]>
git.ipfire.org Git - thirdparty/systemd.git/blob - src/udev/udev-node.c
2 * Copyright (C) 2003-2013 Kay Sievers <kay@vrfy.org>
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
30 #include <sys/types.h>
33 #include "smack-util.h"
35 static int node_symlink(struct udev_device
*dev
, const char *node
, const char *slink
) {
37 char target
[UTIL_PATH_SIZE
];
40 char slink_tmp
[UTIL_PATH_SIZE
+ 32];
45 /* use relative link */
47 while (node
[i
] && (node
[i
] == slink
[i
])) {
54 while (slink
[i
] != '\0') {
56 l
= strpcpy(&s
, l
, "../");
59 l
= strscpy(s
, l
, &node
[tail
]);
65 /* preserve link with correct target, do not replace node of other device */
66 if (lstat(slink
, &stats
) == 0) {
67 if (S_ISBLK(stats
.st_mode
) || S_ISCHR(stats
.st_mode
)) {
68 log_error("conflicting device node '%s' found, link to '%s' will not be created", slink
, node
);
70 } else if (S_ISLNK(stats
.st_mode
)) {
71 char buf
[UTIL_PATH_SIZE
];
74 len
= readlink(slink
, buf
, sizeof(buf
));
75 if (len
> 0 && len
< (int)sizeof(buf
)) {
77 if (streq(target
, buf
)) {
78 log_debug("preserve already existing symlink '%s' to '%s'", slink
, target
);
79 label_fix(slink
, true, false);
80 utimensat(AT_FDCWD
, slink
, NULL
, AT_SYMLINK_NOFOLLOW
);
86 log_debug("creating symlink '%s' to '%s'", slink
, target
);
88 err
= mkdir_parents_label(slink
, 0755);
89 if (err
!= 0 && err
!= -ENOENT
)
91 mac_selinux_create_file_prepare(slink
, S_IFLNK
);
92 err
= symlink(target
, slink
);
95 mac_selinux_create_file_clear();
96 } while (err
== -ENOENT
);
101 log_debug("atomically replace '%s'", slink
);
102 strscpyl(slink_tmp
, sizeof(slink_tmp
), slink
, ".tmp-", udev_device_get_id_filename(dev
), NULL
);
105 err
= mkdir_parents_label(slink_tmp
, 0755);
106 if (err
!= 0 && err
!= -ENOENT
)
108 mac_selinux_create_file_prepare(slink_tmp
, S_IFLNK
);
109 err
= symlink(target
, slink_tmp
);
112 mac_selinux_create_file_clear();
113 } while (err
== -ENOENT
);
115 log_error("symlink '%s' '%s' failed: %m", target
, slink_tmp
);
118 err
= rename(slink_tmp
, slink
);
120 log_error("rename '%s' '%s' failed: %m", slink_tmp
, slink
);
127 /* find device node of device with highest priority */
128 static const char *link_find_prioritized(struct udev_device
*dev
, bool add
, const char *stackdir
, char *buf
, size_t bufsize
) {
129 struct udev
*udev
= udev_device_get_udev(dev
);
132 const char *target
= NULL
;
135 priority
= udev_device_get_devlink_priority(dev
);
136 strscpy(buf
, bufsize
, udev_device_get_devnode(dev
));
140 dir
= opendir(stackdir
);
144 struct udev_device
*dev_db
;
148 if (dent
== NULL
|| dent
->d_name
[0] == '\0')
150 if (dent
->d_name
[0] == '.')
