1 /* touch -- change modification and access times of files
2 Copyright (C) 1987-2020 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 Paul Rubin, Arnold Robbins, Jim Kingdon, David MacKenzie,
18 and Randy Smith. */
19
20 #include <config.h>
21 #include <stdio.h>
22 #include <getopt.h>
23 #include <sys/types.h>
24 #include <assert.h>
25
26 #include "system.h"
27 #include "argmatch.h"
28 #include "die.h"
29 #include "error.h"
30 #include "fd-reopen.h"
31 #include "parse-datetime.h"
32 #include "posixtm.h"
33 #include "posixver.h"
34 #include "quote.h"
35 #include "stat-time.h"
36 #include "utimens.h"
37
38 /* The official name of this program (e.g., no 'g' prefix). */
39 #define PROGRAM_NAME "touch"
40
41 #define AUTHORS \
42 proper_name ("Paul Rubin"), \
43 proper_name ("Arnold Robbins"), \
44 proper_name ("Jim Kingdon"), \
45 proper_name ("David MacKenzie"), \
46 proper_name ("Randy Smith")
47
48 /* Bitmasks for 'change_times'. */
49 #define CH_ATIME 1
50 #define CH_MTIME 2
51
52 /* Which timestamps to change. */
53 static int change_times;
54
55 /* (-c) If true, don't create if not already there. */
56 static bool no_create;
57
58 /* (-r) If true, use times from a reference file. */
59 static bool use_ref;
60
61 /* (-h) If true, change the times of an existing symlink, if possible. */
62 static bool no_dereference;
63
64 /* If true, the only thing we have to do is change both the
65 modification and access time to the current time, so we don't
66 have to own the file, just be able to read and write it.
67 On some systems, we can do this if we own the file, even though
68 we have neither read nor write access to it. */
69 static bool amtime_now;
70
71 /* New access and modification times to use when setting time. */
72 static struct timespec newtime[2];
73
74 /* File to use for -r. */
75 static char *ref_file;
76
77 /* For long options that have no equivalent short option, use a
78 non-character as a pseudo short option, starting with CHAR_MAX + 1. */
79 enum
80 {
81 TIME_OPTION = CHAR_MAX + 1
82 };
83
84 static struct option const longopts[] =
85 {
86 {"time", required_argument, NULL, TIME_OPTION},
87 {"no-create", no_argument, NULL, 'c'},
88 {"date", required_argument, NULL, 'd'},
89 {"reference", required_argument, NULL, 'r'},
90 {"no-dereference", no_argument, NULL, 'h'},
91 {GETOPT_HELP_OPTION_DECL},
92 {GETOPT_VERSION_OPTION_DECL},
93 {NULL, 0, NULL, 0}
94 };
95
96 /* Valid arguments to the '--time' option. */
97 static char const* const time_args[] =
98 {
99 "atime", "access", "use", "mtime", "modify", NULL
100 };
101
102 /* The bits in 'change_times' that those arguments set. */
103 static int const time_masks[] =
104 {
105 CH_ATIME, CH_ATIME, CH_ATIME, CH_MTIME, CH_MTIME
106 };
107
108 /* Store into *RESULT the result of interpreting FLEX_DATE as a date,
109 relative to NOW. If NOW is null, use the current time. */
110
111 static void
get_reldate(struct timespec * result,char const * flex_date,struct timespec const * now)112 get_reldate (struct timespec *result,
113 char const *flex_date, struct timespec const *now)
114 {
115 if (! parse_datetime (result, flex_date, now))
116 die (EXIT_FAILURE, 0, _("invalid date format %s"), quote (flex_date));
117 }
118
119 /* Update the time of file FILE according to the options given.
