1 /* chmod -- change permission modes of files
2 Copyright (C) 1989-2019 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 <https://www.gnu.org/licenses/>. */
17 /* Written by David MacKenzie <djm@gnu.ai.mit.edu> */
22 #include <sys/types.h>
29 #include "ignore-value.h"
30 #include "modechange.h"
32 #include "root-dev-ino.h"
35 /* The official name of this program (e.g., no 'g' prefix). */
36 #define PROGRAM_NAME "chmod"
39 proper_name ("David MacKenzie"), \
40 proper_name ("Jim Meyering")
47 CH_NO_CHANGE_REQUESTED
52 /* Print a message for each file that is processed. */
55 /* Print a message for each file whose attributes we change. */
58 /* Do not be verbose. This is the default. */
62 /* The desired change to the mode. */
63 static struct mode_change
*change
;
65 /* The initial umask value, if it might be needed. */
66 static mode_t umask_value
;
68 /* If true, change the modes of directories recursively. */
71 /* If true, force silence (suppress most of error messages). */
72 static bool force_silent
;
74 /* If true, diagnose surprises from naive misuses like "chmod -r file".
75 POSIX allows diagnostics here, as portable code is supposed to use
76 "chmod -- -r file". */
77 static bool diagnose_surprises
;
79 /* Level of verbosity. */
80 static enum Verbosity verbosity
= V_off
;
82 /* Pointer to the device and inode numbers of '/', when --recursive.
84 static struct dev_ino
*root_dev_ino
;
86 /* For long options that have no equivalent short option, use a
87 non-character as a pseudo short option, starting with CHAR_MAX + 1. */
90 NO_PRESERVE_ROOT
= CHAR_MAX
+ 1,
95 static struct option
const long_options
[] =
97 {"changes", no_argument
, NULL
, 'c'},
98 {"recursive", no_argument
, NULL
, 'R'},
99 {"no-preserve-root", no_argument
, NULL
, NO_PRESERVE_ROOT
},
100 {"preserve-root", no_argument
, NULL
, PRESERVE_ROOT
},
101 {"quiet", no_argument
, NULL
, 'f'},
102 {"reference", required_argument
, NULL
, REFERENCE_FILE_OPTION
},
103 {"silent", no_argument
, NULL
, 'f'},
104 {"verbose", no_argument
, NULL
, 'v'},
105 {GETOPT_HELP_OPTION_DECL
},
106 {GETOPT_VERSION_OPTION_DECL
},
110 /* Return true if the chmodable permission bits of FILE changed.
111 The old mode was OLD_MODE, but it was changed to NEW_MODE. */
114 mode_changed (int dir_fd
, char const *file
, char const *file_full_name
,
115 mode_t old_mode
, mode_t new_mode
)
117 if (new_mode
& (S_ISUID
| S_ISGID
| S_ISVTX
))
119 /* The new mode contains unusual bits that the call to chmod may
120 have silently cleared. Check whether they actually changed. */
122 struct stat new_stats
;
124 if (fstatat (dir_fd
, file
, &new_stats
, 0) != 0)
127 error (0, errno
, _("getting new attributes of %s"),
128 quoteaf (file_full_name
));
132 new_mode
= new_stats
.st_mode
;
135 return ((old_mode
^ new_mode
) & CHMOD_MODE_BITS
) != 0;
138 /* Tell the user how/if the MODE of FILE has been changed.
139 CHANGED describes what (if anything) has happened. */
142 describe_change (const char *file
, mode_t old_mode
, mode_t mode
,
143 enum Change_status changed
)
145 char perms
[12]; /* "-rwxrwxrwx" ls-style modes. */
149 if (changed
== CH_NOT_APPLIED
)
151 printf (_("neither symbolic link %s nor referent has been changed\n"),
156 strmode (mode
, perms
);
157 perms
[10] = '\0'; /* Remove trailing space. */
159 strmode (old_mode
, old_perms
);
160 old_perms
[10] = '\0'; /* Remove trailing space. */
165 fmt
= _("mode of %s changed from %04lo (%s) to %04lo (%s)\n");
168 fmt
= _("failed to change mode of %s from %04lo (%s) to %04lo (%s)\n");
170 case CH_NO_CHANGE_REQUESTED
:
171 fmt
= _("mode of %s retained as %04lo (%s)\n");
172 printf (fmt
, quoteaf (file
),
173 (unsigned long int) (mode
& CHMOD_MODE_BITS
), &perms
[1]);
178 printf (fmt
, quoteaf (file
),
179 (unsigned long int) (old_mode
& CHMOD_MODE_BITS
), &old_perms
[1],
180 (unsigned long int) (mode
& CHMOD_MODE_BITS
), &perms
[1]);
183 /* Change the mode of FILE.
