1 /* date - print or set the system date and time
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 David MacKenzie <djm@gnu.ai.mit.edu> */
18
19 #include <config.h>
20 #include <stdio.h>
21 #include <getopt.h>
22 #include <sys/types.h>
23 #if HAVE_LANGINFO_CODESET
24 # include <langinfo.h>
25 #endif
26
27 #include "system.h"
28 #include "argmatch.h"
29 #include "parse-datetime.h"
30 #include "posixtm.h"
31 #include "quote.h"
32 #include "stat-time.h"
33 #include "fprintftime.h"
34
35 /* The official name of this program (e.g., no 'g' prefix). */
36 #define PROGRAM_NAME "date"
37
38 #define AUTHORS proper_name ("David MacKenzie")
39
40 static bool show_date (char const *, struct timespec, timezone_t);
41
42 enum Time_spec
43 {
44 /* Display only the date. */
45 TIME_SPEC_DATE,
46 /* Display date, hours, minutes, and seconds. */
47 TIME_SPEC_SECONDS,
48 /* Similar, but display nanoseconds. */
49 TIME_SPEC_NS,
50
51 /* Put these last, since they aren't valid for --rfc-3339. */
52
53 /* Display date and hour. */
54 TIME_SPEC_HOURS,
55 /* Display date, hours, and minutes. */
56 TIME_SPEC_MINUTES
57 };
58
59 static char const *const time_spec_string[] =
60 {
61 /* Put "hours" and "minutes" first, since they aren't valid for
62 --rfc-3339. */
63 "hours", "minutes",
64 "date", "seconds", "ns", nullptr
65 };
66 static enum Time_spec const time_spec[] =
67 {
68 TIME_SPEC_HOURS, TIME_SPEC_MINUTES,
69 TIME_SPEC_DATE, TIME_SPEC_SECONDS, TIME_SPEC_NS
70 };
71 ARGMATCH_VERIFY (time_spec_string, time_spec);
72
73 /* A format suitable for Internet RFCs 5322, 2822, and 822. */
74 static char const rfc_email_format[] = "%a, %d %b %Y %H:%M:%S %z";
75
76 /* For long options that have no equivalent short option, use a
77 non-character as a pseudo short option, starting with CHAR_MAX + 1. */
78 enum
79 {
80 DEBUG_DATE_PARSING_OPTION = CHAR_MAX + 1,
81 RESOLUTION_OPTION,
82 RFC_3339_OPTION
83 };
84
85 static char const short_options[] = "d:f:I::r:Rs:u";
86
87 static struct option const long_options[] =
88 {
89 {"date", required_argument, nullptr, 'd'},
90 {"debug", no_argument, nullptr, DEBUG_DATE_PARSING_OPTION},
91 {"file", required_argument, nullptr, 'f'},
92 {"iso-8601", optional_argument, nullptr, 'I'},
93 {"reference", required_argument, nullptr, 'r'},
94 {"resolution", no_argument, nullptr, RESOLUTION_OPTION},
95 {"rfc-email", no_argument, nullptr, 'R'},
96 {"rfc-822", no_argument, nullptr, 'R'},
97 {"rfc-2822", no_argument, nullptr, 'R'},
98 {"rfc-3339", required_argument, nullptr, RFC_3339_OPTION},
99 {"set", required_argument, nullptr, 's'},
100 {"uct", no_argument, nullptr, 'u'},
101 {"utc", no_argument, nullptr, 'u'},
102 {"universal", no_argument, nullptr, 'u'},
103 {GETOPT_HELP_OPTION_DECL},
104 {GETOPT_VERSION_OPTION_DECL},
105 {nullptr, 0, nullptr, 0}
106 };
107
108 /* flags for parse_datetime2 */
109 static unsigned int parse_datetime_flags;
110
111 #if LOCALTIME_CACHE
112 # define TZSET tzset ()
113 #else
114 # define TZSET /* empty */
115 #endif
116
117 #ifdef _DATE_FMT
118 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
119 #else
120 # define DATE_FMT_LANGINFO() ""
121 #endif
122
123 void
usage(int status)124 usage (int status)
125 {
126 if (status != EXIT_SUCCESS)
127 emit_try_help ();
128 else
129 {
130 printf (_("\
131 Usage: %s [OPTION]... [+FORMAT]\n\
132 or: %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
133 "),