153 log_debug("found '%s' claiming '%s'", dent
->d_name
, stackdir
);
155 /* did we find ourself? */
156 if (streq(dent
->d_name
, udev_device_get_id_filename(dev
)))
159 dev_db
= udev_device_new_from_device_id(udev
, dent
->d_name
);
160 if (dev_db
!= NULL
) {
163 devnode
= udev_device_get_devnode(dev_db
);
164 if (devnode
!= NULL
) {
165 if (target
== NULL
|| udev_device_get_devlink_priority(dev_db
) > priority
) {
166 log_debug("'%s' claims priority %i for '%s'",
167 udev_device_get_syspath(dev_db
), udev_device_get_devlink_priority(dev_db
), stackdir
);
168 priority
= udev_device_get_devlink_priority(dev_db
);
169 strscpy(buf
, bufsize
, devnode
);
173 udev_device_unref(dev_db
);
180 /* manage "stack of names" with possibly specified device priorities */
181 static void link_update(struct udev_device
*dev
, const char *slink
, bool add
) {
182 char name_enc
[UTIL_PATH_SIZE
];
183 char filename
[UTIL_PATH_SIZE
* 2];
184 char dirname
[UTIL_PATH_SIZE
];
186 char buf
[UTIL_PATH_SIZE
];
188 util_path_encode(slink
+ strlen("/dev"), name_enc
, sizeof(name_enc
));
189 strscpyl(dirname
, sizeof(dirname
), "/run/udev/links/", name_enc
, NULL
);
190 strscpyl(filename
, sizeof(filename
), dirname
, "/", udev_device_get_id_filename(dev
), NULL
);
192 if (!add
&& unlink(filename
) == 0)
195 target
= link_find_prioritized(dev
, add
, dirname
, buf
, sizeof(buf
));
196 if (target
== NULL
) {
197 log_debug("no reference left, remove '%s'", slink
);
198 if (unlink(slink
) == 0)
199 rmdir_parents(slink
, "/");
201 log_debug("creating link '%s' to '%s'", slink
, target
);
202 node_symlink(dev
, target
, slink
);
211 err
= mkdir_parents(filename
, 0755);
212 if (err
!= 0 && err
!= -ENOENT
)
214 fd
= open(filename
, O_WRONLY
|O_CREAT
|O_CLOEXEC
|O_TRUNC
|O_NOFOLLOW
, 0444);
219 } while (err
== -ENOENT
);
223 void udev_node_update_old_links(struct udev_device
*dev
, struct udev_device
*dev_old
) {
224 struct udev_list_entry
*list_entry
;
226 /* update possible left-over symlinks */
227 udev_list_entry_foreach(list_entry
, udev_device_get_devlinks_list_entry(dev_old
)) {
228 const char *name
= udev_list_entry_get_name(list_entry
);
229 struct udev_list_entry
*list_entry_current
;
232 /* check if old link name still belongs to this device */
234 udev_list_entry_foreach(list_entry_current
, udev_device_get_devlinks_list_entry(dev
)) {
235 const char *name_current
= udev_list_entry_get_name(list_entry_current
);
237 if (streq(name
, name_current
)) {
245 log_debug("update old name, '%s' no longer belonging to '%s'",
246 name
, udev_device_get_devpath(dev
));
247 link_update(dev
, name
, false);
251 static int node_permissions_apply(struct udev_device
*dev
, bool apply
,
252 mode_t mode
, uid_t uid
, gid_t gid
,
253 struct udev_list
*seclabel_list
) {
254 const char *devnode
= udev_device_get_devnode(dev
);
255 dev_t devnum
= udev_device_get_devnum(dev
);
257 struct udev_list_entry
*entry
;
260 if (streq(udev_device_get_subsystem(dev
), "block"))
265 if (lstat(devnode
, &stats
) != 0) {
267 log_debug("can not stat() node '%s' (%m)", devnode
);
271 if (((stats
.st_mode
& S_IFMT
) != (mode
& S_IFMT
)) || (stats
.st_rdev
!= devnum
)) {
273 log_debug("found node '%s' with non-matching devnum %s, skip handling",
