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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> | |
10ee5932 KZ |
35 | |
36 | #include "linux_version.h" | |
37 | #include "c.h" | |
38 | #include "sysfs.h" | |
39 | #include "pathnames.h" | |
40 | #include "loopdev.h" | |
41 | #include "canonicalize.h" | |
293714c0 | 42 | #include "blkdev.h" |
0bf03740 | 43 | #include "debug.h" |
fbc2fe82 | 44 | #include "fileutils.h" |
10ee5932 | 45 | |
0ae7bb11 KZ |
46 | #define LOOPDEV_MAX_TRIES 10 |
47 | ||
0bf03740 KZ |
48 | /* |
49 | * Debug stuff (based on include/debug.h) | |
50 | */ | |
2ba641e5 | 51 | static UL_DEBUG_DEFINE_MASK(loopdev); |
0bf03740 | 52 | UL_DEBUG_DEFINE_MASKNAMES(loopdev) = UL_DEBUG_EMPTY_MASKNAMES; |
aee31ddc | 53 | |
0bf03740 KZ |
54 | #define LOOPDEV_DEBUG_INIT (1 << 1) |
55 | #define LOOPDEV_DEBUG_CXT (1 << 2) | |
56 | #define LOOPDEV_DEBUG_ITER (1 << 3) | |
57 | #define LOOPDEV_DEBUG_SETUP (1 << 4) | |
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 | |
6d00cfb2 KZ |
62 | #define UL_DEBUG_CURRENT_MASK UL_DEBUG_MASK(loopdev) |
63 | #include "debugobj.h" | |
64 | ||
0bf03740 | 65 | static void loopdev_init_debug(void) |
aee31ddc | 66 | { |
0bf03740 KZ |
67 | if (loopdev_debug_mask) |
68 | return; | |
a15dca2f | 69 | __UL_INIT_DEBUG_FROM_ENV(loopdev, LOOPDEV_DEBUG_, 0, LOOPDEV_DEBUG); |
aee31ddc KZ |
70 | } |
71 | ||
e4062c72 KZ |
72 | /* |
73 | * see loopcxt_init() | |
74 | */ | |
10ee5932 | 75 | #define loopcxt_ioctl_enabled(_lc) (!((_lc)->flags & LOOPDEV_FL_NOIOCTL)) |
e4062c72 KZ |
76 | #define loopcxt_sysfs_available(_lc) (!((_lc)->flags & LOOPDEV_FL_NOSYSFS)) \ |
77 | && !loopcxt_ioctl_enabled(_lc) | |
10ee5932 | 78 | |
9d5424c2 KZ |
79 | /* |
80 | * Calls @x and repeat on EAGAIN | |
81 | */ | |
82 | #define repeat_on_eagain(x) __extension__ ({ \ | |
83 | int _c = 0, _e; \ | |
84 | do { \ | |
85 | errno = 0; \ | |
86 | _e = x; \ | |
87 | if (_e == 0 || errno != EAGAIN) \ | |
88 | break; \ | |
89 | if (_c >= LOOPDEV_MAX_TRIES) \ | |
90 | break; \ | |
91 | xusleep(250000); \ | |
92 | _c++; \ | |
93 | } while (1); \ | |
94 | _e == 0 ? 0 : errno ? -errno : -1; \ | |
95 | }) | |
96 | ||
10ee5932 KZ |
97 | /* |
98 | * @lc: context | |
99 | * @device: device name, absolute device path or NULL to reset the current setting | |
100 | * | |
101 | * Sets device, absolute paths (e.g. "/dev/loop<N>") are unchanged, device | |
102 | * names ("loop<N>") are converted to the path (/dev/loop<N> or to | |
103 | * /dev/loop/<N>) | |
104 | * | |
85794fb0 KZ |
105 | * This sets the device name, but does not check if the device exists! |
106 | * | |
10ee5932 KZ |
107 | * Returns: <0 on error, 0 on success |
108 | */ | |
109 | int loopcxt_set_device(struct loopdev_cxt *lc, const char *device) | |
110 | { | |
111 | if (!lc) | |
112 | return -EINVAL; | |
113 | ||
f4bf9592 | 114 | if (lc->fd >= 0) { |
10ee5932 | 115 | close(lc->fd); |
0bf03740 | 116 | DBG(CXT, ul_debugobj(lc, "closing old open fd")); |
f4bf9592 | 117 | } |
10ee5932 | 118 | lc->fd = -1; |
a6ca0456 JB |
119 | lc->is_lost = 0; |
120 | lc->devno = 0; | |
ced1142d | 121 | lc->mode = O_RDONLY; |
75d239ff | 122 | lc->blocksize = 0; |
10ee5932 | 123 | lc->has_info = 0; |
6c224de1 | 124 | lc->info_failed = 0; |
10ee5932 | 125 | *lc->device = '\0'; |
d5fd456c | 126 | memset(&lc->config, 0, sizeof(lc->config)); |
10ee5932 KZ |
127 | |
128 | /* set new */ | |
129 | if (device) { | |
130 | if (*device != '/') { | |
131 | const char *dir = _PATH_DEV; | |
132 | ||
133 | /* compose device name for /dev/loop<n> or /dev/loop/<n> */ | |
134 | if (lc->flags & LOOPDEV_FL_DEVSUBDIR) { | |
135 | if (strlen(device) < 5) | |
136 | return -1; | |
137 | device += 4; | |
138 | dir = _PATH_DEV_LOOP "/"; /* _PATH_DEV uses tailing slash */ | |
139 | } | |
140 | snprintf(lc->device, sizeof(lc->device), "%s%s", | |
141 | dir, device); | |
91072cd4 KZ |
142 | } else |
143 | xstrncpy(lc->device, device, sizeof(lc->device)); | |
144 | ||
0bf03740 | 145 | DBG(CXT, ul_debugobj(lc, "%s name assigned", device)); |
10ee5932 KZ |
146 | } |
147 | ||
7604f85f KZ |
148 | ul_unref_path(lc->sysfs); |
149 | lc->sysfs = NULL; | |
10ee5932 KZ |
150 | return 0; |
151 | } | |
152 | ||
dab13032 | 153 | int loopcxt_has_device(struct loopdev_cxt *lc) |
c7e0925d KZ |
154 | { |
155 | return lc && *lc->device; | |
156 | } | |
157 | ||
a6ca0456 JB |
158 | dev_t loopcxt_get_devno(struct loopdev_cxt *lc) |
159 | { | |
160 | if (!lc || !loopcxt_has_device(lc)) | |
161 | return 0; | |
162 | if (!lc->devno) | |
163 | lc->devno = sysfs_devname_to_devno(lc->device); | |
164 | return lc->devno; | |
165 | } | |
166 | ||
167 | int loopcxt_is_lost(struct loopdev_cxt *lc) | |
168 | { | |
169 | if (!lc || !loopcxt_has_device(lc)) | |
170 | return 0; | |
171 | if (lc->is_lost) | |
172 | return 1; | |
173 | ||
174 | lc->is_lost = access(lc->device, F_OK) != 0 | |
175 | && loopcxt_get_devno(lc) != 0; | |
176 | ||
177 | return lc->is_lost; | |
178 | } | |
179 | ||
10ee5932 KZ |
180 | /* |
181 | * @lc: context | |
182 | * @flags: LOOPDEV_FL_* flags | |
183 | * | |
3fd1f771 | 184 | * Initialize loop handler. |
10ee5932 | 185 | * |
fd7f0718 KZ |
186 | * We have two sets of the flags: |
187 | * | |
188 | * * LOOPDEV_FL_* flags control loopcxt_* API behavior | |
189 | * | |
190 | * * LO_FLAGS_* are kernel flags used for LOOP_{SET,GET}_STAT64 ioctls | |
191 | * | |
10ee5932 KZ |
192 | * Returns: <0 on error, 0 on success. |
193 | */ | |
194 | int loopcxt_init(struct loopdev_cxt *lc, int flags) | |
195 | { | |
defa0710 | 196 | int rc; |
0b14bf7a | 197 | struct stat st; |
6219c25e | 198 | struct loopdev_cxt dummy = UL_LOOPDEVCXT_EMPTY; |
0b14bf7a | 199 | |
10ee5932 KZ |
200 | if (!lc) |
201 | return -EINVAL; | |
202 | ||
0bf03740 KZ |
203 | loopdev_init_debug(); |
204 | DBG(CXT, ul_debugobj(lc, "initialize context")); | |
205 | ||
6219c25e | 206 | memcpy(lc, &dummy, sizeof(dummy)); |
10ee5932 | 207 | lc->flags = flags; |
defa0710 KZ |
208 | |
209 | rc = loopcxt_set_device(lc, NULL); | |
210 | if (rc) | |
211 | return rc; | |
10ee5932 | 212 | |
df0f2ad7 KZ |
213 | if (stat(_PATH_SYS_BLOCK, &st) || !S_ISDIR(st.st_mode)) { |
214 | lc->flags |= LOOPDEV_FL_NOSYSFS; | |
215 | lc->flags &= ~LOOPDEV_FL_NOIOCTL; | |
0bf03740 | 216 | DBG(CXT, ul_debugobj(lc, "init: disable /sys usage")); |
df0f2ad7 KZ |
217 | } |
218 | ||
82b4082e | 219 | if (!(lc->flags & LOOPDEV_FL_NOSYSFS) && |
f4bf9592 | 220 | get_linux_version() >= KERNEL_VERSION(2,6,37)) { |
10ee5932 KZ |
221 | /* |
222 | * Use only sysfs for basic information about loop devices | |
223 | */ | |
224 | lc->flags |= LOOPDEV_FL_NOIOCTL; | |
0bf03740 | 225 | DBG(CXT, ul_debugobj(lc, "init: ignore ioctls")); |
f4bf9592 | 226 | } |
10ee5932 | 227 | |
f4bf9592 | 228 | if (!(lc->flags & LOOPDEV_FL_CONTROL) && !stat(_PATH_DEV_LOOPCTL, &st)) { |
0b14bf7a | 229 | lc->flags |= LOOPDEV_FL_CONTROL; |
0bf03740 | 230 | DBG(CXT, ul_debugobj(lc, "init: loop-control detected ")); |
f4bf9592 | 231 | } |
0b14bf7a | 232 | |
10ee5932 KZ |
233 | return 0; |
234 | } | |
235 | ||
236 | /* | |
237 | * @lc: context | |
238 | * | |
239 | * Deinitialize loop context | |
240 | */ | |
241 | void loopcxt_deinit(struct loopdev_cxt *lc) | |
242 | { | |
82756a74 KZ |
243 | int errsv = errno; |
244 | ||
10ee5932 KZ |
245 | if (!lc) |
246 | return; | |
247 | ||
0bf03740 | 248 | DBG(CXT, ul_debugobj(lc, "de-initialize")); |
aee31ddc | 249 | |
10ee5932 KZ |
250 | free(lc->filename); |
251 | lc->filename = NULL; | |
252 | ||
defa0710 | 253 | ignore_result( loopcxt_set_device(lc, NULL) ); |
10ee5932 | 254 | loopcxt_deinit_iterator(lc); |
82756a74 KZ |
255 | |
256 | errno = errsv; | |
10ee5932 KZ |
257 | } |
258 | ||
259 | /* | |
260 | * @lc: context | |
261 | * | |
262 | * Returns newly allocated device path. | |
263 | */ | |
264 | char *loopcxt_strdup_device(struct loopdev_cxt *lc) | |
265 | { | |
cba69bb5 | 266 | if (!lc || !*lc->device) |
10ee5932 KZ |
267 | return NULL; |
268 | return strdup(lc->device); | |
269 | } | |
270 | ||
271 | /* | |
272 | * @lc: context | |
273 | * | |
274 | * Returns pointer device name in the @lc struct. | |
275 | */ | |
276 | const char *loopcxt_get_device(struct loopdev_cxt *lc) | |
277 | { | |
cba69bb5 | 278 | return lc && *lc->device ? lc->device : NULL; |
10ee5932 KZ |
279 | } |
280 | ||
281 | /* | |
282 | * @lc: context | |
283 | * | |
284 | * Returns pointer to the sysfs context (see lib/sysfs.c) | |
285 | */ | |
7604f85f | 286 | static struct path_cxt *loopcxt_get_sysfs(struct loopdev_cxt *lc) |
10ee5932 KZ |
