src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 1989-2022 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 "die.h"
  30 #include "error.h"
  31 #include "parse-datetime.h"
  32 #include "posixtm.h"
  33 #include "quote.h"
  34 #include "stat-time.h"
  35 #include "fprintftime.h"
  36
  37 /* The official name of this program (e.g., no 'g' prefix).  */
  38 #define PROGRAM_NAME "date"
  39
  40 #define AUTHORS proper_name ("David MacKenzie")
  41
  42 static bool show_date (char const *, struct timespec, timezone_t);
  43
  44 enum Time_spec
  45 {
  46   /* Display only the date.  */
  47   TIME_SPEC_DATE,
  48   /* Display date, hours, minutes, and seconds.  */
  49   TIME_SPEC_SECONDS,
  50   /* Similar, but display nanoseconds. */
  51   TIME_SPEC_NS,
  52
  53   /* Put these last, since they aren't valid for --rfc-3339.  */
  54
  55   /* Display date and hour.  */
  56   TIME_SPEC_HOURS,
  57   /* Display date, hours, and minutes.  */
  58   TIME_SPEC_MINUTES
  59 };
  60
  61 static char const *const time_spec_string[] =
  62 {
  63   /* Put "hours" and "minutes" first, since they aren't valid for
  64      --rfc-3339.  */
  65   "hours", "minutes",
  66   "date", "seconds", "ns", NULL
  67 };
  68 static enum Time_spec const time_spec[] =
  69 {
  70   TIME_SPEC_HOURS, TIME_SPEC_MINUTES,
  71   TIME_SPEC_DATE, TIME_SPEC_SECONDS, TIME_SPEC_NS
  72 };
  73 ARGMATCH_VERIFY (time_spec_string, time_spec);
  74
  75 /* A format suitable for Internet RFCs 5322, 2822, and 822.  */
  76 static char const rfc_email_format[] = "%a, %d %b %Y %H:%M:%S %z";
  77
  78 /* For long options that have no equivalent short option, use a
  79    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  80 enum
  81 {
  82   DEBUG_DATE_PARSING_OPTION = CHAR_MAX + 1,
  83   RESOLUTION_OPTION,
  84   RFC_3339_OPTION
  85 };
  86
  87 static char const short_options[] = "d:f:I::r:Rs:u";
  88
  89 static struct option const long_options[] =
  90 {
  91   {"date", required_argument, NULL, 'd'},
  92   {"debug", no_argument, NULL, DEBUG_DATE_PARSING_OPTION},
  93   {"file", required_argument, NULL, 'f'},
  94   {"iso-8601", optional_argument, NULL, 'I'},
  95   {"reference", required_argument, NULL, 'r'},
  96   {"resolution", no_argument, NULL, RESOLUTION_OPTION},
  97   {"rfc-email", no_argument, NULL, 'R'},
  98   {"rfc-822", no_argument, NULL, 'R'},
  99   {"rfc-2822", no_argument, NULL, 'R'},
 100   {"rfc-3339", required_argument, NULL, RFC_3339_OPTION},
 101   {"set", required_argument, NULL, 's'},
 102   {"uct", no_argument, NULL, 'u'},
 103   {"utc", no_argument, NULL, 'u'},
 104   {"universal", no_argument, NULL, 'u'},
 105   {GETOPT_HELP_OPTION_DECL},
 106   {GETOPT_VERSION_OPTION_DECL},
 107   {NULL, 0, NULL, 0}
 108 };
 109
 110 /* flags for parse_datetime2 */
 111 static unsigned int parse_datetime_flags;
 112
 113 #if LOCALTIME_CACHE
 114 # define TZSET tzset ()
 115 #else
 116 # define TZSET /* empty */
 117 #endif
 118
 119 #ifdef _DATE_FMT
 120 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
 121 #else
 122 # define DATE_FMT_LANGINFO() ""
 123 #endif
 124
 125 void
 126 usage (int status)
 127 {
 128   if (status != EXIT_SUCCESS)
 129     emit_try_help ();
 130   else
 131     {
 132       printf (_("\
 133 Usage: %s [OPTION]... [+FORMAT]\n\
 134   or:  %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
 135 "),
 136               program_name, program_name);
 137       fputs (_("\
 138 Display date and time in the given FORMAT.\n\
 139 With -s, or with [MMDDhhmm[[CC]YY][.ss]], set the date and time.\n\
 140 "), stdout);
 141
 142       emit_mandatory_arg_note ();
 143
 144       fputs (_("\
