1 /* chmod -- change permission modes of files
2 Copyright (C) 89, 90, 91, 1995-2008 Free Software Foundation, Inc.
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.
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.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by David MacKenzie <djm@gnu.ai.mit.edu> */
22 #include <sys/types.h>
28 #include "modechange.h"
31 #include "root-dev-ino.h"
34 /* The official name of this program (e.g., no `g' prefix). */
35 #define PROGRAM_NAME "chmod"
38 proper_name ("David MacKenzie"), \
39 proper_name ("Jim Meyering")
46 CH_NO_CHANGE_REQUESTED
51 /* Print a message for each file that is processed. */
54 /* Print a message for each file whose attributes we change. */
57 /* Do not be verbose. This is the default. */
61 /* The desired change to the mode. */
62 static struct mode_change *change;
64 /* The initial umask value, if it might be needed. */
65 static mode_t umask_value;
67 /* If true, change the modes of directories recursively. */
70 /* If true, force silence (no error messages). */
71 static bool force_silent;
73 /* If true, diagnose surprises from naive misuses like "chmod -r file".
74 POSIX allows diagnostics here, as portable code is supposed to use
75 "chmod -- -r file". */
76 static bool diagnose_surprises;
78 /* Level of verbosity. */
79 static enum Verbosity verbosity = V_off;
81 /* Pointer to the device and inode numbers of `/', when --recursive.
83 static struct dev_ino *root_dev_ino;
85 /* For long options that have no equivalent short option, use a
86 non-character as a pseudo short option, starting with CHAR_MAX + 1. */
89 NO_PRESERVE_ROOT = CHAR_MAX + 1,
94 static struct option const long_options[] =
96 {"changes", no_argument, NULL, 'c'},
97 {"recursive", no_argument, NULL, 'R'},
98 {"no-preserve-root", no_argument, NULL, NO_PRESERVE_ROOT},
99 {"preserve-root", no_argument, NULL, PRESERVE_ROOT},
100 {"quiet", no_argument, NULL, 'f'},
101 {"reference", required_argument, NULL, REFERENCE_FILE_OPTION},
102 {"silent", no_argument, NULL, 'f'},
103 {"verbose", no_argument, NULL, 'v'},
104 {GETOPT_HELP_OPTION_DECL},
105 {GETOPT_VERSION_OPTION_DECL},
109 /* Return true if the chmodable permission bits of FILE changed.
110 The old mode was OLD_MODE, but it was changed to NEW_MODE. */
113 mode_changed (char const *file, mode_t old_mode, mode_t new_mode)
115 if (new_mode & (S_ISUID | S_ISGID | S_ISVTX))
117 /* The new mode contains unusual bits that the call to chmod may
118 have silently cleared. Check whether they actually changed. */
120 struct stat new_stats;
122 if (stat (file, &new_stats) != 0)
125 error (0, errno, _("getting new attributes of %s"), quote (file));
129 new_mode = new_stats.st_mode;
132 return ((old_mode ^ new_mode) & CHMOD_MODE_BITS) != 0;
135 /* Tell the user how/if the MODE of FILE has been changed.
136 CHANGED describes what (if anything) has happened. */
139 describe_change (const char *file, mode_t mode,
140 enum Change_status changed)
142 char perms[12]; /* "-rwxrwxrwx" ls-style modes. */
145 if (changed == CH_NOT_APPLIED)
147 printf (_("neither symbolic link %s nor referent has been changed\n"),
152 strmode (mode, perms);
153 perms[10] = '\0'; /* Remove trailing space. */
157 fmt = _("mode of %s changed to %04lo (%s)\n");
160 fmt = _("failed to change mode of %s to %04lo (%s)\n");
162 case CH_NO_CHANGE_REQUESTED:
163 fmt = _("mode of %s retained as %04lo (%s)\n");
168 printf (fmt, quote (file),
169 (unsigned long int) (mode & CHMOD_MODE_BITS), &perms[1]);
172 /* Change the mode of FILE.
