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