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 <stddef.h>
38 #include <unistd.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <pthread.h>
42 #include <sys/zfs_ioctl.h>
43 #include <libzfs.h>
44 #include "libzfs_impl.h"
45
46 #define ZDIFF_SNAPDIR "/.zfs/snapshot/"
47 #define ZDIFF_SHARESDIR "/.zfs/shares/"
48 #define ZDIFF_PREFIX "zfs-diff-%d"
49
50 #define ZDIFF_ADDED '+'
51 #define ZDIFF_MODIFIED 'M'
52 #define ZDIFF_REMOVED '-'
53 #define ZDIFF_RENAMED 'R'
54
55 static boolean_t
do_name_cmp(const char * fpath,const char * tpath)56 do_name_cmp(const char *fpath, const char *tpath)
57 {
58 char *fname, *tname;
59 fname = strrchr(fpath, '/') + 1;
60 tname = strrchr(tpath, '/') + 1;
61 return (strcmp(fname, tname) == 0);
62 }
63
64 typedef struct differ_info {
65 zfs_handle_t *zhp;
66 char *fromsnap;
67 char *frommnt;
68 char *tosnap;
69 char *tomnt;
70 char *ds;
71 char *dsmnt;
72 char *tmpsnap;
73 char errbuf[1024];
74 boolean_t isclone;
75 boolean_t scripted;
76 boolean_t classify;
77 boolean_t timestamped;
78 uint64_t shares;
79 int zerr;
80 int cleanupfd;
81 int outputfd;
82 int datafd;
83 } differ_info_t;
84
85 /*
86 * Given a {dsname, object id}, get the object path
87 */
88 static int
get_stats_for_obj(differ_info_t * di,const char * dsname,uint64_t obj,char * pn,int maxlen,zfs_stat_t * sb)89 get_stats_for_obj(differ_info_t *di, const char *dsname, uint64_t obj,
90 char *pn, int maxlen, zfs_stat_t *sb)
91 {
92 zfs_cmd_t zc = { 0 };
93 int error;
94
95 (void) strlcpy(zc.zc_name, dsname, sizeof (zc.zc_name));
96 zc.zc_obj = obj;
97
98 errno = 0;
99 error = ioctl(di->zhp->zfs_hdl->libzfs_fd, ZFS_IOC_OBJ_TO_STATS, &zc);
100 di->zerr = errno;
101
102 /* we can get stats even if we failed to get a path */
103 (void) memcpy(sb, &zc.zc_stat, sizeof (zfs_stat_t));
104 if (error == 0) {
105 ASSERT(di->zerr == 0);
106 (void) strlcpy(pn, zc.zc_value, maxlen);
107 return (0);
108 }
109
110 if (di->zerr == EPERM) {
111 (void) snprintf(di->errbuf, sizeof (di->errbuf),
112 dgettext(TEXT_DOMAIN,
113 "The sys_config privilege or diff delegated permission "
114 "is needed\nto discover path names"));
115 return (-1);
116 } else {
117 (void) snprintf(di->errbuf, sizeof (di->errbuf),
118 dgettext(TEXT_DOMAIN,
119 "Unable to determine path or stats for "
120 "object %lld in %s"), obj, dsname);
121 return (-1);
122 }
123 }
124
125 /*
126 * stream_bytes
127 *
128 * Prints a file name out a character at a time. If the character is
129 * not in the range of what we consider "printable" ASCII, display it
130 * as an escaped 3-digit octal value. ASCII values less than a space
131 * are all control characters and we declare the upper end as the
132 * DELete character. This also is the last 7-bit ASCII character.
133 * We choose to treat all 8-bit ASCII as not printable for this
134 * application.
