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Commit | Line | Data |
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c444a71b | 1 | |
10ee5932 | 2 | /* |
0f23ee0c KZ |
3 | * No copyright is claimed. This code is in the public domain; do with |
4 | * it what you wish. | |
5 | * | |
6 | * Written by Karel Zak <kzak@redhat.com> | |
10ee5932 KZ |
7 | * |
8 | * -- based on mount/losetup.c | |
9 | * | |
10 | * Simple library for work with loop devices. | |
11 | * | |
12 | * - requires kernel 2.6.x | |
13 | * - reads info from /sys/block/loop<N>/loop/<attr> (new kernels) | |
14 | * - reads info by ioctl | |
15 | * - supports *unlimited* number of loop devices | |
16 | * - supports /dev/loop<N> as well as /dev/loop/<N> | |
17 | * - minimize overhead (fd, loopinfo, ... are shared for all operations) | |
18 | * - setup (associate device and backing file) | |
19 | * - delete (dis-associate file) | |
20 | * - old LOOP_{SET,GET}_STATUS (32bit) ioctls are unsupported | |
21 | * - extendible | |
22 | */ | |
23 | #include <stdio.h> | |
24 | #include <stdint.h> | |
25 | #include <string.h> | |
26 | #include <ctype.h> | |
27 | #include <fcntl.h> | |
10ee5932 KZ |
28 | #include <stdlib.h> |
29 | #include <unistd.h> | |
30 | #include <sys/ioctl.h> | |
31 | #include <sys/stat.h> | |
32 | #include <sys/mman.h> | |
10ee5932 KZ |
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" | |
293714c0 | 43 | #include "blkdev.h" |
0bf03740 | 44 | #include "debug.h" |
10ee5932 | 45 | |
0bf03740 KZ |
46 | /* |
47 | * Debug stuff (based on include/debug.h) | |
48 | */ | |
2ba641e5 | 49 | static UL_DEBUG_DEFINE_MASK(loopdev); |
0bf03740 | 50 | UL_DEBUG_DEFINE_MASKNAMES(loopdev) = UL_DEBUG_EMPTY_MASKNAMES; |
aee31ddc | 51 | |
0bf03740 KZ |
52 | #define LOOPDEV_DEBUG_INIT (1 << 1) |
53 | #define LOOPDEV_DEBUG_CXT (1 << 2) | |
54 | #define LOOPDEV_DEBUG_ITER (1 << 3) | |
55 | #define LOOPDEV_DEBUG_SETUP (1 << 4) | |
56 | #define SFDISKPROG_DEBUG_ALL 0xFFFF | |
aee31ddc | 57 | |
0bf03740 KZ |
58 | #define DBG(m, x) __UL_DBG(loopdev, LOOPDEV_DEBUG_, m, x) |
59 | #define ON_DBG(m, x) __UL_DBG_CALL(loopdev, LOOPDEV_DEBUG_, m, x) | |
aee31ddc | 60 | |
0bf03740 | 61 | static void loopdev_init_debug(void) |
aee31ddc | 62 | { |
0bf03740 KZ |
63 | if (loopdev_debug_mask) |
64 | return; | |
65 | __UL_INIT_DEBUG(loopdev, LOOPDEV_DEBUG_, 0, LOOPDEV_DEBUG); | |
aee31ddc KZ |
66 | } |
67 | ||
e4062c72 KZ |
68 | /* |
69 | * see loopcxt_init() | |
70 | */ | |
10ee5932 | 71 | #define loopcxt_ioctl_enabled(_lc) (!((_lc)->flags & LOOPDEV_FL_NOIOCTL)) |
e4062c72 KZ |
72 | #define loopcxt_sysfs_available(_lc) (!((_lc)->flags & LOOPDEV_FL_NOSYSFS)) \ |
73 | && !loopcxt_ioctl_enabled(_lc) | |
10ee5932 KZ |
74 | |
75 | /* | |
76 | * @lc: context | |
77 | * @device: device name, absolute device path or NULL to reset the current setting | |
78 | * | |
79 | * Sets device, absolute paths (e.g. "/dev/loop<N>") are unchanged, device | |
80 | * names ("loop<N>") are converted to the path (/dev/loop<N> or to | |
81 | * /dev/loop/<N>) | |
82 | * | |
85794fb0 KZ |
83 | * This sets the device name, but does not check if the device exists! |
84 | * | |
10ee5932 KZ |
85 | * Returns: <0 on error, 0 on success |
86 | */ | |
87 | int loopcxt_set_device(struct loopdev_cxt *lc, const char *device) | |
88 | { | |
89 | if (!lc) | |
90 | return -EINVAL; | |
91 | ||
f4bf9592 | 92 | if (lc->fd >= 0) { |
10ee5932 | 93 | close(lc->fd); |
0bf03740 | 94 | DBG(CXT, ul_debugobj(lc, "closing old open fd")); |
f4bf9592 | 95 | } |
10ee5932 | 96 | lc->fd = -1; |
fd7f0718 | 97 | lc->mode = 0; |
10ee5932 | 98 | lc->has_info = 0; |
6c224de1 | 99 | lc->info_failed = 0; |
10ee5932 | 100 | *lc->device = '\0'; |
fd7f0718 | 101 | memset(&lc->info, 0, sizeof(lc->info)); |
10ee5932 KZ |
102 | |
103 | /* set new */ | |
104 | if (device) { | |
105 | if (*device != '/') { | |
106 | const char *dir = _PATH_DEV; | |
107 | ||
108 | /* compose device name for /dev/loop<n> or /dev/loop/<n> */ | |
109 | if (lc->flags & LOOPDEV_FL_DEVSUBDIR) { | |
110 | if (strlen(device) < 5) | |
111 | return -1; | |
112 | device += 4; | |
113 | dir = _PATH_DEV_LOOP "/"; /* _PATH_DEV uses tailing slash */ | |
114 | } | |
115 | snprintf(lc->device, sizeof(lc->device), "%s%s", | |
116 | dir, device); | |
117 | } else { | |
118 | strncpy(lc->device, device, sizeof(lc->device)); | |
119 | lc->device[sizeof(lc->device) - 1] = '\0'; | |
120 | } | |
0bf03740 | 121 | DBG(CXT, ul_debugobj(lc, "%s name assigned", device)); |
10ee5932 KZ |
122 | } |
123 | ||
124 | sysfs_deinit(&lc->sysfs); | |
125 | return 0; | |
126 | } | |
127 | ||
c7e0925d KZ |
128 | int loopcxt_has_device(struct loopdev_cxt *lc) |
129 | { | |
130 | return lc && *lc->device; | |
131 | } | |
132 | ||
10ee5932 KZ |
133 | /* |
134 | * @lc: context | |
135 | * @flags: LOOPDEV_FL_* flags | |
136 | * | |
3fd1f771 | 137 | * Initialize loop handler. |
10ee5932 | 138 | * |
fd7f0718 KZ |
139 | * We have two sets of the flags: |
140 | * | |
141 | * * LOOPDEV_FL_* flags control loopcxt_* API behavior | |
142 | * | |
143 | * * LO_FLAGS_* are kernel flags used for LOOP_{SET,GET}_STAT64 ioctls | |
144 | * | |
145 | * Note about LOOPDEV_FL_{RDONLY,RDWR} flags. These flags are used for open(2) | |
146 | * syscall to open loop device. By default is the device open read-only. | |
147 | * | |
148 | * The expection is loopcxt_setup_device(), where the device is open read-write | |
149 | * if LO_FLAGS_READ_ONLY flags is not set (see loopcxt_set_flags()). | |
150 | * | |
10ee5932 KZ |
151 | * Returns: <0 on error, 0 on success. |
152 | */ | |
153 | int loopcxt_init(struct loopdev_cxt *lc, int flags) | |
154 | { | |
defa0710 | 155 | int rc; |
0b14bf7a | 156 | struct stat st; |
6219c25e | 157 | struct loopdev_cxt dummy = UL_LOOPDEVCXT_EMPTY; |
0b14bf7a | 158 | |
10ee5932 KZ |
159 | if (!lc) |
160 | return -EINVAL; | |
161 | ||
0bf03740 KZ |
162 | loopdev_init_debug(); |
163 | DBG(CXT, ul_debugobj(lc, "initialize context")); | |
164 | ||
6219c25e | 165 | memcpy(lc, &dummy, sizeof(dummy)); |
10ee5932 | 166 | lc->flags = flags; |
defa0710 KZ |
167 | |
168 | rc = loopcxt_set_device(lc, NULL); | |
169 | if (rc) | |
170 | return rc; | |
10ee5932 | 171 | |
df0f2ad7 KZ |
172 | if (stat(_PATH_SYS_BLOCK, &st) || !S_ISDIR(st.st_mode)) { |
173 | lc->flags |= LOOPDEV_FL_NOSYSFS; | |
174 | lc->flags &= ~LOOPDEV_FL_NOIOCTL; | |
0bf03740 | 175 | DBG(CXT, ul_debugobj(lc, "init: disable /sys usage")); |
df0f2ad7 KZ |
176 | } |
177 | ||
82b4082e | 178 | if (!(lc->flags & LOOPDEV_FL_NOSYSFS) && |
f4bf9592 | 179 | get_linux_version() >= KERNEL_VERSION(2,6,37)) { |
10ee5932 KZ |
180 | /* |
181 | * Use only sysfs for basic information about loop devices | |
182 | */ | |
183 | lc->flags |= LOOPDEV_FL_NOIOCTL; | |
0bf03740 | 184 | DBG(CXT, ul_debugobj(lc, "init: ignore ioctls")); |
f4bf9592 | 185 | } |
10ee5932 | 186 | |
f4bf9592 | 187 | if (!(lc->flags & LOOPDEV_FL_CONTROL) && !stat(_PATH_DEV_LOOPCTL, &st)) { |
0b14bf7a | 188 | lc->flags |= LOOPDEV_FL_CONTROL; |
0bf03740 | 189 | DBG(CXT, ul_debugobj(lc, "init: loop-control detected ")); |
f4bf9592 | 190 | } |
0b14bf7a | 191 | |
10ee5932 KZ |
192 | return 0; |
193 | } | |
194 | ||
195 | /* | |
196 | * @lc: context | |
197 | * | |
198 | * Deinitialize loop context | |
199 | */ | |
200 | void loopcxt_deinit(struct loopdev_cxt *lc) | |
201 | { | |
82756a74 KZ |
202 | int errsv = errno; |
