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