134 program_name, program_name);
135 fputs (_("\
136 Display date and time in the given FORMAT.\n\
137 With -s, or with [MMDDhhmm[[CC]YY][.ss]], set the date and time.\n\
138 "), stdout);
139
140 emit_mandatory_arg_note ();
141
142 fputs (_("\
143 -d, --date=STRING display time described by STRING, not 'now'\n\
144 "), stdout);
145 fputs (_("\
146 --debug annotate the parsed date,\n\
147 and warn about questionable usage to stderr\n\
148 "), stdout);
149 fputs (_("\
150 -f, --file=DATEFILE like --date; once for each line of DATEFILE\n\
151 "), stdout);
152 fputs (_("\
153 -I[FMT], --iso-8601[=FMT] output date/time in ISO 8601 format.\n\
154 FMT='date' for date only (the default),\n\
155 'hours', 'minutes', 'seconds', or 'ns'\n\
156 for date and time to the indicated precision.\n\
157 Example: 2006-08-14T02:34:56-06:00\n\
158 "), stdout);
159 fputs (_("\
160 --resolution output the available resolution of timestamps\n\
161 Example: 0.000000001\n\
162 "), stdout);
163 fputs (_("\
164 -R, --rfc-email output date and time in RFC 5322 format.\n\
165 Example: Mon, 14 Aug 2006 02:34:56 -0600\n\
166 "), stdout);
167 fputs (_("\
168 --rfc-3339=FMT output date/time in RFC 3339 format.\n\
169 FMT='date', 'seconds', or 'ns'\n\
170 for date and time to the indicated precision.\n\
171 Example: 2006-08-14 02:34:56-06:00\n\
172 "), stdout);
173 fputs (_("\
174 -r, --reference=FILE display the last modification time of FILE\n\
175 "), stdout);
176 fputs (_("\
177 -s, --set=STRING set time described by STRING\n\
178 -u, --utc, --universal print or set Coordinated Universal Time (UTC)\n\
179 "), stdout);
180 fputs (HELP_OPTION_DESCRIPTION, stdout);
181 fputs (VERSION_OPTION_DESCRIPTION, stdout);
182 fputs (_("\
183 \n\
184 All options that specify the date to display are mutually exclusive.\n\
185 I.e.: --date, --file, --reference, --resolution.\n\
186 "), stdout);
187 fputs (_("\
188 \n\
189 FORMAT controls the output. Interpreted sequences are:\n\
190 \n\
191 %% a literal %\n\
192 %a locale's abbreviated weekday name (e.g., Sun)\n\
193 "), stdout);
194 fputs (_("\
195 %A locale's full weekday name (e.g., Sunday)\n\
196 %b locale's abbreviated month name (e.g., Jan)\n\
197 %B locale's full month name (e.g., January)\n\
198 %c locale's date and time (e.g., Thu Mar 3 23:05:25 2005)\n\
199 "), stdout);
200 fputs (_("\
201 %C century; like %Y, except omit last two digits (e.g., 20)\n\
202 %d day of month (e.g., 01)\n\
203 %D date; same as %m/%d/%y\n\
204 %e day of month, space padded; same as %_d\n\
205 "), stdout);
206 fputs (_("\
207 %F full date; like %+4Y-%m-%d\n\
208 %g last two digits of year of ISO week number (see %G)\n\
209 %G year of ISO week number (see %V); normally useful only with %V\n\
210 "), stdout);
211 fputs (_("\
212 %h same as %b\n\
213 %H hour (00..23)\n\
214 %I hour (01..12)\n\
215 %j day of year (001..366)\n\
216 "), stdout);
217 fputs (_("\
218 %k hour, space padded ( 0..23); same as %_H\n\
219 %l hour, space padded ( 1..12); same as %_I\n\
220 %m month (01..12)\n\
221 %M minute (00..59)\n\
222 "), stdout);
223 fputs (_("\
224 %n a newline\n\
225 %N nanoseconds (000000000..999999999)\n\
226 %p locale's equivalent of either AM or PM; blank if not known\n\
227 %P like %p, but lower case\n\
228 %q quarter of year (1..4)\n\
229 %r locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
230 %R 24-hour hour and minute; same as %H:%M\n\