203 | ||
10ee5932 KZ |
204 | if (!lc) |
205 | return; | |
206 | ||
0bf03740 | 207 | DBG(CXT, ul_debugobj(lc, "de-initialize")); |
aee31ddc | 208 | |
10ee5932 KZ |
209 | free(lc->filename); |
210 | lc->filename = NULL; | |
211 | ||
defa0710 | 212 | ignore_result( loopcxt_set_device(lc, NULL) ); |
10ee5932 | 213 | loopcxt_deinit_iterator(lc); |
82756a74 KZ |
214 | |
215 | errno = errsv; | |
10ee5932 KZ |
216 | } |
217 | ||
218 | /* | |
219 | * @lc: context | |
220 | * | |
221 | * Returns newly allocated device path. | |
222 | */ | |
223 | char *loopcxt_strdup_device(struct loopdev_cxt *lc) | |
224 | { | |
cba69bb5 | 225 | if (!lc || !*lc->device) |
10ee5932 KZ |
226 | return NULL; |
227 | return strdup(lc->device); | |
228 | } | |
229 | ||
230 | /* | |
231 | * @lc: context | |
232 | * | |
233 | * Returns pointer device name in the @lc struct. | |
234 | */ | |
235 | const char *loopcxt_get_device(struct loopdev_cxt *lc) | |
236 | { | |
cba69bb5 | 237 | return lc && *lc->device ? lc->device : NULL; |
10ee5932 KZ |
238 | } |
239 | ||
240 | /* | |
241 | * @lc: context | |
242 | * | |
243 | * Returns pointer to the sysfs context (see lib/sysfs.c) | |
244 | */ | |
245 | struct sysfs_cxt *loopcxt_get_sysfs(struct loopdev_cxt *lc) | |
246 | { | |
247 | if (!lc || !*lc->device || (lc->flags & LOOPDEV_FL_NOSYSFS)) | |
248 | return NULL; | |
249 | ||
250 | if (!lc->sysfs.devno) { | |
251 | dev_t devno = sysfs_devname_to_devno(lc->device, NULL); | |
aee31ddc | 252 | if (!devno) { |
0bf03740 | 253 | DBG(CXT, ul_debugobj(lc, "sysfs: failed devname to devno")); |
10ee5932 | 254 | return NULL; |
aee31ddc KZ |
255 | } |
256 | if (sysfs_init(&lc->sysfs, devno, NULL)) { | |
0bf03740 | 257 | DBG(CXT, ul_debugobj(lc, "sysfs: init failed")); |
10ee5932 | 258 | return NULL; |
aee31ddc | 259 | } |
10ee5932 | 260 | } |
aee31ddc | 261 | |
10ee5932 KZ |
262 | return &lc->sysfs; |
263 | } | |
264 | ||
265 | /* | |
266 | * @lc: context | |
267 | * | |
268 | * Returns: file descriptor to the open loop device or <0 on error. The mode | |
269 | * depends on LOOPDEV_FL_{RDWR,RDONLY} context flags. Default is | |
270 | * read-only. | |
271 | */ | |
272 | int loopcxt_get_fd(struct loopdev_cxt *lc) | |
273 | { | |
274 | if (!lc || !*lc->device) | |
fd7f0718 | 275 | return -EINVAL; |
10ee5932 | 276 | |
fd7f0718 KZ |
277 | if (lc->fd < 0) { |
278 | lc->mode = lc->flags & LOOPDEV_FL_RDWR ? O_RDWR : O_RDONLY; | |
b1fa3e22 | 279 | lc->fd = open(lc->device, lc->mode | O_CLOEXEC); |
0bf03740 | 280 | DBG(CXT, ul_debugobj(lc, "open %s [%s]: %m", lc->device, |
663bf040 | 281 | lc->flags & LOOPDEV_FL_RDWR ? "rw" : "ro")); |
fd7f0718 | 282 | } |
10ee5932 KZ |
283 | return lc->fd; |
284 | } | |
285 | ||
fd7f0718 KZ |
286 | int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, int mode) |
287 | { | |
288 | if (!lc) | |
289 | return -EINVAL; | |
290 | ||
291 | lc->fd = fd; | |
292 | lc->mode = mode; | |
293 | return 0; | |
294 | } | |
295 | ||
10ee5932 KZ |
296 | /* |
297 | * @lc: context | |
298 | * @flags: LOOPITER_FL_* flags | |
299 | * | |
300 | * Iterator allows to scan list of the free or used loop devices. | |
301 | * | |
302 | * Returns: <0 on error, 0 on success | |
303 | */ | |
304 | int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags) | |
305 | { | |
306 | struct loopdev_iter *iter; | |
307 | struct stat st; | |
308 | ||
309 | if (!lc) | |
310 | return -EINVAL; | |
311 | ||
aee31ddc | 312 | |
10ee5932 | 313 | iter = &lc->iter; |
0bf03740 | 314 | DBG(ITER, ul_debugobj(iter, "initialize")); |
10ee5932 KZ |
315 | |
316 | /* always zeroize | |
317 | */ | |
318 | memset(iter, 0, sizeof(*iter)); | |
319 | iter->ncur = -1; | |
320 | iter->flags = flags; | |
321 | iter->default_check = 1; | |
322 | ||
323 | if (!lc->extra_check) { | |
324 | /* | |
325 | * Check for /dev/loop/<N> subdirectory | |
326 | */ | |
82b4082e | 327 | if (!(lc->flags & LOOPDEV_FL_DEVSUBDIR) && |
10ee5932 KZ |
328 | stat(_PATH_DEV_LOOP, &st) == 0 && S_ISDIR(st.st_mode)) |
329 | lc->flags |= LOOPDEV_FL_DEVSUBDIR; | |
330 | ||
331 | lc->extra_check = 1; | |
332 | } | |
333 | return 0; | |
334 | } | |
335 | ||
336 | /* | |
337 | * @lc: context | |
338 | * | |
339 | * Returns: <0 on error, 0 on success | |
340 | */ | |
341 | int loopcxt_deinit_iterator(struct loopdev_cxt *lc) | |
342 | { | |
7552258a | 343 | struct loopdev_iter *iter; |
10ee5932 KZ |
344 | |
345 | if (!lc) | |
346 | return -EINVAL; | |
347 | ||
348 | iter = &lc->iter; | |
0bf03740 | 349 | DBG(ITER, ul_debugobj(iter, "de-initialize")); |
10ee5932 KZ |
350 | |
351 | free(iter->minors); | |
352 | if (iter->proc) | |
353 | fclose(iter->proc); | |
e4062c72 KZ |
354 | if (iter->sysblock) |
355 | closedir(iter->sysblock); | |
9a94b634 KZ |
356 | |
357 | memset(iter, 0, sizeof(*iter)); | |
10ee5932 KZ |
358 | return 0; |
359 | } | |
360 | ||
361 | /* | |
362 | * Same as loopcxt_set_device, but also checks if the device is | |
363 | * associeted with any file. | |
364 | * | |
365 | * Returns: <0 on error, 0 on success, 1 device does not match with | |
366 | * LOOPITER_FL_{USED,FREE} flags. | |
367 | */ | |
368 | static int loopiter_set_device(struct loopdev_cxt *lc, const char *device) | |
369 | { | |
370 | int rc = loopcxt_set_device(lc, device); | |
371 | int used; | |
372 | ||
373 | if (rc) | |
374 | return rc; | |
375 | ||
376 | if (!(lc->iter.flags & LOOPITER_FL_USED) && | |
377 | !(lc->iter.flags & LOOPITER_FL_FREE)) | |
378 | return 0; /* caller does not care about device status */ | |
379 | ||
85794fb0 | 380 | if (!is_loopdev(lc->device)) { |
0bf03740 | 381 | DBG(ITER, ul_debugobj(&lc->iter, "%s does not exist", lc->device)); |
85794fb0 KZ |
382 | return -errno; |
383 | } | |
384 | ||
0bf03740 | 385 | DBG(ITER, ul_debugobj(&lc->iter, "%s exist", lc->device)); |
85794fb0 | 386 | |
10ee5932 KZ |
387 | used = loopcxt_get_offset(lc, NULL) == 0; |
388 | ||
389 | if ((lc->iter.flags & LOOPITER_FL_USED) && used) | |
390 | return 0; | |
391 | ||
392 | if ((lc->iter.flags & LOOPITER_FL_FREE) && !used) | |
393 | return 0; | |
394 | ||
0bf03740 KZ |
395 | DBG(ITER, ul_debugobj(&lc->iter, "failed to use %s device", lc->device)); |
396 | ||
defa0710 | 397 | ignore_result( loopcxt_set_device(lc, NULL) ); |
10ee5932 KZ |
398 | return 1; |
399 | } | |
400 | ||
401 | static int cmpnum(const void *p1, const void *p2) | |
402 | { | |
33487796 KZ |
403 | return (((* (int *) p1) > (* (int *) p2)) - |
404 | ((* (int *) p1) < (* (int *) p2))); | |
10ee5932 KZ |
405 | } |
406 | ||
407 | /* | |
408 | * The classic scandir() is more expensive and less portable. | |
409 | * We needn't full loop device names -- loop numbers (loop<N>) | |
410 | * are enough. | |
411 | */ | |
412 | static int loop_scandir(const char *dirname, int **ary, int hasprefix) | |
413 | { | |
414 | DIR *dir; | |
415 | struct dirent *d; | |
416 | unsigned int n, count = 0, arylen = 0; | |
417 | ||
418 | if (!dirname || !ary) | |
419 | return 0; | |
0bf03740 KZ |
420 | |
421 | DBG(ITER, ul_debug("scan dir: %s", dirname)); | |
422 | ||
10ee5932 KZ |
423 | dir = opendir(dirname); |
424 | if (!dir) | |
425 | return 0; | |
10ee5932 KZ |
426 | free(*ary); |
427 | *ary = NULL; | |
428 | ||
429 | while((d = readdir(dir))) { | |
430 | #ifdef _DIRENT_HAVE_D_TYPE | |
431 | if (d->d_type != DT_BLK && d->d_type != DT_UNKNOWN && | |
432 | d->d_type != DT_LNK) | |
433 | continue; | |
