| 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__) && UCLIBC_VERSION < KERNEL_VERSION(0, 9, 30)
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| 68 | #error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
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| 69 | #endif
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| 70 | #endif
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| 71 |
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| 72 | enum {
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| 73 | PRINT_REAL = (1 << 0),
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| 74 | NAME_NOT_NUMBER = (1 << 1),
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| 75 | JUST_USER = (1 << 2),
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| 76 | JUST_GROUP = (1 << 3),
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| 77 | JUST_ALL_GROUPS = (1 << 4),
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| 78 | #if ENABLE_SELINUX
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| 79 | JUST_CONTEXT = (1 << 5),
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| 80 | #endif
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| 81 | };
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| 82 |
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| 83 | static int print_common(unsigned id, const char *name, const char *prefix)
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| 84 | {
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| 85 | if (prefix) {
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| 86 | printf("%s", prefix);
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| 87 | }
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| 88 | if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
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| 89 | printf("%u", id);
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| 90 | }
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| 91 | if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
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| 92 | if (name) {
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| 93 | printf(option_mask32 ? "%s" : "(%s)", name);
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| 94 | } else {
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| 95 | /* Don't set error status flag in default mode */
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| 96 | if (option_mask32) {
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| 97 | if (ENABLE_DESKTOP)
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| 98 | bb_error_msg("unknown ID %u", id);
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| 99 | return EXIT_FAILURE;
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| 100 | }
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| 101 | }
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| 102 | }
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| 103 | return EXIT_SUCCESS;
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| 104 | }
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| 105 |
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| 106 | static int print_group(gid_t id, const char *prefix)
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| 107 | {
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| 108 | return print_common(id, gid2group(id), prefix);
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| 109 | }
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| 110 |
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| 111 | static int print_user(uid_t id, const char *prefix)
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| 112 | {
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| 113 | return print_common(id, uid2uname(id), prefix);
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| 114 | }
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| 115 |
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| 116 | /* On error set *n < 0 and return >= 0
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| 117 | * If *n is too small, update it and return < 0
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| 118 | * (ok to trash groups[] in both cases)
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| 119 | * Otherwise fill in groups[] and return >= 0
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| 120 | */
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| 121 | static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
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| 122 | {
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| 123 | int m;
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| 124 |
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| 125 | if (username) {
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| 126 | /* If the user is a member of more than
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| 127 | * *n groups, then -1 is returned. Otherwise >= 0.
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| 128 | * (and no defined way of detecting errors?!) */
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| 129 | m = getgrouplist(username, rgid, groups, n);
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| 130 | /* I guess *n < 0 might indicate error. Anyway,
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| 131 | * malloc'ing -1 bytes won't be good, so: */
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| 132 | if (*n < 0)
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| 133 | return 0;
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| 134 | return m;
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| 135 | }
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| 136 |
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| 137 | *n = getgroups(*n, groups);
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| 138 | if (*n >= 0)
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| 139 | return *n;
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| 140 | /* Error */
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| 141 | if (errno == EINVAL) /* *n is too small? */
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| 142 | *n = getgroups(0, groups); /* get needed *n */
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| 143 | /* if *n >= 0, return -1 (got new *n), else return 0 (error): */
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| 144 | return -(*n >= 0);
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| 145 | }
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| 146 |
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| 147 | int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 148 | int id_main(int argc UNUSED_PARAM, char **argv)
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| 149 | {
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| 150 | uid_t ruid;
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| 151 | gid_t rgid;
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| 152 | uid_t euid;
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| 153 | gid_t egid;
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| 154 | unsigned opt;
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| 155 | int i;
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| 156 | int status = EXIT_SUCCESS;
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| 157 | const char *prefix;
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| 158 | const char *username;
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| 159 | #if ENABLE_SELINUX
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| 160 | security_context_t scontext = NULL;
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| 161 | #endif
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| 162 |
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| 163 | if (ENABLE_GROUPS && (!ENABLE_ID || applet_name[0] == 'g')) {
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| 164 | /* TODO: coreutils groups prepend "USER : " prefix,
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| 165 | * and accept many usernames. Example:
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| 166 | * # groups root root
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| 167 | * root : root
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| 168 | * root : root
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| 169 | */