135 */
136 static void
stream_bytes(FILE * fp,const char * string)137 stream_bytes(FILE *fp, const char *string)
138 {
139 while (*string) {
140 if (*string > ' ' && *string != '\\' && *string < '\177')
141 (void) fprintf(fp, "%c", *string++);
142 else {
143 (void) fprintf(fp, "\\%03hho",
144 (unsigned char)*string++);
145 }
146 }
147 }
148
149 static void
print_what(FILE * fp,mode_t what)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 #ifdef S_IFDOOR
165 case S_IFDOOR:
166 symbol = '>';
167 break;
168 #endif
169 case S_IFIFO:
170 symbol = '|';
171 break;
172 case S_IFLNK:
173 symbol = '@';
174 break;
175 #ifdef S_IFPORT
176 case S_IFPORT:
177 symbol = 'P';
178 break;
179 #endif
180 case S_IFSOCK:
181 symbol = '=';
182 break;
183 case S_IFREG:
184 symbol = 'F';
185 break;
186 default:
187 symbol = '?';
188 break;
189 }
190 (void) fprintf(fp, "%c", symbol);
191 }
192
193 static void
print_cmn(FILE * fp,differ_info_t * di,const char * file)194 print_cmn(FILE *fp, differ_info_t *di, const char *file)
195 {
196 stream_bytes(fp, di->dsmnt);
197 stream_bytes(fp, file);
198 }
199
200 static void
print_rename(FILE * fp,differ_info_t * di,const char * old,const char * new,zfs_stat_t * isb)201 print_rename(FILE *fp, differ_info_t *di, const char *old, const char *new,
202 zfs_stat_t *isb)
203 {
204 if (di->timestamped)
205 (void) fprintf(fp, "%10lld.%09lld\t",
206 (longlong_t)isb->zs_ctime[0],
207 (longlong_t)isb->zs_ctime[1]);
208 (void) fprintf(fp, "%c\t", ZDIFF_RENAMED);
209 if (di->classify) {
210 print_what(fp, isb->zs_mode);
211 (void) fprintf(fp, "\t");
212 }
213 print_cmn(fp, di, old);
214 if (di->scripted)
215 (void) fprintf(fp, "\t");
216 else
217 (void) fprintf(fp, " -> ");
218 print_cmn(fp, di, new);
219 (void) fprintf(fp, "\n");
220 }
221
222 static void
print_link_change(FILE * fp,differ_info_t * di,int delta,const char * file,zfs_stat_t * isb)223 print_link_change(FILE *fp, differ_info_t *di, int delta, const char *file,
224 zfs_stat_t *isb)
225 {
226 if (di->timestamped)
227 (void) fprintf(fp, "%10lld.%09lld\t",
228 (longlong_t)isb->zs_ctime[0],
229 (longlong_t)isb->zs_ctime[1]);
230 (void) fprintf(fp, "%c\t", ZDIFF_MODIFIED);
231 if (di->classify) {
232 print_what(fp, isb->zs_mode);
233 (void) fprintf(fp, "\t");
234 }
235 print_cmn(fp, di, file);
236 (void) fprintf(fp, "\t(%+d)", delta);
237 (void) fprintf(fp, "\n");
238 }
239
240 static void
print_file(FILE * fp,differ_info_t * di,char type,const char * file,zfs_stat_t * isb)241 print_file(FILE *fp, differ_info_t *di, char type, const char *file,
242 zfs_stat_t *isb)
243 {
244 if (di->timestamped)
245 (void) fprintf(fp, "%10lld.%09lld\t",
246 (longlong_t)isb->zs_ctime[0],
247 (longlong_t)isb->zs_ctime[1]);
248 (void) fprintf(fp, "%c\t", type);
249 if (di->classify) {
250 print_what(fp, isb->zs_mode);
251 (void) fprintf(fp, "\t");
252 }
253 print_cmn(fp, di, file);
254 (void) fprintf(fp, "\n");
255 }
256
257 static int
write_inuse_diffs_one(FILE * fp,differ_info_t * di,uint64_t dobj)258 write_inuse_diffs_one(FILE *fp, differ_info_t *di, uint64_t dobj)
259 {
260 struct zfs_stat fsb, tsb;
261 boolean_t same_name;
262 mode_t fmode, tmode;
263 char fobjname[MAXPATHLEN], tobjname[MAXPATHLEN];
264 int fobjerr, tobjerr;
265 int change;
266
267 if (dobj == di->shares)
268 return (0);
269
270 /*
271 * Check the from and to snapshots for info on the object. If
272 * we get ENOENT, then the object just didn't exist in that
273 * snapshot. If we get ENOTSUP, then we tried to get
274 * info on a non-ZPL object, which we don't care about anyway.