120 Return true if successful. */
121
122 static bool
touch(const char * file)123 touch (const char *file)
124 {
125 bool ok;
126 int fd = -1;
127 int open_errno = 0;
128 struct timespec const *t = newtime;
129
130 if (STREQ (file, "-"))
131 fd = STDOUT_FILENO;
132 else if (! (no_create || no_dereference))
133 {
134 /* Try to open FILE, creating it if necessary. */
135 fd = fd_reopen (STDIN_FILENO, file,
136 O_WRONLY | O_CREAT | O_NONBLOCK | O_NOCTTY, MODE_RW_UGO);
137
138 /* Don't save a copy of errno if it's EISDIR, since that would lead
139 touch to give a bogus diagnostic for e.g., 'touch /' (assuming
140 we don't own / or have write access to it). On Solaris 5.6,
141 and probably other systems, it is EINVAL. On SunOS4, it's EPERM. */
142 if (fd == -1 && errno != EISDIR && errno != EINVAL && errno != EPERM)
143 open_errno = errno;
144 }
145
146 if (change_times != (CH_ATIME | CH_MTIME))
147 {
148 /* We're setting only one of the time values. */
149 if (change_times == CH_MTIME)
150 newtime[0].tv_nsec = UTIME_OMIT;
151 else
152 {
153 assert (change_times == CH_ATIME);
154 newtime[1].tv_nsec = UTIME_OMIT;
155 }
156 }
157
158 if (amtime_now)
159 {
160 /* Pass NULL to futimens so it will not fail if we have
161 write access to the file, but don't own it. */
162 t = NULL;
163 }
164
165 ok = (fdutimensat (fd, AT_FDCWD, (fd == STDOUT_FILENO ? NULL : file), t,
166 (no_dereference && fd == -1) ? AT_SYMLINK_NOFOLLOW : 0)
167 == 0);
168
169 if (fd == STDIN_FILENO)
170 {
171 if (close (STDIN_FILENO) != 0)
172 {
173 error (0, errno, _("failed to close %s"), quoteaf (file));
174 return false;
175 }
176 }
177 else if (fd == STDOUT_FILENO)
178 {
179 /* Do not diagnose "touch -c - >&-". */
180 if (!ok && errno == EBADF && no_create)
181 return true;
182 }
183
184 if (!ok)
185 {
186 if (open_errno)
187 {
188 /* The wording of this diagnostic should cover at least two cases:
189 - the file does not exist, but the parent directory is unwritable
190 - the file exists, but it isn't writable
191 I think it's not worth trying to distinguish them. */
192 error (0, open_errno, _("cannot touch %s"), quoteaf (file));
193 }
194 else
195 {
196 if (no_create && errno == ENOENT)
197 return true;
198 error (0, errno, _("setting times of %s"), quoteaf (file));
199 }
200 return false;
201 }
202
203 return true;
204 }
205
206 void
usage(int status)207 usage (int status)
208 {
209 if (status != EXIT_SUCCESS)
210 emit_try_help ();
211 else
212 {
213 printf (_("Usage: %s [OPTION]... FILE...\n"), program_name);
214 fputs (_("\
215 Update the access and modification times of each FILE to the current time.\n\
216 \n\
217 A FILE argument that does not exist is created empty, unless -c or -h\n\
218 is supplied.\n\
219 \n\
220 A FILE argument string of - is handled specially and causes touch to\n\
221 change the times of the file associated with standard output.\n\
222 "), stdout);
223
224 emit_mandatory_arg_note ();
225
226 fputs (_("\
227 -a change only the access time\n\
228 -c, --no-create do not create any files\n\
229 -d, --date=STRING parse STRING and use it instead of current time\n\
230 -f (ignored)\n\
231 "), stdout);
232 fputs (_("\
233 -h, --no-dereference affect each symbolic link instead of any referenced\n\
234 file (useful only on systems that can change the\n\
235 timestamps of a symlink)\n\
236 -m change only the modification time\n\
237 "), stdout);
238 fputs (_("\
239 -r, --reference=FILE use this file's times instead of current time\n\
240 -t STAMP use [[CC]YY]MMDDhhmm[.ss] instead of current time\n\
241 --time=WORD change the specified time:\n\
242 WORD is access, atime, or use: equivalent to -a\n\
243 WORD is modify or mtime: equivalent to -m\n\
244 "), stdout);
245 fputs (HELP_OPTION_DESCRIPTION, stdout);
246 fputs (VERSION_OPTION_DESCRIPTION, stdout);
247 fputs (_("\
248 \n\
249 Note that the -d and -t options accept different time-date formats.\n\
250 "), stdout);
251 emit_ancillary_info (PROGRAM_NAME);
252 }
253 exit (status);
254 }
255
256 int
main(int argc,char ** argv)257 main (int argc, char **argv)
258 {
259 int c;
260 bool date_set = false;
261 bool ok = true;
262 char const *flex_date = NULL;
263
264 initialize_main (&argc, &argv);
265 set_program_name (argv[0]);
266 setlocale (LC_ALL, "");
267 bindtextdomain (PACKAGE, LOCALEDIR);
268 textdomain (PACKAGE);
