2 * devname - search for device name
4 * Copyright (C) 2004 Jana Saout <jana@saout.de>
5 * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org>
6 * Copyright (C) 2009-2021 Red Hat, Inc. All rights reserved.
7 * Copyright (C) 2009-2021 Milan Broz
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version 2
12 * of the License, or (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
32 #include <sys/types.h>
33 #ifdef HAVE_SYS_SYSMACROS_H
34 # include <sys/sysmacros.h> /* for major, minor */
38 static char *__lookup_dev(char *path, dev_t dev, int dir_level, const int max_level)
47 /* Ignore strange nested directories */
48 if (dir_level > max_level)
51 path[PATH_MAX - 1] = '\0';
52 ptr = path + strlen(path);
55 space = PATH_MAX - (ptr - path);
61 while((entry = readdir(dir))) {
62 if (entry->d_name[0] == '.' ||
63 !strncmp(entry->d_name, "..", 2))
67 (!strcmp(entry->d_name, "shm") ||
68 !strcmp(entry->d_name, "fd") ||
69 !strcmp(entry->d_name, "char") ||
70 !strcmp(entry->d_name, "pts")))
73 strncpy(ptr, entry->d_name, space);
74 if (stat(path, &st) < 0)
77 if (S_ISDIR(st.st_mode)) {
78 result = __lookup_dev(path, dev, dir_level + 1, max_level);
81 } else if (S_ISBLK(st.st_mode)) {
82 /* workaround: ignore dm-X devices, these are internal kernel names */
83 if (dir_level == 0 && dm_is_dm_kernel_name(entry->d_name))
85 if (st.st_rdev == dev) {
86 result = strdup(path);
97 * Non-udev systemd need to scan for device here.
99 static char *lookup_dev_old(int major, int minor)
102 char *result = NULL, buf[PATH_MAX + 1];
104 dev = makedev(major, minor);
105 strncpy(buf, "/dev", PATH_MAX);
106 buf[PATH_MAX] = '\0';
108 /* First try low level device */
109 if ((result = __lookup_dev(buf, dev, 0, 0)))
112 /* If it is dm, try DM dir */
113 if (dm_is_dm_device(major)) {
114 strncpy(buf, dm_get_dir(), PATH_MAX);
115 if ((result = __lookup_dev(buf, dev, 0, 0)))
119 strncpy(buf, "/dev", PATH_MAX);
120 return __lookup_dev(buf, dev, 0, 4);
124 * Returns string pointing to device in /dev according to "major:minor" dev_id
126 char *crypt_lookup_dev(const char *dev_id)
129 char link[PATH_MAX], path[PATH_MAX], *devname, *devpath = NULL;
133 if (sscanf(dev_id, "%d:%d", &major, &minor) != 2)
136 if (snprintf(path, sizeof(path), "/sys/dev/block/%s", dev_id) < 0)
139 len = readlink(path, link, sizeof(link) - 1);
141 /* Without /sys use old scan */
142 if (stat("/sys/dev/block", &st) < 0)
143 return lookup_dev_old(major, minor);
148 devname = strrchr(link, '/');
153 if (dm_is_dm_kernel_name(devname))
154 devpath = dm_device_path("/dev/mapper/", major, minor);
155 else if (snprintf(path, sizeof(path), "/dev/%s", devname) > 0)
156 devpath = strdup(path);
159 * Check that path is correct.