434 | #endif | |
435 | if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, "..")) | |
436 | continue; | |
437 | ||
438 | if (hasprefix) { | |
439 | /* /dev/loop<N> */ | |
440 | if (sscanf(d->d_name, "loop%u", &n) != 1) | |
441 | continue; | |
442 | } else { | |
443 | /* /dev/loop/<N> */ | |
444 | char *end = NULL; | |
445 | ||
f0fe8ab5 | 446 | errno = 0; |
10ee5932 KZ |
447 | n = strtol(d->d_name, &end, 10); |
448 | if (d->d_name == end || (end && *end) || errno) | |
449 | continue; | |
450 | } | |
451 | if (n < LOOPDEV_DEFAULT_NNODES) | |
452 | continue; /* ignore loop<0..7> */ | |
453 | ||
454 | if (count + 1 > arylen) { | |
455 | int *tmp; | |
456 | ||
457 | arylen += 1; | |
458 | ||
459 | tmp = realloc(*ary, arylen * sizeof(int)); | |
460 | if (!tmp) { | |
461 | free(*ary); | |
34f6177a | 462 | *ary = NULL; |
2e566efd | 463 | closedir(dir); |
10ee5932 KZ |
464 | return -1; |
465 | } | |
466 | *ary = tmp; | |
467 | } | |
fc8b1f36 KZ |
468 | if (*ary) |
469 | (*ary)[count++] = n; | |
10ee5932 | 470 | } |
fc8b1f36 | 471 | if (count && *ary) |
10ee5932 KZ |
472 | qsort(*ary, count, sizeof(int), cmpnum); |
473 | ||
474 | closedir(dir); | |
475 | return count; | |
476 | } | |
477 | ||
e4062c72 KZ |
478 | /* |
479 | * Set the next *used* loop device according to /proc/partitions. | |
480 | * | |
481 | * Loop devices smaller than 512 bytes are invisible for this function. | |
482 | */ | |
483 | static int loopcxt_next_from_proc(struct loopdev_cxt *lc) | |
484 | { | |
485 | struct loopdev_iter *iter = &lc->iter; | |
486 | char buf[BUFSIZ]; | |
487 | ||
0bf03740 | 488 | DBG(ITER, ul_debugobj(iter, "scan /proc/partitions")); |
e4062c72 KZ |
489 | |
490 | if (!iter->proc) | |
b1fa3e22 | 491 | iter->proc = fopen(_PATH_PROC_PARTITIONS, "r" UL_CLOEXECSTR); |
e4062c72 KZ |
492 | if (!iter->proc) |
493 | return 1; | |
494 | ||
495 | while (fgets(buf, sizeof(buf), iter->proc)) { | |
496 | unsigned int m; | |
657d9adb | 497 | char name[128 + 1]; |
e4062c72 KZ |
498 | |
499 | ||
500 | if (sscanf(buf, " %u %*s %*s %128[^\n ]", | |
501 | &m, name) != 2 || m != LOOPDEV_MAJOR) | |
502 | continue; | |
503 | ||
0bf03740 | 504 | DBG(ITER, ul_debugobj(iter, "checking %s", name)); |
e4062c72 KZ |
505 | |
506 | if (loopiter_set_device(lc, name) == 0) | |
507 | return 0; | |
508 | } | |
509 | ||
510 | return 1; | |
511 | } | |
512 | ||
513 | /* | |
514 | * Set the next *used* loop device according to | |
515 | * /sys/block/loopN/loop/backing_file (kernel >= 2.6.37 is required). | |
516 | * | |
517 | * This is preferred method. | |
518 | */ | |
519 | static int loopcxt_next_from_sysfs(struct loopdev_cxt *lc) | |
520 | { | |
521 | struct loopdev_iter *iter = &lc->iter; | |
522 | struct dirent *d; | |
523 | int fd; | |
524 | ||
0bf03740 | 525 | DBG(ITER, ul_debugobj(iter, "scanning /sys/block")); |
e4062c72 KZ |
526 | |
527 | if (!iter->sysblock) | |
528 | iter->sysblock = opendir(_PATH_SYS_BLOCK); | |
529 | ||
530 | if (!iter->sysblock) | |
531 | return 1; | |
532 | ||
533 | fd = dirfd(iter->sysblock); | |
534 | ||
535 | while ((d = readdir(iter->sysblock))) { | |
536 | char name[256]; | |
537 | struct stat st; | |
538 | ||
0bf03740 | 539 | DBG(ITER, ul_debugobj(iter, "check %s", d->d_name)); |
e4062c72 KZ |
540 | |
541 | if (strcmp(d->d_name, ".") == 0 | |
542 | || strcmp(d->d_name, "..") == 0 | |
543 | || strncmp(d->d_name, "loop", 4) != 0) | |
544 | continue; | |
545 | ||
546 | snprintf(name, sizeof(name), "%s/loop/backing_file", d->d_name); | |
2208b3cc | 547 | if (fstatat(fd, name, &st, 0) != 0) |
e4062c72 KZ |
548 | continue; |
549 | ||
550 | if (loopiter_set_device(lc, d->d_name) == 0) | |
551 | return 0; | |
552 | } | |
553 | ||
554 | return 1; | |
555 | } | |
556 | ||
10ee5932 KZ |
557 | /* |
558 | * @lc: context, has to initialized by loopcxt_init_iterator() | |
559 | * | |
560 | * Returns: 0 on success, -1 on error, 1 at the end of scanning. The details | |
561 | * about the current loop device are available by | |
562 | * loopcxt_get_{fd,backing_file,device,offset, ...} functions. | |
563 | */ | |
564 | int loopcxt_next(struct loopdev_cxt *lc) | |
565 | { | |
566 | struct loopdev_iter *iter; | |
567 | ||
568 | if (!lc) | |
569 | return -EINVAL; | |
aee31ddc | 570 | |
aee31ddc | 571 | |
10ee5932 KZ |
572 | iter = &lc->iter; |
573 | if (iter->done) | |
574 | return 1; | |
575 | ||
0bf03740 KZ |
576 | DBG(ITER, ul_debugobj(iter, "next")); |
577 | ||
10ee5932 KZ |
578 | /* A) Look for used loop devices in /proc/partitions ("losetup -a" only) |
579 | */ | |
580 | if (iter->flags & LOOPITER_FL_USED) { | |
e4062c72 KZ |
581 | int rc; |
582 | ||
583 | if (loopcxt_sysfs_available(lc)) | |
584 | rc = loopcxt_next_from_sysfs(lc); | |
585 | else | |
586 | rc = loopcxt_next_from_proc(lc); | |
587 | if (rc == 0) | |
588 | return 0; | |
10ee5932 KZ |
589 | goto done; |
590 | } | |
591 | ||
592 | /* B) Classic way, try first eight loop devices (default number | |
593 | * of loop devices). This is enough for 99% of all cases. | |
594 | */ | |
595 | if (iter->default_check) { | |
0bf03740 | 596 | DBG(ITER, ul_debugobj(iter, "next: default check")); |
10ee5932 KZ |
597 | for (++iter->ncur; iter->ncur < LOOPDEV_DEFAULT_NNODES; |
598 | iter->ncur++) { | |
599 | char name[16]; | |
600 | snprintf(name, sizeof(name), "loop%d", iter->ncur); | |
601 | ||
602 | if (loopiter_set_device(lc, name) == 0) | |
603 | return 0; | |
604 | } | |
605 | iter->default_check = 0; | |
606 | } | |
607 | ||
608 | /* C) the worst possibility, scan whole /dev or /dev/loop/<N> | |
609 | */ | |
610 | if (!iter->minors) { | |
0bf03740 | 611 | DBG(ITER, ul_debugobj(iter, "next: scanning /dev")); |
10ee5932 KZ |
612 | iter->nminors = (lc->flags & LOOPDEV_FL_DEVSUBDIR) ? |
613 | loop_scandir(_PATH_DEV_LOOP, &iter->minors, 0) : | |
614 | loop_scandir(_PATH_DEV, &iter->minors, 1); | |
615 | iter->ncur = -1; | |
616 | } | |
617 | for (++iter->ncur; iter->ncur < iter->nminors; iter->ncur++) { | |
618 | char name[16]; | |
619 | snprintf(name, sizeof(name), "loop%d", iter->minors[iter->ncur]); | |
620 | ||
621 | if (loopiter_set_device(lc, name) == 0) | |
622 | return 0; | |
623 | } | |
624 | done: | |
625 | loopcxt_deinit_iterator(lc); | |
626 | return 1; | |
627 | } | |
628 | ||
629 | /* | |
630 | * @device: path to device | |
631 | */ | |
632 | int is_loopdev(const char *device) | |
633 | { | |
634 | struct stat st; | |
635 | ||
cb129d9c | 636 | if (device && stat(device, &st) == 0 && |
10ee5932 | 637 | S_ISBLK(st.st_mode) && |
cb129d9c TS |
638 | major(st.st_rdev) == LOOPDEV_MAJOR) |
639 | return 1; | |
640 | ||
641 | errno = ENODEV; | |
642 | return 0; | |
10ee5932 KZ |
643 | } |
644 | ||
645 | /* | |
646 | * @lc: context | |
647 | * | |
648 | * Returns result from LOOP_GET_STAT64 ioctl or NULL on error. | |
649 | */ | |
650 | struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc) | |
651 | { | |
652 | int fd; | |
653 | ||
85794fb0 KZ |
654 | if (!lc || lc->info_failed) { |
655 | errno = EINVAL; | |
10ee5932 | 656 | return NULL; |
85794fb0 KZ |
657 | } |
658 | errno = 0; | |
10ee5932 KZ |
659 | if (lc->has_info) |
660 | return &lc->info; | |
661 | ||
662 | fd = loopcxt_get_fd(lc); | |
663 | if (fd < 0) | |
664 | return NULL; | |
665 | ||
666 | if (ioctl(fd, LOOP_GET_STATUS64, &lc->info) == 0) { | |
667 | lc->has_info = 1; | |
6c224de1 | 668 | lc->info_failed = 0; |
