1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3 * This file and its contents are supplied under the terms of the
4 * Common Development and Distribution License ("CDDL"), version 1.0.
5 * You may only use this file in accordance with the terms of version
6 * 1.0 of the CDDL.
7 *
8 * A full copy of the text of the CDDL should have accompanied this
9 * source. A copy of the CDDL is also available via the Internet at
10 * https://opensource.org/license/CDDL-1.0.
11 */
12
13 /*
14 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
15 * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
16 * Copyright (c) 2015, 2018 by Delphix. All rights reserved.
17 * Copyright 2016 Joyent, Inc.
18 * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
19 */
20
21 /*
22 * zfs diff support
23 */
24 #include <ctype.h>
25 #include <errno.h>
26 #include <libintl.h>
27 #include <string.h>
28 #include <sys/types.h>
29 #include <sys/stat.h>
30 #include <fcntl.h>
31 #include <stddef.h>
32 #include <unistd.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <pthread.h>
36 #include <sys/zfs_ioctl.h>
37 #include <libzfs.h>
38 #include <libzutil.h>
39 #include "libzfs_impl.h"
40
41 #define ZDIFF_SNAPDIR "/.zfs/snapshot/"
42 #define ZDIFF_PREFIX "zfs-diff-%d"
43
44 #define ZDIFF_ADDED '+'
45 #define ZDIFF_MODIFIED "M"
46 #define ZDIFF_REMOVED '-'
47 #define ZDIFF_RENAMED "R"
48
49 #define ZDIFF_ADDED_COLOR ANSI_GREEN
50 #define ZDIFF_MODIFIED_COLOR ANSI_YELLOW
51 #define ZDIFF_REMOVED_COLOR ANSI_RED
52 #define ZDIFF_RENAMED_COLOR ANSI_BOLD_BLUE
53
54 /*
55 * Given a {dsname, object id}, get the object path
56 */
57 static int
get_stats_for_obj(differ_info_t * di,const char * dsname,uint64_t obj,char * pn,int maxlen,zfs_stat_t * sb)58 get_stats_for_obj(differ_info_t *di, const char *dsname, uint64_t obj,
59 char *pn, int maxlen, zfs_stat_t *sb)
60 {
61 zfs_cmd_t zc = {"\0"};
62 int error;
63
64 (void) strlcpy(zc.zc_name, dsname, sizeof (zc.zc_name));
65 zc.zc_obj = obj;
66
67 errno = 0;
68 error = zfs_ioctl(di->zhp->zfs_hdl, ZFS_IOC_OBJ_TO_STATS, &zc);
69 di->zerr = errno;
70
71 /* we can get stats even if we failed to get a path */
72 (void) memcpy(sb, &zc.zc_stat, sizeof (zfs_stat_t));
73 if (error == 0) {
74 ASSERT0(di->zerr);
75 (void) strlcpy(pn, zc.zc_value, maxlen);
76 return (0);
77 }
78
79 if (di->zerr == ESTALE) {
80 (void) snprintf(pn, maxlen, "(on_delete_queue)");
81 return (0);
82 } else if (di->zerr == EPERM) {
83 (void) snprintf(di->errbuf, sizeof (di->errbuf),
84 dgettext(TEXT_DOMAIN,
85 "The sys_config privilege or diff delegated permission "
86 "is needed\nto discover path names"));
87 return (-1);
88 } else if (di->zerr == EACCES) {
89 (void) snprintf(di->errbuf, sizeof (di->errbuf),
90 dgettext(TEXT_DOMAIN,
91 "Key must be loaded to discover path names"));
92 return (-1);
93 } else {
94 (void) snprintf(di->errbuf, sizeof (di->errbuf),
95 dgettext(TEXT_DOMAIN,
96 "Unable to determine path or stats for "
97 "object %lld in %s"), (longlong_t)obj, dsname);
98 return (-1);
99 }
100 }
101
102 /*
103 * stream_bytes
104 *
105 * Prints a file name out a character at a time. If the character is
106 * not in the range of what we consider "printable" ASCII, display it
107 * as an escaped 4-digit octal value. ASCII values less than a space
108 * are all control characters and we declare the upper end as the
109 * DELete character. This also is the last 7-bit ASCII character.