 145   -d, --date=STRING          display time described by STRING, not 'now'\n\
 146 "), stdout);
 147       fputs (_("\
 148       --debug                annotate the parsed date,\n\
 149                               and warn about questionable usage to stderr\n\
 150 "), stdout);
 151       fputs (_("\
 152   -f, --file=DATEFILE        like --date; once for each line of DATEFILE\n\
 153 "), stdout);
 154       fputs (_("\
 155   -I[FMT], --iso-8601[=FMT]  output date/time in ISO 8601 format.\n\
 156                                FMT='date' for date only (the default),\n\
 157                                'hours', 'minutes', 'seconds', or 'ns'\n\
 158                                for date and time to the indicated precision.\n\
 159                                Example: 2006-08-14T02:34:56-06:00\n\
 160 "), stdout);
 161       fputs (_("\
 162   --resolution               output the available resolution of timestamps\n\
 163                                Example: 0.000000001\n\
 164 "), stdout);
 165       fputs (_("\
 166   -R, --rfc-email            output date and time in RFC 5322 format.\n\
 167                                Example: Mon, 14 Aug 2006 02:34:56 -0600\n\
 168 "), stdout);
 169       fputs (_("\
 170       --rfc-3339=FMT         output date/time in RFC 3339 format.\n\
 171                                FMT='date', 'seconds', or 'ns'\n\
 172                                for date and time to the indicated precision.\n\
 173                                Example: 2006-08-14 02:34:56-06:00\n\
 174 "), stdout);
 175       fputs (_("\
 176   -r, --reference=FILE       display the last modification time of FILE\n\
 177 "), stdout);
 178       fputs (_("\
 179   -s, --set=STRING           set time described by STRING\n\
 180   -u, --utc, --universal     print or set Coordinated Universal Time (UTC)\n\
 181 "), stdout);
 182       fputs (HELP_OPTION_DESCRIPTION, stdout);
 183       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 184       fputs (_("\
 185 \n\
 186 FORMAT controls the output.  Interpreted sequences are:\n\
 187 \n\
 188   %%   a literal %\n\
 189   %a   locale's abbreviated weekday name (e.g., Sun)\n\
 190 "), stdout);
 191       fputs (_("\
 192   %A   locale's full weekday name (e.g., Sunday)\n\
 193   %b   locale's abbreviated month name (e.g., Jan)\n\
 194   %B   locale's full month name (e.g., January)\n\
 195   %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)\n\
 196 "), stdout);
 197       fputs (_("\
 198   %C   century; like %Y, except omit last two digits (e.g., 20)\n\
 199   %d   day of month (e.g., 01)\n\
 200   %D   date; same as %m/%d/%y\n\
 201   %e   day of month, space padded; same as %_d\n\
 202 "), stdout);
 203       fputs (_("\
 204   %F   full date; like %+4Y-%m-%d\n\
 205   %g   last two digits of year of ISO week number (see %G)\n\
 206   %G   year of ISO week number (see %V); normally useful only with %V\n\
 207 "), stdout);
 208       fputs (_("\
 209   %h   same as %b\n\
 210   %H   hour (00..23)\n\
 211   %I   hour (01..12)\n\
 212   %j   day of year (001..366)\n\
 213 "), stdout);
 214       fputs (_("\
 215   %k   hour, space padded ( 0..23); same as %_H\n\
 216   %l   hour, space padded ( 1..12); same as %_I\n\
 217   %m   month (01..12)\n\
 218   %M   minute (00..59)\n\
 219 "), stdout);
 220       fputs (_("\
 221   %n   a newline\n\
 222   %N   nanoseconds (000000000..999999999)\n\
 223   %p   locale's equivalent of either AM or PM; blank if not known\n\
 224   %P   like %p, but lower case\n\
 225   %q   quarter of year (1..4)\n\
 226   %r   locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
 227   %R   24-hour hour and minute; same as %H:%M\n\
 228   %s   seconds since the Epoch (1970-01-01 00:00 UTC)\n\
