src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 1989-2015 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 "), stdout);
 131
 132       emit_mandatory_arg_note ();
 133
 134       fputs (_("\
 135   -d, --date=STRING          display time described by STRING, not 'now'\n\
 136   -f, --file=DATEFILE        like --date; once for each line of DATEFILE\n\
 137 "), stdout);
 138       fputs (_("\
 139   -I[FMT], --iso-8601[=FMT]  output date/time in ISO 8601 format.\n\
 140                                FMT='date' for date only (the default),\n\
 141                                'hours', 'minutes', 'seconds', or 'ns'\n\
 142                                for date and time to the indicated precision.\n\
 143                                Example: 2006-08-14T02:34:56-0600\n\
 144 "), stdout);
 145       fputs (_("\
 146   -R, --rfc-2822             output date and time in RFC 2822 format.\n\
 147                                Example: Mon, 14 Aug 2006 02:34:56 -0600\n\
 148 "), stdout);
 149       fputs (_("\
 150       --rfc-3339=FMT         output date/time in RFC 3339 format.\n\
 151                                FMT='date', 'seconds', or 'ns'\n\
 152                                for date and time to the indicated precision.\n\
 153                                Example: 2006-08-14 02:34:56-06:00\n\
 154 "), stdout);
 155       fputs (_("\
 156   -r, --reference=FILE       display the last modification time of FILE\n\
 157 "), stdout);
 158       fputs (_("\
 159   -s, --set=STRING           set time described by STRING\n\
 160   -u, --utc, --universal     print or set Coordinated Universal Time (UTC)\n\
 161 "), stdout);
 162       fputs (HELP_OPTION_DESCRIPTION, stdout);
 163       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 164       fputs (_("\
 165 \n\
 166 FORMAT controls the output.  Interpreted sequences are:\n\
 167 \n\
 168   %%   a literal %\n\
 169   %a   locale's abbreviated weekday name (e.g., Sun)\n\
 170 "), stdout);
 171       fputs (_("\
 172   %A   locale's full weekday name (e.g., Sunday)\n\
 173   %b   locale's abbreviated month name (e.g., Jan)\n\
 174   %B   locale's full month name (e.g., January)\n\
 175   %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)\n\
 176 "), stdout);
 177       fputs (_("\
 178   %C   century; like %Y, except omit last two digits (e.g., 20)\n\
 179   %d   day of month (e.g., 01)\n\
 180   %D   date; same as %m/%d/%y\n\
 181   %e   day of month, space padded; same as %_d\n\
 182 "), stdout);
 183       fputs (_("\
 184   %F   full date; same as %Y-%m-%d\n\
 185   %g   last two digits of year of ISO week number (see %G)\n\
 186   %G   year of ISO week number (see %V); normally useful only with %V\n\
 187 "), stdout);
 188       fputs (_("\
 189   %h   same as %b\n\
 190   %H   hour (00..23)\n\
 191   %I   hour (01..12)\n\
 192   %j   day of year (001..366)\n\
 193 "), stdout);
 194       fputs (_("\
 195   %k   hour, space padded ( 0..23); same as %_H\n\
 196   %l   hour, space padded ( 1..12); same as %_I\n\
 197   %m   month (01..12)\n\
 198   %M   minute (00..59)\n\
 199 "), stdout);
 200       fputs (_("\
 201   %n   a newline\n\
 202   %N   nanoseconds (000000000..999999999)\n\
 203   %p   locale's equivalent of either AM or PM; blank if not known\n\
 204   %P   like %p, but lower case\n\
 205   %r   locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
 206   %R   24-hour hour and minute; same as %H:%M\n\
 207   %s   seconds since 1970-01-01 00:00:00 UTC\n\
 208 "), stdout);
 209       fputs (_("\
 210   %S   second (00..60)\n\
 211   %t   a tab\n\
 212   %T   time; same as %H:%M:%S\n\
 213   %u   day of week (1..7); 1 is Monday\n\
 214 "), stdout);
 215       fputs (_("\
 216   %U   week number of year, with Sunday as first day of week (00..53)\n\
 217   %V   ISO week number, with Monday as first day of week (01..53)\n\
 218   %w   day of week (0..6); 0 is Sunday\n\
 219   %W   week number of year, with Monday as first day of week (00..53)\n\
 220 "), stdout);
 221       fputs (_("\
 222   %x   locale's date representation (e.g., 12/31/99)\n\