110 * We choose to treat all 8-bit ASCII as not printable for this
111 * application.
112 */
113 static void
stream_bytes(FILE * fp,const char * string)114 stream_bytes(FILE *fp, const char *string)
115 {
116 char c;
117
118 while ((c = *string++) != '\0') {
119 if (c > ' ' && c != '\\' && c < '\177') {
120 (void) fputc(c, fp);
121 } else {
122 (void) fprintf(fp, "\\%04hho", (uint8_t)c);
123 }
124 }
125 }
126
127 /*
128 * Takes the type of change (like `print_file`), outputs the appropriate color
129 */
130 static const char *
type_to_color(char type)131 type_to_color(char type)
132 {
133 if (type == '+')
134 return (ZDIFF_ADDED_COLOR);
135 else if (type == '-')
136 return (ZDIFF_REMOVED_COLOR);
137 else if (type == 'M')
138 return (ZDIFF_MODIFIED_COLOR);
139 else if (type == 'R')
140 return (ZDIFF_RENAMED_COLOR);
141 else
142 return (NULL);
143 }
144
145
146 static char
get_what(mode_t what)147 get_what(mode_t what)
148 {
149 switch (what & S_IFMT) {
150 case S_IFBLK:
151 return ('B');
152 case S_IFCHR:
153 return ('C');
154 case S_IFDIR:
155 return ('/');
156 #ifdef S_IFDOOR
157 case S_IFDOOR:
158 return ('>');
159 #endif
160 case S_IFIFO:
161 return ('|');
162 case S_IFLNK:
163 return ('@');
164 #ifdef S_IFPORT
165 case S_IFPORT:
166 return ('P');
167 #endif
168 case S_IFSOCK:
169 return ('=');
170 case S_IFREG:
171 return ('F');
172 default:
173 return ('?');
174 }
175 }
176
177 static void
print_cmn(FILE * fp,differ_info_t * di,const char * file)178 print_cmn(FILE *fp, differ_info_t *di, const char *file)
179 {
180 if (!di->no_mangle) {
181 stream_bytes(fp, di->dsmnt);
182 stream_bytes(fp, file);
183 } else {
184 (void) fputs(di->dsmnt, fp);
185 (void) fputs(file, fp);
186 }
187 }
188
189 static void
print_rename(FILE * fp,differ_info_t * di,const char * old,const char * new,zfs_stat_t * isb)190 print_rename(FILE *fp, differ_info_t *di, const char *old, const char *new,
191 zfs_stat_t *isb)
192 {
193 if (isatty(fileno(fp)))
194 color_start(ZDIFF_RENAMED_COLOR);
195 if (di->timestamped)
196 (void) fprintf(fp, "%10lld.%09lld\t",
197 (longlong_t)isb->zs_ctime[0],
198 (longlong_t)isb->zs_ctime[1]);
199 (void) fputs(ZDIFF_RENAMED "\t", fp);
200 if (di->classify)
201 (void) fprintf(fp, "%c\t", get_what(isb->zs_mode));
202 print_cmn(fp, di, old);
203 (void) fputs(di->scripted ? "\t" : " -> ", fp);
204 print_cmn(fp, di, new);
205 (void) fputc('\n', fp);
206
207 if (isatty(fileno(fp)))
208 color_end();
209 }
210
211 static void
print_link_change(FILE * fp,differ_info_t * di,int delta,const char * file,zfs_stat_t * isb)212 print_link_change(FILE *fp, differ_info_t *di, int delta, const char *file,
213 zfs_stat_t *isb)
214 {
215 if (isatty(fileno(fp)))
216 color_start(ZDIFF_MODIFIED_COLOR);
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) fputs(ZDIFF_MODIFIED "\t", fp);
223 if (di->classify)
