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 | #include "libbb.h"
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19 |
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20 | /* This is a NOEXEC applet. Be very careful! */
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21 |
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22 | #if !ENABLE_USE_BB_PWD_GRP
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23 | #if defined(__UCLIBC_MAJOR__) && (__UCLIBC_MAJOR__ == 0)
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24 | #if (__UCLIBC_MINOR__ < 9) || (__UCLIBC_MINOR__ == 9 && __UCLIBC_SUBLEVEL__ < 30)
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25 | #error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
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26 | #endif
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27 | #endif
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28 | #endif
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29 |
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30 | enum {
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31 | PRINT_REAL = (1 << 0),
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32 | NAME_NOT_NUMBER = (1 << 1),
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33 | JUST_USER = (1 << 2),
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34 | JUST_GROUP = (1 << 3),
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35 | JUST_ALL_GROUPS = (1 << 4),
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36 | #if ENABLE_SELINUX
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37 | JUST_CONTEXT = (1 << 5),
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38 | #endif
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39 | };
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40 |
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41 | static int print_common(unsigned id, const char *name, const char *prefix)
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42 | {
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43 | if (prefix) {
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44 | printf("%s", prefix);
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45 | }
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46 | if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
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47 | printf("%u", id);
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48 | }
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49 | if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
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50 | if (name) {
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51 | printf(option_mask32 ? "%s" : "(%s)", name);
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52 | } else {
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53 | /* Don't set error status flag in default mode */
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54 | if (option_mask32) {
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55 | if (ENABLE_DESKTOP)
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56 | bb_error_msg("unknown ID %u", id);
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57 | return EXIT_FAILURE;
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58 | }
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59 | }
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60 | }
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61 | return EXIT_SUCCESS;
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62 | }
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63 |
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64 | static int print_group(gid_t id, const char *prefix)
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65 | {
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66 | return print_common(id, gid2group(id), prefix);
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67 | }
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68 |
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69 | static int print_user(uid_t id, const char *prefix)
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70 | {
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71 | return print_common(id, uid2uname(id), prefix);
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72 | }
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73 |
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74 | /* On error set *n < 0 and return >= 0
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75 | * If *n is too small, update it and return < 0
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76 | * (ok to trash groups[] in both cases)
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77 | * Otherwise fill in groups[] and return >= 0
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78 | */
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79 | static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
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80 | {
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81 | int m;
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82 |
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83 | if (username) {
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84 | /* If the user is a member of more than
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85 | * *n groups, then -1 is returned. Otherwise >= 0.
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86 | * (and no defined way of detecting errors?!) */
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87 | m = getgrouplist(username, rgid, groups, n);
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88 | /* I guess *n < 0 might indicate error. Anyway,
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89 | * malloc'ing -1 bytes won't be good, so: */
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90 | //if (*n < 0)
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91 | // return 0;
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92 | //return m;
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93 | //commented out here, happens below anyway
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94 | } else {
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95 | /* On error -1 is returned, which ends up in *n */
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96 | int nn = getgroups(*n, groups);
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97 | /* 0: nn <= *n, groups[] was big enough; -1 otherwise */
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98 | m = - (nn > *n);
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99 | *n = nn;
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100 | }
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101 | if (*n < 0)
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102 | return 0; /* error, don't return < 0! */
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103 | return m;
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104 | }
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105 |
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106 | int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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107 | int id_main(int argc UNUSED_PARAM, char **argv)
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108 | {
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109 | uid_t ruid;
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110 | gid_t rgid;
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111 | uid_t euid;
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112 | gid_t egid;
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113 | unsigned opt;
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114 | int i;
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115 | int status = EXIT_SUCCESS;
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116 | const char *prefix;
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117 | const char *username;
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118 | #if ENABLE_SELINUX
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119 | security_context_t scontext = NULL;
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120 | #endif
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121 | /* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
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122 | /* Don't allow more than one username */
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123 | opt_complementary = "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
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124 | IF_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G");
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125 | opt = getopt32(argv, "rnugG" IF_SELINUX("Z"));
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126 |
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127 | username = argv[optind];
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128 | if (username) {
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129 | struct passwd *p = xgetpwnam(username);
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130 | euid = ruid = p->pw_uid;
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131 | egid = rgid = p->pw_gid;
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132 | } else {
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133 | egid = getegid();
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134 | rgid = getgid();
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135 | euid = geteuid();
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136 | ruid = getuid();
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137 | }
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138 | /* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
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139 | /* id says: print the real ID instead of the effective ID, with -ugG */
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140 | /* in fact in this case egid is always printed if egid != rgid */
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141 | if (!opt || (opt & JUST_ALL_GROUPS)) {
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142 | gid_t *groups;
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143 | int n;
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144 |
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145 | if (!opt) {
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146 | /* Default Mode */
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147 | status |= print_user(ruid, "uid=");
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148 | status |= print_group(rgid, " gid=");
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149 | if (euid != ruid)
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150 | status |= print_user(euid, " euid=");
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151 | if (egid != rgid)
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152 | status |= print_group(egid, " egid=");
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153 | } else {
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154 | /* JUST_ALL_GROUPS */
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155 | status |= print_group(rgid, NULL);
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156 | if (egid != rgid)
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157 | status |= print_group(egid, " ");
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158 | }
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159 | /* We are supplying largish buffer, trying
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160 | * to not run get_groups() twice. That might be slow
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161 | * ("user database in remote SQL server" case) */
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162 | groups = xmalloc(64 * sizeof(gid_t));
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163 | n = 64;
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164 | if (get_groups(username, rgid, groups, &n) < 0) {
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165 | /* Need bigger buffer after all */
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166 | groups = xrealloc(groups, n * sizeof(gid_t));
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167 | get_groups(username, rgid, groups, &n);
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168 | }
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169 | if (n > 0) {
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170 | /* Print the list */
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171 | prefix = " groups=";
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172 | for (i = 0; i < n; i++) {
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173 | if (opt && (groups[i] == rgid || groups[i] == egid))
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174 | continue;
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175 | status |= print_group(groups[i], opt ? " " : prefix);
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176 | prefix = ",";
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177 | }
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178 | } else if (n < 0) { /* error in get_groups() */
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179 | if (!ENABLE_DESKTOP)
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180 | bb_error_msg_and_die("can't get groups");
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181 | else
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182 | return EXIT_FAILURE;
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183 | }
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184 | if (ENABLE_FEATURE_CLEAN_UP)
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185 | free(groups);
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186 | #if ENABLE_SELINUX
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187 | if (is_selinux_enabled()) {
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188 | if (getcon(&scontext) == 0)
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189 | printf(" context=%s", scontext);
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190 | }
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191 | #endif
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192 | } else if (opt & PRINT_REAL) {
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193 | euid = ruid;
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194 | egid = rgid;
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195 | }
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196 |
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197 | if (opt & JUST_USER)
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198 | status |= print_user(euid, NULL);
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199 | else if (opt & JUST_GROUP)
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200 | status |= print_group(egid, NULL);
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201 | #if ENABLE_SELINUX
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202 | else if (opt & JUST_CONTEXT) {
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203 | selinux_or_die();
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204 | if (username || getcon(&scontext)) {
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205 | bb_error_msg_and_die("can't get process context%s",
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206 | username ? " for a different user" : "");
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207 | }
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208 | fputs(scontext, stdout);
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209 | }
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210 | /* freecon(NULL) seems to be harmless */
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211 | if (ENABLE_FEATURE_CLEAN_UP)
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212 | freecon(scontext);
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213 | #endif
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214 | bb_putchar('\n');
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215 | fflush_stdout_and_exit(status);
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216 | }
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