]>
git.ipfire.org Git - thirdparty/systemd.git/blob - src/udev-node.c
2 * Copyright (C) 2003-2010 Kay Sievers <kay.sievers@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>
34 #define TMP_FILE_EXT ".udev-tmp"
36 static int node_symlink(struct udev
*udev
, const char *node
, const char *slink
)
39 char target
[UTIL_PATH_SIZE
];
42 char slink_tmp
[UTIL_PATH_SIZE
+ sizeof(TMP_FILE_EXT
)];
47 /* use relative link */
49 while (node
[i
] && (node
[i
] == slink
[i
])) {
56 while (slink
[i
] != '\0') {
58 l
= util_strpcpy(&s
, l
, "../");
61 l
= util_strscpy(s
, l
, &node
[tail
]);
67 /* preserve link with correct target, do not replace node of other device */
68 if (lstat(slink
, &stats
) == 0) {
69 if (S_ISBLK(stats
.st_mode
) || S_ISCHR(stats
.st_mode
)) {
72 info(udev
, "found existing node instead of symlink '%s'\n", slink
);
73 if (lstat(node
, &stats2
) == 0) {
74 if ((stats
.st_mode
& S_IFMT
) == (stats2
.st_mode
& S_IFMT
) &&
75 stats
.st_rdev
== stats2
.st_rdev
&& stats
.st_ino
!= stats2
.st_ino
) {
76 info(udev
, "replace device node '%s' with symlink to our node '%s'\n",
79 err(udev
, "device node '%s' already exists, "
80 "link to '%s' will not overwrite it\n",
85 } else if (S_ISLNK(stats
.st_mode
)) {
86 char buf
[UTIL_PATH_SIZE
];
89 dbg(udev
, "found existing symlink '%s'\n", slink
);
90 len
= readlink(slink
, buf
, sizeof(buf
));
91 if (len
> 0 && len
< (int)sizeof(buf
)) {
93 if (strcmp(target
, buf
) == 0) {
94 info(udev
, "preserve already existing symlink '%s' to '%s'\n",
96 udev_selinux_lsetfilecon(udev
, slink
, S_IFLNK
);
97 utimensat(AT_FDCWD
, slink
, NULL
, AT_SYMLINK_NOFOLLOW
);
103 info(udev
, "creating symlink '%s' to '%s'\n", slink
, target
);
105 err
= util_create_path_selinux(udev
, slink
);
106 if (err
!= 0 && err
!= -ENOENT
)
108 udev_selinux_setfscreatecon(udev
, slink
, S_IFLNK
);
109 err
= symlink(target
, slink
);
112 udev_selinux_resetfscreatecon(udev
);
113 } while (err
== -ENOENT
);
118 info(udev
, "atomically replace '%s'\n", slink
);
119 util_strscpyl(slink_tmp
, sizeof(slink_tmp
), slink
, TMP_FILE_EXT
, NULL
);
122 err
= util_create_path_selinux(udev
, slink_tmp
);
123 if (err
!= 0 && err
!= -ENOENT
)
125 udev_selinux_setfscreatecon(udev
, slink_tmp
, S_IFLNK
);
126 err
= symlink(target
, slink_tmp
);
129 udev_selinux_resetfscreatecon(udev
);
130 } while (err
== -ENOENT
);
132 err(udev
, "symlink '%s' '%s' failed: %m\n", target
, slink_tmp
);
135 err
= rename(slink_tmp
, slink
);
137 err(udev
, "rename '%s' '%s' failed: %m\n", slink_tmp
, slink
);
144 /* find device node of device with highest priority */
145 static const char *link_find_prioritized(struct udev_device
*dev
, bool add
, const char *stackdir
, char *buf
, size_t bufsize
)
147 struct udev
*udev
= udev_device_get_udev(dev
);
150 const char *target
= NULL
;
153 priority
= udev_device_get_devlink_priority(dev
);
154 util_strscpy(buf
, bufsize
, udev_device_get_devnode(dev
));
158 dir
= opendir(stackdir
);
162 struct udev_device
*dev_db
;
166 if (dent
== NULL
|| dent
->d_name
[0] == '\0')
168 if (dent
->d_name
[0] == '.')