0bf03740 | 669 | DBG(CXT, ul_debugobj(lc, "reading loop_info64 OK")); |
10ee5932 KZ |
670 | return &lc->info; |
671 | } | |
672 | ||
85794fb0 | 673 | lc->info_failed = 1; |
0bf03740 | 674 | DBG(CXT, ul_debugobj(lc, "reading loop_info64 FAILED")); |
85794fb0 | 675 | |
10ee5932 KZ |
676 | return NULL; |
677 | } | |
678 | ||
679 | /* | |
680 | * @lc: context | |
681 | * | |
682 | * Returns (allocated) string with path to the file assicieted | |
683 | * with the current loop device. | |
684 | */ | |
685 | char *loopcxt_get_backing_file(struct loopdev_cxt *lc) | |
686 | { | |
687 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
688 | char *res = NULL; | |
689 | ||
690 | if (sysfs) | |
fd7f0718 KZ |
691 | /* |
692 | * This is always preffered, the loop_info64 | |
693 | * has too small buffer for the filename. | |
694 | */ | |
10ee5932 KZ |
695 | res = sysfs_strdup(sysfs, "loop/backing_file"); |
696 | ||
697 | if (!res && loopcxt_ioctl_enabled(lc)) { | |
698 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
699 | ||
700 | if (lo) { | |
701 | lo->lo_file_name[LO_NAME_SIZE - 2] = '*'; | |
702 | lo->lo_file_name[LO_NAME_SIZE - 1] = '\0'; | |
703 | res = strdup((char *) lo->lo_file_name); | |
704 | } | |
705 | } | |
aee31ddc | 706 | |
0bf03740 | 707 | DBG(CXT, ul_debugobj(lc, "get_backing_file [%s]", res)); |
10ee5932 KZ |
708 | return res; |
709 | } | |
710 | ||
711 | /* | |
712 | * @lc: context | |
713 | * @offset: returns offset number for the given device | |
714 | * | |
715 | * Returns: <0 on error, 0 on success | |
716 | */ | |
717 | int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset) | |
718 | { | |
719 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
720 | int rc = -EINVAL; | |
721 | ||
722 | if (sysfs) | |
723 | rc = sysfs_read_u64(sysfs, "loop/offset", offset); | |
724 | ||
725 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
726 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
727 | if (lo) { | |
728 | if (offset) | |
729 | *offset = lo->lo_offset; | |
6c224de1 | 730 | rc = 0; |
85794fb0 KZ |
731 | } else |
732 | rc = -errno; | |
10ee5932 KZ |
733 | } |
734 | ||
0bf03740 | 735 | DBG(CXT, ul_debugobj(lc, "get_offset [rc=%d]", rc)); |
10ee5932 KZ |
736 | return rc; |
737 | } | |
738 | ||
739 | /* | |
740 | * @lc: context | |
741 | * @sizelimit: returns size limit for the given device | |
742 | * | |
743 | * Returns: <0 on error, 0 on success | |
744 | */ | |
745 | int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size) | |
746 | { | |
747 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
748 | int rc = -EINVAL; | |
749 | ||
750 | if (sysfs) | |
751 | rc = sysfs_read_u64(sysfs, "loop/sizelimit", size); | |
752 | ||
753 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
754 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
755 | if (lo) { | |
756 | if (size) | |
757 | *size = lo->lo_sizelimit; | |
6c224de1 | 758 | rc = 0; |
85794fb0 KZ |
759 | } else |
760 | rc = -errno; | |
10ee5932 KZ |
761 | } |
762 | ||
0bf03740 | 763 | DBG(CXT, ul_debugobj(lc, "get_sizelimit [rc=%d]", rc)); |
6c224de1 KZ |
764 | return rc; |
765 | } | |
766 | ||
767 | /* | |
768 | * @lc: context | |
769 | * @devno: returns encryption type | |
770 | * | |
771 | * Cryptoloop is DEPRECATED! | |
772 | * | |
773 | * Returns: <0 on error, 0 on success | |
774 | */ | |
775 | int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type) | |
776 | { | |
777 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 778 | int rc; |
6c224de1 | 779 | |
85794fb0 | 780 | /* not provided by sysfs */ |
6c224de1 KZ |
781 | if (lo) { |
782 | if (type) | |
783 | *type = lo->lo_encrypt_type; | |
784 | rc = 0; | |
85794fb0 KZ |
785 | } else |
786 | rc = -errno; | |
787 | ||
0bf03740 | 788 | DBG(CXT, ul_debugobj(lc, "get_encrypt_type [rc=%d]", rc)); |
6c224de1 KZ |
789 | return rc; |
790 | } | |
791 | ||
792 | /* | |
793 | * @lc: context | |
794 | * @devno: returns crypt name | |
795 | * | |
796 | * Cryptoloop is DEPRECATED! | |
797 | * | |
798 | * Returns: <0 on error, 0 on success | |
799 | */ | |
800 | const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc) | |
801 | { | |
802 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
803 | ||
804 | if (lo) | |
805 | return (char *) lo->lo_crypt_name; | |
806 | ||
0bf03740 | 807 | DBG(CXT, ul_debugobj(lc, "get_crypt_name failed")); |
6c224de1 KZ |
808 | return NULL; |
809 | } | |
810 | ||
811 | /* | |
812 | * @lc: context | |
813 | * @devno: returns backing file devno | |
814 | * | |
815 | * Returns: <0 on error, 0 on success | |
816 | */ | |
817 | int loopcxt_get_backing_devno(struct loopdev_cxt *lc, dev_t *devno) | |
818 | { | |
819 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 820 | int rc; |
6c224de1 KZ |
821 | |
822 | if (lo) { | |
823 | if (devno) | |
824 | *devno = lo->lo_device; | |
825 | rc = 0; | |
85794fb0 KZ |
826 | } else |
827 | rc = -errno; | |
828 | ||
0bf03740 | 829 | DBG(CXT, ul_debugobj(lc, "get_backing_devno [rc=%d]", rc)); |
6c224de1 KZ |
830 | return rc; |
831 | } | |
832 | ||
833 | /* | |
834 | * @lc: context | |
835 | * @ino: returns backing file inode | |
836 | * | |
837 | * Returns: <0 on error, 0 on success | |
838 | */ | |
839 | int loopcxt_get_backing_inode(struct loopdev_cxt *lc, ino_t *ino) | |
840 | { | |
841 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 842 | int rc; |
6c224de1 KZ |
843 | |
844 | if (lo) { | |
845 | if (ino) | |
846 | *ino = lo->lo_inode; | |
847 | rc = 0; | |
85794fb0 KZ |
848 | } else |
849 | rc = -errno; | |
850 | ||
0bf03740 | 851 | DBG(CXT, ul_debugobj(lc, "get_backing_inode [rc=%d]", rc)); |
10ee5932 KZ |
852 | return rc; |
853 | } | |
854 | ||
59d749c3 KZ |
855 | /* |
856 | * Check if the kernel supports partitioned loop devices. | |
857 | * | |
858 | * Notes: | |
859 | * - kernels < 3.2 support partitioned loop devices and PT scanning | |
9e930041 | 860 | * only if max_part= module parameter is non-zero |
59d749c3 KZ |
861 | * |
862 | * - kernels >= 3.2 always support partitioned loop devices | |
863 | * | |
864 | * - kernels >= 3.2 always support BLKPG_{ADD,DEL}_PARTITION ioctls | |
865 | * | |
866 | * - kernels >= 3.2 enable PT scanner only if max_part= is non-zero or if the | |
867 | * LO_FLAGS_PARTSCAN flag is set for the device. The PT scanner is disabled | |
868 | * by default. | |
869 | * | |
870 | * See kernel commit e03c8dd14915fabc101aa495828d58598dc5af98. | |
871 | */ | |
872 | int loopmod_supports_partscan(void) | |
873 | { | |
874 | int rc, ret = 0; | |
875 | FILE *f; | |
876 | ||
877 | if (get_linux_version() >= KERNEL_VERSION(3,2,0)) | |
878 | return 1; | |
879 | ||
b1fa3e22 | 880 | f = fopen("/sys/module/loop/parameters/max_part", "r" UL_CLOEXECSTR); |
59d749c3 KZ |
881 | if (!f) |
882 | return 0; | |
883 | rc = fscanf(f, "%d", &ret); | |
884 | fclose(f); | |
8b04761d | 885 | return rc == 1 ? ret : 0; |
59d749c3 KZ |
886 | } |
887 | ||
10ee5932 KZ |
888 | /* |
889 | * @lc: context | |
890 | * | |
59d749c3 | 891 | * Returns: 1 if the partscan flags is set *or* (for old kernels) partitions |
9e930041 | 892 | * scanning is enabled for all loop devices. |
59d749c3 KZ |
893 | */ |
894 | int loopcxt_is_partscan(struct loopdev_cxt *lc) | |
895 | { | |
896 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
897 | ||
898 | if (sysfs) { | |
899 | /* kernel >= 3.2 */ | |
900 | int fl; | |
901 | if (sysfs_read_int(sysfs, "loop/partscan", &fl) == 0) | |