 223   %X   locale's time representation (e.g., 23:13:48)\n\
 224   %y   last two digits of year (00..99)\n\
 225   %Y   year\n\
 226 "), stdout);
 227       fputs (_("\
 228   %z   +hhmm numeric time zone (e.g., -0400)\n\
 229   %:z  +hh:mm numeric time zone (e.g., -04:00)\n\
 230   %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
 231   %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
 232   %Z   alphabetic time zone abbreviation (e.g., EDT)\n\
 233 \n\
 234 By default, date pads numeric fields with zeroes.\n\
 235 "), stdout);
 236       fputs (_("\
 237 The following optional flags may follow '%':\n\
 238 \n\
 239   -  (hyphen) do not pad the field\n\
 240   _  (underscore) pad with spaces\n\
 241   0  (zero) pad with zeros\n\
 242   ^  use upper case if possible\n\
 243   #  use opposite case if possible\n\
 244 "), stdout);
 245       fputs (_("\
 246 \n\
 247 After any flags comes an optional field width, as a decimal number;\n\
 248 then an optional modifier, which is either\n\
 249 E to use the locale's alternate representations if available, or\n\
 250 O to use the locale's alternate numeric symbols if available.\n\
 251 "), stdout);
 252       fputs (_("\
 253 \n\
 254 Examples:\n\
 255 Convert seconds since the epoch (1970-01-01 UTC) to a date\n\
 256   $ date --date='@2147483647'\n\
 257 \n\
 258 Show the time on the west coast of the US (use tzselect(1) to find TZ)\n\
 259   $ TZ='America/Los_Angeles' date\n\
 260 \n\
 261 Show the local time for 9AM next Friday on the west coast of the US\n\
 262   $ date --date='TZ=\"America/Los_Angeles\" 09:00 next Fri'\n\
 263 "), stdout);
 264       emit_ancillary_info (PROGRAM_NAME);
 265     }
 266   exit (status);
 267 }
 268
 269 /* Parse each line in INPUT_FILENAME as with --date and display each
 270    resulting time and date.  If the file cannot be opened, tell why
 271    then exit.  Issue a diagnostic for any lines that cannot be parsed.
 272    Return true if successful.  */
 273
 274 static bool
 275 batch_convert (const char *input_filename, const char *format)
 276 {
 277   bool ok;
 278   FILE *in_stream;
 279   char *line;
 280   size_t buflen;
 281   struct timespec when;
 282
 283   if (STREQ (input_filename, "-"))
 284     {
 285       input_filename = _("standard input");
 286       in_stream = stdin;
 287     }
 288   else
 289     {
 290       in_stream = fopen (input_filename, "r");
 291       if (in_stream == NULL)
 292         {
 293           error (EXIT_FAILURE, errno, "%s", quote (input_filename));
 294         }
 295     }
 296
 297   line = NULL;
 298   buflen = 0;
 299   ok = true;
 300   while (1)
 301     {
 302       ssize_t line_length = getline (&line, &buflen, in_stream);
 303       if (line_length < 0)
 304         {
 305           /* FIXME: detect/handle error here.  */
 306           break;
 307         }
 308
 309       if (! parse_datetime (&when, line, NULL))
 310         {
 311           if (line[line_length - 1] == '\n')
 312             line[line_length - 1] = '\0';
 313           error (0, 0, _("invalid date %s"), quote (line));
 314           ok = false;
 315         }
 316       else
 317         {
 318           ok &= show_date (format, when);
 319         }
 320     }
 321
 322   if (fclose (in_stream) == EOF)
 323     error (EXIT_FAILURE, errno, "%s", quote (input_filename));
 324
 325   free (line);
 326
 327   return ok;
 328 }
 329
 330 int
 331 main (int argc, char **argv)
 332 {
 333   int optc;
 334   const char *datestr = NULL;
 335   const char *set_datestr = NULL;
 336   struct timespec when;
 337   bool set_date = false;
 338   char const *format = NULL;
 339   char *batch_file = NULL;
 340   char *reference = NULL;
 341   struct stat refstats;
 342   bool ok;
 343   int option_specified_date;
 344
 345   initialize_main (&argc, &argv);
 346   set_program_name (argv[0]);
 347   setlocale (LC_ALL, "");
 348   bindtextdomain (PACKAGE, LOCALEDIR);
 349   textdomain (PACKAGE);
 350
 351   atexit (close_stdout);
 352
 353   while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
