src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 1989-2009 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 "getdate.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'}, /* Deprecated.  */
  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 "), stdout);
 135       fputs (_("\
 136   -r, --reference=FILE      display the last modification time of FILE\n\
 137   -R, --rfc-2822            output date and time in RFC 2822 format.\n\
 138                             Example: Mon, 07 Aug 2006 12:34:56 -0600\n\
 139 "), stdout);
 140       fputs (_("\
 141       --rfc-3339=TIMESPEC   output date and time in RFC 3339 format.\n\
 142                             TIMESPEC=`date', `seconds', or `ns' for\n\
 143                             date and time to the indicated precision.\n\
 144                             Date and time components are separated by\n\
 145                             a single space: 2006-08-07 12:34:56-06:00\n\
 146   -s, --set=STRING          set time described by STRING\n\
 147   -u, --utc, --universal    print or set Coordinated Universal Time\n\
 148 "), stdout);
 149       fputs (HELP_OPTION_DESCRIPTION, stdout);
 150       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 151       fputs (_("\
 152 \n\
 153 FORMAT controls the output.  Interpreted sequences are:\n\
 154 \n\
 155   %%   a literal %\n\
 156   %a   locale's abbreviated weekday name (e.g., Sun)\n\
 157 "), stdout);
 158       fputs (_("\
 159   %A   locale's full weekday name (e.g., Sunday)\n\
 160   %b   locale's abbreviated month name (e.g., Jan)\n\
 161   %B   locale's full month name (e.g., January)\n\
 162   %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)\n\
 163 "), stdout);
 164       fputs (_("\
 165   %C   century; like %Y, except omit last two digits (e.g., 20)\n\
 166   %d   day of month (e.g, 01)\n\
 167   %D   date; same as %m/%d/%y\n\
 168   %e   day of month, space padded; same as %_d\n\
 169 "), stdout);
 170       fputs (_("\
 171   %F   full date; same as %Y-%m-%d\n\
 172   %g   last two digits of year of ISO week number (see %G)\n\
 173   %G   year of ISO week number (see %V); normally useful only with %V\n\
 174 "), stdout);
 175       fputs (_("\
 176   %h   same as %b\n\
 177   %H   hour (00..23)\n\
 178   %I   hour (01..12)\n\
 179   %j   day of year (001..366)\n\
 180 "), stdout);
 181       fputs (_("\
 182   %k   hour ( 0..23)\n\
 183   %l   hour ( 1..12)\n\
 184   %m   month (01..12)\n\
 185   %M   minute (00..59)\n\
 186 "), stdout);
 187       fputs (_("\
 188   %n   a newline\n\
 189   %N   nanoseconds (000000000..999999999)\n\
 190   %p   locale's equivalent of either AM or PM; blank if not known\n\
 191   %P   like %p, but lower case\n\
 192   %r   locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
 193   %R   24-hour hour and minute; same as %H:%M\n\
 194   %s   seconds since 1970-01-01 00:00:00 UTC\n\
 195 "), stdout);
 196       fputs (_("\
 197   %S   second (00..60)\n\
 198   %t   a tab\n\
 199   %T   time; same as %H:%M:%S\n\
 200   %u   day of week (1..7); 1 is Monday\n\
 201 "), stdout);
 202       fputs (_("\
 203   %U   week number of year, with Sunday as first day of week (00..53)\n\
 204   %V   ISO week number, with Monday as first day of week (01..53)\n\
 205   %w   day of week (0..6); 0 is Sunday\n\
 206   %W   week number of year, with Monday as first day of week (00..53)\n\
 207 "), stdout);
 208       fputs (_("\
 209   %x   locale's date representation (e.g., 12/31/99)\n\
 210   %X   locale's time representation (e.g., 23:13:48)\n\
 211   %y   last two digits of year (00..99)\n\
 212   %Y   year\n\
 213 "), stdout);
 214       fputs (_("\
 215   %z   +hhmm numeric timezone (e.g., -0400)\n\
 216   %:z  +hh:mm numeric timezone (e.g., -04:00)\n\
 217   %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
 218   %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
 219   %Z   alphabetic time zone abbreviation (e.g., EDT)\n\
 220 \n\
 221 By default, date pads numeric fields with zeroes.\n\
 222 "), stdout);
 223       fputs (_("\
 224 The following optional flags may follow `%':\n\
 225 \n\
 226   -  (hyphen) do not pad the field\n\
 227   _  (underscore) pad with spaces\n\
 228   0  (zero) pad with zeros\n\
 229   ^  use upper case if possible\n\
 230   #  use opposite case if possible\n\
 231 "), stdout);
 232       fputs (_("\
 233 \n\
 234 After any flags comes an optional field width, as a decimal number;\n\
 235 then an optional modifier, which is either\n\
 236 E to use the locale's alternate representations if available, or\n\
 237 O to use the locale's alternate numeric symbols if available.\n\
 238 "), stdout);
 239       emit_ancillary_info ();
 240     }
 241   exit (status);
 242 }
 243
 244 /* Parse each line in INPUT_FILENAME as with --date and display each
 245    resulting time and date.  If the file cannot be opened, tell why
 246    then exit.  Issue a diagnostic for any lines that cannot be parsed.