902 | return fl; | |
903 | } | |
904 | ||
905 | /* old kernels (including kernels without loopN/loop/<flags> directory */ | |
906 | return loopmod_supports_partscan(); | |
907 | } | |
908 | ||
909 | /* | |
910 | * @lc: context | |
911 | * | |
912 | * Returns: 1 if the autoclear flags is set. | |
10ee5932 KZ |
913 | */ |
914 | int loopcxt_is_autoclear(struct loopdev_cxt *lc) | |
915 | { | |
916 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
917 | ||
918 | if (sysfs) { | |
919 | int fl; | |
920 | if (sysfs_read_int(sysfs, "loop/autoclear", &fl) == 0) | |
921 | return fl; | |
922 | } | |
923 | ||
924 | if (loopcxt_ioctl_enabled(lc)) { | |
925 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
926 | if (lo) | |
927 | return lo->lo_flags & LO_FLAGS_AUTOCLEAR; | |
928 | } | |
929 | return 0; | |
930 | } | |
931 | ||
fd7f0718 KZ |
932 | /* |
933 | * @lc: context | |
934 | * | |
59d749c3 | 935 | * Returns: 1 if the readonly flags is set. |
fd7f0718 KZ |
936 | */ |
937 | int loopcxt_is_readonly(struct loopdev_cxt *lc) | |
938 | { | |
939 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
940 | ||
941 | if (sysfs) { | |
942 | int fl; | |
943 | if (sysfs_read_int(sysfs, "ro", &fl) == 0) | |
944 | return fl; | |
945 | } | |
946 | ||
947 | if (loopcxt_ioctl_enabled(lc)) { | |
948 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
949 | if (lo) | |
950 | return lo->lo_flags & LO_FLAGS_READ_ONLY; | |
951 | } | |
952 | return 0; | |
953 | } | |
954 | ||
faeef4d2 ML |
955 | /* |
956 | * @lc: context | |
957 | * | |
958 | * Returns: 1 if the dio flags is set. | |
959 | */ | |
960 | int loopcxt_is_dio(struct loopdev_cxt *lc) | |
961 | { | |
962 | struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); | |
963 | ||
964 | if (sysfs) { | |
965 | int fl; | |
966 | if (sysfs_read_int(sysfs, "loop/dio", &fl) == 0) | |
967 | return fl; | |
968 | } | |
969 | if (loopcxt_ioctl_enabled(lc)) { | |
970 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
971 | if (lo) | |
972 | return lo->lo_flags & LO_FLAGS_DIRECT_IO; | |
973 | } | |
974 | return 0; | |
975 | } | |
976 | ||
6c224de1 KZ |
977 | /* |
978 | * @lc: context | |
979 | * @st: backing file stat or NULL | |
980 | * @backing_file: filename | |
c444a71b KZ |
981 | * @offset: offset (use LOOPDEV_FL_OFFSET if specified) |
982 | * @sizelimit: size limit (use LOOPDEV_FL_SIZELIMIT if specified) | |
983 | * @flags: LOOPDEV_FL_{OFFSET,SIZELIMIT} | |
6c224de1 KZ |
984 | * |
985 | * Returns 1 if the current @lc loopdev is associated with the given backing | |
986 | * file. Note that the preferred way is to use devno and inode number rather | |
987 | * than filename. The @backing_file filename is poor solution usable in case | |
988 | * that you don't have rights to call stat(). | |
989 | * | |
74a4705a SB |
990 | * LOOPDEV_FL_SIZELIMIT requires LOOPDEV_FL_OFFSET being set as well. |
991 | * | |
6c224de1 KZ |
992 | * Don't forget that old kernels provide very restricted (in size) backing |
993 | * filename by LOOP_GET_STAT64 ioctl only. | |
994 | */ | |
995 | int loopcxt_is_used(struct loopdev_cxt *lc, | |
996 | struct stat *st, | |
997 | const char *backing_file, | |
998 | uint64_t offset, | |
74a4705a | 999 | uint64_t sizelimit, |
6c224de1 KZ |
1000 | int flags) |
1001 | { | |
1002 | ino_t ino; | |
1003 | dev_t dev; | |
1004 | ||
1005 | if (!lc) | |
1006 | return 0; | |
1007 | ||
0bf03740 | 1008 | DBG(CXT, ul_debugobj(lc, "checking %s vs. %s", |
6c224de1 KZ |
1009 | loopcxt_get_device(lc), |
1010 | backing_file)); | |
1011 | ||
1012 | if (st && loopcxt_get_backing_inode(lc, &ino) == 0 && | |
1013 | loopcxt_get_backing_devno(lc, &dev) == 0) { | |
1014 | ||
1015 | if (ino == st->st_ino && dev == st->st_dev) | |
1016 | goto found; | |
1017 | ||
1018 | /* don't use filename if we have devno and inode */ | |
1019 | return 0; | |
1020 | } | |
1021 | ||
1022 | /* poor man's solution */ | |
1023 | if (backing_file) { | |
1024 | char *name = loopcxt_get_backing_file(lc); | |
1025 | int rc = name && strcmp(name, backing_file) == 0; | |
1026 | ||
1027 | free(name); | |
1028 | if (rc) | |
1029 | goto found; | |
1030 | } | |
1031 | ||
1032 | return 0; | |
1033 | found: | |
1034 | if (flags & LOOPDEV_FL_OFFSET) { | |
1035 | uint64_t off; | |
1036 | ||
74a4705a SB |
1037 | int rc = loopcxt_get_offset(lc, &off) == 0 && off == offset; |
1038 | ||
1039 | if (rc && flags & LOOPDEV_FL_SIZELIMIT) { | |
1040 | uint64_t sz; | |
1041 | ||
1042 | return loopcxt_get_sizelimit(lc, &sz) == 0 && sz == sizelimit; | |
c444a71b | 1043 | } else |
74a4705a | 1044 | return rc; |
6c224de1 KZ |
1045 | } |
1046 | return 1; | |
1047 | } | |
1048 | ||
fd7f0718 KZ |
1049 | /* |
1050 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1051 | */ | |
10ee5932 KZ |
1052 | int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset) |
1053 | { | |
1054 | if (!lc) | |
1055 | return -EINVAL; | |
1056 | lc->info.lo_offset = offset; | |
aee31ddc | 1057 | |
0bf03740 | 1058 | DBG(CXT, ul_debugobj(lc, "set offset=%jd", offset)); |
10ee5932 KZ |
1059 | return 0; |
1060 | } | |
1061 | ||
fd7f0718 KZ |
1062 | /* |
1063 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1064 | */ | |
10ee5932 KZ |
1065 | int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit) |
1066 | { | |
1067 | if (!lc) | |
1068 | return -EINVAL; | |
1069 | lc->info.lo_sizelimit = sizelimit; | |
aee31ddc | 1070 | |
0bf03740 | 1071 | DBG(CXT, ul_debugobj(lc, "set sizelimit=%jd", sizelimit)); |
10ee5932 KZ |
1072 | return 0; |
1073 | } | |
1074 | ||
1075 | /* | |
1076 | * @lc: context | |
1077 | * @flags: kernel LO_FLAGS_{READ_ONLY,USE_AOPS,AUTOCLEAR} flags | |
1078 | * | |
fd7f0718 KZ |
1079 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
1080 | * | |
10ee5932 KZ |
1081 | * Returns: 0 on success, <0 on error. |
1082 | */ | |
1083 | int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags) | |
1084 | { | |
1085 | if (!lc) | |
1086 | return -EINVAL; | |
1087 | lc->info.lo_flags = flags; | |
aee31ddc | 1088 | |
0bf03740 | 1089 | DBG(CXT, ul_debugobj(lc, "set flags=%u", (unsigned) flags)); |
10ee5932 KZ |
1090 | return 0; |
1091 | } | |
1092 | ||
1093 | /* | |
1094 | * @lc: context | |
1095 | * @filename: backing file path (the path will be canonicalized) | |
1096 | * | |
fd7f0718 KZ |
1097 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
1098 | * | |
10ee5932 KZ |
1099 | * Returns: 0 on success, <0 on error. |
1100 | */ | |
1101 | int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename) | |
1102 | { | |
1103 | if (!lc) | |
1104 | return -EINVAL; | |
1105 | ||
1106 | lc->filename = canonicalize_path(filename); | |
1107 | if (!lc->filename) | |
1108 | return -errno; | |
1109 | ||
1110 | strncpy((char *)lc->info.lo_file_name, lc->filename, LO_NAME_SIZE); | |
1111 | lc->info.lo_file_name[LO_NAME_SIZE- 1] = '\0'; | |
1112 | ||
0bf03740 | 1113 | DBG(CXT, ul_debugobj(lc, "set backing file=%s", lc->info.lo_file_name)); |
10ee5932 KZ |
1114 | return 0; |
1115 | } | |
1116 | ||
293714c0 JM |
1117 | /* |
1118 | * In kernels prior to v3.9, if the offset or sizelimit options | |
1119 | * are used, the block device's size won't be synced automatically. | |
1120 | * blockdev --getsize64 and filesystems will use the backing | |
1121 | * file size until the block device has been re-opened or the | |
1122 | * LOOP_SET_CAPACITY ioctl is called to sync the sizes. | |