275 */
276 fobjerr = get_stats_for_obj(di, di->fromsnap, dobj, fobjname,
277 MAXPATHLEN, &fsb);
278 if (fobjerr && di->zerr != ENOENT && di->zerr != ENOTSUP)
279 return (-1);
280
281 tobjerr = get_stats_for_obj(di, di->tosnap, dobj, tobjname,
282 MAXPATHLEN, &tsb);
283 if (tobjerr && di->zerr != ENOENT && di->zerr != ENOTSUP)
284 return (-1);
285
286 /*
287 * Unallocated object sharing the same meta dnode block
288 */
289 if (fobjerr && tobjerr) {
290 ASSERT(di->zerr == ENOENT || di->zerr == ENOTSUP);
291 di->zerr = 0;
292 return (0);
293 }
294
295 di->zerr = 0; /* negate get_stats_for_obj() from side that failed */
296 fmode = fsb.zs_mode & S_IFMT;
297 tmode = tsb.zs_mode & S_IFMT;
298 if (fmode == S_IFDIR || tmode == S_IFDIR || fsb.zs_links == 0 ||
299 tsb.zs_links == 0)
300 change = 0;
301 else
302 change = tsb.zs_links - fsb.zs_links;
303
304 if (fobjerr) {
305 if (change) {
306 print_link_change(fp, di, change, tobjname, &tsb);
307 return (0);
308 }
309 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
310 return (0);
311 } else if (tobjerr) {
312 if (change) {
313 print_link_change(fp, di, change, fobjname, &fsb);
314 return (0);
315 }
316 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
317 return (0);
318 }
319
320 if (fmode != tmode && fsb.zs_gen == tsb.zs_gen)
321 tsb.zs_gen++; /* Force a generational difference */
322 same_name = do_name_cmp(fobjname, tobjname);
323
324 /* Simple modification or no change */
325 if (fsb.zs_gen == tsb.zs_gen) {
326 /* No apparent changes. Could we assert !this? */
327 if (fsb.zs_ctime[0] == tsb.zs_ctime[0] &&
328 fsb.zs_ctime[1] == tsb.zs_ctime[1])
329 return (0);
330 if (change) {
331 print_link_change(fp, di, change,
332 change > 0 ? fobjname : tobjname, &tsb);
333 } else if (same_name) {
334 print_file(fp, di, ZDIFF_MODIFIED, fobjname, &tsb);
335 } else {
336 print_rename(fp, di, fobjname, tobjname, &tsb);
337 }
338 return (0);
339 } else {
340 /* file re-created or object re-used */
341 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
342 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
343 return (0);
344 }
345 }
346
347 static int
write_inuse_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)348 write_inuse_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
349 {
350 uint64_t o;
351 int err;
352
353 for (o = dr->ddr_first; o <= dr->ddr_last; o++) {
354 if (err = write_inuse_diffs_one(fp, di, o))
355 return (err);
356 }
357 return (0);
358 }
359
360 static int
describe_free(FILE * fp,differ_info_t * di,uint64_t object,char * namebuf,int maxlen)361 describe_free(FILE *fp, differ_info_t *di, uint64_t object, char *namebuf,
362 int maxlen)
363 {
364 struct zfs_stat sb;
365
366 if (get_stats_for_obj(di, di->fromsnap, object, namebuf,
367 maxlen, &sb) != 0) {
368 /* Let it slide, if in the delete queue on from side */
369 if (di->zerr == ENOENT && sb.zs_links == 0) {
370 di->zerr = 0;
371 return (0);
372 }
373 return (-1);
374 }
375
376 print_file(fp, di, ZDIFF_REMOVED, namebuf, &sb);
377 return (0);
378 }
379
380 static int
write_free_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)381 write_free_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
