1 /* vi: set sw=4 ts=4: */
3 * Mini id implementation for busybox
5 * Copyright (C) 2000 by Randolph Chung <tausq@debian.org>
6 * Copyright (C) 2008 by Tito Ragusa <farmatito@tiscali.it>
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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.
16 //config: bool "id (6.7 kb)"
19 //config: id displays the current user and group ID names.
21 //config:config GROUPS
22 //config: bool "groups (6.5 kb)"
25 //config: Print the group names associated with current user id.
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 ))
30 //kbuild:lib-$(CONFIG_GROUPS) += id.o
31 //kbuild:lib-$(CONFIG_ID) += id.o
33 /* BB_AUDIT SUSv3 compliant. */
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"
40 //usage: "\n -Z Security context"
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"
48 //usage:#define id_example_usage
50 //usage: "uid=1000(andersen) gid=1000(andersen)\n"
52 //usage:#define groups_trivial_usage
54 //usage:#define groups_full_usage "\n\n"
55 //usage: "Print the group memberships of USER or for the current process"
57 //usage:#define groups_example_usage
59 //usage: "andersen lp dialout cdrom floppy\n"
63 /* This is a NOEXEC applet. Be very careful! */
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"
72 PRINT_REAL = (1 << 0),
73 NAME_NOT_NUMBER = (1 << 1),
75 JUST_GROUP = (1 << 3),
76 JUST_ALL_GROUPS = (1 << 4),
78 JUST_CONTEXT = (1 << 5),
82 static int print_common(unsigned id, const char *name, const char *prefix)
87 if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
90 if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
92 printf(option_mask32 ? "%s" : "(%s)", name);
94 /* Don't set error status flag in default mode */
97 bb_error_msg("unknown ID %u", id);
105 static int print_group(gid_t id, const char *prefix)
107 return print_common(id, gid2group(id), prefix);
110 static int print_user(uid_t id, const char *prefix)
112 return print_common(id, uid2uname(id), prefix);
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
120 static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
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: */
136 *n = getgroups(*n, groups);
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): */
146 int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
147 int id_main(int argc UNUSED_PARAM, char **argv)
155 int status = EXIT_SUCCESS;
157 const char *username;
159 security_context_t scontext = NULL;
162 if (ENABLE_GROUPS && (!ENABLE_ID || applet_name[0] == 'g')) {
163 /* TODO: coreutils groups prepend "USER : " prefix,
164 * and accept many usernames. Example:
169 opt = option_mask32 = getopt32(argv, "") | JUST_ALL_GROUPS | NAME_NOT_NUMBER;
171 /* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
172 /* Don't allow more than one username */
173 opt = getopt32(argv, "^"
174 "rnugG" IF_SELINUX("Z")
176 "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
177 IF_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G")
181 username = argv[optind];
183 struct passwd *p = xgetpwnam(username);
184 euid = ruid = p->pw_uid;
185 egid = rgid = p->pw_gid;
192 /* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
193 /* id says: print the real ID instead of the effective ID, with -ugG */
194 /* in fact in this case egid is always printed if egid != rgid */
195 if (!opt || (opt & JUST_ALL_GROUPS)) {
201 status |= print_user(ruid, "uid=");
202 status |= print_group(rgid, " gid=");
204 status |= print_user(euid, " euid=");
206 status |= print_group(egid, " egid=");
208 /* JUST_ALL_GROUPS */
209 status |= print_group(rgid, NULL);
211 status |= print_group(egid, " ");
213 /* We are supplying largish buffer, trying
214 * to not run get_groups() twice. That might be slow
215 * ("user database in remote SQL server" case) */
216 groups = xmalloc(64 * sizeof(groups[0]));
218 if (get_groups(username, rgid, groups, &n) < 0) {
219 /* Need bigger buffer after all */
220 groups = xrealloc(groups, n * sizeof(groups[0]));
221 get_groups(username, rgid, groups, &n);
226 for (i = 0; i < n; i++) {
227 if (opt && (groups[i] == rgid || groups[i] == egid))
229 status |= print_group(groups[i], opt ? " " : prefix);
232 } else if (n < 0) { /* error in get_groups() */
234 bb_error_msg_and_die("can't get groups");
237 if (ENABLE_FEATURE_CLEAN_UP)
240 if (is_selinux_enabled()) {
241 if (getcon(&scontext) == 0)
242 printf(" context=%s", scontext);
245 } else if (opt & PRINT_REAL) {
251 status |= print_user(euid, NULL);
252 else if (opt & JUST_GROUP)
253 status |= print_group(egid, NULL);
255 else if (opt & JUST_CONTEXT) {
257 if (username || getcon(&scontext)) {
258 bb_error_msg_and_die("can't get process context%s",
259 username ? " for a different user" : "");
261 fputs(scontext, stdout);
263 /* freecon(NULL) seems to be harmless */
264 if (ENABLE_FEATURE_CLEAN_UP)
268 fflush_stdout_and_exit(status);