release/src/router/busybox/e2fsprogs/blkid/resolve.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * resolve.c - resolve names and tags into specific devices
   4  *
   5  * Copyright (C) 2001, 2003 Theodore Ts'o.
   6  * Copyright (C) 2001 Andreas Dilger
   7  *
   8  * %Begin-Header%
   9  * This file may be redistributed under the terms of the
  10  * GNU Lesser General Public License.
  11  * %End-Header%
  12  */
  13
  14 #include <stdio.h>
  15 #ifdef HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #include <stdlib.h>
  19 #include <fcntl.h>
  20 #include <string.h>
  21 #include <sys/types.h>
  22 #include <sys/stat.h>
  23 #include "blkidP.h"
  24 #include "probe.h"
  25
  26 /*
  27  * Find a tagname (e.g. LABEL or UUID) on a specific device.
  28  */
  29 char *blkid_get_tag_value(blkid_cache cache, const char *tagname,
  30                           const char *devname)
  31 {
  32         blkid_tag found;
  33         blkid_dev dev;
  34         blkid_cache c = cache;
  35         char *ret = NULL;
  36
  37         DBG(DEBUG_RESOLVE, printf("looking for %s on %s\n", tagname, devname));
  38
  39         if (!devname)
  40                 return NULL;
  41
  42         if (!cache) {
  43                 if (blkid_get_cache(&c, NULL) < 0)
  44                         return NULL;
  45         }
  46
  47         if ((dev = blkid_get_dev(c, devname, BLKID_DEV_NORMAL)) &&
  48             (found = blkid_find_tag_dev(dev, tagname)))
  49                 ret = blkid_strdup(found->bit_val);
  50
  51         if (!cache)
  52                 blkid_put_cache(c);
  53
  54         return ret;
  55 }
  56
  57 /*
  58  * Locate a device name from a token (NAME=value string), or (name, value)
  59  * pair.  In the case of a token, value is ignored.  If the "token" is not
  60  * of the form "NAME=value" and there is no value given, then it is assumed
  61  * to be the actual devname and a copy is returned.
  62  */
  63 char *blkid_get_devname(blkid_cache cache, const char *token,
  64                         const char *value)
  65 {
  66         blkid_dev dev;
  67         blkid_cache c = cache;
  68         char *t = NULL, *v = NULL;
  69         char *ret = NULL;
  70
  71         if (!token)
  72                 return NULL;
  73
  74         if (!cache) {
  75                 if (blkid_get_cache(&c, NULL) < 0)
  76                         return NULL;
  77         }
  78
  79         DBG(DEBUG_RESOLVE,
  80             printf("looking for %s%s%s %s\n", token, value ? "=" : "",
  81                    value ? value : "", cache ? "in cache" : "from disk"));
  82
  83         if (!value) {
  84                 if (!strchr(token, '='))
  85                         return blkid_strdup(token);
  86                 blkid_parse_tag_string(token, &t, &v);
  87                 if (!t || !v)
  88                         goto errout;
  89                 token = t;
  90                 value = v;
  91         }
  92
  93         dev = blkid_find_dev_with_tag(c, token, value);
  94         if (!dev)
  95                 goto errout;
  96
  97         ret = blkid_strdup(blkid_dev_devname(dev));
  98
  99 errout:
 100         free(t);
 101         free(v);
 102         if (!cache) {
 103                 blkid_put_cache(c);
 104         }
 105         return ret;
 106 }
 107
 108 #ifdef TEST_PROGRAM
 109 int main(int argc, char **argv)
 110 {
 111         char *value;
 112         blkid_cache cache;
 113
 114         blkid_debug_mask = DEBUG_ALL;
 115         if (argc != 2 && argc != 3) {
 116                 fprintf(stderr, "Usage:\t%s tagname=value\n"
 117                         "\t%s tagname devname\n"
 118                         "Find which device holds a given token or\n"
 119                         "Find what the value of a tag is in a device\n",
 120                         argv[0], argv[0]);
 121                 exit(1);
 122         }
 123         if (blkid_get_cache(&cache, bb_dev_null) < 0) {
 124                 fprintf(stderr, "Can't get blkid cache\n");
 125                 exit(1);
 126         }
 127
 128         if (argv[2]) {
 129                 value = blkid_get_tag_value(cache, argv[1], argv[2]);
 130                 printf("%s has tag %s=%s\n", argv[2], argv[1],
 131                        value ? value : "<missing>");
 132         } else {
 133                 value = blkid_get_devname(cache, argv[1], NULL);
 134                 printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
 135         }
 136         blkid_put_cache(cache);
 137         return value ? 0 : 1;
 138 }
 139 #endif