void udev_watch_begin(struct udev *udev, struct udev_device *dev)
{
char filename[UTIL_PATH_SIZE];
char majmin[UTIL_PATH_SIZE];
int wd;
if (inotify_fd < 0)
return;
info(udev, "adding watch on '%s'\n", udev_device_get_devnode(dev));
wd = inotify_add_watch(inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE);
if (wd < 0) {
err(udev, "inotify_add_watch(%d, %s, %o) failed: %m\n",
inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE);
return;
}
snprintf(majmin, sizeof(majmin), "%c%i:%i",
strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c',
major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);
util_create_path(udev, filename);
unlink(filename);
symlink(majmin, filename);
udev_device_set_watch_handle(dev, wd);
}
/* reverse mapping from the device file name to the devpath */
static int name_index(struct udev *udev, const char *devpath, const char *name, int add, int test)
{
char device[UTIL_PATH_SIZE];
char filename[UTIL_PATH_SIZE * 2];
size_t devlen = strlen(udev_get_dev_path(udev))+1;
size_t start;
int fd;
/* directory with device name */
util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
start = util_strlcat(filename, "/.udev/names/", sizeof(filename));
util_strlcat(filename, &name[devlen], sizeof(filename));
util_path_encode(&filename[start], sizeof(filename) - start);
/* entry with the devpath */
util_strlcpy(device, devpath, sizeof(device));
util_path_encode(device, sizeof(device));
util_strlcat(filename, "/", sizeof(filename));
util_strlcat(filename, device, sizeof(filename));
if (add) {
dbg(udev, "creating index: '%s'\n", filename);
util_create_path(udev, filename);
fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
if (fd > 0)
close(fd);
} else {
dbg(udev, "removing index: '%s'\n", filename);
unlink(filename);
util_delete_path(udev, filename);
}
return 0;
}
/* manage "stack of names" with possibly specified device priorities */
static void link_update(struct udev_device *dev, const char *slink, bool add)
{
struct udev *udev = udev_device_get_udev(dev);
char name_enc[UTIL_PATH_SIZE];
char filename[UTIL_PATH_SIZE * 2];
char dirname[UTIL_PATH_SIZE];
const char *target;
char buf[UTIL_PATH_SIZE];
dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
util_strscpyl(dirname, sizeof(dirname), udev_get_run_path(udev), "/links/", name_enc, NULL);
util_strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL);
if (!add) {
dbg(udev, "removing index: '%s'\n", filename);
if (unlink(filename) == 0)
rmdir(dirname);
}
target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
if (target == NULL) {
info(udev, "no reference left, remove '%s'\n", slink);
if (unlink(slink) == 0)
util_delete_path(udev, slink);
} else {
info(udev, "creating link '%s' to '%s'\n", slink, target);
node_symlink(udev, target, slink);
}
if (add) {
int err;
dbg(udev, "creating index: '%s'\n", filename);
do {
int fd;
err = util_create_path(udev, filename);
if (err != 0 && err != -ENOENT)
break;
fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
if (fd >= 0)
close(fd);
else
err = -errno;
} while (err == -ENOENT);
}
}
int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid, int test)
{
struct udev *udev = udev_device_get_udev(dev);
int i;
int num;
struct udev_list_entry *list_entry;
int err = 0;
info(udev, "creating device node '%s', devnum=%d:%d, mode=%#o, uid=%d, gid=%d\n",
udev_device_get_devnode(dev),
major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)),
mode, uid, gid);
util_create_path(udev, udev_device_get_devnode(dev));
if (!test)
if (udev_node_mknod(dev, NULL, makedev(0,0), mode, uid, gid) != 0) {
err = -1;
goto exit;
}
/* create all_partitions if requested */
num = udev_device_get_num_fake_partitions(dev);
if (num > 0) {
info(udev, "creating device partition nodes '%s[1-%i]'\n", udev_device_get_devnode(dev), num);
if (!test) {
for (i = 1; i <= num; i++) {
char partitionname[UTIL_PATH_SIZE];
dev_t part_devnum;
snprintf(partitionname, sizeof(partitionname), "%s%d",
udev_device_get_devnode(dev), i);
partitionname[sizeof(partitionname)-1] = '\0';
part_devnum = makedev(major(udev_device_get_devnum(dev)),
minor(udev_device_get_devnum(dev)) + i);
udev_node_mknod(dev, partitionname, part_devnum, mode, uid, gid);
}
}
}
/* add node to name index */
name_index(udev, udev_device_get_devpath(dev), udev_device_get_devnode(dev), 1, test);