 354          != -1)
 355     {
 356       char const *new_format = NULL;
 357
 358       switch (optc)
 359         {
 360         case 'd':
 361           datestr = optarg;
 362           break;
 363         case 'f':
 364           batch_file = optarg;
 365           break;
 366         case RFC_3339_OPTION:
 367           {
 368             static char const rfc_3339_format[][32] =
 369               {
 370                 "%Y-%m-%d",
 371                 "%Y-%m-%d %H:%M:%S%:z",
 372                 "%Y-%m-%d %H:%M:%S.%N%:z"
 373               };
 374             enum Time_spec i =
 375               XARGMATCH ("--rfc-3339", optarg,
 376                          time_spec_string + 2, time_spec + 2);
 377             new_format = rfc_3339_format[i];
 378             break;
 379           }
 380         case 'I':
 381           {
 382             static char const iso_8601_format[][32] =
 383               {
 384                 "%Y-%m-%d",
 385                 "%Y-%m-%dT%H:%M:%S%z",
 386                 "%Y-%m-%dT%H:%M:%S,%N%z",
 387                 "%Y-%m-%dT%H%z",
 388                 "%Y-%m-%dT%H:%M%z"
 389               };
 390             enum Time_spec i =
 391               (optarg
 392                ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
 393                : TIME_SPEC_DATE);
 394             new_format = iso_8601_format[i];
 395             break;
 396           }
 397         case 'r':
 398           reference = optarg;
 399           break;
 400         case 'R':
 401           new_format = rfc_2822_format;
 402           break;
 403         case 's':
 404           set_datestr = optarg;
 405           set_date = true;
 406           break;
 407         case 'u':
 408           /* POSIX says that 'date -u' is equivalent to setting the TZ
 409              environment variable, so this option should do nothing other
 410              than setting TZ.  */
 411           if (putenv (bad_cast ("TZ=UTC0")) != 0)
 412             xalloc_die ();
 413           TZSET;
 414           break;
 415         case_GETOPT_HELP_CHAR;
 416         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 417         default:
 418           usage (EXIT_FAILURE);
 419         }
 420
 421       if (new_format)
 422         {
 423           if (format)
 424             error (EXIT_FAILURE, 0, _("multiple output formats specified"));
 425           format = new_format;
 426         }
 427     }
 428
 429   option_specified_date = ((datestr ? 1 : 0)
 430                            + (batch_file ? 1 : 0)
 431                            + (reference ? 1 : 0));
 432
 433   if (option_specified_date > 1)
 434     {
 435       error (0, 0,
 436         _("the options to specify dates for printing are mutually exclusive"));
 437       usage (EXIT_FAILURE);
 438     }
 439
 440   if (set_date && option_specified_date)
 441     {
 442       error (0, 0,
 443           _("the options to print and set the time may not be used together"));
 444       usage (EXIT_FAILURE);
 445     }
 446
 447   if (optind < argc)
 448     {
 449       if (optind + 1 < argc)
 450         {
 451           error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 452           usage (EXIT_FAILURE);
 453         }
 454
 455       if (argv[optind][0] == '+')
 456         {
 457           if (format)
 458             error (EXIT_FAILURE, 0, _("multiple output formats specified"));
 459           format = argv[optind++] + 1;
 460         }
 461       else if (set_date || option_specified_date)
 462         {
 463           error (0, 0,
 464                  _("the argument %s lacks a leading '+';\n"
 465                    "when using an option to specify date(s), any non-option\n"
 466                    "argument must be a format string beginning with '+'"),
 467                  quote (argv[optind]));
 468           usage (EXIT_FAILURE);
 469         }
 470     }
 471
 472   if (!format)
 473     {
 474       format = DATE_FMT_LANGINFO ();
 475       if (! *format)
 476         {
 477           /* Do not wrap the following literal format string with _(...).