231 %s seconds since the Epoch (1970-01-01 00:00 UTC)\n\
232 "), stdout);
233 fputs (_("\
234 %S second (00..60)\n\
235 %t a tab\n\
236 %T time; same as %H:%M:%S\n\
237 %u day of week (1..7); 1 is Monday\n\
238 "), stdout);
239 fputs (_("\
240 %U week number of year, with Sunday as first day of week (00..53)\n\
241 %V ISO week number, with Monday as first day of week (01..53)\n\
242 %w day of week (0..6); 0 is Sunday\n\
243 %W week number of year, with Monday as first day of week (00..53)\n\
244 "), stdout);
245 fputs (_("\
246 %x locale's date representation (e.g., 12/31/99)\n\
247 %X locale's time representation (e.g., 23:13:48)\n\
248 %y last two digits of year (00..99)\n\
249 %Y year\n\
250 "), stdout);
251 fputs (_("\
252 %z +hhmm numeric time zone (e.g., -0400)\n\
253 %:z +hh:mm numeric time zone (e.g., -04:00)\n\
254 %::z +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
255 %:::z numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
256 %Z alphabetic time zone abbreviation (e.g., EDT)\n\
257 \n\
258 By default, date pads numeric fields with zeroes.\n\
259 "), stdout);
260 fputs (_("\
261 The following optional flags may follow '%':\n\
262 \n\
263 - (hyphen) do not pad the field\n\
264 _ (underscore) pad with spaces\n\
265 0 (zero) pad with zeros\n\
266 + pad with zeros, and put '+' before future years with >4 digits\n\
267 ^ use upper case if possible\n\
268 # use opposite case if possible\n\
269 "), stdout);
270 fputs (_("\
271 \n\
272 After any flags comes an optional field width, as a decimal number;\n\
273 then an optional modifier, which is either\n\
274 E to use the locale's alternate representations if available, or\n\
275 O to use the locale's alternate numeric symbols if available.\n\
276 "), stdout);
277 fputs (_("\
278 \n\
279 Examples:\n\
280 Convert seconds since the Epoch (1970-01-01 UTC) to a date\n\
281 $ date --date='@2147483647'\n\
282 \n\
283 Show the time on the west coast of the US (use tzselect(1) to find TZ)\n\
284 $ TZ='America/Los_Angeles' date\n\
285 \n\
286 Show the local time for 9AM next Friday on the west coast of the US\n\
287 $ date --date='TZ=\"America/Los_Angeles\" 09:00 next Fri'\n\
288 "), stdout);
289 emit_ancillary_info (PROGRAM_NAME);
290 }
291 exit (status);
292 }
293
294 /* Yield the number of decimal digits needed to output a time with the
295 nanosecond resolution RES, without losing information. */
296
297 static int
res_width(long int res)298 res_width (long int res)
299 {
300 int i = 9;
301 for (long long int r = 1; (r *= 10) <= res; )
302 i--;
303 return i;
304 }
305
306 /* Return a newly allocated copy of FORMAT with each "%-N" adjusted to
307 be "%9N", "%6N", or whatever other resolution is appropriate for
308 the current platform. If no "%-N" appears, return nullptr. */
309
310 static char *
adjust_resolution(char const * format)311 adjust_resolution (char const *format)
312 {
313 char *copy = nullptr;
314
315 for (char const *f = format; *f; f++)
316 if (f[0] == '%')
317 {
318 if (f[1] == '-' && f[2] == 'N')
319 {
320 if (!copy)
321 copy = xstrdup (format);
322 copy[f + 1 - format] = '0' + res_width (gettime_res ());
323 f += 2;
324 }
325 else
326 f += f[1] == '%';
327 }
328
329 return copy;
330 }
331
332 /* Parse each line in INPUT_FILENAME as with --date and display each
333 resulting time and date. If the file cannot be opened, tell why
334 then exit. Issue a diagnostic for any lines that cannot be parsed.