224 (void) fprintf(fp, "%c\t", get_what(isb->zs_mode));
225 print_cmn(fp, di, file);
226 (void) fprintf(fp, "\t(%+d)\n", delta);
227 if (isatty(fileno(fp)))
228 color_end();
229 }
230
231 static void
print_file(FILE * fp,differ_info_t * di,char type,const char * file,zfs_stat_t * isb)232 print_file(FILE *fp, differ_info_t *di, char type, const char *file,
233 zfs_stat_t *isb)
234 {
235 if (isatty(fileno(fp)))
236 color_start(type_to_color(type));
237
238 if (di->timestamped)
239 (void) fprintf(fp, "%10lld.%09lld\t",
240 (longlong_t)isb->zs_ctime[0],
241 (longlong_t)isb->zs_ctime[1]);
242 (void) fprintf(fp, "%c\t", type);
243 if (di->classify)
244 (void) fprintf(fp, "%c\t", get_what(isb->zs_mode));
245 print_cmn(fp, di, file);
246 (void) fputc('\n', fp);
247
248 if (isatty(fileno(fp)))
249 color_end();
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 boolean_t already_logged = B_FALSE;
259 int fobjerr, tobjerr;
260 int change;
261
262 if (dobj == di->shares)
263 return (0);
264
265 /*
266 * Check the from and to snapshots for info on the object. If
267 * we get ENOENT, then the object just didn't exist in that
268 * snapshot. If we get ENOTSUP, then we tried to get
269 * info on a non-ZPL object, which we don't care about anyway.
270 * For any other error we print a warning which includes the
271 * errno and continue.
272 */
273
274 fobjerr = get_stats_for_obj(di, di->fromsnap, dobj, fobjname,
275 MAXPATHLEN, &fsb);
276 if (fobjerr && di->zerr != ENOTSUP && di->zerr != ENOENT) {
277 zfs_error_aux(di->zhp->zfs_hdl, "%s", zfs_strerror(di->zerr));
278 zfs_error(di->zhp->zfs_hdl, di->zerr, di->errbuf);
279 /*
280 * Let's not print an error for the same object more than
281 * once if it happens in both snapshots
282 */
283 already_logged = B_TRUE;
284 }
285
286 tobjerr = get_stats_for_obj(di, di->tosnap, dobj, tobjname,
287 MAXPATHLEN, &tsb);
288
289 if (tobjerr && di->zerr != ENOTSUP && di->zerr != ENOENT) {
290 if (!already_logged) {
291 zfs_error_aux(di->zhp->zfs_hdl,
292 "%s", zfs_strerror(di->zerr));
293 zfs_error(di->zhp->zfs_hdl, di->zerr, di->errbuf);
294 }
295 }
296 /*
297 * Unallocated object sharing the same meta dnode block
298 */
299 if (fobjerr && tobjerr) {
300 di->zerr = 0;
301 return (0);
302 }
303
304 di->zerr = 0; /* negate get_stats_for_obj() from side that failed */
305 fmode = fsb.zs_mode & S_IFMT;
306 tmode = tsb.zs_mode & S_IFMT;
307 if (fmode == S_IFDIR || tmode == S_IFDIR || fsb.zs_links == 0 ||
308 tsb.zs_links == 0)
309 change = 0;
310 else
311 change = tsb.zs_links - fsb.zs_links;
312
313 if (fobjerr) {
314 if (change) {
315 print_link_change(fp, di, change, tobjname, &tsb);
316 return (0);
317 }
318 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
319 return (0);
320 } else if (tobjerr) {
321 if (change) {
322 print_link_change(fp, di, change, fobjname, &fsb);
