src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 1989-2012 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 <http://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 "error.h"
  30 #include "parse-datetime.h"
  31 #include "posixtm.h"
  32 #include "quote.h"
  33 #include "stat-time.h"
  34 #include "fprintftime.h"
  35
  36 /* The official name of this program (e.g., no `g' prefix).  */
  37 #define PROGRAM_NAME "date"
  38
  39 #define AUTHORS proper_name ("David MacKenzie")
  40
  41 static bool show_date (const char *format, struct timespec when);
  42
  43 enum Time_spec
  44 {
  45   /* Display only the date.  */
  46   TIME_SPEC_DATE,
  47   /* Display date, hours, minutes, and seconds.  */
  48   TIME_SPEC_SECONDS,
  49   /* Similar, but display nanoseconds. */
  50   TIME_SPEC_NS,
  51
  52   /* Put these last, since they aren't valid for --rfc-3339.  */
  53
  54   /* Display date and hour.  */
  55   TIME_SPEC_HOURS,
  56   /* Display date, hours, and minutes.  */
  57   TIME_SPEC_MINUTES
  58 };
  59
  60 static char const *const time_spec_string[] =
  61 {
  62   /* Put "hours" and "minutes" first, since they aren't valid for
  63      --rfc-3339.  */
  64   "hours", "minutes",
  65   "date", "seconds", "ns", NULL
  66 };
  67 static enum Time_spec const time_spec[] =
  68 {
  69   TIME_SPEC_HOURS, TIME_SPEC_MINUTES,
  70   TIME_SPEC_DATE, TIME_SPEC_SECONDS, TIME_SPEC_NS
  71 };
  72 ARGMATCH_VERIFY (time_spec_string, time_spec);
  73
  74 /* A format suitable for Internet RFC 2822.  */
  75 static char const rfc_2822_format[] = "%a, %d %b %Y %H:%M:%S %z";
  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   RFC_3339_OPTION = CHAR_MAX + 1
  82 };
  83
  84 static char const short_options[] = "d:f:I::r:Rs:u";
  85
  86 static struct option const long_options[] =
  87 {
  88   {"date", required_argument, NULL, 'd'},
  89   {"file", required_argument, NULL, 'f'},
  90   {"iso-8601", optional_argument, NULL, 'I'},
  91   {"reference", required_argument, NULL, 'r'},
  92   {"rfc-822", no_argument, NULL, 'R'},
  93   {"rfc-2822", no_argument, NULL, 'R'},
  94   {"rfc-3339", required_argument, NULL, RFC_3339_OPTION},
  95   {"set", required_argument, NULL, 's'},
  96   {"uct", no_argument, NULL, 'u'},
  97   {"utc", no_argument, NULL, 'u'},
  98   {"universal", no_argument, NULL, 'u'},
  99   {GETOPT_HELP_OPTION_DECL},
 100   {GETOPT_VERSION_OPTION_DECL},
 101   {NULL, 0, NULL, 0}
 102 };
 103
 104 #if LOCALTIME_CACHE
 105 # define TZSET tzset ()
 106 #else
 107 # define TZSET /* empty */
 108 #endif
 109
 110 #ifdef _DATE_FMT
 111 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
 112 #else
 113 # define DATE_FMT_LANGINFO() ""
 114 #endif
 115
 116 void
 117 usage (int status)
 118 {
 119   if (status != EXIT_SUCCESS)
 120     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 121              program_name);
 122   else
 123     {
 124       printf (_("\
 125 Usage: %s [OPTION]... [+FORMAT]\n\
 126   or:  %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
 127 "),
 128               program_name, program_name);
 129       fputs (_("\
 130 Display the current time in the given FORMAT, or set the system date.\n\
 131 \n\
 132   -d, --date=STRING         display time described by STRING, not `now'\n\
 133   -f, --file=DATEFILE       like --date once for each line of DATEFILE\n\
 134   -I[TIMESPEC], --iso-8601[=TIMESPEC]  output date/time in ISO 8601 format.\n\
 135                             TIMESPEC=`date' for date only (the default),\n\
 136                             `hours', `minutes', `seconds', or `ns' for date\n\
 137                             and time to the indicated precision.\n\
 138 "), stdout);
 139       fputs (_("\
 140   -r, --reference=FILE      display the last modification time of FILE\n\
 141   -R, --rfc-2822            output date and time in RFC 2822 format.\n\
 142                             Example: Mon, 07 Aug 2006 12:34:56 -0600\n\
 143 "), stdout);
 144       fputs (_("\
 145       --rfc-3339=TIMESPEC   output date and time in RFC 3339 format.\n\
 146                             TIMESPEC=`date', `seconds', or `ns' for\n\
 147                             date and time to the indicated precision.\n\
 148                             Date and time components are separated by\n\
 149                             a single space: 2006-08-07 12:34:56-06:00\n\
 150   -s, --set=STRING          set time described by STRING\n\
