src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 1989-2002 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 2, or (at your option)
   7    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, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17
  18    David MacKenzie <djm@gnu.ai.mit.edu> */
  19
  20 #include <config.h>
  21 #include <stdio.h>
  22 #include <getopt.h>
  23 #include <sys/types.h>
  24 #if HAVE_LANGINFO_CODESET
  25 # include <langinfo.h>
  26 #endif
  27
  28 #include "system.h"
  29 #include "argmatch.h"
  30 #include "closeout.h"
  31 #include "error.h"
  32 #include "getdate.h"
  33 #include "getline.h"
  34 #include "posixtm.h"
  35 #include "posixver.h"
  36 #include "strftime.h"
  37 #include "timespec.h"
  38
  39 /* The official name of this program (e.g., no `g' prefix).  */
  40 #define PROGRAM_NAME "date"
  41
  42 #define AUTHORS "David MacKenzie"
  43
  44 int putenv ();
  45
  46 static void show_date (const char *format, struct timespec when);
  47
  48 enum Time_spec
  49 {
  50   /* display only the date: 1999-03-25 */
  51   TIME_SPEC_DATE=1,
  52   /* display date and hour: 1999-03-25T03-0500 */
  53   TIME_SPEC_HOURS,
  54   /* display date, hours, and minutes: 1999-03-25T03:23-0500 */
  55   TIME_SPEC_MINUTES,
  56   /* display date, hours, minutes, and seconds: 1999-03-25T03:23:14-0500 */
  57   TIME_SPEC_SECONDS
  58 };
  59
  60 static char const *const time_spec_string[] =
  61 {
  62   "date", "hours", "minutes", "seconds", 0
  63 };
  64
  65 static enum Time_spec const time_spec[] =
  66 {
  67   TIME_SPEC_DATE, TIME_SPEC_HOURS, TIME_SPEC_MINUTES, TIME_SPEC_SECONDS
  68 };
  69
  70 /* The name this program was run with, for error messages. */
  71 char *program_name;
  72
  73 /* If nonzero, display an ISO 8601 format date/time string */
  74 static int iso_8601_format = 0;
  75
  76 /* If non-zero, display time in RFC-(2)822 format for mail or news. */
  77 static int rfc_format = 0;
  78
  79 #define COMMON_SHORT_OPTIONS "Rd:f:r:s:u"
  80
  81 static struct option const long_options[] =
  82 {
  83   {"date", required_argument, NULL, 'd'},
  84   {"file", required_argument, NULL, 'f'},
  85   {"iso-8601", optional_argument, NULL, 'I'},
  86   {"reference", required_argument, NULL, 'r'},
  87   {"rfc-822", no_argument, NULL, 'R'},
  88   {"set", required_argument, NULL, 's'},
  89   {"uct", no_argument, NULL, 'u'},
  90   {"utc", no_argument, NULL, 'u'},
  91   {"universal", no_argument, NULL, 'u'},
  92   {GETOPT_HELP_OPTION_DECL},
  93   {GETOPT_VERSION_OPTION_DECL},
  94   {NULL, 0, NULL, 0}
  95 };
  96
  97 #if LOCALTIME_CACHE
  98 # define TZSET tzset ()
  99 #else
 100 # define TZSET /* empty */
 101 #endif
 102
 103 #ifdef _DATE_FMT
 104 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
 105 #else
 106 # define DATE_FMT_LANGINFO() ""
 107 #endif
 108
 109 void
 110 usage (int status)
 111 {
 112   if (status != 0)
 113     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 114              program_name);
 115   else
 116     {
 117       printf (_("\
 118 Usage: %s [OPTION]... [+FORMAT]\n\
 119   or:  %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
 120 "),
 121               program_name, program_name);
 122       fputs (_("\
 123 Display the current time in the given FORMAT, or set the system date.\n\
 124 \n\
 125   -d, --date=STRING         display time described by STRING, not `now'\n\
 126   -f, --file=DATEFILE       like --date once for each line of DATEFILE\n\
 127   -ITIMESPEC, --iso-8601[=TIMESPEC]  output date/time in ISO 8601 format.\n\
 128                             TIMESPEC=`date' for date only,\n\
 129                             `hours', `minutes', or `seconds' for date and\n\
 130                             time to the indicated precision.\n\
 131                             --iso-8601 without TIMESPEC defaults to `date'.\n\