 229 "), stdout);
 230       fputs (_("\
 231   %S   second (00..60)\n\
 232   %t   a tab\n\
 233   %T   time; same as %H:%M:%S\n\
 234   %u   day of week (1..7); 1 is Monday\n\
 235 "), stdout);
 236       fputs (_("\
 237   %U   week number of year, with Sunday as first day of week (00..53)\n\
 238   %V   ISO week number, with Monday as first day of week (01..53)\n\
 239   %w   day of week (0..6); 0 is Sunday\n\
 240   %W   week number of year, with Monday as first day of week (00..53)\n\
 241 "), stdout);
 242       fputs (_("\
 243   %x   locale's date representation (e.g., 12/31/99)\n\
 244   %X   locale's time representation (e.g., 23:13:48)\n\
 245   %y   last two digits of year (00..99)\n\
 246   %Y   year\n\
 247 "), stdout);
 248       fputs (_("\
 249   %z   +hhmm numeric time zone (e.g., -0400)\n\
 250   %:z  +hh:mm numeric time zone (e.g., -04:00)\n\
 251   %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
 252   %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
 253   %Z   alphabetic time zone abbreviation (e.g., EDT)\n\
 254 \n\
 255 By default, date pads numeric fields with zeroes.\n\
 256 "), stdout);
 257       fputs (_("\
 258 The following optional flags may follow '%':\n\
 259 \n\
 260   -  (hyphen) do not pad the field\n\
 261   _  (underscore) pad with spaces\n\
 262   0  (zero) pad with zeros\n\
 263   +  pad with zeros, and put '+' before future years with >4 digits\n\
 264   ^  use upper case if possible\n\
 265   #  use opposite case if possible\n\
 266 "), stdout);
 267       fputs (_("\
 268 \n\
 269 After any flags comes an optional field width, as a decimal number;\n\
 270 then an optional modifier, which is either\n\
 271 E to use the locale's alternate representations if available, or\n\
 272 O to use the locale's alternate numeric symbols if available.\n\
 273 "), stdout);
 274       fputs (_("\
 275 \n\
 276 Examples:\n\
 277 Convert seconds since the Epoch (1970-01-01 UTC) to a date\n\
 278   $ date --date='@2147483647'\n\
 279 \n\
 280 Show the time on the west coast of the US (use tzselect(1) to find TZ)\n\
 281   $ TZ='America/Los_Angeles' date\n\
 282 \n\
 283 Show the local time for 9AM next Friday on the west coast of the US\n\
 284   $ date --date='TZ=\"America/Los_Angeles\" 09:00 next Fri'\n\
 285 "), stdout);
 286       emit_ancillary_info (PROGRAM_NAME);
 287     }
 288   exit (status);
 289 }
 290
 291 /* Yield the number of decimal digits needed to output a time with the
 292    nanosecond resolution RES, without losing information.  */
 293
 294 static int
 295 res_width (long int res)
 296 {
 297   int i = 9;
 298   for (long long int r = 1; (r *= 10) <= res; )
 299     i--;
 300   return i;
 301 }
 302
 303 /* Return a newly allocated copy of FORMAT with each "%-N" adjusted to
 304    be "%9N", "%6N", or whatever other resolution is appropriate for
 305    the current platform.  If no "%-N" appears, return NULL.  */
 306
 307 static char *
 308 adjust_resolution (char const *format)
 309 {
 310   char *copy = NULL;
 311
 312   for (char const *f = format; *f; f++)
 313     if (f[0] == '%')
 314       {
 315         if (f[1] == '-' && f[2] == 'N')
 316           {
 317             if (!copy)
 318               copy = xstrdup (format);
 319             copy[f + 1 - format] = '0' + res_width (gettime_res ());
 320             f += 2;
 321           }
 322         else
 323           f += f[1] == '%';
 324       }
 325
 326   return copy;
 327 }
 328
 329 /* Parse each line in INPUT_FILENAME as with --date and display each
 330    resulting time and date.  If the file cannot be opened, tell why
 331    then exit.  Issue a diagnostic for any lines that cannot be parsed.