287 | { |
288 | if (!lc || !*lc->device || (lc->flags & LOOPDEV_FL_NOSYSFS)) | |
289 | return NULL; | |
290 | ||
7604f85f | 291 | if (!lc->sysfs) { |
a6ca0456 | 292 | dev_t devno = loopcxt_get_devno(lc); |
aee31ddc | 293 | if (!devno) { |
0bf03740 | 294 | DBG(CXT, ul_debugobj(lc, "sysfs: failed devname to devno")); |
10ee5932 | 295 | return NULL; |
aee31ddc | 296 | } |
7604f85f KZ |
297 | |
298 | lc->sysfs = ul_new_sysfs_path(devno, NULL, NULL); | |
299 | if (!lc->sysfs) | |
0bf03740 | 300 | DBG(CXT, ul_debugobj(lc, "sysfs: init failed")); |
10ee5932 | 301 | } |
aee31ddc | 302 | |
7604f85f | 303 | return lc->sysfs; |
10ee5932 KZ |
304 | } |
305 | ||
ced1142d | 306 | static int __loopcxt_get_fd(struct loopdev_cxt *lc, mode_t mode) |
10ee5932 | 307 | { |
ced1142d KZ |
308 | int old = -1; |
309 | ||
10ee5932 | 310 | if (!lc || !*lc->device) |
fd7f0718 | 311 | return -EINVAL; |
10ee5932 | 312 | |
ced1142d KZ |
313 | /* It's okay to return a FD with read-write permissions if someone |
314 | * asked for read-only, but you shouldn't do the opposite. | |
315 | * | |
316 | * (O_RDONLY is a widely usable default.) | |
317 | */ | |
318 | if (lc->fd >= 0 && mode == O_RDWR && lc->mode == O_RDONLY) { | |
319 | DBG(CXT, ul_debugobj(lc, "closing already open device (mode mismatch)")); | |
320 | old = lc->fd; | |
321 | lc->fd = -1; | |
322 | } | |
323 | ||
fd7f0718 | 324 | if (lc->fd < 0) { |
ced1142d | 325 | lc->mode = mode; |
b1fa3e22 | 326 | lc->fd = open(lc->device, lc->mode | O_CLOEXEC); |
0bf03740 | 327 | DBG(CXT, ul_debugobj(lc, "open %s [%s]: %m", lc->device, |
ced1142d KZ |
328 | mode == O_RDONLY ? "ro" : |
329 | mode == O_RDWR ? "rw" : "??")); | |
330 | ||
331 | if (lc->fd < 0 && old >= 0) { | |
332 | /* restore original on error */ | |
333 | lc->fd = old; | |
334 | old = -1; | |
335 | } | |
fd7f0718 | 336 | } |
ced1142d KZ |
337 | |
338 | if (old >= 0) | |
339 | close(old); | |
10ee5932 KZ |
340 | return lc->fd; |
341 | } | |
342 | ||
ced1142d KZ |
343 | /* default is read-only file descriptor, it's enough for all ioctls */ |
344 | int loopcxt_get_fd(struct loopdev_cxt *lc) | |
345 | { | |
346 | return __loopcxt_get_fd(lc, O_RDONLY); | |
347 | } | |
348 | ||
349 | int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, mode_t mode) | |
fd7f0718 KZ |
350 | { |
351 | if (!lc) | |
352 | return -EINVAL; | |
353 | ||
354 | lc->fd = fd; | |
355 | lc->mode = mode; | |
356 | return 0; | |
357 | } | |
358 | ||
10ee5932 KZ |
359 | /* |
360 | * @lc: context | |
361 | * @flags: LOOPITER_FL_* flags | |
362 | * | |
29e204d1 | 363 | * Iterator can be used to scan list of the free or used loop devices. |
10ee5932 KZ |
364 | * |
365 | * Returns: <0 on error, 0 on success | |
366 | */ | |
367 | int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags) | |
368 | { | |
369 | struct loopdev_iter *iter; | |
370 | struct stat st; | |
371 | ||
372 | if (!lc) | |
373 | return -EINVAL; | |
374 | ||
aee31ddc | 375 | |
10ee5932 | 376 | iter = &lc->iter; |
0bf03740 | 377 | DBG(ITER, ul_debugobj(iter, "initialize")); |
10ee5932 KZ |
378 | |
379 | /* always zeroize | |
380 | */ | |
381 | memset(iter, 0, sizeof(*iter)); | |
382 | iter->ncur = -1; | |
383 | iter->flags = flags; | |
384 | iter->default_check = 1; | |
385 | ||
386 | if (!lc->extra_check) { | |
387 | /* | |
388 | * Check for /dev/loop/<N> subdirectory | |
389 | */ | |
82b4082e | 390 | if (!(lc->flags & LOOPDEV_FL_DEVSUBDIR) && |
10ee5932 KZ |
391 | stat(_PATH_DEV_LOOP, &st) == 0 && S_ISDIR(st.st_mode)) |
392 | lc->flags |= LOOPDEV_FL_DEVSUBDIR; | |
393 | ||
394 | lc->extra_check = 1; | |
395 | } | |
396 | return 0; | |
397 | } | |
398 | ||
399 | /* | |
400 | * @lc: context | |
401 | * | |
402 | * Returns: <0 on error, 0 on success | |
403 | */ | |
404 | int loopcxt_deinit_iterator(struct loopdev_cxt *lc) | |
405 | { | |
7552258a | 406 | struct loopdev_iter *iter; |
10ee5932 KZ |
407 | |
408 | if (!lc) | |
409 | return -EINVAL; | |
410 | ||
411 | iter = &lc->iter; | |
0bf03740 | 412 | DBG(ITER, ul_debugobj(iter, "de-initialize")); |
10ee5932 KZ |
413 | |
414 | free(iter->minors); | |
415 | if (iter->proc) | |
416 | fclose(iter->proc); | |
e4062c72 KZ |
417 | if (iter->sysblock) |
418 | closedir(iter->sysblock); | |
9a94b634 KZ |
419 | |
420 | memset(iter, 0, sizeof(*iter)); | |
10ee5932 KZ |
421 | return 0; |
422 | } | |
423 | ||
424 | /* | |
425 | * Same as loopcxt_set_device, but also checks if the device is | |
11026083 | 426 | * associated with any file. |
10ee5932 KZ |
427 | * |
428 | * Returns: <0 on error, 0 on success, 1 device does not match with | |
429 | * LOOPITER_FL_{USED,FREE} flags. | |
430 | */ | |
431 | static int loopiter_set_device(struct loopdev_cxt *lc, const char *device) | |
432 | { | |
433 | int rc = loopcxt_set_device(lc, device); | |
434 | int used; | |
435 | ||
436 | if (rc) | |
437 | return rc; | |
438 | ||
439 | if (!(lc->iter.flags & LOOPITER_FL_USED) && | |
440 | !(lc->iter.flags & LOOPITER_FL_FREE)) | |
441 | return 0; /* caller does not care about device status */ | |
442 | ||
443 | used = loopcxt_get_offset(lc, NULL) == 0; | |
444 | ||
445 | if ((lc->iter.flags & LOOPITER_FL_USED) && used) | |
446 | return 0; | |
447 | ||
448 | if ((lc->iter.flags & LOOPITER_FL_FREE) && !used) | |
449 | return 0; | |
450 | ||
0bf03740 KZ |
451 | DBG(ITER, ul_debugobj(&lc->iter, "failed to use %s device", lc->device)); |
452 | ||
defa0710 | 453 | ignore_result( loopcxt_set_device(lc, NULL) ); |
10ee5932 KZ |
454 | return 1; |
455 | } | |
456 | ||
457 | static int cmpnum(const void *p1, const void *p2) | |
458 | { | |
0145c00a KZ |
459 | return (((* (const int *) p1) > (* (const int *) p2)) - |
460 | ((* (const int *) p1) < (* (const int *) p2))); | |
10ee5932 KZ |
461 | } |
462 | ||
463 | /* | |
464 | * The classic scandir() is more expensive and less portable. | |
465 | * We needn't full loop device names -- loop numbers (loop<N>) | |
466 | * are enough. | |
467 | */ | |
468 | static int loop_scandir(const char *dirname, int **ary, int hasprefix) | |
469 | { | |
470 | DIR *dir; | |
471 | struct dirent *d; | |
472 | unsigned int n, count = 0, arylen = 0; | |
473 | ||
474 | if (!dirname || !ary) | |
475 | return 0; | |
0bf03740 KZ |
476 | |
477 | DBG(ITER, ul_debug("scan dir: %s", dirname)); | |
478 | ||
10ee5932 KZ |
479 | dir = opendir(dirname); |
480 | if (!dir) | |
481 | return 0; | |
10ee5932 KZ |
482 | free(*ary); |
483 | *ary = NULL; | |
484 | ||
485 | while((d = readdir(dir))) { | |
486 | #ifdef _DIRENT_HAVE_D_TYPE | |
487 | if (d->d_type != DT_BLK && d->d_type != DT_UNKNOWN && | |
488 | d->d_type != DT_LNK) | |
489 | continue; | |
490 | #endif | |
491 | if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, "..")) | |
492 | continue; | |
493 | ||
494 | if (hasprefix) { | |
495 | /* /dev/loop<N> */ | |
496 | if (sscanf(d->d_name, "loop%u", &n) != 1) | |
497 | continue; | |
498 | } else { | |
499 | /* /dev/loop/<N> */ | |
500 | char *end = NULL; | |
501 | ||
f0fe8ab5 | 502 | errno = 0; |
10ee5932 KZ |
503 | n = strtol(d->d_name, &end, 10); |
504 | if (d->d_name == end || (end && *end) || errno) | |
505 | continue; | |
506 | } | |
507 | if (n < LOOPDEV_DEFAULT_NNODES) | |
508 | continue; /* ignore loop<0..7> */ | |
509 | ||
510 | if (count + 1 > arylen) { | |
511 | int *tmp; | |
512 | ||
513 | arylen += 1; | |
514 | ||
64d6d400 | 515 | tmp = reallocarray(*ary, arylen, sizeof(int)); |
10ee5932 KZ |
516 | if (!tmp) { |
517 | free(*ary); | |
34f6177a | 518 | *ary = NULL; |
2e566efd | 519 | closedir(dir); |
10ee5932 KZ |
520 | return -1; |
521 | } | |
522 | *ary = tmp; | |
523 | } | |
fc8b1f36 KZ |
524 | if (*ary) |
525 | (*ary)[count++] = n; | |
10ee5932 | 526 | } |
fc8b1f36 | 527 | if (count && *ary) |
10ee5932 KZ |
528 | qsort(*ary, count, sizeof(int), cmpnum); |
529 | ||
530 | closedir(dir); | |
531 | return count; | |
532 | } | |
533 | ||
e4062c72 KZ |
534 | /* |
535 | * Set the next *used* loop device according to /proc/partitions. | |
536 | * | |
537 | * Loop devices smaller than 512 bytes are invisible for this function. | |
538 | */ | |
539 | static int loopcxt_next_from_proc(struct loopdev_cxt *lc) | |
540 | { | |
541 | struct loopdev_iter *iter = &lc->iter; | |
542 | char buf[BUFSIZ]; | |
543 | ||
0bf03740 | 544 | DBG(ITER, ul_debugobj(iter, "scan /proc/partitions")); |
e4062c72 KZ |
545 | |
546 | if (!iter->proc) | |
b1fa3e22 | 547 | iter->proc = fopen(_PATH_PROC_PARTITIONS, "r" UL_CLOEXECSTR); |
e4062c72 KZ |
548 | if (!iter->proc) |
549 | return 1; | |
550 | ||