 132 "), stdout);
 133       fputs (_("\
 134   -r, --reference=FILE      display the last modification time of FILE\n\
 135   -R, --rfc-822             output RFC-822 compliant date string\n\
 136   -s, --set=STRING          set time described by STRING\n\
 137   -u, --utc, --universal    print or set Coordinated Universal Time\n\
 138 "), stdout);
 139       fputs (HELP_OPTION_DESCRIPTION, stdout);
 140       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 141       fputs (_("\
 142 \n\
 143 FORMAT controls the output.  The only valid option for the second form\n\
 144 specifies Coordinated Universal Time.  Interpreted sequences are:\n\
 145 \n\
 146   %%   a literal %\n\
 147   %a   locale's abbreviated weekday name (Sun..Sat)\n\
 148 "), stdout);
 149       fputs (_("\
 150   %A   locale's full weekday name, variable length (Sunday..Saturday)\n\
 151   %b   locale's abbreviated month name (Jan..Dec)\n\
 152   %B   locale's full month name, variable length (January..December)\n\
 153   %c   locale's date and time (Sat Nov 04 12:02:33 EST 1989)\n\
 154 "), stdout);
 155       fputs (_("\
 156   %C   century (year divided by 100 and truncated to an integer) [00-99]\n\
 157   %d   day of month (01..31)\n\
 158   %D   date (mm/dd/yy)\n\
 159   %e   day of month, blank padded ( 1..31)\n\
 160 "), stdout);
 161       fputs (_("\
 162   %F   same as %Y-%m-%d\n\
 163   %g   the 2-digit year corresponding to the %V week number\n\
 164   %G   the 4-digit year corresponding to the %V week number\n\
 165 "), stdout);
 166       fputs (_("\
 167   %h   same as %b\n\
 168   %H   hour (00..23)\n\
 169   %I   hour (01..12)\n\
 170   %j   day of year (001..366)\n\
 171 "), stdout);
 172       fputs (_("\
 173   %k   hour ( 0..23)\n\
 174   %l   hour ( 1..12)\n\
 175   %m   month (01..12)\n\
 176   %M   minute (00..59)\n\
 177 "), stdout);
 178       fputs (_("\
 179   %n   a newline\n\
 180   %N   nanoseconds (000000000..999999999)\n\
 181   %p   locale's upper case AM or PM indicator (blank in many locales)\n\
 182   %P   locale's lower case am or pm indicator (blank in many locales)\n\
 183   %r   time, 12-hour (hh:mm:ss [AP]M)\n\
 184   %R   time, 24-hour (hh:mm)\n\
 185   %s   seconds since `00:00:00 1970-01-01 UTC' (a GNU extension)\n\
 186 "), stdout);
 187       fputs (_("\
 188   %S   second (00..60); the 60 is necessary to accommodate a leap second\n\
 189   %t   a horizontal tab\n\
 190   %T   time, 24-hour (hh:mm:ss)\n\
 191   %u   day of week (1..7);  1 represents Monday\n\
 192 "), stdout);
 193       fputs (_("\
 194   %U   week number of year with Sunday as first day of week (00..53)\n\
 195   %V   week number of year with Monday as first day of week (01..53)\n\
 196   %w   day of week (0..6);  0 represents Sunday\n\
 197   %W   week number of year with Monday as first day of week (00..53)\n\
 198 "), stdout);
 199       fputs (_("\
 200   %x   locale's date representation (mm/dd/yy)\n\
 201   %X   locale's time representation (%H:%M:%S)\n\
 202   %y   last two digits of year (00..99)\n\
 203   %Y   year (1970...)\n\
 204 "), stdout);
 205       fputs (_("\
 206   %z   RFC-822 style numeric timezone (-0500) (a nonstandard extension)\n\
 207   %Z   time zone (e.g., EDT), or nothing if no time zone is determinable\n\
 208 \n\
 209 By default, date pads numeric fields with zeroes.  GNU date recognizes\n\
 210 the following modifiers between `%' and a numeric directive.\n\
 211 \n\
 212   `-' (hyphen) do not pad the field\n\
 213   `_' (underscore) pad the field with spaces\n\
 214 "), stdout);
 215       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
 216     }
 217   exit (status);
 218 }
 219
 220 /* Parse each line in INPUT_FILENAME as with --date and display each
 221    resulting time and date.  If the file cannot be opened, tell why
 222    then exit.  Issue a diagnostic for any lines that cannot be parsed.
