lib/support/devname.c

   1 /*
   2  * devname.c --- Support function to translate a user provided string
   3  * identifying a device to an actual device path
   4  *
   5  * Copyright (C) 2022 Red Hat, Inc., Lukas Czerner <lczerner@redhat.com>
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Public
   9  * License.
  10  * %End-Header%
  11  */
  12
  13 #include <unistd.h>
  14 #include <string.h>
  15 #include <stdio.h>
  16
  17 #include "config.h"
  18 #include "devname.h"
  19 #include "nls-enable.h"
  20
  21 /*
  22  *  blkid_get_devname() is primarily intended for parsing "NAME=value"
  23  *  tokens. It will return the device matching the specified token, NULL if
  24  *  nothing is found, or copy of the string if it's not in "NAME=value"
  25  *  format.
  26  *  get_devname() takes the same parameters and works the same way as
  27  *  blkid_get_devname() except it can handle '=' in the file name.
  28  */
  29 char *get_devname(blkid_cache cache, const char *token, const char *value)
  30 {
  31         int is_file = 0;
  32         char *ret = NULL;
  33
  34         if (!token)
  35                 goto out;
  36
  37         if (value) {
  38                 ret = blkid_get_devname(cache, token, value);
  39                 goto out;
  40         }
  41
  42         if (access(token, F_OK) == 0)
  43                 is_file = 1;
  44
  45         ret = blkid_get_devname(cache, token, NULL);
  46         if (ret) {
  47                 /*
  48                  * In case of collision prefer the result from
  49                  * blkid_get_devname() to avoid a file masking file system with
  50                  * existing tag.
  51                  */
  52                 if (is_file && (strcmp(ret, token) != 0)) {
  53                         fprintf(stderr,
  54                                 _("Collision found: '%s' refers to both '%s' "
  55                                   "and a file '%s'. Using '%s'!\n"),
  56                                 token, ret, token, ret);
  57                 }
  58                 goto out;
  59         }
  60
  61         if (is_file)
  62                 ret = strdup(token);
  63 out:
  64         return ret;
  65 }