2 * resolve.c - resolve names and tags into specific devices
4 * Copyright (C) 2001, 2003 Theodore Ts'o.
5 * Copyright (C) 2001 Andreas Dilger
8 * This file may be redistributed under the terms of the
9 * GNU Lesser General Public License.
20 #include <sys/types.h>
26 * Find a tagname (e.g. LABEL or UUID) on a specific device.
28 char *blkid_get_tag_value(blkid_cache cache, const char *tagname,
33 blkid_cache c = cache;
36 DBG(DEBUG_RESOLVE, printf("looking for %s on %s\n", tagname, devname));
42 if (blkid_get_cache(&c, NULL) < 0)
46 if ((dev = blkid_get_dev(c, devname, BLKID_DEV_NORMAL)) &&
47 (found = blkid_find_tag_dev(dev, tagname)))
48 ret = blkid_strdup(found->bit_val);
57 * Locate a device name from a token (NAME=value string), or (name, value)
58 * pair. In the case of a token, value is ignored. If the "token" is not
59 * of the form "NAME=value" and there is no value given, then it is assumed
60 * to be the actual devname and a copy is returned.
62 char *blkid_get_devname(blkid_cache cache, const char *token,
66 blkid_cache c = cache;
74 if (blkid_get_cache(&c, NULL) < 0)
79 printf("looking for %s%s%s %s\n", token, value ? "=" : "",
80 value ? value : "", cache ? "in cache" : "from disk"));
83 if (!strchr(token, '='))
84 return blkid_strdup(token);
85 blkid_parse_tag_string(token, &t, &v);
92 dev = blkid_find_dev_with_tag(c, token, value);
96 ret = blkid_strdup(blkid_dev_devname(dev));
108 int main(int argc, char **argv)
113 blkid_debug_mask = DEBUG_ALL;
114 if (argc != 2 && argc != 3) {
115 fprintf(stderr, "Usage:\t%s tagname=value\n"
116 "\t%s tagname devname\n"
117 "Find which device holds a given token or\n"
118 "Find what the value of a tag is in a device\n",
122 if (blkid_get_cache(&cache, bb_dev_null) < 0) {
123 fprintf(stderr, "Couldn't get blkid cache\n");
128 value = blkid_get_tag_value(cache, argv[1], argv[2]);
129 printf("%s has tag %s=%s\n", argv[2], argv[1],
130 value ? value : "<missing>");
132 value = blkid_get_devname(cache, argv[1], NULL);
133 printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
135 blkid_put_cache(cache);
136 return value ? 0 : 1;