 332    Return true if successful.  */
 333
 334 static bool
 335 batch_convert (char const *input_filename, char const *format,
 336                timezone_t tz, char const *tzstring)
 337 {
 338   bool ok;
 339   FILE *in_stream;
 340   char *line;
 341   size_t buflen;
 342   struct timespec when;
 343
 344   if (STREQ (input_filename, "-"))
 345     {
 346       input_filename = _("standard input");
 347       in_stream = stdin;
 348     }
 349   else
 350     {
 351       in_stream = fopen (input_filename, "r");
 352       if (in_stream == NULL)
 353         {
 354           die (EXIT_FAILURE, errno, "%s", quotef (input_filename));
 355         }
 356     }
 357
 358   line = NULL;
 359   buflen = 0;
 360   ok = true;
 361   while (true)
 362     {
 363       ssize_t line_length = getline (&line, &buflen, in_stream);
 364       if (line_length < 0)
 365         {
 366           /* FIXME: detect/handle error here.  */
 367           break;
 368         }
 369
 370       if (! parse_datetime2 (&when, line, NULL,
 371                              parse_datetime_flags, tz, tzstring))
 372         {
 373           if (line[line_length - 1] == '\n')
 374             line[line_length - 1] = '\0';
 375           error (0, 0, _("invalid date %s"), quote (line));
 376           ok = false;
 377         }
 378       else
 379         {
 380           ok &= show_date (format, when, tz);
 381         }
 382     }
 383
 384   if (fclose (in_stream) == EOF)
 385     die (EXIT_FAILURE, errno, "%s", quotef (input_filename));
 386
 387   free (line);
 388
 389   return ok;
 390 }
 391
 392 int
 393 main (int argc, char **argv)
 394 {
 395   int optc;
 396   char const *datestr = NULL;
 397   char const *set_datestr = NULL;
 398   struct timespec when;
 399   bool set_date = false;
 400   char const *format = NULL;
 401   bool get_resolution = false;
 402   char *batch_file = NULL;
 403   char *reference = NULL;
 404   struct stat refstats;
 405   bool ok;
 406
 407   initialize_main (&argc, &argv);
 408   set_program_name (argv[0]);
 409   setlocale (LC_ALL, "");
 410   bindtextdomain (PACKAGE, LOCALEDIR);
 411   textdomain (PACKAGE);
 412
 413   atexit (close_stdout);
 414
 415   while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
 416          != -1)
 417     {
 418       char const *new_format = NULL;
 419
 420       switch (optc)
 421         {
 422         case 'd':
 423           datestr = optarg;
 424           break;
 425         case DEBUG_DATE_PARSING_OPTION:
 426           parse_datetime_flags |= PARSE_DATETIME_DEBUG;
 427           break;
 428         case 'f':
 429           batch_file = optarg;
 430           break;
 431         case RESOLUTION_OPTION:
 432           get_resolution = true;
 433           break;
 434         case RFC_3339_OPTION:
 435           {
 436             static char const rfc_3339_format[][32] =
 437               {
 438                 "%Y-%m-%d",
 439                 "%Y-%m-%d %H:%M:%S%:z",
 440                 "%Y-%m-%d %H:%M:%S.%N%:z"
 441               };
 442             enum Time_spec i =
 443               XARGMATCH ("--rfc-3339", optarg,
 444                          time_spec_string + 2, time_spec + 2);
 445             new_format = rfc_3339_format[i];
 446             break;
 447           }
 448         case 'I':
 449           {
 450             static char const iso_8601_format[][32] =
 451               {
 452                 "%Y-%m-%d",
 453                 "%Y-%m-%dT%H:%M:%S%:z",
 454                 "%Y-%m-%dT%H:%M:%S,%N%:z",
 455                 "%Y-%m-%dT%H%:z",
 456                 "%Y-%m-%dT%H:%M%:z"
 457               };
 458             enum Time_spec i =
 459               (optarg
 460                ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
 461                : TIME_SPEC_DATE);
 462             new_format = iso_8601_format[i];
 463             break;
 464           }
 465         case 'r':
 466           reference = optarg;
 467           break;
 468         case 'R':
 469           new_format = rfc_email_format;
 470           break;
 471         case 's':
 472           set_datestr = optarg;
 473           set_date = true;
 474           break;
 475         case 'u':
 476           /* POSIX says that 'date -u' is equivalent to setting the TZ
 477              environment variable, so this option should do nothing other
 478              than setting TZ.  */
 479           if (putenv (bad_cast ("TZ=UTC0")) != 0)
 480             xalloc_die ();
 481           TZSET;
 482           break;
 483         case_GETOPT_HELP_CHAR;
 484         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 485         default:
 486           usage (EXIT_FAILURE);
 487         }
 488
 489       if (new_format)
 490         {
 491           if (format)
 492             die (EXIT_FAILURE, 0, _("multiple output formats specified"));
 493           format = new_format;
 494         }
 495     }
 496
 497   int option_specified_date = (!!datestr + !!batch_file + !!reference
 498                                + get_resolution);
 499
 500   if (option_specified_date > 1)
 501     {
 502       error (0, 0,
 503         _("the options to specify dates for printing are mutually exclusive"));
 504       usage (EXIT_FAILURE);
 505     }
 506
 507   if (set_date && option_specified_date)
 508     {
 509       error (0, 0,
 510           _("the options to print and set the time may not be used together"));
 511       usage (EXIT_FAILURE);
 512     }
 513
 514   if (optind < argc)
 515     {
 516       if (optind + 1 < argc)
 517         {
 518           error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 519           usage (EXIT_FAILURE);
 520         }
 521
 522       if (argv[optind][0] == '+')
 523         {
 524           if (format)
 525             die (EXIT_FAILURE, 0, _("multiple output formats specified"));
 526           format = argv[optind++] + 1;
 527         }
 528       else if (set_date || option_specified_date)
 529         {
 530           error (0, 0,
 531                  _("the argument %s lacks a leading '+';\n"
 532                    "when using an option to specify date(s), any non-option\n"
 533                    "argument must be a format string beginning with '+'"),
 534                  quote (argv[optind]));
 535           usage (EXIT_FAILURE);
 536         }
 537     }
 538
 539   if (!format)
 540     {
 541       if (get_resolution)
 542         format = "%s.%N";
 543       else
 544         {
 545           format = DATE_FMT_LANGINFO ();
 546
 547           /* Do not wrap the following literal format string with _(...).