274 udev_device_get_devnode(dev
), udev_device_get_id_filename(dev
));
279 bool selinux
= false;
282 if ((stats
.st_mode
& 0777) != (mode
& 0777) || stats
.st_uid
!= uid
|| stats
.st_gid
!= gid
) {
283 log_debug("set permissions %s, %#o, uid=%u, gid=%u", devnode
, mode
, uid
, gid
);
284 err
= chmod(devnode
, mode
);
286 log_warning("setting mode of %s to %#o failed: %m", devnode
, mode
);
287 err
= chown(devnode
, uid
, gid
);
289 log_warning("setting owner of %s to uid=%u, gid=%u failed: %m", devnode
, uid
, gid
);
291 log_debug("preserve permissions %s, %#o, uid=%u, gid=%u", devnode
, mode
, uid
, gid
);
294 /* apply SECLABEL{$module}=$label */
295 udev_list_entry_foreach(entry
, udev_list_get_entry(seclabel_list
)) {
296 const char *name
, *label
;
299 name
= udev_list_entry_get_name(entry
);
300 label
= udev_list_entry_get_value(entry
);
302 if (streq(name
, "selinux")) {
305 r
= mac_selinux_apply(devnode
, label
);
307 log_error("SECLABEL: failed to set SELinux label '%s': %s", label
, strerror(-r
));
309 log_debug("SECLABEL: set SELinux label '%s'", label
);
311 } else if (streq(name
, "smack")) {
314 r
= mac_smack_apply(devnode
, label
);
316 log_error("SECLABEL: failed to set SMACK label '%s': %s", label
, strerror(-r
));
318 log_debug("SECLABEL: set SMACK label '%s'", label
);
321 log_error("SECLABEL: unknown subsystem, ignoring '%s'='%s'", name
, label
);
324 /* set the defaults */
326 label_fix(devnode
, true, false);
328 mac_smack_apply(devnode
, NULL
);
331 /* always update timestamp when we re-use the node, like on media change events */
332 utimensat(AT_FDCWD
, devnode
, NULL
, 0);
337 void udev_node_add(struct udev_device
*dev
, bool apply
,
338 mode_t mode
, uid_t uid
, gid_t gid
,
339 struct udev_list
*seclabel_list
) {
340 char filename
[UTIL_PATH_SIZE
];
341 struct udev_list_entry
*list_entry
;
343 log_debug("handling device node '%s', devnum=%s, mode=%#o, uid=%d, gid=%d",
344 udev_device_get_devnode(dev
), udev_device_get_id_filename(dev
), mode
, uid
, gid
);
346 if (node_permissions_apply(dev
, apply
, mode
, uid
, gid
, seclabel_list
) < 0)
349 /* always add /dev/{block,char}/$major:$minor */
350 snprintf(filename
, sizeof(filename
), "/dev/%s/%u:%u",
351 streq(udev_device_get_subsystem(dev
), "block") ? "block" : "char",
352 major(udev_device_get_devnum(dev
)), minor(udev_device_get_devnum(dev
)));
353 node_symlink(dev
, udev_device_get_devnode(dev
), filename
);
355 /* create/update symlinks, add symlinks to name index */
356 udev_list_entry_foreach(list_entry
, udev_device_get_devlinks_list_entry(dev
))
357 link_update(dev
, udev_list_entry_get_name(list_entry
), true);
360 void udev_node_remove(struct udev_device
*dev
) {
361 struct udev_list_entry
*list_entry
;
362 char filename
[UTIL_PATH_SIZE
];
364 /* remove/update symlinks, remove symlinks from name index */
365 udev_list_entry_foreach(list_entry
, udev_device_get_devlinks_list_entry(dev
))
366 link_update(dev
, udev_list_entry_get_name(list_entry
), false);
368 /* remove /dev/{block,char}/$major:$minor */
369 snprintf(filename
, sizeof(filename
), "/dev/%s/%u:%u",
370 streq(udev_device_get_subsystem(dev
), "block") ? "block" : "char",
371 major(udev_device_get_devnum(dev
)), minor(udev_device_get_devnum(dev
)));