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 */
27
28 /*
29 * zfs diff support
30 */
31 #include <ctype.h>
32 #include <errno.h>
33 #include <libintl.h>
34 #include <string.h>
35 #include <sys/types.h>
36 #include <sys/stat.h>
37 #include <fcntl.h>
38 #include <attr.h>
39 #include <stddef.h>
40 #include <unistd.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <stropts.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 static boolean_t
do_name_cmp(const char * fpath,const char * tpath)59 do_name_cmp(const char *fpath, const char *tpath)
60 {
61 char *fname, *tname;
62 fname = strrchr(fpath, '/') + 1;
63 tname = strrchr(tpath, '/') + 1;
64 return (strcmp(fname, tname) == 0);
65 }
66
67 typedef struct differ_info {
68 zfs_handle_t *zhp;
69 char *fromsnap;
70 char *frommnt;
71 char *tosnap;
72 char *tomnt;
73 char *ds;
74 char *dsmnt;
75 char *tmpsnap;
76 char errbuf[1024];
77 boolean_t isclone;
78 boolean_t scripted;
79 boolean_t classify;
80 boolean_t timestamped;
81 uint64_t shares;
82 int zerr;
83 int cleanupfd;
84 int outputfd;
85 int datafd;
86 } differ_info_t;
87
88 /*
89 * Given a {dsname, object id}, get the object path
90 */
91 static int
get_stats_for_obj(differ_info_t * di,const char * dsname,uint64_t obj,char * pn,int maxlen,zfs_stat_t * sb)92 get_stats_for_obj(differ_info_t *di, const char *dsname, uint64_t obj,
93 char *pn, int maxlen, zfs_stat_t *sb)
94 {
95 zfs_cmd_t zc = { 0 };
96 int error;
97
98 (void) strlcpy(zc.zc_name, dsname, sizeof (zc.zc_name));
99 zc.zc_obj = obj;
100
101 errno = 0;
102 error = ioctl(di->zhp->zfs_hdl->libzfs_fd, ZFS_IOC_OBJ_TO_STATS, &zc);
103 di->zerr = errno;
104
105 /* we can get stats even if we failed to get a path */
106 (void) memcpy(sb, &zc.zc_stat, sizeof (zfs_stat_t));
107 if (error == 0) {
108 ASSERT(di->zerr == 0);
109 (void) strlcpy(pn, zc.zc_value, maxlen);
110 return (0);
111 }
112
113 if (di->zerr == EPERM) {
114 (void) snprintf(di->errbuf, sizeof (di->errbuf),
115 dgettext(TEXT_DOMAIN,
116 "The sys_config privilege or diff delegated permission "
117 "is needed\nto discover path names"));
118 return (-1);
119 } else {
120 (void) snprintf(di->errbuf, sizeof (di->errbuf),
121 dgettext(TEXT_DOMAIN,
122 "Unable to determine path or stats for "
123 "object %lld in %s"), obj, dsname);
124 return (-1);
125 }
126 }
127
128 /*
129 * stream_bytes
130 *
131 * Prints a file name out a character at a time. If the character is
132 * not in the range of what we consider "printable" ASCII, display it
133 * as an escaped 3-digit octal value. ASCII values less than a space
134 * are all control characters and we declare the upper end as the
135 * DELete character. This also is the last 7-bit ASCII character.
136 * We choose to treat all 8-bit ASCII as not printable for this
137 * application.
