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Commit | Line | Data |
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10ee5932 | 1 | /* |
0f23ee0c KZ |
2 | * No copyright is claimed. This code is in the public domain; do with |
3 | * it what you wish. | |
4 | * | |
5 | * Written by Karel Zak <kzak@redhat.com> | |
10ee5932 KZ |
6 | * |
7 | * -- based on mount/losetup.c | |
8 | * | |
9 | * Simple library for work with loop devices. | |
10 | * | |
11 | * - requires kernel 2.6.x | |
12 | * - reads info from /sys/block/loop<N>/loop/<attr> (new kernels) | |
13 | * - reads info by ioctl | |
14 | * - supports *unlimited* number of loop devices | |
15 | * - supports /dev/loop<N> as well as /dev/loop/<N> | |
16 | * - minimize overhead (fd, loopinfo, ... are shared for all operations) | |
17 | * - setup (associate device and backing file) | |
18 | * - delete (dis-associate file) | |
19 | * - old LOOP_{SET,GET}_STATUS (32bit) ioctls are unsupported | |
20 | * - extendible | |
21 | */ | |
22 | #include <stdio.h> | |
23 | #include <stdint.h> | |
24 | #include <string.h> | |
25 | #include <ctype.h> | |
26 | #include <fcntl.h> | |
10ee5932 KZ |
27 | #include <stdlib.h> |
28 | #include <unistd.h> | |
29 | #include <sys/ioctl.h> | |
30 | #include <sys/stat.h> | |
31 | #include <sys/mman.h> | |
32 | #include <sys/sysmacros.h> | |
33 | #include <inttypes.h> | |
34 | #include <dirent.h> | |
35 | #include <linux/posix_types.h> | |
36 | ||
37 | #include "linux_version.h" | |
38 | #include "c.h" | |
39 | #include "sysfs.h" | |
40 | #include "pathnames.h" | |
41 | #include "loopdev.h" | |
42 | #include "canonicalize.h" | |
e4062c72 | 43 | #include "at.h" |
293714c0 | 44 | #include "blkdev.h" |
0bf03740 | 45 | #include "debug.h" |
10ee5932 | 46 | |
0bf03740 KZ |
47 | /* |
48 | * Debug stuff (based on include/debug.h) | |
49 | */ | |
50 | UL_DEBUG_DEFINE_MASK(loopdev); | |
51 | UL_DEBUG_DEFINE_MASKNAMES(loopdev) = UL_DEBUG_EMPTY_MASKNAMES; | |
aee31ddc | 52 | |
0bf03740 KZ |
53 | #define LOOPDEV_DEBUG_INIT (1 << 1) |
54 | #define LOOPDEV_DEBUG_CXT (1 << 2) | |
55 | #define LOOPDEV_DEBUG_ITER (1 << 3) | |
56 | #define LOOPDEV_DEBUG_SETUP (1 << 4) | |
57 | #define SFDISKPROG_DEBUG_ALL 0xFFFF | |
aee31ddc | 58 | |
0bf03740 KZ |
59 | #define DBG(m, x) __UL_DBG(loopdev, LOOPDEV_DEBUG_, m, x) |
60 | #define ON_DBG(m, x) __UL_DBG_CALL(loopdev, LOOPDEV_DEBUG_, m, x) | |
aee31ddc | 61 | |
0bf03740 | 62 | static void loopdev_init_debug(void) |
aee31ddc | 63 | { |
0bf03740 KZ |
64 | if (loopdev_debug_mask) |
65 | return; | |
66 | __UL_INIT_DEBUG(loopdev, LOOPDEV_DEBUG_, 0, LOOPDEV_DEBUG); | |
aee31ddc KZ |
67 | } |
68 | ||
e4062c72 KZ |
69 | /* |
70 | * see loopcxt_init() | |
71 | */ | |
10ee5932 | 72 | #define loopcxt_ioctl_enabled(_lc) (!((_lc)->flags & LOOPDEV_FL_NOIOCTL)) |
e4062c72 KZ |
73 | #define loopcxt_sysfs_available(_lc) (!((_lc)->flags & LOOPDEV_FL_NOSYSFS)) \ |
74 | && !loopcxt_ioctl_enabled(_lc) | |
10ee5932 KZ |
75 | |
76 | /* | |
77 | * @lc: context | |
78 | * @device: device name, absolute device path or NULL to reset the current setting | |
79 | * | |
80 | * Sets device, absolute paths (e.g. "/dev/loop<N>") are unchanged, device | |
81 | * names ("loop<N>") are converted to the path (/dev/loop<N> or to | |
82 | * /dev/loop/<N>) | |
83 | * | |
85794fb0 KZ |
84 | * This sets the device name, but does not check if the device exists! |
85 | * | |
10ee5932 KZ |
86 | * Returns: <0 on error, 0 on success |
87 | */ | |
88 | int loopcxt_set_device(struct loopdev_cxt *lc, const char *device) | |
89 | { | |
90 | if (!lc) | |
91 | return -EINVAL; | |
92 | ||
f4bf9592 | 93 | if (lc->fd >= 0) { |
10ee5932 | 94 | close(lc->fd); |
0bf03740 | 95 | DBG(CXT, ul_debugobj(lc, "closing old open fd")); |
f4bf9592 | 96 | } |
10ee5932 | 97 | lc->fd = -1; |
fd7f0718 | 98 | lc->mode = 0; |
10ee5932 | 99 | lc->has_info = 0; |
6c224de1 | 100 | lc->info_failed = 0; |
10ee5932 | 101 | *lc->device = '\0'; |
fd7f0718 | 102 | memset(&lc->info, 0, sizeof(lc->info)); |
10ee5932 KZ |
103 | |
104 | /* set new */ | |
105 | if (device) { | |
106 | if (*device != '/') { | |
107 | const char *dir = _PATH_DEV; | |
108 | ||
109 | /* compose device name for /dev/loop<n> or /dev/loop/<n> */ | |
110 | if (lc->flags & LOOPDEV_FL_DEVSUBDIR) { | |
111 | if (strlen(device) < 5) | |
112 | return -1; | |
113 | device += 4; | |
114 | dir = _PATH_DEV_LOOP "/"; /* _PATH_DEV uses tailing slash */ | |
115 | } | |
116 | snprintf(lc->device, sizeof(lc->device), "%s%s", | |
117 | dir, device); | |
118 | } else { | |
119 | strncpy(lc->device, device, sizeof(lc->device)); | |
120 | lc->device[sizeof(lc->device) - 1] = '\0'; | |
121 | } | |
0bf03740 | 122 | DBG(CXT, ul_debugobj(lc, "%s name assigned", device)); |
10ee5932 KZ |
123 | } |
124 | ||
125 | sysfs_deinit(&lc->sysfs); | |
126 | return 0; | |
127 | } | |
128 | ||
c7e0925d KZ |
129 | int loopcxt_has_device(struct loopdev_cxt *lc) |
130 | { | |
131 | return lc && *lc->device; | |
132 | } | |
133 | ||
10ee5932 KZ |
134 | /* |
135 | * @lc: context | |
136 | * @flags: LOOPDEV_FL_* flags | |
137 | * | |
138 | * Initilize loop handler. | |
139 | * | |
fd7f0718 KZ |
140 | * We have two sets of the flags: |
141 | * | |
142 | * * LOOPDEV_FL_* flags control loopcxt_* API behavior | |
143 | * | |
144 | * * LO_FLAGS_* are kernel flags used for LOOP_{SET,GET}_STAT64 ioctls | |
145 | * | |
146 | * Note about LOOPDEV_FL_{RDONLY,RDWR} flags. These flags are used for open(2) | |
147 | * syscall to open loop device. By default is the device open read-only. | |
148 | * | |
149 | * The expection is loopcxt_setup_device(), where the device is open read-write | |
150 | * if LO_FLAGS_READ_ONLY flags is not set (see loopcxt_set_flags()). | |
151 | * | |
10ee5932 KZ |
152 | * Returns: <0 on error, 0 on success. |
153 | */ | |
154 | int loopcxt_init(struct loopdev_cxt *lc, int flags) | |
155 | { | |
defa0710 | 156 | int rc; |
0b14bf7a | 157 | struct stat st; |
6219c25e | 158 | struct loopdev_cxt dummy = UL_LOOPDEVCXT_EMPTY; |
0b14bf7a | 159 | |
10ee5932 KZ |
160 | if (!lc) |
161 | return -EINVAL; | |
162 | ||
0bf03740 KZ |
163 | loopdev_init_debug(); |
164 | DBG(CXT, ul_debugobj(lc, "initialize context")); | |
165 | ||
6219c25e | 166 | memcpy(lc, &dummy, sizeof(dummy)); |
10ee5932 | 167 | lc->flags = flags; |
defa0710 KZ |
168 | |
169 | rc = loopcxt_set_device(lc, NULL); | |
170 | if (rc) | |
171 | return rc; | |
10ee5932 | 172 | |
df0f2ad7 KZ |
173 | if (stat(_PATH_SYS_BLOCK, &st) || !S_ISDIR(st.st_mode)) { |
174 | lc->flags |= LOOPDEV_FL_NOSYSFS; | |
175 | lc->flags &= ~LOOPDEV_FL_NOIOCTL; | |
0bf03740 | 176 | DBG(CXT, ul_debugobj(lc, "init: disable /sys usage")); |
