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10ee5932 KZ |
1 | /* |
2 | * Copyright (C) 2011 Karel Zak <kzak@redhat.com> | |
3 | * | |
4 | * -- based on mount/losetup.c | |
5 | * | |
6 | * Simple library for work with loop devices. | |
7 | * | |
8 | * - requires kernel 2.6.x | |
9 | * - reads info from /sys/block/loop<N>/loop/<attr> (new kernels) | |
10 | * - reads info by ioctl | |
11 | * - supports *unlimited* number of loop devices | |
12 | * - supports /dev/loop<N> as well as /dev/loop/<N> | |
13 | * - minimize overhead (fd, loopinfo, ... are shared for all operations) | |
14 | * - setup (associate device and backing file) | |
15 | * - delete (dis-associate file) | |
16 | * - old LOOP_{SET,GET}_STATUS (32bit) ioctls are unsupported | |
17 | * - extendible | |
18 | */ | |
19 | #include <stdio.h> | |
20 | #include <stdint.h> | |
21 | #include <string.h> | |
22 | #include <ctype.h> | |
23 | #include <fcntl.h> | |
10ee5932 KZ |
24 | #include <stdlib.h> |
25 | #include <unistd.h> | |
26 | #include <sys/ioctl.h> | |
27 | #include <sys/stat.h> | |
28 | #include <sys/mman.h> | |
29 | #include <sys/sysmacros.h> | |
30 | #include <inttypes.h> | |
31 | #include <dirent.h> | |
32 | #include <linux/posix_types.h> | |
33 | ||
34 | #include "linux_version.h" | |
35 | #include "c.h" | |
36 | #include "sysfs.h" | |
37 | #include "pathnames.h" | |
38 | #include "loopdev.h" | |
39 | #include "canonicalize.h" | |
40 | ||
41 | #define loopcxt_ioctl_enabled(_lc) (!((_lc)->flags & LOOPDEV_FL_NOIOCTL)) | |
42 | ||
43 | /* | |
44 | * @lc: context | |
45 | * @device: device name, absolute device path or NULL to reset the current setting | |
46 | * | |
47 | * Sets device, absolute paths (e.g. "/dev/loop<N>") are unchanged, device | |
48 | * names ("loop<N>") are converted to the path (/dev/loop<N> or to | |
49 | * /dev/loop/<N>) | |
50 | * | |
51 | * Returns: <0 on error, 0 on success | |
52 | */ | |
53 | int loopcxt_set_device(struct loopdev_cxt *lc, const char *device) | |
54 | { | |
55 | if (!lc) | |
56 | return -EINVAL; | |
57 | ||
58 | if (lc->fd >= 0) | |
59 | close(lc->fd); | |
60 | lc->fd = -1; | |
fd7f0718 | 61 | lc->mode = 0; |
10ee5932 KZ |
62 | lc->has_info = 0; |
63 | *lc->device = '\0'; | |
fd7f0718 | 64 | memset(&lc->info, 0, sizeof(lc->info)); |
10ee5932 KZ |
65 | |
66 | /* set new */ | |
67 | if (device) { | |
68 | if (*device != '/') { | |
69 | const char *dir = _PATH_DEV; | |
70 | ||
71 | /* compose device name for /dev/loop<n> or /dev/loop/<n> */ | |
72 | if (lc->flags & LOOPDEV_FL_DEVSUBDIR) { | |
73 | if (strlen(device) < 5) | |
74 | return -1; | |
75 | device += 4; | |
76 | dir = _PATH_DEV_LOOP "/"; /* _PATH_DEV uses tailing slash */ | |
77 | } | |
78 | snprintf(lc->device, sizeof(lc->device), "%s%s", | |
79 | dir, device); | |
80 | } else { | |
81 | strncpy(lc->device, device, sizeof(lc->device)); | |
82 | lc->device[sizeof(lc->device) - 1] = '\0'; | |
83 | } | |
84 | } | |
85 | ||
86 | sysfs_deinit(&lc->sysfs); | |
87 | return 0; | |
88 | } | |
89 | ||
90 | /* | |
91 | * @lc: context | |
92 | * @flags: LOOPDEV_FL_* flags | |
93 | * | |
94 | * Initilize loop handler. | |
95 | * | |
fd7f0718 KZ |
96 | * We have two sets of the flags: |
97 | * | |
98 | * * LOOPDEV_FL_* flags control loopcxt_* API behavior | |
99 | * | |
100 | * * LO_FLAGS_* are kernel flags used for LOOP_{SET,GET}_STAT64 ioctls | |
101 | * | |
102 | * Note about LOOPDEV_FL_{RDONLY,RDWR} flags. These flags are used for open(2) | |
103 | * syscall to open loop device. By default is the device open read-only. | |
104 | * | |
105 | * The expection is loopcxt_setup_device(), where the device is open read-write | |
106 | * if LO_FLAGS_READ_ONLY flags is not set (see loopcxt_set_flags()). | |
107 | * | |
10ee5932 KZ |
108 | * Returns: <0 on error, 0 on success. |
109 | */ | |
110 | int loopcxt_init(struct loopdev_cxt *lc, int flags) | |
111 | { | |
112 | if (!lc) | |
113 | return -EINVAL; | |
114 | ||
115 | memset(lc, 0, sizeof(*lc)); | |
116 | lc->flags = flags; | |
117 | loopcxt_set_device(lc, NULL); | |
118 | ||
119 | if (!(lc->flags && LOOPDEV_FL_NOSYSFS) && | |
120 | get_linux_version() >= KERNEL_VERSION(2,6,37)) | |
121 | /* | |