 478              For example, suppose LC_ALL is unset, LC_TIME=POSIX,
 479              and LANG="ko_KR".  In that case, POSIX says that LC_TIME
 480              determines the format and contents of date and time strings
 481              written by date, which means "date" must generate output
 482              using the POSIX locale; but adding _() would cause "date"
 483              to use a Korean translation of the format.  */
 484           format = "%a %b %e %H:%M:%S %Z %Y";
 485         }
 486     }
 487
 488   if (batch_file != NULL)
 489     ok = batch_convert (batch_file, format);
 490   else
 491     {
 492       bool valid_date = true;
 493       ok = true;
 494
 495       if (!option_specified_date && !set_date)
 496         {
 497           if (optind < argc)
 498             {
 499               /* Prepare to set system clock to the specified date/time
 500                  given in the POSIX-format.  */
 501               set_date = true;
 502               datestr = argv[optind];
 503               valid_date = posixtime (&when.tv_sec,
 504                                       datestr,
 505                                       (PDS_TRAILING_YEAR
 506                                        | PDS_CENTURY | PDS_SECONDS));
 507               when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
 508             }
 509           else
 510             {
 511               /* Prepare to print the current date/time.  */
 512               gettime (&when);
 513             }
 514         }
 515       else
 516         {
 517           /* (option_specified_date || set_date) */
 518           if (reference != NULL)
 519             {
 520               if (stat (reference, &refstats) != 0)
 521                 error (EXIT_FAILURE, errno, "%s", reference);
 522               when = get_stat_mtime (&refstats);
 523             }
 524           else
 525             {
 526               if (set_datestr)
 527                 datestr = set_datestr;
 528               valid_date = parse_datetime (&when, datestr, NULL);
 529             }
 530         }
 531
 532       if (! valid_date)
 533         error (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
 534
 535       if (set_date)
 536         {
 537           /* Set the system clock to the specified date, then regardless of
 538              the success of that operation, format and print that date.  */
 539           if (settime (&when) != 0)
 540             {
 541               error (0, errno, _("cannot set date"));
 542               ok = false;
 543             }
 544         }
 545
 546       ok &= show_date (format, when);
 547     }
 548
 549   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 550 }
 551
 552 /* Display the date and/or time in WHEN according to the format specified
 553    in FORMAT, followed by a newline.  Return true if successful.  */
 554
 555 static bool
 556 show_date (const char *format, struct timespec when)
 557 {
 558   struct tm *tm;
 559
 560   tm = localtime (&when.tv_sec);
 561   if (! tm)
 562     {
 563       char buf[INT_BUFSIZE_BOUND (intmax_t)];
 564       error (0, 0, _("time %s is out of range"), timetostr (when.tv_sec, buf));
 565       return false;
 566     }
 567
 568   if (format == rfc_2822_format)
 569     setlocale (LC_TIME, "C");
 570   fprintftime (stdout, format, tm, 0, when.tv_nsec);
 571   fputc ('\n', stdout);
 572   if (format == rfc_2822_format)
 573     setlocale (LC_TIME, "");
 574
 575   return true;
 576 }