323 return (0);
324 }
325 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
326 return (0);
327 }
328
329 if (fmode != tmode && fsb.zs_gen == tsb.zs_gen)
330 tsb.zs_gen++; /* Force a generational difference */
331
332 /* Simple modification or no change */
333 if (fsb.zs_gen == tsb.zs_gen) {
334 /* No apparent changes. Could we assert !this? */
335 if (fsb.zs_ctime[0] == tsb.zs_ctime[0] &&
336 fsb.zs_ctime[1] == tsb.zs_ctime[1])
337 return (0);
338 if (change) {
339 print_link_change(fp, di, change,
340 change > 0 ? fobjname : tobjname, &tsb);
341 } else if (strcmp(fobjname, tobjname) == 0) {
342 print_file(fp, di, *ZDIFF_MODIFIED, fobjname, &tsb);
343 } else {
344 print_rename(fp, di, fobjname, tobjname, &tsb);
345 }
346 return (0);
347 } else {
348 /* file re-created or object re-used */
349 print_file(fp, di, ZDIFF_REMOVED, fobjname, &fsb);
350 print_file(fp, di, ZDIFF_ADDED, tobjname, &tsb);
351 return (0);
352 }
353 }
354
355 static int
write_inuse_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)356 write_inuse_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
357 {
358 uint64_t o;
359 int err;
360
361 for (o = dr->ddr_first; o <= dr->ddr_last; o++) {
362 if ((err = write_inuse_diffs_one(fp, di, o)) != 0)
363 return (err);
364 }
365 return (0);
366 }
367
368 static int
describe_free(FILE * fp,differ_info_t * di,uint64_t object,char * namebuf,int maxlen)369 describe_free(FILE *fp, differ_info_t *di, uint64_t object, char *namebuf,
370 int maxlen)
371 {
372 struct zfs_stat sb;
373
374 (void) get_stats_for_obj(di, di->fromsnap, object, namebuf,
375 maxlen, &sb);
376
377 /* Don't print if in the delete queue on from side */
378 if (di->zerr == ESTALE || di->zerr == ENOENT) {
379 di->zerr = 0;
380 return (0);
381 }
382
383 print_file(fp, di, ZDIFF_REMOVED, namebuf, &sb);
384 return (0);
385 }
386
387 static int
write_free_diffs(FILE * fp,differ_info_t * di,dmu_diff_record_t * dr)388 write_free_diffs(FILE *fp, differ_info_t *di, dmu_diff_record_t *dr)
389 {
390 zfs_cmd_t zc = {"\0"};
391 libzfs_handle_t *lhdl = di->zhp->zfs_hdl;
392 char fobjname[MAXPATHLEN];
393
394 (void) strlcpy(zc.zc_name, di->fromsnap, sizeof (zc.zc_name));
395 zc.zc_obj = dr->ddr_first - 1;
396
397 ASSERT0(di->zerr);
398
399 while (zc.zc_obj < dr->ddr_last) {
400 int err;
401
402 err = zfs_ioctl(lhdl, ZFS_IOC_NEXT_OBJ, &zc);
403 if (err == 0) {
404 if (zc.zc_obj == di->shares) {
405 zc.zc_obj++;
406 continue;
407 }
408 if (zc.zc_obj > dr->ddr_last) {
409 break;
410 }
411 (void) describe_free(fp, di, zc.zc_obj, fobjname,
412 MAXPATHLEN);
413 } else if (errno == ESRCH) {
414 break;
415 } else {
416 (void) snprintf(di->errbuf, sizeof (di->errbuf),
417 dgettext(TEXT_DOMAIN,
418 "next allocated object (> %lld) find failure"),
419 (longlong_t)zc.zc_obj);
420 di->zerr = errno;
421 break;