df0f2ad7 KZ |
177 | } |
178 | ||
82b4082e | 179 | if (!(lc->flags & LOOPDEV_FL_NOSYSFS) && |
f4bf9592 | 180 | get_linux_version() >= KERNEL_VERSION(2,6,37)) { |
10ee5932 KZ |
181 | /* |
182 | * Use only sysfs for basic information about loop devices | |
183 | */ | |
184 | lc->flags |= LOOPDEV_FL_NOIOCTL; | |
0bf03740 | 185 | DBG(CXT, ul_debugobj(lc, "init: ignore ioctls")); |
f4bf9592 | 186 | } |
10ee5932 | 187 | |
f4bf9592 | 188 | if (!(lc->flags & LOOPDEV_FL_CONTROL) && !stat(_PATH_DEV_LOOPCTL, &st)) { |
0b14bf7a | 189 | lc->flags |= LOOPDEV_FL_CONTROL; |
0bf03740 | 190 | DBG(CXT, ul_debugobj(lc, "init: loop-control detected ")); |
f4bf9592 | 191 | } |
0b14bf7a | 192 | |
10ee5932 KZ |
193 | return 0; |
194 | } | |
195 | ||
196 | /* | |
197 | * @lc: context | |
198 | * | |
199 | * Deinitialize loop context | |
200 | */ | |
201 | void loopcxt_deinit(struct loopdev_cxt *lc) | |
202 | { | |
82756a74 KZ |
203 | int errsv = errno; |
204 | ||
10ee5932 KZ |
205 | if (!lc) |
206 | return; | |
207 | ||
0bf03740 | 208 | DBG(CXT, ul_debugobj(lc, "de-initialize")); |
aee31ddc | 209 | |
10ee5932 KZ |
210 | free(lc->filename); |
211 | lc->filename = NULL; | |
212 | ||
defa0710 | 213 | ignore_result( loopcxt_set_device(lc, NULL) ); |
10ee5932 | 214 | loopcxt_deinit_iterator(lc); |
82756a74 KZ |
215 | |
216 | errno = errsv; | |
10ee5932 KZ |
217 | } |
218 | ||
219 | /* | |
220 | * @lc: context | |
221 | * | |
222 | * Returns newly allocated device path. | |
223 | */ | |
224 | char *loopcxt_strdup_device(struct loopdev_cxt *lc) | |
225 | { | |
cba69bb5 | 226 | if (!lc || !*lc->device) |
10ee5932 KZ |
227 | return NULL; |
228 | return strdup(lc->device); | |
229 | } | |
230 | ||
231 | /* | |
232 | * @lc: context | |
233 | * | |
234 | * Returns pointer device name in the @lc struct. | |
235 | */ | |
236 | const char *loopcxt_get_device(struct loopdev_cxt *lc) | |
237 | { | |
cba69bb5 | 238 | return lc && *lc->device ? lc->device : NULL; |
10ee5932 KZ |
239 | } |
240 | ||
241 | /* | |
242 | * @lc: context | |
243 | * | |
244 | * Returns pointer to the sysfs context (see lib/sysfs.c) | |
245 | */ | |
246 | struct sysfs_cxt *loopcxt_get_sysfs(struct loopdev_cxt *lc) | |
247 | { | |
248 | if (!lc || !*lc->device || (lc->flags & LOOPDEV_FL_NOSYSFS)) | |
249 | return NULL; | |
250 | ||
251 | if (!lc->sysfs.devno) { | |
252 | dev_t devno = sysfs_devname_to_devno(lc->device, NULL); | |
aee31ddc | 253 | if (!devno) { |
0bf03740 | 254 | DBG(CXT, ul_debugobj(lc, "sysfs: failed devname to devno")); |
10ee5932 | 255 | return NULL; |
aee31ddc KZ |
256 | } |
257 | if (sysfs_init(&lc->sysfs, devno, NULL)) { | |
0bf03740 | 258 | DBG(CXT, ul_debugobj(lc, "sysfs: init failed")); |
10ee5932 | 259 | return NULL; |
aee31ddc | 260 | } |
10ee5932 | 261 | } |
aee31ddc | 262 | |
10ee5932 KZ |
263 | return &lc->sysfs; |
264 | } | |
265 | ||
266 | /* | |
267 | * @lc: context | |
268 | * | |
269 | * Returns: file descriptor to the open loop device or <0 on error. The mode | |
270 | * depends on LOOPDEV_FL_{RDWR,RDONLY} context flags. Default is | |
271 | * read-only. | |
272 | */ | |
273 | int loopcxt_get_fd(struct loopdev_cxt *lc) | |
274 | { | |
275 | if (!lc || !*lc->device) | |
fd7f0718 | 276 | return -EINVAL; |
10ee5932 | 277 | |
fd7f0718 KZ |
278 | if (lc->fd < 0) { |
279 | lc->mode = lc->flags & LOOPDEV_FL_RDWR ? O_RDWR : O_RDONLY; | |
b1fa3e22 | 280 | lc->fd = open(lc->device, lc->mode | O_CLOEXEC); |
0bf03740 | 281 | DBG(CXT, ul_debugobj(lc, "open %s [%s]: %m", lc->device, |
663bf040 | 282 | lc->flags & LOOPDEV_FL_RDWR ? "rw" : "ro")); |
fd7f0718 | 283 | } |
10ee5932 KZ |
284 | return lc->fd; |
285 | } | |
286 | ||
fd7f0718 KZ |
287 | int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, int mode) |
288 | { | |
289 | if (!lc) | |
290 | return -EINVAL; | |
291 | ||
292 | lc->fd = fd; | |
293 | lc->mode = mode; | |
294 | return 0; | |
295 | } | |
296 | ||
10ee5932 KZ |
297 | /* |
298 | * @lc: context | |
299 | * @flags: LOOPITER_FL_* flags | |
300 | * | |
301 | * Iterator allows to scan list of the free or used loop devices. | |
302 | * | |
303 | * Returns: <0 on error, 0 on success | |
304 | */ | |
305 | int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags) | |
306 | { | |
307 | struct loopdev_iter *iter; | |
308 | struct stat st; | |
309 | ||
310 | if (!lc) | |
311 | return -EINVAL; | |
312 | ||
aee31ddc | 313 | |
10ee5932 | 314 | iter = &lc->iter; |
0bf03740 | 315 | DBG(ITER, ul_debugobj(iter, "initialize")); |
10ee5932 KZ |
316 | |
317 | /* always zeroize | |
318 | */ | |
319 | memset(iter, 0, sizeof(*iter)); | |
320 | iter->ncur = -1; | |
321 | iter->flags = flags; | |
322 | iter->default_check = 1; | |
323 | ||
324 | if (!lc->extra_check) { | |
325 | /* | |
326 | * Check for /dev/loop/<N> subdirectory | |
327 | */ | |
82b4082e | 328 | if (!(lc->flags & LOOPDEV_FL_DEVSUBDIR) && |
10ee5932 KZ |
329 | stat(_PATH_DEV_LOOP, &st) == 0 && S_ISDIR(st.st_mode)) |
330 | lc->flags |= LOOPDEV_FL_DEVSUBDIR; | |
331 | ||
332 | lc->extra_check = 1; | |
333 | } | |
334 | return 0; | |
335 | } | |
336 | ||
337 | /* | |
338 | * @lc: context | |
339 | * | |
340 | * Returns: <0 on error, 0 on success | |
341 | */ | |
342 | int loopcxt_deinit_iterator(struct loopdev_cxt *lc) | |
343 | { | |
7552258a | 344 | struct loopdev_iter *iter; |
10ee5932 KZ |
345 | |
346 | if (!lc) | |
347 | return -EINVAL; | |
348 | ||
349 | iter = &lc->iter; | |
0bf03740 | 350 | DBG(ITER, ul_debugobj(iter, "de-initialize")); |
10ee5932 KZ |
351 | |
352 | free(iter->minors); | |
353 | if (iter->proc) | |
354 | fclose(iter->proc); | |
e4062c72 KZ |
355 | if (iter->sysblock) |
356 | closedir(iter->sysblock); | |
10ee5932 KZ |
357 | iter->minors = NULL; |
358 | iter->proc = NULL; | |
e4062c72 | 359 | iter->sysblock = NULL; |
10ee5932 KZ |
360 | iter->done = 1; |
361 | return 0; | |
362 | } | |
363 | ||
364 | /* | |
365 | * Same as loopcxt_set_device, but also checks if the device is | |
366 | * associeted with any file. | |
367 | * | |
368 | * Returns: <0 on error, 0 on success, 1 device does not match with | |
369 | * LOOPITER_FL_{USED,FREE} flags. | |
370 | */ | |
371 | static int loopiter_set_device(struct loopdev_cxt *lc, const char *device) | |
372 | { | |
373 | int rc = loopcxt_set_device(lc, device); | |
374 | int used; | |
375 | ||
376 | if (rc) | |
377 | return rc; | |
378 | ||
379 | if (!(lc->iter.flags & LOOPITER_FL_USED) && | |
380 | !(lc->iter.flags & LOOPITER_FL_FREE)) | |
381 | return 0; /* caller does not care about device status */ | |
382 | ||
85794fb0 | 383 | if (!is_loopdev(lc->device)) { |