335 Return true if successful. */
336
337 static bool
batch_convert(char const * input_filename,char const * format,timezone_t tz,char const * tzstring)338 batch_convert (char const *input_filename, char const *format,
339 timezone_t tz, char const *tzstring)
340 {
341 bool ok;
342 FILE *in_stream;
343 char *line;
344 size_t buflen;
345 struct timespec when;
346
347 if (STREQ (input_filename, "-"))
348 {
349 input_filename = _("standard input");
350 in_stream = stdin;
351 }
352 else
353 {
354 in_stream = fopen (input_filename, "r");
355 if (in_stream == nullptr)
356 error (EXIT_FAILURE, errno, "%s", quotef (input_filename));
357 }
358
359 line = nullptr;
360 buflen = 0;
361 ok = true;
362 while (true)
363 {
364 ssize_t line_length = getline (&line, &buflen, in_stream);
365 if (line_length < 0)
366 {
367 if (ferror (in_stream))
368 error (EXIT_FAILURE, errno, _("%s: read error"),
369 quotef (input_filename));
370 break;
371 }
372
373 if (! parse_datetime2 (&when, line, nullptr,
374 parse_datetime_flags, tz, tzstring))
375 {
376 if (line[line_length - 1] == '\n')
377 line[line_length - 1] = '\0';
378 error (0, 0, _("invalid date %s"), quote (line));
379 ok = false;
380 }
381 else
382 {
383 ok &= show_date (format, when, tz);
384 }
385 }
386
387 if (fclose (in_stream) == EOF)
388 error (EXIT_FAILURE, errno, "%s", quotef (input_filename));
389
390 free (line);
391
392 return ok;
393 }
394
395 int
main(int argc,char ** argv)396 main (int argc, char **argv)
397 {
398 int optc;
399 char const *datestr = nullptr;
400 char const *set_datestr = nullptr;
401 struct timespec when;
402 bool set_date = false;
403 char const *format = nullptr;
404 bool get_resolution = false;
405 char *batch_file = nullptr;
406 char *reference = nullptr;
407 struct stat refstats;
408 bool ok;
409 bool discarded_datestr = false;
410 bool discarded_set_datestr = false;
411
412 initialize_main (&argc, &argv);
413 set_program_name (argv[0]);
414 setlocale (LC_ALL, "");
415 bindtextdomain (PACKAGE, LOCALEDIR);
416 textdomain (PACKAGE);
417
418 atexit (close_stdout);
419
420 while ((optc = getopt_long (argc, argv, short_options, long_options, nullptr))
421 != -1)
422 {
423 char const *new_format = nullptr;
424
425 switch (optc)
426 {
427 case 'd':
428 if (datestr)
429 discarded_datestr = true;
430 datestr = optarg;
431 break;
432 case DEBUG_DATE_PARSING_OPTION:
433 parse_datetime_flags |= PARSE_DATETIME_DEBUG;
434 break;
435 case 'f':
436 batch_file = optarg;
437 break;
438 case RESOLUTION_OPTION:
439 get_resolution = true;
440 break;
441 case RFC_3339_OPTION:
442 {
443 static char const rfc_3339_format[][32] =
444 {
445 "%Y-%m-%d",
446 "%Y-%m-%d %H:%M:%S%:z",
447 "%Y-%m-%d %H:%M:%S.%N%:z"
448 };
449 enum Time_spec i =
450 XARGMATCH ("--rfc-3339", optarg,
451 time_spec_string + 2, time_spec + 2);
452 new_format = rfc_3339_format[i];
453 break;
454 }
455 case 'I':
456 {
457 static char const iso_8601_format[][32] =
458 {
459 "%Y-%m-%d",
460 "%Y-%m-%dT%H:%M:%S%:z",
461 "%Y-%m-%dT%H:%M:%S,%N%:z",
462 "%Y-%m-%dT%H%:z",
463 "%Y-%m-%dT%H:%M%:z"
464 };
465 enum Time_spec i =
466 (optarg
467 ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
468 : TIME_SPEC_DATE);
469 new_format = iso_8601_format[i];
470 break;
471 }
472 case 'r':
473 reference = optarg;
474 break;
475 case 'R':
476 new_format = rfc_email_format;
477 break;
478 case 's':
479 if (set_datestr)
480 discarded_set_datestr = true;
481 set_datestr = optarg;
482 set_date = true;
483 break;
484 case 'u':
485 /* POSIX says that 'date -u' is equivalent to setting the TZ
486 environment variable, so this option should do nothing other
487 than setting TZ. */
488 if (putenv (bad_cast ("TZ=UTC0")) != 0)
489 xalloc_die ();
490 TZSET;
491 break;
492 case_GETOPT_HELP_CHAR;
493 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
494 default:
495 usage (EXIT_FAILURE);
496 }
497
498 if (new_format)
499 {
500 if (format)
501 error (EXIT_FAILURE, 0, _("multiple output formats specified"));
502 format = new_format;
503 }
504 }
505
506 int option_specified_date = (!!datestr + !!batch_file + !!reference
507 + get_resolution);
508
509 if (option_specified_date > 1)
510 {
511 error (0, 0,
512 _("the options to specify dates for printing are mutually exclusive"));
513 usage (EXIT_FAILURE);
514 }
515
516 if (set_date && option_specified_date)
517 {
518 error (0, 0,
519 _("the options to print and set the time may not be used together"));
520 usage (EXIT_FAILURE);
521 }
522
523 if (discarded_datestr && (parse_datetime_flags & PARSE_DATETIME_DEBUG))
524 error (0, 0, _("only using last of multiple -d options"));
525
526 if (discarded_set_datestr && (parse_datetime_flags & PARSE_DATETIME_DEBUG))
527 error (0, 0, _("only using last of multiple -s options"));
528
529 if (optind < argc)
530 {
531 if (optind + 1 < argc)
532 {
533 error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
534 usage (EXIT_FAILURE);
535 }
536
537 if (argv[optind][0] == '+')
538 {
539 if (format)
540 error (EXIT_FAILURE, 0, _("multiple output formats specified"));
541 format = argv[optind++] + 1;
542 }
543 else if (set_date || option_specified_date)
544 {
545 error (0, 0,
546 _("the argument %s lacks a leading '+';\n"
547 "when using an option to specify date(s), any non-option\n"
548 "argument must be a format string beginning with '+'"),
549 quote (argv[optind]));
550 usage (EXIT_FAILURE);
551 }
552 }
553
554 if (!format)
555 {
556 if (get_resolution)
557 format = "%s.%N";
558 else
559 {
560 format = DATE_FMT_LANGINFO ();
561
562 /* Do not wrap the following literal format string with _(...).