122 | * Use only sysfs for basic information about loop devices | |
123 | */ | |
124 | lc->flags |= LOOPDEV_FL_NOIOCTL; | |
125 | ||
126 | return 0; | |
127 | } | |
128 | ||
129 | /* | |
130 | * @lc: context | |
131 | * | |
132 | * Deinitialize loop context | |
133 | */ | |
134 | void loopcxt_deinit(struct loopdev_cxt *lc) | |
135 | { | |
136 | if (!lc) | |
137 | return; | |
138 | ||
139 | free(lc->filename); | |
140 | lc->filename = NULL; | |
141 | ||
142 | loopcxt_set_device(lc, NULL); | |
143 | loopcxt_deinit_iterator(lc); | |
144 | } | |
145 | ||
146 | /* | |
147 | * @lc: context | |
148 | * | |
149 | * Returns newly allocated device path. | |
150 | */ | |
151 | char *loopcxt_strdup_device(struct loopdev_cxt *lc) | |
152 | { | |
153 | if (!lc || !*lc->device) | |
154 | return NULL; | |
155 | return strdup(lc->device); | |
156 | } | |
157 | ||
158 | /* | |
159 | * @lc: context | |
160 | * | |
161 | * Returns pointer device name in the @lc struct. | |
162 | */ | |
163 | const char *loopcxt_get_device(struct loopdev_cxt *lc) | |
164 | { | |
165 | return lc ? lc->device : NULL; | |
166 | } | |
167 | ||
168 | /* | |
169 | * @lc: context | |
170 | * | |
171 | * Returns pointer to the sysfs context (see lib/sysfs.c) | |
172 | */ | |
173 | struct sysfs_cxt *loopcxt_get_sysfs(struct loopdev_cxt *lc) | |
174 | { | |
175 | if (!lc || !*lc->device || (lc->flags & LOOPDEV_FL_NOSYSFS)) | |
176 | return NULL; | |
177 | ||
178 | if (!lc->sysfs.devno) { | |
179 | dev_t devno = sysfs_devname_to_devno(lc->device, NULL); | |
180 | if (!devno) | |
181 | return NULL; | |
182 | ||
183 | if (sysfs_init(&lc->sysfs, devno, NULL)) | |
184 | return NULL; | |
185 | } | |
186 | return &lc->sysfs; | |
187 | } | |
188 | ||
189 | /* | |
190 | * @lc: context | |
191 | * | |
192 | * Returns: file descriptor to the open loop device or <0 on error. The mode | |
193 | * depends on LOOPDEV_FL_{RDWR,RDONLY} context flags. Default is | |
194 | * read-only. | |
195 | */ | |
196 | int loopcxt_get_fd(struct loopdev_cxt *lc) | |
197 | { | |
198 | if (!lc || !*lc->device) | |
fd7f0718 | 199 | return -EINVAL; |
10ee5932 | 200 | |
fd7f0718 KZ |
201 | if (lc->fd < 0) { |
202 | lc->mode = lc->flags & LOOPDEV_FL_RDWR ? O_RDWR : O_RDONLY; | |
203 | lc->fd = open(lc->device, lc->mode); | |
204 | } | |
10ee5932 KZ |
205 | return lc->fd; |
206 | } | |
207 | ||
fd7f0718 KZ |
208 | int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, int mode) |
209 | { | |
210 | if (!lc) | |
211 | return -EINVAL; | |
212 | ||
213 | lc->fd = fd; | |
214 | lc->mode = mode; | |
215 | return 0; | |
216 | } | |
217 | ||
10ee5932 KZ |
218 | /* |
219 | * @lc: context | |
220 | * @flags: LOOPITER_FL_* flags | |
221 | * | |
222 | * Iterator allows to scan list of the free or used loop devices. | |
223 | * | |
224 | * Returns: <0 on error, 0 on success | |
225 | */ | |
226 | int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags) | |
227 | { | |
228 | struct loopdev_iter *iter; | |
229 | struct stat st; | |
230 | ||
231 | if (!lc) | |
232 | return -EINVAL; | |
233 | ||
234 | iter = &lc->iter; | |
235 | ||
236 | /* always zeroize | |
237 | */ | |
238 | memset(iter, 0, sizeof(*iter)); | |
239 | iter->ncur = -1; | |
240 | iter->flags = flags; | |
241 | iter->default_check = 1; | |
242 | ||
243 | if (!lc->extra_check) { | |
244 | /* | |
245 | * Check for /dev/loop/<N> subdirectory | |
246 | */ | |
247 | if (!(lc->flags && LOOPDEV_FL_DEVSUBDIR) && | |
248 | stat(_PATH_DEV_LOOP, &st) == 0 && S_ISDIR(st.st_mode)) | |
249 | lc->flags |= LOOPDEV_FL_DEVSUBDIR; | |
250 | ||
251 | lc->extra_check = 1; | |
252 | } | |
253 | return 0; | |
254 | } | |
255 | ||
256 | /* | |
257 | * @lc: context | |
258 | * | |
259 | * Returns: <0 on error, 0 on success | |
260 | */ | |
261 | int loopcxt_deinit_iterator(struct loopdev_cxt *lc) | |
262 | { | |
263 | struct loopdev_iter *iter = &lc->iter; | |
264 | ||
265 | if (!lc) | |
266 | return -EINVAL; | |
267 | ||
268 | iter = &lc->iter; | |
269 | ||
270 | free(iter->minors); | |
271 | if (iter->proc) | |
272 | fclose(iter->proc); | |
273 | iter->minors = NULL; | |
274 | iter->proc = NULL; | |
275 | iter->done = 1; | |
276 | return 0; | |
277 | } | |
278 | ||
279 | /* | |
