summaryrefslogtreecommitdiffhomepage
path: root/coreutils/id.c
blob: 6ddb2366646e19fa7cdafd773cc821b608bde35e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
/* vi: set sw=4 ts=4: */
/*
 * Mini id implementation for busybox
 *
 * Copyright (C) 2000 by Randolph Chung <tausq@debian.org>
 * Copyright (C) 2008 by Tito Ragusa <farmatito@tiscali.it>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* BB_AUDIT SUSv3 compliant. */
/* Hacked by Tito Ragusa (C) 2004 to handle usernames of whatever
 * length and to be more similar to GNU id.
 * -Z option support: by Yuichi Nakamura <ynakam@hitachisoft.jp>
 * Added -G option Tito Ragusa (C) 2008 for SUSv3.
 */

#include "libbb.h"

#if !ENABLE_USE_BB_PWD_GRP
#if defined(__UCLIBC_MAJOR__) && (__UCLIBC_MAJOR__ == 0)
#if (__UCLIBC_MINOR__ < 9) || (__UCLIBC_MINOR__ == 9 &&  __UCLIBC_SUBLEVEL__ < 30)
#error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
#endif
#endif
#endif

enum {
	PRINT_REAL      = (1 << 0),
	NAME_NOT_NUMBER = (1 << 1),
	JUST_USER       = (1 << 2),
	JUST_GROUP      = (1 << 3),
	JUST_ALL_GROUPS = (1 << 4),
#if ENABLE_SELINUX
	JUST_CONTEXT    = (1 << 5),
#endif
};

static int print_common(unsigned id,
		char* FAST_FUNC bb_getXXXid(char *name, int bufsize, long uid),
		const char *prefix)
{
	const char *name = bb_getXXXid(NULL, 0, id);

	if (prefix) {
		printf("%s", prefix);
	}
	if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
		printf("%u", id);
	}
	if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
		if (name) {
			printf(option_mask32 ? "%s" : "(%s)", name);
		} else {
			/* Don't set error status flag in default mode */
			if (option_mask32) {
				if (ENABLE_DESKTOP)
					bb_error_msg("unknown ID %u", id);
				return EXIT_FAILURE;
			}
		}
	}
	return EXIT_SUCCESS;
}

static int print_group(gid_t id, const char *prefix)
{
	return print_common(id, bb_getgrgid, prefix);
}

static int print_user(uid_t id, const char *prefix)
{
	return print_common(id, bb_getpwuid, prefix);
}

/* On error set *n < 0 and return >= 0
 * If *n is too small, update it and return < 0
 *  (ok to trash groups[] in both cases)
 * Otherwise fill in groups[] and return >= 0
 */
static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
{
	int m;

	if (username) {
		/* If the user is a member of more than
		 * *n groups, then -1 is returned. Otherwise >= 0.
		 * (and no defined way of detecting errors?!) */
		m = getgrouplist(username, rgid, groups, n);
		/* I guess *n < 0 might indicate error. Anyway,
		 * malloc'ing -1 bytes won't be good, so: */
		//if (*n < 0)
		//	return 0;
		//return m;
		//commented out here, happens below anyway
	} else {
		/* On error -1 is returned, which ends up in *n */
		int nn = getgroups(*n, groups);
		/* 0: nn <= *n, groups[] was big enough; -1 otherwise */
		m = - (nn > *n);
		*n = nn;
	}
	if (*n < 0)
		return 0; /* error, don't return < 0! */
	return m;
}

int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int id_main(int argc UNUSED_PARAM, char **argv)
{
	uid_t ruid;
	gid_t rgid;
	uid_t euid;
	gid_t egid;
	unsigned opt;
	int i;
	int status = EXIT_SUCCESS;
	const char *prefix;
	const char *username;
#if ENABLE_SELINUX
	security_context_t scontext = NULL;
#endif
	/* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
	/* Don't allow more than one username */
	opt_complementary = "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
			 USE_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G");
	opt = getopt32(argv, "rnugG" USE_SELINUX("Z"));

	username = argv[optind];
	if (username) {
		struct passwd *p = getpwnam(username);
		if (!p)
			bb_error_msg_and_die("unknown user %s", username);
		euid = ruid = p->pw_uid;
		egid = rgid = p->pw_gid;
	} else {
		egid = getegid();
		rgid = getgid();
		euid = geteuid();
		ruid = getuid();
	}
	/* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
	/* id says: print the real ID instead of the effective ID, with -ugG */
	/* in fact in this case egid is always printed if egid != rgid */
	if (!opt || (opt & JUST_ALL_GROUPS)) {
		gid_t *groups;
		int n;

		if (!opt) {
			/* Default Mode */
			status |= print_user(ruid, "uid=");
			status |= print_group(rgid, " gid=");
			if (euid != ruid)
				status |= print_user(euid, " euid=");
			if (egid != rgid)
				status |= print_group(egid, " egid=");
		} else {
			/* JUST_ALL_GROUPS */
			status |= print_group(rgid, NULL);
			if (egid != rgid)
				status |= print_group(egid, " ");
		}
		/* We are supplying largish buffer, trying
		 * to not run get_groups() twice. That might be slow
		 * ("user database in remote SQL server" case) */
		groups = xmalloc(64 * sizeof(gid_t));
		n = 64;
		if (get_groups(username, rgid, groups, &n) < 0) {
			/* Need bigger buffer after all */
			groups = xrealloc(groups, n * sizeof(gid_t));
			get_groups(username, rgid, groups, &n);
		}
		if (n > 0) {
			/* Print the list */
			prefix = " groups=";
			for (i = 0; i < n; i++) {
				if (opt && (groups[i] == rgid || groups[i] == egid))
					continue;
				status |= print_group(groups[i], opt ? " " : prefix);
				prefix = ",";
			}
		} else if (n < 0) { /* error in get_groups() */
			if (!ENABLE_DESKTOP)
				bb_error_msg_and_die("cannot get groups");
			else
				return EXIT_FAILURE;
		}
		if (ENABLE_FEATURE_CLEAN_UP)
			free(groups);
#if ENABLE_SELINUX
		if (is_selinux_enabled()) {
			if (getcon(&scontext) == 0)
				printf(" context=%s", scontext);
		}
#endif
	} else if (opt & PRINT_REAL) {
		euid = ruid;
		egid = rgid;
	}

	if (opt & JUST_USER)
		status |= print_user(euid, NULL);
	else if (opt & JUST_GROUP)
		status |= print_group(egid, NULL);
#if ENABLE_SELINUX
	else if (opt & JUST_CONTEXT) {
		selinux_or_die();
		if (username || getcon(&scontext)) {
			bb_error_msg_and_die("can't get process context%s",
				username ? " for a different user" : "");
		}
		fputs(scontext, stdout);
	}
	/* freecon(NULL) seems to be harmless */
	if (ENABLE_FEATURE_CLEAN_UP)
		freecon(scontext);
#endif
	bb_putchar('\n');
	fflush_stdout_and_exit(status);
}