LXR busybox/e2fsprogs/old_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 */
  29char *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 */
  63char *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
  99errout:
 100        free(t);
 101        free(v);
 102        if (!cache) {
 103                blkid_put_cache(c);
 104        }
 105        return ret;
 106}
 107
 108#ifdef TEST_PROGRAM
 109int 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
 140