422 }
423 }
424 if (di->zerr)
425 return (-1);
426 return (0);
427 }
428
429 static void *
differ(void * arg)430 differ(void *arg)
431 {
432 differ_info_t *di = arg;
433 dmu_diff_record_t dr;
434 FILE *ofp;
435 int err = 0;
436
437 if ((ofp = fdopen(di->outputfd, "w")) == NULL) {
438 di->zerr = errno;
439 strlcpy(di->errbuf, zfs_strerror(errno), sizeof (di->errbuf));
440 (void) close(di->datafd);
441 return ((void *)-1);
442 }
443
444 for (;;) {
445 char *cp = (char *)&dr;
446 int len = sizeof (dr);
447 int rv;
448
449 do {
450 rv = read(di->datafd, cp, len);
451 cp += rv;
452 len -= rv;
453 } while (len > 0 && rv > 0);
454
455 if (rv < 0 || (rv == 0 && len != sizeof (dr))) {
456 di->zerr = EPIPE;
457 break;
458 } else if (rv == 0) {
459 /* end of file at a natural breaking point */
460 break;
461 }
462
463 switch (dr.ddr_type) {
464 case DDR_FREE:
465 err = write_free_diffs(ofp, di, &dr);
466 break;
467 case DDR_INUSE:
468 err = write_inuse_diffs(ofp, di, &dr);
469 break;
470 default:
471 di->zerr = EPIPE;
472 break;
473 }
474
475 if (err || di->zerr)
476 break;
477 }
478
479 (void) fclose(ofp);
480 (void) close(di->datafd);
481 if (err)
482 return ((void *)-1);
483 if (di->zerr) {
484 ASSERT(di->zerr == EPIPE);
485 (void) snprintf(di->errbuf, sizeof (di->errbuf),
486 dgettext(TEXT_DOMAIN,
487 "Internal error: bad data from diff IOCTL"));
488 return ((void *)-1);
489 }
490 return ((void *)0);
491 }
492
493 static int
make_temp_snapshot(differ_info_t * di)494 make_temp_snapshot(differ_info_t *di)
495 {
496 libzfs_handle_t *hdl = di->zhp->zfs_hdl;
497 zfs_cmd_t zc = {"\0"};
498
499 (void) snprintf(zc.zc_value, sizeof (zc.zc_value),
500 ZDIFF_PREFIX, getpid());
501 (void) strlcpy(zc.zc_name, di->ds, sizeof (zc.zc_name));
502 zc.zc_cleanup_fd = di->cleanupfd;
503
504 if (zfs_ioctl(hdl, ZFS_IOC_TMP_SNAPSHOT, &zc) != 0) {
505 int err = errno;
506 if (err == EPERM) {
507 (void) snprintf(di->errbuf, sizeof (di->errbuf),
508 dgettext(TEXT_DOMAIN, "The diff delegated "
509 "permission is needed in order\nto create a "
510 "just-in-time snapshot for diffing\n"));
511 return (zfs_error(hdl, EZFS_DIFF, di->errbuf));
512 } else {
513 (void) snprintf(di->errbuf, sizeof (di->errbuf),
514 dgettext(TEXT_DOMAIN, "Cannot create just-in-time "
515 "snapshot of '%s'"), zc.zc_name);
516 return (zfs_standard_error(hdl, err, di->errbuf));
517 }
518 }
519
520 di->tmpsnap = zfs_strdup(hdl, zc.zc_value);
521 di->tosnap = zfs_asprintf(hdl, "%s@%s", di->ds, di->tmpsnap);
522 return (0);
523 }
524
525 static void
teardown_differ_info(differ_info_t * di)526 teardown_differ_info(differ_info_t *di)
527 {
528 free(di->ds);
529 free(di->dsmnt);
530 free(di->fromsnap);
531 free(di->frommnt);
532 free(di->tosnap);
533 free(di->tmpsnap);
534 free(di->tomnt);
535 (void) close(di->cleanupfd);
536 }
537
538 static int
