1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | *
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4 | * mdev - Mini udev for busybox
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5 | *
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6 | * Copyright 2005 Rob Landley <rob@landley.net>
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7 | * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
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8 | *
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9 | * Licensed under GPL version 2, see file LICENSE in this tarball for details.
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10 | */
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11 |
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12 | #include "libbb.h"
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13 | #include "xregex.h"
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14 |
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15 | struct globals {
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16 | int root_major, root_minor;
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17 | };
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18 | #define G (*(struct globals*)&bb_common_bufsiz1)
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19 | #define root_major (G.root_major)
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20 | #define root_minor (G.root_minor)
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21 |
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22 | #define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
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23 |
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24 | /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
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25 | static void make_device(char *path, int delete)
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26 | {
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27 | const char *device_name;
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28 | int major, minor, type, len;
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29 | int mode = 0660;
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30 | uid_t uid = 0;
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31 | gid_t gid = 0;
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32 | char *temp = path + strlen(path);
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33 | char *command = NULL;
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34 |
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35 | /* Try to read major/minor string. Note that the kernel puts \n after
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36 | * the data, so we don't need to worry about null terminating the string
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37 | * because sscanf() will stop at the first nondigit, which \n is. We
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38 | * also depend on path having writeable space after it. */
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39 |
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40 | if (!delete) {
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41 | strcat(path, "/dev");
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42 | len = open_read_close(path, temp + 1, 64);
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43 | *temp++ = 0;
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44 | if (len < 1) return;
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45 | }
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46 |
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47 | /* Determine device name, type, major and minor */
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48 |
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49 | device_name = bb_basename(path);
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50 | type = path[5]=='c' ? S_IFCHR : S_IFBLK;
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51 |
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52 | /* If we have a config file, look up permissions for this device */
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53 |
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54 | if (ENABLE_FEATURE_MDEV_CONF) {
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55 | char *conf, *pos, *end;
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56 | int line, fd;
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57 |
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58 | /* mmap the config file */
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59 | fd = open("/etc/mdev.conf", O_RDONLY);
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60 | if (fd < 0)
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61 | goto end_parse;
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62 | len = xlseek(fd, 0, SEEK_END);
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63 | conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
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64 | close(fd);
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65 | if (!conf)
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66 | goto end_parse;
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67 |
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68 | line = 0;
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69 | /* Loop through lines in mmaped file*/
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70 | for (pos=conf; pos-conf<len;) {
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71 | int field;
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72 | char *end2;
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73 |
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74 | line++;
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75 | /* find end of this line */
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76 | for (end=pos; end-conf<len && *end!='\n'; end++)
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77 | ;
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78 |
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79 | /* Three fields: regex, uid:gid, mode */
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80 | for (field=0; field < (3 + ENABLE_FEATURE_MDEV_EXEC);
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81 | field++)
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82 | {
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83 | /* Skip whitespace */
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84 | while (pos<end && isspace(*pos)) pos++;
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85 | if (pos==end || *pos=='#') break;
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86 | for (end2=pos;
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87 | end2<end && !isspace(*end2) && *end2!='#'; end2++)
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88 | ;
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89 |
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90 | if (field == 0) {
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91 | /* Regex to match this device */
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92 |
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93 | char *regex = xstrndup(pos, end2-pos);
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94 | regex_t match;
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95 | regmatch_t off;
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96 | int result;
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97 |
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98 | /* Is this it? */
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99 | xregcomp(&match,regex, REG_EXTENDED);
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100 | result = regexec(&match, device_name, 1, &off, 0);
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101 | regfree(&match);
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102 | free(regex);
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103 |
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104 | /* If not this device, skip rest of line */
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105 | if (result || off.rm_so
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106 | || off.rm_eo != strlen(device_name))
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107 | break;
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108 | }
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109 | if (field == 1) {
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110 | /* uid:gid */
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111 |
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112 | char *s, *s2;
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113 |
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114 | /* Find : */
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115 | for (s=pos; s<end2 && *s!=':'; s++)
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116 | ;
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117 | if (s == end2) break;
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118 |
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119 | /* Parse UID */
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120 | uid = strtoul(pos, &s2, 10);
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121 | if (s != s2) {
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122 | struct passwd *pass;
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123 | char *_unam = xstrndup(pos, s-pos);
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124 | pass = getpwnam(_unam);
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125 | free(_unam);
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126 | if (!pass) break;
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127 | uid = pass->pw_uid;
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128 | }
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129 | s++;
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130 | /* parse GID */
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131 | gid = strtoul(s, &s2, 10);
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132 | if (end2 != s2) {
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133 | struct group *grp;
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134 | char *_grnam = xstrndup(s, end2-s);
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135 | grp = getgrnam(_grnam);
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136 | free(_grnam);
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137 | if (!grp) break;
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138 | gid = grp->gr_gid;
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139 | }
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140 | }
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141 | if (field == 2) {
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142 | /* mode */
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143 |
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144 | mode = strtoul(pos, &pos, 8);
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145 | if (pos != end2) break;
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146 | }
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147 | if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
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148 | // Command to run
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149 | const char *s = "@$*";
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150 | const char *s2;
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151 | s2 = strchr(s, *pos++);
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152 | if (!s2) {
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153 | // Force error
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154 | field = 1;
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155 | break;
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156 | }
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157 | if ((s2-s+1) & (1<<delete))
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158 | command = xstrndup(pos, end-pos);
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159 | }
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160 |
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161 | pos = end2;
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162 | }
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163 |
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164 | /* Did everything parse happily? */
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165 |
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166 | if (field > 2) break;
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167 | if (field) bb_error_msg_and_die("bad line %d",line);
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168 |
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169 | /* Next line */
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170 | pos = ++end;
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171 | }
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172 | munmap(conf, len);
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173 | end_parse: /* nothing */ ;
