241 static void
print_file(FILE * fp,differ_info_t * di,char type,const char * file,zfs_stat_t * isb)242 print_file(FILE *fp, differ_info_t *di, char type, const char *file,
243 zfs_stat_t *isb)
244 {
245 if (di->timestamped)
246 (void) fprintf(fp, "%10lld.%09lld\t",
247 (longlong_t)isb->zs_ctime[0],
248 (longlong_t)isb->zs_ctime[1]);
249 (void) fprintf(fp, "%c\t", type);
250 if (di->classify) {
251 print_what(fp, isb->zs_mode);
252 (void) fprintf(fp, "\t");
253 }
254 print_cmn(fp, di, file);
255 (void) fprintf(fp, "\n");
256 }
257
258 static int
write_inuse_diffs_one(FILE * fp,differ_info_t * di,uint64_t dobj)259 write_inuse_diffs_one(FILE *fp, differ_info_t *di, uint64_t dobj)
260 {
261 struct zfs_stat fsb, tsb;
262 mode_t fmode, tmode;
263 char fobjname[MAXPATHLEN], tobjname[MAXPATHLEN];
264 int fobjerr, tobjerr;
265 int change;
266
267 if (dobj == di->shares)
268 return (0);
269
270 /*
271 * Check the from and to snapshots for info on the object. If
272 * we get ENOENT, then the object just didn't exist in that
273 * snapshot. If we get ENOTSUP, then we tried to get
274 * info on a non-ZPL object, which we don't care about anyway.
275 */
276 fobjerr = get_stats_for_obj(di, di->fromsnap, dobj, fobjname,
277 MAXPATHLEN, &fsb);
278 if (fobjerr && di->zerr != ENOENT && di->zerr != ENOTSUP)
279 return (-1);
280
281 tobjerr = get_stats_for_obj(di, di->tosnap, dobj, tobjname,
282 MAXPATHLEN, &tsb);
283 if (tobjerr && di->zerr != ENOENT && di->zerr != ENOTSUP)
284 return (-1);
285
286 /*
287 * Unallocated object sharing the same meta dnode block
288 */
289 if (fobjerr && tobjerr) {
290 ASSERT(di->zerr == ENOENT || di->zerr == ENOTSUP);
291 di->zerr = 0;
292 return (0);
293 }
294
295 di->zerr = 0; /* negate get_stats_for_obj() from side that failed */
296 fmode = fsb.zs_mode & S_IFMT;
297 tmode = tsb.zs_mode & S_IFMT;
298 if (fmode == S_IFDIR || tmode == S_IFDIR || fsb.zs_links == 0 ||
299 tsb.zs_links == 0)
300 change = 0;
301 else
302 change = tsb.zs_links - fsb.zs_links;
303
304 if (fobjerr) {
305 if (change) {
306 print_link_change(fp, di, change, tobjname, &tsb);
307 return (0);
308 }
309 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
310 return (0);
311 } else if (tobjerr) {
312 if (change) {
313 print_link_change(fp, di, change, fobjname, &fsb);
314 return (0);
315 }
316 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
317 return (0);
318 }
319
320 if (fmode != tmode && fsb.zs_gen == tsb.zs_gen)
321 tsb.zs_gen++; /* Force a generational difference */
322
323 /* Simple modification or no change */
324 if (fsb.zs_gen == tsb.zs_gen) {
325 /* No apparent changes. Could we assert !this? */
326 if (fsb.zs_ctime[0] == tsb.zs_ctime[0] &&
327 fsb.zs_ctime[1] == tsb.zs_ctime[1])
328 return (0);
329 if (change) {
330 print_link_change(fp, di, change,
