src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 1989-2016 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 "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 (const char *, 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 RFC 2822.  */
  76 static char const rfc_2822_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   RFC_3339_OPTION = CHAR_MAX + 1,
  83   DEBUG_DATE_PARSING
  84 };
  85
  86 static char const short_options[] = "d:f:I::r:Rs:u";
  87
  88 static struct option const long_options[] =
  89 {
  90   {"date", required_argument, NULL, 'd'},
  91   {"debug", no_argument, NULL, DEBUG_DATE_PARSING},
  92   {"file", required_argument, NULL, 'f'},
  93   {"iso-8601", optional_argument, NULL, 'I'},
  94   {"reference", required_argument, NULL, 'r'},
  95   {"rfc-822", no_argument, NULL, 'R'},
  96   {"rfc-2822", no_argument, NULL, 'R'},
  97   {"rfc-3339", required_argument, NULL, RFC_3339_OPTION},
  98   {"set", required_argument, NULL, 's'},
  99   {"uct", no_argument, NULL, 'u'},
 100   {"utc", no_argument, NULL, 'u'},
 101   {"universal", no_argument, NULL, 'u'},
 102   {GETOPT_HELP_OPTION_DECL},
 103   {GETOPT_VERSION_OPTION_DECL},
 104   {NULL, 0, NULL, 0}
 105 };
 106
 107 /* flags for parse_datetime2 */
 108 static unsigned int parse_datetime_flags;
 109
 110 #if LOCALTIME_CACHE
 111 # define TZSET tzset ()
 112 #else
 113 # define TZSET /* empty */
 114 #endif
 115
 116 #ifdef _DATE_FMT
 117 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
 118 #else
 119 # define DATE_FMT_LANGINFO() ""
 120 #endif
 121
 122 void
 123 usage (int status)
 124 {
 125   if (status != EXIT_SUCCESS)
 126     emit_try_help ();
 127   else
 128     {
 129       printf (_("\
 130 Usage: %s [OPTION]... [+FORMAT]\n\
 131   or:  %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
 132 "),
 133               program_name, program_name);
 134       fputs (_("\
 135 Display the current time in the given FORMAT, or set the system date.\n\
 136 "), stdout);
 137
 138       emit_mandatory_arg_note ();
 139
 140       fputs (_("\
 141   -d, --date=STRING          display time described by STRING, not 'now'\n\
 142 "), stdout);
 143       fputs (_("\
 144       --debug                annotate the parsed date,\n\
 145                               and warn about questionable usage to stderr\n\
 146 "), stdout);
 147       fputs (_("\
 148   -f, --file=DATEFILE        like --date; once for each line of DATEFILE\n\
 149 "), stdout);
 150       fputs (_("\
 151   -I[FMT], --iso-8601[=FMT]  output date/time in ISO 8601 format.\n\
 152                                FMT='date' for date only (the default),\n\
 153                                'hours', 'minutes', 'seconds', or 'ns'\n\
 154                                for date and time to the indicated precision.\n\
 155                                Example: 2006-08-14T02:34:56-06:00\n\
 156 "), stdout);
 157       fputs (_("\
 158   -R, --rfc-2822             output date and time in RFC 2822 format.\n\
 159                                Example: Mon, 14 Aug 2006 02:34:56 -0600\n\
 160 "), stdout);
 161       fputs (_("\
 162       --rfc-3339=FMT         output date/time in RFC 3339 format.\n\
 163                                FMT='date', 'seconds', or 'ns'\n\
 164                                for date and time to the indicated precision.\n\
 165                                Example: 2006-08-14 02:34:56-06:00\n\
 166 "), stdout);
 167       fputs (_("\
 168   -r, --reference=FILE       display the last modification time of FILE\n\
 169 "), stdout);
 170       fputs (_("\
 171   -s, --set=STRING           set time described by STRING\n\
 172   -u, --utc, --universal     print or set Coordinated Universal Time (UTC)\n\
 173 "), stdout);
 174       fputs (HELP_OPTION_DESCRIPTION, stdout);
 175       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 176       fputs (_("\
 177 \n\
 178 FORMAT controls the output.  Interpreted sequences are:\n\
 179 \n\
 180   %%   a literal %\n\
 181   %a   locale's abbreviated weekday name (e.g., Sun)\n\
 182 "), stdout);