184 Return true if successful. This function is called
185 once for every file system object that fts encounters. */
188 process_file (FTS
*fts
, FTSENT
*ent
)
190 char const *file_full_name
= ent
->fts_path
;
191 char const *file
= ent
->fts_accpath
;
192 const struct stat
*file_stats
= ent
->fts_statp
;
193 mode_t old_mode
IF_LINT ( = 0);
194 mode_t new_mode
IF_LINT ( = 0);
196 bool chmod_succeeded
= false;
198 switch (ent
->fts_info
)
204 /* For a top-level file or directory, this FTS_NS (stat failed)
205 indicator is determined at the time of the initial fts_open call.
206 With programs like chmod, chown, and chgrp, that modify
207 permissions, it is possible that the file in question is
208 accessible when control reaches this point. So, if this is
209 the first time we've seen the FTS_NS for this file, tell
210 fts_read to stat it "again". */
211 if (ent
->fts_level
== 0 && ent
->fts_number
== 0)
214 fts_set (fts
, ent
, FTS_AGAIN
);
218 error (0, ent
->fts_errno
, _("cannot access %s"),
219 quoteaf (file_full_name
));
225 error (0, ent
->fts_errno
, "%s", quotef (file_full_name
));
231 error (0, ent
->fts_errno
, _("cannot read directory %s"),
232 quoteaf (file_full_name
));
238 error (0, 0, _("cannot operate on dangling symlink %s"),
239 quoteaf (file_full_name
));
243 case FTS_DC
: /* directory that causes cycles */
244 if (cycle_warning_required (fts
, ent
))
246 emit_cycle_warning (file_full_name
);
255 if (ok
&& ROOT_DEV_INO_CHECK (root_dev_ino
, file_stats
))
257 ROOT_DEV_INO_WARN (file_full_name
);
258 /* Tell fts not to traverse into this hierarchy. */
259 fts_set (fts
, ent
, FTS_SKIP
);
260 /* Ensure that we do not process "/" on the second visit. */
261 ignore_value (fts_read (fts
));
267 old_mode
= file_stats
->st_mode
;
268 new_mode
= mode_adjust (old_mode
, S_ISDIR (old_mode
) != 0, umask_value
,
271 if (! S_ISLNK (old_mode
))
273 if (chmodat (fts
->fts_cwd_fd
, file
, new_mode
) == 0)
274 chmod_succeeded
= true;
278 error (0, errno
, _("changing permissions of %s"),
279 quoteaf (file_full_name
));
285 if (verbosity
!= V_off
)
287 bool changed
= (chmod_succeeded
288 && mode_changed (fts
->fts_cwd_fd
, file
, file_full_name
,
289 old_mode
, new_mode
));
291 if (changed
|| verbosity
== V_high
)
293 enum Change_status ch_status
=
295 : !chmod_succeeded
? CH_NOT_APPLIED
296 : !changed
? CH_NO_CHANGE_REQUESTED
298 describe_change (file_full_name
, old_mode
, new_mode
, ch_status
);
302 if (chmod_succeeded
&& diagnose_surprises
)
304 mode_t naively_expected_mode
=
305 mode_adjust (old_mode
, S_ISDIR (old_mode
) != 0, 0, change
, NULL
);
306 if (new_mode
& ~naively_expected_mode
)
309 char naively_expected_perms
[12];
310 strmode (new_mode
, new_perms
);
311 strmode (naively_expected_mode
, naively_expected_perms
);
312 new_perms
[10] = naively_expected_perms
[10] = '\0';
314 _("%s: new permissions are %s, not %s"),
315 quotef (file_full_name
),
316 new_perms
+ 1, naively_expected_perms
+ 1);
322 fts_set (fts
, ent
, FTS_SKIP
);
327 /* Recursively change the modes of the specified FILES (the last entry
328 of which is NULL). BIT_FLAGS controls how fts works.