 247    Return true if successful.  */
 248
 249 static bool
 250 batch_convert (const char *input_filename, const char *format)
 251 {
 252   bool ok;
 253   FILE *in_stream;
 254   char *line;
 255   size_t buflen;
 256   struct timespec when;
 257
 258   if (STREQ (input_filename, "-"))
 259     {
 260       input_filename = _("standard input");
 261       in_stream = stdin;
 262     }
 263   else
 264     {
 265       in_stream = fopen (input_filename, "r");
 266       if (in_stream == NULL)
 267         {
 268           error (EXIT_FAILURE, errno, "%s", quote (input_filename));
 269         }
 270     }
 271
 272   line = NULL;
 273   buflen = 0;
 274   ok = true;
 275   while (1)
 276     {
 277       ssize_t line_length = getline (&line, &buflen, in_stream);
 278       if (line_length < 0)
 279         {
 280           /* FIXME: detect/handle error here.  */
 281           break;
 282         }
 283
 284       if (! get_date (&when, line, NULL))
 285         {
 286           if (line[line_length - 1] == '\n')
 287             line[line_length - 1] = '\0';
 288           error (0, 0, _("invalid date %s"), quote (line));
 289           ok = false;
 290         }
 291       else
 292         {
 293           ok &= show_date (format, when);
 294         }
 295     }
 296
 297   if (fclose (in_stream) == EOF)
 298     error (EXIT_FAILURE, errno, "%s", quote (input_filename));
 299
 300   free (line);
 301
 302   return ok;
 303 }
 304
 305 int
 306 main (int argc, char **argv)
 307 {
 308   int optc;
 309   const char *datestr = NULL;
 310   const char *set_datestr = NULL;
 311   struct timespec when;
 312   bool set_date = false;
 313   char const *format = NULL;
 314   char *batch_file = NULL;
 315   char *reference = NULL;
 316   struct stat refstats;
 317   bool ok;
 318   int option_specified_date;
 319
 320   initialize_main (&argc, &argv);
 321   set_program_name (argv[0]);
 322   setlocale (LC_ALL, "");
 323   bindtextdomain (PACKAGE, LOCALEDIR);
 324   textdomain (PACKAGE);
 325
 326   atexit (close_stdout);
 327
 328   while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
 329          != -1)
 330     {
 331       char const *new_format = NULL;
 332
 333       switch (optc)
 334         {
 335         case 'd':
 336           datestr = optarg;
 337           break;
 338         case 'f':
 339           batch_file = optarg;
 340           break;
 341         case RFC_3339_OPTION:
 342           {
 343             static char const rfc_3339_format[][32] =
 344               {
 345                 "%Y-%m-%d",
 346                 "%Y-%m-%d %H:%M:%S%:z",
 347                 "%Y-%m-%d %H:%M:%S.%N%:z"
 348               };
 349             enum Time_spec i =
 350               XARGMATCH ("--rfc-3339", optarg,
 351                          time_spec_string + 2, time_spec + 2);
 352             new_format = rfc_3339_format[i];
 353             break;
 354           }
 355         case 'I':
 356           {
 357             static char const iso_8601_format[][32] =
 358               {
 359                 "%Y-%m-%d",
 360                 "%Y-%m-%dT%H:%M:%S%z",
 361                 "%Y-%m-%dT%H:%M:%S,%N%z",
 362                 "%Y-%m-%dT%H%z",
 363                 "%Y-%m-%dT%H:%M%z"
 364               };
 365             enum Time_spec i =
 366               (optarg
 367                ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
 368                : TIME_SPEC_DATE);
 369             new_format = iso_8601_format[i];
 370             break;
 371           }
 372         case 'r':
 373           reference = optarg;
 374           break;
 375         case 'R':
 376           new_format = rfc_2822_format;
 377           break;
 378         case 's':
 379           set_datestr = optarg;
 380           set_date = true;
 381           break;
 382         case 'u':
 383           /* POSIX says that `date -u' is equivalent to setting the TZ
 384              environment variable, so this option should do nothing other
 385              than setting TZ.  */
 386           if (putenv (bad_cast ("TZ=UTC0")) != 0)
 387             xalloc_die ();
 388           TZSET;
 389           break;
 390         case_GETOPT_HELP_CHAR;
 391         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 392         default:
 393           usage (EXIT_FAILURE);
 394         }
 395
 396       if (new_format)
 397         {
 398           if (format)
 399             error (EXIT_FAILURE, 0, _("multiple output formats specified"));
 400           format = new_format;
 401         }
 402     }
 403
 404   option_specified_date = ((datestr ? 1 : 0)
 405                            + (batch_file ? 1 : 0)
 406                            + (reference ? 1 : 0));
 407
 408   if (option_specified_date > 1)
 409     {
 410       error (0, 0,
 411         _("the options to specify dates for printing are mutually exclusive"));