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| 170 | opt = option_mask32 = getopt32(argv, "") | JUST_ALL_GROUPS | NAME_NOT_NUMBER;
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| 171 | } else {
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| 172 | /* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
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| 173 | /* Don't allow more than one username */
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| 174 | opt_complementary = "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
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| 175 | IF_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G");
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| 176 | opt = getopt32(argv, "rnugG" IF_SELINUX("Z"));
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| 177 | }
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| 178 |
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| 179 | username = argv[optind];
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| 180 | if (username) {
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| 181 | struct passwd *p = xgetpwnam(username);
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| 182 | euid = ruid = p->pw_uid;
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| 183 | egid = rgid = p->pw_gid;
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| 184 | } else {
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| 185 | egid = getegid();
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| 186 | rgid = getgid();
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| 187 | euid = geteuid();
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| 188 | ruid = getuid();
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| 189 | }
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| 190 | /* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
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| 191 | /* id says: print the real ID instead of the effective ID, with -ugG */
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| 192 | /* in fact in this case egid is always printed if egid != rgid */
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| 193 | if (!opt || (opt & JUST_ALL_GROUPS)) {
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| 194 | gid_t *groups;
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| 195 | int n;
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| 196 |
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| 197 | if (!opt) {
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| 198 | /* Default Mode */
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| 199 | status |= print_user(ruid, "uid=");
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| 200 | status |= print_group(rgid, " gid=");
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| 201 | if (euid != ruid)
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| 202 | status |= print_user(euid, " euid=");
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| 203 | if (egid != rgid)
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| 204 | status |= print_group(egid, " egid=");
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| 205 | } else {
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| 206 | /* JUST_ALL_GROUPS */
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| 207 | status |= print_group(rgid, NULL);
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| 208 | if (egid != rgid)
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| 209 | status |= print_group(egid, " ");
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| 210 | }
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| 211 | /* We are supplying largish buffer, trying
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| 212 | * to not run get_groups() twice. That might be slow
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| 213 | * ("user database in remote SQL server" case) */
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| 214 | groups = xmalloc(64 * sizeof(groups[0]));
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| 215 | n = 64;
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| 216 | if (get_groups(username, rgid, groups, &n) < 0) {
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| 217 | /* Need bigger buffer after all */
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| 218 | groups = xrealloc(groups, n * sizeof(groups[0]));
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| 219 | get_groups(username, rgid, groups, &n);
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| 220 | }
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| 221 | if (n > 0) {
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| 222 | /* Print the list */
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| 223 | prefix = " groups=";
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| 224 | for (i = 0; i < n; i++) {
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| 225 | if (opt && (groups[i] == rgid || groups[i] == egid))
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| 226 | continue;
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| 227 | status |= print_group(groups[i], opt ? " " : prefix);
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| 228 | prefix = ",";
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| 229 | }
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| 230 | } else if (n < 0) { /* error in get_groups() */
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| 231 | if (ENABLE_DESKTOP)
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| 232 | bb_error_msg_and_die("can't get groups");
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| 233 | return EXIT_FAILURE;
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| 234 | }
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| 235 | if (ENABLE_FEATURE_CLEAN_UP)
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| 236 | free(groups);
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| 237 | #if ENABLE_SELINUX
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| 238 | if (is_selinux_enabled()) {
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| 239 | if (getcon(&scontext) == 0)
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| 240 | printf(" context=%s", scontext);
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| 241 | }
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| 242 | #endif
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| 243 | } else if (opt & PRINT_REAL) {
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| 244 | euid = ruid;
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| 245 | egid = rgid;
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| 246 | }
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| 247 |
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| 248 | if (opt & JUST_USER)
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| 249 | status |= print_user(euid, NULL);
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| 250 | else if (opt & JUST_GROUP)
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| 251 | status |= print_group(egid, NULL);
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| 252 | #if ENABLE_SELINUX
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| 253 | else if (opt & JUST_CONTEXT) {
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| 254 | selinux_or_die();
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| 255 | if (username || getcon(&scontext)) {
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| 256 | bb_error_msg_and_die("can't get process context%s",
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| 257 | username ? " for a different user" : "");
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| 258 | }
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| 259 | fputs(scontext, stdout);
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| 260 | }
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| 261 | /* freecon(NULL) seems to be harmless */
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| 262 | if (ENABLE_FEATURE_CLEAN_UP)
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| 263 | freecon(scontext);
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| 264 | #endif
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| 265 | bb_putchar('\n');
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| 266 | fflush_stdout_and_exit(status);
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| 267 | }
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