331 change > 0 ? fobjname : tobjname, &tsb);
332 } else if (strcmp(fobjname, tobjname) == 0) {
333 print_file(fp, di, ZDIFF_MODIFIED, fobjname, &tsb);
334 } else {
335 print_rename(fp, di, fobjname, tobjname, &tsb);
336 }
337 return (0);
338 } else {
339 /* file re-created or object re-used */
340 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
341 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
342 return (0);
343 }
344 }
345
346 static int
write_inuse_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)347 write_inuse_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
348 {
349 uint64_t o;
350 int err;
351
352 for (o = dr->ddr_first; o <= dr->ddr_last; o++) {
353 if ((err = write_inuse_diffs_one(fp, di, o)) != 0)
354 return (err);
355 }
356 return (0);
357 }
358
359 static int
describe_free(FILE * fp,differ_info_t * di,uint64_t object,char * namebuf,int maxlen)360 describe_free(FILE *fp, differ_info_t *di, uint64_t object, char *namebuf,
361 int maxlen)
362 {
363 struct zfs_stat sb;
364
365 if (get_stats_for_obj(di, di->fromsnap, object, namebuf,
366 maxlen, &sb) != 0) {
367 return (-1);
368 }
369 /* Don't print if in the delete queue on from side */
370 if (di->zerr == ESTALE) {
371 di->zerr = 0;
372 return (0);
373 }
374
375 print_file(fp, di, ZDIFF_REMOVED, namebuf, &sb);
376 return (0);
377 }
378
379 static int
write_free_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)380 write_free_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
381 {
382 zfs_cmd_t zc = { 0 };
383 libzfs_handle_t *lhdl = di->zhp->zfs_hdl;
384 char fobjname[MAXPATHLEN];
385
386 (void) strlcpy(zc.zc_name, di->fromsnap, sizeof (zc.zc_name));
387 zc.zc_obj = dr->ddr_first - 1;
388
389 ASSERT(di->zerr == 0);
390
391 while (zc.zc_obj < dr->ddr_last) {
392 int err;
393
394 err = ioctl(lhdl->libzfs_fd, ZFS_IOC_NEXT_OBJ, &zc);
395 if (err == 0) {
396 if (zc.zc_obj == di->shares) {
397 zc.zc_obj++;
398 continue;
399 }
400 if (zc.zc_obj > dr->ddr_last) {
401 break;
402 }
403 err = describe_free(fp, di, zc.zc_obj, fobjname,
404 MAXPATHLEN);
405 if (err)
406 break;
407 } else if (errno == ESRCH) {
408 break;
409 } else {
410 (void) snprintf(di->errbuf, sizeof (di->errbuf),
411 dgettext(TEXT_DOMAIN,
412 "next allocated object (> %lld) find failure"),
413 zc.zc_obj);
414 di->zerr = errno;
415 break;
416 }
417 }
418 if (di->zerr)
419 return (-1);
420 return (0);
421 }
422
423 static void *
differ(void * arg)424 differ(void *arg)
425 {
426 differ_info_t *di = arg;
427 dmu_diff_record_t dr;
428 FILE *ofp;
429 int err = 0;
430
431 if ((ofp = fdopen(di->outputfd, "w")) == NULL) {
432 di->zerr = errno;
433 (void) strerror_r(errno, di->errbuf, sizeof (di->errbuf));
434 (void) close(di->datafd);
435 return ((void *)-1);
436 }
437
438 for (;;) {
439 char *cp = (char *)&dr;
440 int len = sizeof (dr);