0bf03740 | 384 | DBG(ITER, ul_debugobj(&lc->iter, "%s does not exist", lc->device)); |
85794fb0 KZ |
385 | return -errno; |
386 | } | |
387 | ||
0bf03740 | 388 | DBG(ITER, ul_debugobj(&lc->iter, "%s exist", lc->device)); |
85794fb0 | 389 | |
10ee5932 KZ |
390 | used = loopcxt_get_offset(lc, NULL) == 0; |
391 | ||
392 | if ((lc->iter.flags & LOOPITER_FL_USED) && used) | |
393 | return 0; | |
394 | ||
395 | if ((lc->iter.flags & LOOPITER_FL_FREE) && !used) | |
396 | return 0; | |
397 | ||
0bf03740 KZ |
398 | DBG(ITER, ul_debugobj(&lc->iter, "failed to use %s device", lc->device)); |
399 | ||
defa0710 | 400 | ignore_result( loopcxt_set_device(lc, NULL) ); |
10ee5932 KZ |
401 | return 1; |
402 | } | |
403 | ||
404 | static int cmpnum(const void *p1, const void *p2) | |
405 | { | |
33487796 KZ |
406 | return (((* (int *) p1) > (* (int *) p2)) - |
407 | ((* (int *) p1) < (* (int *) p2))); | |
10ee5932 KZ |
408 | } |
409 | ||
410 | /* | |
411 | * The classic scandir() is more expensive and less portable. | |
412 | * We needn't full loop device names -- loop numbers (loop<N>) | |
413 | * are enough. | |
414 | */ | |
415 | static int loop_scandir(const char *dirname, int **ary, int hasprefix) | |
416 | { | |
417 | DIR *dir; | |
418 | struct dirent *d; | |
419 | unsigned int n, count = 0, arylen = 0; | |
420 | ||
421 | if (!dirname || !ary) | |
422 | return 0; | |
0bf03740 KZ |
423 | |
424 | DBG(ITER, ul_debug("scan dir: %s", dirname)); | |
425 | ||
10ee5932 KZ |
426 | dir = opendir(dirname); |
427 | if (!dir) | |
428 | return 0; | |
10ee5932 KZ |
429 | free(*ary); |
430 | *ary = NULL; | |
431 | ||
432 | while((d = readdir(dir))) { | |
433 | #ifdef _DIRENT_HAVE_D_TYPE | |
434 | if (d->d_type != DT_BLK && d->d_type != DT_UNKNOWN && | |
435 | d->d_type != DT_LNK) | |
436 | continue; | |
437 | #endif | |
438 | if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, "..")) | |
439 | continue; | |
440 | ||
441 | if (hasprefix) { | |
442 | /* /dev/loop<N> */ | |
443 | if (sscanf(d->d_name, "loop%u", &n) != 1) | |
444 | continue; | |
445 | } else { | |
446 | /* /dev/loop/<N> */ | |
447 | char *end = NULL; | |
448 | ||
f0fe8ab5 | 449 | errno = 0; |
10ee5932 KZ |
450 | n = strtol(d->d_name, &end, 10); |
451 | if (d->d_name == end || (end && *end) || errno) | |
452 | continue; | |
453 | } | |
454 | if (n < LOOPDEV_DEFAULT_NNODES) | |
455 | continue; /* ignore loop<0..7> */ | |
456 | ||
457 | if (count + 1 > arylen) { | |
458 | int *tmp; | |
459 | ||
460 | arylen += 1; | |
461 | ||
462 | tmp = realloc(*ary, arylen * sizeof(int)); | |
463 | if (!tmp) { | |
464 | free(*ary); | |
2e566efd | 465 | closedir(dir); |
10ee5932 KZ |
466 | return -1; |
467 | } | |
468 | *ary = tmp; | |
469 | } | |
fc8b1f36 KZ |
470 | if (*ary) |
471 | (*ary)[count++] = n; | |
10ee5932 | 472 | } |
fc8b1f36 | 473 | if (count && *ary) |
10ee5932 KZ |
474 | qsort(*ary, count, sizeof(int), cmpnum); |
475 | ||
476 | closedir(dir); | |
477 | return count; | |
478 | } | |
479 | ||
e4062c72 KZ |
480 | /* |
481 | * Set the next *used* loop device according to /proc/partitions. | |
482 | * | |
483 | * Loop devices smaller than 512 bytes are invisible for this function. | |
484 | */ | |
485 | static int loopcxt_next_from_proc(struct loopdev_cxt *lc) | |
486 | { | |
487 | struct loopdev_iter *iter = &lc->iter; | |
488 | char buf[BUFSIZ]; | |
489 | ||
0bf03740 | 490 | DBG(ITER, ul_debugobj(iter, "scan /proc/partitions")); |
e4062c72 KZ |
491 | |
492 | if (!iter->proc) | |
b1fa3e22 | 493 | iter->proc = fopen(_PATH_PROC_PARTITIONS, "r" UL_CLOEXECSTR); |
e4062c72 KZ |
494 | if (!iter->proc) |
495 | return 1; | |
496 | ||
497 | while (fgets(buf, sizeof(buf), iter->proc)) { | |
498 | unsigned int m; | |
657d9adb | 499 | char name[128 + 1]; |
e4062c72 KZ |
500 | |
501 | ||
502 | if (sscanf(buf, " %u %*s %*s %128[^\n ]", | |
503 | &m, name) != 2 || m != LOOPDEV_MAJOR) | |
504 | continue; | |
505 | ||
0bf03740 | 506 | DBG(ITER, ul_debugobj(iter, "checking %s", name)); |
e4062c72 KZ |
507 | |
508 | if (loopiter_set_device(lc, name) == 0) | |
509 | return 0; | |
510 | } | |
511 | ||
512 | return 1; | |
513 | } | |
514 | ||
515 | /* | |
516 | * Set the next *used* loop device according to | |
517 | * /sys/block/loopN/loop/backing_file (kernel >= 2.6.37 is required). | |
518 | * | |
519 | * This is preferred method. | |
520 | */ | |
521 | static int loopcxt_next_from_sysfs(struct loopdev_cxt *lc) | |
522 | { | |
523 | struct loopdev_iter *iter = &lc->iter; | |
524 | struct dirent *d; | |
525 | int fd; | |
526 | ||
0bf03740 | 527 | DBG(ITER, ul_debugobj(iter, "scanning /sys/block")); |
e4062c72 KZ |
528 | |
529 | if (!iter->sysblock) | |
530 | iter->sysblock = opendir(_PATH_SYS_BLOCK); | |
531 | ||
532 | if (!iter->sysblock) | |
533 | return 1; | |
534 | ||
535 | fd = dirfd(iter->sysblock); | |
536 | ||
537 | while ((d = readdir(iter->sysblock))) { | |
538 | char name[256]; | |
539 | struct stat st; | |
540 | ||
0bf03740 | 541 | DBG(ITER, ul_debugobj(iter, "check %s", d->d_name)); |
e4062c72 KZ |
542 | |
543 | if (strcmp(d->d_name, ".") == 0 | |
544 | || strcmp(d->d_name, "..") == 0 | |
545 | || strncmp(d->d_name, "loop", 4) != 0) | |
546 | continue; | |
547 | ||
548 | snprintf(name, sizeof(name), "%s/loop/backing_file", d->d_name); | |
549 | if (fstat_at(fd, _PATH_SYS_BLOCK, name, &st, 0) != 0) | |
550 | continue; | |
551 | ||
552 | if (loopiter_set_device(lc, d->d_name) == 0) | |
553 | return 0; | |
554 | } | |
555 | ||
556 | return 1; | |
557 | } | |
558 | ||
10ee5932 KZ |
559 | /* |
560 | * @lc: context, has to initialized by loopcxt_init_iterator() | |
561 | * | |
562 | * Returns: 0 on success, -1 on error, 1 at the end of scanning. The details | |
563 | * about the current loop device are available by | |
564 | * loopcxt_get_{fd,backing_file,device,offset, ...} functions. | |
565 | */ | |
566 | int loopcxt_next(struct loopdev_cxt *lc) | |
567 | { | |
568 | struct loopdev_iter *iter; | |
569 | ||
570 | if (!lc) | |
571 | return -EINVAL; | |
aee31ddc | 572 | |
aee31ddc | 573 | |
10ee5932 KZ |
574 | iter = &lc->iter; |
575 | if (iter->done) | |
576 | return 1; | |
577 | ||
0bf03740 KZ |
578 | DBG(ITER, ul_debugobj(iter, "next")); |
579 | ||
10ee5932 KZ |
580 | /* A) Look for used loop devices in /proc/partitions ("losetup -a" only) |
581 | */ | |
582 | if (iter->flags & LOOPITER_FL_USED) { | |
e4062c72 KZ |
583 | int rc; |
584 | ||
585 | if (loopcxt_sysfs_available(lc)) | |
586 | rc = loopcxt_next_from_sysfs(lc); | |
587 | else | |
588 | rc = loopcxt_next_from_proc(lc); | |
589 | if (rc == 0) | |
590 | return 0; | |
10ee5932 KZ |
591 | goto done; |
592 | } | |
593 | ||