563 For example, suppose LC_ALL is unset, LC_TIME=POSIX,
564 and LANG="ko_KR". In that case, POSIX says that LC_TIME
565 determines the format and contents of date and time strings
566 written by date, which means "date" must generate output
567 using the POSIX locale; but adding _() would cause "date"
568 to use a Korean translation of the format. */
569 if (! *format)
570 format = "%a %b %e %H:%M:%S %Z %Y";
571 }
572 }
573
574 char *format_copy = adjust_resolution (format);
575 char const *format_res = format_copy ? format_copy : format;
576 char const *tzstring = getenv ("TZ");
577 timezone_t tz = tzalloc (tzstring);
578
579 if (batch_file != nullptr)
580 ok = batch_convert (batch_file, format_res, tz, tzstring);
581 else
582 {
583 bool valid_date = true;
584 ok = true;
585
586 if (!option_specified_date && !set_date)
587 {
588 if (optind < argc)
589 {
590 /* Prepare to set system clock to the specified date/time
591 given in the POSIX-format. */
592 set_date = true;
593 datestr = argv[optind];
594 valid_date = posixtime (&when.tv_sec,
595 datestr,
596 (PDS_TRAILING_YEAR
597 | PDS_CENTURY | PDS_SECONDS));
598 when.tv_nsec = 0; /* FIXME: posixtime should set this. */
599 }
600 else
601 {
602 /* Prepare to print the current date/time. */
603 gettime (&when);
604 }
605 }
606 else
607 {
608 /* (option_specified_date || set_date) */
609 if (reference != nullptr)
610 {
611 if (stat (reference, &refstats) != 0)
612 error (EXIT_FAILURE, errno, "%s", quotef (reference));
613 when = get_stat_mtime (&refstats);
614 }
615 else if (get_resolution)
616 {
617 long int res = gettime_res ();
618 when.tv_sec = res / TIMESPEC_HZ;
619 when.tv_nsec = res % TIMESPEC_HZ;
620 }
621 else
622 {
623 if (set_datestr)
624 datestr = set_datestr;
625 valid_date = parse_datetime2 (&when, datestr, nullptr,
626 parse_datetime_flags,
627 tz, tzstring);
628 }
629 }
630
631 if (! valid_date)
632 error (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
633
634 if (set_date)
635 {
636 /* Set the system clock to the specified date, then regardless of
637 the success of that operation, format and print that date. */
638 if (settime (&when) != 0)
639 {
640 error (0, errno, _("cannot set date"));
641 ok = false;
642 }
643 }
644
645 ok &= show_date (format_res, when, tz);
646 }
647
648 main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
649 }
650
651 /* Display the date and/or time in WHEN according to the format specified
652 in FORMAT, followed by a newline. Return true if successful. */
653
654 static bool
show_date(char const * format,struct timespec when,timezone_t tz)655 show_date (char const *format, struct timespec when, timezone_t tz)
656 {
657 struct tm tm;
658
659 if (parse_datetime_flags & PARSE_DATETIME_DEBUG)
660 error (0, 0, _("output format: %s"), quote (format));
661
662 if (localtime_rz (tz, &when.tv_sec, &tm))
663 {
664 if (format == rfc_email_format)
665 setlocale (LC_TIME, "C");
666 fprintftime (stdout, format, &tm, tz, when.tv_nsec);
667 if (format == rfc_email_format)
668 setlocale (LC_TIME, "");
669 fputc ('\n', stdout);
670 return true;
671 }
672 else
673 {
674 char buf[INT_BUFSIZE_BOUND (intmax_t)];
675 error (0, 0, _("time %s is out of range"),
676 quote (timetostr (when.tv_sec, buf)));
677 return false;
678 }
679 }
680