441 int rv;
442
443 do {
444 rv = read(di->datafd, cp, len);
445 cp += rv;
446 len -= rv;
447 } while (len > 0 && rv > 0);
448
449 if (rv < 0 || (rv == 0 && len != sizeof (dr))) {
450 di->zerr = EPIPE;
451 break;
452 } else if (rv == 0) {
453 /* end of file at a natural breaking point */
454 break;
455 }
456
457 switch (dr.ddr_type) {
458 case DDR_FREE:
459 err = write_free_diffs(ofp, di, &dr);
460 break;
461 case DDR_INUSE:
462 err = write_inuse_diffs(ofp, di, &dr);
463 break;
464 default:
465 di->zerr = EPIPE;
466 break;
467 }
468
469 if (err || di->zerr)
470 break;
471 }
472
473 (void) fclose(ofp);
474 (void) close(di->datafd);
475 if (err)
476 return ((void *)-1);
477 if (di->zerr) {
478 ASSERT(di->zerr == EINVAL);
479 (void) snprintf(di->errbuf, sizeof (di->errbuf),
480 dgettext(TEXT_DOMAIN,
481 "Internal error: bad data from diff IOCTL"));
482 return ((void *)-1);
483 }
484 return ((void *)0);
485 }
486
487 static int
find_shares_object(differ_info_t * di)488 find_shares_object(differ_info_t *di)
489 {
490 char fullpath[MAXPATHLEN];
491 struct stat64 sb = { 0 };
492
493 (void) strlcpy(fullpath, di->dsmnt, MAXPATHLEN);
494 (void) strlcat(fullpath, ZDIFF_SHARESDIR, MAXPATHLEN);
495
496 if (stat64(fullpath, &sb) != 0) {
497 (void) snprintf(di->errbuf, sizeof (di->errbuf),
498 dgettext(TEXT_DOMAIN, "Cannot stat %s"), fullpath);
499 return (zfs_error(di->zhp->zfs_hdl, EZFS_DIFF, di->errbuf));
500 }
501
502 di->shares = (uint64_t)sb.st_ino;
503 return (0);
504 }
505
506 static int
make_temp_snapshot(differ_info_t * di)507 make_temp_snapshot(differ_info_t *di)
508 {
509 libzfs_handle_t *hdl = di->zhp->zfs_hdl;
510 zfs_cmd_t zc = { 0 };
511
512 (void) snprintf(zc.zc_value, sizeof (zc.zc_value),
513 ZDIFF_PREFIX, getpid());
514 (void) strlcpy(zc.zc_name, di->ds, sizeof (zc.zc_name));
515 zc.zc_cleanup_fd = di->cleanupfd;
516
517 if (ioctl(hdl->libzfs_fd, ZFS_IOC_TMP_SNAPSHOT, &zc) != 0) {
518 int err = errno;
519 if (err == EPERM) {
520 (void) snprintf(di->errbuf, sizeof (di->errbuf),
521 dgettext(TEXT_DOMAIN, "The diff delegated "
522 "permission is needed in order\nto create a "
523 "just-in-time snapshot for diffing\n"));
524 return (zfs_error(hdl, EZFS_DIFF, di->errbuf));
525 } else {
526 (void) snprintf(di->errbuf, sizeof (di->errbuf),
527 dgettext(TEXT_DOMAIN, "Cannot create just-in-time "
528 "snapshot of '%s'"), zc.zc_name);
529 return (zfs_standard_error(hdl, err, di->errbuf));
530 }
531 }
532
533 di->tmpsnap = zfs_strdup(hdl, zc.zc_value);
534 di->tosnap = zfs_asprintf(hdl, "%s@%s", di->ds, di->tmpsnap);
535 return (0);
536 }
537
538 static void
teardown_differ_info(differ_info_t * di)539 teardown_differ_info(differ_info_t *di)
540 {
541 free(di->ds);
542 free(di->dsmnt);
543 free(di->fromsnap);
544 free(di->frommnt);
545 free(di->tosnap);