551 | while (fgets(buf, sizeof(buf), iter->proc)) { | |
552 | unsigned int m; | |
657d9adb | 553 | char name[128 + 1]; |
e4062c72 KZ |
554 | |
555 | ||
556 | if (sscanf(buf, " %u %*s %*s %128[^\n ]", | |
557 | &m, name) != 2 || m != LOOPDEV_MAJOR) | |
558 | continue; | |
559 | ||
0bf03740 | 560 | DBG(ITER, ul_debugobj(iter, "checking %s", name)); |
e4062c72 KZ |
561 | |
562 | if (loopiter_set_device(lc, name) == 0) | |
563 | return 0; | |
564 | } | |
565 | ||
566 | return 1; | |
567 | } | |
568 | ||
569 | /* | |
570 | * Set the next *used* loop device according to | |
571 | * /sys/block/loopN/loop/backing_file (kernel >= 2.6.37 is required). | |
572 | * | |
573 | * This is preferred method. | |
574 | */ | |
575 | static int loopcxt_next_from_sysfs(struct loopdev_cxt *lc) | |
576 | { | |
577 | struct loopdev_iter *iter = &lc->iter; | |
578 | struct dirent *d; | |
579 | int fd; | |
580 | ||
0bf03740 | 581 | DBG(ITER, ul_debugobj(iter, "scanning /sys/block")); |
e4062c72 KZ |
582 | |
583 | if (!iter->sysblock) | |
584 | iter->sysblock = opendir(_PATH_SYS_BLOCK); | |
585 | ||
586 | if (!iter->sysblock) | |
587 | return 1; | |
588 | ||
589 | fd = dirfd(iter->sysblock); | |
590 | ||
591 | while ((d = readdir(iter->sysblock))) { | |
acecab61 | 592 | char name[NAME_MAX + 18 + 1]; |
e4062c72 KZ |
593 | struct stat st; |
594 | ||
0bf03740 | 595 | DBG(ITER, ul_debugobj(iter, "check %s", d->d_name)); |
e4062c72 KZ |
596 | |
597 | if (strcmp(d->d_name, ".") == 0 | |
598 | || strcmp(d->d_name, "..") == 0 | |
599 | || strncmp(d->d_name, "loop", 4) != 0) | |
600 | continue; | |
601 | ||
602 | snprintf(name, sizeof(name), "%s/loop/backing_file", d->d_name); | |
2208b3cc | 603 | if (fstatat(fd, name, &st, 0) != 0) |
e4062c72 KZ |
604 | continue; |
605 | ||
606 | if (loopiter_set_device(lc, d->d_name) == 0) | |
607 | return 0; | |
608 | } | |
609 | ||
610 | return 1; | |
611 | } | |
612 | ||
10ee5932 KZ |
613 | /* |
614 | * @lc: context, has to initialized by loopcxt_init_iterator() | |
615 | * | |
af5efcd8 | 616 | * Returns: 0 on success, < 0 on error, 1 at the end of scanning. The details |
10ee5932 KZ |
617 | * about the current loop device are available by |
618 | * loopcxt_get_{fd,backing_file,device,offset, ...} functions. | |
619 | */ | |
620 | int loopcxt_next(struct loopdev_cxt *lc) | |
621 | { | |
622 | struct loopdev_iter *iter; | |
623 | ||
624 | if (!lc) | |
625 | return -EINVAL; | |
aee31ddc | 626 | |
aee31ddc | 627 | |
10ee5932 KZ |
628 | iter = &lc->iter; |
629 | if (iter->done) | |
630 | return 1; | |
631 | ||
0bf03740 KZ |
632 | DBG(ITER, ul_debugobj(iter, "next")); |
633 | ||
10ee5932 KZ |
634 | /* A) Look for used loop devices in /proc/partitions ("losetup -a" only) |
635 | */ | |
636 | if (iter->flags & LOOPITER_FL_USED) { | |
e4062c72 KZ |
637 | int rc; |
638 | ||
639 | if (loopcxt_sysfs_available(lc)) | |
640 | rc = loopcxt_next_from_sysfs(lc); | |
641 | else | |
642 | rc = loopcxt_next_from_proc(lc); | |
643 | if (rc == 0) | |
644 | return 0; | |
10ee5932 KZ |
645 | goto done; |
646 | } | |
647 | ||
648 | /* B) Classic way, try first eight loop devices (default number | |
649 | * of loop devices). This is enough for 99% of all cases. | |
650 | */ | |
651 | if (iter->default_check) { | |
0bf03740 | 652 | DBG(ITER, ul_debugobj(iter, "next: default check")); |
10ee5932 KZ |
653 | for (++iter->ncur; iter->ncur < LOOPDEV_DEFAULT_NNODES; |
654 | iter->ncur++) { | |
655 | char name[16]; | |
656 | snprintf(name, sizeof(name), "loop%d", iter->ncur); | |
657 | ||
658 | if (loopiter_set_device(lc, name) == 0) | |
659 | return 0; | |
660 | } | |
661 | iter->default_check = 0; | |
662 | } | |
663 | ||
664 | /* C) the worst possibility, scan whole /dev or /dev/loop/<N> | |
665 | */ | |
666 | if (!iter->minors) { | |
0bf03740 | 667 | DBG(ITER, ul_debugobj(iter, "next: scanning /dev")); |
10ee5932 KZ |
668 | iter->nminors = (lc->flags & LOOPDEV_FL_DEVSUBDIR) ? |
669 | loop_scandir(_PATH_DEV_LOOP, &iter->minors, 0) : | |
670 | loop_scandir(_PATH_DEV, &iter->minors, 1); | |
671 | iter->ncur = -1; | |
672 | } | |
673 | for (++iter->ncur; iter->ncur < iter->nminors; iter->ncur++) { | |
674 | char name[16]; | |
675 | snprintf(name, sizeof(name), "loop%d", iter->minors[iter->ncur]); | |
676 | ||
677 | if (loopiter_set_device(lc, name) == 0) | |
678 | return 0; | |
679 | } | |
680 | done: | |
681 | loopcxt_deinit_iterator(lc); | |
682 | return 1; | |
683 | } | |
684 | ||
685 | /* | |
686 | * @device: path to device | |
687 | */ | |
688 | int is_loopdev(const char *device) | |
689 | { | |
690 | struct stat st; | |
fbc2fe82 KZ |
691 | int rc = 0; |
692 | ||
693 | if (!device || stat(device, &st) != 0 || !S_ISBLK(st.st_mode)) | |
694 | rc = 0; | |
695 | else if (major(st.st_rdev) == LOOPDEV_MAJOR) | |
696 | rc = 1; | |
d4423cce | 697 | else if (sysfs_devno_is_wholedisk(st.st_rdev)) { |
fbc2fe82 KZ |
698 | /* It's possible that kernel creates a device with a different |
699 | * major number ... check by /sys it's really loop device. | |
700 | */ | |
701 | char name[PATH_MAX], *cn, *p = NULL; | |
702 | ||
703 | snprintf(name, sizeof(name), _PATH_SYS_DEVBLOCK "/%d:%d", | |
704 | major(st.st_rdev), minor(st.st_rdev)); | |
705 | cn = canonicalize_path(name); | |
706 | if (cn) | |
707 | p = stripoff_last_component(cn); | |
708 | rc = p && startswith(p, "loop"); | |
709 | free(cn); | |
710 | } | |
10ee5932 | 711 | |
fbc2fe82 KZ |
712 | if (rc == 0) |
713 | errno = ENODEV; | |
714 | return rc; | |
10ee5932 KZ |
715 | } |
716 | ||
717 | /* | |
718 | * @lc: context | |
719 | * | |
720 | * Returns result from LOOP_GET_STAT64 ioctl or NULL on error. | |
721 | */ | |
722 | struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc) | |
723 | { | |
724 | int fd; | |
725 | ||
85794fb0 KZ |
726 | if (!lc || lc->info_failed) { |
727 | errno = EINVAL; | |
10ee5932 | 728 | return NULL; |
85794fb0 KZ |
729 | } |
730 | errno = 0; | |
10ee5932 | 731 | if (lc->has_info) |
d5fd456c | 732 | return &lc->config.info; |
10ee5932 KZ |
733 | |
734 | fd = loopcxt_get_fd(lc); | |
735 | if (fd < 0) | |
736 | return NULL; | |
737 | ||
d5fd456c | 738 | if (ioctl(fd, LOOP_GET_STATUS64, &lc->config.info) == 0) { |
10ee5932 | 739 | lc->has_info = 1; |
6c224de1 | 740 | lc->info_failed = 0; |
0bf03740 | 741 | DBG(CXT, ul_debugobj(lc, "reading loop_info64 OK")); |
d5fd456c | 742 | return &lc->config.info; |
10ee5932 KZ |
743 | } |
744 | ||
85794fb0 | 745 | lc->info_failed = 1; |
0bf03740 | 746 | DBG(CXT, ul_debugobj(lc, "reading loop_info64 FAILED")); |
85794fb0 | 747 | |
10ee5932 KZ |
748 | return NULL; |
749 | } | |
750 | ||
751 | /* | |
752 | * @lc: context | |
753 | * | |
311e33af | 754 | * Returns (allocated) string with path to the file associated |
10ee5932 KZ |
755 | * with the current loop device. |
756 | */ | |
757 | char *loopcxt_get_backing_file(struct loopdev_cxt *lc) | |
758 | { | |
7604f85f | 759 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
10ee5932 KZ |
760 | char *res = NULL; |
761 | ||
762 | if (sysfs) | |
fd7f0718 | 763 | /* |
11026083 | 764 | * This is always preferred, the loop_info64 |
fd7f0718 KZ |
765 | * has too small buffer for the filename. |
766 | */ | |
7604f85f | 767 | ul_path_read_string(sysfs, &res, "loop/backing_file"); |
10ee5932 KZ |
768 | |
769 | if (!res && loopcxt_ioctl_enabled(lc)) { | |
770 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
771 | ||
772 | if (lo) { | |
773 | lo->lo_file_name[LO_NAME_SIZE - 2] = '*'; | |
774 | lo->lo_file_name[LO_NAME_SIZE - 1] = '\0'; | |
775 | res = strdup((char *) lo->lo_file_name); | |
776 | } | |
777 | } | |
aee31ddc | 778 | |
0bf03740 | 779 | DBG(CXT, ul_debugobj(lc, "get_backing_file [%s]", res)); |
10ee5932 KZ |
780 | return res; |
781 | } | |
782 | ||
db8f7815 KZ |
783 | /* |
784 | * @lc: context | |
785 | * | |
786 | * Returns (allocated) string with loop reference. The same as backing file by | |
787 | * default. | |
788 | */ | |
789 | char *loopcxt_get_refname(struct loopdev_cxt *lc) | |
790 | { | |
791 | char *res = NULL; | |
792 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
793 | ||
794 | if (lo) { | |
795 | lo->lo_file_name[LO_NAME_SIZE - 1] = '\0'; | |
796 | res = strdup((char *) lo->lo_file_name); | |
797 | } | |
798 | ||
799 | DBG(CXT, ul_debugobj(lc, "get_refname [%s]", res)); | |
800 | return res; | |
801 | } | |
802 | ||
10ee5932 KZ |
803 | /* |
804 | * @lc: context | |
805 | * @offset: returns offset number for the given device | |
806 | * | |
807 | * Returns: <0 on error, 0 on success | |
808 | */ | |