get_snapshot_names(differ_info_t * di,const char * fromsnap,const char * tosnap)539 get_snapshot_names(differ_info_t *di, const char *fromsnap,
540 const char *tosnap)
541 {
542 libzfs_handle_t *hdl = di->zhp->zfs_hdl;
543 const char *atptrf = NULL;
544 const char *atptrt = NULL;
545 int fdslen, fsnlen;
546 int tdslen, tsnlen;
547
548 /*
549 * Can accept
550 * fdslen fsnlen tdslen tsnlen
551 * dataset@snap1
552 * 0. dataset@snap1 dataset@snap2 >0 >1 >0 >1
553 * 1. dataset@snap1 @snap2 >0 >1 ==0 >1
554 * 2. dataset@snap1 dataset >0 >1 >0 ==0
555 * 3. @snap1 dataset@snap2 ==0 >1 >0 >1
556 * 4. @snap1 dataset ==0 >1 >0 ==0
557 */
558 if (tosnap == NULL) {
559 /* only a from snapshot given, must be valid */
560 (void) snprintf(di->errbuf, sizeof (di->errbuf),
561 dgettext(TEXT_DOMAIN,
562 "Badly formed snapshot name %s"), fromsnap);
563
564 if (!zfs_validate_name(hdl, fromsnap, ZFS_TYPE_SNAPSHOT,
565 B_FALSE)) {
566 return (zfs_error(hdl, EZFS_INVALIDNAME,
567 di->errbuf));
568 }
569
570 atptrf = strchr(fromsnap, '@');
571 ASSERT(atptrf != NULL);
572 fdslen = atptrf - fromsnap;
573
574 di->fromsnap = zfs_strdup(hdl, fromsnap);
575 di->ds = zfs_strdup(hdl, fromsnap);
576 di->ds[fdslen] = '\0';
577
578 /* the to snap will be a just-in-time snap of the head */
579 return (make_temp_snapshot(di));
580 }
581
582 (void) snprintf(di->errbuf, sizeof (di->errbuf),
583 dgettext(TEXT_DOMAIN,
584 "Unable to determine which snapshots to compare"));
585
586 atptrf = strchr(fromsnap, '@');
587 atptrt = strchr(tosnap, '@');
588 fdslen = atptrf ? atptrf - fromsnap : strlen(fromsnap);
589 tdslen = atptrt ? atptrt - tosnap : strlen(tosnap);
590 fsnlen = strlen(fromsnap) - fdslen; /* includes @ sign */
591 tsnlen = strlen(tosnap) - tdslen; /* includes @ sign */
592
593 if (fsnlen <= 1 || tsnlen == 1 || (fdslen == 0 && tdslen == 0)) {
594 return (zfs_error(hdl, EZFS_INVALIDNAME, di->errbuf));
595 } else if ((fdslen > 0 && tdslen > 0) &&
596 ((tdslen != fdslen || strncmp(fromsnap, tosnap, fdslen) != 0))) {
597 /*
598 * not the same dataset name, might be okay if
599 * tosnap is a clone of a fromsnap descendant.
600 */
601 char origin[ZFS_MAX_DATASET_NAME_LEN];
602 zprop_source_t src;
603 zfs_handle_t *zhp;
604
605 di->ds = zfs_alloc(di->zhp->zfs_hdl, tdslen + 1);
606 (void) strlcpy(di->ds, tosnap, tdslen + 1);
607
608 zhp = zfs_open(hdl, di->ds, ZFS_TYPE_FILESYSTEM);
609 while (zhp != NULL) {
610 if (zfs_prop_get(zhp, ZFS_PROP_ORIGIN, origin,
611 sizeof (origin), &src, NULL, 0, B_FALSE) != 0) {
612 (void) zfs_close(zhp);
613 zhp = NULL;
614 break;
615 }
616 if (strncmp(origin, fromsnap, fsnlen) == 0)
617 break;
618
619 (void) zfs_close(zhp);
620 zhp = zfs_open(hdl, origin, ZFS_TYPE_FILESYSTEM);
621 }
622
623 if (zhp == NULL) {
624 (void) snprintf(di->errbuf, sizeof (di->errbuf),
625 dgettext(TEXT_DOMAIN,