329 Return true if successful. */
332 process_files (char **files
, int bit_flags
)
336 FTS
*fts
= xfts_open (files
, bit_flags
, NULL
);
342 ent
= fts_read (fts
);
347 /* FIXME: try to give a better message */
349 error (0, errno
, _("fts_read failed"));
355 ok
&= process_file (fts
, ent
);
358 if (fts_close (fts
) != 0)
360 error (0, errno
, _("fts_close failed"));
370 if (status
!= EXIT_SUCCESS
)
375 Usage: %s [OPTION]... MODE[,MODE]... FILE...\n\
376 or: %s [OPTION]... OCTAL-MODE FILE...\n\
377 or: %s [OPTION]... --reference=RFILE FILE...\n\
379 program_name
, program_name
, program_name
);
381 Change the mode of each FILE to MODE.\n\
382 With --reference, change the mode of each FILE to that of RFILE.\n\
386 -c, --changes like verbose but report only when a change is made\n\
387 -f, --silent, --quiet suppress most error messages\n\
388 -v, --verbose output a diagnostic for every file processed\n\
391 --no-preserve-root do not treat '/' specially (the default)\n\
392 --preserve-root fail to operate recursively on '/'\n\
395 --reference=RFILE use RFILE's mode instead of MODE values\n\
398 -R, --recursive change files and directories recursively\n\
400 fputs (HELP_OPTION_DESCRIPTION
, stdout
);
401 fputs (VERSION_OPTION_DESCRIPTION
, stdout
);
404 Each MODE is of the form '[ugoa]*([-+=]([rwxXst]*|[ugo]))+|[-+=][0-7]+'.\n\
406 emit_ancillary_info (PROGRAM_NAME
);
411 /* Parse the ASCII mode given on the command line into a linked list
412 of 'struct mode_change' and apply that to each file argument. */
415 main (int argc
, char **argv
)
419 size_t mode_alloc
= 0;
421 bool preserve_root
= false;
422 char const *reference_file
= NULL
;
425 initialize_main (&argc
, &argv
);
426 set_program_name (argv
[0]);
427 setlocale (LC_ALL
, "");
428 bindtextdomain (PACKAGE
, LOCALEDIR
);
429 textdomain (PACKAGE
);
431 atexit (close_stdout
);
433 recurse
= force_silent
= diagnose_surprises
= false;
435 while ((c
= getopt_long (argc
, argv
,
436 ("Rcfvr::w::x::X::s::t::u::g::o::a::,::+::=::"
437 "0::1::2::3::4::5::6::7::"),
456 case '0': case '1': case '2': case '3':
457 case '4': case '5': case '6': case '7':
458 /* Support nonportable uses like "chmod -w", but diagnose
459 surprises due to umask confusion. Even though "--", "--r",
460 etc., are valid modes, there is no "case '-'" here since
461 getopt_long reserves leading "--" for long options. */
463 /* Allocate a mode string (e.g., "-rwx") by concatenating
464 the argument containing this option. If a previous mode
465 string was given, concatenate the previous string, a
466 comma, and the new string (e.g., "-s,-rwx"). */
468 char const *arg
= argv
[optind
- 1];
469 size_t arg_len
= strlen (arg
);
470 size_t mode_comma_len
= mode_len
+ !!mode_len
;
471 size_t new_mode_len
= mode_comma_len
+ arg_len
;
472 if (mode_alloc
<= new_mode_len
)
474 mode_alloc
= new_mode_len
+ 1;
475 mode
= X2REALLOC (mode
, &mode_alloc
);
477 mode
[mode_len
] = ',';
478 memcpy (mode
+ mode_comma_len
, arg
, arg_len
+ 1);
479 mode_len
= new_mode_len
;
481 diagnose_surprises
= true;
484 case NO_PRESERVE_ROOT
:
485 preserve_root
= false;
488 preserve_root
= true;
490 case REFERENCE_FILE_OPTION
:
491 reference_file
= optarg
;
497 verbosity
= V_changes_only
;
505 case_GETOPT_HELP_CHAR
;
506 case_GETOPT_VERSION_CHAR (PROGRAM_NAME
, AUTHORS
);
508 usage (EXIT_FAILURE
);
516 error (0, 0, _("cannot combine mode and --reference options"));
517 usage (EXIT_FAILURE
);
523 mode
= argv
[optind
++];
528 if (!mode
|| mode
!= argv
[optind
- 1])
529 error (0, 0, _("missing operand"));
531 error (0, 0, _("missing operand after %s"), quote (argv
[argc
- 1]));
532 usage (EXIT_FAILURE
);
537 change
= mode_create_from_ref (reference_file
);
539 die (EXIT_FAILURE
, errno
, _("failed to get attributes of %s"),
540 quoteaf (reference_file
));
544 change
= mode_compile (mode
);
547 error (0, 0, _("invalid mode: %s"), quote (mode
));
548 usage (EXIT_FAILURE
);
550 umask_value
= umask (0);
553 if (recurse
&& preserve_root
)
555 static struct dev_ino dev_ino_buf
;
556 root_dev_ino
= get_root_dev_ino (&dev_ino_buf
);
557 if (root_dev_ino
== NULL
)
558 die (EXIT_FAILURE
, errno
, _("failed to get attributes of %s"),
566 ok
= process_files (argv
+ optind
,
567 FTS_COMFOLLOW
| FTS_PHYSICAL
| FTS_DEFER_STAT
);
569 IF_LINT (free (change
));
571 return ok
? EXIT_SUCCESS
: EXIT_FAILURE
;