1 /*
2 * resolve.c - resolve names and tags into specific devices
3 *
4 * Copyright (C) 2001, 2003 Theodore Ts'o.
5 * Copyright (C) 2001 Andreas Dilger
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the
9 * GNU Lesser General Public License.
10 * %End-Header%
11 */
12
13 #include <stdio.h>
14 #if HAVE_UNISTD_H
15 #include <unistd.h>
16 #endif
17 #include <stdlib.h>
18 #include <fcntl.h>
19 #include <string.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include "blkidP.h"
23
24 /*
25 * Find a tagname (e.g. LABEL or UUID) on a specific device.
26 */
blkid_get_tag_value(blkid_cache cache,const char * tagname,const char * devname)27 char *blkid_get_tag_value(blkid_cache cache, const char *tagname,
28 const char *devname)
29 {
30 blkid_tag found;
31 blkid_dev dev;
32 blkid_cache c = cache;
33 char *ret = NULL;
34
35 DBG(DEBUG_RESOLVE, printf("looking for %s on %s\n", tagname, devname));
36
37 if (!devname)
38 return NULL;
39
40 if (!cache) {
41 if (blkid_get_cache(&c, NULL) < 0)
42 return NULL;
43 }
44
45 if ((dev = blkid_get_dev(c, devname, BLKID_DEV_NORMAL)) &&
46 (found = blkid_find_tag_dev(dev, tagname)))
47 ret = blkid_strdup(found->bit_val);
48
49 if (!cache)
50 blkid_put_cache(c);
51
52 return ret;
53 }
54
55 /*
56 * Locate a device name from a token (NAME=value string), or (name, value)
57 * pair. In the case of a token, value is ignored. If the "token" is not
58 * of the form "NAME=value" and there is no value given, then it is assumed
59 * to be the actual devname and a copy is returned.
60 */
blkid_get_devname(blkid_cache cache,const char * token,const char * value)61 char *blkid_get_devname(blkid_cache cache, const char *token,
62 const char *value)
63 {
64 blkid_dev dev;
65 blkid_cache c = cache;
66 char *t = 0, *v = 0;
67 char *ret = NULL;
68
69 if (!token)
70 return NULL;
71
72 if (!cache) {
73 if (blkid_get_cache(&c, NULL) < 0)
74 return NULL;
75 }
76
77 DBG(DEBUG_RESOLVE,
78 printf("looking for %s%s%s %s\n", token, value ? "=" : "",
79 value ? value : "", cache ? "in cache" : "from disk"));
80
81 if (!value) {
82 if (!strchr(token, '=')) {
83 ret = blkid_strdup(token);
84 goto out;
85 }
86 blkid_parse_tag_string(token, &t, &v);
87 if (!t || !v)
88 goto out;
89 token = t;
90 value = v;
91 }
92
93 dev = blkid_find_dev_with_tag(c, token, value);
94 if (!dev)
95 goto out;
96
97 ret = blkid_strdup(blkid_dev_devname(dev));
98
99 out:
100 if (t)
101 free(t);
102 if (v)
103 free(v);
104 if (!cache) {
105 blkid_put_cache(c);
106 }
107 return (ret);
108 }
109
110 #ifdef TEST_PROGRAM
main(int argc,char ** argv)111 int main(int argc, char **argv)
112 {
113 char *value;
114 blkid_cache cache;
115
116 blkid_debug_mask = DEBUG_ALL;
117 if (argc != 2 && argc != 3) {
118 fprintf(stderr, "Usage:\t%s tagname=value\n"
119 "\t%s tagname devname\n"
120 "Find which device holds a given token or\n"
121 "Find what the value of a tag is in a device\n",
122 argv[0], argv[0]);
123 exit(1);
124 }
125 if (blkid_get_cache(&cache, "/dev/null") < 0) {
126 fprintf(stderr, "Couldn't get blkid cache\n");
127 exit(1);
128 }
129
130 if (argv[2]) {
131 value = blkid_get_tag_value(cache, argv[1], argv[2]);
132 printf("%s has tag %s=%s\n", argv[2], argv[1],
133 value ? value : "<missing>");
134 } else {
135 value = blkid_get_devname(cache, argv[1], NULL);
136 printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
137 }
138 blkid_put_cache(cache);
139 return value ? 0 : 1;
140 }
141 #endif
142