161 if (devpath && ((stat(devpath, &st) < 0) ||
162 !S_ISBLK(st.st_mode) ||
163 (st.st_rdev != makedev(major, minor)))) {
165 /* Should never happen unless user mangles with dev nodes. */
166 return lookup_dev_old(major, minor);
172 static int _read_uint64(const char *sysfs_path, uint64_t *value)
177 if ((fd = open(sysfs_path, O_RDONLY)) < 0)
179 r = read(fd, tmp, sizeof(tmp));
185 if (sscanf(tmp, "%" PRIu64, value) != 1)
191 static int _sysfs_get_uint64(int major, int minor, uint64_t *value, const char *attr)
195 if (snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/%s",
196 major, minor, attr) < 0)
199 return _read_uint64(path, value);
202 static int _path_get_uint64(const char *sysfs_path, uint64_t *value, const char *attr)
206 if (snprintf(path, sizeof(path), "%s/%s",
207 sysfs_path, attr) < 0)
210 return _read_uint64(path, value);
213 int crypt_dev_is_rotational(int major, int minor)
217 if (!_sysfs_get_uint64(major, minor, &val, "queue/rotational"))
218 return 1; /* if failed, expect rotational disk */
223 int crypt_dev_is_partition(const char *dev_path)
228 if (stat(dev_path, &st) < 0)
231 if (!S_ISBLK(st.st_mode))
234 if (!_sysfs_get_uint64(major(st.st_rdev), minor(st.st_rdev),
241 uint64_t crypt_dev_partition_offset(const char *dev_path)
246 if (!crypt_dev_is_partition(dev_path))
249 if (stat(dev_path, &st) < 0)
252 if (!_sysfs_get_uint64(major(st.st_rdev), minor(st.st_rdev),
259 /* Try to find partition which match offset and size on top level device */
260 char *crypt_get_partition_device(const char *dev_path, uint64_t offset, uint64_t size)
262 char link[PATH_MAX], path[PATH_MAX], part_path[PATH_MAX], *devname;
267 struct dirent *entry;
269 uint64_t part_offset, part_size;
271 if (stat(dev_path, &st) < 0)
274 if (!S_ISBLK(st.st_mode))
277 if (snprintf(path, sizeof(path), "/sys/dev/block/%d:%d",
278 major(st.st_rdev), minor(st.st_rdev)) < 0)
285 len = readlink(path, link, sizeof(link) - 1);
291 /* Get top level disk name for sysfs search */
293 devname = strrchr(link, '/');
300 /* DM devices do not use kernel partitions. */
301 if (dm_is_dm_kernel_name(devname)) {
306 devname_len = strlen(devname);
307 while((entry = readdir(dir))) {
308 if (strncmp(entry->d_name, devname, devname_len))
311 if (snprintf(part_path, sizeof(part_path), "%s/%s",
312 path, entry->d_name) < 0)
315 if (stat(part_path, &st) < 0)
318 if (S_ISDIR(st.st_mode)) {
319 if (!_path_get_uint64(part_path, &part_offset, "start") ||
320 !_path_get_uint64(part_path, &part_size, "size"))
322 if (part_offset == offset && part_size == size &&
323 snprintf(part_path, sizeof(part_path), "/dev/%s",
324 entry->d_name) > 0) {
325 result = strdup(part_path);
335 /* Try to find base device from partition */
336 char *crypt_get_base_device(const char *dev_path)
338 char link[PATH_MAX], path[PATH_MAX], part_path[PATH_MAX], *devname;
342 if (!crypt_dev_is_partition(dev_path))
345 if (stat(dev_path, &st) < 0)
348 if (snprintf(path, sizeof(path), "/sys/dev/block/%d:%d",
349 major(st.st_rdev), minor(st.st_rdev)) < 0)
352 len = readlink(path, link, sizeof(link) - 1);
356 /* Get top level disk name for sysfs search */
358 devname = strrchr(link, '/');
362 devname = strrchr(link, '/');
367 if (dm_is_dm_kernel_name(devname))
370 if (snprintf(part_path, sizeof(part_path), "/dev/%s", devname) < 0)
373 return strdup(part_path);
376 int lookup_by_disk_id(const char *dm_uuid)
378 struct dirent *entry;
380 int r = 0; /* not found */
381 DIR *dir = opendir("/dev/disk/by-id");
384 /* map ENOTDIR to ENOENT we'll handle both errors same */
385 return errno == ENOTDIR ? -ENOENT : -errno;
387 while ((entry = readdir(dir))) {
388 if (entry->d_name[0] == '.' ||
389 !strncmp(entry->d_name, "..", 2))
392 if (fstatat(dirfd(dir), entry->d_name, &st, AT_SYMLINK_NOFOLLOW)) {
397 if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode))
400 if (!strncmp(entry->d_name, dm_uuid, strlen(dm_uuid))) {
411 int lookup_by_sysfs_uuid_field(const char *dm_uuid, size_t max_len)
413 struct dirent *entry;
414 char subpath[PATH_MAX], uuid[max_len];
417 int fd, len, r = 0; /* not found */
418 DIR *dir = opendir("/sys/block/");
421 /* map ENOTDIR to ENOENT we'll handle both errors same */
422 return errno == ENOTDIR ? -ENOENT : -errno;
424 while (r != 1 && (entry = readdir(dir))) {
425 if (entry->d_name[0] == '.' ||
426 !strncmp(entry->d_name, "..", 2))
429 len = snprintf(subpath, PATH_MAX, "%s/%s", entry->d_name, "dm/uuid");
430 if (len < 0 || len >= PATH_MAX) {
435 /* looking for dm-X/dm/uuid file, symlinks are fine */
436 fd = openat(dirfd(dir), subpath, O_RDONLY | O_CLOEXEC);
440 if (fstat(fd, &st) || !S_ISREG(st.st_mode)) {
445 /* reads binary data */
446 s = read_buffer(fd, uuid, max_len - 1);
449 if (!strncmp(uuid, dm_uuid, strlen(dm_uuid)))