626 "Not an earlier snapshot from the same fs"));
627 return (zfs_error(hdl, EZFS_INVALIDNAME, di->errbuf));
628 } else {
629 (void) zfs_close(zhp);
630 }
631
632 di->isclone = B_TRUE;
633 di->fromsnap = zfs_strdup(hdl, fromsnap);
634 if (tsnlen)
635 di->tosnap = zfs_strdup(hdl, tosnap);
636 else
637 return (make_temp_snapshot(di));
638 } else {
639 int dslen = fdslen ? fdslen : tdslen;
640
641 di->ds = zfs_alloc(hdl, dslen + 1);
642 (void) strlcpy(di->ds, fdslen ? fromsnap : tosnap, dslen + 1);
643
644 di->fromsnap = zfs_asprintf(hdl, "%s%s", di->ds, atptrf);
645 if (tsnlen) {
646 di->tosnap = zfs_asprintf(hdl, "%s%s", di->ds, atptrt);
647 } else {
648 return (make_temp_snapshot(di));
649 }
650 }
651 return (0);
652 }
653
654 static int
get_mountpoint(differ_info_t * di,char * dsnm,char ** mntpt)655 get_mountpoint(differ_info_t *di, char *dsnm, char **mntpt)
656 {
657 boolean_t mounted;
658
659 mounted = is_mounted(di->zhp->zfs_hdl, dsnm, mntpt);
660 if (mounted == B_FALSE) {
661 (void) snprintf(di->errbuf, sizeof (di->errbuf),
662 dgettext(TEXT_DOMAIN,
663 "Cannot diff an unmounted snapshot"));
664 return (zfs_error(di->zhp->zfs_hdl, EZFS_BADTYPE, di->errbuf));
665 }
666
667 /* Avoid a double slash at the beginning of root-mounted datasets */
668 if (**mntpt == '/' && *(*mntpt + 1) == '\0')
669 **mntpt = '\0';
670 return (0);
671 }
672
673 static int
get_mountpoints(differ_info_t * di)674 get_mountpoints(differ_info_t *di)
675 {
676 char *strptr;
677 char *frommntpt;
678
679 /*
680 * first get the mountpoint for the parent dataset
681 */
682 if (get_mountpoint(di, di->ds, &di->dsmnt) != 0)
683 return (-1);
684
685 strptr = strchr(di->tosnap, '@');
686 ASSERT3P(strptr, !=, NULL);
687 di->tomnt = zfs_asprintf(di->zhp->zfs_hdl, "%s%s%s", di->dsmnt,
688 ZDIFF_SNAPDIR, ++strptr);
689
690 strptr = strchr(di->fromsnap, '@');
691 ASSERT3P(strptr, !=, NULL);
692
693 frommntpt = di->dsmnt;
694 if (di->isclone) {
695 char *mntpt;
696 int err;
697
698 *strptr = '\0';
699 err = get_mountpoint(di, di->fromsnap, &mntpt);
700 *strptr = '@';
701 if (err != 0)
702 return (-1);
703 frommntpt = mntpt;
704 }
705
706 di->frommnt = zfs_asprintf(di->zhp->zfs_hdl, "%s%s%s", frommntpt,
707 ZDIFF_SNAPDIR, ++strptr);
708
709 if (di->isclone)
710 free(frommntpt);
711
712 return (0);
713 }
714
715 static int
setup_differ_info(zfs_handle_t * zhp,const char * fromsnap,const char * tosnap,differ_info_t * di)716 setup_differ_info(zfs_handle_t *zhp, const char *fromsnap,
717 const char *tosnap, differ_info_t *di)
718 {
719 di->zhp = zhp;
720
721 di->cleanupfd = open(ZFS_DEV, O_RDWR | O_CLOEXEC);
722 VERIFY(di->cleanupfd >= 0);
723
724 if (get_snapshot_names(di, fromsnap, tosnap) != 0)
725 return (-1);
726
727 if (get_mountpoints(di) != 0)
728 return (-1);
729
730 if (find_shares_object(di) != 0)
731 return (-1);
732