173 Return true if successful. This function is called
174 once for every file system object that fts encounters. */
177 process_file (FTS *fts, FTSENT *ent)
179 char const *file_full_name = ent->fts_path;
180 char const *file = ent->fts_accpath;
181 const struct stat *file_stats = ent->fts_statp;
182 mode_t old_mode IF_LINT (= 0);
183 mode_t new_mode IF_LINT (= 0);
185 bool chmod_succeeded = false;
187 switch (ent->fts_info)
193 /* For a top-level file or directory, this FTS_NS (stat failed)
194 indicator is determined at the time of the initial fts_open call.
195 With programs like chmod, chown, and chgrp, that modify
196 permissions, it is possible that the file in question is
197 accessible when control reaches this point. So, if this is
198 the first time we've seen the FTS_NS for this file, tell
199 fts_read to stat it "again". */
200 if (ent->fts_level == 0 && ent->fts_number == 0)
203 fts_set (fts, ent, FTS_AGAIN);
206 error (0, ent->fts_errno, _("cannot access %s"), quote (file_full_name));
211 error (0, ent->fts_errno, _("%s"), quote (file_full_name));
216 error (0, ent->fts_errno, _("cannot read directory %s"),
217 quote (file_full_name));
222 error (0, 0, _("cannot operate on dangling symlink %s"),
223 quote (file_full_name));
230 if (ok && ROOT_DEV_INO_CHECK (root_dev_ino, file_stats))
232 ROOT_DEV_INO_WARN (file_full_name);
233 /* Tell fts not to traverse into this hierarchy. */
234 fts_set (fts, ent, FTS_SKIP);
235 /* Ensure that we do not process "/" on the second visit. */
236 ent = fts_read (fts);
242 old_mode = file_stats->st_mode;
243 new_mode = mode_adjust (old_mode, S_ISDIR (old_mode) != 0, umask_value,
246 if (! S_ISLNK (old_mode))
248 if (chmodat (fts->fts_cwd_fd, file, new_mode) == 0)
249 chmod_succeeded = true;
253 error (0, errno, _("changing permissions of %s"),
254 quote (file_full_name));
260 if (verbosity != V_off)
262 bool changed = (chmod_succeeded
263 && mode_changed (file, old_mode, new_mode));
265 if (changed || verbosity == V_high)
267 enum Change_status ch_status =
269 : !chmod_succeeded ? CH_NOT_APPLIED
270 : !changed ? CH_NO_CHANGE_REQUESTED
272 describe_change (file_full_name, new_mode, ch_status);
276 if (chmod_succeeded & diagnose_surprises)
278 mode_t naively_expected_mode =
279 mode_adjust (old_mode, S_ISDIR (old_mode) != 0, 0, change, NULL);
280 if (new_mode & ~naively_expected_mode)
283 char naively_expected_perms[12];
284 strmode (new_mode, new_perms);
285 strmode (naively_expected_mode, naively_expected_perms);
286 new_perms[10] = naively_expected_perms[10] = '\0';
288 _("%s: new permissions are %s, not %s"),
289 quotearg_colon (file_full_name),
290 new_perms + 1, naively_expected_perms + 1);
296 fts_set (fts, ent, FTS_SKIP);
301 /* Recursively change the modes of the specified FILES (the last entry
302 of which is NULL). BIT_FLAGS controls how fts works.