 151   -u, --utc, --universal    print or set Coordinated Universal Time\n\
 152 "), stdout);
 153       fputs (HELP_OPTION_DESCRIPTION, stdout);
 154       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 155       fputs (_("\
 156 \n\
 157 FORMAT controls the output.  Interpreted sequences are:\n\
 158 \n\
 159   %%   a literal %\n\
 160   %a   locale's abbreviated weekday name (e.g., Sun)\n\
 161 "), stdout);
 162       fputs (_("\
 163   %A   locale's full weekday name (e.g., Sunday)\n\
 164   %b   locale's abbreviated month name (e.g., Jan)\n\
 165   %B   locale's full month name (e.g., January)\n\
 166   %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)\n\
 167 "), stdout);
 168       fputs (_("\
 169   %C   century; like %Y, except omit last two digits (e.g., 20)\n\
 170   %d   day of month (e.g., 01)\n\
 171   %D   date; same as %m/%d/%y\n\
 172   %e   day of month, space padded; same as %_d\n\
 173 "), stdout);
 174       fputs (_("\
 175   %F   full date; same as %Y-%m-%d\n\
 176   %g   last two digits of year of ISO week number (see %G)\n\
 177   %G   year of ISO week number (see %V); normally useful only with %V\n\
 178 "), stdout);
 179       fputs (_("\
 180   %h   same as %b\n\
 181   %H   hour (00..23)\n\
 182   %I   hour (01..12)\n\
 183   %j   day of year (001..366)\n\
 184 "), stdout);
 185       fputs (_("\
 186   %k   hour, space padded ( 0..23); same as %_H\n\
 187   %l   hour, space padded ( 1..12); same as %_I\n\
 188   %m   month (01..12)\n\
 189   %M   minute (00..59)\n\
 190 "), stdout);
 191       fputs (_("\
 192   %n   a newline\n\
 193   %N   nanoseconds (000000000..999999999)\n\
 194   %p   locale's equivalent of either AM or PM; blank if not known\n\
 195   %P   like %p, but lower case\n\
 196   %r   locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
 197   %R   24-hour hour and minute; same as %H:%M\n\
 198   %s   seconds since 1970-01-01 00:00:00 UTC\n\
 199 "), stdout);
 200       fputs (_("\
 201   %S   second (00..60)\n\
 202   %t   a tab\n\
 203   %T   time; same as %H:%M:%S\n\
 204   %u   day of week (1..7); 1 is Monday\n\
 205 "), stdout);
 206       fputs (_("\
 207   %U   week number of year, with Sunday as first day of week (00..53)\n\
 208   %V   ISO week number, with Monday as first day of week (01..53)\n\
 209   %w   day of week (0..6); 0 is Sunday\n\
 210   %W   week number of year, with Monday as first day of week (00..53)\n\
 211 "), stdout);
 212       fputs (_("\
 213   %x   locale's date representation (e.g., 12/31/99)\n\
 214   %X   locale's time representation (e.g., 23:13:48)\n\
 215   %y   last two digits of year (00..99)\n\
 216   %Y   year\n\
 217 "), stdout);
 218       fputs (_("\
 219   %z   +hhmm numeric time zone (e.g., -0400)\n\
 220   %:z  +hh:mm numeric time zone (e.g., -04:00)\n\
 221   %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
 222   %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
 223   %Z   alphabetic time zone abbreviation (e.g., EDT)\n\
 224 \n\
 225 By default, date pads numeric fields with zeroes.\n\
 226 "), stdout);
 227       fputs (_("\
 228 The following optional flags may follow `%':\n\
 229 \n\
 230   -  (hyphen) do not pad the field\n\
 231   _  (underscore) pad with spaces\n\
 232   0  (zero) pad with zeros\n\
 233   ^  use upper case if possible\n\
 234   #  use opposite case if possible\n\
 235 "), stdout);
 236       fputs (_("\
 237 \n\
 238 After any flags comes an optional field width, as a decimal number;\n\
 239 then an optional modifier, which is either\n\
 240 E to use the locale's alternate representations if available, or\n\
 241 O to use the locale's alternate numeric symbols if available.\n\
 242 "), stdout);
 243       fputs (_("\
 244 \n\
 245 Examples:\n\
 246 Convert seconds since the epoch (1970-01-01 UTC) to a date\n\
 247   $ date --date='@2147483647'\n\
 248 \n\
 249 Show the time on the west coast of the US (use tzselect(1) to find TZ)\n\
 250   $ TZ='America/Los_Angeles' date\n\
 251 \n\
 252 Show the local time for 9AM next Friday on the west coast of the US\n\
 253   $ date --date='TZ=\"America/Los_Angeles\" 09:00 next Fri'\n\
 254 "), stdout);
 255       emit_ancillary_info ();
 256     }
 257   exit (status);
 258 }
 259
 260 /* Parse each line in INPUT_FILENAME as with --date and display each
 261    resulting time and date.  If the file cannot be opened, tell why
 262    then exit.  Issue a diagnostic for any lines that cannot be parsed.
