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 */ 27char *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 */ 61char *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 99out: 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 111int 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