171 info(udev
, "found '%s' claiming '%s'\n", dent
->d_name
, stackdir
);
173 /* did we find ourself? */
174 if (strcmp(dent
->d_name
, udev_device_get_id_filename(dev
)) == 0)
177 dev_db
= udev_device_new_from_id_filename(udev
, dent
->d_name
);
178 if (dev_db
!= NULL
) {
181 devnode
= udev_device_get_devnode(dev_db
);
182 if (devnode
!= NULL
) {
183 dbg(udev
, "compare priority of '%s'(%i) > '%s'(%i)\n", target
, priority
,
184 udev_device_get_devnode(dev_db
), udev_device_get_devlink_priority(dev_db
));
185 if (target
== NULL
|| udev_device_get_devlink_priority(dev_db
) > priority
) {
186 info(udev
, "'%s' claims priority %i for '%s'\n",
187 udev_device_get_syspath(dev_db
), udev_device_get_devlink_priority(dev_db
), stackdir
);
188 priority
= udev_device_get_devlink_priority(dev_db
);
189 util_strscpy(buf
, bufsize
, devnode
);
193 udev_device_unref(dev_db
);
200 /* manage "stack of names" with possibly specified device priorities */
201 static void link_update(struct udev_device
*dev
, const char *slink
, bool add
)
203 struct udev
*udev
= udev_device_get_udev(dev
);
204 char name_enc
[UTIL_PATH_SIZE
];
205 char filename
[UTIL_PATH_SIZE
* 2];
206 char dirname
[UTIL_PATH_SIZE
];
208 char buf
[UTIL_PATH_SIZE
];
210 dbg(udev
, "update symlink '%s' of '%s'\n", slink
, udev_device_get_syspath(dev
));
212 util_path_encode(&slink
[strlen(udev_get_dev_path(udev
))+1], name_enc
, sizeof(name_enc
));
213 util_strscpyl(dirname
, sizeof(dirname
), udev_get_run_path(udev
), "/links/", name_enc
, NULL
);
214 util_strscpyl(filename
, sizeof(filename
), dirname
, "/", udev_device_get_id_filename(dev
), NULL
);
217 dbg(udev
, "removing index: '%s'\n", filename
);
218 if (unlink(filename
) == 0)
222 target
= link_find_prioritized(dev
, add
, dirname
, buf
, sizeof(buf
));
223 if (target
== NULL
) {
224 info(udev
, "no reference left, remove '%s'\n", slink
);
225 if (unlink(slink
) == 0)
226 util_delete_path(udev
, slink
);
228 info(udev
, "creating link '%s' to '%s'\n", slink
, target
);
229 node_symlink(udev
, target
, slink
);
235 dbg(udev
, "creating index: '%s'\n", filename
);
239 err
= util_create_path(udev
, filename
);
240 if (err
!= 0 && err
!= -ENOENT
)
242 fd
= open(filename
, O_WRONLY
|O_CREAT
|O_CLOEXEC
|O_TRUNC
|O_NOFOLLOW
, 0444);
247 } while (err
== -ENOENT
);
251 void udev_node_update_old_links(struct udev_device
*dev
, struct udev_device
*dev_old
)
253 struct udev
*udev
= udev_device_get_udev(dev
);
254 struct udev_list_entry
*list_entry
;
256 /* update possible left-over symlinks */
257 udev_list_entry_foreach(list_entry
, udev_device_get_devlinks_list_entry(dev_old
)) {
258 const char *name
= udev_list_entry_get_name(list_entry
);
259 struct udev_list_entry
*list_entry_current
;
262 /* check if old link name still belongs to this device */
264 udev_list_entry_foreach(list_entry_current
, udev_device_get_devlinks_list_entry(dev
)) {
265 const char *name_current
= udev_list_entry_get_name(list_entry_current
);
267 if (strcmp(name
, name_current
) == 0) {
275 info(udev
, "update old name, '%s' no longer belonging to '%s'\n",
276 name
, udev_device_get_devpath(dev
));
277 link_update(dev
, name
, 0);
281 static int node_fixup(struct udev_device
*dev
, mode_t mode
, uid_t uid
, gid_t gid
)
283 struct udev
*udev
= udev_device_get_udev(dev