 223    If any line cannot be parsed, return nonzero;  otherwise return zero.  */
 224
 225 static int
 226 batch_convert (const char *input_filename, const char *format)
 227 {
 228   int status;
 229   FILE *in_stream;
 230   char *line;
 231   int line_length;
 232   size_t buflen;
 233   struct timespec when;
 234
 235   if (strcmp (input_filename, "-") == 0)
 236     {
 237       input_filename = _("standard input");
 238       in_stream = stdin;
 239     }
 240   else
 241     {
 242       in_stream = fopen (input_filename, "r");
 243       if (in_stream == NULL)
 244         {
 245           error (EXIT_FAILURE, errno, "`%s'", input_filename);
 246         }
 247     }
 248
 249   line = NULL;
 250   buflen = 0;
 251   status = 0;
 252   while (1)
 253     {
 254       line_length = getline (&line, &buflen, in_stream);
 255       if (line_length < 0)
 256         {
 257           /* FIXME: detect/handle error here.  */
 258           break;
 259         }
 260
 261       when.tv_sec = get_date (line, NULL);
 262       when.tv_nsec = 0; /* FIXME: get_date should set this.  */
 263
 264       if (when.tv_sec == -1)
 265         {
 266           if (line[line_length - 1] == '\n')
 267             line[line_length - 1] = '\0';
 268           error (0, 0, _("invalid date `%s'"), line);
 269           status = 1;
 270         }
 271       else
 272         {
 273           show_date (format, when);
 274         }
 275     }
 276
 277   if (fclose (in_stream) == EOF)
 278     error (2, errno, "`%s'", input_filename);
 279
 280   if (line != NULL)
 281     free (line);
 282
 283   return status;
 284 }
 285
 286 int
 287 main (int argc, char **argv)
 288 {
 289   int optc;
 290   const char *datestr = NULL;
 291   const char *set_datestr = NULL;
 292   struct timespec when;
 293   int set_date = 0;
 294   char *format;
 295   char *batch_file = NULL;
 296   char *reference = NULL;
 297   struct stat refstats;
 298   int n_args;
 299   int status;
 300   int option_specified_date;
 301   char const *short_options = (posix2_version () < 200112
 302                                ? COMMON_SHORT_OPTIONS "I::"
 303                                : COMMON_SHORT_OPTIONS "I:");
 304
 305   program_name = argv[0];
 306   setlocale (LC_ALL, "");
 307   bindtextdomain (PACKAGE, LOCALEDIR);
 308   textdomain (PACKAGE);
 309
 310   close_stdout_set_status (2);
 311   atexit (close_stdout);
 312
 313   while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
 314          != -1)
 315     switch (optc)
 316       {
 317       case 0:
 318         break;
 319       case 'd':
 320         datestr = optarg;
 321         break;
 322       case 'f':
 323         batch_file = optarg;
 324         break;
 325       case 'I':
 326         iso_8601_format = (optarg
 327                            ? XARGMATCH ("--iso-8601", optarg,
 328                                         time_spec_string, time_spec)
 329                            : TIME_SPEC_DATE);
 330         break;
 331       case 'r':
 332         reference = optarg;
 333         break;
 334       case 'R':
 335         rfc_format = 1;
 336         break;
 337       case 's':
 338         set_datestr = optarg;
 339         set_date = 1;
 340         break;
 341       case 'u':
 342         /* POSIX says that `date -u' is equivalent to setting the TZ
 343            environment variable, so this option should do nothing other
 344            than setting TZ.  */
 345         if (putenv ("TZ=UTC0") != 0)
 346           xalloc_die ();
 347         TZSET;
 348         break;
 349       case_GETOPT_HELP_CHAR;
 350       case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 351       default:
 352         usage (EXIT_FAILURE);
 353       }
 354
 355   n_args = argc - optind;
 356
 357   option_specified_date = ((datestr ? 1 : 0)
 358                            + (batch_file ? 1 : 0)
 359                            + (reference ? 1 : 0));
 360
 361   if (option_specified_date > 1)
 362     {
 363       error (0, 0,
 364         _("the options to specify dates for printing are mutually exclusive"));
 365       usage (EXIT_FAILURE);
 366     }
 367
 368   if (set_date && option_specified_date)
 369     {
 370       error (0, 0,
 371           _("the options to print and set the time may not be used together"));
 372       usage (EXIT_FAILURE);
 373     }
 374
 375   if (n_args > 1)
 376     {
 377       error (0, 0, _("too many non-option arguments: %s%s"),
 378              argv[optind + 1], n_args == 2 ? "" : " ...");
 379       usage (EXIT_FAILURE);
 380     }
 381
 382   if ((set_date || option_specified_date)
 383       && n_args == 1 && argv[optind][0] != '+')
 384     {
 385       error (0, 0, _("\
 386 the argument `%s' lacks a leading `+';\n\
 387 When using an option to specify date(s), any non-option\n\
 388 argument must be a format string beginning with `+'."),
 389              argv[optind]);
 390       usage (EXIT_FAILURE);
 391     }
 392
 393   /* Simply ignore --rfc-822 if specified when setting the date.  */
 394   if (rfc_format && !set_date && n_args > 0)
 395     {
 396       error (0, 0,
 397              _("a format string may not be specified when using\
 398  the --rfc-822 (-R) option"));
 399       usage (EXIT_FAILURE);
 400     }