809 | int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset) | |
810 | { | |
7604f85f | 811 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
10ee5932 KZ |
812 | int rc = -EINVAL; |
813 | ||
814 | if (sysfs) | |
fb4b6b11 JK |
815 | if (ul_path_read_u64(sysfs, offset, "loop/offset") == 0) |
816 | rc = 0; | |
10ee5932 KZ |
817 | |
818 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
819 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
820 | if (lo) { | |
821 | if (offset) | |
822 | *offset = lo->lo_offset; | |
6c224de1 | 823 | rc = 0; |
85794fb0 KZ |
824 | } else |
825 | rc = -errno; | |
10ee5932 KZ |
826 | } |
827 | ||
0bf03740 | 828 | DBG(CXT, ul_debugobj(lc, "get_offset [rc=%d]", rc)); |
10ee5932 KZ |
829 | return rc; |
830 | } | |
831 | ||
a1a41597 SB |
832 | /* |
833 | * @lc: context | |
834 | * @blocksize: returns logical blocksize for the given device | |
835 | * | |
836 | * Returns: <0 on error, 0 on success | |
837 | */ | |
838 | int loopcxt_get_blocksize(struct loopdev_cxt *lc, uint64_t *blocksize) | |
839 | { | |
7604f85f | 840 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
a1a41597 SB |
841 | int rc = -EINVAL; |
842 | ||
843 | if (sysfs) | |
fb4b6b11 JK |
844 | if (ul_path_read_u64(sysfs, blocksize, "queue/logical_block_size") == 0) |
845 | rc = 0; | |
a1a41597 SB |
846 | |
847 | /* Fallback based on BLKSSZGET ioctl */ | |
848 | if (rc) { | |
849 | int fd = loopcxt_get_fd(lc); | |
850 | int sz = 0; | |
851 | ||
852 | if (fd < 0) | |
853 | return -EINVAL; | |
854 | rc = blkdev_get_sector_size(fd, &sz); | |
855 | if (rc) | |
856 | return rc; | |
857 | ||
858 | *blocksize = sz; | |
859 | } | |
860 | ||
861 | DBG(CXT, ul_debugobj(lc, "get_blocksize [rc=%d]", rc)); | |
862 | return rc; | |
863 | } | |
864 | ||
10ee5932 KZ |
865 | /* |
866 | * @lc: context | |
867 | * @sizelimit: returns size limit for the given device | |
868 | * | |
869 | * Returns: <0 on error, 0 on success | |
870 | */ | |
871 | int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size) | |
872 | { | |
7604f85f | 873 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
10ee5932 KZ |
874 | int rc = -EINVAL; |
875 | ||
876 | if (sysfs) | |
fb4b6b11 JK |
877 | if (ul_path_read_u64(sysfs, size, "loop/sizelimit") == 0) |
878 | rc = 0; | |
10ee5932 KZ |
879 | |
880 | if (rc && loopcxt_ioctl_enabled(lc)) { | |
881 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
882 | if (lo) { | |
883 | if (size) | |
884 | *size = lo->lo_sizelimit; | |
6c224de1 | 885 | rc = 0; |
85794fb0 KZ |
886 | } else |
887 | rc = -errno; | |
10ee5932 KZ |
888 | } |
889 | ||
0bf03740 | 890 | DBG(CXT, ul_debugobj(lc, "get_sizelimit [rc=%d]", rc)); |
6c224de1 KZ |
891 | return rc; |
892 | } | |
893 | ||
894 | /* | |
895 | * @lc: context | |
a6ca0456 | 896 | * @type: returns encryption type |
6c224de1 KZ |
897 | * |
898 | * Cryptoloop is DEPRECATED! | |
899 | * | |
900 | * Returns: <0 on error, 0 on success | |
901 | */ | |
902 | int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type) | |
903 | { | |
904 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 905 | int rc; |
6c224de1 | 906 | |
85794fb0 | 907 | /* not provided by sysfs */ |
6c224de1 KZ |
908 | if (lo) { |
909 | if (type) | |
910 | *type = lo->lo_encrypt_type; | |
911 | rc = 0; | |
85794fb0 KZ |
912 | } else |
913 | rc = -errno; | |
914 | ||
0bf03740 | 915 | DBG(CXT, ul_debugobj(lc, "get_encrypt_type [rc=%d]", rc)); |
6c224de1 KZ |
916 | return rc; |
917 | } | |
918 | ||
919 | /* | |
920 | * @lc: context | |
6c224de1 KZ |
921 | * |
922 | * Cryptoloop is DEPRECATED! | |
923 | * | |
924 | * Returns: <0 on error, 0 on success | |
925 | */ | |
926 | const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc) | |
927 | { | |
928 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
929 | ||
930 | if (lo) | |
931 | return (char *) lo->lo_crypt_name; | |
932 | ||
0bf03740 | 933 | DBG(CXT, ul_debugobj(lc, "get_crypt_name failed")); |
6c224de1 KZ |
934 | return NULL; |
935 | } | |
936 | ||
937 | /* | |
938 | * @lc: context | |
939 | * @devno: returns backing file devno | |
940 | * | |
941 | * Returns: <0 on error, 0 on success | |
942 | */ | |
943 | int loopcxt_get_backing_devno(struct loopdev_cxt *lc, dev_t *devno) | |
944 | { | |
945 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 946 | int rc; |
6c224de1 KZ |
947 | |
948 | if (lo) { | |
949 | if (devno) | |
950 | *devno = lo->lo_device; | |
951 | rc = 0; | |
85794fb0 KZ |
952 | } else |
953 | rc = -errno; | |
954 | ||
0bf03740 | 955 | DBG(CXT, ul_debugobj(lc, "get_backing_devno [rc=%d]", rc)); |
6c224de1 KZ |
956 | return rc; |
957 | } | |
958 | ||
959 | /* | |
960 | * @lc: context | |
961 | * @ino: returns backing file inode | |
962 | * | |
963 | * Returns: <0 on error, 0 on success | |
964 | */ | |
965 | int loopcxt_get_backing_inode(struct loopdev_cxt *lc, ino_t *ino) | |
966 | { | |
967 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
85794fb0 | 968 | int rc; |
6c224de1 KZ |
969 | |
970 | if (lo) { | |
971 | if (ino) | |
972 | *ino = lo->lo_inode; | |
973 | rc = 0; | |
85794fb0 KZ |
974 | } else |
975 | rc = -errno; | |
976 | ||
0bf03740 | 977 | DBG(CXT, ul_debugobj(lc, "get_backing_inode [rc=%d]", rc)); |
10ee5932 KZ |
978 | return rc; |
979 | } | |
980 | ||
59d749c3 KZ |
981 | /* |
982 | * Check if the kernel supports partitioned loop devices. | |
983 | * | |
984 | * Notes: | |
985 | * - kernels < 3.2 support partitioned loop devices and PT scanning | |
9e930041 | 986 | * only if max_part= module parameter is non-zero |
59d749c3 KZ |
987 | * |
988 | * - kernels >= 3.2 always support partitioned loop devices | |
989 | * | |
990 | * - kernels >= 3.2 always support BLKPG_{ADD,DEL}_PARTITION ioctls | |
991 | * | |
992 | * - kernels >= 3.2 enable PT scanner only if max_part= is non-zero or if the | |
993 | * LO_FLAGS_PARTSCAN flag is set for the device. The PT scanner is disabled | |
994 | * by default. | |
995 | * | |
996 | * See kernel commit e03c8dd14915fabc101aa495828d58598dc5af98. | |
997 | */ | |
998 | int loopmod_supports_partscan(void) | |
999 | { | |
1000 | int rc, ret = 0; | |
1001 | FILE *f; | |
1002 | ||
1003 | if (get_linux_version() >= KERNEL_VERSION(3,2,0)) | |
1004 | return 1; | |
1005 | ||
b1fa3e22 | 1006 | f = fopen("/sys/module/loop/parameters/max_part", "r" UL_CLOEXECSTR); |
59d749c3 KZ |
1007 | if (!f) |
1008 | return 0; | |
1009 | rc = fscanf(f, "%d", &ret); | |
1010 | fclose(f); | |
8b04761d | 1011 | return rc == 1 ? ret : 0; |
59d749c3 KZ |
1012 | } |
1013 | ||
10ee5932 KZ |
1014 | /* |
1015 | * @lc: context | |
1016 | * | |
59d749c3 | 1017 | * Returns: 1 if the partscan flags is set *or* (for old kernels) partitions |
9e930041 | 1018 | * scanning is enabled for all loop devices. |
59d749c3 KZ |
1019 | */ |
1020 | int loopcxt_is_partscan(struct loopdev_cxt *lc) | |
1021 | { | |
7604f85f | 1022 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
59d749c3 KZ |
1023 | |
1024 | if (sysfs) { | |
1025 | /* kernel >= 3.2 */ | |
1026 | int fl; | |
7604f85f | 1027 | if (ul_path_read_s32(sysfs, &fl, "loop/partscan") == 0) |
59d749c3 KZ |
1028 | return fl; |
1029 | } | |
1030 | ||
1031 | /* old kernels (including kernels without loopN/loop/<flags> directory */ | |
1032 | return loopmod_supports_partscan(); | |
1033 | } | |
1034 | ||
1035 | /* | |
1036 | * @lc: context | |
1037 | * | |
1038 | * Returns: 1 if the autoclear flags is set. | |
10ee5932 KZ |
1039 | */ |
1040 | int loopcxt_is_autoclear(struct loopdev_cxt *lc) | |
1041 | { | |
7604f85f | 1042 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
10ee5932 KZ |
1043 | |
1044 | if (sysfs) { | |
1045 | int fl; | |
7604f85f | 1046 | if (ul_path_read_s32(sysfs, &fl, "loop/autoclear") == 0) |
10ee5932 KZ |
1047 | return fl; |
1048 | } | |
1049 | ||
1050 | if (loopcxt_ioctl_enabled(lc)) { | |
1051 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
1052 | if (lo) | |
1053 | return lo->lo_flags & LO_FLAGS_AUTOCLEAR; | |
1054 | } | |
1055 | return 0; | |
1056 | } | |
1057 | ||
fd7f0718 KZ |
1058 | /* |
1059 | * @lc: context | |
1060 | * | |
59d749c3 | 1061 | * Returns: 1 if the readonly flags is set. |
fd7f0718 KZ |
1062 | */ |
1063 | int loopcxt_is_readonly(struct loopdev_cxt *lc) | |
1064 | { | |
7604f85f | 1065 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
fd7f0718 KZ |
1066 | |
1067 | if (sysfs) { | |
1068 | int fl; | |
7604f85f | 1069 | if (ul_path_read_s32(sysfs, &fl, "ro") == 0) |
fd7f0718 KZ |
1070 | return fl; |
1071 | } | |
1072 | ||
1073 | if (loopcxt_ioctl_enabled(lc)) { | |