303 Return true if successful. */
306 process_files (char **files, int bit_flags)
310 FTS *fts = xfts_open (files, bit_flags, NULL);
316 ent = fts_read (fts);
321 /* FIXME: try to give a better message */
322 error (0, errno, _("fts_read failed"));
328 ok &= process_file (fts, ent);
331 /* Ignore failure, since the only way it can do so is in failing to
332 return to the original directory, and since we're about to exit,
333 that doesn't matter. */
342 if (status != EXIT_SUCCESS)
343 fprintf (stderr, _("Try `%s --help' for more information.\n"),
348 Usage: %s [OPTION]... MODE[,MODE]... FILE...\n\
349 or: %s [OPTION]... OCTAL-MODE FILE...\n\
350 or: %s [OPTION]... --reference=RFILE FILE...\n\
352 program_name, program_name, program_name);
354 Change the mode of each FILE to MODE.\n\
356 -c, --changes like verbose but report only when a change is made\n\
359 --no-preserve-root do not treat `/' specially (the default)\n\
360 --preserve-root fail to operate recursively on `/'\n\
363 -f, --silent, --quiet suppress most error messages\n\
364 -v, --verbose output a diagnostic for every file processed\n\
365 --reference=RFILE use RFILE's mode instead of MODE values\n\
366 -R, --recursive change files and directories recursively\n\
368 fputs (HELP_OPTION_DESCRIPTION, stdout);
369 fputs (VERSION_OPTION_DESCRIPTION, stdout);
372 Each MODE is of the form `[ugoa]*([-+=]([rwxXst]*|[ugo]))+'.\n\
374 emit_bug_reporting_address ();
379 /* Parse the ASCII mode given on the command line into a linked list
380 of `struct mode_change' and apply that to each file argument. */
383 main (int argc, char **argv)
387 size_t mode_alloc = 0;
389 bool preserve_root = false;
390 char const *reference_file = NULL;
393 initialize_main (&argc, &argv);
394 set_program_name (argv[0]);
395 setlocale (LC_ALL, "");
396 bindtextdomain (PACKAGE, LOCALEDIR);
397 textdomain (PACKAGE);
399 atexit (close_stdout);
401 recurse = force_silent = diagnose_surprises = false;
403 while ((c = getopt_long (argc, argv,
404 "Rcfvr::w::x::X::s::t::u::g::o::a::,::+::=::",
423 /* Support nonportable uses like "chmod -w", but diagnose
424 surprises due to umask confusion. Even though "--", "--r",
425 etc., are valid modes, there is no "case '-'" here since
426 getopt_long reserves leading "--" for long options. */
428 /* Allocate a mode string (e.g., "-rwx") by concatenating
429 the argument containing this option. If a previous mode
430 string was given, concatenate the previous string, a
431 comma, and the new string (e.g., "-s,-rwx"). */
433 char const *arg = argv[optind - 1];
434 size_t arg_len = strlen (arg);
435 size_t mode_comma_len = mode_len + !!mode_len;
436 size_t new_mode_len = mode_comma_len + arg_len;
437 if (mode_alloc <= new_mode_len)
439 mode_alloc = new_mode_len + 1;
440 mode = X2REALLOC (mode, &mode_alloc);
442 mode[mode_len] = ',';
443 strcpy (mode + mode_comma_len, arg);
444 mode_len = new_mode_len;
446 diagnose_surprises = true;
449 case NO_PRESERVE_ROOT:
450 preserve_root = false;
453 preserve_root = true;
455 case REFERENCE_FILE_OPTION:
456 reference_file = optarg;
462 verbosity = V_changes_only;
470 case_GETOPT_HELP_CHAR;
471 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
473 usage (EXIT_FAILURE);
481 error (0, 0, _("cannot combine mode and --reference options"));
482 usage (EXIT_FAILURE);
488 mode = argv[optind++];
493 if (!mode || mode != argv[optind - 1])
494 error (0, 0, _("missing operand"));
496 error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
497 usage (EXIT_FAILURE);
502 change = mode_create_from_ref (reference_file);
504 error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
505 quote (reference_file));
509 change = mode_compile (mode);
512 error (0, 0, _("invalid mode: %s"), quote (mode));
513 usage (EXIT_FAILURE);
515 umask_value = umask (0);
518 if (recurse & preserve_root)
520 static struct dev_ino dev_ino_buf;
521 root_dev_ino = get_root_dev_ino (&dev_ino_buf);
522 if (root_dev_ino == NULL)
523 error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
531 ok = process_files (argv + optind, FTS_COMFOLLOW | FTS_PHYSICAL);
533 exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);