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 char *crypt_lookup_dev(const char *dev_id);
33 static char *__lookup_dev(char *path, dev_t dev, int dir_level, const int max_level)
42 /* Ignore strange nested directories */
43 if (dir_level > max_level)
46 path[PATH_MAX - 1] = '\0';
47 ptr = path + strlen(path);
50 space = PATH_MAX - (ptr - path);
56 while((entry = readdir(dir))) {
57 if (entry->d_name[0] == '.' ||
58 !strncmp(entry->d_name, "..", 2))
62 (!strcmp(entry->d_name, "shm") ||
63 !strcmp(entry->d_name, "fd") ||
64 !strcmp(entry->d_name, "char") ||
65 !strcmp(entry->d_name, "pts")))
68 strncpy(ptr, entry->d_name, space);
69 if (stat(path, &st) < 0)
72 if (S_ISDIR(st.st_mode)) {
73 result = __lookup_dev(path, dev, dir_level + 1, max_level);
76 } else if (S_ISBLK(st.st_mode)) {
77 /* workaround: ignore dm-X devices, these are internal kernel names */
78 if (dir_level == 0 && dm_is_dm_kernel_name(entry->d_name))
80 if (st.st_rdev == dev) {
81 result = strdup(path);
92 * Non-udev systemd need to scan for device here.
94 static char *lookup_dev_old(int major, int minor)
97 char *result = NULL, buf[PATH_MAX + 1];
99 dev = makedev(major, minor);
100 strncpy(buf, "/dev", PATH_MAX);
101 buf[PATH_MAX] = '\0';
103 /* First try low level device */
104 if ((result = __lookup_dev(buf, dev, 0, 0)))
107 /* If it is dm, try DM dir */
108 if (dm_is_dm_device(major, minor)) {
109 strncpy(buf, dm_get_dir(), PATH_MAX);
110 if ((result = __lookup_dev(buf, dev, 0, 0)))
114 strncpy(buf, "/dev", PATH_MAX);
115 return __lookup_dev(buf, dev, 0, 4);
119 * Returns string pointing to device in /dev according to "major:minor" dev_id
121 char *crypt_lookup_dev(const char *dev_id)
124 char link[PATH_MAX], path[PATH_MAX], *devname, *devpath = NULL;
128 if (sscanf(dev_id, "%d:%d", &major, &minor) != 2)
131 if (snprintf(path, sizeof(path), "/sys/dev/block/%s", dev_id) < 0)
134 len = readlink(path, link, sizeof(link));
136 /* Without /sys use old scan */
137 if (stat("/sys/dev/block", &st) < 0)
138 return lookup_dev_old(major, minor);
143 devname = strrchr(link, '/');
148 if (dm_is_dm_kernel_name(devname))
149 devpath = dm_device_path(major, minor);
150 else if (snprintf(path, sizeof(path), "/dev/%s", devname) > 0)
151 devpath = strdup(path);
154 * Check that path is correct.
156 if (devpath && ((stat(devpath, &st) < 0) ||
157 !S_ISBLK(st.st_mode) ||
158 (st.st_rdev != makedev(major, minor)))) {
160 /* Should never happen unless user mangles with dev nodes. */
161 return lookup_dev_old(major, minor);