733 return (0);
734 }
735
736 int
zfs_show_diffs(zfs_handle_t * zhp,int outfd,const char * fromsnap,const char * tosnap,int flags)737 zfs_show_diffs(zfs_handle_t *zhp, int outfd, const char *fromsnap,
738 const char *tosnap, int flags)
739 {
740 zfs_cmd_t zc = {"\0"};
741 char errbuf[ERRBUFLEN];
742 differ_info_t di = { 0 };
743 pthread_t tid;
744 int pipefd[2];
745 int iocerr;
746
747 (void) snprintf(errbuf, sizeof (errbuf),
748 dgettext(TEXT_DOMAIN, "zfs diff failed"));
749
750 if (setup_differ_info(zhp, fromsnap, tosnap, &di)) {
751 teardown_differ_info(&di);
752 return (-1);
753 }
754
755 if (pipe2(pipefd, O_CLOEXEC)) {
756 zfs_error_aux(zhp->zfs_hdl, "%s", zfs_strerror(errno));
757 teardown_differ_info(&di);
758 return (zfs_error(zhp->zfs_hdl, EZFS_PIPEFAILED, errbuf));
759 }
760
761 di.scripted = (flags & ZFS_DIFF_PARSEABLE);
762 di.classify = (flags & ZFS_DIFF_CLASSIFY);
763 di.timestamped = (flags & ZFS_DIFF_TIMESTAMP);
764 di.no_mangle = (flags & ZFS_DIFF_NO_MANGLE);
765
766 di.outputfd = outfd;
767 di.datafd = pipefd[0];
768
769 if (pthread_create(&tid, NULL, differ, &di)) {
770 zfs_error_aux(zhp->zfs_hdl, "%s", zfs_strerror(errno));
771 (void) close(pipefd[0]);
772 (void) close(pipefd[1]);
773 teardown_differ_info(&di);
774 return (zfs_error(zhp->zfs_hdl,
775 EZFS_THREADCREATEFAILED, errbuf));
776 }
777
778 /* do the ioctl() */
779 (void) strlcpy(zc.zc_value, di.fromsnap, strlen(di.fromsnap) + 1);
780 (void) strlcpy(zc.zc_name, di.tosnap, strlen(di.tosnap) + 1);
781 zc.zc_cookie = pipefd[1];
782
783 iocerr = zfs_ioctl(zhp->zfs_hdl, ZFS_IOC_DIFF, &zc);
784 if (iocerr != 0) {
785 (void) snprintf(errbuf, sizeof (errbuf),
786 dgettext(TEXT_DOMAIN, "Unable to obtain diffs"));
787 if (errno == EPERM) {
788 zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
789 "\n The sys_mount privilege or diff delegated "
790 "permission is needed\n to execute the "
791 "diff ioctl"));
792 } else if (errno == EXDEV) {
793 zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
794 "\n Not an earlier snapshot from the same fs"));
795 } else if (errno != EPIPE || di.zerr == 0) {
796 zfs_error_aux(zhp->zfs_hdl, "%s", zfs_strerror(errno));
797 }
798 (void) close(pipefd[1]);
799 (void) pthread_cancel(tid);
800 (void) pthread_join(tid, NULL);
801 teardown_differ_info(&di);
802 if (di.zerr != 0 && di.zerr != EPIPE) {
803 zfs_error_aux(zhp->zfs_hdl, "%s",
804 zfs_strerror(di.zerr));
805 return (zfs_error(zhp->zfs_hdl, EZFS_DIFF, di.errbuf));
806 } else {
807 return (zfs_error(zhp->zfs_hdl, EZFS_DIFFDATA, errbuf));
808 }
809 }
810
811 (void) close(pipefd[1]);
812 (void) pthread_join(tid, NULL);
813
814 teardown_differ_info(&di);
815 if (di.zerr != 0) {
816 zfs_error_aux(zhp->zfs_hdl, "%s", zfs_strerror(di.zerr));
817 return (zfs_error(zhp->zfs_hdl, EZFS_DIFF, di.errbuf));
818 }
819 return (0);
820 }
821