1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Support functions for mounting devices by label/uuid
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4 | *
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5 | * Copyright (C) 2006 by Jason Schoon <floydpink@gmail.com>
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6 | * Some portions cribbed from e2fsprogs, util-linux, dosfstools
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7 | *
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8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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9 | */
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10 | #include <sys/mount.h> /* BLKGETSIZE64 */
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11 | #if !defined(BLKGETSIZE64)
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12 | # define BLKGETSIZE64 _IOR(0x12,114,size_t)
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13 | #endif
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14 | #include "volume_id_internal.h"
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15 |
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16 | static struct uuidCache_s {
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17 | struct uuidCache_s *next;
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18 | // int major, minor;
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19 | char *device;
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20 | char *label;
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21 | char *uc_uuid; /* prefix makes it easier to grep for */
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22 | IF_FEATURE_BLKID_TYPE(const char *type;)
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23 | } *uuidCache;
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24 |
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25 | #if !ENABLE_FEATURE_BLKID_TYPE
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26 | #define get_label_uuid(fd, label, uuid, type) \
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27 | get_label_uuid(fd, label, uuid)
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28 | #define uuidcache_addentry(device, label, uuid, type) \
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29 | uuidcache_addentry(device, label, uuid)
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30 | #endif
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31 |
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32 | /* Returns !0 on error.
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33 | * Otherwise, returns malloc'ed strings for label and uuid
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34 | * (and they can't be NULL, although they can be "").
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35 | * NB: closes fd. */
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36 | static int
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37 | get_label_uuid(int fd, char **label, char **uuid, const char **type)
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38 | {
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39 | int rv = 1;
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40 | uint64_t size;
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41 | struct volume_id *vid;
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42 |
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43 | /* fd is owned by vid now */
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44 | vid = volume_id_open_node(fd);
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45 |
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46 | if (ioctl(/*vid->*/fd, BLKGETSIZE64, &size) != 0)
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47 | size = 0;
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48 |
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49 | if (volume_id_probe_all(vid, /*0,*/ size) != 0)
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50 | goto ret;
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51 |
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52 | if (vid->label[0] != '\0' || vid->uuid[0] != '\0'
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53 | #if ENABLE_FEATURE_BLKID_TYPE
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54 | || vid->type != NULL
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55 | #endif
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56 | ) {
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57 | *label = xstrndup(vid->label, sizeof(vid->label));
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58 | *uuid = xstrndup(vid->uuid, sizeof(vid->uuid));
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59 | #if ENABLE_FEATURE_BLKID_TYPE
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60 | *type = vid->type;
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61 | dbg("found label '%s', uuid '%s', type '%s'", *label, *uuid, *type);
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62 | #else
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63 | dbg("found label '%s', uuid '%s'", *label, *uuid);
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64 | #endif
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65 | rv = 0;
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66 | }
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67 | ret:
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68 | free_volume_id(vid); /* also closes fd */
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69 | return rv;
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70 | }
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71 |
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72 | /* NB: we take ownership of (malloc'ed) label and uuid */
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73 | static void
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74 | uuidcache_addentry(char *device, /*int major, int minor,*/ char *label, char *uuid, const char *type)
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75 | {
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76 | struct uuidCache_s *last;
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77 |
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78 | if (!uuidCache) {
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79 | last = uuidCache = xzalloc(sizeof(*uuidCache));
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80 | } else {
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81 | for (last = uuidCache; last->next; last = last->next)
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82 | continue;
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83 | last->next = xzalloc(sizeof(*uuidCache));
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84 | last = last->next;
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85 | }
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86 | /*last->next = NULL; - xzalloc did it*/
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87 | // last->major = major;
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88 | // last->minor = minor;
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89 | last->device = device;
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90 | last->label = label;
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91 | last->uc_uuid = uuid;
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92 | IF_FEATURE_BLKID_TYPE(last->type = type;)
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93 | }
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94 |
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95 | /* If get_label_uuid() on device_name returns success,
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96 | * add a cache entry for this device.