280 | * Same as loopcxt_set_device, but also checks if the device is | |
281 | * associeted with any file. | |
282 | * | |
283 | * Returns: <0 on error, 0 on success, 1 device does not match with | |
284 | * LOOPITER_FL_{USED,FREE} flags. | |
285 | */ | |
286 | static int loopiter_set_device(struct loopdev_cxt *lc, const char *device) | |
287 | { | |
288 | int rc = loopcxt_set_device(lc, device); | |
289 | int used; | |
290 | ||
291 | if (rc) | |
292 | return rc; | |
293 | ||
294 | if (!(lc->iter.flags & LOOPITER_FL_USED) && | |
295 | !(lc->iter.flags & LOOPITER_FL_FREE)) | |
296 | return 0; /* caller does not care about device status */ | |
297 | ||
298 | used = loopcxt_get_offset(lc, NULL) == 0; | |
299 | ||
300 | if ((lc->iter.flags & LOOPITER_FL_USED) && used) | |
301 | return 0; | |
302 | ||
303 | if ((lc->iter.flags & LOOPITER_FL_FREE) && !used) | |
304 | return 0; | |
305 | ||
306 | loopcxt_set_device(lc, NULL); | |
307 | return 1; | |
308 | } | |
309 | ||
310 | static int cmpnum(const void *p1, const void *p2) | |
311 | { | |
33487796 KZ |
312 | return (((* (int *) p1) > (* (int *) p2)) - |
313 | ((* (int *) p1) < (* (int *) p2))); | |
10ee5932 KZ |
314 | } |
315 | ||
316 | /* | |
317 | * The classic scandir() is more expensive and less portable. | |
318 | * We needn't full loop device names -- loop numbers (loop<N>) | |
319 | * are enough. | |
320 | */ | |
321 | static int loop_scandir(const char *dirname, int **ary, int hasprefix) | |
322 | { | |
323 | DIR *dir; | |
324 | struct dirent *d; | |
325 | unsigned int n, count = 0, arylen = 0; | |
326 | ||
327 | if (!dirname || !ary) | |
328 | return 0; | |
329 | dir = opendir(dirname); | |
330 | if (!dir) | |
331 | return 0; | |
332 | ||
333 | free(*ary); | |
334 | *ary = NULL; | |
335 | ||
336 | while((d = readdir(dir))) { | |
337 | #ifdef _DIRENT_HAVE_D_TYPE | |
338 | if (d->d_type != DT_BLK && d->d_type != DT_UNKNOWN && | |
339 | d->d_type != DT_LNK) | |
340 | continue; | |
341 | #endif | |
342 | if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, "..")) | |
343 | continue; | |
344 | ||
345 | if (hasprefix) { | |
346 | /* /dev/loop<N> */ | |
347 | if (sscanf(d->d_name, "loop%u", &n) != 1) | |
348 | continue; | |
349 | } else { | |
350 | /* /dev/loop/<N> */ | |
351 | char *end = NULL; | |
352 | ||
353 | n = strtol(d->d_name, &end, 10); | |
354 | if (d->d_name == end || (end && *end) || errno) | |
355 | continue; | |
356 | } | |
357 | if (n < LOOPDEV_DEFAULT_NNODES) | |
358 | continue; /* ignore loop<0..7> */ | |
359 | ||
360 | if (count + 1 > arylen) { | |
361 | int *tmp; | |
362 | ||
363 | arylen += 1; | |
364 | ||
365 | tmp = realloc(*ary, arylen * sizeof(int)); | |
366 | if (!tmp) { | |
367 | free(*ary); | |
368 | return -1; | |
369 | } | |
370 | *ary = tmp; | |
371 | } | |
372 | (*ary)[count++] = n; | |
373 | } | |
374 | if (count) | |
375 | qsort(*ary, count, sizeof(int), cmpnum); | |
376 | ||
377 | closedir(dir); | |
378 | return count; | |
379 | } | |
380 | ||
381 | /* | |
382 | * @lc: context, has to initialized by loopcxt_init_iterator() | |
383 | * | |
384 | * Returns: 0 on success, -1 on error, 1 at the end of scanning. The details | |
385 | * about the current loop device are available by | |
386 | * loopcxt_get_{fd,backing_file,device,offset, ...} functions. | |
387 | */ | |
388 | int loopcxt_next(struct loopdev_cxt *lc) | |
389 | { | |
390 | struct loopdev_iter *iter; | |
391 | ||
392 | if (!lc) | |
393 | return -EINVAL; | |
394 | iter = &lc->iter; | |
395 | if (iter->done) | |
396 | return 1; | |
397 | ||
398 | /* A) Look for used loop devices in /proc/partitions ("losetup -a" only) | |
399 | */ | |
400 | if (iter->flags & LOOPITER_FL_USED) { | |
401 | char buf[BUFSIZ]; | |
402 | ||
403 | if (!iter->proc) | |
404 | iter->proc = fopen(_PATH_PROC_PARTITIONS, "r"); | |
405 | ||
406 | while (iter->proc && fgets(buf, sizeof(buf), iter->proc)) { | |
407 | unsigned int m; | |
408 | char name[128]; | |
409 | ||
410 | if (sscanf(buf, " %u %*s %*s %128[^\n ]", | |
411 | &m, name) != 2 || m != LOOPDEV_MAJOR) | |
412 | continue; | |
413 | ||
414 | if (loopiter_set_device(lc, name) == 0) | |
415 | return 0; | |
416 | } | |
417 | ||
418 | goto done; | |
