1 /* chgrp -- change group ownership of files
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 David MacKenzie <djm@gnu.ai.mit.edu>. */
18
19 #include <config.h>
20 #include <stdio.h>
21 #include <sys/types.h>
22 #include <grp.h>
23 #include <getopt.h>
24
25 #include "system.h"
26 #include "chown-core.h"
27 #include "fts_.h"
28 #include "quote.h"
29 #include "root-dev-ino.h"
30 #include "xstrtol.h"
31
32 /* The official name of this program (e.g., no 'g' prefix). */
33 #define PROGRAM_NAME "chgrp"
34
35 #define AUTHORS \
36 proper_name ("David MacKenzie"), \
37 proper_name ("Jim Meyering")
38
39 #if ! HAVE_ENDGRENT
40 # define endgrent() ((void) 0)
41 #endif
42
43 /* The argument to the --reference option. Use the group ID of this file.
44 This file must exist. */
45 static char *reference_file;
46
47 /* For long options that have no equivalent short option, use a
48 non-character as a pseudo short option, starting with CHAR_MAX + 1. */
49 enum
50 {
51 DEREFERENCE_OPTION = CHAR_MAX + 1,
52 NO_PRESERVE_ROOT,
53 PRESERVE_ROOT,
54 REFERENCE_FILE_OPTION
55 };
56
57 static struct option const long_options[] =
58 {
59 {"recursive", no_argument, nullptr, 'R'},
60 {"changes", no_argument, nullptr, 'c'},
61 {"dereference", no_argument, nullptr, DEREFERENCE_OPTION},
62 {"no-dereference", no_argument, nullptr, 'h'},
63 {"no-preserve-root", no_argument, nullptr, NO_PRESERVE_ROOT},
64 {"preserve-root", no_argument, nullptr, PRESERVE_ROOT},
65 {"quiet", no_argument, nullptr, 'f'},
66 {"silent", no_argument, nullptr, 'f'},
67 {"reference", required_argument, nullptr, REFERENCE_FILE_OPTION},
68 {"verbose", no_argument, nullptr, 'v'},
69 {GETOPT_HELP_OPTION_DECL},
70 {GETOPT_VERSION_OPTION_DECL},
71 {nullptr, 0, nullptr, 0}
72 };
73
74 /* Return the group ID of NAME, or -1 if no name was specified. */
75
76 static gid_t
77 parse_group (char const *name)
78 {
79 gid_t gid = -1;
80
81 if (*name)
82 {
83 struct group *grp = getgrnam (name);
84 if (grp)
85 gid = grp->gr_gid;
86 else
87 {
88 uintmax_t tmp;
89 if (! (xstrtoumax (name, nullptr, 10, &tmp, "") == LONGINT_OK
90 && tmp <= GID_T_MAX))
91 error (EXIT_FAILURE, 0, _("invalid group: %s"),
92 quote (name));
93 gid = tmp;
94 }
95 endgrent (); /* Save a file descriptor. */
96 }
97
98 return gid;
99 }
100
101 void
102 usage (int status)
103 {
104 if (status != EXIT_SUCCESS)
105 emit_try_help ();
106 else
107 {
108 printf (_("\
109 Usage: %s [OPTION]... GROUP FILE...\n\
110 or: %s [OPTION]... --reference=RFILE FILE...\n\
111 "),
112 program_name, program_name);
113 fputs (_("\
114 Change the group of each FILE to GROUP.\n\
115 With --reference, change the group of each FILE to that of RFILE.\n\
116 \n\
117 "), stdout);
118 fputs (_("\
119 -c, --changes like verbose but report only when a change is made\n\
120 -f, --silent, --quiet suppress most error messages\n\
121 -v, --verbose output a diagnostic for every file processed\n\
122 "), stdout);
123 fputs (_("\
124 --dereference affect the referent of each symbolic link (this is\n\
125 the default), rather than the symbolic link itself\n\
126 -h, --no-dereference affect symbolic links instead of any referenced file\n\
127 "), stdout);
128 fputs (_("\
129 (useful only on systems that can change the\n\
130 ownership of a symlink)\n\
131 "), stdout);
132 fputs (_("\
133 --no-preserve-root do not treat '/' specially (the default)\n\
134 --preserve-root fail to operate recursively on '/'\n\
135 "), stdout);
136 fputs (_("\
137 --reference=RFILE use RFILE's group rather than specifying a GROUP.\n\
138 RFILE is always dereferenced if a symbolic link.\n\
139 "), stdout);
140 fputs (_("\
141 -R, --recursive operate on files and directories recursively\n\
142 "), stdout);
143 fputs (_("\
144 \n\
145 The following options modify how a hierarchy is traversed when the -R\n\
146 option is also specified. If more than one is specified, only the final\n\
147 one takes effect.\n\
148 \n\