382 {
383 zfs_cmd_t zc = { 0 };
384 libzfs_handle_t *lhdl = di->zhp->zfs_hdl;
385 char fobjname[MAXPATHLEN];
386
387 (void) strlcpy(zc.zc_name, di->fromsnap, sizeof (zc.zc_name));
388 zc.zc_obj = dr->ddr_first - 1;
389
390 ASSERT(di->zerr == 0);
391
392 while (zc.zc_obj < dr->ddr_last) {
393 int err;
394
395 err = ioctl(lhdl->libzfs_fd, ZFS_IOC_NEXT_OBJ, &zc);
396 if (err == 0) {
397 if (zc.zc_obj == di->shares) {
398 zc.zc_obj++;
399 continue;
400 }
401 if (zc.zc_obj > dr->ddr_last) {
402 break;
403 }
404 err = describe_free(fp, di, zc.zc_obj, fobjname,
405 MAXPATHLEN);
406 if (err)
407 break;
408 } else if (errno == ESRCH) {
409 break;
410 } else {
411 (void) snprintf(di->errbuf, sizeof (di->errbuf),
412 dgettext(TEXT_DOMAIN,
413 "next allocated object (> %lld) find failure"),
414 zc.zc_obj);
415 di->zerr = errno;
416 break;
417 }
418 }
419 if (di->zerr)
420 return (-1);
421 return (0);
422 }
423
424 static void *
differ(void * arg)425 differ(void *arg)
426 {
427 differ_info_t *di = arg;
428 dmu_diff_record_t dr;
429 FILE *ofp;
430 int err = 0;
431
432 if ((ofp = fdopen(di->outputfd, "w")) == NULL) {
433 di->zerr = errno;
434 (void) strerror_r(errno, di->errbuf, sizeof (di->errbuf));
435 (void) close(di->datafd);
436 return ((void *)-1);
437 }
438
439 for (;;) {
440 char *cp = (char *)&dr;
441 int len = sizeof (dr);
442 int rv;
443
444 do {
445 rv = read(di->datafd, cp, len);
446 cp += rv;
447 len -= rv;
448 } while (len > 0 && rv > 0);
449
450 if (rv < 0 || (rv == 0 && len != sizeof (dr))) {
451 di->zerr = EPIPE;
452 break;
453 } else if (rv == 0) {
454 /* end of file at a natural breaking point */
455 break;
456 }
457
458 switch (dr.ddr_type) {
459 case DDR_FREE:
460 err = write_free_diffs(ofp, di, &dr);
461 break;
462 case DDR_INUSE:
463 err = write_inuse_diffs(ofp, di, &dr);
464 break;
465 default:
466 di->zerr = EPIPE;
467 break;
468 }
469
470 if (err || di->zerr)
471 break;
472 }
473
474 (void) fclose(ofp);
475 (void) close(di->datafd);
476 if (err)
477 return ((void *)-1);
478 if (di->zerr) {
479 ASSERT(di->zerr == EINVAL);
480 (void) snprintf(di->errbuf, sizeof (di->errbuf),
481 dgettext(TEXT_DOMAIN,
482 "Internal error: bad data from diff IOCTL"));
483 return ((void *)-1);
484 }
485 return ((void *)0);
486 }
487
488 static int
find_shares_object(differ_info_t * di)489 find_shares_object(differ_info_t *di)
490 {
491 char fullpath[MAXPATHLEN];
492 struct stat64 sb = { 0 };
493
494 (void) strlcpy(fullpath, di->dsmnt, MAXPATHLEN);
495 (void) strlcat(fullpath, ZDIFF_SHARESDIR, MAXPATHLEN);
496
497 if (stat64(fullpath, &sb) != 0) {
498 #ifdef illumos
499 (void) snprintf(di->errbuf, sizeof (di->errbuf),
500 dgettext(TEXT_DOMAIN, "Cannot stat %s"), fullpath);
501 return (zfs_error(di->zhp->zfs_hdl, EZFS_DIFF, di->errbuf));
502 #else
503 return (0);
504 #endif
505 }
506
507 di->shares = (uint64_t)sb.st_ino;
508 return (0);
509 }
510
511 static int
make_temp_snapshot(differ_info_t * di)512 make_temp_snapshot(differ_info_t *di)
513 {
514 libzfs_handle_t *hdl = di->zhp->zfs_hdl;
515 zfs_cmd_t zc = { 0 };
516
517 (void) snprintf(zc.zc_value, sizeof (zc.zc_value),
518 ZDIFF_PREFIX, getpid());
