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