1074 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
1075 | if (lo) | |
1076 | return lo->lo_flags & LO_FLAGS_READ_ONLY; | |
1077 | } | |
1078 | return 0; | |
1079 | } | |
1080 | ||
faeef4d2 ML |
1081 | /* |
1082 | * @lc: context | |
1083 | * | |
1084 | * Returns: 1 if the dio flags is set. | |
1085 | */ | |
1086 | int loopcxt_is_dio(struct loopdev_cxt *lc) | |
1087 | { | |
7604f85f | 1088 | struct path_cxt *sysfs = loopcxt_get_sysfs(lc); |
faeef4d2 ML |
1089 | |
1090 | if (sysfs) { | |
1091 | int fl; | |
7604f85f | 1092 | if (ul_path_read_s32(sysfs, &fl, "loop/dio") == 0) |
faeef4d2 ML |
1093 | return fl; |
1094 | } | |
1095 | if (loopcxt_ioctl_enabled(lc)) { | |
1096 | struct loop_info64 *lo = loopcxt_get_info(lc); | |
1097 | if (lo) | |
1098 | return lo->lo_flags & LO_FLAGS_DIRECT_IO; | |
1099 | } | |
1100 | return 0; | |
1101 | } | |
1102 | ||
6c224de1 KZ |
1103 | /* |
1104 | * @lc: context | |
1105 | * @st: backing file stat or NULL | |
1106 | * @backing_file: filename | |
c444a71b KZ |
1107 | * @offset: offset (use LOOPDEV_FL_OFFSET if specified) |
1108 | * @sizelimit: size limit (use LOOPDEV_FL_SIZELIMIT if specified) | |
1109 | * @flags: LOOPDEV_FL_{OFFSET,SIZELIMIT} | |
6c224de1 KZ |
1110 | * |
1111 | * Returns 1 if the current @lc loopdev is associated with the given backing | |
1112 | * file. Note that the preferred way is to use devno and inode number rather | |
1113 | * than filename. The @backing_file filename is poor solution usable in case | |
1114 | * that you don't have rights to call stat(). | |
1115 | * | |
74a4705a SB |
1116 | * LOOPDEV_FL_SIZELIMIT requires LOOPDEV_FL_OFFSET being set as well. |
1117 | * | |
6c224de1 KZ |
1118 | * Don't forget that old kernels provide very restricted (in size) backing |
1119 | * filename by LOOP_GET_STAT64 ioctl only. | |
1120 | */ | |
1121 | int loopcxt_is_used(struct loopdev_cxt *lc, | |
1122 | struct stat *st, | |
1123 | const char *backing_file, | |
1124 | uint64_t offset, | |
74a4705a | 1125 | uint64_t sizelimit, |
6c224de1 KZ |
1126 | int flags) |
1127 | { | |
3011b381 KZ |
1128 | ino_t ino = 0; |
1129 | dev_t dev = 0; | |
6c224de1 KZ |
1130 | |
1131 | if (!lc) | |
1132 | return 0; | |
1133 | ||
0bf03740 | 1134 | DBG(CXT, ul_debugobj(lc, "checking %s vs. %s", |
6c224de1 KZ |
1135 | loopcxt_get_device(lc), |
1136 | backing_file)); | |
1137 | ||
1138 | if (st && loopcxt_get_backing_inode(lc, &ino) == 0 && | |
1139 | loopcxt_get_backing_devno(lc, &dev) == 0) { | |
1140 | ||
1141 | if (ino == st->st_ino && dev == st->st_dev) | |
1142 | goto found; | |
1143 | ||
1144 | /* don't use filename if we have devno and inode */ | |
1145 | return 0; | |
1146 | } | |
1147 | ||
1148 | /* poor man's solution */ | |
1149 | if (backing_file) { | |
1150 | char *name = loopcxt_get_backing_file(lc); | |
1151 | int rc = name && strcmp(name, backing_file) == 0; | |
1152 | ||
1153 | free(name); | |
1154 | if (rc) | |
1155 | goto found; | |
1156 | } | |
1157 | ||
1158 | return 0; | |
1159 | found: | |
1160 | if (flags & LOOPDEV_FL_OFFSET) { | |
3011b381 | 1161 | uint64_t off = 0; |
6c224de1 | 1162 | |
74a4705a SB |
1163 | int rc = loopcxt_get_offset(lc, &off) == 0 && off == offset; |
1164 | ||
1165 | if (rc && flags & LOOPDEV_FL_SIZELIMIT) { | |
3011b381 | 1166 | uint64_t sz = 0; |
74a4705a SB |
1167 | |
1168 | return loopcxt_get_sizelimit(lc, &sz) == 0 && sz == sizelimit; | |
042f62df RP |
1169 | } |
1170 | return rc; | |
6c224de1 KZ |
1171 | } |
1172 | return 1; | |
1173 | } | |
1174 | ||
fd7f0718 KZ |
1175 | /* |
1176 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1177 | */ | |
10ee5932 KZ |
1178 | int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset) |
1179 | { | |
1180 | if (!lc) | |
1181 | return -EINVAL; | |
d5fd456c | 1182 | lc->config.info.lo_offset = offset; |
aee31ddc | 1183 | |
0bf03740 | 1184 | DBG(CXT, ul_debugobj(lc, "set offset=%jd", offset)); |
10ee5932 KZ |
1185 | return 0; |
1186 | } | |
1187 | ||
fd7f0718 KZ |
1188 | /* |
1189 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1190 | */ | |
10ee5932 KZ |
1191 | int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit) |
1192 | { | |
1193 | if (!lc) | |
1194 | return -EINVAL; | |
d5fd456c | 1195 | lc->config.info.lo_sizelimit = sizelimit; |
aee31ddc | 1196 | |
0bf03740 | 1197 | DBG(CXT, ul_debugobj(lc, "set sizelimit=%jd", sizelimit)); |
10ee5932 KZ |
1198 | return 0; |
1199 | } | |
1200 | ||
75d239ff KZ |
1201 | /* |
1202 | * The blocksize will be used by loopcxt_set_device(). For already exiting | |
1203 | * devices use loopcxt_ioctl_blocksize(). | |
1204 | * | |
1205 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1206 | */ | |
1207 | int loopcxt_set_blocksize(struct loopdev_cxt *lc, uint64_t blocksize) | |
1208 | { | |
1209 | if (!lc) | |
1210 | return -EINVAL; | |
1211 | lc->blocksize = blocksize; | |
1212 | ||
1213 | DBG(CXT, ul_debugobj(lc, "set blocksize=%jd", blocksize)); | |
1214 | return 0; | |
1215 | } | |
1216 | ||
10ee5932 KZ |
1217 | /* |
1218 | * @lc: context | |
1219 | * @flags: kernel LO_FLAGS_{READ_ONLY,USE_AOPS,AUTOCLEAR} flags | |
1220 | * | |
fd7f0718 KZ |
1221 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
1222 | * | |
10ee5932 KZ |
1223 | * Returns: 0 on success, <0 on error. |
1224 | */ | |
1225 | int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags) | |
1226 | { | |
1227 | if (!lc) | |
1228 | return -EINVAL; | |
d5fd456c | 1229 | lc->config.info.lo_flags = flags; |
aee31ddc | 1230 | |
0bf03740 | 1231 | DBG(CXT, ul_debugobj(lc, "set flags=%u", (unsigned) flags)); |
10ee5932 KZ |
1232 | return 0; |
1233 | } | |
1234 | ||
db8f7815 KZ |
1235 | /* |
1236 | * @lc: context | |
1237 | * @refname: reference name (used to overwrite lo_file_name where is backing | |
1238 | * file by default) | |
1239 | * | |
1240 | * The setting is removed by loopcxt_set_device() loopcxt_next()! | |
1241 | * | |
1242 | * Returns: 0 on success, <0 on error. | |
1243 | */ | |
1244 | int loopcxt_set_refname(struct loopdev_cxt *lc, const char *refname) | |
1245 | { | |
1246 | if (!lc) | |
1247 | return -EINVAL; | |
1248 | ||
1249 | memset(lc->config.info.lo_file_name, 0, sizeof(lc->config.info.lo_file_name)); | |
1250 | if (refname) | |
1251 | xstrncpy((char *)lc->config.info.lo_file_name, refname, LO_NAME_SIZE); | |
1252 | ||
1253 | DBG(CXT, ul_debugobj(lc, "set refname=%s", (char *)lc->config.info.lo_file_name)); | |
1254 | return 0; | |
1255 | } | |
1256 | ||
10ee5932 KZ |
1257 | /* |
1258 | * @lc: context | |
1259 | * @filename: backing file path (the path will be canonicalized) | |
1260 | * | |
fd7f0718 KZ |
1261 | * The setting is removed by loopcxt_set_device() loopcxt_next()! |
1262 | * | |
10ee5932 KZ |
1263 | * Returns: 0 on success, <0 on error. |
1264 | */ | |
1265 | int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename) | |
1266 | { | |
1267 | if (!lc) | |
1268 | return -EINVAL; | |
1269 | ||
1270 | lc->filename = canonicalize_path(filename); | |
1271 | if (!lc->filename) | |
1272 | return -errno; | |
1273 | ||
db8f7815 KZ |
1274 | if (!lc->config.info.lo_file_name[0]) |
1275 | loopcxt_set_refname(lc, lc->filename); | |
10ee5932 | 1276 | |
db8f7815 | 1277 | DBG(CXT, ul_debugobj(lc, "set backing file=%s", lc->filename)); |
10ee5932 KZ |
1278 | return 0; |
1279 | } | |
1280 | ||
293714c0 JM |
1281 | /* |
1282 | * In kernels prior to v3.9, if the offset or sizelimit options | |
1283 | * are used, the block device's size won't be synced automatically. | |
1284 | * blockdev --getsize64 and filesystems will use the backing | |
1285 | * file size until the block device has been re-opened or the | |
1286 | * LOOP_SET_CAPACITY ioctl is called to sync the sizes. | |
1287 | * | |
1288 | * Since mount -oloop uses the LO_FLAGS_AUTOCLEAR option and passes | |
1289 | * the open file descriptor to the mount system call, we need to use | |
1290 | * the ioctl. Calling losetup directly doesn't have this problem since | |
1291 | * it closes the device when it exits and whatever consumes the device | |
1292 | * next will re-open it, causing the resync. | |
1293 | */ | |
1294 | static int loopcxt_check_size(struct loopdev_cxt *lc, int file_fd) | |
1295 | { | |
1296 | uint64_t size, expected_size; | |
1297 | int dev_fd; | |
1298 | struct stat st; | |
1299 | ||
d5fd456c | 1300 | if (!lc->config.info.lo_offset && !lc->config.info.lo_sizelimit) |
293714c0 JM |
1301 | return 0; |
1302 | ||
01307ecf | 1303 | if (fstat(file_fd, &st)) { |
0bf03740 | 1304 | DBG(CXT, ul_debugobj(lc, "failed to fstat backing file")); |