 263    Return true if successful.  */
 264
 265 static bool
 266 batch_convert (const char *input_filename, const char *format)
 267 {
 268   bool ok;
 269   FILE *in_stream;
 270   char *line;
 271   size_t buflen;
 272   struct timespec when;
 273
 274   if (STREQ (input_filename, "-"))
 275     {
 276       input_filename = _("standard input");
 277       in_stream = stdin;
 278     }
 279   else
 280     {
 281       in_stream = fopen (input_filename, "r");
 282       if (in_stream == NULL)
 283         {
 284           error (EXIT_FAILURE, errno, "%s", quote (input_filename));
 285         }
 286     }
 287
 288   line = NULL;
 289   buflen = 0;
 290   ok = true;
 291   while (1)
 292     {
 293       ssize_t line_length = getline (&line, &buflen, in_stream);
 294       if (line_length < 0)
 295         {
 296           /* FIXME: detect/handle error here.  */
 297           break;
 298         }
 299
 300       if (! parse_datetime (&when, line, NULL))
 301         {
 302           if (line[line_length - 1] == '\n')
 303             line[line_length - 1] = '\0';
 304           error (0, 0, _("invalid date %s"), quote (line));
 305           ok = false;
 306         }
 307       else
 308         {
 309           ok &= show_date (format, when);
 310         }
 311     }
 312
 313   if (fclose (in_stream) == EOF)
 314     error (EXIT_FAILURE, errno, "%s", quote (input_filename));
 315
 316   free (line);
 317
 318   return ok;
 319 }
 320
 321 int
 322 main (int argc, char **argv)
 323 {
 324   int optc;
 325   const char *datestr = NULL;
 326   const char *set_datestr = NULL;
 327   struct timespec when;
 328   bool set_date = false;
 329   char const *format = NULL;
 330   char *batch_file = NULL;
 331   char *reference = NULL;
 332   struct stat refstats;
 333   bool ok;
 334   int option_specified_date;
 335
 336   initialize_main (&argc, &argv);
 337   set_program_name (argv[0]);
 338   setlocale (LC_ALL, "");
 339   bindtextdomain (PACKAGE, LOCALEDIR);
 340   textdomain (PACKAGE);
 341
 342   atexit (close_stdout);
 343
 344   while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
 345          != -1)
 346     {
 347       char const *new_format = NULL;
 348
 349       switch (optc)
 350         {
 351         case 'd':
 352           datestr = optarg;
 353           break;
 354         case 'f':
 355           batch_file = optarg;
 356           break;
 357         case RFC_3339_OPTION:
 358           {
 359             static char const rfc_3339_format[][32] =
 360               {
 361                 "%Y-%m-%d",
 362                 "%Y-%m-%d %H:%M:%S%:z",
 363                 "%Y-%m-%d %H:%M:%S.%N%:z"
 364               };
 365             enum Time_spec i =
 366               XARGMATCH ("--rfc-3339", optarg,
 367                          time_spec_string + 2, time_spec + 2);
 368             new_format = rfc_3339_format[i];
 369             break;
 370           }
 371         case 'I':
 372           {
 373             static char const iso_8601_format[][32] =
 374               {
 375                 "%Y-%m-%d",
 376                 "%Y-%m-%dT%H:%M:%S%z",
 377                 "%Y-%m-%dT%H:%M:%S,%N%z",
 378                 "%Y-%m-%dT%H%z",
 379                 "%Y-%m-%dT%H:%M%z"
 380               };
 381             enum Time_spec i =
 382               (optarg
 383                ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
 384                : TIME_SPEC_DATE);
 385             new_format = iso_8601_format[i];
 386             break;
 387           }
 388         case 'r':
 389           reference = optarg;
 390           break;
 391         case 'R':
 392           new_format = rfc_2822_format;
 393           break;
 394         case 's':
 395           set_datestr = optarg;
 396           set_date = true;
 397           break;
 398         case 'u':
 399           /* POSIX says that `date -u' is equivalent to setting the TZ
 400              environment variable, so this option should do nothing other
 401              than setting TZ.  */
 402           if (putenv (bad_cast ("TZ=UTC0")) != 0)
 403             xalloc_die ();
 404           TZSET;
 405           break;
 406         case_GETOPT_HELP_CHAR;
 407         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 408         default:
 409           usage (EXIT_FAILURE);
 410         }
 411
 412       if (new_format)
 413         {
 414           if (format)
 415             error (EXIT_FAILURE, 0, _("multiple output formats specified"));
 416           format = new_format;
 417         }
 418     }
 419
 420   option_specified_date = ((datestr ? 1 : 0)
 421                            + (batch_file ? 1 : 0)
 422                            + (reference ? 1 : 0));
 423
 424   if (option_specified_date > 1)
 425     {
 426       error (0, 0,
 427         _("the options to specify dates for printing are mutually exclusive"));
