src/udev/udevadm-util.c

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2
   3 #include <errno.h>
   4
   5 #include "alloc-util.h"
   6 #include "device-private.h"
   7 #include "path-util.h"
   8 #include "udevadm-util.h"
   9 #include "unit-name.h"
  10
  11 int find_device(const char *id, const char *prefix, sd_device **ret) {
  12         _cleanup_free_ char *path = NULL;
  13         int r;
  14
  15         assert(id);
  16         assert(ret);
  17
  18         if (prefix) {
  19                 if (!path_startswith(id, prefix)) {
  20                         id = path = path_join(prefix, id);
  21                         if (!path)
  22                                 return -ENOMEM;
  23                 }
  24         } else {
  25                 /* In cases where the argument is generic (no prefix specified),
  26                  * check if the argument looks like a device unit name. */
  27                 if (unit_name_is_valid(id, UNIT_NAME_PLAIN) &&
  28                     unit_name_to_type(id) == UNIT_DEVICE) {
  29                         r = unit_name_to_path(id, &path);
  30                         if (r < 0)
  31                                 return log_debug_errno(r, "Failed to convert \"%s\" to a device path: %m", id);
  32                         id = path;
  33                 }
  34         }
  35
  36         if (path_startswith(id, "/sys/"))
  37                 return sd_device_new_from_syspath(ret, id);
  38
  39         if (path_startswith(id, "/dev/")) {
  40                 struct stat st;
  41
  42                 if (stat(id, &st) < 0)
  43                         return -errno;
  44
  45                 return device_new_from_stat_rdev(ret, &st);
  46         }
  47
  48         return -EINVAL;
  49 }