 548              For example, suppose LC_ALL is unset, LC_TIME=POSIX,
 549              and LANG="ko_KR".  In that case, POSIX says that LC_TIME
 550              determines the format and contents of date and time strings
 551              written by date, which means "date" must generate output
 552              using the POSIX locale; but adding _() would cause "date"
 553              to use a Korean translation of the format.  */
 554           if (! *format)
 555             format = "%a %b %e %H:%M:%S %Z %Y";
 556         }
 557     }
 558
 559   char *format_copy = adjust_resolution (format);
 560   char const *format_res = format_copy ? format_copy : format;
 561   char const *tzstring = getenv ("TZ");
 562   timezone_t tz = tzalloc (tzstring);
 563
 564   if (batch_file != NULL)
 565     ok = batch_convert (batch_file, format_res, tz, tzstring);
 566   else
 567     {
 568       bool valid_date = true;
 569       ok = true;
 570
 571       if (!option_specified_date && !set_date)
 572         {
 573           if (optind < argc)
 574             {
 575               /* Prepare to set system clock to the specified date/time
 576                  given in the POSIX-format.  */
 577               set_date = true;
 578               datestr = argv[optind];
 579               valid_date = posixtime (&when.tv_sec,
 580                                       datestr,
 581                                       (PDS_TRAILING_YEAR
 582                                        | PDS_CENTURY | PDS_SECONDS));
 583               when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
 584             }
 585           else
 586             {
 587               /* Prepare to print the current date/time.  */
 588               gettime (&when);
 589             }
 590         }
 591       else
 592         {
 593           /* (option_specified_date || set_date) */
 594           if (reference != NULL)
 595             {
 596               if (stat (reference, &refstats) != 0)
 597                 die (EXIT_FAILURE, errno, "%s", quotef (reference));
 598               when = get_stat_mtime (&refstats);
 599             }
 600           else if (get_resolution)
 601             {
 602               long int res = gettime_res ();
 603               when.tv_sec = res / TIMESPEC_HZ;
 604               when.tv_nsec = res % TIMESPEC_HZ;
 605             }
 606           else
 607             {
 608               if (set_datestr)
 609                 datestr = set_datestr;
 610               valid_date = parse_datetime2 (&when, datestr, NULL,
 611                                             parse_datetime_flags,
 612                                             tz, tzstring);
 613             }
 614         }
 615
 616       if (! valid_date)
 617         die (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
 618
 619       if (set_date)
 620         {
 621           /* Set the system clock to the specified date, then regardless of
 622              the success of that operation, format and print that date.  */
 623           if (settime (&when) != 0)
 624             {
 625               error (0, errno, _("cannot set date"));
 626               ok = false;
 627             }
 628         }
 629
 630       ok &= show_date (format_res, when, tz);
 631     }
 632
 633   main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 634 }
 635
 636 /* Display the date and/or time in WHEN according to the format specified
 637    in FORMAT, followed by a newline.  Return true if successful.  */
 638
 639 static bool
 640 show_date (char const *format, struct timespec when, timezone_t tz)
 641 {
 642   struct tm tm;
 643
 644   if (parse_datetime_flags & PARSE_DATETIME_DEBUG)
 645     error (0, 0, _("output format: %s"), quote (format));
 646
 647   if (localtime_rz (tz, &when.tv_sec, &tm))
 648     {
 649       if (format == rfc_email_format)
 650         setlocale (LC_TIME, "C");
 651       fprintftime (stdout, format, &tm, tz, when.tv_nsec);
 652       if (format == rfc_email_format)
 653         setlocale (LC_TIME, "");
 654       fputc ('\n', stdout);
 655       return true;
 656     }
 657   else
 658     {
 659       char buf[INT_BUFSIZE_BOUND (intmax_t)];
 660       error (0, 0, _("time %s is out of range"),
 661              quote (timetostr (when.tv_sec, buf)));
 662       return false;
 663     }
 664 }