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97 | * If device node does not exist, it will be temporarily created. */
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98 | static int FAST_FUNC
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99 | uuidcache_check_device(const char *device,
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100 | struct stat *statbuf,
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101 | void *userData UNUSED_PARAM,
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102 | int depth UNUSED_PARAM)
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103 | {
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104 | /* note: this check rejects links to devices, among other nodes */
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105 | if (!S_ISBLK(statbuf->st_mode))
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106 | return TRUE;
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107 |
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108 | /* Users report that mucking with floppies (especially non-present
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109 | * ones) is significant PITA. This is a horribly dirty hack,
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110 | * but it is very useful in real world.
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111 | * If this will ever need to be enabled, consider using O_NONBLOCK.
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112 | */
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113 | if (major(statbuf->st_rdev) == 2)
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114 | return TRUE;
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115 |
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116 | add_to_uuid_cache(device);
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117 |
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118 | return TRUE;
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119 | }
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120 |
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121 | static struct uuidCache_s*
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122 | uuidcache_init(int scan_devices)
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123 | {
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124 | dbg("DBG: uuidCache=%x, uuidCache");
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125 | if (uuidCache)
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126 | return uuidCache;
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127 |
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128 | /* We were scanning /proc/partitions
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129 | * and /proc/sys/dev/cdrom/info here.
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130 | * Missed volume managers. I see that "standard" blkid uses these:
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131 | * /dev/mapper/control
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132 | * /proc/devices
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133 | * /proc/evms/volumes
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134 | * /proc/lvm/VGs
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135 | * This is unacceptably complex. Let's just scan /dev.
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136 | * (Maybe add scanning of /sys/block/XXX/dev for devices
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137 | * somehow not having their /dev/XXX entries created?) */
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138 | if (scan_devices)
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139 | recursive_action("/dev", ACTION_RECURSE,
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140 | uuidcache_check_device, /* file_action */
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141 | NULL, /* dir_action */
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142 | NULL, /* userData */
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143 | 0 /* depth */);
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144 |
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145 | return uuidCache;
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146 | }
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147 |
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148 | #define UUID 1
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149 | #define VOL 2
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150 |
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151 | #ifdef UNUSED
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152 | static char *
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153 | get_spec_by_x(int n, const char *t, int *majorPtr, int *minorPtr)
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154 | {
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155 | struct uuidCache_s *uc;
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156 |
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157 | uc = uuidcache_init(/*scan_devices:*/ 1);
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158 | while (uc) {
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159 | switch (n) {
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160 | case UUID:
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161 | if (strcmp(t, uc->uc_uuid) == 0) {
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162 | *majorPtr = uc->major;
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163 | *minorPtr = uc->minor;
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164 | return uc->device;
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165 | }
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166 | break;
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167 | case VOL:
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168 | if (strcmp(t, uc->label) == 0) {
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169 | *majorPtr = uc->major;
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170 | *minorPtr = uc->minor;
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171 | return uc->device;
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172 | }
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173 | break;
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174 | }
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175 | uc = uc->next;
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176 | }
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177 | return NULL;
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178 | }
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179 |
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180 | static unsigned char
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181 | fromhex(char c)
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182 | {
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183 | if (isdigit(c))
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184 | return (c - '0');
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185 | return ((c|0x20) - 'a' + 10);
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186 | }
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187 |
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188 | static char *
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189 | get_spec_by_uuid(const char *s, int *major, int *minor)
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190 | {
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191 | unsigned char uuid[16];
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192 | int i;
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193 |
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194 | if (strlen(s) != 36 || s[8] != '-' || s[13] != '-'
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195 | || s[18] != '-' || s[23] != '-'
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196 | ) {
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197 | goto bad_uuid;
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198 | }
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199 | for (i = 0; i < 16; i++) {
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200 | if (*s == '-')
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201 | s++;
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202 | if (!isxdigit(s[0]) || !isxdigit(s[1]))
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203 | goto bad_uuid;
