summaryrefslogtreecommitdiff
path: root/loginutils/addgroup.c
blob: b29b66527bd906dfa35ced6e61c57df6dae52b5a (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
/* vi: set sw=4 ts=4: */
/*
 * addgroup - add groups to /etc/group and /etc/gshadow
 *
 * Copyright (C) 1999 by Lineo, inc. and John Beppu
 * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
 * Copyright (C) 2007 by Tito Ragusa <farmatito@tiscali.it>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 */

#include "libbb.h"

static void xgroup_study(struct group *g)
{
	enum { max = 65000 };
	/* Use a particular gid. */
	int desired = (g->gr_gid > 0);

	/* Make sure gr_name is unused */
	if (getgrnam(g->gr_name)) {
		goto error;
	}

	/* Check if the desired gid is free or
	   find the first free one */
	do {
		if (g->gr_gid == max) { /* out of bounds: exit */
			bb_error_msg_and_die("no gids left");
		}
		if (!getgrgid(g->gr_gid)) {
			return; /* ok */
		}
		if (desired) { /* the desired gid is already in use: exit */
			g->gr_name = itoa(g->gr_gid);
			goto error;
		}
		g->gr_gid++;
	} while (1);

error:
	/* exit */
	bb_error_msg_and_die("%s: already in use", g->gr_name);
}

/* append a new user to the passwd file */
static void new_group(char *group, gid_t gid)
{
	FILE *file;
	struct group gr;

	/* make sure gid and group haven't already been allocated */
	gr.gr_gid = gid;
	gr.gr_name = group;
	xgroup_study( &gr);

	/* add entry to group */
	file = xfopen(bb_path_group_file, "a");
	/* group:passwd:gid:userlist */
	fprintf(file, "%s:x:%d:\n", group, gr.gr_gid);
	if (ENABLE_FEATURE_CLEAN_UP)
		fclose(file);
#if ENABLE_FEATURE_SHADOWPASSWDS
	file = fopen_or_warn(bb_path_gshadow_file, "a");
	if (file) {
		fprintf(file, "%s:!::\n", group);
		if (ENABLE_FEATURE_CLEAN_UP)
			fclose(file);
	}
#endif
}

#if ENABLE_FEATURE_ADDUSER_TO_GROUP
static void add_user_to_group(char **args,
		const char *path,
		FILE *(*fopen_func)(const char *fileName, const char *mode))
{
	char *line;
	int len = strlen(args[1]);
	llist_t *plist = NULL;
	FILE *group_file;

	group_file = fopen_func(path, "r");

	if (!group_file) return;

	while ((line = xmalloc_getline(group_file))) {
		/* Find the group */
		if (!strncmp(line, args[1], len)
		&& line[len] == ':'
		) {
			/* Add the new user */
			line = xasprintf("%s%s%s", line,
						last_char_is(line, ':') ? "" : ",",
						args[0]);
		}
		llist_add_to_end(&plist, line);
	}

	if (ENABLE_FEATURE_CLEAN_UP) {
		fclose(group_file);
		group_file = fopen_func(path, "w");
		while ((line = llist_pop(&plist))) {
			if (group_file)
				fprintf(group_file, "%s\n", line);
			free(line);
		}
		if (group_file)
			fclose(group_file);
	} else {
		group_file = fopen_func(path, "w");
		if (group_file)
			while ((line = llist_pop(&plist)))
				fprintf(group_file, "%s\n", line);
	}
}
#endif

/*
 * addgroup will take a login_name as its first parameter.
 *
 * gid can be customized via command-line parameters.
 * If  called with two non-option arguments, addgroup
 * will add an existing user to an existing group.
 */
int addgroup_main(int argc, char **argv);
int addgroup_main(int argc, char **argv)
{
	char *group;
	gid_t gid = 0;

	/* check for min, max and missing args and exit on error */
	opt_complementary = "-1:?2:?";
	if (getopt32(argc, argv, "g:", &group)) {
		gid = xatoul_range(group, 0, (gid_t)ULONG_MAX);
	}
	/* move past the commandline options */
	argv += optind;
	argc -= optind;

	/* need to be root */
	if (geteuid()) {
		bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
	}

#if ENABLE_FEATURE_ADDUSER_TO_GROUP
	if (argc == 2) {
		struct group *gr;

		/* check if group and user exist */
		xuname2uid(argv[0]); /* unknown user: exit */
		xgroup2gid(argv[1]); /* unknown group: exit */
		/* check if user is already in this group */
		gr = getgrnam(argv[1]);
		for (; *(gr->gr_mem) != NULL; (gr->gr_mem)++) {
			if (!strcmp(argv[0], *(gr->gr_mem))) {
				/* user is already in group: do nothing */
				return EXIT_SUCCESS;
			}
		}
		add_user_to_group(argv, bb_path_group_file, xfopen);
#if ENABLE_FEATURE_SHADOWPASSWDS
		add_user_to_group(argv, bb_path_gshadow_file, fopen_or_warn);
#endif /* ENABLE_FEATURE_SHADOWPASSWDS */
	} else
#endif /* ENABLE_FEATURE_ADDUSER_TO_GROUP */
		new_group(argv[0], gid);

	/* Reached only on success */
	return EXIT_SUCCESS;
}