519 (void) strlcpy(zc.zc_name, di->ds, sizeof (zc.zc_name));
520 zc.zc_cleanup_fd = di->cleanupfd;
521
522 if (ioctl(hdl->libzfs_fd, ZFS_IOC_TMP_SNAPSHOT, &zc) != 0) {
523 int err = errno;
524 if (err == EPERM) {
525 (void) snprintf(di->errbuf, sizeof (di->errbuf),
526 dgettext(TEXT_DOMAIN, "The diff delegated "
527 "permission is needed in order\nto create a "
528 "just-in-time snapshot for diffing\n"));
529 return (zfs_error(hdl, EZFS_DIFF, di->errbuf));
530 } else {
531 (void) snprintf(di->errbuf, sizeof (di->errbuf),
532 dgettext(TEXT_DOMAIN, "Cannot create just-in-time "
533 "snapshot of '%s'"), zc.zc_name);
534 return (zfs_standard_error(hdl, err, di->errbuf));
535 }
536 }
537
538 di->tmpsnap = zfs_strdup(hdl, zc.zc_value);
539 di->tosnap = zfs_asprintf(hdl, "%s@%s", di->ds, di->tmpsnap);
540 return (0);
541 }
542
543 static void
teardown_differ_info(differ_info_t * di)544 teardown_differ_info(differ_info_t *di)
545 {
546 free(di->ds);
547 free(di->dsmnt);
548 free(di->fromsnap);
549 free(di->frommnt);
550 free(di->tosnap);
551 free(di->tmpsnap);
552 free(di->tomnt);
553 (void) close(di->cleanupfd);
554 }
555
556 static int
get_snapshot_names(differ_info_t * di,const char * fromsnap,const char * tosnap)557 get_snapshot_names(differ_info_t *di, const char *fromsnap,
558 const char *tosnap)
559 {
560 libzfs_handle_t *hdl = di->zhp->zfs_hdl;
561 char *atptrf = NULL;
562 char *atptrt = NULL;
563 int fdslen, fsnlen;
564 int tdslen, tsnlen;
565
566 /*
567 * Can accept
568 * dataset@snap1
569 * dataset@snap1 dataset@snap2
570 * dataset@snap1 @snap2
571 * dataset@snap1 dataset
572 * @snap1 dataset@snap2
573 */
574 if (tosnap == NULL) {
575 /* only a from snapshot given, must be valid */
576 (void) snprintf(di->errbuf, sizeof (di->errbuf),
577 dgettext(TEXT_DOMAIN,
578 "Badly formed snapshot name %s"), fromsnap);
579
580 if (!zfs_validate_name(hdl, fromsnap, ZFS_TYPE_SNAPSHOT,
581 B_FALSE)) {
582 return (zfs_error(hdl, EZFS_INVALIDNAME,
583 di->errbuf));
584 }
585
586 atptrf = strchr(fromsnap, '@');
587 ASSERT(atptrf != NULL);
588 fdslen = atptrf - fromsnap;
589
590 di->fromsnap = zfs_strdup(hdl, fromsnap);
591 di->ds = zfs_strdup(hdl, fromsnap);
592 di->ds[fdslen] = '\0';
593
594 /* the to snap will be a just-in-time snap of the head */
595 return (make_temp_snapshot(di));
596 }
597
598 (void) snprintf(di->errbuf, sizeof (di->errbuf),
599 dgettext(TEXT_DOMAIN,
600 "Unable to determine which snapshots to compare"));
601
602 atptrf = strchr(fromsnap, '@');
603 atptrt = strchr(tosnap, '@');
604 fdslen = atptrf ? atptrf - fromsnap : strlen(fromsnap);
605 tdslen = atptrt ? atptrt - tosnap : strlen(tosnap);
606 fsnlen = strlen(fromsnap) - fdslen; /* includes @ sign */
607 tsnlen = strlen(tosnap) - tdslen; /* includes @ sign */
608
609 if (fsnlen <= 1 || tsnlen == 1 || (fdslen == 0 && tdslen == 0) ||
610 (fsnlen == 0 && tsnlen == 0)) {
611 return (zfs_error(hdl, EZFS_INVALIDNAME, di->errbuf));
612 } else if ((fdslen > 0 && tdslen > 0) &&
613 ((tdslen != fdslen || strncmp(fromsnap, tosnap, fdslen) != 0))) {
614 /*
615 * not the same dataset name, might be okay if
616 * tosnap is a clone of a fromsnap descendant.