 183       fputs (_("\
 184   %A   locale's full weekday name (e.g., Sunday)\n\
 185   %b   locale's abbreviated month name (e.g., Jan)\n\
 186   %B   locale's full month name (e.g., January)\n\
 187   %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)\n\
 188 "), stdout);
 189       fputs (_("\
 190   %C   century; like %Y, except omit last two digits (e.g., 20)\n\
 191   %d   day of month (e.g., 01)\n\
 192   %D   date; same as %m/%d/%y\n\
 193   %e   day of month, space padded; same as %_d\n\
 194 "), stdout);
 195       fputs (_("\
 196   %F   full date; same as %Y-%m-%d\n\
 197   %g   last two digits of year of ISO week number (see %G)\n\
 198   %G   year of ISO week number (see %V); normally useful only with %V\n\
 199 "), stdout);
 200       fputs (_("\
 201   %h   same as %b\n\
 202   %H   hour (00..23)\n\
 203   %I   hour (01..12)\n\
 204   %j   day of year (001..366)\n\
 205 "), stdout);
 206       fputs (_("\
 207   %k   hour, space padded ( 0..23); same as %_H\n\
 208   %l   hour, space padded ( 1..12); same as %_I\n\
 209   %m   month (01..12)\n\
 210   %M   minute (00..59)\n\
 211 "), stdout);
 212       fputs (_("\
 213   %n   a newline\n\
 214   %N   nanoseconds (000000000..999999999)\n\
 215   %p   locale's equivalent of either AM or PM; blank if not known\n\
 216   %P   like %p, but lower case\n\
 217   %q   quarter of year (1..4)\n\
 218   %r   locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
 219   %R   24-hour hour and minute; same as %H:%M\n\
 220   %s   seconds since 1970-01-01 00:00:00 UTC\n\
 221 "), stdout);
 222       fputs (_("\
 223   %S   second (00..60)\n\
 224   %t   a tab\n\
 225   %T   time; same as %H:%M:%S\n\
 226   %u   day of week (1..7); 1 is Monday\n\
 227 "), stdout);
 228       fputs (_("\
 229   %U   week number of year, with Sunday as first day of week (00..53)\n\
 230   %V   ISO week number, with Monday as first day of week (01..53)\n\
 231   %w   day of week (0..6); 0 is Sunday\n\
 232   %W   week number of year, with Monday as first day of week (00..53)\n\
 233 "), stdout);
 234       fputs (_("\
 235   %x   locale's date representation (e.g., 12/31/99)\n\
 236   %X   locale's time representation (e.g., 23:13:48)\n\
 237   %y   last two digits of year (00..99)\n\
 238   %Y   year\n\
 239 "), stdout);
 240       fputs (_("\
 241   %z   +hhmm numeric time zone (e.g., -0400)\n\
 242   %:z  +hh:mm numeric time zone (e.g., -04:00)\n\
 243   %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
 244   %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
 245   %Z   alphabetic time zone abbreviation (e.g., EDT)\n\
 246 \n\
 247 By default, date pads numeric fields with zeroes.\n\
 248 "), stdout);
 249       fputs (_("\
 250 The following optional flags may follow '%':\n\
 251 \n\
 252   -  (hyphen) do not pad the field\n\
 253   _  (underscore) pad with spaces\n\
 254   0  (zero) pad with zeros\n\
 255   ^  use upper case if possible\n\
 256   #  use opposite case if possible\n\
 257 "), stdout);
 258       fputs (_("\
 259 \n\
 260 After any flags comes an optional field width, as a decimal number;\n\
 261 then an optional modifier, which is either\n\
 262 E to use the locale's alternate representations if available, or\n\
 263 O to use the locale's alternate numeric symbols if available.\n\
 264 "), stdout);
 265       fputs (_("\
 266 \n\
 267 Examples:\n\
 268 Convert seconds since the epoch (1970-01-01 UTC) to a date\n\
 269   $ date --date='@2147483647'\n\
 270 \n\
 271 Show the time on the west coast of the US (use tzselect(1) to find TZ)\n\
 272   $ TZ='America/Los_Angeles' date\n\
 273 \n\
 274 Show the local time for 9AM next Friday on the west coast of the US\n\
 275   $ date --date='TZ=\"America/Los_Angeles\" 09:00 next Fri'\n\
 276 "), stdout);
 277       emit_ancillary_info (PROGRAM_NAME);
 278     }
 279   exit (status);
 280 }
 281
 282 /* Parse each line in INPUT_FILENAME as with --date and display each
 283    resulting time and date.  If the file cannot be opened, tell why
 284    then exit.  Issue a diagnostic for any lines that cannot be parsed.
