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 "config.h"
14 #include <stdio.h>
15 #if 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
25 /*
26 * Find a tagname (e.g. LABEL or UUID) on a specific device.
27 */
blkid_get_tag_value(blkid_cache cache,const char * tagname,const char * devname)28 char *blkid_get_tag_value(blkid_cache cache, const char *tagname,
29 const char *devname)
30 {
31 blkid_tag found;
32 blkid_dev dev;
33 blkid_cache c = cache;
34 char *ret = NULL;
35
36 DBG(DEBUG_RESOLVE, printf("looking for %s on %s\n", tagname, devname));
37
38 if (!devname)
39 return NULL;
40
41 if (!cache) {
42 if (blkid_get_cache(&c, NULL) < 0)
43 return NULL;
44 }
45
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);
49
50 if (!cache)
51 blkid_put_cache(c);
52
53 return ret;
54 }
55
56 /*
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.
61 */
blkid_get_devname(blkid_cache cache,const char * token,const char * value)62 char *blkid_get_devname(blkid_cache cache, const char *token,
63 const char *value)
64 {
65 blkid_dev dev;
66 blkid_cache c = cache;
67 char *t = 0, *v = 0;
68 char *ret = NULL;
69
70 if (!token)
71 return NULL;
72
73 if (!cache) {
74 if (blkid_get_cache(&c, NULL) < 0)
75 return NULL;
76 }
77
78 DBG(DEBUG_RESOLVE,
79 printf("looking for %s%s%s %s\n", token, value ? "=" : "",
80 value ? value : "", cache ? "in cache" : "from disk"));
81
82 if (!value) {
83 if (!strchr(token, '=')) {
84 ret = blkid_strdup(token);
85 goto out;
86 }
87 blkid_parse_tag_string(token, &t, &v);
88 if (!t || !v)
89 goto out;
90 token = t;
91 value = v;
92 }
93
94 dev = blkid_find_dev_with_tag(c, token, value);
95 if (!dev)
96 goto out;
97
98 ret = blkid_strdup(blkid_dev_devname(dev));
99
100 out:
101 free(t);
102 free(v);
103 if (!cache) {
104 blkid_put_cache(c);
105 }
106 return (ret);
107 }
108
109 #ifdef TEST_PROGRAM
main(int argc,char ** argv)110 int main(int argc, char **argv)
111 {
112 char *value;
113 blkid_cache cache;
114
115 blkid_debug_mask = DEBUG_ALL;
116 if (argc != 2 && argc != 3) {
117 fprintf(stderr, "Usage:\t%s tagname=value\n"
118 "\t%s tagname devname\n"
119 "Find which device holds a given token or\n"
120 "Find what the value of a tag is in a device\n",
121 argv[0], argv[0]);
122 exit(1);
123 }
124 if (blkid_get_cache(&cache, "/dev/null") < 0) {
125 fprintf(stderr, "Couldn't get blkid cache\n");
126 exit(1);
127 }
128
129 if (argv[2]) {
130 value = blkid_get_tag_value(cache, argv[1], argv[2]);
131 printf("%s has tag %s=%s\n", argv[2], argv[1],
132 value ? value : "<missing>");
133 } else {
134 value = blkid_get_devname(cache, argv[1], NULL);
135 printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
136 }
137 blkid_put_cache(cache);
138 return value ? 0 : 1;
139 }
140 #endif
141