 428       usage (EXIT_FAILURE);
 429     }
 430
 431   if (set_date && option_specified_date)
 432     {
 433       error (0, 0,
 434           _("the options to print and set the time may not be used together"));
 435       usage (EXIT_FAILURE);
 436     }
 437
 438   if (optind < argc)
 439     {
 440       if (optind + 1 < argc)
 441         {
 442           error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 443           usage (EXIT_FAILURE);
 444         }
 445
 446       if (argv[optind][0] == '+')
 447         {
 448           if (format)
 449             error (EXIT_FAILURE, 0, _("multiple output formats specified"));
 450           format = argv[optind++] + 1;
 451         }
 452       else if (set_date || option_specified_date)
 453         {
 454           error (0, 0,
 455                  _("the argument %s lacks a leading `+';\n"
 456                    "when using an option to specify date(s), any non-option\n"
 457                    "argument must be a format string beginning with `+'"),
 458                  quote (argv[optind]));
 459           usage (EXIT_FAILURE);
 460         }
 461     }
 462
 463   if (!format)
 464     {
 465       format = DATE_FMT_LANGINFO ();
 466       if (! *format)
 467         {
 468           /* Do not wrap the following literal format string with _(...).
 469              For example, suppose LC_ALL is unset, LC_TIME=POSIX,
 470              and LANG="ko_KR".  In that case, POSIX says that LC_TIME
 471              determines the format and contents of date and time strings
 472              written by date, which means "date" must generate output
 473              using the POSIX locale; but adding _() would cause "date"
 474              to use a Korean translation of the format.  */
 475           format = "%a %b %e %H:%M:%S %Z %Y";
 476         }
 477     }
 478
 479   if (batch_file != NULL)
 480     ok = batch_convert (batch_file, format);
 481   else
 482     {
 483       bool valid_date = true;
 484       ok = true;
 485
 486       if (!option_specified_date && !set_date)
 487         {
 488           if (optind < argc)
 489             {
 490               /* Prepare to set system clock to the specified date/time
 491                  given in the POSIX-format.  */
 492               set_date = true;
 493               datestr = argv[optind];
 494               valid_date = posixtime (&when.tv_sec,
 495                                       datestr,
 496                                       (PDS_TRAILING_YEAR
 497                                        | PDS_CENTURY | PDS_SECONDS));
 498               when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
 499             }
 500           else
 501             {
 502               /* Prepare to print the current date/time.  */
 503               gettime (&when);
 504             }
 505         }
 506       else
 507         {
 508           /* (option_specified_date || set_date) */
 509           if (reference != NULL)
 510             {
 511               if (stat (reference, &refstats) != 0)
 512                 error (EXIT_FAILURE, errno, "%s", reference);
 513               when = get_stat_mtime (&refstats);
 514             }
 515           else
 516             {
 517               if (set_datestr)
 518                 datestr = set_datestr;
 519               valid_date = parse_datetime (&when, datestr, NULL);
 520             }
 521         }
 522
 523       if (! valid_date)
 524         error (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
 525
 526       if (set_date)
 527         {
 528           /* Set the system clock to the specified date, then regardless of
 529              the success of that operation, format and print that date.  */
 530           if (settime (&when) != 0)
 531             {
 532               error (0, errno, _("cannot set date"));
 533               ok = false;
 534             }
 535         }
 536
 537       ok &= show_date (format, when);
 538     }
 539
 540   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 541 }
 542
 543 /* Display the date and/or time in WHEN according to the format specified
 544    in FORMAT, followed by a newline.  Return true if successful.  */
 545
 546 static bool
 547 show_date (const char *format, struct timespec when)
 548 {
 549   struct tm *tm;
 550
 551   tm = localtime (&when.tv_sec);
 552   if (! tm)
 553     {
 554       char buf[INT_BUFSIZE_BOUND (intmax_t)];
 555       error (0, 0, _("time %s is out of range"), timetostr (when.tv_sec, buf));
 556       return false;
 557     }
 558
 559   if (format == rfc_2822_format)
 560     setlocale (LC_TIME, "C");
 561   fprintftime (stdout, format, tm, 0, when.tv_nsec);
 562   fputc ('\n', stdout);
 563   if (format == rfc_2822_format)
 564     setlocale (LC_TIME, "");
 565
 566   return true;
 567 }