546 free(di->tmpsnap);
547 free(di->tomnt);
548 (void) close(di->cleanupfd);
549 }
550
551 static int
get_snapshot_names(differ_info_t * di,const char * fromsnap,const char * tosnap)552 get_snapshot_names(differ_info_t *di, const char *fromsnap,
553 const char *tosnap)
554 {
555 libzfs_handle_t *hdl = di->zhp->zfs_hdl;
556 char *atptrf = NULL;
557 char *atptrt = NULL;
558 int fdslen, fsnlen;
559 int tdslen, tsnlen;
560
561 /*
562 * Can accept
563 * dataset@snap1
564 * dataset@snap1 dataset@snap2
565 * dataset@snap1 @snap2
566 * dataset@snap1 dataset
567 * @snap1 dataset@snap2
568 */
569 if (tosnap == NULL) {
570 /* only a from snapshot given, must be valid */
571 (void) snprintf(di->errbuf, sizeof (di->errbuf),
572 dgettext(TEXT_DOMAIN,
573 "Badly formed snapshot name %s"), fromsnap);
574
575 if (!zfs_validate_name(hdl, fromsnap, ZFS_TYPE_SNAPSHOT,
576 B_FALSE)) {
577 return (zfs_error(hdl, EZFS_INVALIDNAME,
578 di->errbuf));
579 }
580
581 atptrf = strchr(fromsnap, '@');
582 ASSERT(atptrf != NULL);
583 fdslen = atptrf - fromsnap;
584
585 di->fromsnap = zfs_strdup(hdl, fromsnap);
586 di->ds = zfs_strdup(hdl, fromsnap);
587 di->ds[fdslen] = '\0';
588
589 /* the to snap will be a just-in-time snap of the head */
590 return (make_temp_snapshot(di));
591 }
592
593 (void) snprintf(di->errbuf, sizeof (di->errbuf),
594 dgettext(TEXT_DOMAIN,
595 "Unable to determine which snapshots to compare"));
596
597 atptrf = strchr(fromsnap, '@');
598 atptrt = strchr(tosnap, '@');
599 fdslen = atptrf ? atptrf - fromsnap : strlen(fromsnap);
600 tdslen = atptrt ? atptrt - tosnap : strlen(tosnap);
601 fsnlen = strlen(fromsnap) - fdslen; /* includes @ sign */
602 tsnlen = strlen(tosnap) - tdslen; /* includes @ sign */
603
604 if (fsnlen <= 1 || tsnlen == 1 || (fdslen == 0 && tdslen == 0) ||
605 (fsnlen == 0 && tsnlen == 0)) {
606 return (zfs_error(hdl, EZFS_INVALIDNAME, di->errbuf));
607 } else if ((fdslen > 0 && tdslen > 0) &&
608 ((tdslen != fdslen || strncmp(fromsnap, tosnap, fdslen) != 0))) {
609 /*
610 * not the same dataset name, might be okay if
611 * tosnap is a clone of a fromsnap descendant.
612 */
613 char origin[ZFS_MAX_DATASET_NAME_LEN];
614 zprop_source_t src;
615 zfs_handle_t *zhp;
616
617 di->ds = zfs_alloc(di->zhp->zfs_hdl, tdslen + 1);
618 (void) strncpy(di->ds, tosnap, tdslen);
619 di->ds[tdslen] = '\0';
620
621 zhp = zfs_open(hdl, di->ds, ZFS_TYPE_FILESYSTEM);
622 while (zhp != NULL) {
623 if (zfs_prop_get(zhp, ZFS_PROP_ORIGIN, origin,
624 sizeof (origin), &src, NULL, 0, B_FALSE) != 0) {
625 (void) zfs_close(zhp);
626 zhp = NULL;
627 break;
628 }
629 if (strncmp(origin, fromsnap, fsnlen) == 0)
630 break;
631
632 (void) zfs_close(zhp);
633 zhp = zfs_open(hdl, origin, ZFS_TYPE_FILESYSTEM);
634 }
635
636 if (zhp == NULL) {
637 (void) snprintf(di->errbuf, sizeof (di->errbuf),