419 | } | |
420 | ||
421 | /* B) Classic way, try first eight loop devices (default number | |
422 | * of loop devices). This is enough for 99% of all cases. | |
423 | */ | |
424 | if (iter->default_check) { | |
425 | for (++iter->ncur; iter->ncur < LOOPDEV_DEFAULT_NNODES; | |
426 | iter->ncur++) { | |
427 | char name[16]; | |
428 | snprintf(name, sizeof(name), "loop%d", iter->ncur); | |
429 | ||
430 | if (loopiter_set_device(lc, name) == 0) | |
431 | return 0; | |
432 | } | |
433 | iter->default_check = 0; | |
434 | } | |
435 | ||
436 | /* C) the worst possibility, scan whole /dev or /dev/loop/<N> | |
437 | */ | |
438 | if (!iter->minors) { | |
439 | iter->nminors = (lc->flags & LOOPDEV_FL_DEVSUBDIR) ? | |
440 | loop_scandir(_PATH_DEV_LOOP, &iter->minors, 0) : | |
441 | loop_scandir(_PATH_DEV, &iter->minors, 1); | |
442 | iter->ncur = -1; | |
443 | } | |
444 | for (++iter->ncur; iter->ncur < iter->nminors; iter->ncur++) { | |
445 | char name[16]; | |
446 | snprintf(name, sizeof(name), "loop%d", iter->minors[iter->ncur]); | |
447 | ||
448 | if (loopiter_set_device(lc, name) == 0) | |
449 | return 0; | |
450 | } | |
451 | done: | |
452 | loopcxt_deinit_iterator(lc); | |
453 | return 1; | |
454 | } | |
455 | ||
456 | /* | |
457 | * @device: path to device | |
458 | */ | |
459 | int is_loopdev(const char *device) | |
460 | { | |
461 | struct stat st; | |
462 | ||
463 | if (!device) | |
464 | return 0; | |
465 | ||
466 | return (stat(device, &st) == 0 && | |
467 | S_ISBLK(st.st_mode) && | |
468 | major(st.st_rdev) == LOOPDEV_MAJOR); | |
469 | } | |
470 | ||
471 | /* | |
472 | * @lc: context | |
473 | * | |
474 | * Returns result from LOOP_GET_STAT64 ioctl or NULL on error. | |
475 | */ | |
476 | struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc) | |
477 | { | |
478 | int fd; | |
479 | ||
480 | if (!lc) | |
481 | return NULL; | |
482 | if (lc->has_info) | |
483 | return &lc->info; | |
484 | ||
485 | fd = loopcxt_get_fd(lc); | |
486 | if (fd < 0) | |
487 | return NULL; | |
488 | ||
489 | if (ioctl(fd, LOOP_GET_STATUS64, &lc->info) == 0) { | |
490 | lc->has_info = 1; | |
491 | return &lc->info; | |
492 | } | |
493 | ||
494 | return NULL; | |
495 | } | |
496 | ||
497 | /* | |
498 | * @lc: context | |
499 | * | |
500 | * Returns (allocated) string with path to the file assicieted | |
501 | * with the current loop device. | |
502 | */ | |
503 | char *loopcxt_get_backing_file(struct loopdev_cxt *lc) | |
504 | { | |
505 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
506 | char *res = NULL; | |
507 | ||
508 | if (sysfs) | |
fd7f0718 KZ |
509 | /* |
510 | * This is always preffered, the loop_info64 | |
511 | * has too small buffer for the filename. | |
512 | */ | |
10ee5932 KZ |
513 | res = sysfs_strdup(sysfs, "loop/backing_file"); |
514 | ||
515 | if (!res && loopcxt_ioctl_enabled(lc)) { | |
516 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
517 | ||
518 | if (lo) { | |
519 | lo->lo_file_name[LO_NAME_SIZE - 2] = '*'; | |
520 | lo->lo_file_name[LO_NAME_SIZE - 1] = '\0'; | |
521 | res = strdup((char *) lo->lo_file_name); | |
522 | } | |
523 | } | |
524 | return res; | |
525 | } | |
526 | ||
527 | /* | |
528 | * @lc: context | |
529 | * @offset: returns offset number for the given device | |
530 | * | |
531 | * Returns: <0 on error, 0 on success | |
532 | */ | |
533 | int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset) | |
534 | { | |
535 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
536 | int rc = -EINVAL; | |
537 | ||
538 | if (sysfs) | |
539 | rc = sysfs_read_u64(sysfs, "loop/offset", offset); | |
540 | ||
541 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
542 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
543 | if (lo) { | |
544 | if (offset) | |
545 | *offset = lo->lo_offset; | |
546 | return 0; | |
547 | } | |
548 | } | |
549 | ||
550 | return rc; | |
551 | } | |
552 | ||
553 | /* | |
554 | * @lc: context | |
555 | * @sizelimit: returns size limit for the given device | |
556 | * | |
557 | * Returns: <0 on error, 0 on success | |
558 | */ | |
559 | int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size) | |
560 | { | |
561 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
