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