summaryrefslogtreecommitdiff
path: root/coreutils/id.c (plain)
blob: ab7ac1e559b1b188ca0b77f950b7930c2e2a54a4
1/* vi: set sw=4 ts=4: */
2/*
3 * Mini id implementation for busybox
4 *
5 * Copyright (C) 2000 by Randolph Chung <tausq@debian.org>
6 * Copyright (C) 2008 by Tito Ragusa <farmatito@tiscali.it>
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 */
10/* Hacked by Tito Ragusa (C) 2004 to handle usernames of whatever
11 * length and to be more similar to GNU id.
12 * -Z option support: by Yuichi Nakamura <ynakam@hitachisoft.jp>
13 * Added -G option Tito Ragusa (C) 2008 for SUSv3.
14 */
15//config:config ID
16//config: bool "id"
17//config: default y
18//config: help
19//config: id displays the current user and group ID names.
20//config:
21//config:config GROUPS
22//config: bool "groups"
23//config: default y
24//config: help
25//config: Print the group names associated with current user id.
26
27//applet:IF_GROUPS(APPLET_NOEXEC(groups, id, BB_DIR_USR_BIN, BB_SUID_DROP, groups))
28//applet:IF_ID( APPLET_NOEXEC(id, id, BB_DIR_USR_BIN, BB_SUID_DROP, id ))
29
30//kbuild:lib-$(CONFIG_GROUPS) += id.o
31//kbuild:lib-$(CONFIG_ID) += id.o
32
33/* BB_AUDIT SUSv3 compliant. */
34
35//usage:#define id_trivial_usage
36//usage: "[OPTIONS] [USER]"
37//usage:#define id_full_usage "\n\n"
38//usage: "Print information about USER or the current user\n"
39//usage: IF_SELINUX(
40//usage: "\n -Z Security context"
41//usage: )
42//usage: "\n -u User ID"
43//usage: "\n -g Group ID"
44//usage: "\n -G Supplementary group IDs"
45//usage: "\n -n Print names instead of numbers"
46//usage: "\n -r Print real ID instead of effective ID"
47//usage:
48//usage:#define id_example_usage
49//usage: "$ id\n"
50//usage: "uid=1000(andersen) gid=1000(andersen)\n"
51
52//usage:#define groups_trivial_usage
53//usage: "[USER]"
54//usage:#define groups_full_usage "\n\n"
55//usage: "Print the group memberships of USER or for the current process"
56//usage:
57//usage:#define groups_example_usage
58//usage: "$ groups\n"
59//usage: "andersen lp dialout cdrom floppy\n"
60
61#include "libbb.h"
62
63/* This is a NOEXEC applet. Be very careful! */
64
65#if !ENABLE_USE_BB_PWD_GRP
66#if defined(__UCLIBC__) && UCLIBC_VERSION < KERNEL_VERSION(0, 9, 30)
67#error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
68#endif
69#endif
70
71enum {
72 PRINT_REAL = (1 << 0),
73 NAME_NOT_NUMBER = (1 << 1),
74 JUST_USER = (1 << 2),
75 JUST_GROUP = (1 << 3),
76 JUST_ALL_GROUPS = (1 << 4),
77#if ENABLE_SELINUX
78 JUST_CONTEXT = (1 << 5),
79#endif
80};
81
82static int print_common(unsigned id, const char *name, const char *prefix)
83{
84 if (prefix) {
85 printf("%s", prefix);
86 }
87 if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
88 printf("%u", id);
89 }
90 if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
91 if (name) {
92 printf(option_mask32 ? "%s" : "(%s)", name);
93 } else {
94 /* Don't set error status flag in default mode */
95 if (option_mask32) {
96 if (ENABLE_DESKTOP)
97 bb_error_msg("unknown ID %u", id);
98 return EXIT_FAILURE;
99 }
100 }
101 }
102 return EXIT_SUCCESS;
103}
104
105static int print_group(gid_t id, const char *prefix)
106{
107 return print_common(id, gid2group(id), prefix);
108}
109
110static int print_user(uid_t id, const char *prefix)
111{
112 return print_common(id, uid2uname(id), prefix);
113}
114
115/* On error set *n < 0 and return >= 0
116 * If *n is too small, update it and return < 0
117 * (ok to trash groups[] in both cases)
118 * Otherwise fill in groups[] and return >= 0
119 */
120static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
121{
122 int m;
123
124 if (username) {
125 /* If the user is a member of more than
126 * *n groups, then -1 is returned. Otherwise >= 0.
