struct udev_device *udev_watch_lookup(struct udev *udev, int wd)
{
char filename[UTIL_PATH_SIZE];
char majmin[UTIL_PATH_SIZE];
char *s;
size_t l;
ssize_t len;
int maj, min;
char type;
dev_t devnum;
if (inotify_fd < 0 || wd < 0)
return NULL;
snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);
s = majmin;
l = util_strpcpy(&s, sizeof(majmin), udev_get_sys_path(udev));
len = readlink(filename, s, l);
if (len <= 0 || (size_t)len == l)
return NULL;
s[len] = '\0';
if (sscanf(s, "%c%i:%i", &type, &maj, &min) != 3)
return NULL;
devnum = makedev(maj, min);
return udev_device_new_from_devnum(udev, type, devnum);
}
/* move any old watches directory out of the way, and then restore
* the watches
*/
void udev_watch_restore(struct udev *udev)
{
char filename[UTIL_PATH_SIZE], oldname[UTIL_PATH_SIZE];
if (inotify_fd < 0)
return;
util_strscpyl(oldname, sizeof(oldname), udev_get_dev_path(udev), "/.udev/watch.old", NULL);
util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/watch", NULL);
if (rename(filename, oldname) == 0) {
DIR *dir;
struct dirent *ent;
dir = opendir(oldname);
if (dir == NULL) {
err(udev, "unable to open old watches dir '%s', old watches will not be restored: %m", oldname);
return;
}
for (ent = readdir(dir); ent != NULL; ent = readdir(dir)) {
char device[UTIL_PATH_SIZE];
char *s;
size_t l;
ssize_t len;
struct udev_device *dev;
int maj, min;
char type;
if (ent->d_name[0] == '.')
continue;
s = device;
l = util_strpcpy(&s, sizeof(device), udev_get_sys_path(udev));
len = readlinkat(dirfd(dir), ent->d_name, s, l);
if (len <= 0 || len == (ssize_t)l)
goto unlink;
s[len] = '\0';
if (sscanf(s, "%c%i:%i", &type, &maj, &min) != 3)
goto unlink;
dev = udev_device_new_from_devnum(udev, type, makedev(maj, min));
if (dev == NULL)
goto unlink;
info(udev, "restoring old watch on '%s'\n", udev_device_get_devnode(dev));
udev_watch_begin(udev, dev);
udev_device_unref(dev);
unlink:
unlinkat(dirfd(dir), ent->d_name, 0);
}
closedir(dir);
rmdir(oldname);
} else if (errno != ENOENT) {
err(udev, "unable to move watches dir '%s', old watches will not be restored: %m", filename);
}
}
struct udev_device *udev_watch_lookup(struct udev *udev, int wd)
{
char filename[UTIL_PATH_SIZE];
char majmin[UTIL_PATH_SIZE];
char *s;
size_t l;
ssize_t len;
if (inotify_fd < 0 || wd < 0)
return NULL;
snprintf(filename, sizeof(filename), "%s/watch/%d", udev_get_run_path(udev), wd);
s = majmin;
l = util_strpcpy(&s, sizeof(majmin), udev_get_sys_path(udev));
len = readlink(filename, s, l);
if (len <= 0 || (size_t)len == l)
return NULL;
s[len] = '\0';
return udev_device_new_from_device_id(udev, s);
}
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_selinux(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_selinux(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;
}
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)) {
log_error("conflicting device node '%s' found, link to '%s' will not be created\n", slink, node);
goto exit;
} else if (S_ISLNK(stats.st_mode)) {
char buf[UTIL_PATH_SIZE];
int len;
len = readlink(slink, buf, sizeof(buf));
if (len > 0 && len < (int)sizeof(buf)) {
buf[len] = '\0';
if (strcmp(target, buf) == 0) {
log_debug("preserve already existing symlink '%s' to '%s'\n", slink, target);
label_fix(slink, true, false);
utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
goto exit;
}
}
}
} else {
log_debug("creating symlink '%s' to '%s'\n", slink, target);
do {
err = mkdir_parents_label(slink, 0755);
if (err != 0 && err != -ENOENT)
break;
label_context_set(slink, S_IFLNK);
err = symlink(target, slink);
if (err != 0)
err = -errno;
label_context_clear();
} while (err == -ENOENT);
if (err == 0)
goto exit;
}
log_debug("atomically replace '%s'\n", slink);
util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
unlink(slink_tmp);
do {
err = mkdir_parents_label(slink_tmp, 0755);
if (err != 0 && err != -ENOENT)
break;
label_context_set(slink_tmp, S_IFLNK);
err = symlink(target, slink_tmp);
if (err != 0)
err = -errno;
label_context_clear();
} while (err == -ENOENT);
if (err != 0) {
log_error("symlink '%s' '%s' failed: %m\n", target, slink_tmp);
goto exit;
}
err = rename(slink_tmp, slink);
if (err != 0) {
log_error("rename '%s' '%s' failed: %m\n", slink_tmp, slink);
unlink(slink_tmp);
}
exit:
return err;
}