2 * devname - search for device name
4 * Copyright (C) 2004, Christophe Saout <christophe@saout.de>
5 * Copyright (C) 2004-2007, Clemens Fruhwirth <clemens@endorphin.org>
6 * Copyright (C) 2009-2011, Red Hat, Inc. All rights reserved.
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * version 2 as published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 #include <sys/types.h>
31 static char *__lookup_dev(char *path, dev_t dev, int dir_level, const int max_level)
40 /* Ignore strange nested directories */
41 if (dir_level > max_level)
44 path[PATH_MAX - 1] = '\0';
45 ptr = path + strlen(path);
48 space = PATH_MAX - (ptr - path);
54 while((entry = readdir(dir))) {
55 if (entry->d_name[0] == '.' ||
56 !strncmp(entry->d_name, "..", 2))
59 strncpy(ptr, entry->d_name, space);
60 if (stat(path, &st) < 0)
63 if (S_ISDIR(st.st_mode)) {
64 result = __lookup_dev(path, dev, dir_level + 1, max_level);
67 } else if (S_ISBLK(st.st_mode)) {
68 /* workaround: ignore dm-X devices, these are internal kernel names */
69 if (dir_level == 0 && dm_is_dm_kernel_name(entry->d_name))
71 if (st.st_rdev == dev) {
72 result = strdup(path);
83 * Non-udev systemd need to scan for device here.
85 static char *lookup_dev_old(int major, int minor)
88 char *result = NULL, buf[PATH_MAX + 1];
90 dev = makedev(major, minor);
91 strncpy(buf, "/dev", PATH_MAX);
94 /* First try low level device */
95 if ((result = __lookup_dev(buf, dev, 0, 0)))
98 /* If it is dm, try DM dir */
99 if (dm_is_dm_device(major, minor)) {
100 strncpy(buf, dm_get_dir(), PATH_MAX);
101 if ((result = __lookup_dev(buf, dev, 0, 0)))
105 strncpy(buf, "/dev", PATH_MAX);
106 return __lookup_dev(buf, dev, 0, 4);
110 * Returns string pointing to device in /dev according to "major:minor" dev_id
112 char *crypt_lookup_dev(const char *dev_id)
115 char link[PATH_MAX], path[PATH_MAX], *devname, *devpath = NULL;
119 if (sscanf(dev_id, "%d:%d", &major, &minor) != 2)
122 if (snprintf(path, sizeof(path), "/sys/dev/block/%s", dev_id) < 0)
125 len = readlink(path, link, sizeof(link));
127 /* Without /sys use old scan */
128 if (stat("/sys/dev/block", &st) < 0)
129 return lookup_dev_old(major, minor);
134 devname = strrchr(link, '/');
139 if (dm_is_dm_kernel_name(devname))
140 devpath = dm_device_path(major, minor);
141 else if (snprintf(path, sizeof(path), "/dev/%s", devname) > 0)
142 devpath = strdup(path);
145 * Check that path is correct.
147 if (devpath && ((stat(devpath, &st) < 0) ||
148 !S_ISBLK(st.st_mode) ||
149 (st.st_rdev != makedev(major, minor)))) {
151 /* Should never happen unless user mangles with dev nodes. */
152 return lookup_dev_old(major, minor);