1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Mini id implementation for busybox
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4 | *
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5 | * Copyright (C) 2000 by Randolph Chung <tausq@debian.org>
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6 | * Copyright (C) 2008 by Tito Ragusa <farmatito@tiscali.it>
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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 |
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11 | /* BB_AUDIT SUSv3 compliant. */
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12 | /* Hacked by Tito Ragusa (C) 2004 to handle usernames of whatever
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13 | * length and to be more similar to GNU id.
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14 | * -Z option support: by Yuichi Nakamura <ynakam@hitachisoft.jp>
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15 | * Added -G option Tito Ragusa (C) 2008 for SUSv3.
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16 | */
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17 |
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18 | //config:config ID
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19 | //config: bool "id"
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20 | //config: default y
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21 | //config: help
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22 | //config: id displays the current user and group ID names.
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23 |
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24 | //config:config GROUPS
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25 | //config: bool "groups"
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26 | //config: default y
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27 | //config: help
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28 | //config: Print the group names associated with current user id.
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29 |
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30 | //kbuild:lib-$(CONFIG_GROUPS) += id.o
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31 | //kbuild:lib-$(CONFIG_ID) += id.o
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32 |
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33 | //applet:IF_GROUPS(APPLET_NOEXEC(groups, id, BB_DIR_USR_BIN, BB_SUID_DROP, groups))
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34 | //applet:IF_ID( APPLET_NOEXEC(id, id, BB_DIR_USR_BIN, BB_SUID_DROP, id ))
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35 |
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36 | //usage:#define id_trivial_usage
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37 | //usage: "[OPTIONS] [USER]"
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38 | //usage:#define id_full_usage "\n\n"
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39 | //usage: "Print information about USER or the current user\n"
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40 | //usage: IF_SELINUX(
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41 | //usage: "\n -Z Security context"
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42 | //usage: )
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43 | //usage: "\n -u User ID"
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44 | //usage: "\n -g Group ID"
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45 | //usage: "\n -G Supplementary group IDs"
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46 | //usage: "\n -n Print names instead of numbers"
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47 | //usage: "\n -r Print real ID instead of effective ID"
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48 | //usage:
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49 | //usage:#define id_example_usage
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50 | //usage: "$ id\n"
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51 | //usage: "uid=1000(andersen) gid=1000(andersen)\n"
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52 |
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53 | //usage:#define groups_trivial_usage
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54 | //usage: "[USER]"
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55 | //usage:#define groups_full_usage "\n\n"
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56 | //usage: "Print the group memberships of USER or for the current process"
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57 | //usage:
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58 | //usage:#define groups_example_usage
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59 | //usage: "$ groups\n"
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60 | //usage: "andersen lp dialout cdrom floppy\n"
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61 |
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62 | #include "libbb.h"
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63 |
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64 | /* This is a NOEXEC applet. Be very careful! */
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65 |
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66 | #if !ENABLE_USE_BB_PWD_GRP
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67 | #if defined(__UCLIBC_MAJOR__) && (__UCLIBC_MAJOR__ == 0)
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68 | #if (__UCLIBC_MINOR__ < 9) || (__UCLIBC_MINOR__ == 9 && __UCLIBC_SUBLEVEL__ < 30)
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69 | #error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
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70 | #endif
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71 | #endif
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72 | #endif
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73 |
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74 | enum {
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75 | PRINT_REAL = (1 << 0),
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76 | NAME_NOT_NUMBER = (1 << 1),
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77 | JUST_USER = (1 << 2),
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78 | JUST_GROUP = (1 << 3),
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79 | JUST_ALL_GROUPS = (1 << 4),
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80 | #if ENABLE_SELINUX
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81 | JUST_CONTEXT = (1 << 5),
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82 | #endif
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83 | };
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84 |
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85 | static int print_common(unsigned id, const char *name, const char *prefix)
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86 | {
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87 | if (prefix) {
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88 | printf("%s", prefix);
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89 | }
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90 | if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
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91 | printf("%u", id);
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92 | }
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93 | if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
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94 | if (name) {
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95 | printf(option_mask32 ? "%s" : "(%s)", name);
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96 | } else {
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97 | /* Don't set error status flag in default mode */
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98 | if (option_mask32) {
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99 | if (ENABLE_DESKTOP)
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100 | bb_error_msg("unknown ID %u", id);
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101 | return EXIT_FAILURE;
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102 | }
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103 | }
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104 | }
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105 | return EXIT_SUCCESS;
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106 | }
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107 |
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108 | static int print_group(gid_t id, const char *prefix)
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109 | {
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110 | return print_common(id, gid2group(id), prefix);
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111 | }
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112 |
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113 | static int print_user(uid_t id, const char *prefix)
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114 | {
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115 | return print_common(id, uid2uname(id), prefix);
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116 | }
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117 |
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118 | /* On error set *n < 0 and return >= 0
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119 | * If *n is too small, update it and return < 0
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120 | * (ok to trash groups[] in both cases)
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121 | * Otherwise fill in groups[] and return >= 0
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122 | */
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123 | static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
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124 | {
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125 | int m;
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126 |
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127 | if (username) {
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128 | /* If the user is a member of more than
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129 | * *n groups, then -1 is returned. Otherwise >= 0.