617 */
618 char origin[ZFS_MAXNAMELEN];
619 zprop_source_t src;
620 zfs_handle_t *zhp;
621
622 di->ds = zfs_alloc(di->zhp->zfs_hdl, tdslen + 1);
623 (void) strncpy(di->ds, tosnap, tdslen);
624 di->ds[tdslen] = '\0';
625
626 zhp = zfs_open(hdl, di->ds, ZFS_TYPE_FILESYSTEM);
627 while (zhp != NULL) {
628 if (zfs_prop_get(zhp, ZFS_PROP_ORIGIN, origin,
629 sizeof (origin), &src, NULL, 0, B_FALSE) != 0) {
630 (void) zfs_close(zhp);
631 zhp = NULL;
632 break;
633 }
634 if (strncmp(origin, fromsnap, fsnlen) == 0)
635 break;
636
637 (void) zfs_close(zhp);
638 zhp = zfs_open(hdl, origin, ZFS_TYPE_FILESYSTEM);
639 }
640
641 if (zhp == NULL) {
642 (void) snprintf(di->errbuf, sizeof (di->errbuf),
643 dgettext(TEXT_DOMAIN,
644 "Not an earlier snapshot from the same fs"));
645 return (zfs_error(hdl, EZFS_INVALIDNAME, di->errbuf));
646 } else {
647 (void) zfs_close(zhp);
648 }
649
650 di->isclone = B_TRUE;
651 di->fromsnap = zfs_strdup(hdl, fromsnap);
652 if (tsnlen) {
653 di->tosnap = zfs_strdup(hdl, tosnap);
654 } else {
655 return (make_temp_snapshot(di));
656 }
657 } else {
658 int dslen = fdslen ? fdslen : tdslen;
659
660 di->ds = zfs_alloc(hdl, dslen + 1);
661 (void) strncpy(di->ds, fdslen ? fromsnap : tosnap, dslen);
662 di->ds[dslen] = '\0';
663
664 di->fromsnap = zfs_asprintf(hdl, "%s%s", di->ds, atptrf);
665 if (tsnlen) {
666 di->tosnap = zfs_asprintf(hdl, "%s%s", di->ds, atptrt);
667 } else {
668 return (make_temp_snapshot(di));
669 }
670 }
671 return (0);
672 }
673
674 static int
get_mountpoint(differ_info_t * di,char * dsnm,char ** mntpt)675 get_mountpoint(differ_info_t *di, char *dsnm, char **mntpt)
676 {
677 boolean_t mounted;
678
679 mounted = is_mounted(di->zhp->zfs_hdl, dsnm, mntpt);
680 if (mounted == B_FALSE) {
681 (void) snprintf(di->errbuf, sizeof (di->errbuf),
682 dgettext(TEXT_DOMAIN,
683 "Cannot diff an unmounted snapshot"));
684 return (zfs_error(di->zhp->zfs_hdl, EZFS_BADTYPE, di->errbuf));
685 }
686
687 /* Avoid a double slash at the beginning of root-mounted datasets */
688 if (**mntpt == '/' && *(*mntpt + 1) == '\0')
689 **mntpt = '\0';
690 return (0);
691 }
692
693 static int
get_mountpoints(differ_info_t * di)694 get_mountpoints(differ_info_t *di)
695 {
696 char *strptr;
697 char *frommntpt;
698
699 /*
700 * first get the mountpoint for the parent dataset
701 */
702 if (get_mountpoint(di, di->ds, &di->dsmnt) != 0)
703 return (-1);
704
705 strptr = strchr(di->tosnap, '@');
706 ASSERT3P(strptr, !=, NULL);
707 di->tomnt = zfs_asprintf(di->zhp->zfs_hdl, "%s%s%s", di->dsmnt,
708 ZDIFF_SNAPDIR, ++strptr);
709
710 strptr = strchr(di->fromsnap, '@');
711 ASSERT3P(strptr, !=, NULL);
712
713 frommntpt = di->dsmnt;
714 if (di->isclone) {
715 char *mntpt;
716 int err;
717
718 *strptr = '\0';
719 err = get_mountpoint(di, di->fromsnap, &mntpt);
720 *strptr = '@';
721 if (err != 0)
722 return (-1);
723 frommntpt = mntpt;
724 }
725
726 di->frommnt = zfs_asprintf(di->zhp->zfs_hdl, "%s%s%s", frommntpt,
727 ZDIFF_SNAPDIR, ++strptr);
728
729 if (di->isclone)
730 free(frommntpt);
731
732 return (0);
733 }
734
735 static int