 285    Return true if successful.  */
 286
 287 static bool
 288 batch_convert (const char *input_filename, const char *format, timezone_t tz)
 289 {
 290   bool ok;
 291   FILE *in_stream;
 292   char *line;
 293   size_t buflen;
 294   struct timespec when;
 295
 296   if (STREQ (input_filename, "-"))
 297     {
 298       input_filename = _("standard input");
 299       in_stream = stdin;
 300     }
 301   else
 302     {
 303       in_stream = fopen (input_filename, "r");
 304       if (in_stream == NULL)
 305         {
 306           die (EXIT_FAILURE, errno, "%s", quotef (input_filename));
 307         }
 308     }
 309
 310   line = NULL;
 311   buflen = 0;
 312   ok = true;
 313   while (1)
 314     {
 315       ssize_t line_length = getline (&line, &buflen, in_stream);
 316       if (line_length < 0)
 317         {
 318           /* FIXME: detect/handle error here.  */
 319           break;
 320         }
 321
 322       if (! parse_datetime2 (&when, line, NULL, parse_datetime_flags))
 323         {
 324           if (line[line_length - 1] == '\n')
 325             line[line_length - 1] = '\0';
 326           error (0, 0, _("invalid date %s"), quote (line));
 327           ok = false;
 328         }
 329       else
 330         {
 331           ok &= show_date (format, when, tz);
 332         }
 333     }
 334
 335   if (fclose (in_stream) == EOF)
 336     die (EXIT_FAILURE, errno, "%s", quotef (input_filename));
 337
 338   free (line);
 339
 340   return ok;
 341 }
 342
 343 int
 344 main (int argc, char **argv)
 345 {
 346   int optc;
 347   const char *datestr = NULL;
 348   const char *set_datestr = NULL;
 349   struct timespec when;
 350   bool set_date = false;
 351   char const *format = NULL;
 352   char *batch_file = NULL;
 353   char *reference = NULL;
 354   struct stat refstats;
 355   bool ok;
 356   int option_specified_date;
 357
 358   initialize_main (&argc, &argv);
 359   set_program_name (argv[0]);
 360   setlocale (LC_ALL, "");
 361   bindtextdomain (PACKAGE, LOCALEDIR);
 362   textdomain (PACKAGE);
 363
 364   atexit (close_stdout);
 365
 366   while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
 367          != -1)
 368     {
 369       char const *new_format = NULL;
 370
 371       switch (optc)
 372         {
 373         case 'd':
 374           datestr = optarg;
 375           break;
 376         case DEBUG_DATE_PARSING:
 377           parse_datetime_flags |= PARSE_DATETIME_DEBUG;
 378           break;
 379         case 'f':
 380           batch_file = optarg;
 381           break;
 382         case RFC_3339_OPTION:
 383           {
 384             static char const rfc_3339_format[][32] =
 385               {
 386                 "%Y-%m-%d",
 387                 "%Y-%m-%d %H:%M:%S%:z",
 388                 "%Y-%m-%d %H:%M:%S.%N%:z"
 389               };
 390             enum Time_spec i =
 391               XARGMATCH ("--rfc-3339", optarg,
 392                          time_spec_string + 2, time_spec + 2);
 393             new_format = rfc_3339_format[i];
 394             break;
 395           }
 396         case 'I':
 397           {
 398             static char const iso_8601_format[][32] =
 399               {
 400                 "%Y-%m-%d",
 401                 "%Y-%m-%dT%H:%M:%S%:z",
 402                 "%Y-%m-%dT%H:%M:%S,%N%:z",
 403                 "%Y-%m-%dT%H%:z",
 404                 "%Y-%m-%dT%H:%M%:z"
 405               };
 406             enum Time_spec i =
 407               (optarg
 408                ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
 409                : TIME_SPEC_DATE);
 410             new_format = iso_8601_format[i];
 411             break;
 412           }
 413         case 'r':
 414           reference = optarg;
 415           break;
 416         case 'R':
 417           new_format = rfc_2822_format;
 418           break;
 419         case 's':
 420           set_datestr = optarg;
 421           set_date = true;
 422           break;
 423         case 'u':
 424           /* POSIX says that 'date -u' is equivalent to setting the TZ
 425              environment variable, so this option should do nothing other
 426              than setting TZ.  */
 427           if (putenv (bad_cast ("TZ=UTC0")) != 0)
 428             xalloc_die ();
 429           TZSET;
 430           break;
 431         case_GETOPT_HELP_CHAR;
 432         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 433         default:
 434           usage (EXIT_FAILURE);
 435         }
 436
 437       if (new_format)
 438         {
 439           if (format)
 440             die (EXIT_FAILURE, 0, _("multiple output formats specified"));
 441           format = new_format;
 442         }
 443     }
 444
 445   option_specified_date = ((datestr ? 1 : 0)
 446                            + (batch_file ? 1 : 0)
 447                            + (reference ? 1 : 0));
 448
 449   if (option_specified_date > 1)
 450     {
 451       error (0, 0,
 452         _("the options to specify dates for printing are mutually exclusive"));
 453       usage (EXIT_FAILURE);
 454     }
 455
 456   if (set_date && option_specified_date)
 457     {
 458       error (0, 0,
 459           _("the options to print and set the time may not be used together"));
 460       usage (EXIT_FAILURE);
 461     }
 462
 463   if (optind < argc)
 464     {
 465       if (optind + 1 < argc)
 466         {
 467           error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 468           usage (EXIT_FAILURE);
 469         }
 470
 471       if (argv[optind][0] == '+')
 472         {
 473           if (format)
 474             die (EXIT_FAILURE, 0, _("multiple output formats specified"));
 475           format = argv[optind++] + 1;
 476         }
 477       else if (set_date || option_specified_date)
 478         {
 479           error (0, 0,
 480                  _("the argument %s lacks a leading '+';\n"
 481                    "when using an option to specify date(s), any non-option\n"
 482                    "argument must be a format string beginning with '+'"),
 483                  quote (argv[optind]));
 484           usage (EXIT_FAILURE);
 485         }
 486     }
 487
 488   if (!format)
 489     {
 490       format = DATE_FMT_LANGINFO ();
 491       if (! *format)
 492         {
 493           /* Do not wrap the following literal format string with _(...).