 401
 402   if (set_date)
 403     datestr = set_datestr;
 404
 405   if (batch_file != NULL)
 406     {
 407       status = batch_convert (batch_file,
 408                               (n_args == 1 ? argv[optind] + 1 : NULL));
 409     }
 410   else
 411     {
 412       bool valid_date = true;
 413       status = 0;
 414
 415       if (!option_specified_date && !set_date)
 416         {
 417           if (n_args == 1 && argv[optind][0] != '+')
 418             {
 419               /* Prepare to set system clock to the specified date/time
 420                  given in the POSIX-format.  */
 421               set_date = 1;
 422               datestr = argv[optind];
 423               valid_date = posixtime (&when.tv_sec,
 424                                       datestr,
 425                                       (PDS_TRAILING_YEAR
 426                                        | PDS_CENTURY | PDS_SECONDS));
 427               when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
 428               format = NULL;
 429             }
 430           else
 431             {
 432               /* Prepare to print the current date/time.  */
 433               datestr = _("undefined");
 434               if (gettime (&when) != 0)
 435                 error (EXIT_FAILURE, errno, _("cannot get time of day"));
 436               format = (n_args == 1 ? argv[optind] + 1 : NULL);
 437             }
 438         }
 439       else
 440         {
 441           /* (option_specified_date || set_date) */
 442           if (reference != NULL)
 443             {
 444               if (stat (reference, &refstats))
 445                 error (EXIT_FAILURE, errno, "%s", reference);
 446               when.tv_sec = refstats.st_mtime;
 447               when.tv_nsec = TIMESPEC_NS (refstats.st_mtim);
 448             }
 449           else
 450             {
 451               when.tv_sec = get_date (datestr, NULL);
 452               when.tv_nsec = 0; /* FIXME: get_date should set this.  */
 453               valid_date = (when.tv_sec != (time_t) -1);
 454             }
 455
 456           format = (n_args == 1 ? argv[optind] + 1 : NULL);
 457         }
 458
 459       if (! valid_date)
 460         error (EXIT_FAILURE, 0, _("invalid date `%s'"), datestr);
 461
 462       if (set_date)
 463         {
 464           /* Set the system clock to the specified date, then regardless of
 465              the success of that operation, format and print that date.  */
 466           if (settime (&when) != 0)
 467             {
 468               error (0, errno, _("cannot set date"));
 469               status = 1;
 470             }
 471         }
 472
 473       show_date (format, when);
 474     }
 475
 476   exit (status);
 477 }
 478
 479 /* Display the date and/or time in WHEN according to the format specified
 480    in FORMAT, followed by a newline.  If FORMAT is NULL, use the
 481    standard output format (ctime style but with a timezone inserted). */
 482
 483 static void
 484 show_date (const char *format, struct timespec when)
 485 {
 486   struct tm *tm;
 487   char *out = NULL;
 488   size_t out_length = 0;
 489   /* ISO 8601 formats.  See below regarding %z */
 490   static char const * const iso_format_string[] =
 491   {
 492     "%Y-%m-%d",
 493     "%Y-%m-%dT%H%z",
 494     "%Y-%m-%dT%H:%M%z",
 495     "%Y-%m-%dT%H:%M:%S%z"
 496   };
 497
 498   tm = localtime (&when.tv_sec);
 499
 500   if (format == NULL)
 501     {
 502       if (rfc_format)
 503         format = "%a, %d %b %Y %H:%M:%S %z";
 504       else if (iso_8601_format)
 505         format = iso_format_string[iso_8601_format - 1];
 506       else
 507         {
 508           char *date_fmt = DATE_FMT_LANGINFO ();
 509           /* Do not wrap the following literal format string with _(...).
 510              For example, suppose LC_ALL is unset, LC_TIME="POSIX",
 511              and LANG="ko_KR".  In that case, POSIX says that LC_TIME
 512              determines the format and contents of date and time strings
 513              written by date, which means "date" must generate output
 514              using the POSIX locale; but adding _() would cause "date"
 515              to use a Korean translation of the format.  */
 516           format = *date_fmt ? date_fmt : "%a %b %e %H:%M:%S %Z %Y";
 517         }
 518     }
 519   else if (*format == '\0')
 520     {
 521       printf ("\n");
 522       return;
 523     }
 524
 525   while (1)
 526     {
 527       int done;
 528       out_length += 200;
 529       out = (char *) xrealloc (out, out_length);
 530
 531       /* Mark the first byte of the buffer so we can detect the case
 532          of nstrftime producing an empty string.  Otherwise, this loop
 533          would not terminate when date was invoked like this
 534          `LANG=de date +%p' on a system with good language support.  */
 535       out[0] = '\1';
 536
 537       if (rfc_format)
 538         setlocale (LC_ALL, "C");
 539
 540       done = (nstrftime (out, out_length, format, tm, 0, when.tv_nsec)
 541               || out[0] == '\0');
 542
 543       if (rfc_format)
 544         setlocale (LC_ALL, "");
 545
 546       if (done)
 547         break;
 548     }
 549
 550   printf ("%s\n", out);
 551   free (out);
 552 }