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