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