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130 | * (and no defined way of detecting errors?!) */
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131 | m = getgrouplist(username, rgid, groups, n);
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132 | /* I guess *n < 0 might indicate error. Anyway,
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133 | * malloc'ing -1 bytes won't be good, so: */
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134 | if (*n < 0)
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135 | return 0;
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136 | return m;
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137 | }
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138 |
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139 | *n = getgroups(*n, groups);
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140 | if (*n >= 0)
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141 | return *n;
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142 | /* Error */
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143 | if (errno == EINVAL) /* *n is too small? */
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144 | *n = getgroups(0, groups); /* get needed *n */
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145 | /* if *n >= 0, return -1 (got new *n), else return 0 (error): */
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146 | return -(*n >= 0);
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147 | }
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148 |
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149 | int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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150 | int id_main(int argc UNUSED_PARAM, char **argv)
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151 | {
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152 | uid_t ruid;
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153 | gid_t rgid;
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154 | uid_t euid;
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155 | gid_t egid;
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156 | unsigned opt;
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157 | int i;
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158 | int status = EXIT_SUCCESS;
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159 | const char *prefix;
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160 | const char *username;
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161 | #if ENABLE_SELINUX
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162 | security_context_t scontext = NULL;
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163 | #endif
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164 |
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165 | if (ENABLE_GROUPS && (!ENABLE_ID || applet_name[0] == 'g')) {
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166 | /* TODO: coreutils groups prepend "USER : " prefix,
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167 | * and accept many usernames. Example:
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168 | * # groups root root
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169 | * root : root
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170 | * root : root
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171 | */
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172 | opt = option_mask32 = getopt32(argv, "") | JUST_ALL_GROUPS | NAME_NOT_NUMBER;
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173 | } else {
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174 | /* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
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175 | /* Don't allow more than one username */
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176 | opt_complementary = "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
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177 | IF_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G");
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178 | opt = getopt32(argv, "rnugG" IF_SELINUX("Z"));
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179 | }
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180 |
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181 | username = argv[optind];
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182 | if (username) {
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183 | struct passwd *p = xgetpwnam(username);
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184 | euid = ruid = p->pw_uid;
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185 | egid = rgid = p->pw_gid;
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186 | } else {
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187 | egid = getegid();
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188 | rgid = getgid();
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189 | euid = geteuid();
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190 | ruid = getuid();
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191 | }
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192 | /* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
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193 | /* id says: print the real ID instead of the effective ID, with -ugG */
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194 | /* in fact in this case egid is always printed if egid != rgid */
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195 | if (!opt || (opt & JUST_ALL_GROUPS)) {
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196 | gid_t *groups;
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197 | int n;
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198 |
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199 | if (!opt) {
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200 | /* Default Mode */
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201 | status |= print_user(ruid, "uid=");
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202 | status |= print_group(rgid, " gid=");
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203 | if (euid != ruid)
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204 | status |= print_user(euid, " euid=");
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205 | if (egid != rgid)
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206 | status |= print_group(egid, " egid=");
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207 | } else {
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208 | /* JUST_ALL_GROUPS */
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209 | status |= print_group(rgid, NULL);
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210 | if (egid != rgid)
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211 | status |= print_group(egid, " ");
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212 | }
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213 | /* We are supplying largish buffer, trying
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214 | * to not run get_groups() twice. That might be slow
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215 | * ("user database in remote SQL server" case) */
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216 | groups = xmalloc(64 * sizeof(groups[0]));
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217 | n = 64;
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218 | if (get_groups(username, rgid, groups, &n) < 0) {
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219 | /* Need bigger buffer after all */
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220 | groups = xrealloc(groups, n * sizeof(groups[0]));
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221 | get_groups(username, rgid, groups, &n);
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222 | }
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223 | if (n > 0) {
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224 | /* Print the list */
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225 | prefix = " groups=";
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226 | for (i = 0; i < n; i++) {
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227 | if (opt && (groups[i] == rgid || groups[i] == egid))
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228 | continue;
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229 | status |= print_group(groups[i], opt ? " " : prefix);
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230 | prefix = ",";
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231 | }
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232 | } else if (n < 0) { /* error in get_groups() */
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233 | if (ENABLE_DESKTOP)
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234 | bb_error_msg_and_die("can't get groups");
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235 | return EXIT_FAILURE;
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236 | }
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237 | if (ENABLE_FEATURE_CLEAN_UP)
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238 | free(groups);
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239 | #if ENABLE_SELINUX
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240 | if (is_selinux_enabled()) {
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241 | if (getcon(&scontext) == 0)
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242 | printf(" context=%s", scontext);
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243 | }
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244 | #endif
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245 | } else if (opt & PRINT_REAL) {
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246 | euid = ruid;
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247 | egid = rgid;
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248 | }
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249 |
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250 | if (opt & JUST_USER)
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251 | status |= print_user(euid, NULL);
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252 | else if (opt & JUST_GROUP)
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253 | status |= print_group(egid, NULL);
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254 | #if ENABLE_SELINUX
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255 | else if (opt & JUST_CONTEXT) {
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256 | selinux_or_die();
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257 | if (username || getcon(&scontext)) {
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258 | bb_error_msg_and_die("can't get process context%s",
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259 | username ? " for a different user" : "");
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260 | }
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261 | fputs(scontext, stdout);
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262 | }
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263 | /* freecon(NULL) seems to be harmless */
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264 | if (ENABLE_FEATURE_CLEAN_UP)
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265 | freecon(scontext);
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266 | #endif
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267 | bb_putchar('\n');
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268 | fflush_stdout_and_exit(status);
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269 | }
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