);
284 const char *devnode
= udev_device_get_devnode(dev
);
285 dev_t devnum
= udev_device_get_devnum(dev
);
289 if (strcmp(udev_device_get_subsystem(dev
), "block") == 0)
294 if (lstat(devnode
, &stats
) != 0) {
296 info(udev
, "can not stat() node '%s' (%m)\n", devnode
);
300 if (((stats
.st_mode
& S_IFMT
) != (mode
& S_IFMT
)) || (stats
.st_rdev
!= devnum
)) {
302 info(udev
, "found node '%s' with non-matching devnum %s, skip handling\n",
303 udev_device_get_devnode(dev
), udev_device_get_id_filename(dev
));
307 if ((stats
.st_mode
& 0777) != (mode
& 0777) || stats
.st_uid
!= uid
|| stats
.st_gid
!= gid
) {
308 info(udev
, "set permissions %s, %#o, uid=%u, gid=%u\n", devnode
, mode
, uid
, gid
);
309 chmod(devnode
, mode
);
310 chown(devnode
, uid
, gid
);
312 info(udev
, "preserve permissions %s, %#o, uid=%u, gid=%u\n", devnode
, mode
, uid
, gid
);
316 * Set initial selinux file context only on add events.
317 * We set the proper context on bootup (triger) or for newly
318 * added devices, but we don't change it later, in case
319 * something else has set a custom context in the meantime.
321 if (strcmp(udev_device_get_action(dev
), "add") == 0)
322 udev_selinux_lsetfilecon(udev
, devnode
, mode
);
324 /* always update timestamp when we re-use the node, like on media change events */
325 utimensat(AT_FDCWD
, devnode
, NULL
, 0);
330 void udev_node_add(struct udev_device
*dev
, mode_t mode
, uid_t uid
, gid_t gid
)
332 struct udev
*udev
= udev_device_get_udev(dev
);
333 char filename
[UTIL_PATH_SIZE
];
334 struct udev_list_entry
*list_entry
;
337 info(udev
, "handling device node '%s', devnum=%s, mode=%#o, uid=%d, gid=%d\n",
338 udev_device_get_devnode(dev
), udev_device_get_id_filename(dev
), mode
, uid
, gid
);
340 if (node_fixup(dev
, mode
, uid
, gid
) < 0)
343 /* always add /dev/{block,char}/$major:$minor */
344 snprintf(filename
, sizeof(filename
), "%s/%s/%u:%u",
345 udev_get_dev_path(udev
),
346 strcmp(udev_device_get_subsystem(dev
), "block") == 0 ? "block" : "char",
347 major(udev_device_get_devnum(dev
)), minor(udev_device_get_devnum(dev
)));
348 node_symlink(udev
, udev_device_get_devnode(dev
), filename
);
350 /* create/update symlinks, add symlinks to name index */
351 udev_list_entry_foreach(list_entry
, udev_device_get_devlinks_list_entry(dev
)) {
352 if (udev_list_entry_get_num(list_entry
))
353 /* simple unmanaged link name */
354 node_symlink(udev
, udev_device_get_devnode(dev
), udev_list_entry_get_name(list_entry
));
356 link_update(dev
, udev_list_entry_get_name(list_entry
), 1);
360 void udev_node_remove(struct udev_device
*dev
)
362 struct udev
*udev
= udev_device_get_udev(dev
);
363 struct udev_list_entry
*list_entry
;
366 struct udev_device
*dev_check
;
367 char filename
[UTIL_PATH_SIZE
];
369 /* remove/update symlinks, remove symlinks from name index */
370 udev_list_entry_foreach(list_entry
, udev_device_get_devlinks_list_entry(dev
))
371 link_update(dev
, udev_list_entry_get_name(list_entry
), 0);
373 /* remove /dev/{block,char}/$major:$minor */
374 snprintf(filename
, sizeof(filename
), "%s/%s/%u:%u",
375 udev_get_dev_path(udev
),
376 strcmp(udev_device_get_subsystem(dev
), "block") == 0 ? "block" : "char",
377 major(udev_device_get_devnum(dev
)), minor(udev_device_get_devnum(dev
)));