562 | int rc = -EINVAL; | |
563 | ||
564 | if (sysfs) | |
565 | rc = sysfs_read_u64(sysfs, "loop/sizelimit", size); | |
566 | ||
567 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
568 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
569 | if (lo) { | |
570 | if (size) | |
571 | *size = lo->lo_sizelimit; | |
572 | return 0; | |
573 | } | |
574 | } | |
575 | ||
576 | return rc; | |
577 | } | |
578 | ||
579 | /* | |
580 | * @lc: context | |
581 | * | |
582 | * Returns: 1 of the autoclear flags is set. | |
583 | */ | |
584 | int loopcxt_is_autoclear(struct loopdev_cxt *lc) | |
585 | { | |
586 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
587 | ||
588 | if (sysfs) { | |
589 | int fl; | |
590 | if (sysfs_read_int(sysfs, "loop/autoclear", &fl) == 0) | |
591 | return fl; | |
592 | } | |
593 | ||
594 | if (loopcxt_ioctl_enabled(lc)) { | |
595 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
596 | if (lo) | |
597 | return lo->lo_flags & LO_FLAGS_AUTOCLEAR; | |
598 | } | |
599 | return 0; | |
600 | } | |
601 | ||
fd7f0718 KZ |
602 | /* |
603 | * @lc: context | |
604 | * | |
605 | * Returns: 1 of the readonly flags is set. | |
606 | */ | |
607 | int loopcxt_is_readonly(struct loopdev_cxt *lc) | |
608 | { | |
609 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
610 | ||
611 | if (sysfs) { | |
612 | int fl; | |
613 | if (sysfs_read_int(sysfs, "ro", &fl) == 0) | |
614 | return fl; | |
615 | } | |
616 | ||
617 | if (loopcxt_ioctl_enabled(lc)) { | |
618 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
619 | if (lo) | |
620 | return lo->lo_flags & LO_FLAGS_READ_ONLY; | |
621 | } | |
622 | return 0; | |
623 | } | |
624 | ||
625 | /* | |
626 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
627 | */ | |
10ee5932 KZ |
628 | int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset) |
629 | { | |
630 | if (!lc) | |
631 | return -EINVAL; | |
632 | lc->info.lo_offset = offset; | |
633 | return 0; | |
634 | } | |
635 | ||
fd7f0718 KZ |
636 | /* |
637 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
638 | */ | |
10ee5932 KZ |
639 | int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit) |
640 | { | |
641 | if (!lc) | |
642 | return -EINVAL; | |
643 | lc->info.lo_sizelimit = sizelimit; | |
644 | return 0; | |
645 | } | |
646 | ||
647 | /* | |
648 | * @lc: context | |
649 | * @flags: kernel LO_FLAGS_{READ_ONLY,USE_AOPS,AUTOCLEAR} flags | |
650 | * | |
fd7f0718 KZ |
651 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
652 | * | |
10ee5932 KZ |
653 | * Returns: 0 on success, <0 on error. |
654 | */ | |
655 | int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags) | |
656 | { | |
657 | if (!lc) | |
658 | return -EINVAL; | |
659 | lc->info.lo_flags = flags; | |
660 | return 0; | |
661 | } | |
662 | ||
663 | /* | |
664 | * @lc: context | |
665 | * @filename: backing file path (the path will be canonicalized) | |
666 | * | |
fd7f0718 KZ |
667 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
668 | * | |
10ee5932 KZ |
669 | * Returns: 0 on success, <0 on error. |
670 | */ | |
671 | int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename) | |
672 | { | |
673 | if (!lc) | |
674 | return -EINVAL; | |
675 | ||
676 | lc->filename = canonicalize_path(filename); | |
677 | if (!lc->filename) | |
678 | return -errno; | |
679 | ||
680 | strncpy((char *)lc->info.lo_file_name, lc->filename, LO_NAME_SIZE); | |
681 | lc->info.lo_file_name[LO_NAME_SIZE- 1] = '\0'; | |
682 | ||
683 | return 0; | |
684 | } | |
685 | ||
686 | static int digits_only(const char *s) | |
687 | { | |
688 | while (*s) | |
689 | if (!isdigit(*s++)) | |
690 | return 0; | |
691 | return 1; | |
692 | } | |
693 | ||
694 | /* | |
695 | * @lc: context | |
696 | * @encryption: encryption name / type (see lopsetup man page) | |
697 | * @password | |
698 | * | |
fd7f0718 | 699 | * Note that the encryption functionality is deprecated an unmaintained. Use |
10ee5932 KZ |
700 | * cryptsetup (it also supports AES-loops). |
701 | * | |
fd7f0718 KZ |
702 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
703 | * | |
10ee5932 KZ |
704 | * Returns: 0 on success, <0 on error. |
705 | */ | |
706 | int loopcxt_set_encryption(struct loopdev_cxt *lc, | |