/* create/update symlinks, add symlinks to name index */
udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
name_index(udev, udev_device_get_devpath(dev), udev_list_entry_get_name(list_entry), 1, test);
update_link(dev, udev_list_entry_get_name(list_entry), test);
}
/* manage "stack of names" with possibly specified device priorities */
static void link_update(struct udev_device *dev, const char *slink, bool add)
{
struct udev *udev = udev_device_get_udev(dev);
char name_enc[UTIL_PATH_SIZE];
char filename[UTIL_PATH_SIZE * 2];
char dirname[UTIL_PATH_SIZE];
const char *target;
char buf[UTIL_PATH_SIZE];
dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
snprintf(dirname, sizeof(dirname), "%s/.udev/links/%s", udev_get_dev_path(udev), name_enc);
snprintf(filename, sizeof(filename), "%s/%c%u:%u", dirname,
strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c',
major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
if (!add) {
dbg(udev, "removing index: '%s'\n", filename);
unlink(filename);
util_delete_path(udev, filename);
}
target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
if (target == NULL) {
info(udev, "no reference left, remove '%s'\n", slink);
unlink(slink);
util_delete_path(udev, slink);
} else {
info(udev, "creating link '%s' to '%s'\n", slink, target);
node_symlink(udev, target, slink);
}
if (add) {
int err;
dbg(udev, "creating index: '%s'\n", filename);
do {
err = util_create_path(udev, filename);
if (err != 0 && err != -ENOENT)
break;
err = symlink(udev_device_get_devpath(dev), filename);
if (err != 0)
err = -errno;
} while (err == -ENOENT);
}
}
static int create_path(struct udev *udev, const char *path, bool selinux)
{
char p[UTIL_PATH_SIZE];
char *pos;
struct stat stats;
int err;
util_strscpy(p, sizeof(p), path);
pos = strrchr(p, '/');
if (pos == NULL)
return 0;
while (pos != p && pos[-1] == '/')
pos--;
if (pos == p)
return 0;
pos[0] = '\0';
dbg(udev, "stat '%s'\n", p);
if (stat(p, &stats) == 0) {
if ((stats.st_mode & S_IFMT) == S_IFDIR)
return 0;
else
return -ENOTDIR;
}
err = util_create_path(udev, p);
if (err != 0)
return err;
dbg(udev, "mkdir '%s'\n", p);
if (selinux)
udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
err = mkdir(p, 0755);
if (err != 0) {
err = -errno;
if (err == -EEXIST && stat(p, &stats) == 0) {
if ((stats.st_mode & S_IFMT) == S_IFDIR)
err = 0;
else
err = -ENOTDIR;
}
}
if (selinux)
udev_selinux_resetfscreatecon(udev);
return err;
}
void udev_watch_begin(struct udev *udev, struct udev_device *dev)
{
char filename[UTIL_PATH_SIZE];
int wd;
if (inotify_fd < 0)
return;
info(udev, "adding watch on '%s'\n", udev_device_get_devnode(dev));
wd = inotify_add_watch(inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE);
if (wd < 0) {
err(udev, "inotify_add_watch(%d, %s, %o) failed: %m\n",
inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE);
}
snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);
util_create_path(udev, filename);
unlink(filename);
symlink(udev_device_get_devpath(dev), filename);
udev_device_set_watch_handle(dev, wd);
}
int main(int argc, char *argv[])
{
struct udev *udev;
struct udev_event *event = NULL;
struct udev_device *dev = NULL;
struct udev_rules *rules = NULL;
char syspath[UTIL_PATH_SIZE];
const char *devpath;
const char *action;
sigset_t mask, sigmask_orig;
int err = -EINVAL;
udev = udev_new();
if (udev == NULL)
exit(1);
info(udev, "version %s\n", VERSION);
udev_selinux_init(udev);
sigprocmask(SIG_SETMASK, NULL, &sigmask_orig);
action = argv[1];
if (action == NULL) {
err(udev, "action missing\n");
goto out;
}
devpath = argv[2];
if (devpath == NULL) {
err(udev, "devpath missing\n");
goto out;
}
rules = udev_rules_new(udev, 1);
util_strscpyl(syspath, sizeof(syspath), udev_get_sys_path(udev), devpath, NULL);
dev = udev_device_new_from_syspath(udev, syspath);
if (dev == NULL) {
info(udev, "unknown device '%s'\n", devpath);
goto out;
}
udev_device_set_action(dev, action);
event = udev_event_new(dev);
sigfillset(&mask);
sigprocmask(SIG_SETMASK, &mask, &sigmask_orig);
event->fd_signal = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
if (event->fd_signal < 0) {
fprintf(stderr, "error creating signalfd\n");
goto out;
}
/* do what devtmpfs usually provides us */
if (udev_device_get_devnode(dev) != NULL) {
mode_t mode;