594 | /* B) Classic way, try first eight loop devices (default number | |
595 | * of loop devices). This is enough for 99% of all cases. | |
596 | */ | |
597 | if (iter->default_check) { | |
0bf03740 | 598 | DBG(ITER, ul_debugobj(iter, "next: default check")); |
10ee5932 KZ |
599 | for (++iter->ncur; iter->ncur < LOOPDEV_DEFAULT_NNODES; |
600 | iter->ncur++) { | |
601 | char name[16]; | |
602 | snprintf(name, sizeof(name), "loop%d", iter->ncur); | |
603 | ||
604 | if (loopiter_set_device(lc, name) == 0) | |
605 | return 0; | |
606 | } | |
607 | iter->default_check = 0; | |
608 | } | |
609 | ||
610 | /* C) the worst possibility, scan whole /dev or /dev/loop/<N> | |
611 | */ | |
612 | if (!iter->minors) { | |
0bf03740 | 613 | DBG(ITER, ul_debugobj(iter, "next: scanning /dev")); |
10ee5932 KZ |
614 | iter->nminors = (lc->flags & LOOPDEV_FL_DEVSUBDIR) ? |
615 | loop_scandir(_PATH_DEV_LOOP, &iter->minors, 0) : | |
616 | loop_scandir(_PATH_DEV, &iter->minors, 1); | |
617 | iter->ncur = -1; | |
618 | } | |
619 | for (++iter->ncur; iter->ncur < iter->nminors; iter->ncur++) { | |
620 | char name[16]; | |
621 | snprintf(name, sizeof(name), "loop%d", iter->minors[iter->ncur]); | |
622 | ||
623 | if (loopiter_set_device(lc, name) == 0) | |
624 | return 0; | |
625 | } | |
626 | done: | |
627 | loopcxt_deinit_iterator(lc); | |
628 | return 1; | |
629 | } | |
630 | ||
631 | /* | |
632 | * @device: path to device | |
633 | */ | |
634 | int is_loopdev(const char *device) | |
635 | { | |
636 | struct stat st; | |
637 | ||
638 | if (!device) | |
639 | return 0; | |
640 | ||
641 | return (stat(device, &st) == 0 && | |
642 | S_ISBLK(st.st_mode) && | |
643 | major(st.st_rdev) == LOOPDEV_MAJOR); | |
644 | } | |
645 | ||
646 | /* | |
647 | * @lc: context | |
648 | * | |
649 | * Returns result from LOOP_GET_STAT64 ioctl or NULL on error. | |
650 | */ | |
651 | struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc) | |
652 | { | |
653 | int fd; | |
654 | ||
85794fb0 KZ |
655 | if (!lc || lc->info_failed) { |
656 | errno = EINVAL; | |
10ee5932 | 657 | return NULL; |
85794fb0 KZ |
658 | } |
659 | errno = 0; | |
10ee5932 KZ |
660 | if (lc->has_info) |
661 | return &lc->info; | |
662 | ||
663 | fd = loopcxt_get_fd(lc); | |
664 | if (fd < 0) | |
665 | return NULL; | |
666 | ||
667 | if (ioctl(fd, LOOP_GET_STATUS64, &lc->info) == 0) { | |
668 | lc->has_info = 1; | |
6c224de1 | 669 | lc->info_failed = 0; |
0bf03740 | 670 | DBG(CXT, ul_debugobj(lc, "reading loop_info64 OK")); |
10ee5932 KZ |
671 | return &lc->info; |
672 | } | |
673 | ||
85794fb0 | 674 | lc->info_failed = 1; |
0bf03740 | 675 | DBG(CXT, ul_debugobj(lc, "reading loop_info64 FAILED")); |
85794fb0 | 676 | |
10ee5932 KZ |
677 | return NULL; |
678 | } | |
679 | ||
680 | /* | |
681 | * @lc: context | |
682 | * | |
683 | * Returns (allocated) string with path to the file assicieted | |
684 | * with the current loop device. | |
685 | */ | |
686 | char *loopcxt_get_backing_file(struct loopdev_cxt *lc) | |
687 | { | |
688 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
689 | char *res = NULL; | |
690 | ||
691 | if (sysfs) | |
fd7f0718 KZ |
692 | /* |
693 | * This is always preffered, the loop_info64 | |
694 | * has too small buffer for the filename. | |
695 | */ | |
10ee5932 KZ |
696 | res = sysfs_strdup(sysfs, "loop/backing_file"); |
697 | ||
698 | if (!res && loopcxt_ioctl_enabled(lc)) { | |
699 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
700 | ||
701 | if (lo) { | |
702 | lo->lo_file_name[LO_NAME_SIZE - 2] = '*'; | |
703 | lo->lo_file_name[LO_NAME_SIZE - 1] = '\0'; | |
704 | res = strdup((char *) lo->lo_file_name); | |
705 | } | |
706 | } | |
aee31ddc | 707 | |
0bf03740 | 708 | DBG(CXT, ul_debugobj(lc, "get_backing_file [%s]", res)); |
10ee5932 KZ |
709 | return res; |
710 | } | |
711 | ||
712 | /* | |
713 | * @lc: context | |
714 | * @offset: returns offset number for the given device | |
715 | * | |
716 | * Returns: <0 on error, 0 on success | |
717 | */ | |
718 | int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset) | |
719 | { | |
720 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
721 | int rc = -EINVAL; | |
722 | ||
723 | if (sysfs) | |
724 | rc = sysfs_read_u64(sysfs, "loop/offset", offset); | |
725 | ||
726 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
727 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
728 | if (lo) { | |
729 | if (offset) | |
730 | *offset = lo->lo_offset; | |
6c224de1 | 731 | rc = 0; |
85794fb0 KZ |
732 | } else |
733 | rc = -errno; | |
10ee5932 KZ |
734 | } |
735 | ||
0bf03740 | 736 | DBG(CXT, ul_debugobj(lc, "get_offset [rc=%d]", rc)); |
10ee5932 KZ |
737 | return rc; |
738 | } | |
739 | ||
740 | /* | |
741 | * @lc: context | |
742 | * @sizelimit: returns size limit for the given device | |
743 | * | |
744 | * Returns: <0 on error, 0 on success | |
745 | */ | |
746 | int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size) | |
747 | { | |
748 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
749 | int rc = -EINVAL; | |
750 | ||
751 | if (sysfs) | |
752 | rc = sysfs_read_u64(sysfs, "loop/sizelimit", size); | |
753 | ||
754 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
755 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
756 | if (lo) { | |
757 | if (size) | |
758 | *size = lo->lo_sizelimit; | |
6c224de1 | 759 | rc = 0; |
85794fb0 KZ |
760 | } else |
761 | rc = -errno; | |
10ee5932 KZ |
762 | } |
763 | ||
0bf03740 | 764 | DBG(CXT, ul_debugobj(lc, "get_sizelimit [rc=%d]", rc)); |
6c224de1 KZ |
765 | return rc; |
766 | } | |
767 | ||
768 | /* | |
769 | * @lc: context | |
770 | * @devno: returns encryption type | |
771 | * | |
772 | * Cryptoloop is DEPRECATED! | |
773 | * | |
774 | * Returns: <0 on error, 0 on success | |
775 | */ | |
776 | int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type) | |
777 | { | |
778 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 779 | int rc; |
6c224de1 | 780 | |
85794fb0 | 781 | /* not provided by sysfs */ |
6c224de1 KZ |
782 | if (lo) { |
783 | if (type) | |
784 | *type = lo->lo_encrypt_type; | |
785 | rc = 0; | |
85794fb0 KZ |
786 | } else |
787 | rc = -errno; | |
788 | ||
0bf03740 | 789 | DBG(CXT, ul_debugobj(lc, "get_encrypt_type [rc=%d]", rc)); |
6c224de1 KZ |
790 | return rc; |
791 | } | |
792 | ||
793 | /* | |
794 | * @lc: context | |
795 | * @devno: returns crypt name | |
796 | * | |
797 | * Cryptoloop is DEPRECATED! | |
798 | * | |
799 | * Returns: <0 on error, 0 on success | |
800 | */ | |
801 | const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc) | |
802 | { | |
803 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
804 | ||