707 | const char *encryption, | |
708 | const char *password) | |
709 | { | |
710 | if (!lc) | |
711 | return -EINVAL; | |
712 | ||
713 | if (encryption && *encryption) { | |
714 | if (digits_only(encryption)) { | |
715 | lc->info.lo_encrypt_type = atoi(encryption); | |
716 | } else { | |
717 | lc->info.lo_encrypt_type = LO_CRYPT_CRYPTOAPI; | |
718 | snprintf((char *)lc->info.lo_crypt_name, LO_NAME_SIZE, | |
719 | "%s", encryption); | |
720 | } | |
721 | } | |
722 | ||
723 | switch (lc->info.lo_encrypt_type) { | |
724 | case LO_CRYPT_NONE: | |
725 | lc->info.lo_encrypt_key_size = 0; | |
726 | break; | |
727 | default: | |
728 | memset(lc->info.lo_encrypt_key, 0, LO_KEY_SIZE); | |
729 | strncpy((char *)lc->info.lo_encrypt_key, password, LO_KEY_SIZE); | |
730 | lc->info.lo_encrypt_key[LO_KEY_SIZE - 1] = '\0'; | |
731 | lc->info.lo_encrypt_key_size = LO_KEY_SIZE; | |
732 | break; | |
733 | } | |
734 | return 0; | |
735 | } | |
736 | ||
737 | /* | |
738 | * @cl: context | |
739 | * | |
740 | * Associate the current device (see loopcxt_{set,get}_device()) with | |
741 | * a file (see loopcxt_set_backing_file()). | |
742 | * | |
fd7f0718 KZ |
743 | * The device is initialized read-write by default. If you want read-only |
744 | * device then set LO_FLAGS_READ_ONLY by loopcxt_set_flags(). The LOOPDEV_FL_* | |
745 | * flags are ignored and modified according to LO_FLAGS_*. | |
746 | * | |
747 | * If the device is already open by loopcxt_get_fd() then this setup device | |
748 | * function will re-open the device to fix read/write mode. | |
749 | * | |
750 | * The device is also initialized read-only if the backing file is not | |
751 | * possible to open read-write (e.g. read-only FS). | |
10ee5932 KZ |
752 | * |
753 | * Returns: <0 on error, 0 on success. | |
754 | */ | |
755 | int loopcxt_setup_device(struct loopdev_cxt *lc) | |
756 | { | |
fd7f0718 | 757 | int file_fd, dev_fd, mode = O_RDWR, rc = -1; |
10ee5932 KZ |
758 | |
759 | if (!lc || !*lc->device || !lc->filename) | |
760 | return -EINVAL; | |
761 | ||
762 | /* | |
763 | * Open backing file and device | |
764 | */ | |
fd7f0718 KZ |
765 | if (lc->info.lo_flags & LO_FLAGS_READ_ONLY) |
766 | mode = O_RDONLY; | |
10ee5932 KZ |
767 | |
768 | if ((file_fd = open(lc->filename, mode)) < 0) { | |
769 | if (mode != O_RDONLY && (errno == EROFS || errno == EACCES)) | |
770 | file_fd = open(lc->filename, mode = O_RDONLY); | |
771 | ||
772 | if (file_fd < 0) | |
773 | return -errno; | |
774 | } | |
775 | ||
fd7f0718 KZ |
776 | if (lc->fd != -1 && lc->mode != mode) { |
777 | close(lc->fd); | |
778 | lc->fd = -1; | |
779 | lc->mode = 0; | |
780 | } | |
781 | ||
10ee5932 | 782 | if (mode == O_RDONLY) { |
fd7f0718 KZ |
783 | lc->flags |= LOOPDEV_FL_RDONLY; /* open() mode */ |
784 | lc->info.lo_flags |= LO_FLAGS_READ_ONLY; /* kernel loopdev mode */ | |
785 | } else { | |
786 | lc->flags |= LOOPDEV_FL_RDWR; /* open() mode */ | |
787 | lc->info.lo_flags &= ~LO_FLAGS_READ_ONLY; | |
788 | lc->flags &= ~LOOPDEV_FL_RDONLY; | |
789 | } | |
10ee5932 KZ |
790 | |
791 | dev_fd = loopcxt_get_fd(lc); | |
792 | if (dev_fd < 0) { | |
793 | rc = -errno; | |
794 | goto err; | |
795 | } | |
796 | ||
797 | /* | |
798 | * Set FD | |
799 | */ | |
800 | if (ioctl(dev_fd, LOOP_SET_FD, file_fd) < 0) { | |
801 | rc = -errno; | |
802 | goto err; | |
803 | } | |
804 | close(file_fd); | |
805 | file_fd = -1; | |
806 | ||
807 | if (ioctl(dev_fd, LOOP_SET_STATUS64, &lc->info)) | |
808 | goto err; | |
809 | ||
810 | memset(&lc->info, 0, sizeof(lc->info)); | |
811 | lc->has_info = 0; | |
812 | ||
813 | return 0; | |
814 | err: | |
815 | if (file_fd >= 0) | |
816 | close(file_fd); | |
817 | if (dev_fd >= 0) | |
818 | ioctl(dev_fd, LOOP_CLR_FD, 0); | |
819 | ||
820 | return rc; | |
821 | } | |
822 | ||
823 | int loopcxt_delete_device(struct loopdev_cxt *lc) | |
824 | { | |
825 | int fd = loopcxt_get_fd(lc); | |
826 | ||
827 | if (fd < 0) | |
828 | return -EINVAL; | |
829 | ||
830 | if (ioctl(fd, LOOP_CLR_FD, 0) < 0) | |
831 | return -errno; | |
832 | return 0; | |
833 | } | |
834 | ||
835 | int loopcxt_find_unused(struct loopdev_cxt *lc) | |
836 | { | |
837 | int rc; | |
838 | ||