293714c0 | 1305 | return -errno; |
01307ecf | 1306 | } |
e3b6cb87 KZ |
1307 | if (S_ISBLK(st.st_mode)) { |
1308 | if (blkdev_get_size(file_fd, | |
01307ecf | 1309 | (unsigned long long *) &expected_size)) { |
0bf03740 | 1310 | DBG(CXT, ul_debugobj(lc, "failed to determine device size")); |
e3b6cb87 | 1311 | return -errno; |
01307ecf | 1312 | } |
e3b6cb87 KZ |
1313 | } else |
1314 | expected_size = st.st_size; | |
1315 | ||
d5fd456c | 1316 | if (expected_size == 0 || expected_size <= lc->config.info.lo_offset) { |
0bf03740 | 1317 | DBG(CXT, ul_debugobj(lc, "failed to determine expected size")); |
e3b6cb87 KZ |
1318 | return 0; /* ignore this error */ |
1319 | } | |
293714c0 | 1320 | |
d5fd456c SK |
1321 | if (lc->config.info.lo_offset > 0) |
1322 | expected_size -= lc->config.info.lo_offset; | |
293714c0 | 1323 | |
d5fd456c SK |
1324 | if (lc->config.info.lo_sizelimit > 0 && lc->config.info.lo_sizelimit < expected_size) |
1325 | expected_size = lc->config.info.lo_sizelimit; | |
293714c0 JM |
1326 | |
1327 | dev_fd = loopcxt_get_fd(lc); | |
01307ecf | 1328 | if (dev_fd < 0) { |
0bf03740 | 1329 | DBG(CXT, ul_debugobj(lc, "failed to get loop FD")); |
293714c0 | 1330 | return -errno; |
01307ecf | 1331 | } |
293714c0 | 1332 | |
01307ecf | 1333 | if (blkdev_get_size(dev_fd, (unsigned long long *) &size)) { |
0bf03740 | 1334 | DBG(CXT, ul_debugobj(lc, "failed to determine loopdev size")); |
293714c0 | 1335 | return -errno; |
01307ecf | 1336 | } |
293714c0 | 1337 | |
a7d5202b KZ |
1338 | /* It's block device, so, align to 512-byte sectors */ |
1339 | if (expected_size % 512) { | |
0bf03740 | 1340 | DBG(CXT, ul_debugobj(lc, "expected size misaligned to 512-byte sectors")); |
a7d5202b KZ |
1341 | expected_size = (expected_size >> 9) << 9; |
1342 | } | |
1343 | ||
293714c0 | 1344 | if (expected_size != size) { |
0bf03740 | 1345 | DBG(CXT, ul_debugobj(lc, "warning: loopdev and expected " |
9e930041 | 1346 | "size mismatch (%ju/%ju)", |
e3b6cb87 KZ |
1347 | size, expected_size)); |
1348 | ||
9fcc8936 | 1349 | if (loopcxt_ioctl_capacity(lc)) { |
293714c0 JM |
1350 | /* ioctl not available */ |
1351 | if (errno == ENOTTY || errno == EINVAL) | |
1352 | errno = ERANGE; | |
1353 | return -errno; | |
1354 | } | |
1355 | ||
1356 | if (blkdev_get_size(dev_fd, (unsigned long long *) &size)) | |
1357 | return -errno; | |
1358 | ||
01307ecf KZ |
1359 | if (expected_size != size) { |
1360 | errno = ERANGE; | |
0bf03740 | 1361 | DBG(CXT, ul_debugobj(lc, "failed to set loopdev size, " |
01307ecf KZ |
1362 | "size: %ju, expected: %ju", |
1363 | size, expected_size)); | |
1364 | return -errno; | |
1365 | } | |
293714c0 JM |
1366 | } |
1367 | ||
1368 | return 0; | |
1369 | } | |
1370 | ||
9d5424c2 | 1371 | |
10ee5932 | 1372 | /* |
bfd4e1f7 | 1373 | * @lc: context |
10ee5932 KZ |
1374 | * |
1375 | * Associate the current device (see loopcxt_{set,get}_device()) with | |
1376 | * a file (see loopcxt_set_backing_file()). | |
1377 | * | |
fd7f0718 KZ |
1378 | * The device is initialized read-write by default. If you want read-only |
1379 | * device then set LO_FLAGS_READ_ONLY by loopcxt_set_flags(). The LOOPDEV_FL_* | |
1380 | * flags are ignored and modified according to LO_FLAGS_*. | |
1381 | * | |
1382 | * If the device is already open by loopcxt_get_fd() then this setup device | |
1383 | * function will re-open the device to fix read/write mode. | |
1384 | * | |
1385 | * The device is also initialized read-only if the backing file is not | |
1386 | * possible to open read-write (e.g. read-only FS). | |
10ee5932 KZ |
1387 | * |
1388 | * Returns: <0 on error, 0 on success. | |
1389 | */ | |
1390 | int loopcxt_setup_device(struct loopdev_cxt *lc) | |
1391 | { | |
ced1142d KZ |
1392 | int file_fd, dev_fd; |
1393 | mode_t flags = O_CLOEXEC, mode = O_RDWR; | |
1328e0f7 | 1394 | int rc = -1, cnt = 0; |
2cde9865 | 1395 | int errsv = 0; |
d5fd456c | 1396 | int fallback = 0; |
10ee5932 KZ |
1397 | |
1398 | if (!lc || !*lc->device || !lc->filename) | |
1399 | return -EINVAL; | |
1400 | ||
0bf03740 | 1401 | DBG(SETUP, ul_debugobj(lc, "device setup requested")); |
aee31ddc | 1402 | |
10ee5932 KZ |
1403 | /* |
1404 | * Open backing file and device | |
1405 | */ | |
d5fd456c | 1406 | if (lc->config.info.lo_flags & LO_FLAGS_READ_ONLY) |
fd7f0718 | 1407 | mode = O_RDONLY; |
10ee5932 | 1408 | |
d53346ed AXH |
1409 | if (lc->config.info.lo_flags & LO_FLAGS_DIRECT_IO) |
1410 | flags |= O_DIRECT; | |
1411 | ||
1412 | if ((file_fd = open(lc->filename, mode | flags)) < 0) { | |
10ee5932 | 1413 | if (mode != O_RDONLY && (errno == EROFS || errno == EACCES)) |
d53346ed | 1414 | file_fd = open(lc->filename, (mode = O_RDONLY) | flags); |
10ee5932 | 1415 | |
aee31ddc | 1416 | if (file_fd < 0) { |
0bf03740 | 1417 | DBG(SETUP, ul_debugobj(lc, "open backing file failed: %m")); |
10ee5932 | 1418 | return -errno; |
aee31ddc | 1419 | } |
10ee5932 | 1420 | } |
0bf03740 | 1421 | DBG(SETUP, ul_debugobj(lc, "backing file open: OK")); |
10ee5932 | 1422 | |
ced1142d | 1423 | if (mode == O_RDONLY) |
d5fd456c | 1424 | lc->config.info.lo_flags |= LO_FLAGS_READ_ONLY; /* kernel loopdev mode */ |
ced1142d | 1425 | else |
d5fd456c | 1426 | lc->config.info.lo_flags &= ~LO_FLAGS_READ_ONLY; |
10ee5932 | 1427 | |
663bf040 KZ |
1428 | do { |
1429 | errno = 0; | |
ced1142d KZ |
1430 | |
1431 | /* For the ioctls, it's enough to use O_RDONLY, but udevd | |
1432 | * monitor devices by inotify, and udevd needs IN_CLOSE_WRITE | |
1433 | * event to trigger probing of the new device. | |
1434 | * | |
1435 | * The mode used for the device does not have to match the mode | |
1436 | * used for the backing file. | |
1437 | */ | |
1438 | dev_fd = __loopcxt_get_fd(lc, O_RDWR); | |
663bf040 KZ |
1439 | if (dev_fd >= 0 || lc->control_ok == 0) |
1440 | break; | |
1441 | if (errno != EACCES && errno != ENOENT) | |
1442 | break; | |
1443 | /* We have permissions to open /dev/loop-control, but open | |
1444 | * /dev/loopN failed with EACCES, it's probably because udevd | |
1445 | * does not applied chown yet. Let's wait a moment. */ | |
1446 | xusleep(25000); | |
1447 | } while (cnt++ < 16); | |
1448 | ||
10ee5932 KZ |
1449 | if (dev_fd < 0) { |
1450 | rc = -errno; | |
1451 | goto err; | |
1452 | } | |
1453 | ||
0bf03740 | 1454 | DBG(SETUP, ul_debugobj(lc, "device open: OK")); |
d356c5d2 | 1455 | |
a61955ba KZ |
1456 | /* |
1457 | * Atomic way to configure all by one ioctl call | |
1458 | * -- since Linux v5.8-rc1, commit 3448914e8cc550ba792d4ccc74471d1ca4293aae | |
1459 | */ | |
d5fd456c | 1460 | lc->config.fd = file_fd; |
854abba0 HE |
1461 | if (lc->blocksize > 0) |
1462 | lc->config.block_size = lc->blocksize; | |
9d5424c2 KZ |
1463 | |
1464 | rc = repeat_on_eagain( ioctl(dev_fd, LOOP_CONFIGURE, &lc->config) ); | |
1465 | if (rc != 0) { | |
2cde9865 | 1466 | errsv = errno; |
f6385a6a | 1467 | if (errno != EINVAL && errno != ENOTTY && errno != ENOSYS) { |
d5fd456c SK |
1468 | DBG(SETUP, ul_debugobj(lc, "LOOP_CONFIGURE failed: %m")); |
1469 | goto err; | |
1470 | } | |
1471 | fallback = 1; | |
a61955ba | 1472 | } else { |
d5fd456c | 1473 | DBG(SETUP, ul_debugobj(lc, "LOOP_CONFIGURE: OK")); |
75d239ff KZ |
1474 | } |
1475 | ||
a61955ba KZ |
1476 | /* |
1477 | * Old deprecated way; first assign backing file FD and then in the | |
1478 | * second step set loop device properties. | |
1479 | */ | |
d5fd456c | 1480 | if (fallback) { |
d5fd456c SK |
1481 | if (ioctl(dev_fd, LOOP_SET_FD, file_fd) < 0) { |
1482 | rc = -errno; | |
1483 | errsv = errno; | |
1484 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_FD failed: %m")); | |
1485 | goto err; | |
1486 | } | |
d356c5d2 | 1487 | |
d5fd456c SK |
1488 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_FD: OK")); |
1489 | ||
1490 | if (lc->blocksize > 0 | |
1491 | && (rc = loopcxt_ioctl_blocksize(lc, lc->blocksize)) < 0) { | |
1492 | errsv = -rc; | |
1493 | goto err; | |
1494 | } | |
1495 | ||
1328e0f7 KZ |
1496 | if ((rc = loopcxt_ioctl_status(lc)) < 0) { |
1497 | errsv = -rc; | |
d5fd456c SK |
1498 | goto err; |
1499 | } | |
d5fd456c | 1500 | } |
d356c5d2 | 1501 | |
293714c0 JM |
1502 | if ((rc = loopcxt_check_size(lc, file_fd))) |
1503 | goto err; | |
1504 | ||
1505 | close(file_fd); | |
293714c0 | 1506 | |
d5fd456c | 1507 | memset(&lc->config, 0, sizeof(lc->config)); |
10ee5932 | 1508 | lc->has_info = 0; |
6c224de1 | 1509 | lc->info_failed = 0; |
10ee5932 | 1510 | |
0bf03740 | 1511 | DBG(SETUP, ul_debugobj(lc, "success [rc=0]")); |
10ee5932 KZ |
1512 | return 0; |
1513 | err: | |
1514 | if (file_fd >= 0) | |