805 | if (lo) | |
806 | return (char *) lo->lo_crypt_name; | |
807 | ||
0bf03740 | 808 | DBG(CXT, ul_debugobj(lc, "get_crypt_name failed")); |
6c224de1 KZ |
809 | return NULL; |
810 | } | |
811 | ||
812 | /* | |
813 | * @lc: context | |
814 | * @devno: returns backing file devno | |
815 | * | |
816 | * Returns: <0 on error, 0 on success | |
817 | */ | |
818 | int loopcxt_get_backing_devno(struct loopdev_cxt *lc, dev_t *devno) | |
819 | { | |
820 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 821 | int rc; |
6c224de1 KZ |
822 | |
823 | if (lo) { | |
824 | if (devno) | |
825 | *devno = lo->lo_device; | |
826 | rc = 0; | |
85794fb0 KZ |
827 | } else |
828 | rc = -errno; | |
829 | ||
0bf03740 | 830 | DBG(CXT, ul_debugobj(lc, "get_backing_devno [rc=%d]", rc)); |
6c224de1 KZ |
831 | return rc; |
832 | } | |
833 | ||
834 | /* | |
835 | * @lc: context | |
836 | * @ino: returns backing file inode | |
837 | * | |
838 | * Returns: <0 on error, 0 on success | |
839 | */ | |
840 | int loopcxt_get_backing_inode(struct loopdev_cxt *lc, ino_t *ino) | |
841 | { | |
842 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 843 | int rc; |
6c224de1 KZ |
844 | |
845 | if (lo) { | |
846 | if (ino) | |
847 | *ino = lo->lo_inode; | |
848 | rc = 0; | |
85794fb0 KZ |
849 | } else |
850 | rc = -errno; | |
851 | ||
0bf03740 | 852 | DBG(CXT, ul_debugobj(lc, "get_backing_inode [rc=%d]", rc)); |
10ee5932 KZ |
853 | return rc; |
854 | } | |
855 | ||
59d749c3 KZ |
856 | /* |
857 | * Check if the kernel supports partitioned loop devices. | |
858 | * | |
859 | * Notes: | |
860 | * - kernels < 3.2 support partitioned loop devices and PT scanning | |
861 | * only if max_part= module paremeter is non-zero | |
862 | * | |
863 | * - kernels >= 3.2 always support partitioned loop devices | |
864 | * | |
865 | * - kernels >= 3.2 always support BLKPG_{ADD,DEL}_PARTITION ioctls | |
866 | * | |
867 | * - kernels >= 3.2 enable PT scanner only if max_part= is non-zero or if the | |
868 | * LO_FLAGS_PARTSCAN flag is set for the device. The PT scanner is disabled | |
869 | * by default. | |
870 | * | |
871 | * See kernel commit e03c8dd14915fabc101aa495828d58598dc5af98. | |
872 | */ | |
873 | int loopmod_supports_partscan(void) | |
874 | { | |
875 | int rc, ret = 0; | |
876 | FILE *f; | |
877 | ||
878 | if (get_linux_version() >= KERNEL_VERSION(3,2,0)) | |
879 | return 1; | |
880 | ||
b1fa3e22 | 881 | f = fopen("/sys/module/loop/parameters/max_part", "r" UL_CLOEXECSTR); |
59d749c3 KZ |
882 | if (!f) |
883 | return 0; | |
884 | rc = fscanf(f, "%d", &ret); | |
885 | fclose(f); | |
8b04761d | 886 | return rc == 1 ? ret : 0; |
59d749c3 KZ |
887 | } |
888 | ||
10ee5932 KZ |
889 | /* |
890 | * @lc: context | |
891 | * | |
59d749c3 KZ |
892 | * Returns: 1 if the partscan flags is set *or* (for old kernels) partitions |
893 | * scannig is enabled for all loop devices. | |
894 | */ | |
895 | int loopcxt_is_partscan(struct loopdev_cxt *lc) | |
896 | { | |
897 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
898 | ||
899 | if (sysfs) { | |
900 | /* kernel >= 3.2 */ | |
901 | int fl; | |
902 | if (sysfs_read_int(sysfs, "loop/partscan", &fl) == 0) | |
903 | return fl; | |
904 | } | |
905 | ||
906 | /* old kernels (including kernels without loopN/loop/<flags> directory */ | |
907 | return loopmod_supports_partscan(); | |
908 | } | |
909 | ||
910 | /* | |
911 | * @lc: context | |
912 | * | |
913 | * Returns: 1 if the autoclear flags is set. | |
10ee5932 KZ |
914 | */ |
915 | int loopcxt_is_autoclear(struct loopdev_cxt *lc) | |
916 | { | |
917 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
918 | ||
919 | if (sysfs) { | |
920 | int fl; | |
921 | if (sysfs_read_int(sysfs, "loop/autoclear", &fl) == 0) | |
922 | return fl; | |
923 | } | |
924 | ||
925 | if (loopcxt_ioctl_enabled(lc)) { | |
926 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
927 | if (lo) | |
928 | return lo->lo_flags & LO_FLAGS_AUTOCLEAR; | |
929 | } | |
930 | return 0; | |
931 | } | |
932 | ||
fd7f0718 KZ |
933 | /* |
934 | * @lc: context | |
935 | * | |
59d749c3 | 936 | * Returns: 1 if the readonly flags is set. |
fd7f0718 KZ |
937 | */ |
938 | int loopcxt_is_readonly(struct loopdev_cxt *lc) | |
939 | { | |
940 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
941 | ||
942 | if (sysfs) { | |
943 | int fl; | |
944 | if (sysfs_read_int(sysfs, "ro", &fl) == 0) | |
945 | return fl; | |
946 | } | |
947 | ||
948 | if (loopcxt_ioctl_enabled(lc)) { | |
949 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
950 | if (lo) | |
951 | return lo->lo_flags & LO_FLAGS_READ_ONLY; | |
952 | } | |
953 | return 0; | |
954 | } | |
955 | ||
6c224de1 KZ |
956 | /* |
957 | * @lc: context | |
958 | * @st: backing file stat or NULL | |
959 | * @backing_file: filename | |
960 | * @offset: offset | |
961 | * @flags: LOOPDEV_FL_OFFSET if @offset should not be ignored | |
962 | * | |
963 | * Returns 1 if the current @lc loopdev is associated with the given backing | |
964 | * file. Note that the preferred way is to use devno and inode number rather | |
965 | * than filename. The @backing_file filename is poor solution usable in case | |
966 | * that you don't have rights to call stat(). | |
967 | * | |
968 | * Don't forget that old kernels provide very restricted (in size) backing | |
969 | * filename by LOOP_GET_STAT64 ioctl only. | |
970 | */ | |
971 | int loopcxt_is_used(struct loopdev_cxt *lc, | |
972 | struct stat *st, | |
973 | const char *backing_file, | |
974 | uint64_t offset, | |
975 | int flags) | |
976 | { | |
977 | ino_t ino; | |
978 | dev_t dev; | |
979 | ||
980 | if (!lc) | |
981 | return 0; | |
982 | ||
0bf03740 | 983 | DBG(CXT, ul_debugobj(lc, "checking %s vs. %s", |
6c224de1 KZ |
984 | loopcxt_get_device(lc), |
985 | backing_file)); | |
986 | ||
987 | if (st && loopcxt_get_backing_inode(lc, &ino) == 0 && | |
988 | loopcxt_get_backing_devno(lc, &dev) == 0) { | |
989 | ||
990 | if (ino == st->st_ino && dev == st->st_dev) | |
991 | goto found; | |
992 | ||
993 | /* don't use filename if we have devno and inode */ | |
994 | return 0; | |
995 | } | |
996 | ||
997 | /* poor man's solution */ | |
998 | if (backing_file) { | |
999 | char *name = loopcxt_get_backing_file(lc); | |
1000 | int rc = name && strcmp(name, backing_file) == 0; | |
1001 | ||
1002 | free(name); | |
1003 | if (rc) | |
1004 | goto found; | |
1005 | } | |
1006 | ||
1007 | return 0; | |
1008 | found: | |
1009 | if (flags & LOOPDEV_FL_OFFSET) { | |
1010 | uint64_t off; | |
1011 | ||
1012 | return loopcxt_get_offset(lc, &off) == 0 && off == offset; | |
1013 | } | |
1014 | return 1; | |
1015 | } | |
1016 | ||