839 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_FREE); | |
840 | if (rc) | |
841 | return rc; | |
842 | ||
843 | rc = loopcxt_next(lc); | |
844 | loopcxt_deinit_iterator(lc); | |
845 | ||
846 | return rc; | |
847 | } | |
848 | ||
849 | ||
850 | ||
851 | /* | |
852 | * Return: TRUE/FALSE | |
853 | */ | |
854 | int loopdev_is_autoclear(const char *device) | |
855 | { | |
856 | struct loopdev_cxt lc; | |
857 | int rc; | |
858 | ||
859 | if (!device) | |
860 | return 0; | |
861 | ||
862 | loopcxt_init(&lc, 0); | |
863 | loopcxt_set_device(&lc, device); | |
864 | rc = loopcxt_is_autoclear(&lc); | |
865 | loopcxt_deinit(&lc); | |
866 | ||
867 | return rc; | |
868 | } | |
869 | ||
870 | char *loopdev_get_backing_file(const char *device) | |
871 | { | |
872 | struct loopdev_cxt lc; | |
873 | char *res; | |
874 | ||
875 | if (!device) | |
876 | return NULL; | |
877 | ||
878 | loopcxt_init(&lc, 0); | |
879 | loopcxt_set_device(&lc, device); | |
880 | res = loopcxt_get_backing_file(&lc); | |
881 | loopcxt_deinit(&lc); | |
882 | ||
883 | return res; | |
884 | } | |
885 | ||
886 | /* | |
887 | * Returns: TRUE/FALSE | |
888 | */ | |
889 | int loopdev_is_used(const char *device, const char *filename, | |
890 | uint64_t offset, int flags) | |
891 | { | |
892 | struct loopdev_cxt lc; | |
893 | char *backing = NULL; | |
894 | int rc = 0; | |
895 | ||
896 | if (!device) | |
897 | return 0; | |
898 | ||
899 | loopcxt_init(&lc, 0); | |
900 | loopcxt_set_device(&lc, device); | |
901 | ||
902 | backing = loopcxt_get_backing_file(&lc); | |
903 | if (!backing) | |
904 | goto done; | |
905 | if (filename && strcmp(filename, backing) != 0) | |
906 | goto done; | |
907 | if (flags & LOOPDEV_FL_OFFSET) { | |
908 | uint64_t off; | |
909 | ||
910 | if (loopcxt_get_offset(&lc, &off) != 0 || off != offset) | |
911 | goto done; | |
912 | } | |
913 | ||
914 | rc = 1; | |
915 | done: | |
916 | free(backing); | |
917 | loopcxt_deinit(&lc); | |
918 | ||
919 | return rc; | |
920 | } | |
921 | ||
922 | int loopdev_delete(const char *device) | |
923 | { | |
924 | struct loopdev_cxt lc; | |
925 | int rc; | |
926 | ||
927 | loopcxt_init(&lc, 0); | |
928 | rc = loopcxt_set_device(&lc, device); | |
929 | if (!rc) | |
930 | rc = loopcxt_delete_device(&lc); | |
931 | loopcxt_deinit(&lc); | |
932 | return rc; | |
933 | } | |
934 | ||
935 | /* | |
936 | * Returns: 0 = success, < 0 error, 1 not found | |
937 | */ | |
938 | int loopcxt_find_by_backing_file(struct loopdev_cxt *lc, const char *filename, | |
939 | uint64_t offset, int flags) | |
940 | { | |
941 | int rc; | |
942 | ||
943 | if (!filename) | |
944 | return -EINVAL; | |
945 | ||
946 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); | |
947 | if (rc) | |
948 | return rc; | |
949 | ||
950 | while((rc = loopcxt_next(lc)) == 0) { | |
951 | char *backing = loopcxt_get_backing_file(lc); | |
952 | ||
953 | if (!backing || strcmp(backing, filename)) { | |
954 | free(backing); | |
955 | continue; | |
956 | } | |
957 | ||
958 | free(backing); | |
959 | ||
960 | if (flags & LOOPDEV_FL_OFFSET) { | |
961 | uint64_t off; | |
962 | if (loopcxt_get_offset(lc, &off) != 0 || offset != off) | |
963 | continue; | |
964 | } | |
965 | ||
966 | rc = 0; | |
967 | break; | |
968 | } | |
969 | ||
970 | loopcxt_deinit_iterator(lc); | |
971 | return rc; | |
972 | } | |
973 | ||
974 | /* | |
975 | * Returns allocated string with device name | |
976 | */ | |
977 | char *loopdev_find_by_backing_file(const char *filename, uint64_t offset, int flags) | |
978 | { | |
979 | struct loopdev_cxt lc; | |
980 | char *res = NULL; | |
981 | ||
982 | if (!filename) | |
983 | return NULL; | |
984 | ||
985 | loopcxt_init(&lc, 0); | |
986 | if (loopcxt_find_by_backing_file(&lc, filename, offset, flags)) | |
987 | res = loopcxt_strdup_device(&lc); | |
988 | loopcxt_deinit(&lc); | |
989 | ||
990 | return res; | |
991 | } | |
992 | ||
993 | ||
994 | #ifdef TEST_PROGRAM_LOOPDEV | |
995 | #include <errno.h> | |
996 | #include <err.h> | |
10ee5932 KZ |
997 | |
998 | static void test_loop_info(const char *device, int flags) | |
999 | { | |
1000 | struct loopdev_cxt lc; | |
1001 | char *p; | |
1002 | uint64_t u64; | |
1003 | ||
1004 | loopcxt_init(&lc, flags); | |