127 * (and no defined way of detecting errors?!) */
128 m = getgrouplist(username, rgid, groups, n);
129 /* I guess *n < 0 might indicate error. Anyway,
130 * malloc'ing -1 bytes won't be good, so: */
131 if (*n < 0)
132 return 0;
133 return m;
134 }
135
136 *n = getgroups(*n, groups);
137 if (*n >= 0)
138 return *n;
139 /* Error */
140 if (errno == EINVAL) /* *n is too small? */
141 *n = getgroups(0, groups); /* get needed *n */
142 /* if *n >= 0, return -1 (got new *n), else return 0 (error): */
143 return -(*n >= 0);
144}
145
146int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
147int id_main(int argc UNUSED_PARAM, char **argv)
148{
149 uid_t ruid;
150 gid_t rgid;
151 uid_t euid;
152 gid_t egid;
153 unsigned opt;
154 int i;
155 int status = EXIT_SUCCESS;
156 const char *prefix;
157 const char *username;
158#if ENABLE_SELINUX
159 security_context_t scontext = NULL;
160#endif
161
162 if (ENABLE_GROUPS && (!ENABLE_ID || applet_name[0] == 'g')) {
163 /* TODO: coreutils groups prepend "USER : " prefix,
164 * and accept many usernames. Example:
165 * # groups root root
166 * root : root
167 * root : root
168 */
169 opt = option_mask32 = getopt32(argv, "") | JUST_ALL_GROUPS | NAME_NOT_NUMBER;
170 } else {
171 /* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
172 /* Don't allow more than one username */
173 opt_complementary = "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
174 IF_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G");
175 opt = getopt32(argv, "rnugG" IF_SELINUX("Z"));
176 }
177
178 username = argv[optind];
179 if (username) {
180 struct passwd *p = xgetpwnam(username);
181 euid = ruid = p->pw_uid;
182 egid = rgid = p->pw_gid;
183 } else {
184 egid = getegid();
185 rgid = getgid();
186 euid = geteuid();
187 ruid = getuid();
188 }
189 /* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
190 /* id says: print the real ID instead of the effective ID, with -ugG */
191 /* in fact in this case egid is always printed if egid != rgid */
192 if (!opt || (opt & JUST_ALL_GROUPS)) {
193 gid_t *groups;
194 int n;
195
196 if (!opt) {
197 /* Default Mode */
198 status |= print_user(ruid, "uid=");
199 status |= print_group(rgid, " gid=");
200 if (euid != ruid)
201 status |= print_user(euid, " euid=");
202 if (egid != rgid)
203 status |= print_group(egid, " egid=");
204 } else {
205 /* JUST_ALL_GROUPS */
206 status |= print_group(rgid, NULL);
207 if (egid != rgid)
208 status |= print_group(egid, " ");
209 }
210 /* We are supplying largish buffer, trying
211 * to not run get_groups() twice. That might be slow
212 * ("user database in remote SQL server" case) */
213 groups = xmalloc(64 * sizeof(groups[0]));
214 n = 64;
215 if (get_groups(username, rgid, groups, &n) < 0) {
216 /* Need bigger buffer after all */
217 groups = xrealloc(groups, n * sizeof(groups[0]));
218 get_groups(username, rgid, groups, &n);
219 }
220 if (n > 0) {
221 /* Print the list */
222 prefix = " groups=";
223 for (i = 0; i < n; i++) {
224 if (opt && (groups[i] == rgid || groups[i] == egid))
225 continue;
226 status |= print_group(groups[i], opt ? " " : prefix);
227 prefix = ",";
228 }
229 } else if (n < 0) { /* error in get_groups() */
230 if (ENABLE_DESKTOP)
231 bb_error_msg_and_die("can't get groups");
232 return EXIT_FAILURE;
233 }
234 if (ENABLE_FEATURE_CLEAN_UP)
235 free(groups);
236#if ENABLE_SELINUX
237 if (is_selinux_enabled()) {
238 if (getcon(&scontext) == 0)
239 printf(" context=%s", scontext);
240 }
241#endif
242 } else if (opt & PRINT_REAL) {
243 euid = ruid;
244 egid = rgid;
245 }
246
247 if (opt & JUST_USER)
248 status |= print_user(euid, NULL);
249 else if (opt & JUST_GROUP)
250 status |= print_group(egid, NULL);
251#if ENABLE_SELINUX
252 else if (opt & JUST_CONTEXT) {
253 selinux_or_die();
254 if (username || getcon(&scontext)) {
255 bb_error_msg_and_die("can't get process context%s",
256 username ? " for a different user" : "");
257 }
258 fputs(scontext, stdout);
259 }
260 /* freecon(NULL) seems to be harmless */
261 if (ENABLE_FEATURE_CLEAN_UP)
262 freecon(scontext);
263#endif
264 bb_putchar('\n');
265 fflush_stdout_and_exit(status);
266}
267
generated by cgit at 2024-05-15 14:45:08 (GMT)