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174 | }
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175 |
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176 | umask(0);
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177 | if (!delete) {
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178 | if (sscanf(temp, "%d:%d", &major, &minor) != 2) return;
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179 | if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
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180 | bb_perror_msg_and_die("mknod %s", device_name);
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181 |
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182 | if (major == root_major && minor == root_minor)
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183 | symlink(device_name, "root");
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184 |
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185 | if (ENABLE_FEATURE_MDEV_CONF) chown(device_name, uid, gid);
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186 | }
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187 | if (command) {
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188 | /* setenv will leak memory, so use putenv */
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189 | char *s = xasprintf("MDEV=%s", device_name);
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190 | putenv(s);
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191 | if (system(command) == -1)
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192 | bb_perror_msg_and_die("cannot run %s", command);
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193 | s[4] = '\0';
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194 | unsetenv(s);
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195 | free(s);
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196 | free(command);
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197 | }
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198 | if (delete) unlink(device_name);
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199 | }
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200 |
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201 | /* File callback for /sys/ traversal */
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202 | static int fileAction(const char *fileName, struct stat *statbuf,
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203 | void *userData, int depth)
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204 | {
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205 | size_t len = strlen(fileName) - 4;
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206 | char *scratch = userData;
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207 |
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208 | if (strcmp(fileName + len, "/dev"))
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209 | return FALSE;
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210 |
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211 | strcpy(scratch, fileName);
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212 | scratch[len] = 0;
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213 | make_device(scratch, 0);
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214 |
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215 | return TRUE;
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216 | }
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217 |
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218 | /* Directory callback for /sys/ traversal */
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219 | static int dirAction(const char *fileName, struct stat *statbuf,
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220 | void *userData, int depth)
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221 | {
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222 | return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
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223 | }
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224 |
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225 | /* For the full gory details, see linux/Documentation/firmware_class/README
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226 | *
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227 | * Firmware loading works like this:
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228 | * - kernel sets FIRMWARE env var
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229 | * - userspace checks /lib/firmware/$FIRMWARE
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230 | * - userspace waits for /sys/$DEVPATH/loading to appear
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231 | * - userspace writes "1" to /sys/$DEVPATH/loading
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232 | * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
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233 | * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
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234 | * - kernel loads firmware into device
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235 | */
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236 | static void load_firmware(const char *const firmware, const char *const sysfs_path)
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237 | {
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238 | int cnt;
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239 | int firmware_fd, loading_fd, data_fd;
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240 |
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241 | /* check for $FIRMWARE from kernel */
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242 | /* XXX: dont bother: open(NULL) works same as open("no-such-file")
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243 | * if (!firmware)
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244 | * return;
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245 | */
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246 |
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247 | /* check for /lib/firmware/$FIRMWARE */
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248 | xchdir("/lib/firmware");
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249 | firmware_fd = xopen(firmware, O_RDONLY);
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250 |
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251 | /* in case we goto out ... */
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252 | data_fd = -1;
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253 |
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254 | /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
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255 | xchdir(sysfs_path);
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256 | for (cnt = 0; cnt < 30; ++cnt) {
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257 | loading_fd = open("loading", O_WRONLY);
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258 | if (loading_fd == -1)
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259 | sleep(1);
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260 | else
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261 | break;
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262 | }
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263 | if (loading_fd == -1)
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264 | goto out;
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265 |
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266 | /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
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267 | if (write(loading_fd, "1", 1) != 1)
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268 | goto out;
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269 |
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270 | /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
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271 | data_fd = open("data", O_WRONLY);
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272 | if (data_fd == -1)
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273 | goto out;
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274 | cnt = bb_copyfd_eof(firmware_fd, data_fd);
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275 |
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276 | /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
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277 | if (cnt > 0)
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278 | write(loading_fd, "0", 1);
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279 | else
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280 | write(loading_fd, "-1", 2);
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281 |
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282 | out:
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283 | if (ENABLE_FEATURE_CLEAN_UP) {
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284 | close(firmware_fd);
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285 | close(loading_fd);
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286 | close(data_fd);
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287 | }
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288 | }
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289 |
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290 | int mdev_main(int argc, char **argv);
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291 | int mdev_main(int argc, char **argv)
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292 | {
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293 | char *action;
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294 | char *env_path;
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295 | RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
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296 |
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297 | xchdir("/dev");
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298 |
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299 | /* Scan */
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300 |
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301 | if (argc == 2 && !strcmp(argv[1],"-s")) {
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302 | struct stat st;
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303 |
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304 | xstat("/", &st);
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305 | root_major = major(st.st_dev);
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306 | root_minor = minor(st.st_dev);
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307 |
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308 | recursive_action("/sys/block",
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309 | ACTION_RECURSE | ACTION_FOLLOWLINKS,
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310 | fileAction, dirAction, temp, 0);
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311 |
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312 | recursive_action("/sys/class",
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313 | ACTION_RECURSE | ACTION_FOLLOWLINKS,
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314 | fileAction, dirAction, temp, 0);
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315 |
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316 | /* Hotplug */
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317 |
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318 | } else {
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319 | action = getenv("ACTION");
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320 | env_path = getenv("DEVPATH");
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321 | if (!action || !env_path)
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322 | bb_show_usage();
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323 |
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324 | sprintf(temp, "/sys%s", env_path);
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325 | if (!strcmp(action, "remove"))
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326 | make_device(temp, 1);
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327 | else if (!strcmp(action, "add")) {
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328 | make_device(temp, 0);
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329 |
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330 | if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
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331 | load_firmware(getenv("FIRMWARE"), temp);
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332 | }
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333 | }
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334 |
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335 | if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);
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336 | return 0;
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337 | }
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