269
270 atexit (close_stdout);
271
272 change_times = 0;
273 no_create = use_ref = false;
274
275 while ((c = getopt_long (argc, argv, "acd:fhmr:t:", longopts, NULL)) != -1)
276 {
277 switch (c)
278 {
279 case 'a':
280 change_times |= CH_ATIME;
281 break;
282
283 case 'c':
284 no_create = true;
285 break;
286
287 case 'd':
288 flex_date = optarg;
289 break;
290
291 case 'f':
292 break;
293
294 case 'h':
295 no_dereference = true;
296 break;
297
298 case 'm':
299 change_times |= CH_MTIME;
300 break;
301
302 case 'r':
303 use_ref = true;
304 ref_file = optarg;
305 break;
306
307 case 't':
308 if (! posixtime (&newtime[0].tv_sec, optarg,
309 PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS))
310 die (EXIT_FAILURE, 0, _("invalid date format %s"),
311 quote (optarg));
312 newtime[0].tv_nsec = 0;
313 newtime[1] = newtime[0];
314 date_set = true;
315 break;
316
317 case TIME_OPTION: /* --time */
318 change_times |= XARGMATCH ("--time", optarg,
319 time_args, time_masks);
320 break;
321
322 case_GETOPT_HELP_CHAR;
323
324 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
325
326 default:
327 usage (EXIT_FAILURE);
328 }
329 }
330
331 if (change_times == 0)
332 change_times = CH_ATIME | CH_MTIME;
333
334 if (date_set && (use_ref || flex_date))
335 {
336 error (0, 0, _("cannot specify times from more than one source"));
337 usage (EXIT_FAILURE);
338 }
339
340 if (use_ref)
341 {
342 struct stat ref_stats;
343 /* Don't use (no_dereference?lstat:stat) (args), since stat
344 might be an object-like macro. */
345 if (no_dereference ? lstat (ref_file, &ref_stats)
346 : stat (ref_file, &ref_stats))
347 die (EXIT_FAILURE, errno,
348 _("failed to get attributes of %s"), quoteaf (ref_file));
349 newtime[0] = get_stat_atime (&ref_stats);
350 newtime[1] = get_stat_mtime (&ref_stats);
351 date_set = true;
352 if (flex_date)
353 {
354 if (change_times & CH_ATIME)
355 get_reldate (&newtime[0], flex_date, &newtime[0]);
356 if (change_times & CH_MTIME)
357 get_reldate (&newtime[1], flex_date, &newtime[1]);
358 }
359 }
360 else
361 {
362 if (flex_date)
363 {
364 struct timespec now;
365 gettime (&now);
366 get_reldate (&newtime[0], flex_date, &now);
367 newtime[1] = newtime[0];
368 date_set = true;
369
370 /* If neither -a nor -m is specified, treat "-d now" as if
371 it were absent; this lets "touch" succeed more often in
372 the presence of restrictive permissions. */
373 if (change_times == (CH_ATIME | CH_MTIME)
374 && newtime[0].tv_sec == now.tv_sec
375 && newtime[0].tv_nsec == now.tv_nsec)
376 {
377 /* Check that it really was "-d now", and not a timestamp
378 that just happens to be the current time. */
379 struct timespec notnow, notnow1;
380 notnow.tv_sec = now.tv_sec ^ 1;
381 notnow.tv_nsec = now.tv_nsec;
382 get_reldate (¬now1, flex_date, ¬now);
383 if (notnow1.tv_sec == notnow.tv_sec
384 && notnow1.tv_nsec == notnow.tv_nsec)
385 date_set = false;
386 }
387 }
388 }
389
390 /* The obsolete 'MMDDhhmm[YY]' form is valid IFF there are
391 two or more non-option arguments. */
392 if (!date_set && 2 <= argc - optind && posix2_version () < 200112
393 && posixtime (&newtime[0].tv_sec, argv[optind],
394 PDS_TRAILING_YEAR | PDS_PRE_2000))
395 {
396 newtime[0].tv_nsec = 0;
397 newtime[1] = newtime[0];
398 date_set = true;
399
400 if (! getenv ("POSIXLY_CORRECT"))
401 {
402 struct tm const *tm = localtime (&newtime[0].tv_sec);
403
404 /* Technically, it appears that even a deliberate attempt to cause
405 the above localtime to return NULL will always fail because our
406 posixtime implementation rejects all dates for which localtime
407 would fail. However, skip the warning if it ever fails. */
408 if (tm)
409 error (0, 0,
410 _("warning: 'touch %s' is obsolete; use "
411 "'touch -t %04ld%02d%02d%02d%02d.%02d'"),
412 argv[optind],
413 tm->tm_year + 1900L, tm->tm_mon + 1, tm->tm_mday,
414 tm->tm_hour, tm->tm_min, tm->tm_sec);
415 }
416
417 optind++;
418 }
419
420 if (!date_set)
421 {
422 if (change_times == (CH_ATIME | CH_MTIME))
423 amtime_now = true;
424 else
425 newtime[1].tv_nsec = newtime[0].tv_nsec = UTIME_NOW;
426 }
427
428 if (optind == argc)
429 {
430 error (0, 0, _("missing file operand"));
431 usage (EXIT_FAILURE);
432 }
433
434 for (; optind < argc; ++optind)
435 ok &= touch (argv[optind]);
436
437 return ok ? EXIT_SUCCESS : EXIT_FAILURE;
438 }
439