1123 | * | |
1124 | * Since mount -oloop uses the LO_FLAGS_AUTOCLEAR option and passes | |
1125 | * the open file descriptor to the mount system call, we need to use | |
1126 | * the ioctl. Calling losetup directly doesn't have this problem since | |
1127 | * it closes the device when it exits and whatever consumes the device | |
1128 | * next will re-open it, causing the resync. | |
1129 | */ | |
1130 | static int loopcxt_check_size(struct loopdev_cxt *lc, int file_fd) | |
1131 | { | |
1132 | uint64_t size, expected_size; | |
1133 | int dev_fd; | |
1134 | struct stat st; | |
1135 | ||
1136 | if (!lc->info.lo_offset && !lc->info.lo_sizelimit) | |
1137 | return 0; | |
1138 | ||
01307ecf | 1139 | if (fstat(file_fd, &st)) { |
0bf03740 | 1140 | DBG(CXT, ul_debugobj(lc, "failed to fstat backing file")); |
293714c0 | 1141 | return -errno; |
01307ecf | 1142 | } |
e3b6cb87 KZ |
1143 | if (S_ISBLK(st.st_mode)) { |
1144 | if (blkdev_get_size(file_fd, | |
01307ecf | 1145 | (unsigned long long *) &expected_size)) { |
0bf03740 | 1146 | DBG(CXT, ul_debugobj(lc, "failed to determine device size")); |
e3b6cb87 | 1147 | return -errno; |
01307ecf | 1148 | } |
e3b6cb87 KZ |
1149 | } else |
1150 | expected_size = st.st_size; | |
1151 | ||
1152 | if (expected_size == 0 || expected_size <= lc->info.lo_offset) { | |
0bf03740 | 1153 | DBG(CXT, ul_debugobj(lc, "failed to determine expected size")); |
e3b6cb87 KZ |
1154 | return 0; /* ignore this error */ |
1155 | } | |
293714c0 JM |
1156 | |
1157 | if (lc->info.lo_offset > 0) | |
1158 | expected_size -= lc->info.lo_offset; | |
1159 | ||
1160 | if (lc->info.lo_sizelimit > 0 && lc->info.lo_sizelimit < expected_size) | |
1161 | expected_size = lc->info.lo_sizelimit; | |
1162 | ||
1163 | dev_fd = loopcxt_get_fd(lc); | |
01307ecf | 1164 | if (dev_fd < 0) { |
0bf03740 | 1165 | DBG(CXT, ul_debugobj(lc, "failed to get loop FD")); |
293714c0 | 1166 | return -errno; |
01307ecf | 1167 | } |
293714c0 | 1168 | |
01307ecf | 1169 | if (blkdev_get_size(dev_fd, (unsigned long long *) &size)) { |
0bf03740 | 1170 | DBG(CXT, ul_debugobj(lc, "failed to determine loopdev size")); |
293714c0 | 1171 | return -errno; |
01307ecf | 1172 | } |
293714c0 | 1173 | |
a7d5202b KZ |
1174 | /* It's block device, so, align to 512-byte sectors */ |
1175 | if (expected_size % 512) { | |
0bf03740 | 1176 | DBG(CXT, ul_debugobj(lc, "expected size misaligned to 512-byte sectors")); |
a7d5202b KZ |
1177 | expected_size = (expected_size >> 9) << 9; |
1178 | } | |
1179 | ||
293714c0 | 1180 | if (expected_size != size) { |
0bf03740 | 1181 | DBG(CXT, ul_debugobj(lc, "warning: loopdev and expected " |
9e930041 | 1182 | "size mismatch (%ju/%ju)", |
e3b6cb87 KZ |
1183 | size, expected_size)); |
1184 | ||
293714c0 JM |
1185 | if (loopcxt_set_capacity(lc)) { |
1186 | /* ioctl not available */ | |
1187 | if (errno == ENOTTY || errno == EINVAL) | |
1188 | errno = ERANGE; | |
1189 | return -errno; | |
1190 | } | |
1191 | ||
1192 | if (blkdev_get_size(dev_fd, (unsigned long long *) &size)) | |
1193 | return -errno; | |
1194 | ||
01307ecf KZ |
1195 | if (expected_size != size) { |
1196 | errno = ERANGE; | |
0bf03740 | 1197 | DBG(CXT, ul_debugobj(lc, "failed to set loopdev size, " |
01307ecf KZ |
1198 | "size: %ju, expected: %ju", |
1199 | size, expected_size)); | |
1200 | return -errno; | |
1201 | } | |
293714c0 JM |
1202 | } |
1203 | ||
1204 | return 0; | |
1205 | } | |
1206 | ||
10ee5932 | 1207 | /* |
bfd4e1f7 | 1208 | * @lc: context |
10ee5932 KZ |
1209 | * |
1210 | * Associate the current device (see loopcxt_{set,get}_device()) with | |
1211 | * a file (see loopcxt_set_backing_file()). | |
1212 | * | |
fd7f0718 KZ |
1213 | * The device is initialized read-write by default. If you want read-only |
1214 | * device then set LO_FLAGS_READ_ONLY by loopcxt_set_flags(). The LOOPDEV_FL_* | |
1215 | * flags are ignored and modified according to LO_FLAGS_*. | |
1216 | * | |
1217 | * If the device is already open by loopcxt_get_fd() then this setup device | |
1218 | * function will re-open the device to fix read/write mode. | |
1219 | * | |
1220 | * The device is also initialized read-only if the backing file is not | |
1221 | * possible to open read-write (e.g. read-only FS). | |
10ee5932 KZ |
1222 | * |
1223 | * Returns: <0 on error, 0 on success. | |
1224 | */ | |
1225 | int loopcxt_setup_device(struct loopdev_cxt *lc) | |
1226 | { | |
663bf040 | 1227 | int file_fd, dev_fd, mode = O_RDWR, rc = -1, cnt = 0; |
2cde9865 | 1228 | int errsv = 0; |
10ee5932 KZ |
1229 | |
1230 | if (!lc || !*lc->device || !lc->filename) | |
1231 | return -EINVAL; | |
1232 | ||
0bf03740 | 1233 | DBG(SETUP, ul_debugobj(lc, "device setup requested")); |
aee31ddc | 1234 | |
10ee5932 KZ |
1235 | /* |
1236 | * Open backing file and device | |
1237 | */ | |
fd7f0718 KZ |
1238 | if (lc->info.lo_flags & LO_FLAGS_READ_ONLY) |
1239 | mode = O_RDONLY; | |
10ee5932 | 1240 | |
b1fa3e22 | 1241 | if ((file_fd = open(lc->filename, mode | O_CLOEXEC)) < 0) { |
10ee5932 KZ |
1242 | if (mode != O_RDONLY && (errno == EROFS || errno == EACCES)) |
1243 | file_fd = open(lc->filename, mode = O_RDONLY); | |
1244 | ||
aee31ddc | 1245 | if (file_fd < 0) { |
0bf03740 | 1246 | DBG(SETUP, ul_debugobj(lc, "open backing file failed: %m")); |
10ee5932 | 1247 | return -errno; |
aee31ddc | 1248 | } |
10ee5932 | 1249 | } |
0bf03740 | 1250 | DBG(SETUP, ul_debugobj(lc, "backing file open: OK")); |
10ee5932 | 1251 | |
fd7f0718 | 1252 | if (lc->fd != -1 && lc->mode != mode) { |
0bf03740 | 1253 | DBG(SETUP, ul_debugobj(lc, "closing already open device (mode mismatch)")); |
fd7f0718 KZ |
1254 | close(lc->fd); |
1255 | lc->fd = -1; | |
1256 | lc->mode = 0; | |
1257 | } | |
1258 | ||
10ee5932 | 1259 | if (mode == O_RDONLY) { |
fd7f0718 KZ |
1260 | lc->flags |= LOOPDEV_FL_RDONLY; /* open() mode */ |
1261 | lc->info.lo_flags |= LO_FLAGS_READ_ONLY; /* kernel loopdev mode */ | |
1262 | } else { | |
1263 | lc->flags |= LOOPDEV_FL_RDWR; /* open() mode */ | |
1264 | lc->info.lo_flags &= ~LO_FLAGS_READ_ONLY; | |
1265 | lc->flags &= ~LOOPDEV_FL_RDONLY; | |
1266 | } | |
10ee5932 | 1267 | |
663bf040 KZ |
1268 | do { |
1269 | errno = 0; | |
1270 | dev_fd = loopcxt_get_fd(lc); | |
1271 | if (dev_fd >= 0 || lc->control_ok == 0) | |
1272 | break; | |
1273 | if (errno != EACCES && errno != ENOENT) | |
1274 | break; | |
1275 | /* We have permissions to open /dev/loop-control, but open | |
1276 | * /dev/loopN failed with EACCES, it's probably because udevd | |
1277 | * does not applied chown yet. Let's wait a moment. */ | |
1278 | xusleep(25000); | |
1279 | } while (cnt++ < 16); | |
1280 | ||
10ee5932 KZ |
1281 | if (dev_fd < 0) { |
1282 | rc = -errno; | |
1283 | goto err; | |
1284 | } | |
1285 | ||
0bf03740 | 1286 | DBG(SETUP, ul_debugobj(lc, "device open: OK")); |
d356c5d2 | 1287 | |
10ee5932 KZ |
1288 | /* |
1289 | * Set FD | |
1290 | */ | |
1291 | if (ioctl(dev_fd, LOOP_SET_FD, file_fd) < 0) { | |
1292 | rc = -errno; | |
2cde9865 | 1293 | errsv = errno; |
0bf03740 | 1294 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_FD failed: %m")); |
10ee5932 KZ |
1295 | goto err; |
1296 | } | |
d356c5d2 | 1297 | |
0bf03740 | 1298 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_FD: OK")); |
d356c5d2 | 1299 | |
aee31ddc | 1300 | if (ioctl(dev_fd, LOOP_SET_STATUS64, &lc->info)) { |
2cde9865 KZ |
1301 | rc = -errno; |