138 */
139 static void
stream_bytes(FILE * fp,const char * string)140 stream_bytes(FILE *fp, const char *string)
141 {
142 while (*string) {
143 if (*string > ' ' && *string != '\\' && *string < '\177')
144 (void) fprintf(fp, "%c", *string++);
145 else
146 (void) fprintf(fp, "\\%03o", *string++);
147 }
148 }
149
150 static void
print_what(FILE * fp,mode_t what)151 print_what(FILE *fp, mode_t what)
152 {
153 char symbol;
154
155 switch (what & S_IFMT) {
156 case S_IFBLK:
157 symbol = 'B';
158 break;
159 case S_IFCHR:
160 symbol = 'C';
161 break;
162 case S_IFDIR:
163 symbol = '/';
164 break;
165 case S_IFDOOR:
166 symbol = '>';
167 break;
168 case S_IFIFO:
169 symbol = '|';
170 break;
171 case S_IFLNK:
172 symbol = '@';
173 break;
174 case S_IFPORT:
175 symbol = 'P';
176 break;
177 case S_IFSOCK:
178 symbol = '=';
179 break;
180 case S_IFREG:
181 symbol = 'F';
182 break;
183 default:
184 symbol = '?';
185 break;
186 }
187 (void) fprintf(fp, "%c", symbol);
188 }
189
190 static void
print_cmn(FILE * fp,differ_info_t * di,const char * file)191 print_cmn(FILE *fp, differ_info_t *di, const char *file)
192 {
193 stream_bytes(fp, di->dsmnt);
194 stream_bytes(fp, file);
195 }
196
197 static void
print_rename(FILE * fp,differ_info_t * di,const char * old,const char * new,zfs_stat_t * isb)198 print_rename(FILE *fp, differ_info_t *di, const char *old, const char *new,
199 zfs_stat_t *isb)
200 {
201 if (di->timestamped)
202 (void) fprintf(fp, "%10lld.%09lld\t",
203 (longlong_t)isb->zs_ctime[0],
204 (longlong_t)isb->zs_ctime[1]);
205 (void) fprintf(fp, "%c\t", ZDIFF_RENAMED);
206 if (di->classify) {
207 print_what(fp, isb->zs_mode);
208 (void) fprintf(fp, "\t");
209 }
210 print_cmn(fp, di, old);
211 if (di->scripted)
212 (void) fprintf(fp, "\t");
213 else
214 (void) fprintf(fp, " -> ");
215 print_cmn(fp, di, new);
216 (void) fprintf(fp, "\n");
217 }
218
219 static void
print_link_change(FILE * fp,differ_info_t * di,int delta,const char * file,zfs_stat_t * isb)220 print_link_change(FILE *fp, differ_info_t *di, int delta, const char *file,
221 zfs_stat_t *isb)
222 {
223 if (di->timestamped)
224 (void) fprintf(fp, "%10lld.%09lld\t",
225 (longlong_t)isb->zs_ctime[0],
226 (longlong_t)isb->zs_ctime[1]);
227 (void) fprintf(fp, "%c\t", ZDIFF_MODIFIED);
228 if (di->classify) {
229 print_what(fp, isb->zs_mode);
230 (void) fprintf(fp, "\t");
231 }
232 print_cmn(fp, di, file);
233 (void) fprintf(fp, "\t(%+d)", delta);
234 (void) fprintf(fp, "\n");
235 }
236
237 static void
print_file(FILE * fp,differ_info_t * di,char type,const char * file,zfs_stat_t * isb)238 print_file(FILE *fp, differ_info_t *di, char type, const char *file,
239 zfs_stat_t *isb)
240 {
241 if (di->timestamped)
242 (void) fprintf(fp, "%10lld.%09lld\t",
243 (longlong_t)isb->zs_ctime[0],
244 (longlong_t)isb->zs_ctime[1]);
245 (void) fprintf(fp, "%c\t", type);
246 if (di->classify) {
247 print_what(fp, isb->zs_mode);
248 (void) fprintf(fp, "\t");
249 }
250 print_cmn(fp, di, file);
251 (void) fprintf(fp, "\n");
252 }
253
254 static int
write_inuse_diffs_one(FILE * fp,differ_info_t * di,uint64_t dobj)255 write_inuse_diffs_one(FILE *fp, differ_info_t *di, uint64_t dobj)
256 {
257 struct zfs_stat fsb, tsb;
258 boolean_t same_name;
259 mode_t fmode, tmode;
260 char fobjname[MAXPATHLEN], tobjname[MAXPATHLEN];
261 int fobjerr, tobjerr;
262 int change;
263
264 if (dobj == di->shares)
265 return (0);
266
267 /*
268 * Check the from and to snapshots for info on the object. If
269 * we get ENOENT, then the object just didn't exist in that
270 * snapshot. If we get ENOTSUP, then we tried to get
271 * info on a non-ZPL object, which we don't care about anyway.
