source: branches/3.2/mindi-busybox/coreutils/id.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 7.3 KB
Line 
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
11/* BB_AUDIT SUSv3 compliant. */
12/* Hacked by Tito Ragusa (C) 2004 to handle usernames of whatever
13 * length and to be more similar to GNU id.
14 * -Z option support: by Yuichi Nakamura <ynakam@hitachisoft.jp>
15 * Added -G option Tito Ragusa (C) 2008 for SUSv3.
16 */
17
18//config:config ID
19//config:   bool "id"
20//config:   default y
21//config:   help
22//config:     id displays the current user and group ID names.
23
24//config:config GROUPS
25//config:   bool "groups"
26//config:   default y
27//config:   help
28//config:     Print the group names associated with current user id.
29
30//kbuild:lib-$(CONFIG_GROUPS) += id.o
31//kbuild:lib-$(CONFIG_ID)     += id.o
32
33//applet:IF_GROUPS(APPLET_NOEXEC(groups, id, BB_DIR_USR_BIN, BB_SUID_DROP, groups))
34//applet:IF_ID(    APPLET_NOEXEC(id,     id, BB_DIR_USR_BIN, BB_SUID_DROP, id    ))
35
36//usage:#define id_trivial_usage
37//usage:       "[OPTIONS] [USER]"
38//usage:#define id_full_usage "\n\n"
39//usage:       "Print information about USER or the current user\n"
40//usage:    IF_SELINUX(
41//usage:     "\n    -Z  Security context"
42//usage:    )
43//usage:     "\n    -u  User ID"
44//usage:     "\n    -g  Group ID"
45//usage:     "\n    -G  Supplementary group IDs"
46//usage:     "\n    -n  Print names instead of numbers"
47//usage:     "\n    -r  Print real ID instead of effective ID"
48//usage:
49//usage:#define id_example_usage
50//usage:       "$ id\n"
51//usage:       "uid=1000(andersen) gid=1000(andersen)\n"
52
53//usage:#define groups_trivial_usage
54//usage:       "[USER]"
55//usage:#define groups_full_usage "\n\n"
56//usage:       "Print the group memberships of USER or for the current process"
57//usage:
58//usage:#define groups_example_usage
59//usage:       "$ groups\n"
60//usage:       "andersen lp dialout cdrom floppy\n"
61
62#include "libbb.h"
63
64/* This is a NOEXEC applet. Be very careful! */
65
66#if !ENABLE_USE_BB_PWD_GRP
67#if defined(__UCLIBC_MAJOR__) && (__UCLIBC_MAJOR__ == 0)
68#if (__UCLIBC_MINOR__ < 9) || (__UCLIBC_MINOR__ == 9 &&  __UCLIBC_SUBLEVEL__ < 30)
69#error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
70#endif
71#endif
72#endif
73
74enum {
75    PRINT_REAL      = (1 << 0),
76    NAME_NOT_NUMBER = (1 << 1),
77    JUST_USER       = (1 << 2),
78    JUST_GROUP      = (1 << 3),
79    JUST_ALL_GROUPS = (1 << 4),
80#if ENABLE_SELINUX
81    JUST_CONTEXT    = (1 << 5),
82#endif
83};
84
85static int print_common(unsigned id, const char *name, const char *prefix)
86{
87    if (prefix) {
88        printf("%s", prefix);
89    }
90    if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
91        printf("%u", id);
92    }
93    if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
94        if (name) {
95            printf(option_mask32 ? "%s" : "(%s)", name);
96        } else {
97            /* Don't set error status flag in default mode */
98            if (option_mask32) {
99                if (ENABLE_DESKTOP)
100                    bb_error_msg("unknown ID %u", id);
101                return EXIT_FAILURE;
102            }
103        }
104    }
105    return EXIT_SUCCESS;
106}
107
108static int print_group(gid_t id, const char *prefix)
109{
110    return print_common(id, gid2group(id), prefix);
111}
112
113static int print_user(uid_t id, const char *prefix)
114{
115    return print_common(id, uid2uname(id), prefix);
116}
117
118/* On error set *n < 0 and return >= 0
119 * If *n is too small, update it and return < 0
120 * (ok to trash groups[] in both cases)
121 * Otherwise fill in groups[] and return >= 0
122 */
123static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
124{
125    int m;
126
127    if (username) {
128        /* If the user is a member of more than
129         * *n groups, then -1 is returned. Otherwise >= 0.