1302 | errsv = errno; | |
0bf03740 | 1303 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64 failed: %m")); |
10ee5932 | 1304 | goto err; |
aee31ddc | 1305 | } |
d356c5d2 | 1306 | |
0bf03740 | 1307 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64: OK")); |
d356c5d2 | 1308 | |
293714c0 JM |
1309 | if ((rc = loopcxt_check_size(lc, file_fd))) |
1310 | goto err; | |
1311 | ||
1312 | close(file_fd); | |
293714c0 | 1313 | |
10ee5932 KZ |
1314 | memset(&lc->info, 0, sizeof(lc->info)); |
1315 | lc->has_info = 0; | |
6c224de1 | 1316 | lc->info_failed = 0; |
10ee5932 | 1317 | |
0bf03740 | 1318 | DBG(SETUP, ul_debugobj(lc, "success [rc=0]")); |
10ee5932 KZ |
1319 | return 0; |
1320 | err: | |
1321 | if (file_fd >= 0) | |
1322 | close(file_fd); | |
f7e21185 | 1323 | if (dev_fd >= 0 && rc != -EBUSY) |
10ee5932 | 1324 | ioctl(dev_fd, LOOP_CLR_FD, 0); |
2cde9865 KZ |
1325 | if (errsv) |
1326 | errno = errsv; | |
10ee5932 | 1327 | |
0bf03740 | 1328 | DBG(SETUP, ul_debugobj(lc, "failed [rc=%d]", rc)); |
10ee5932 KZ |
1329 | return rc; |
1330 | } | |
1331 | ||
bfd4e1f7 SB |
1332 | /* |
1333 | * @lc: context | |
1334 | * | |
1335 | * Update status of the current device (see loopcxt_{set,get}_device()). | |
1336 | * | |
1337 | * Note that once initialized, kernel accepts only selected changes: | |
1338 | * LO_FLAGS_AUTOCLEAR and LO_FLAGS_PARTSCAN | |
1339 | * For more see linux/drivers/block/loop.c:loop_set_status() | |
1340 | * | |
1341 | * Returns: <0 on error, 0 on success. | |
1342 | */ | |
1343 | int loopcxt_set_status(struct loopdev_cxt *lc) | |
1344 | { | |
1345 | int dev_fd, rc = -1; | |
1346 | ||
1347 | errno = 0; | |
1348 | dev_fd = loopcxt_get_fd(lc); | |
1349 | ||
1350 | if (dev_fd < 0) { | |
1351 | rc = -errno; | |
1352 | return rc; | |
1353 | } | |
1354 | DBG(SETUP, ul_debugobj(lc, "device open: OK")); | |
1355 | ||
1356 | if (ioctl(dev_fd, LOOP_SET_STATUS64, &lc->info)) { | |
1357 | rc = -errno; | |
1358 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64 failed: %m")); | |
1359 | return rc; | |
1360 | } | |
1361 | ||
1362 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64: OK")); | |
1363 | return 0; | |
1364 | } | |
1365 | ||
293714c0 JM |
1366 | int loopcxt_set_capacity(struct loopdev_cxt *lc) |
1367 | { | |
1368 | int fd = loopcxt_get_fd(lc); | |
1369 | ||
1370 | if (fd < 0) | |
1371 | return -EINVAL; | |
1372 | ||
1373 | /* Kernels prior to v2.6.30 don't support this ioctl */ | |
1374 | if (ioctl(fd, LOOP_SET_CAPACITY, 0) < 0) { | |
1375 | int rc = -errno; | |
0bf03740 | 1376 | DBG(CXT, ul_debugobj(lc, "LOOP_SET_CAPACITY failed: %m")); |
293714c0 JM |
1377 | return rc; |
1378 | } | |
1379 | ||
0bf03740 | 1380 | DBG(CXT, ul_debugobj(lc, "capacity set")); |
293714c0 JM |
1381 | return 0; |
1382 | } | |
1383 | ||
64c3bb3c ML |
1384 | int loopcxt_set_dio(struct loopdev_cxt *lc, unsigned long use_dio) |
1385 | { | |
1386 | int fd = loopcxt_get_fd(lc); | |
1387 | ||
1388 | if (fd < 0) | |
1389 | return -EINVAL; | |
1390 | ||
1391 | /* Kernels prior to v4.4 don't support this ioctl */ | |
1392 | if (ioctl(fd, LOOP_SET_DIRECT_IO, use_dio) < 0) { | |
1393 | int rc = -errno; | |
1394 | DBG(CXT, ul_debugobj(lc, "LOOP_SET_DIRECT_IO failed: %m")); | |
1395 | return rc; | |
1396 | } | |
1397 | ||
1398 | DBG(CXT, ul_debugobj(lc, "direct io set")); | |
1399 | return 0; | |
1400 | } | |
1401 | ||
10ee5932 KZ |
1402 | int loopcxt_delete_device(struct loopdev_cxt *lc) |
1403 | { | |
1404 | int fd = loopcxt_get_fd(lc); | |
1405 | ||
1406 | if (fd < 0) | |
1407 | return -EINVAL; | |
1408 | ||
aee31ddc | 1409 | if (ioctl(fd, LOOP_CLR_FD, 0) < 0) { |
0bf03740 | 1410 | DBG(CXT, ul_debugobj(lc, "LOOP_CLR_FD failed: %m")); |
10ee5932 | 1411 | return -errno; |
aee31ddc KZ |
1412 | } |
1413 | ||
0bf03740 | 1414 | DBG(CXT, ul_debugobj(lc, "device removed")); |
10ee5932 KZ |
1415 | return 0; |
1416 | } | |
1417 | ||
3cb2413b KZ |
1418 | int loopcxt_add_device(struct loopdev_cxt *lc) |
1419 | { | |
1420 | int rc = -EINVAL; | |
1421 | int ctl, nr = -1; | |
1422 | const char *p, *dev = loopcxt_get_device(lc); | |
1423 | ||
1424 | if (!dev) | |
1425 | goto done; | |
1426 | ||
1427 | if (!(lc->flags & LOOPDEV_FL_CONTROL)) { | |
1428 | rc = -ENOSYS; | |
1429 | goto done; | |
1430 | } | |
1431 | ||
1432 | p = strrchr(dev, '/'); | |
1433 | if (!p || (sscanf(p, "/loop%d", &nr) != 1 && sscanf(p, "/%d", &nr) != 1) | |
1434 | || nr < 0) | |
1435 | goto done; | |
1436 | ||
1437 | ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); | |
1438 | if (ctl >= 0) { | |
0bf03740 | 1439 | DBG(CXT, ul_debugobj(lc, "add_device %d", nr)); |
3cb2413b KZ |
1440 | rc = ioctl(ctl, LOOP_CTL_ADD, nr); |
1441 | close(ctl); | |
1442 | } | |
663bf040 | 1443 | lc->control_ok = rc >= 0 ? 1 : 0; |
3cb2413b | 1444 | done: |
0bf03740 | 1445 | DBG(CXT, ul_debugobj(lc, "add_device done [rc=%d]", rc)); |
3cb2413b KZ |
1446 | return rc; |
1447 | } | |
1448 | ||
59d749c3 KZ |
1449 | /* |
1450 | * Note that LOOP_CTL_GET_FREE ioctl is supported since kernel 3.1. In older | |
1451 | * kernels we have to check all loop devices to found unused one. | |
1452 | * | |
1453 | * See kernel commit 770fe30a46a12b6fb6b63fbe1737654d28e8484. | |
1454 | */ | |
10ee5932 KZ |
1455 | int loopcxt_find_unused(struct loopdev_cxt *lc) |
1456 | { | |
0b14bf7a | 1457 | int rc = -1; |
10ee5932 | 1458 | |
0bf03740 | 1459 | DBG(CXT, ul_debugobj(lc, "find_unused requested")); |
aee31ddc | 1460 | |
0b14bf7a | 1461 | if (lc->flags & LOOPDEV_FL_CONTROL) { |
9a94b634 KZ |
1462 | int ctl; |
1463 | ||
1464 | DBG(CXT, ul_debugobj(lc, "using loop-control")); | |
10ee5932 | 1465 | |
9a94b634 | 1466 | ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); |
0b14bf7a KZ |
1467 | if (ctl >= 0) |
1468 | rc = ioctl(ctl, LOOP_CTL_GET_FREE); | |
1469 | if (rc >= 0) { | |
1470 | char name[16]; | |
1471 | snprintf(name, sizeof(name), "loop%d", rc); | |
1472 | ||
1473 | rc = loopiter_set_device(lc, name); | |
1474 | } | |
663bf040 | 1475 | lc->control_ok = ctl >= 0 && rc == 0 ? 1 : 0; |
0b14bf7a KZ |
1476 | if (ctl >= 0) |
1477 | close(ctl); | |
0bf03740 | 1478 | DBG(CXT, ul_debugobj(lc, "find_unused by loop-control [rc=%d]", rc)); |
0b14bf7a KZ |
1479 | } |
1480 | ||
1481 | if (rc < 0) { | |
9a94b634 | 1482 | DBG(CXT, ul_debugobj(lc, "using loop scan")); |
0b14bf7a KZ |
1483 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_FREE); |
1484 | if (rc) | |
1485 | return rc; | |
10ee5932 | 1486 | |
0b14bf7a KZ |
1487 | rc = loopcxt_next(lc); |
1488 | loopcxt_deinit_iterator(lc); | |
0bf03740 | 1489 | DBG(CXT, ul_debugobj(lc, "find_unused by scan [rc=%d]", rc)); |
0b14bf7a | 1490 | } |
10ee5932 KZ |
1491 | return rc; |
1492 | } | |
1493 | ||
1494 | ||
1495 | ||
1496 | /* | |
1497 | * Return: TRUE/FALSE | |
1498 | */ | |
1499 | int loopdev_is_autoclear(const char *device) | |
1500 | { | |
1501 | struct loopdev_cxt lc; | |
1502 | int rc; | |
1503 | ||
1504 | if (!device) | |
1505 | return 0; | |
1506 | ||
defa0710 KZ |
1507 | rc = loopcxt_init(&lc, 0); |
1508 | if (!rc) | |
1509 | rc = loopcxt_set_device(&lc, device); | |
1510 | if (!rc) | |
1511 | rc = loopcxt_is_autoclear(&lc); | |
10ee5932 | 1512 | |
defa0710 | 1513 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1514 | return rc; |
1515 | } | |
1516 | ||
1517 | char *loopdev_get_backing_file(const char *device) | |
1518 | { | |
1519 | struct loopdev_cxt lc; | |