fd7f0718 KZ |
1017 | /* |
1018 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1019 | */ | |
10ee5932 KZ |
1020 | int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset) |
1021 | { | |
1022 | if (!lc) | |
1023 | return -EINVAL; | |
1024 | lc->info.lo_offset = offset; | |
aee31ddc | 1025 | |
0bf03740 | 1026 | DBG(CXT, ul_debugobj(lc, "set offset=%jd", offset)); |
10ee5932 KZ |
1027 | return 0; |
1028 | } | |
1029 | ||
fd7f0718 KZ |
1030 | /* |
1031 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1032 | */ | |
10ee5932 KZ |
1033 | int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit) |
1034 | { | |
1035 | if (!lc) | |
1036 | return -EINVAL; | |
1037 | lc->info.lo_sizelimit = sizelimit; | |
aee31ddc | 1038 | |
0bf03740 | 1039 | DBG(CXT, ul_debugobj(lc, "set sizelimit=%jd", sizelimit)); |
10ee5932 KZ |
1040 | return 0; |
1041 | } | |
1042 | ||
1043 | /* | |
1044 | * @lc: context | |
1045 | * @flags: kernel LO_FLAGS_{READ_ONLY,USE_AOPS,AUTOCLEAR} flags | |
1046 | * | |
fd7f0718 KZ |
1047 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
1048 | * | |
10ee5932 KZ |
1049 | * Returns: 0 on success, <0 on error. |
1050 | */ | |
1051 | int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags) | |
1052 | { | |
1053 | if (!lc) | |
1054 | return -EINVAL; | |
1055 | lc->info.lo_flags = flags; | |
aee31ddc | 1056 | |
0bf03740 | 1057 | DBG(CXT, ul_debugobj(lc, "set flags=%u", (unsigned) flags)); |
10ee5932 KZ |
1058 | return 0; |
1059 | } | |
1060 | ||
1061 | /* | |
1062 | * @lc: context | |
1063 | * @filename: backing file path (the path will be canonicalized) | |
1064 | * | |
fd7f0718 KZ |
1065 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
1066 | * | |
10ee5932 KZ |
1067 | * Returns: 0 on success, <0 on error. |
1068 | */ | |
1069 | int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename) | |
1070 | { | |
1071 | if (!lc) | |
1072 | return -EINVAL; | |
1073 | ||
1074 | lc->filename = canonicalize_path(filename); | |
1075 | if (!lc->filename) | |
1076 | return -errno; | |
1077 | ||
1078 | strncpy((char *)lc->info.lo_file_name, lc->filename, LO_NAME_SIZE); | |
1079 | lc->info.lo_file_name[LO_NAME_SIZE- 1] = '\0'; | |
1080 | ||
0bf03740 | 1081 | DBG(CXT, ul_debugobj(lc, "set backing file=%s", lc->info.lo_file_name)); |
10ee5932 KZ |
1082 | return 0; |
1083 | } | |
1084 | ||
293714c0 JM |
1085 | /* |
1086 | * In kernels prior to v3.9, if the offset or sizelimit options | |
1087 | * are used, the block device's size won't be synced automatically. | |
1088 | * blockdev --getsize64 and filesystems will use the backing | |
1089 | * file size until the block device has been re-opened or the | |
1090 | * LOOP_SET_CAPACITY ioctl is called to sync the sizes. | |
1091 | * | |
1092 | * Since mount -oloop uses the LO_FLAGS_AUTOCLEAR option and passes | |
1093 | * the open file descriptor to the mount system call, we need to use | |
1094 | * the ioctl. Calling losetup directly doesn't have this problem since | |
1095 | * it closes the device when it exits and whatever consumes the device | |
1096 | * next will re-open it, causing the resync. | |
1097 | */ | |
1098 | static int loopcxt_check_size(struct loopdev_cxt *lc, int file_fd) | |
1099 | { | |
1100 | uint64_t size, expected_size; | |
1101 | int dev_fd; | |
1102 | struct stat st; | |
1103 | ||
1104 | if (!lc->info.lo_offset && !lc->info.lo_sizelimit) | |
1105 | return 0; | |
1106 | ||
01307ecf | 1107 | if (fstat(file_fd, &st)) { |
0bf03740 | 1108 | DBG(CXT, ul_debugobj(lc, "failed to fstat backing file")); |
293714c0 | 1109 | return -errno; |
01307ecf | 1110 | } |
e3b6cb87 KZ |
1111 | if (S_ISBLK(st.st_mode)) { |
1112 | if (blkdev_get_size(file_fd, | |
01307ecf | 1113 | (unsigned long long *) &expected_size)) { |
0bf03740 | 1114 | DBG(CXT, ul_debugobj(lc, "failed to determine device size")); |
e3b6cb87 | 1115 | return -errno; |
01307ecf | 1116 | } |
e3b6cb87 KZ |
1117 | } else |
1118 | expected_size = st.st_size; | |
1119 | ||
1120 | if (expected_size == 0 || expected_size <= lc->info.lo_offset) { | |
0bf03740 | 1121 | DBG(CXT, ul_debugobj(lc, "failed to determine expected size")); |
e3b6cb87 KZ |
1122 | return 0; /* ignore this error */ |
1123 | } | |
293714c0 JM |
1124 | |
1125 | if (lc->info.lo_offset > 0) | |
1126 | expected_size -= lc->info.lo_offset; | |
1127 | ||
1128 | if (lc->info.lo_sizelimit > 0 && lc->info.lo_sizelimit < expected_size) | |
1129 | expected_size = lc->info.lo_sizelimit; | |
1130 | ||
1131 | dev_fd = loopcxt_get_fd(lc); | |
01307ecf | 1132 | if (dev_fd < 0) { |
0bf03740 | 1133 | DBG(CXT, ul_debugobj(lc, "failed to get loop FD")); |
293714c0 | 1134 | return -errno; |
01307ecf | 1135 | } |
293714c0 | 1136 | |
01307ecf | 1137 | if (blkdev_get_size(dev_fd, (unsigned long long *) &size)) { |
0bf03740 | 1138 | DBG(CXT, ul_debugobj(lc, "failed to determine loopdev size")); |
293714c0 | 1139 | return -errno; |
01307ecf | 1140 | } |
293714c0 | 1141 | |
a7d5202b KZ |
1142 | /* It's block device, so, align to 512-byte sectors */ |
1143 | if (expected_size % 512) { | |
0bf03740 | 1144 | DBG(CXT, ul_debugobj(lc, "expected size misaligned to 512-byte sectors")); |
a7d5202b KZ |
1145 | expected_size = (expected_size >> 9) << 9; |
1146 | } | |
1147 | ||
293714c0 | 1148 | if (expected_size != size) { |
0bf03740 | 1149 | DBG(CXT, ul_debugobj(lc, "warning: loopdev and expected " |
e3b6cb87 KZ |
1150 | "size dismatch (%ju/%ju)", |
1151 | size, expected_size)); | |
1152 | ||
293714c0 JM |
1153 | if (loopcxt_set_capacity(lc)) { |
1154 | /* ioctl not available */ | |
1155 | if (errno == ENOTTY || errno == EINVAL) | |
1156 | errno = ERANGE; | |
1157 | return -errno; | |
1158 | } | |
1159 | ||
1160 | if (blkdev_get_size(dev_fd, (unsigned long long *) &size)) | |
1161 | return -errno; | |
1162 | ||
01307ecf KZ |
1163 | if (expected_size != size) { |
1164 | errno = ERANGE; | |
0bf03740 | 1165 | DBG(CXT, ul_debugobj(lc, "failed to set loopdev size, " |
01307ecf KZ |
1166 | "size: %ju, expected: %ju", |
1167 | size, expected_size)); | |
1168 | return -errno; | |
1169 | } | |
293714c0 JM |
1170 | } |
1171 | ||
1172 | return 0; | |
1173 | } | |
1174 | ||
10ee5932 KZ |
1175 | /* |
1176 | * @cl: context | |
1177 | * | |
1178 | * Associate the current device (see loopcxt_{set,get}_device()) with | |
1179 | * a file (see loopcxt_set_backing_file()). | |
1180 | * | |
fd7f0718 KZ |
1181 | * The device is initialized read-write by default. If you want read-only |
1182 | * device then set LO_FLAGS_READ_ONLY by loopcxt_set_flags(). The LOOPDEV_FL_* | |
1183 | * flags are ignored and modified according to LO_FLAGS_*. | |
1184 | * | |