638 dgettext(TEXT_DOMAIN,
639 "Not an earlier snapshot from the same fs"));
640 return (zfs_error(hdl, EZFS_INVALIDNAME, di->errbuf));
641 } else {
642 (void) zfs_close(zhp);
643 }
644
645 di->isclone = B_TRUE;
646 di->fromsnap = zfs_strdup(hdl, fromsnap);
647 if (tsnlen) {
648 di->tosnap = zfs_strdup(hdl, tosnap);
649 } else {
650 return (make_temp_snapshot(di));
651 }
652 } else {
653 int dslen = fdslen ? fdslen : tdslen;
654
655 di->ds = zfs_alloc(hdl, dslen + 1);
656 (void) strncpy(di->ds, fdslen ? fromsnap : tosnap, dslen);
657 di->ds[dslen] = '\0';
658
659 di->fromsnap = zfs_asprintf(hdl, "%s%s", di->ds, atptrf);
660 if (tsnlen) {
661 di->tosnap = zfs_asprintf(hdl, "%s%s", di->ds, atptrt);
662 } else {
663 return (make_temp_snapshot(di));
664 }
665 }
666 return (0);
667 }
668
669 static int
get_mountpoint(differ_info_t * di,char * dsnm,char ** mntpt)670 get_mountpoint(differ_info_t *di, char *dsnm, char **mntpt)
671 {
672 boolean_t mounted;
673
674 mounted = is_mounted(di->zhp->zfs_hdl, dsnm, mntpt);
675 if (mounted == B_FALSE) {
676 (void) snprintf(di->errbuf, sizeof (di->errbuf),
677 dgettext(TEXT_DOMAIN,
678 "Cannot diff an unmounted snapshot"));
679 return (zfs_error(di->zhp->zfs_hdl, EZFS_BADTYPE, di->errbuf));
680 }
681
682 /* Avoid a double slash at the beginning of root-mounted datasets */
683 if (**mntpt == '/' && *(*mntpt + 1) == '\0')
684 **mntpt = '\0';
685 return (0);
686 }
687
688 static int
get_mountpoints(differ_info_t * di)689 get_mountpoints(differ_info_t *di)
690 {
691 char *strptr;
692 char *frommntpt;
693
694 /*
695 * first get the mountpoint for the parent dataset
696 */
697 if (get_mountpoint(di, di->ds, &di->dsmnt) != 0)
698 return (-1);
699
700 strptr = strchr(di->tosnap, '@');
701 ASSERT3P(strptr, !=, NULL);
702 di->tomnt = zfs_asprintf(di->zhp->zfs_hdl, "%s%s%s", di->dsmnt,
703 ZDIFF_SNAPDIR, ++strptr);
704
705 strptr = strchr(di->fromsnap, '@');
706 ASSERT3P(strptr, !=, NULL);
707
708 frommntpt = di->dsmnt;
709 if (di->isclone) {
710 char *mntpt;
711 int err;
712
713 *strptr = '\0';
714 err = get_mountpoint(di, di->fromsnap, &mntpt);
715 *strptr = '@';
716 if (err != 0)
717 return (-1);
718 frommntpt = mntpt;
719 }
720
721 di->frommnt = zfs_asprintf(di->zhp->zfs_hdl, "%s%s%s", frommntpt,
722 ZDIFF_SNAPDIR, ++strptr);
723
724 if (di->isclone)
725 free(frommntpt);
726
727 return (0);
728 }
729
730 static int
setup_differ_info(zfs_handle_t * zhp,const char * fromsnap,const char * tosnap,differ_info_t * di)731 setup_differ_info(zfs_handle_t *zhp, const char *fromsnap,
732 const char *tosnap, differ_info_t *di)
733 {
734 di->zhp = zhp;
735
736 di->cleanupfd = open(ZFS_DEV, O_RDWR|O_EXCL);
737 VERIFY(di->cleanupfd >= 0);
738
739 if (get_snapshot_names(di, fromsnap, tosnap) != 0)
740 return (-1);
741
742 if (get_mountpoints(di) != 0)