defa0710 | 1520 | char *res = NULL; |
10ee5932 KZ |
1521 | |
1522 | if (!device) | |
1523 | return NULL; | |
defa0710 KZ |
1524 | if (loopcxt_init(&lc, 0)) |
1525 | return NULL; | |
1526 | if (loopcxt_set_device(&lc, device) == 0) | |
1527 | res = loopcxt_get_backing_file(&lc); | |
10ee5932 | 1528 | |
10ee5932 | 1529 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1530 | return res; |
1531 | } | |
1532 | ||
1533 | /* | |
1534 | * Returns: TRUE/FALSE | |
1535 | */ | |
1536 | int loopdev_is_used(const char *device, const char *filename, | |
74a4705a | 1537 | uint64_t offset, uint64_t sizelimit, int flags) |
10ee5932 KZ |
1538 | { |
1539 | struct loopdev_cxt lc; | |
6c224de1 | 1540 | struct stat st; |
10ee5932 KZ |
1541 | int rc = 0; |
1542 | ||
8b470b20 | 1543 | if (!device || !filename) |
10ee5932 KZ |
1544 | return 0; |
1545 | ||
defa0710 KZ |
1546 | rc = loopcxt_init(&lc, 0); |
1547 | if (!rc) | |
1548 | rc = loopcxt_set_device(&lc, device); | |
1549 | if (rc) | |
1550 | return rc; | |
10ee5932 | 1551 | |
6c224de1 | 1552 | rc = !stat(filename, &st); |
74a4705a | 1553 | rc = loopcxt_is_used(&lc, rc ? &st : NULL, filename, offset, sizelimit, flags); |
10ee5932 | 1554 | |
10ee5932 | 1555 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1556 | return rc; |
1557 | } | |
1558 | ||
1559 | int loopdev_delete(const char *device) | |
1560 | { | |
1561 | struct loopdev_cxt lc; | |
1562 | int rc; | |
1563 | ||
8b470b20 KZ |
1564 | if (!device) |
1565 | return -EINVAL; | |
1566 | ||
defa0710 KZ |
1567 | rc = loopcxt_init(&lc, 0); |
1568 | if (!rc) | |
1569 | rc = loopcxt_set_device(&lc, device); | |
10ee5932 KZ |
1570 | if (!rc) |
1571 | rc = loopcxt_delete_device(&lc); | |
1572 | loopcxt_deinit(&lc); | |
1573 | return rc; | |
1574 | } | |
1575 | ||
1576 | /* | |
1577 | * Returns: 0 = success, < 0 error, 1 not found | |
1578 | */ | |
1579 | int loopcxt_find_by_backing_file(struct loopdev_cxt *lc, const char *filename, | |
74a4705a | 1580 | uint64_t offset, uint64_t sizelimit, int flags) |
10ee5932 | 1581 | { |
6c224de1 KZ |
1582 | int rc, hasst; |
1583 | struct stat st; | |
10ee5932 KZ |
1584 | |
1585 | if (!filename) | |
1586 | return -EINVAL; | |
1587 | ||
6c224de1 KZ |
1588 | hasst = !stat(filename, &st); |
1589 | ||
10ee5932 KZ |
1590 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); |
1591 | if (rc) | |
1592 | return rc; | |
1593 | ||
6c224de1 | 1594 | while ((rc = loopcxt_next(lc)) == 0) { |
10ee5932 | 1595 | |
6c224de1 | 1596 | if (loopcxt_is_used(lc, hasst ? &st : NULL, |
74a4705a | 1597 | filename, offset, sizelimit, flags)) |
6c224de1 | 1598 | break; |
10ee5932 KZ |
1599 | } |
1600 | ||
1601 | loopcxt_deinit_iterator(lc); | |
1602 | return rc; | |
1603 | } | |
1604 | ||
211e1d46 | 1605 | /* |
dff7e160 | 1606 | * Returns: 0 = not found, < 0 error, 1 found, 2 found full size and offset match |
211e1d46 | 1607 | */ |
c444a71b | 1608 | int loopcxt_find_overlap(struct loopdev_cxt *lc, const char *filename, |
211e1d46 SB |
1609 | uint64_t offset, uint64_t sizelimit) |
1610 | { | |
1611 | int rc, hasst; | |
1612 | struct stat st; | |
1613 | ||
1614 | if (!filename) | |
1615 | return -EINVAL; | |
1616 | ||
9a94b634 | 1617 | DBG(CXT, ul_debugobj(lc, "find_overlap requested")); |
211e1d46 SB |
1618 | hasst = !stat(filename, &st); |
1619 | ||
1620 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); | |
1621 | if (rc) | |
1622 | return rc; | |
1623 | ||
1624 | while ((rc = loopcxt_next(lc)) == 0) { | |
1625 | uint64_t lc_sizelimit, lc_offset; | |
1626 | ||
1627 | rc = loopcxt_is_used(lc, hasst ? &st : NULL, | |
1628 | filename, offset, sizelimit, 0); | |
1629 | if (!rc) | |
c444a71b | 1630 | continue; /* unused */ |
dff7e160 | 1631 | if (rc < 0) |
c444a71b KZ |
1632 | break; /* error */ |
1633 | ||
211e1d46 SB |
1634 | DBG(CXT, ul_debugobj(lc, "found %s backed by %s", |
1635 | loopcxt_get_device(lc), filename)); | |
c444a71b | 1636 | |
211e1d46 SB |
1637 | rc = loopcxt_get_offset(lc, &lc_offset); |
1638 | if (rc) { | |
1639 | DBG(CXT, ul_debugobj(lc, "failed to get offset for device %s", | |
1640 | loopcxt_get_device(lc))); | |
1641 | break; | |
1642 | } | |
1643 | rc = loopcxt_get_sizelimit(lc, &lc_sizelimit); | |
1644 | if (rc) { | |
1645 | DBG(CXT, ul_debugobj(lc, "failed to get sizelimit for device %s", | |
1646 | loopcxt_get_device(lc))); | |
1647 | break; | |
1648 | } | |
1649 | ||
dff7e160 KZ |
1650 | /* full match */ |
1651 | if (lc_sizelimit == sizelimit && lc_offset == offset) { | |
1652 | DBG(CXT, ul_debugobj(lc, "overlapping loop device %s (full match)", | |
1653 | loopcxt_get_device(lc))); | |
1654 | rc = 2; | |
1655 | goto found; | |
1656 | } | |
1657 | ||
1658 | /* overlap */ | |
211e1d46 SB |
1659 | if (lc_sizelimit != 0 && offset >= lc_offset + lc_sizelimit) |
1660 | continue; | |
1661 | if (sizelimit != 0 && offset + sizelimit <= lc_offset) | |
1662 | continue; | |
dff7e160 | 1663 | |
211e1d46 SB |
1664 | DBG(CXT, ul_debugobj(lc, "overlapping loop device %s", |
1665 | loopcxt_get_device(lc))); | |
dff7e160 KZ |
1666 | rc = 1; |
1667 | goto found; | |
211e1d46 | 1668 | } |
dff7e160 KZ |
1669 | |
1670 | if (rc == 1) | |
1671 | rc = 0; /* not found */ | |
1672 | found: | |
211e1d46 | 1673 | loopcxt_deinit_iterator(lc); |
9a94b634 | 1674 | DBG(CXT, ul_debugobj(lc, "find_overlap done [rc=%d]", rc)); |
211e1d46 SB |
1675 | return rc; |
1676 | } | |
1677 | ||
10ee5932 KZ |
1678 | /* |
1679 | * Returns allocated string with device name | |
1680 | */ | |
74a4705a | 1681 | char *loopdev_find_by_backing_file(const char *filename, uint64_t offset, uint64_t sizelimit, int flags) |
10ee5932 KZ |
1682 | { |
1683 | struct loopdev_cxt lc; | |
1684 | char *res = NULL; | |
1685 | ||
1686 | if (!filename) | |
1687 | return NULL; | |
1688 | ||
defa0710 KZ |
1689 | if (loopcxt_init(&lc, 0)) |
1690 | return NULL; | |
74a4705a | 1691 | if (loopcxt_find_by_backing_file(&lc, filename, offset, sizelimit, flags) == 0) |
10ee5932 KZ |
1692 | res = loopcxt_strdup_device(&lc); |
1693 | loopcxt_deinit(&lc); | |
1694 | ||
1695 | return res; | |
1696 | } | |
1697 | ||
d5688130 KZ |
1698 | /* |
1699 | * Returns number of loop devices associated with @file, if only one loop | |
1700 | * device is associeted with the given @filename and @loopdev is not NULL then | |
1701 | * @loopdev returns name of the device. | |
1702 | */ | |
1703 | int loopdev_count_by_backing_file(const char *filename, char **loopdev) | |
1704 | { | |
1705 | struct loopdev_cxt lc; | |
defa0710 | 1706 | int count = 0, rc; |
d5688130 KZ |
1707 | |
1708 | if (!filename) | |
1709 | return -1; | |
1710 | ||
defa0710 KZ |
1711 | rc = loopcxt_init(&lc, 0); |
1712 | if (rc) | |
1713 | return rc; | |
d5688130 KZ |
1714 | if (loopcxt_init_iterator(&lc, LOOPITER_FL_USED)) |
1715 | return -1; | |
1716 | ||
1717 | while(loopcxt_next(&lc) == 0) { | |
1718 | char *backing = loopcxt_get_backing_file(&lc); | |
1719 | ||
1720 | if (!backing || strcmp(backing, filename)) { | |
1721 | free(backing); | |
1722 | continue; | |
1723 | } | |
1724 | ||
1725 | free(backing); | |
1726 | if (loopdev && count == 0) | |
1727 | *loopdev = loopcxt_strdup_device(&lc); | |
1728 | count++; | |
1729 | } | |
1730 | ||
1731 | loopcxt_deinit(&lc); | |
1732 | ||
1733 | if (loopdev && count > 1) { | |
1734 | free(*loopdev); | |
1735 | *loopdev = NULL; | |
1736 | } | |
1737 | return count; | |
1738 | } | |
1739 |