 494              For example, suppose LC_ALL is unset, LC_TIME=POSIX,
 495              and LANG="ko_KR".  In that case, POSIX says that LC_TIME
 496              determines the format and contents of date and time strings
 497              written by date, which means "date" must generate output
 498              using the POSIX locale; but adding _() would cause "date"
 499              to use a Korean translation of the format.  */
 500           format = "%a %b %e %H:%M:%S %Z %Y";
 501         }
 502     }
 503
 504   timezone_t tz = tzalloc (getenv ("TZ"));
 505
 506   if (batch_file != NULL)
 507     ok = batch_convert (batch_file, format, tz);
 508   else
 509     {
 510       bool valid_date = true;
 511       ok = true;
 512
 513       if (!option_specified_date && !set_date)
 514         {
 515           if (optind < argc)
 516             {
 517               /* Prepare to set system clock to the specified date/time
 518                  given in the POSIX-format.  */
 519               set_date = true;
 520               datestr = argv[optind];
 521               valid_date = posixtime (&when.tv_sec,
 522                                       datestr,
 523                                       (PDS_TRAILING_YEAR
 524                                        | PDS_CENTURY | PDS_SECONDS));
 525               when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
 526             }
 527           else
 528             {
 529               /* Prepare to print the current date/time.  */
 530               gettime (&when);
 531             }
 532         }
 533       else
 534         {
 535           /* (option_specified_date || set_date) */
 536           if (reference != NULL)
 537             {
 538               if (stat (reference, &refstats) != 0)
 539                 die (EXIT_FAILURE, errno, "%s", quotef (reference));
 540               when = get_stat_mtime (&refstats);
 541             }
 542           else
 543             {
 544               if (set_datestr)
 545                 datestr = set_datestr;
 546               valid_date = parse_datetime2 (&when, datestr, NULL,
 547                                             parse_datetime_flags);
 548             }
 549         }
 550
 551       if (! valid_date)
 552         die (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
 553
 554       if (set_date)
 555         {
 556           /* Set the system clock to the specified date, then regardless of
 557              the success of that operation, format and print that date.  */
 558           if (settime (&when) != 0)
 559             {
 560               error (0, errno, _("cannot set date"));
 561               ok = false;
 562             }
 563         }
 564
 565       ok &= show_date (format, when, tz);
 566     }
 567
 568   IF_LINT (tzfree (tz));
 569
 570   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 571 }
 572
 573 /* Display the date and/or time in WHEN according to the format specified
 574    in FORMAT, followed by a newline.  Return true if successful.  */
 575
 576 static bool
 577 show_date (const char *format, struct timespec when, timezone_t tz)
 578 {
 579   struct tm tm;
 580
 581   if (localtime_rz (tz, &when.tv_sec, &tm))
 582     {
 583       if (format == rfc_2822_format)
 584         setlocale (LC_TIME, "C");
 585       fprintftime (stdout, format, &tm, tz, when.tv_nsec);
 586       if (format == rfc_2822_format)
 587         setlocale (LC_TIME, "");
 588       fputc ('\n', stdout);
 589       return true;
 590     }
 591   else
 592     {
 593       char buf[INT_BUFSIZE_BOUND (intmax_t)];
 594       error (0, 0, _("time %s is out of range"),
 595              quote (timetostr (when.tv_sec, buf)));
 596       return false;
 597     }
 598 }