1185 | * If the device is already open by loopcxt_get_fd() then this setup device | |
1186 | * function will re-open the device to fix read/write mode. | |
1187 | * | |
1188 | * The device is also initialized read-only if the backing file is not | |
1189 | * possible to open read-write (e.g. read-only FS). | |
10ee5932 KZ |
1190 | * |
1191 | * Returns: <0 on error, 0 on success. | |
1192 | */ | |
1193 | int loopcxt_setup_device(struct loopdev_cxt *lc) | |
1194 | { | |
663bf040 | 1195 | int file_fd, dev_fd, mode = O_RDWR, rc = -1, cnt = 0; |
10ee5932 KZ |
1196 | |
1197 | if (!lc || !*lc->device || !lc->filename) | |
1198 | return -EINVAL; | |
1199 | ||
0bf03740 | 1200 | DBG(SETUP, ul_debugobj(lc, "device setup requested")); |
aee31ddc | 1201 | |
10ee5932 KZ |
1202 | /* |
1203 | * Open backing file and device | |
1204 | */ | |
fd7f0718 KZ |
1205 | if (lc->info.lo_flags & LO_FLAGS_READ_ONLY) |
1206 | mode = O_RDONLY; | |
10ee5932 | 1207 | |
b1fa3e22 | 1208 | if ((file_fd = open(lc->filename, mode | O_CLOEXEC)) < 0) { |
10ee5932 KZ |
1209 | if (mode != O_RDONLY && (errno == EROFS || errno == EACCES)) |
1210 | file_fd = open(lc->filename, mode = O_RDONLY); | |
1211 | ||
aee31ddc | 1212 | if (file_fd < 0) { |
0bf03740 | 1213 | DBG(SETUP, ul_debugobj(lc, "open backing file failed: %m")); |
10ee5932 | 1214 | return -errno; |
aee31ddc | 1215 | } |
10ee5932 | 1216 | } |
0bf03740 | 1217 | DBG(SETUP, ul_debugobj(lc, "backing file open: OK")); |
10ee5932 | 1218 | |
fd7f0718 | 1219 | if (lc->fd != -1 && lc->mode != mode) { |
0bf03740 | 1220 | DBG(SETUP, ul_debugobj(lc, "closing already open device (mode mismatch)")); |
fd7f0718 KZ |
1221 | close(lc->fd); |
1222 | lc->fd = -1; | |
1223 | lc->mode = 0; | |
1224 | } | |
1225 | ||
10ee5932 | 1226 | if (mode == O_RDONLY) { |
fd7f0718 KZ |
1227 | lc->flags |= LOOPDEV_FL_RDONLY; /* open() mode */ |
1228 | lc->info.lo_flags |= LO_FLAGS_READ_ONLY; /* kernel loopdev mode */ | |
1229 | } else { | |
1230 | lc->flags |= LOOPDEV_FL_RDWR; /* open() mode */ | |
1231 | lc->info.lo_flags &= ~LO_FLAGS_READ_ONLY; | |
1232 | lc->flags &= ~LOOPDEV_FL_RDONLY; | |
1233 | } | |
10ee5932 | 1234 | |
663bf040 KZ |
1235 | do { |
1236 | errno = 0; | |
1237 | dev_fd = loopcxt_get_fd(lc); | |
1238 | if (dev_fd >= 0 || lc->control_ok == 0) | |
1239 | break; | |
1240 | if (errno != EACCES && errno != ENOENT) | |
1241 | break; | |
1242 | /* We have permissions to open /dev/loop-control, but open | |
1243 | * /dev/loopN failed with EACCES, it's probably because udevd | |
1244 | * does not applied chown yet. Let's wait a moment. */ | |
1245 | xusleep(25000); | |
1246 | } while (cnt++ < 16); | |
1247 | ||
10ee5932 KZ |
1248 | if (dev_fd < 0) { |
1249 | rc = -errno; | |
1250 | goto err; | |
1251 | } | |
1252 | ||
0bf03740 | 1253 | DBG(SETUP, ul_debugobj(lc, "device open: OK")); |
d356c5d2 | 1254 | |
10ee5932 KZ |
1255 | /* |
1256 | * Set FD | |
1257 | */ | |
1258 | if (ioctl(dev_fd, LOOP_SET_FD, file_fd) < 0) { | |
1259 | rc = -errno; | |
0bf03740 | 1260 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_FD failed: %m")); |
10ee5932 KZ |
1261 | goto err; |
1262 | } | |
d356c5d2 | 1263 | |
0bf03740 | 1264 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_FD: OK")); |
d356c5d2 | 1265 | |
aee31ddc | 1266 | if (ioctl(dev_fd, LOOP_SET_STATUS64, &lc->info)) { |
0bf03740 | 1267 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64 failed: %m")); |
10ee5932 | 1268 | goto err; |
aee31ddc | 1269 | } |
d356c5d2 | 1270 | |
0bf03740 | 1271 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64: OK")); |
d356c5d2 | 1272 | |
293714c0 JM |
1273 | if ((rc = loopcxt_check_size(lc, file_fd))) |
1274 | goto err; | |
1275 | ||
1276 | close(file_fd); | |
293714c0 | 1277 | |
10ee5932 KZ |
1278 | memset(&lc->info, 0, sizeof(lc->info)); |
1279 | lc->has_info = 0; | |
6c224de1 | 1280 | lc->info_failed = 0; |
10ee5932 | 1281 | |
0bf03740 | 1282 | DBG(SETUP, ul_debugobj(lc, "success [rc=0]")); |
10ee5932 KZ |
1283 | return 0; |
1284 | err: | |
1285 | if (file_fd >= 0) | |
1286 | close(file_fd); | |
f7e21185 | 1287 | if (dev_fd >= 0 && rc != -EBUSY) |
10ee5932 KZ |
1288 | ioctl(dev_fd, LOOP_CLR_FD, 0); |
1289 | ||
0bf03740 | 1290 | DBG(SETUP, ul_debugobj(lc, "failed [rc=%d]", rc)); |
10ee5932 KZ |
1291 | return rc; |
1292 | } | |
1293 | ||
293714c0 JM |
1294 | int loopcxt_set_capacity(struct loopdev_cxt *lc) |
1295 | { | |
1296 | int fd = loopcxt_get_fd(lc); | |
1297 | ||
1298 | if (fd < 0) | |
1299 | return -EINVAL; | |
1300 | ||
1301 | /* Kernels prior to v2.6.30 don't support this ioctl */ | |
1302 | if (ioctl(fd, LOOP_SET_CAPACITY, 0) < 0) { | |
1303 | int rc = -errno; | |
0bf03740 | 1304 | DBG(CXT, ul_debugobj(lc, "LOOP_SET_CAPACITY failed: %m")); |
293714c0 JM |
1305 | return rc; |
1306 | } | |
1307 | ||
0bf03740 | 1308 | DBG(CXT, ul_debugobj(lc, "capacity set")); |
293714c0 JM |
1309 | return 0; |
1310 | } | |
1311 | ||
10ee5932 KZ |
1312 | int loopcxt_delete_device(struct loopdev_cxt *lc) |
1313 | { | |
1314 | int fd = loopcxt_get_fd(lc); | |
1315 | ||
1316 | if (fd < 0) | |
1317 | return -EINVAL; | |
1318 | ||
aee31ddc | 1319 | if (ioctl(fd, LOOP_CLR_FD, 0) < 0) { |
0bf03740 | 1320 | DBG(CXT, ul_debugobj(lc, "LOOP_CLR_FD failed: %m")); |
10ee5932 | 1321 | return -errno; |
aee31ddc KZ |
1322 | } |
1323 | ||
0bf03740 | 1324 | DBG(CXT, ul_debugobj(lc, "device removed")); |
10ee5932 KZ |
1325 | return 0; |
1326 | } | |
1327 | ||
3cb2413b KZ |
1328 | int loopcxt_add_device(struct loopdev_cxt *lc) |
1329 | { | |
1330 | int rc = -EINVAL; | |
1331 | int ctl, nr = -1; | |
1332 | const char *p, *dev = loopcxt_get_device(lc); | |
1333 | ||
1334 | if (!dev) | |
1335 | goto done; | |
1336 | ||
1337 | if (!(lc->flags & LOOPDEV_FL_CONTROL)) { | |
1338 | rc = -ENOSYS; | |
1339 | goto done; | |
1340 | } | |
1341 | ||
1342 | p = strrchr(dev, '/'); | |
1343 | if (!p || (sscanf(p, "/loop%d", &nr) != 1 && sscanf(p, "/%d", &nr) != 1) | |
1344 | || nr < 0) | |
1345 | goto done; | |
1346 | ||
1347 | ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); | |
1348 | if (ctl >= 0) { | |
0bf03740 | 1349 | DBG(CXT, ul_debugobj(lc, "add_device %d", nr)); |
3cb2413b KZ |
1350 | rc = ioctl(ctl, LOOP_CTL_ADD, nr); |
1351 | close(ctl); | |
1352 | } | |
663bf040 | 1353 | lc->control_ok = rc >= 0 ? 1 : 0; |
3cb2413b | 1354 | done: |
0bf03740 | 1355 | DBG(CXT, ul_debugobj(lc, "add_device done [rc=%d]", rc)); |
3cb2413b KZ |
1356 | return rc; |
1357 | } | |
1358 | ||
59d749c3 KZ |
1359 | /* |
1360 | * Note that LOOP_CTL_GET_FREE ioctl is supported since kernel 3.1. In older | |
1361 | * kernels we have to check all loop devices to found unused one. | |
1362 | * | |
