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 */ 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 */ 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 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