1515 | close(file_fd); | |
f7e21185 | 1516 | if (dev_fd >= 0 && rc != -EBUSY) |
10ee5932 | 1517 | ioctl(dev_fd, LOOP_CLR_FD, 0); |
2cde9865 KZ |
1518 | if (errsv) |
1519 | errno = errsv; | |
10ee5932 | 1520 | |
0bf03740 | 1521 | DBG(SETUP, ul_debugobj(lc, "failed [rc=%d]", rc)); |
10ee5932 KZ |
1522 | return rc; |
1523 | } | |
1524 | ||
9d5424c2 | 1525 | |
bfd4e1f7 SB |
1526 | /* |
1527 | * @lc: context | |
1528 | * | |
1529 | * Update status of the current device (see loopcxt_{set,get}_device()). | |
1530 | * | |
1531 | * Note that once initialized, kernel accepts only selected changes: | |
1532 | * LO_FLAGS_AUTOCLEAR and LO_FLAGS_PARTSCAN | |
1533 | * For more see linux/drivers/block/loop.c:loop_set_status() | |
1534 | * | |
1535 | * Returns: <0 on error, 0 on success. | |
1536 | */ | |
9fcc8936 | 1537 | int loopcxt_ioctl_status(struct loopdev_cxt *lc) |
bfd4e1f7 | 1538 | { |
9d5424c2 | 1539 | int dev_fd, rc; |
bfd4e1f7 SB |
1540 | |
1541 | errno = 0; | |
1542 | dev_fd = loopcxt_get_fd(lc); | |
1543 | ||
9d5424c2 KZ |
1544 | if (dev_fd < 0) |
1545 | return -errno; | |
bfd4e1f7 | 1546 | |
9d5424c2 | 1547 | DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_STATUS64")); |
0ae7bb11 | 1548 | |
9d5424c2 KZ |
1549 | rc = repeat_on_eagain( ioctl(dev_fd, LOOP_SET_STATUS64, &lc->config.info) ); |
1550 | if (rc != 0) { | |
bfd4e1f7 SB |
1551 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64 failed: %m")); |
1552 | return rc; | |
1553 | } | |
1554 | ||
1555 | DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64: OK")); | |
1556 | return 0; | |
1557 | } | |
1558 | ||
9fcc8936 | 1559 | int loopcxt_ioctl_capacity(struct loopdev_cxt *lc) |
293714c0 | 1560 | { |
9d5424c2 | 1561 | int rc, fd = loopcxt_get_fd(lc); |
293714c0 JM |
1562 | |
1563 | if (fd < 0) | |
1564 | return -EINVAL; | |
1565 | ||
9d5424c2 KZ |
1566 | DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_CAPACITY")); |
1567 | ||
293714c0 | 1568 | /* Kernels prior to v2.6.30 don't support this ioctl */ |
9d5424c2 KZ |
1569 | rc = repeat_on_eagain( ioctl(fd, LOOP_SET_CAPACITY, 0) ); |
1570 | if (rc != 0) { | |
0bf03740 | 1571 | DBG(CXT, ul_debugobj(lc, "LOOP_SET_CAPACITY failed: %m")); |
293714c0 JM |
1572 | return rc; |
1573 | } | |
1574 | ||
0bf03740 | 1575 | DBG(CXT, ul_debugobj(lc, "capacity set")); |
293714c0 JM |
1576 | return 0; |
1577 | } | |
1578 | ||
9fcc8936 | 1579 | int loopcxt_ioctl_dio(struct loopdev_cxt *lc, unsigned long use_dio) |
64c3bb3c | 1580 | { |
9d5424c2 | 1581 | int rc, fd = loopcxt_get_fd(lc); |
64c3bb3c ML |
1582 | |
1583 | if (fd < 0) | |
1584 | return -EINVAL; | |
1585 | ||
9d5424c2 KZ |
1586 | DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_DIRECT_IO")); |
1587 | ||
64c3bb3c | 1588 | /* Kernels prior to v4.4 don't support this ioctl */ |
9d5424c2 KZ |
1589 | rc = repeat_on_eagain( ioctl(fd, LOOP_SET_DIRECT_IO, use_dio) ); |
1590 | if (rc != 0) { | |
64c3bb3c ML |
1591 | DBG(CXT, ul_debugobj(lc, "LOOP_SET_DIRECT_IO failed: %m")); |
1592 | return rc; | |
1593 | } | |
1594 | ||
1595 | DBG(CXT, ul_debugobj(lc, "direct io set")); | |
1596 | return 0; | |
1597 | } | |
1598 | ||
c4e60bc0 KZ |
1599 | /* |
1600 | * Kernel uses "unsigned long" as ioctl arg, but we use u64 for all sizes to | |
1601 | * keep loopdev internal API simple. | |
1602 | */ | |
9fcc8936 | 1603 | int loopcxt_ioctl_blocksize(struct loopdev_cxt *lc, uint64_t blocksize) |
a1a41597 | 1604 | { |
9d5424c2 | 1605 | int rc, fd = loopcxt_get_fd(lc); |
a1a41597 SB |
1606 | |
1607 | if (fd < 0) | |
1608 | return -EINVAL; | |
1609 | ||
9d5424c2 KZ |
1610 | DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_BLOCK_SIZE")); |
1611 | ||
1612 | rc = repeat_on_eagain( | |
1613 | ioctl(fd, LOOP_SET_BLOCK_SIZE, (unsigned long) blocksize) ); | |
1614 | if (rc != 0) { | |
1615 | DBG(CXT, ul_debugobj(lc, "LOOP_SET_BLOCK_SIZE failed: %m")); | |
1616 | return rc; | |
1617 | } | |
a1a41597 SB |
1618 | |
1619 | DBG(CXT, ul_debugobj(lc, "logical block size set")); | |
1620 | return 0; | |
1621 | } | |
1622 | ||
10ee5932 KZ |
1623 | int loopcxt_delete_device(struct loopdev_cxt *lc) |
1624 | { | |
9d5424c2 | 1625 | int rc, fd = loopcxt_get_fd(lc); |
10ee5932 KZ |
1626 | |
1627 | if (fd < 0) | |
1628 | return -EINVAL; | |
1629 | ||
9d5424c2 KZ |
1630 | DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_CLR_FD")); |
1631 | ||
1632 | rc = repeat_on_eagain( ioctl(fd, LOOP_CLR_FD, 0) ); | |
1633 | if (rc != 0) { | |
0bf03740 | 1634 | DBG(CXT, ul_debugobj(lc, "LOOP_CLR_FD failed: %m")); |
9d5424c2 | 1635 | return rc; |
aee31ddc KZ |
1636 | } |
1637 | ||
0bf03740 | 1638 | DBG(CXT, ul_debugobj(lc, "device removed")); |
10ee5932 KZ |
1639 | return 0; |
1640 | } | |
1641 | ||
3cb2413b KZ |
1642 | int loopcxt_add_device(struct loopdev_cxt *lc) |
1643 | { | |
1644 | int rc = -EINVAL; | |
1645 | int ctl, nr = -1; | |
1646 | const char *p, *dev = loopcxt_get_device(lc); | |
1647 | ||
1648 | if (!dev) | |
1649 | goto done; | |
1650 | ||
1651 | if (!(lc->flags & LOOPDEV_FL_CONTROL)) { | |
1652 | rc = -ENOSYS; | |
1653 | goto done; | |
1654 | } | |
1655 | ||
1656 | p = strrchr(dev, '/'); | |
1657 | if (!p || (sscanf(p, "/loop%d", &nr) != 1 && sscanf(p, "/%d", &nr) != 1) | |
1658 | || nr < 0) | |
1659 | goto done; | |
1660 | ||
1661 | ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); | |
1662 | if (ctl >= 0) { | |
0bf03740 | 1663 | DBG(CXT, ul_debugobj(lc, "add_device %d", nr)); |
3cb2413b KZ |
1664 | rc = ioctl(ctl, LOOP_CTL_ADD, nr); |
1665 | close(ctl); | |
1666 | } | |
663bf040 | 1667 | lc->control_ok = rc >= 0 ? 1 : 0; |
3cb2413b | 1668 | done: |
0bf03740 | 1669 | DBG(CXT, ul_debugobj(lc, "add_device done [rc=%d]", rc)); |
3cb2413b KZ |
1670 | return rc; |
1671 | } | |
1672 | ||
59d749c3 KZ |
1673 | /* |
1674 | * Note that LOOP_CTL_GET_FREE ioctl is supported since kernel 3.1. In older | |
1675 | * kernels we have to check all loop devices to found unused one. | |
1676 | * | |
1677 | * See kernel commit 770fe30a46a12b6fb6b63fbe1737654d28e8484. | |
3c540264 TW |
1678 | * |
1679 | * Returns: 0 = success, < 0 error | |
59d749c3 | 1680 | */ |
10ee5932 KZ |
1681 | int loopcxt_find_unused(struct loopdev_cxt *lc) |
1682 | { | |
0b14bf7a | 1683 | int rc = -1; |
10ee5932 | 1684 | |
0bf03740 | 1685 | DBG(CXT, ul_debugobj(lc, "find_unused requested")); |
aee31ddc | 1686 | |
0b14bf7a | 1687 | if (lc->flags & LOOPDEV_FL_CONTROL) { |
9a94b634 KZ |
1688 | int ctl; |
1689 | ||
1690 | DBG(CXT, ul_debugobj(lc, "using loop-control")); | |
10ee5932 | 1691 | |
9a94b634 | 1692 | ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); |
0b14bf7a KZ |
1693 | if (ctl >= 0) |
1694 | rc = ioctl(ctl, LOOP_CTL_GET_FREE); | |
3c540264 TW |
1695 | else |
1696 | rc = -errno; | |
0b14bf7a KZ |
1697 | if (rc >= 0) { |
1698 | char name[16]; | |
1699 | snprintf(name, sizeof(name), "loop%d", rc); | |
1700 | ||
1701 | rc = loopiter_set_device(lc, name); | |
1702 | } | |
663bf040 | 1703 | lc->control_ok = ctl >= 0 && rc == 0 ? 1 : 0; |
0b14bf7a KZ |
1704 | if (ctl >= 0) |
1705 | close(ctl); | |
0bf03740 | 1706 | DBG(CXT, ul_debugobj(lc, "find_unused by loop-control [rc=%d]", rc)); |
0b14bf7a KZ |
1707 | } |
1708 | ||
1709 | if (rc < 0) { | |
9a94b634 | 1710 | DBG(CXT, ul_debugobj(lc, "using loop scan")); |
0b14bf7a KZ |
1711 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_FREE); |
1712 | if (rc) | |
1713 | return rc; | |
10ee5932 | 1714 | |
0b14bf7a KZ |
1715 | rc = loopcxt_next(lc); |
1716 | loopcxt_deinit_iterator(lc); | |
0bf03740 | 1717 | DBG(CXT, ul_debugobj(lc, "find_unused by scan [rc=%d]", rc)); |
3c540264 TW |
1718 | if (rc) |
1719 | return -ENOENT; | |
0b14bf7a | 1720 | } |
10ee5932 KZ |
1721 | return rc; |
1722 | } | |
1723 | ||
1724 | ||
1725 | ||
1726 | /* | |
1727 | * Return: TRUE/FALSE | |
1728 | */ | |
1729 | int loopdev_is_autoclear(const char *device) | |
1730 | { | |
1731 | struct loopdev_cxt lc; | |
1732 | int rc; | |
1733 | ||
1734 | if (!device) | |
1735 | return 0; | |
1736 | ||
defa0710 KZ |
1737 | rc = loopcxt_init(&lc, 0); |
1738 | if (!rc) | |
1739 | rc = loopcxt_set_device(&lc, device); | |
1740 | if (!rc) | |
1741 | rc = loopcxt_is_autoclear(&lc); | |
10ee5932 | 1742 | |
defa0710 | 1743 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1744 | return rc; |
1745 | } | |
1746 | ||
1747 | char *loopdev_get_backing_file(const char *device) | |
1748 | { | |
1749 | struct loopdev_cxt lc; | |
defa0710 | 1750 | char *res = NULL; |
10ee5932 KZ |
1751 | |
1752 | if (!device) | |
1753 | return NULL; | |
defa0710 KZ |