if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
mode |= S_IFBLK;
else
mode |= S_IFCHR;
if (strcmp(action, "remove") != 0) {
util_create_path(udev, udev_device_get_devnode(dev));
mknod(udev_device_get_devnode(dev), mode, udev_device_get_devnum(dev));
} else {
unlink(udev_device_get_devnode(dev));
util_delete_path(udev, udev_device_get_devnode(dev));
}
}
err = udev_event_execute_rules(event, rules, &sigmask_orig);
if (err == 0)
udev_event_execute_run(event, NULL);
out:
if (event != NULL && event->fd_signal >= 0)
close(event->fd_signal);
udev_event_unref(event);
udev_device_unref(dev);
udev_rules_unref(rules);
udev_selinux_exit(udev);
udev_unref(udev);
if (err != 0)
return 1;
return 0;
}
static int update_link(struct udev_device *dev, const char *slink, int test)
{
struct udev *udev = udev_device_get_udev(dev);
struct udev_list_node dev_list;
struct udev_list_entry *dev_entry;
char target[UTIL_PATH_SIZE];
int count;
int priority = 0;
int rc = 0;
dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
udev_list_init(&dev_list);
count = name_index_get_devices(udev, slink, &dev_list);
if (count > 1)
info(udev, "found %i devices with name '%s'\n", count, slink);
/* if we don't have a reference, delete it */
if (count <= 0) {
info(udev, "no reference left, remove '%s'\n", slink);
if (!test) {
unlink(slink);
util_delete_path(udev, slink);
}
goto out;
}
/* find the device with the highest priority */
target[0] = '\0';
udev_list_entry_foreach(dev_entry, udev_list_get_entry(&dev_list)) {
const char *syspath;
struct udev_device *dev_db;
const char *devnode;
syspath = udev_list_entry_get_name(dev_entry);
dbg(udev, "found '%s' for '%s'\n", syspath, slink);
/* did we find ourself? we win, if we have the same priority */
if (strcmp(udev_device_get_syspath(dev), syspath) == 0) {
dbg(udev, "compare (our own) priority of '%s' %i >= %i\n",
udev_device_get_devpath(dev), udev_device_get_devlink_priority(dev), priority);
if (strcmp(udev_device_get_devnode(dev), slink) == 0) {
info(udev, "'%s' is our device node, database inconsistent, skip link update\n",
udev_device_get_devnode(dev));
} else if (target[0] == '\0' || udev_device_get_devlink_priority(dev) >= priority) {
priority = udev_device_get_devlink_priority(dev);
util_strlcpy(target, udev_device_get_devnode(dev), sizeof(target));
}
continue;
}
/* another device, read priority from database */
dev_db = udev_device_new_from_syspath(udev, syspath);
if (dev_db == NULL)
continue;
devnode = udev_device_get_devnode(dev_db);
if (devnode != NULL) {
if (strcmp(devnode, slink) == 0) {
info(udev, "'%s' is a device node of '%s', skip link update\n",
devnode, syspath);
} else {
dbg(udev, "compare priority of '%s' %i > %i\n",
udev_device_get_devpath(dev_db),
udev_device_get_devlink_priority(dev_db),
priority);
if (target[0] == '\0' || udev_device_get_devlink_priority(dev_db) > priority) {
priority = udev_device_get_devlink_priority(dev_db);
util_strlcpy(target, devnode, sizeof(target));
}
}
}
udev_device_unref(dev_db);
}
udev_list_cleanup_entries(udev, &dev_list);
if (target[0] == '\0') {
info(udev, "no current target for '%s' found\n", slink);
rc = 1;
goto out;
}
/* create symlink to the target with the highest priority */
info(udev, "'%s' with target '%s' has the highest priority %i, create it\n", slink, target, priority);
if (!test) {
util_create_path(udev, slink);
node_symlink(udev, target, slink);
}
out:
return rc;
}
int udev_node_mknod(struct udev_device *dev, const char *file, mode_t mode, uid_t uid, gid_t gid)
{
struct udev *udev = udev_device_get_udev(dev);
dev_t devnum = udev_device_get_devnum(dev);
struct stat stats;
int err = 0;
if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
mode |= S_IFBLK;
else
mode |= S_IFCHR;
if (file == NULL)
file = udev_device_get_devnode(dev);
if (lstat(file, &stats) == 0) {
if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devnum)) {
info(udev, "preserve file '%s', because it has correct dev_t\n", file);
if (stats.st_mode != mode || stats.st_uid != uid || stats.st_gid != gid) {
info(udev, "set permissions %s, %#o, uid=%u, gid=%u\n", file, mode, uid, gid);
chmod(file, mode);
chown(file, uid, gid);
} else {
info(udev, "preserve permissions %s, %#o, uid=%u, gid=%u\n", file, mode, uid, gid);
}
/*
* Set initial selinux file context only on add events.