 412       usage (EXIT_FAILURE);
 413     }
 414
 415   if (set_date && option_specified_date)
 416     {
 417       error (0, 0,
 418           _("the options to print and set the time may not be used together"));
 419       usage (EXIT_FAILURE);
 420     }
 421
 422   if (optind < argc)
 423     {
 424       if (optind + 1 < argc)
 425         {
 426           error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 427           usage (EXIT_FAILURE);
 428         }
 429
 430       if (argv[optind][0] == '+')
 431         {
 432           if (format)
 433             error (EXIT_FAILURE, 0, _("multiple output formats specified"));
 434           format = argv[optind++] + 1;
 435         }
 436       else if (set_date || option_specified_date)
 437         {
 438           error (0, 0,
 439                  _("the argument %s lacks a leading `+';\n"
 440                    "when using an option to specify date(s), any non-option\n"
 441                    "argument must be a format string beginning with `+'"),
 442                  quote (argv[optind]));
 443           usage (EXIT_FAILURE);
 444         }
 445     }
 446
 447   if (!format)
 448     {
 449       format = DATE_FMT_LANGINFO ();
 450       if (! *format)
 451         {
 452           /* Do not wrap the following literal format string with _(...).
 453              For example, suppose LC_ALL is unset, LC_TIME="POSIX",
 454              and LANG="ko_KR".  In that case, POSIX says that LC_TIME
 455              determines the format and contents of date and time strings
 456              written by date, which means "date" must generate output
 457              using the POSIX locale; but adding _() would cause "date"
 458              to use a Korean translation of the format.  */
 459           format = "%a %b %e %H:%M:%S %Z %Y";
 460         }
 461     }
 462
 463   if (batch_file != NULL)
 464     ok = batch_convert (batch_file, format);
 465   else
 466     {
 467       bool valid_date = true;
 468       ok = true;
 469
 470       if (!option_specified_date && !set_date)
 471         {
 472           if (optind < argc)
 473             {
 474               /* Prepare to set system clock to the specified date/time
 475                  given in the POSIX-format.  */
 476               set_date = true;
 477               datestr = argv[optind];
 478               valid_date = posixtime (&when.tv_sec,
 479                                       datestr,
 480                                       (PDS_TRAILING_YEAR
 481                                        | PDS_CENTURY | PDS_SECONDS));
 482               when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
 483             }
 484           else
 485             {
 486               /* Prepare to print the current date/time.  */
 487               gettime (&when);
 488             }
 489         }
 490       else
 491         {
 492           /* (option_specified_date || set_date) */
 493           if (reference != NULL)
 494             {
 495               if (stat (reference, &refstats) != 0)
 496                 error (EXIT_FAILURE, errno, "%s", reference);
 497               when = get_stat_mtime (&refstats);
 498             }
 499           else
 500             {
 501               if (set_datestr)
 502                 datestr = set_datestr;
 503               valid_date = get_date (&when, datestr, NULL);
 504             }
 505         }
 506
 507       if (! valid_date)
 508         error (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
 509
 510       if (set_date)
 511         {
 512           /* Set the system clock to the specified date, then regardless of
 513              the success of that operation, format and print that date.  */
 514           if (settime (&when) != 0)
 515             {
 516               error (0, errno, _("cannot set date"));
 517               ok = false;
 518             }
 519         }
 520
 521       ok &= show_date (format, when);
 522     }
 523
 524   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 525 }
 526
 527 /* Display the date and/or time in WHEN according to the format specified
 528    in FORMAT, followed by a newline.  Return true if successful.  */
 529
 530 static bool
 531 show_date (const char *format, struct timespec when)
 532 {
 533   struct tm *tm;
 534
 535   tm = localtime (&when.tv_sec);
 536   if (! tm)
 537     {
 538       char buf[INT_BUFSIZE_BOUND (intmax_t)];
 539       error (0, 0, _("time %s is out of range"), timetostr (when.tv_sec, buf));
 540       return false;
 541     }
 542
 543   if (format == rfc_2822_format)
 544     setlocale (LC_TIME, "C");
 545   fprintftime (stdout, format, tm, 0, when.tv_nsec);
 546   fputc ('\n', stdout);
 547   if (format == rfc_2822_format)
 548     setlocale (LC_TIME, "");
 549
 550   return true;
 551 }