130         * (and no defined way of detecting errors?!) */
131        m = getgrouplist(username, rgid, groups, n);
132        /* I guess *n < 0 might indicate error. Anyway,
133         * malloc'ing -1 bytes won't be good, so: */
134        if (*n < 0)
135            return 0;
136        return m;
137    }
138
139    *n = getgroups(*n, groups);
140    if (*n >= 0)
141        return *n;
142    /* Error */
143    if (errno == EINVAL) /* *n is too small? */
144        *n = getgroups(0, groups); /* get needed *n */
145    /* if *n >= 0, return -1 (got new *n), else return 0 (error): */
146    return -(*n >= 0);
147}
148
149int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
150int id_main(int argc UNUSED_PARAM, char **argv)
151{
152    uid_t ruid;
153    gid_t rgid;
154    uid_t euid;
155    gid_t egid;
156    unsigned opt;
157    int i;
158    int status = EXIT_SUCCESS;
159    const char *prefix;
160    const char *username;
161#if ENABLE_SELINUX
162    security_context_t scontext = NULL;
163#endif
164
165    if (ENABLE_GROUPS && (!ENABLE_ID || applet_name[0] == 'g')) {
166        /* TODO: coreutils groups prepend "USER : " prefix,
167         * and accept many usernames. Example:
168         * # groups root root
169         * root : root
170         * root : root
171         */
172        opt = option_mask32 = getopt32(argv, "") | JUST_ALL_GROUPS | NAME_NOT_NUMBER;
173    } else {
174        /* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
175        /* Don't allow more than one username */
176        opt_complementary = "?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");
178        opt = getopt32(argv, "rnugG" IF_SELINUX("Z"));
179    }
180
181    username = argv[optind];
182    if (username) {
183        struct passwd *p = xgetpwnam(username);
184        euid = ruid = p->pw_uid;
185        egid = rgid = p->pw_gid;
186    } else {
187        egid = getegid();
188        rgid = getgid();
189        euid = geteuid();
190        ruid = getuid();
191    }
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)) {
196        gid_t *groups;
197        int n;
198
199        if (!opt) {
200            /* Default Mode */
201            status |= print_user(ruid, "uid=");
202            status |= print_group(rgid, " gid=");
203            if (euid != ruid)
204                status |= print_user(euid, " euid=");
205            if (egid != rgid)
206                status |= print_group(egid, " egid=");
207        } else {
208            /* JUST_ALL_GROUPS */
209            status |= print_group(rgid, NULL);
210            if (egid != rgid)
211                status |= print_group(egid, " ");
212        }
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]));
217        n = 64;
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);
222        }
223        if (n > 0) {
224            /* Print the list */
225            prefix = " groups=";
226            for (i = 0; i < n; i++) {
227                if (opt && (groups[i] == rgid || groups[i] == egid))
228                    continue;
229                status |= print_group(groups[i], opt ? " " : prefix);
230                prefix = ",";
231            }
232        } else if (n < 0) { /* error in get_groups() */
233            if (ENABLE_DESKTOP)
234                bb_error_msg_and_die("can't get groups");
235            return EXIT_FAILURE;
236        }
237        if (ENABLE_FEATURE_CLEAN_UP)
238            free(groups);
239#if ENABLE_SELINUX
240        if (is_selinux_enabled()) {
241            if (getcon(&scontext) == 0)
242                printf(" context=%s", scontext);
243        }
244#endif
245    } else if (opt & PRINT_REAL) {
246        euid = ruid;
247        egid = rgid;
248    }
249
250    if (opt & JUST_USER)
251        status |= print_user(euid, NULL);
252    else if (opt & JUST_GROUP)
253        status |= print_group(egid, NULL);
254#if ENABLE_SELINUX
255    else if (opt & JUST_CONTEXT) {
256        selinux_or_die();
257        if (username || getcon(&scontext)) {
258            bb_error_msg_and_die("can't get process context%s",
259                username ? " for a different user" : "");
260        }
261        fputs(scontext, stdout);
262    }
263    /* freecon(NULL) seems to be harmless */
264    if (ENABLE_FEATURE_CLEAN_UP)
265        freecon(scontext);
266#endif
267    bb_putchar('\n');
268    fflush_stdout_and_exit(status);
269}
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