149 -H if a command line argument is a symbolic link\n\
150 to a directory, traverse it\n\
151 -L traverse every symbolic link to a directory\n\
152 encountered\n\
153 -P do not traverse any symbolic links (default)\n\
154 \n\
155 "), stdout);
156 fputs (HELP_OPTION_DESCRIPTION, stdout);
157 fputs (VERSION_OPTION_DESCRIPTION, stdout);
158 printf (_("\
159 \n\
160 Examples:\n\
161 %s staff /u Change the group of /u to \"staff\".\n\
162 %s -hR staff /u Change the group of /u and subfiles to \"staff\".\n\
163 "),
164 program_name, program_name);
165 emit_ancillary_info (PROGRAM_NAME);
166 }
167 exit (status);
168 }
169
170 int
171 main (int argc, char **argv)
172 {
173 bool preserve_root = false;
174 gid_t gid;
175
176 /* Bit flags that control how fts works. */
177 int bit_flags = FTS_PHYSICAL;
178
179 /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
180 specified. */
181 int dereference = -1;
182
183 struct Chown_option chopt;
184 bool ok;
185 int optc;
186
187 initialize_main (&argc, &argv);
188 set_program_name (argv[0]);
189 setlocale (LC_ALL, "");
190 bindtextdomain (PACKAGE, LOCALEDIR);
191 textdomain (PACKAGE);
192
193 atexit (close_stdout);
194
195 chopt_init (&chopt);
196
197 while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, nullptr))
198 != -1)
199 {
200 switch (optc)
201 {
202 case 'H': /* Traverse command-line symlinks-to-directories. */
203 bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
204 break;
205
206 case 'L': /* Traverse all symlinks-to-directories. */
207 bit_flags = FTS_LOGICAL;
208 break;
209
210 case 'P': /* Traverse no symlinks-to-directories. */
211 bit_flags = FTS_PHYSICAL;
212 break;
213
214 case 'h': /* --no-dereference: affect symlinks */
215 dereference = 0;
216 break;
217
218 case DEREFERENCE_OPTION: /* --dereference: affect the referent
219 of each symlink */
220 dereference = 1;
221 break;
222
223 case NO_PRESERVE_ROOT:
224 preserve_root = false;
225 break;
226
227 case PRESERVE_ROOT:
228 preserve_root = true;
229 break;
230
231 case REFERENCE_FILE_OPTION:
232 reference_file = optarg;
233 break;
234
235 case 'R':
236 chopt.recurse = true;
237 break;
238
239 case 'c':
240 chopt.verbosity = V_changes_only;
241 break;
242
243 case 'f':
244 chopt.force_silent = true;
245 break;
246
247 case 'v':
248 chopt.verbosity = V_high;
249 break;
250
251 case_GETOPT_HELP_CHAR;
252 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
253 default:
254 usage (EXIT_FAILURE);
255 }
256 }
257
258 if (chopt.recurse)
259 {
260 if (bit_flags == FTS_PHYSICAL)
261 {
262 if (dereference == 1)
263 error (EXIT_FAILURE, 0,
264 _("-R --dereference requires either -H or -L"));
265 dereference = 0;
266 }
267 }
268 else
269 {
270 bit_flags = FTS_PHYSICAL;
271 }
272 chopt.affect_symlink_referent = (dereference != 0);
273
274 if (argc - optind < (reference_file ? 1 : 2))
275 {
276 if (argc <= optind)
277 error (0, 0, _("missing operand"));
278 else
279 error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
280 usage (EXIT_FAILURE);
281 }
282
283 if (reference_file)
284 {
285 struct stat ref_stats;
286 if (stat (reference_file, &ref_stats))
287 error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
288 quoteaf (reference_file));
289
290 gid = ref_stats.st_gid;
291 chopt.group_name = gid_to_name (ref_stats.st_gid);
292 }
293 else
294 {
295 char *group_name = argv[optind++];
296 chopt.group_name = (*group_name ? xstrdup (group_name) : nullptr);
297 gid = parse_group (group_name);
298 }
299
300 if (chopt.recurse && preserve_root)
301 {
302 static struct dev_ino dev_ino_buf;
303 chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
304 if (chopt.root_dev_ino == nullptr)
305 error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
306 quoteaf ("/"));
307 }
308
309 bit_flags |= FTS_DEFER_STAT;
310 ok = chown_files (argv + optind, bit_flags,
311 (uid_t) -1, gid,
312 (uid_t) -1, (gid_t) -1, &chopt);
313
314 main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
315 }