1363 | * See kernel commit 770fe30a46a12b6fb6b63fbe1737654d28e8484. | |
1364 | */ | |
10ee5932 KZ |
1365 | int loopcxt_find_unused(struct loopdev_cxt *lc) |
1366 | { | |
0b14bf7a | 1367 | int rc = -1; |
10ee5932 | 1368 | |
0bf03740 | 1369 | DBG(CXT, ul_debugobj(lc, "find_unused requested")); |
aee31ddc | 1370 | |
0b14bf7a | 1371 | if (lc->flags & LOOPDEV_FL_CONTROL) { |
b1fa3e22 | 1372 | int ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); |
10ee5932 | 1373 | |
0b14bf7a KZ |
1374 | if (ctl >= 0) |
1375 | rc = ioctl(ctl, LOOP_CTL_GET_FREE); | |
1376 | if (rc >= 0) { | |
1377 | char name[16]; | |
1378 | snprintf(name, sizeof(name), "loop%d", rc); | |
1379 | ||
1380 | rc = loopiter_set_device(lc, name); | |
1381 | } | |
663bf040 | 1382 | lc->control_ok = ctl >= 0 && rc == 0 ? 1 : 0; |
0b14bf7a KZ |
1383 | if (ctl >= 0) |
1384 | close(ctl); | |
0bf03740 | 1385 | DBG(CXT, ul_debugobj(lc, "find_unused by loop-control [rc=%d]", rc)); |
0b14bf7a KZ |
1386 | } |
1387 | ||
1388 | if (rc < 0) { | |
1389 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_FREE); | |
1390 | if (rc) | |
1391 | return rc; | |
10ee5932 | 1392 | |
0b14bf7a KZ |
1393 | rc = loopcxt_next(lc); |
1394 | loopcxt_deinit_iterator(lc); | |
0bf03740 | 1395 | DBG(CXT, ul_debugobj(lc, "find_unused by scan [rc=%d]", rc)); |
0b14bf7a | 1396 | } |
10ee5932 KZ |
1397 | return rc; |
1398 | } | |
1399 | ||
1400 | ||
1401 | ||
1402 | /* | |
1403 | * Return: TRUE/FALSE | |
1404 | */ | |
1405 | int loopdev_is_autoclear(const char *device) | |
1406 | { | |
1407 | struct loopdev_cxt lc; | |
1408 | int rc; | |
1409 | ||
1410 | if (!device) | |
1411 | return 0; | |
1412 | ||
defa0710 KZ |
1413 | rc = loopcxt_init(&lc, 0); |
1414 | if (!rc) | |
1415 | rc = loopcxt_set_device(&lc, device); | |
1416 | if (!rc) | |
1417 | rc = loopcxt_is_autoclear(&lc); | |
10ee5932 | 1418 | |
defa0710 | 1419 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1420 | return rc; |
1421 | } | |
1422 | ||
1423 | char *loopdev_get_backing_file(const char *device) | |
1424 | { | |
1425 | struct loopdev_cxt lc; | |
defa0710 | 1426 | char *res = NULL; |
10ee5932 KZ |
1427 | |
1428 | if (!device) | |
1429 | return NULL; | |
defa0710 KZ |
1430 | if (loopcxt_init(&lc, 0)) |
1431 | return NULL; | |
1432 | if (loopcxt_set_device(&lc, device) == 0) | |
1433 | res = loopcxt_get_backing_file(&lc); | |
10ee5932 | 1434 | |
10ee5932 | 1435 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1436 | return res; |
1437 | } | |
1438 | ||
1439 | /* | |
1440 | * Returns: TRUE/FALSE | |
1441 | */ | |
1442 | int loopdev_is_used(const char *device, const char *filename, | |
1443 | uint64_t offset, int flags) | |
1444 | { | |
1445 | struct loopdev_cxt lc; | |
6c224de1 | 1446 | struct stat st; |
10ee5932 KZ |
1447 | int rc = 0; |
1448 | ||
8b470b20 | 1449 | if (!device || !filename) |
10ee5932 KZ |
1450 | return 0; |
1451 | ||
defa0710 KZ |
1452 | rc = loopcxt_init(&lc, 0); |
1453 | if (!rc) | |
1454 | rc = loopcxt_set_device(&lc, device); | |
1455 | if (rc) | |
1456 | return rc; | |
10ee5932 | 1457 | |
6c224de1 KZ |
1458 | rc = !stat(filename, &st); |
1459 | rc = loopcxt_is_used(&lc, rc ? &st : NULL, filename, offset, flags); | |
10ee5932 | 1460 | |
10ee5932 | 1461 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1462 | return rc; |
1463 | } | |
1464 | ||
1465 | int loopdev_delete(const char *device) | |
1466 | { | |
1467 | struct loopdev_cxt lc; | |
1468 | int rc; | |
1469 | ||
8b470b20 KZ |
1470 | if (!device) |
1471 | return -EINVAL; | |
1472 | ||
defa0710 KZ |
1473 | rc = loopcxt_init(&lc, 0); |
1474 | if (!rc) | |
1475 | rc = loopcxt_set_device(&lc, device); | |
10ee5932 KZ |
1476 | if (!rc) |
1477 | rc = loopcxt_delete_device(&lc); | |
1478 | loopcxt_deinit(&lc); | |
1479 | return rc; | |
1480 | } | |
1481 | ||
1482 | /* | |
1483 | * Returns: 0 = success, < 0 error, 1 not found | |
1484 | */ | |
1485 | int loopcxt_find_by_backing_file(struct loopdev_cxt *lc, const char *filename, | |
1486 | uint64_t offset, int flags) | |
1487 | { | |
6c224de1 KZ |
1488 | int rc, hasst; |
1489 | struct stat st; | |
10ee5932 KZ |
1490 | |
1491 | if (!filename) | |
1492 | return -EINVAL; | |
1493 | ||
6c224de1 KZ |
1494 | hasst = !stat(filename, &st); |
1495 | ||
10ee5932 KZ |
1496 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); |
1497 | if (rc) | |
1498 | return rc; | |
1499 | ||
6c224de1 | 1500 | while ((rc = loopcxt_next(lc)) == 0) { |
10ee5932 | 1501 | |
6c224de1 KZ |
1502 | if (loopcxt_is_used(lc, hasst ? &st : NULL, |
1503 | filename, offset, flags)) | |
1504 | break; | |
10ee5932 KZ |
1505 | } |
1506 | ||
1507 | loopcxt_deinit_iterator(lc); | |
1508 | return rc; | |
1509 | } | |
1510 | ||
1511 | /* | |
1512 | * Returns allocated string with device name | |
1513 | */ | |
1514 | char *loopdev_find_by_backing_file(const char *filename, uint64_t offset, int flags) | |
1515 | { | |
1516 | struct loopdev_cxt lc; | |
1517 | char *res = NULL; | |
1518 | ||
1519 | if (!filename) | |
1520 | return NULL; | |
1521 | ||
defa0710 KZ |
1522 | if (loopcxt_init(&lc, 0)) |
1523 | return NULL; | |
06f588f7 | 1524 | if (loopcxt_find_by_backing_file(&lc, filename, offset, flags) == 0) |
10ee5932 KZ |
1525 | res = loopcxt_strdup_device(&lc); |
1526 | loopcxt_deinit(&lc); | |
1527 | ||
1528 | return res; | |
1529 | } | |
1530 | ||
d5688130 KZ |
1531 | /* |
1532 | * Returns number of loop devices associated with @file, if only one loop | |
1533 | * device is associeted with the given @filename and @loopdev is not NULL then | |
1534 | * @loopdev returns name of the device. | |
1535 | */ | |
1536 | int loopdev_count_by_backing_file(const char *filename, char **loopdev) | |
1537 | { | |
1538 | struct loopdev_cxt lc; | |
defa0710 | 1539 | int count = 0, rc; |
d5688130 KZ |
1540 | |
1541 | if (!filename) | |
1542 | return -1; | |
1543 | ||
defa0710 KZ |
1544 | rc = loopcxt_init(&lc, 0); |
1545 | if (rc) | |
1546 | return rc; | |
d5688130 KZ |
1547 | if (loopcxt_init_iterator(&lc, LOOPITER_FL_USED)) |
1548 | return -1; | |
1549 | ||
1550 | while(loopcxt_next(&lc) == 0) { | |
1551 | char *backing = loopcxt_get_backing_file(&lc); | |
1552 | ||
1553 | if (!backing || strcmp(backing, filename)) { | |
1554 | free(backing); | |
1555 | continue; | |
1556 | } | |
1557 | ||
1558 | free(backing); | |
1559 | if (loopdev && count == 0) | |
1560 | *loopdev = loopcxt_strdup_device(&lc); | |
1561 | count++; | |
1562 | } | |
1563 | ||
1564 | loopcxt_deinit(&lc); | |
1565 | ||
1566 | if (loopdev && count > 1) { | |
1567 | free(*loopdev); | |
1568 | *loopdev = NULL; | |
1569 | } | |
1570 | return count; | |
1571 | } | |
1572 |