1754 | if (loopcxt_init(&lc, 0)) |
1755 | return NULL; | |
1756 | if (loopcxt_set_device(&lc, device) == 0) | |
1757 | res = loopcxt_get_backing_file(&lc); | |
10ee5932 | 1758 | |
10ee5932 | 1759 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1760 | return res; |
1761 | } | |
1762 | ||
af5efcd8 TW |
1763 | /* |
1764 | * Returns: TRUE/FALSE | |
1765 | */ | |
14bb8e3c KZ |
1766 | int loopdev_has_backing_file(const char *device) |
1767 | { | |
1768 | char *tmp = loopdev_get_backing_file(device); | |
1769 | ||
1770 | if (tmp) { | |
1771 | free(tmp); | |
1772 | return 1; | |
1773 | } | |
1774 | return 0; | |
1775 | } | |
1776 | ||
10ee5932 KZ |
1777 | /* |
1778 | * Returns: TRUE/FALSE | |
1779 | */ | |
1780 | int loopdev_is_used(const char *device, const char *filename, | |
74a4705a | 1781 | uint64_t offset, uint64_t sizelimit, int flags) |
10ee5932 KZ |
1782 | { |
1783 | struct loopdev_cxt lc; | |
6c224de1 | 1784 | struct stat st; |
10ee5932 KZ |
1785 | int rc = 0; |
1786 | ||
8b470b20 | 1787 | if (!device || !filename) |
10ee5932 KZ |
1788 | return 0; |
1789 | ||
defa0710 KZ |
1790 | rc = loopcxt_init(&lc, 0); |
1791 | if (!rc) | |
1792 | rc = loopcxt_set_device(&lc, device); | |
1793 | if (rc) | |
1794 | return rc; | |
10ee5932 | 1795 | |
6c224de1 | 1796 | rc = !stat(filename, &st); |
74a4705a | 1797 | rc = loopcxt_is_used(&lc, rc ? &st : NULL, filename, offset, sizelimit, flags); |
10ee5932 | 1798 | |
10ee5932 | 1799 | loopcxt_deinit(&lc); |
10ee5932 KZ |
1800 | return rc; |
1801 | } | |
1802 | ||
af5efcd8 TW |
1803 | /* |
1804 | * Returns: 0 = success, < 0 error | |
1805 | */ | |
10ee5932 KZ |
1806 | int loopdev_delete(const char *device) |
1807 | { | |
1808 | struct loopdev_cxt lc; | |
1809 | int rc; | |
1810 | ||
8b470b20 KZ |
1811 | if (!device) |
1812 | return -EINVAL; | |
1813 | ||
defa0710 KZ |
1814 | rc = loopcxt_init(&lc, 0); |
1815 | if (!rc) | |
1816 | rc = loopcxt_set_device(&lc, device); | |
10ee5932 KZ |
1817 | if (!rc) |
1818 | rc = loopcxt_delete_device(&lc); | |
1819 | loopcxt_deinit(&lc); | |
1820 | return rc; | |
1821 | } | |
1822 | ||
1823 | /* | |
1824 | * Returns: 0 = success, < 0 error, 1 not found | |
1825 | */ | |
1826 | int loopcxt_find_by_backing_file(struct loopdev_cxt *lc, const char *filename, | |
74a4705a | 1827 | uint64_t offset, uint64_t sizelimit, int flags) |
10ee5932 | 1828 | { |
6c224de1 KZ |
1829 | int rc, hasst; |
1830 | struct stat st; | |
10ee5932 KZ |
1831 | |
1832 | if (!filename) | |
1833 | return -EINVAL; | |
1834 | ||
6c224de1 KZ |
1835 | hasst = !stat(filename, &st); |
1836 | ||
10ee5932 KZ |
1837 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); |
1838 | if (rc) | |
1839 | return rc; | |
1840 | ||
6c224de1 | 1841 | while ((rc = loopcxt_next(lc)) == 0) { |
10ee5932 | 1842 | |
6c224de1 | 1843 | if (loopcxt_is_used(lc, hasst ? &st : NULL, |
74a4705a | 1844 | filename, offset, sizelimit, flags)) |
6c224de1 | 1845 | break; |
10ee5932 KZ |
1846 | } |
1847 | ||
1848 | loopcxt_deinit_iterator(lc); | |
1849 | return rc; | |
1850 | } | |
1851 | ||
211e1d46 | 1852 | /* |
dff7e160 | 1853 | * Returns: 0 = not found, < 0 error, 1 found, 2 found full size and offset match |
211e1d46 | 1854 | */ |
c444a71b | 1855 | int loopcxt_find_overlap(struct loopdev_cxt *lc, const char *filename, |
211e1d46 SB |
1856 | uint64_t offset, uint64_t sizelimit) |
1857 | { | |
1858 | int rc, hasst; | |
1859 | struct stat st; | |
1860 | ||
1861 | if (!filename) | |
1862 | return -EINVAL; | |
1863 | ||
9a94b634 | 1864 | DBG(CXT, ul_debugobj(lc, "find_overlap requested")); |
211e1d46 SB |
1865 | hasst = !stat(filename, &st); |
1866 | ||
1867 | rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); | |
1868 | if (rc) | |
1869 | return rc; | |
1870 | ||
1871 | while ((rc = loopcxt_next(lc)) == 0) { | |
1872 | uint64_t lc_sizelimit, lc_offset; | |
1873 | ||
1874 | rc = loopcxt_is_used(lc, hasst ? &st : NULL, | |
1875 | filename, offset, sizelimit, 0); | |
562990b5 JK |
1876 | /* |
1877 | * Either the loopdev is unused or we've got an error which can | |
1878 | * happen when we are racing with device autoclear. Just ignore | |
1879 | * this loopdev... | |
1880 | */ | |
1881 | if (rc <= 0) | |
1882 | continue; | |
c444a71b | 1883 | |
211e1d46 SB |
1884 | DBG(CXT, ul_debugobj(lc, "found %s backed by %s", |
1885 | loopcxt_get_device(lc), filename)); | |
c444a71b | 1886 | |
211e1d46 SB |
1887 | rc = loopcxt_get_offset(lc, &lc_offset); |
1888 | if (rc) { | |
1889 | DBG(CXT, ul_debugobj(lc, "failed to get offset for device %s", | |
1890 | loopcxt_get_device(lc))); | |
562990b5 | 1891 | continue; |
211e1d46 SB |
1892 | } |
1893 | rc = loopcxt_get_sizelimit(lc, &lc_sizelimit); | |
1894 | if (rc) { | |
1895 | DBG(CXT, ul_debugobj(lc, "failed to get sizelimit for device %s", | |
1896 | loopcxt_get_device(lc))); | |
562990b5 | 1897 | continue; |
211e1d46 SB |
1898 | } |
1899 | ||
dff7e160 KZ |
1900 | /* full match */ |
1901 | if (lc_sizelimit == sizelimit && lc_offset == offset) { | |
1902 | DBG(CXT, ul_debugobj(lc, "overlapping loop device %s (full match)", | |
1903 | loopcxt_get_device(lc))); | |
1904 | rc = 2; | |
1905 | goto found; | |
1906 | } | |
1907 | ||
1908 | /* overlap */ | |
211e1d46 SB |
1909 | if (lc_sizelimit != 0 && offset >= lc_offset + lc_sizelimit) |
1910 | continue; | |
1911 | if (sizelimit != 0 && offset + sizelimit <= lc_offset) | |
1912 | continue; | |
dff7e160 | 1913 | |
211e1d46 SB |
1914 | DBG(CXT, ul_debugobj(lc, "overlapping loop device %s", |
1915 | loopcxt_get_device(lc))); | |
dff7e160 KZ |
1916 | rc = 1; |
1917 | goto found; | |
211e1d46 | 1918 | } |
dff7e160 KZ |
1919 | |
1920 | if (rc == 1) | |
1921 | rc = 0; /* not found */ | |
1922 | found: | |
211e1d46 | 1923 | loopcxt_deinit_iterator(lc); |
9a94b634 | 1924 | DBG(CXT, ul_debugobj(lc, "find_overlap done [rc=%d]", rc)); |
211e1d46 SB |
1925 | return rc; |
1926 | } | |
1927 | ||
10ee5932 KZ |
1928 | /* |
1929 | * Returns allocated string with device name | |
1930 | */ | |
74a4705a | 1931 | char *loopdev_find_by_backing_file(const char *filename, uint64_t offset, uint64_t sizelimit, int flags) |
10ee5932 KZ |
1932 | { |
1933 | struct loopdev_cxt lc; | |
1934 | char *res = NULL; | |
1935 | ||
1936 | if (!filename) | |
1937 | return NULL; | |
1938 | ||
defa0710 KZ |
1939 | if (loopcxt_init(&lc, 0)) |
1940 | return NULL; | |
74a4705a | 1941 | if (loopcxt_find_by_backing_file(&lc, filename, offset, sizelimit, flags) == 0) |
10ee5932 KZ |
1942 | res = loopcxt_strdup_device(&lc); |
1943 | loopcxt_deinit(&lc); | |
1944 | ||
1945 | return res; | |
1946 | } | |
1947 | ||
d5688130 KZ |
1948 | /* |
1949 | * Returns number of loop devices associated with @file, if only one loop | |
11026083 | 1950 | * device is associated with the given @filename and @loopdev is not NULL then |
d5688130 KZ |
1951 | * @loopdev returns name of the device. |
1952 | */ | |
1953 | int loopdev_count_by_backing_file(const char *filename, char **loopdev) | |
1954 | { | |
1955 | struct loopdev_cxt lc; | |
defa0710 | 1956 | int count = 0, rc; |
d5688130 KZ |
1957 | |
1958 | if (!filename) | |
1959 | return -1; | |
1960 | ||
defa0710 KZ |
1961 | rc = loopcxt_init(&lc, 0); |
1962 | if (rc) | |
1963 | return rc; | |
d5688130 KZ |
1964 | if (loopcxt_init_iterator(&lc, LOOPITER_FL_USED)) |
1965 | return -1; | |
1966 | ||
1967 | while(loopcxt_next(&lc) == 0) { | |
1968 | char *backing = loopcxt_get_backing_file(&lc); | |
1969 | ||
ad296391 | 1970 | if (!backing || strcmp(backing, filename) != 0) { |
d5688130 KZ |
1971 | free(backing); |
1972 | continue; | |
1973 | } | |
1974 | ||
1975 | free(backing); | |
1976 | if (loopdev && count == 0) | |
1977 | *loopdev = loopcxt_strdup_device(&lc); | |
1978 | count++; | |
1979 | } | |
1980 | ||
1981 | loopcxt_deinit(&lc); | |
1982 | ||
1983 | if (loopdev && count > 1) { | |
1984 | free(*loopdev); | |
1985 | *loopdev = NULL; | |
1986 | } | |
1987 | return count; | |
1988 | } | |
1989 | ||
d4423cce KZ |
1990 | #ifdef TEST_PROGRAM_LOOPDEV |
1991 | int main(int argc, char *argv[]) | |
1992 | { | |
1993 | if (argc < 2) | |
1994 | goto usage; | |
1995 | ||
1996 | if (strcmp(argv[1], "--is-loopdev") == 0 && argc == 3) | |
1997 | printf("%s: %s\n", argv[2], is_loopdev(argv[2]) ? "OK" : "FAIL"); | |
1998 | else | |
1999 | goto usage; | |
2000 | ||
2001 | return EXIT_SUCCESS; | |
2002 | usage: | |
2003 | fprintf(stderr, "usage: %1$s --is-loopdev <dev>\n", | |
2004 | program_invocation_short_name); | |
2005 | return EXIT_FAILURE; | |
2006 | } | |
2007 | #endif | |
2008 |