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204 | uuid[i] = ((fromhex(s[0]) << 4) | fromhex(s[1]));
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205 | s += 2;
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206 | }
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207 | return get_spec_by_x(UUID, (char *)uuid, major, minor);
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208 |
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209 | bad_uuid:
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210 | fprintf(stderr, _("mount: bad UUID"));
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211 | return 0;
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212 | }
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213 |
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214 | static char *
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215 | get_spec_by_volume_label(const char *s, int *major, int *minor)
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216 | {
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217 | return get_spec_by_x(VOL, s, major, minor);
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218 | }
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219 | #endif // UNUSED
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220 |
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221 | /* Used by blkid */
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222 | void display_uuid_cache(int scan_devices)
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223 | {
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224 | struct uuidCache_s *uc;
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225 |
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226 | uc = uuidcache_init(scan_devices);
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227 | while (uc) {
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228 | printf("%s:", uc->device);
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229 | if (uc->label[0])
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230 | printf(" LABEL=\"%s\"", uc->label);
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231 | if (uc->uc_uuid[0])
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232 | printf(" UUID=\"%s\"", uc->uc_uuid);
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233 | #if ENABLE_FEATURE_BLKID_TYPE
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234 | if (uc->type)
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235 | printf(" TYPE=\"%s\"", uc->type);
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236 | #endif
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237 | bb_putchar('\n');
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238 | uc = uc->next;
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239 | }
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240 | }
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241 |
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242 | int add_to_uuid_cache(const char *device)
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243 | {
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244 | char *uuid = uuid; /* for compiler */
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245 | char *label = label;
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246 | #if ENABLE_FEATURE_BLKID_TYPE
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247 | const char *type = type;
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248 | #endif
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249 | int fd;
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250 |
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251 | fd = open(device, O_RDONLY);
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252 | if (fd < 0)
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253 | return 0;
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254 |
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255 | /* get_label_uuid() closes fd in all cases (success & failure) */
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256 | if (get_label_uuid(fd, &label, &uuid, &type) == 0) {
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257 | /* uuidcache_addentry() takes ownership of all four params */
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258 | uuidcache_addentry(xstrdup(device), /*ma, mi,*/ label, uuid, type);
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259 | return 1;
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260 | }
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261 | return 0;
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262 | }
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263 |
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264 |
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265 | /* Used by mount and findfs */
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266 |
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267 | char *get_devname_from_label(const char *spec)
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268 | {
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269 | struct uuidCache_s *uc;
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270 |
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271 | uc = uuidcache_init(/*scan_devices:*/ 1);
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272 | while (uc) {
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273 | if (uc->label[0] && strcmp(spec, uc->label) == 0) {
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274 | return xstrdup(uc->device);
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275 | }
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276 | uc = uc->next;
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277 | }
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278 | return NULL;
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279 | }
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280 |
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281 | char *get_devname_from_uuid(const char *spec)
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282 | {
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283 | struct uuidCache_s *uc;
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284 |
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285 | uc = uuidcache_init(/*scan_devices:*/ 1);
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286 | while (uc) {
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287 | /* case of hex numbers doesn't matter */
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288 | if (strcasecmp(spec, uc->uc_uuid) == 0) {
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289 | return xstrdup(uc->device);
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290 | }
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291 | uc = uc->next;
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292 | }
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293 | return NULL;
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294 | }
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295 |
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296 | int resolve_mount_spec(char **fsname)
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297 | {
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298 | char *tmp = *fsname;
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299 |
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300 | if (strncmp(*fsname, "UUID=", 5) == 0)
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301 | tmp = get_devname_from_uuid(*fsname + 5);
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302 | else if (strncmp(*fsname, "LABEL=", 6) == 0)
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303 | tmp = get_devname_from_label(*fsname + 6);
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304 |
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305 | if (tmp == *fsname)
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306 | return 0; /* no UUID= or LABEL= prefix found */
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307 |
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308 | if (tmp)
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309 | *fsname = tmp;
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310 | return 1;
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311 | }
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