setup_differ_info(zfs_handle_t * zhp,const char * fromsnap,const char * tosnap,differ_info_t * di)736 setup_differ_info(zfs_handle_t *zhp, const char *fromsnap,
737 const char *tosnap, differ_info_t *di)
738 {
739 di->zhp = zhp;
740
741 di->cleanupfd = open(ZFS_DEV, O_RDWR|O_EXCL);
742 VERIFY(di->cleanupfd >= 0);
743
744 if (get_snapshot_names(di, fromsnap, tosnap) != 0)
745 return (-1);
746
747 if (get_mountpoints(di) != 0)
748 return (-1);
749
750 if (find_shares_object(di) != 0)
751 return (-1);
752
753 return (0);
754 }
755
756 int
zfs_show_diffs(zfs_handle_t * zhp,int outfd,const char * fromsnap,const char * tosnap,int flags)757 zfs_show_diffs(zfs_handle_t *zhp, int outfd, const char *fromsnap,
758 const char *tosnap, int flags)
759 {
760 zfs_cmd_t zc = { 0 };
761 char errbuf[1024];
762 differ_info_t di = { 0 };
763 pthread_t tid;
764 int pipefd[2];
765 int iocerr;
766
767 (void) snprintf(errbuf, sizeof (errbuf),
768 dgettext(TEXT_DOMAIN, "zfs diff failed"));
769
770 if (setup_differ_info(zhp, fromsnap, tosnap, &di)) {
771 teardown_differ_info(&di);
772 return (-1);
773 }
774
775 if (pipe(pipefd)) {
776 zfs_error_aux(zhp->zfs_hdl, strerror(errno));
777 teardown_differ_info(&di);
778 return (zfs_error(zhp->zfs_hdl, EZFS_PIPEFAILED, errbuf));
779 }
780
781 di.scripted = (flags & ZFS_DIFF_PARSEABLE);
782 di.classify = (flags & ZFS_DIFF_CLASSIFY);
783 di.timestamped = (flags & ZFS_DIFF_TIMESTAMP);
784
785 di.outputfd = outfd;
786 di.datafd = pipefd[0];
787
788 if (pthread_create(&tid, NULL, differ, &di)) {
789 zfs_error_aux(zhp->zfs_hdl, strerror(errno));
790 (void) close(pipefd[0]);
791 (void) close(pipefd[1]);
792 teardown_differ_info(&di);
793 return (zfs_error(zhp->zfs_hdl,
794 EZFS_THREADCREATEFAILED, errbuf));
795 }
796
797 /* do the ioctl() */
798 (void) strlcpy(zc.zc_value, di.fromsnap, strlen(di.fromsnap) + 1);
799 (void) strlcpy(zc.zc_name, di.tosnap, strlen(di.tosnap) + 1);
800 zc.zc_cookie = pipefd[1];
801
802 iocerr = ioctl(zhp->zfs_hdl->libzfs_fd, ZFS_IOC_DIFF, &zc);
803 if (iocerr != 0) {
804 (void) snprintf(errbuf, sizeof (errbuf),
805 dgettext(TEXT_DOMAIN, "Unable to obtain diffs"));
806 if (errno == EPERM) {
807 zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
808 "\n The sys_mount privilege or diff delegated "
809 "permission is needed\n to execute the "
810 "diff ioctl"));
811 } else if (errno == EXDEV) {
812 zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
813 "\n Not an earlier snapshot from the same fs"));
814 } else if (errno != EPIPE || di.zerr == 0) {
815 zfs_error_aux(zhp->zfs_hdl, strerror(errno));
816 }
817 (void) close(pipefd[1]);
818 (void) pthread_cancel(tid);
819 (void) pthread_join(tid, NULL);
820 teardown_differ_info(&di);
821 if (di.zerr != 0 && di.zerr != EPIPE) {
822 zfs_error_aux(zhp->zfs_hdl, strerror(di.zerr));
823 return (zfs_error(zhp->zfs_hdl, EZFS_DIFF, di.errbuf));
824 } else {
825 return (zfs_error(zhp->zfs_hdl, EZFS_DIFFDATA, errbuf));
826 }
827 }
828
829 (void) close(pipefd[1]);
830 (void) pthread_join(tid, NULL);
831
832 if (di.zerr != 0) {
833 zfs_error_aux(zhp->zfs_hdl, strerror(di.zerr));
834 return (zfs_error(zhp->zfs_hdl, EZFS_DIFF, di.errbuf));
835 }
836 teardown_differ_info(&di);
837 return (0);
838 }
839