* We set the proper context on bootup (triger) or for newly
* added devices, but we don't change it later, in case
* something else has set a custom context in the meantime.
*/
if (strcmp(udev_device_get_action(dev), "add") == 0)
udev_selinux_lsetfilecon(udev, file, mode);
/* always update timestamp when we re-use the node, like on media change events */
utimensat(AT_FDCWD, file, NULL, 0);
} else {
char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
info(udev, "atomically replace existing file '%s'\n", file);
util_strscpyl(file_tmp, sizeof(file_tmp), file, TMP_FILE_EXT, NULL);
unlink(file_tmp);
udev_selinux_setfscreatecon(udev, file_tmp, mode);
err = mknod(file_tmp, mode, devnum);
udev_selinux_resetfscreatecon(udev);
if (err != 0) {
err(udev, "mknod '%s' %u:%u %#o failed: %m\n",
file_tmp, major(devnum), minor(devnum), mode);
goto exit;
}
err = rename(file_tmp, file);
if (err != 0) {
err(udev, "rename '%s' '%s' failed: %m\n", file_tmp, file);
unlink(file_tmp);
goto exit;
}
info(udev, "set permissions '%s' %#o uid=%u gid=%u\n", file, mode, uid, gid);
chmod(file, mode);
chown(file, uid, gid);
}
} else {
info(udev, "mknod '%s' %u:%u %#o\n", file, major(devnum), minor(devnum), mode);
do {
err = util_create_path(udev, file);
if (err != 0 && err != -ENOENT)
break;
udev_selinux_setfscreatecon(udev, file, mode);
err = mknod(file, mode, devnum);
if (err != 0)
err = -errno;
udev_selinux_resetfscreatecon(udev);
} while (err == -ENOENT);
if (err != 0)
err(udev, "mknod '%s' %u:%u %#o' failed: %m\n", file, major(devnum), minor(devnum), mode);
info(udev, "set permissions '%s' %#o uid=%u gid=%u\n", file, mode, uid, gid);
chmod(file, mode);
chown(file, uid, gid);
}
exit:
return err;
}
static int node_symlink(struct udev *udev, const char *node, const char *slink)
{
struct stat stats;
char target[UTIL_PATH_SIZE];
char *s;
size_t l;
char slink_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
int i = 0;
int tail = 0;
int err = 0;
/* use relative link */
target[0] = '\0';
while (node[i] && (node[i] == slink[i])) {
if (node[i] == '/')
tail = i+1;
i++;
}
s = target;
l = sizeof(target);
while (slink[i] != '\0') {
if (slink[i] == '/')
l = util_strpcpy(&s, l, "../");
i++;
}
l = util_strscpy(s, l, &node[tail]);
if (l == 0) {
err = -EINVAL;
goto exit;
}
/* preserve link with correct target, do not replace node of other device */
if (lstat(slink, &stats) == 0) {
if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
struct stat stats2;
info(udev, "found existing node instead of symlink '%s'\n", slink);
if (lstat(node, &stats2) == 0) {
if ((stats.st_mode & S_IFMT) == (stats2.st_mode & S_IFMT) &&
stats.st_rdev == stats2.st_rdev && stats.st_ino != stats2.st_ino) {
info(udev, "replace device node '%s' with symlink to our node '%s'\n",
slink, node);
} else {
err(udev, "device node '%s' already exists, "
"link to '%s' will not overwrite it\n",
slink, node);
goto exit;
}
}
} else if (S_ISLNK(stats.st_mode)) {
char buf[UTIL_PATH_SIZE];
int len;
dbg(udev, "found existing symlink '%s'\n", slink);
len = readlink(slink, buf, sizeof(buf));
if (len > 0 && len < (int)sizeof(buf)) {
buf[len] = '\0';
if (strcmp(target, buf) == 0) {
info(udev, "preserve already existing symlink '%s' to '%s'\n",
slink, target);
udev_selinux_lsetfilecon(udev, slink, S_IFLNK);
utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
goto exit;
}
}
}
} else {
info(udev, "creating symlink '%s' to '%s'\n", slink, target);
do {
err = util_create_path(udev, slink);
if (err != 0 && err != -ENOENT)
break;
udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
err = symlink(target, slink);
if (err != 0)
err = -errno;
udev_selinux_resetfscreatecon(udev);
} while (err == -ENOENT);
if (err == 0)
goto exit;
}
info(udev, "atomically replace '%s'\n", slink);
util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
unlink(slink_tmp);
do {
err = util_create_path(udev, slink_tmp);
if (err != 0 && err != -ENOENT)
break;
udev_selinux_setfscreatecon(udev, slink_tmp, S_IFLNK);
err = symlink(target, slink_tmp);
if (err != 0)
err = -errno;
udev_selinux_resetfscreatecon(udev);
} while (err == -ENOENT);
if (err != 0) {
err(udev, "symlink '%s' '%s' failed: %m\n", target, slink_tmp);
goto exit;
}
err = rename(slink_tmp, slink);
if (err != 0) {
err(udev, "rename '%s' '%s' failed: %m\n", slink_tmp, slink);
unlink(slink_tmp);
}
exit:
return err;
}
int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mode_t mode, uid_t uid, gid_t gid)
{
struct udev *udev = udev_device_get_udev(dev);
struct stat stats;
int preserve = 0;
int err = 0;
if (major(devnum) == 0)
devnum = udev_device_get_devnum(dev);
if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
mode |= S_IFBLK;
else
mode |= S_IFCHR;
if (file == NULL)
file = udev_device_get_devnode(dev);
if (lstat(file, &stats) == 0) {
if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devnum)) {
info(udev, "preserve file '%s', because it has correct dev_t\n", file);
preserve = 1;
udev_selinux_lsetfilecon(udev, file, mode);
/* update time stamp when we re-use the node, like on media change events */
utimes(file, NULL);
} else {
char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
info(udev, "atomically replace existing file '%s'\n", file);
util_strscpyl(file_tmp, sizeof(file_tmp), file, TMP_FILE_EXT, NULL);
unlink(file_tmp);
udev_selinux_setfscreatecon(udev, file_tmp, mode);
err = mknod(file_tmp, mode, devnum);
udev_selinux_resetfscreatecon(udev);
if (err != 0) {
err(udev, "mknod(%s, %#o, %u, %u) failed: %m\n",
file_tmp, mode, major(devnum), minor(devnum));
goto exit;
}
err = rename(file_tmp, file);
if (err != 0) {
err(udev, "rename(%s, %s) failed: %m\n", file_tmp, file);
unlink(file_tmp);
}
}
} else {
info(udev, "mknod(%s, %#o, (%u,%u))\n", file, mode, major(devnum), minor(devnum));
do {
err = util_create_path(udev, file);
if (err != 0 && err != -ENOENT)
break;
udev_selinux_setfscreatecon(udev, file, mode);
err = mknod(file, mode, devnum);
if (err != 0)
err = -errno;
udev_selinux_resetfscreatecon(udev);
} while (err == -ENOENT);
if (err != 0) {
err(udev, "mknod(%s, %#o, (%u,%u) failed: %m\n", file, mode, major(devnum), minor(devnum));
goto exit;
}
}
if (!preserve || stats.st_mode != mode) {
info(udev, "chmod(%s, %#o)\n", file, mode);
err = chmod(file, mode);
if (err != 0) {
err(udev, "chmod(%s, %#o) failed: %m\n", file, mode);
goto exit;
}
}
if (!preserve || stats.st_uid != uid || stats.st_gid != gid) {
info(udev, "chown(%s, %u, %u)\n", file, uid, gid);
err = chown(file, uid, gid);
if (err != 0) {
err(udev, "chown(%s, %u, %u) failed: %m\n", file, uid, gid);
goto exit;
}
}
exit:
return err;
}