272 */
273 fobjerr = get_stats_for_obj(di, di->fromsnap, dobj, fobjname,
274 MAXPATHLEN, &fsb);
275 if (fobjerr && di->zerr != ENOENT && di->zerr != ENOTSUP)
276 return (-1);
277
278 tobjerr = get_stats_for_obj(di, di->tosnap, dobj, tobjname,
279 MAXPATHLEN, &tsb);
280 if (tobjerr && di->zerr != ENOENT && di->zerr != ENOTSUP)
281 return (-1);
282
283 /*
284 * Unallocated object sharing the same meta dnode block
285 */
286 if (fobjerr && tobjerr) {
287 ASSERT(di->zerr == ENOENT || di->zerr == ENOTSUP);
288 di->zerr = 0;
289 return (0);
290 }
291
292 di->zerr = 0; /* negate get_stats_for_obj() from side that failed */
293 fmode = fsb.zs_mode & S_IFMT;
294 tmode = tsb.zs_mode & S_IFMT;
295 if (fmode == S_IFDIR || tmode == S_IFDIR || fsb.zs_links == 0 ||
296 tsb.zs_links == 0)
297 change = 0;
298 else
299 change = tsb.zs_links - fsb.zs_links;
300
301 if (fobjerr) {
302 if (change) {
303 print_link_change(fp, di, change, tobjname, &tsb);
304 return (0);
305 }
306 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
307 return (0);
308 } else if (tobjerr) {
309 if (change) {
310 print_link_change(fp, di, change, fobjname, &fsb);
311 return (0);
312 }
313 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
314 return (0);
315 }
316
317 if (fmode != tmode && fsb.zs_gen == tsb.zs_gen)
318 tsb.zs_gen++; /* Force a generational difference */
319 same_name = do_name_cmp(fobjname, tobjname);
320
321 /* Simple modification or no change */
322 if (fsb.zs_gen == tsb.zs_gen) {
323 /* No apparent changes. Could we assert !this? */
324 if (fsb.zs_ctime[0] == tsb.zs_ctime[0] &&
325 fsb.zs_ctime[1] == tsb.zs_ctime[1])
326 return (0);
327 if (change) {
328 print_link_change(fp, di, change,
329 change > 0 ? fobjname : tobjname, &tsb);
330 } else if (same_name) {
331 print_file(fp, di, ZDIFF_MODIFIED, fobjname, &tsb);
332 } else {
333 print_rename(fp, di, fobjname, tobjname, &tsb);
334 }
335 return (0);
336 } else {
337 /* file re-created or object re-used */
338 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
339 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
340 return (0);
341 }
342 }
343
344 static int
write_inuse_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)345 write_inuse_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
346 {
347 uint64_t o;
348 int err;
349
350 for (o = dr->ddr_first; o <= dr->ddr_last; o++) {
351 if (err = write_inuse_diffs_one(fp, di, o))
352 return (err);
353 }
354 return (0);
355 }
356
357 static int
describe_free(FILE * fp,differ_info_t * di,uint64_t object,char * namebuf,int maxlen)358 describe_free(FILE *fp, differ_info_t *di, uint64_t object, char *namebuf,
359 int maxlen)
360 {
361 struct zfs_stat sb;
362
363 if (get_stats_for_obj(di, di->fromsnap, object, namebuf,
364 maxlen, &sb) != 0) {
365 /* Let it slide, if in the delete queue on from side */
366 if (di->zerr == ENOENT && sb.zs_links == 0) {
367 di->zerr = 0;
368 return (0);
369 }
370 return (-1);
371 }
372
373 print_file(fp, di, ZDIFF_REMOVED, namebuf, &sb);
