1 /* groups -- print the groups a user is in
2 Copyright (C) 1989-2023 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 /* Written by James Youngman based on id.c and groups.sh,
18 which were written by Arnold Robbins and David MacKenzie. */
19
20 #include <config.h>
21 #include <stdio.h>
22 #include <sys/types.h>
23 #include <pwd.h>
24 #include <grp.h>
25 #include <getopt.h>
26
27 #include "system.h"
28 #include "group-list.h"
29 #include "quote.h"
30
31 /* The official name of this program (e.g., no 'g' prefix). */
32 #define PROGRAM_NAME "groups"
33
34 #define AUTHORS \
35 proper_name ("David MacKenzie"), \
36 proper_name ("James Youngman")
37
38
39 static struct option const longopts[] =
40 {
41 {GETOPT_HELP_OPTION_DECL},
42 {GETOPT_VERSION_OPTION_DECL},
43 {nullptr, 0, nullptr, 0}
44 };
45
46 void
usage(int status)47 usage (int status)
48 {
49 if (status != EXIT_SUCCESS)
50 emit_try_help ();
51 else
52 {
53 printf (_("Usage: %s [OPTION]... [USERNAME]...\n"), program_name);
54 fputs (_("\
55 Print group memberships for each USERNAME or, if no USERNAME is specified, for\
56 \n\
57 the current process (which may differ if the groups database has changed).\n"),
58 stdout);
59 fputs (HELP_OPTION_DESCRIPTION, stdout);
60 fputs (VERSION_OPTION_DESCRIPTION, stdout);
61 emit_ancillary_info (PROGRAM_NAME);
62 }
63 exit (status);
64 }
65
66 int
main(int argc,char ** argv)67 main (int argc, char **argv)
68 {
69 int optc;
70 bool ok = true;
71 gid_t rgid, egid;
72 uid_t ruid;
73
74 initialize_main (&argc, &argv);
75 set_program_name (argv[0]);
76 setlocale (LC_ALL, "");
77 bindtextdomain (PACKAGE, LOCALEDIR);
78 textdomain (PACKAGE);
79
80 atexit (close_stdout);
81
82 /* Processing the arguments this way makes groups.c behave differently to
83 * groups.sh if one of the arguments is "--".
84 */
85 while ((optc = getopt_long (argc, argv, "", longopts, nullptr)) != -1)
86 {
87 switch (optc)
88 {
89 case_GETOPT_HELP_CHAR;
90 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
91 default:
92 usage (EXIT_FAILURE);
93 }
94 }
95
96 if (optind == argc)
97 {
98 /* No arguments. Divulge the details of the current process. */
99 uid_t NO_UID = -1;
100 gid_t NO_GID = -1;
101
102 errno = 0;
103 ruid = getuid ();
104 if (ruid == NO_UID && errno)
105 error (EXIT_FAILURE, errno, _("cannot get real UID"));
106
107 errno = 0;
108 egid = getegid ();
109 if (egid == NO_GID && errno)
110 error (EXIT_FAILURE, errno, _("cannot get effective GID"));
111
112 errno = 0;
113 rgid = getgid ();
114 if (rgid == NO_GID && errno)
115 error (EXIT_FAILURE, errno, _("cannot get real GID"));
116
117 if (!print_group_list (nullptr, ruid, rgid, egid, true, ' '))
118 ok = false;
119 putchar ('\n');
120 }
121 else
122 {
123 /* At least one argument. Divulge the details of the specified users. */
124 for ( ; optind < argc; optind++)
125 {
126 struct passwd *pwd = getpwnam (argv[optind]);
127 if (pwd == nullptr)
128 {
129 error (0, 0, _("%s: no such user"), quote (argv[optind]));
130 ok = false;
131 continue;
132 }
133 ruid = pwd->pw_uid;
134 rgid = egid = pwd->pw_gid;
135
136 printf ("%s : ", argv[optind]);
137 if (!print_group_list (argv[optind], ruid, rgid, egid, true, ' '))
138 ok = false;
139 putchar ('\n');
140 }
141 }
142
143 return ok ? EXIT_SUCCESS : EXIT_FAILURE;
144 }
145