743 return (-1);
744
745 if (find_shares_object(di) != 0)
746 return (-1);
747
748 return (0);
749 }
750
751 int
zfs_show_diffs(zfs_handle_t * zhp,int outfd,const char * fromsnap,const char * tosnap,int flags)752 zfs_show_diffs(zfs_handle_t *zhp, int outfd, const char *fromsnap,
753 const char *tosnap, int flags)
754 {
755 zfs_cmd_t zc = { 0 };
756 char errbuf[1024];
757 differ_info_t di = { 0 };
758 pthread_t tid;
759 int pipefd[2];
760 int iocerr;
761
762 (void) snprintf(errbuf, sizeof (errbuf),
763 dgettext(TEXT_DOMAIN, "zfs diff failed"));
764
765 if (setup_differ_info(zhp, fromsnap, tosnap, &di)) {
766 teardown_differ_info(&di);
767 return (-1);
768 }
769
770 if (pipe(pipefd)) {
771 zfs_error_aux(zhp->zfs_hdl, strerror(errno));
772 teardown_differ_info(&di);
773 return (zfs_error(zhp->zfs_hdl, EZFS_PIPEFAILED, errbuf));
774 }
775
776 di.scripted = (flags & ZFS_DIFF_PARSEABLE);
777 di.classify = (flags & ZFS_DIFF_CLASSIFY);
778 di.timestamped = (flags & ZFS_DIFF_TIMESTAMP);
779
780 di.outputfd = outfd;
781 di.datafd = pipefd[0];
782
783 if (pthread_create(&tid, NULL, differ, &di)) {
784 zfs_error_aux(zhp->zfs_hdl, strerror(errno));
785 (void) close(pipefd[0]);
786 (void) close(pipefd[1]);
787 teardown_differ_info(&di);
788 return (zfs_error(zhp->zfs_hdl,
789 EZFS_THREADCREATEFAILED, errbuf));
790 }
791
792 /* do the ioctl() */
793 (void) strlcpy(zc.zc_value, di.fromsnap, strlen(di.fromsnap) + 1);
794 (void) strlcpy(zc.zc_name, di.tosnap, strlen(di.tosnap) + 1);
795 zc.zc_cookie = pipefd[1];
796
797 iocerr = ioctl(zhp->zfs_hdl->libzfs_fd, ZFS_IOC_DIFF, &zc);
798 if (iocerr != 0) {
799 (void) snprintf(errbuf, sizeof (errbuf),
800 dgettext(TEXT_DOMAIN, "Unable to obtain diffs"));
801 if (errno == EPERM) {
802 zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
803 "\n The sys_mount privilege or diff delegated "
804 "permission is needed\n to execute the "
805 "diff ioctl"));
806 } else if (errno == EXDEV) {
807 zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
808 "\n Not an earlier snapshot from the same fs"));
809 } else if (errno != EPIPE || di.zerr == 0) {
810 zfs_error_aux(zhp->zfs_hdl, strerror(errno));
811 }
812 (void) close(pipefd[1]);
813 (void) pthread_cancel(tid);
814 (void) pthread_join(tid, NULL);
815 teardown_differ_info(&di);
816 if (di.zerr != 0 && di.zerr != EPIPE) {
817 zfs_error_aux(zhp->zfs_hdl, strerror(di.zerr));
818 return (zfs_error(zhp->zfs_hdl, EZFS_DIFF, di.errbuf));
819 } else {
820 return (zfs_error(zhp->zfs_hdl, EZFS_DIFFDATA, errbuf));
821 }
822 }
823
824 (void) close(pipefd[1]);
825 (void) pthread_join(tid, NULL);
826
827 if (di.zerr != 0) {
828 zfs_error_aux(zhp->zfs_hdl, strerror(di.zerr));
829 return (zfs_error(zhp->zfs_hdl, EZFS_DIFF, di.errbuf));
830 }
831 teardown_differ_info(&di);
832 return (0);
833 }
834