1005 | if (loopcxt_set_device(&lc, device)) | |
1006 | err(EXIT_FAILURE, "failed to set device"); | |
1007 | ||
1008 | p = loopcxt_get_backing_file(&lc); | |
1009 | printf("\tBACKING FILE: %s\n", p); | |
1010 | free(p); | |
1011 | ||
1012 | if (loopcxt_get_offset(&lc, &u64) == 0) | |
1013 | printf("\tOFFSET: %jd\n", u64); | |
1014 | ||
1015 | if (loopcxt_get_sizelimit(&lc, &u64) == 0) | |
1016 | printf("\tSIZE LIMIT: %jd\n", u64); | |
1017 | ||
1018 | printf("\tAUTOCLEAR: %s\n", loopcxt_is_autoclear(&lc) ? "YES" : "NOT"); | |
1019 | ||
1020 | loopcxt_deinit(&lc); | |
1021 | } | |
1022 | ||
1023 | static void test_loop_scan(int flags) | |
1024 | { | |
1025 | struct loopdev_cxt lc; | |
1026 | int rc; | |
1027 | ||
1028 | loopcxt_init(&lc, 0); | |
1029 | ||
1030 | if (loopcxt_init_iterator(&lc, flags)) | |
1031 | err(EXIT_FAILURE, "iterator initlization failed"); | |
1032 | ||
1033 | while((rc = loopcxt_next(&lc)) == 0) { | |
1034 | const char *device = loopcxt_get_device(&lc); | |
1035 | ||
1036 | if (flags & LOOPITER_FL_USED) { | |
1037 | char *backing = loopcxt_get_backing_file(&lc); | |
1038 | printf("\t%s: %s\n", device, backing); | |
1039 | free(backing); | |
1040 | } else | |
1041 | printf("\t%s\n", device); | |
1042 | } | |
1043 | ||
1044 | if (rc < 0) | |
1045 | err(EXIT_FAILURE, "loopdevs scanning failed"); | |
1046 | ||
1047 | loopcxt_deinit(&lc); | |
1048 | } | |
1049 | ||
1050 | static int test_loop_setup(const char *filename, const char *device) | |
1051 | { | |
1052 | struct loopdev_cxt lc; | |
1053 | int rc = 0; | |
1054 | ||
1055 | loopcxt_init(&lc, 0); | |
1056 | ||
10ee5932 KZ |
1057 | if (device) { |
1058 | rc = loopcxt_set_device(&lc, device); | |
1059 | if (rc) | |
1060 | err(EXIT_FAILURE, "failed to set device: %s", device); | |
1061 | } | |
1062 | ||
1063 | do { | |
1064 | if (!device) { | |
1065 | rc = loopcxt_find_unused(&lc); | |
1066 | if (rc) | |
ad2d0d85 | 1067 | err(EXIT_FAILURE, "failed to find unused device"); |
10ee5932 KZ |
1068 | printf("Trying to use '%s'\n", loopcxt_get_device(&lc)); |
1069 | } | |
1070 | ||
fd7f0718 KZ |
1071 | if (loopcxt_set_backing_file(&lc, filename)) |
1072 | err(EXIT_FAILURE, "failed to set backing file"); | |
1073 | ||
10ee5932 KZ |
1074 | rc = loopcxt_setup_device(&lc); |
1075 | if (rc == 0) | |
1076 | break; /* success */ | |
1077 | ||
1078 | if (device || rc != -EBUSY) | |
1079 | err(EXIT_FAILURE, "failed to setup device for %s", | |
1080 | lc.filename); | |
1081 | ||
1082 | printf("device stolen...trying again\n"); | |
1083 | } while (1); | |
1084 | ||
1085 | loopcxt_deinit(&lc); | |
1086 | ||
1087 | return 0; | |
1088 | } | |
1089 | ||
1090 | int main(int argc, char *argv[]) | |
1091 | { | |
1092 | if (argc < 2) | |
1093 | goto usage; | |
1094 | ||
1095 | if (argc == 3 && strcmp(argv[1], "--info") == 0) { | |
1096 | printf("---sysfs & ioctl:---\n"); | |
1097 | test_loop_info(argv[2], 0); | |
1098 | printf("---sysfs only:---\n"); | |
1099 | test_loop_info(argv[2], LOOPDEV_FL_NOIOCTL); | |
1100 | printf("---ioctl only:---\n"); | |
1101 | test_loop_info(argv[2], LOOPDEV_FL_NOSYSFS); | |
1102 | ||
1103 | } else if (argc == 2 && strcmp(argv[1], "--used") == 0) { | |
1104 | printf("---all used devices---\n"); | |
1105 | test_loop_scan(LOOPITER_FL_USED); | |
1106 | ||
1107 | } else if (argc == 2 && strcmp(argv[1], "--free") == 0) { | |
1108 | printf("---all free devices---\n"); | |
1109 | test_loop_scan(LOOPITER_FL_FREE); | |
1110 | ||
1111 | } else if (argc >= 3 && strcmp(argv[1], "--setup") == 0) { | |
1112 | test_loop_setup(argv[2], argv[3]); | |
1113 | ||
1114 | } else if (argc == 3 && strcmp(argv[1], "--delete") == 0) { | |
1115 | if (loopdev_delete(argv[2])) | |
1116 | errx(EXIT_FAILURE, "failed to deinitialize device %s", argv[2]); | |
1117 | } else | |
1118 | goto usage; | |
1119 | ||
1120 | return EXIT_SUCCESS; | |
1121 | ||
1122 | usage: | |
1123 | errx(EXIT_FAILURE, "usage: \n" | |
1124 | " %1$s --info <device>\n" | |
1125 | " %1$s --free\n" | |
1126 | " %1$s --used\n" | |
1127 | " %1$s --setup <filename> [<device>]\n" | |
1128 | " %1$s --delete\n", | |
1129 | argv[0]); | |
1130 | } | |
1131 | ||
1132 | #endif /* TEST_PROGRAM */ |