374 return (0);
375 }
376
377 static int
write_free_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)378 write_free_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
379 {
380 zfs_cmd_t zc = { 0 };
381 libzfs_handle_t *lhdl = di->zhp->zfs_hdl;
382 char fobjname[MAXPATHLEN];
383
384 (void) strlcpy(zc.zc_name, di->fromsnap, sizeof (zc.zc_name));
385 zc.zc_obj = dr->ddr_first - 1;
386
387 ASSERT(di->zerr == 0);
388
389 while (zc.zc_obj < dr->ddr_last) {
390 int err;
391
392 err = ioctl(lhdl->libzfs_fd, ZFS_IOC_NEXT_OBJ, &zc);
393 if (err == 0) {
394 if (zc.zc_obj == di->shares) {
395 zc.zc_obj++;
396 continue;
397 }
398 if (zc.zc_obj > dr->ddr_last) {
399 break;
400 }
401 err = describe_free(fp, di, zc.zc_obj, fobjname,
402 MAXPATHLEN);
403 if (err)
404 break;
405 } else if (errno == ESRCH) {
406 break;
407 } else {
408 (void) snprintf(di->errbuf, sizeof (di->errbuf),
409 dgettext(TEXT_DOMAIN,
410 "next allocated object (> %lld) find failure"),
411 zc.zc_obj);
412 di->zerr = errno;
413 break;
414 }
415 }
416 if (di->zerr)
417 return (-1);
418 return (0);
419 }
420
421 static void *
differ(void * arg)422 differ(void *arg)
423 {
424 differ_info_t *di = arg;
425 dmu_diff_record_t dr;
426 FILE *ofp;
427 int err = 0;
428
429 if ((ofp = fdopen(di->outputfd, "w")) == NULL) {
430 di->zerr = errno;
431 (void) strerror_r(errno, di->errbuf, sizeof (di->errbuf));
432 (void) close(di->datafd);
433 return ((void *)-1);
434 }
435
436 for (;;) {
437 char *cp = (char *)&dr;
438 int len = sizeof (dr);
439 int rv;
440
441 do {
442 rv = read(di->datafd, cp, len);
443 cp += rv;
444 len -= rv;
445 } while (len > 0 && rv > 0);
446
447 if (rv < 0 || (rv == 0 && len != sizeof (dr))) {
448 di->zerr = EPIPE;
449 break;
450 } else if (rv == 0) {
451 /* end of file at a natural breaking point */
452 break;
453 }
454
455 switch (dr.ddr_type) {
456 case DDR_FREE:
457 err = write_free_diffs(ofp, di, &dr);
458 break;
459 case DDR_INUSE:
460 err = write_inuse_diffs(ofp, di, &dr);
461 break;
462 default:
463 di->zerr = EPIPE;
464 break;
465 }
466
467 if (err || di->zerr)
468 break;
469 }
470
471 (void) fclose(ofp);
472 (void) close(di->datafd);
473 if (err)
474 return ((void *)-1);
475 if (di->zerr) {
476 ASSERT(di->zerr == EINVAL);
477 (void) snprintf(di->errbuf, sizeof (di->errbuf),
478 dgettext(TEXT_DOMAIN,
479 "Internal error: bad data from diff IOCTL"));
480 return ((void *)-1);
481 }
482 return ((void *)0);
483 }
484
485 static int
find_shares_object(differ_info_t * di)486 find_shares_object(differ_info_t *di)
487 {
488 char fullpath[MAXPATHLEN];
489 struct stat64 sb = { 0 };
490
491 (void) strlcpy(fullpath, di->dsmnt, MAXPATHLEN);
492 (void) strlcat(fullpath, ZDIFF_SHARESDIR, MAXPATHLEN);
493
494 if (stat64(fullpath, &sb) != 0) {
495 (void) snprintf(di->errbuf, sizeof (di->errbuf),
496 dgettext(TEXT_DOMAIN, "Cannot stat %s"), fullpath);
497 return (zfs_error(di->zhp->zfs_hdl, EZFS_DIFF, di->errbuf));
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