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_H
  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 "timespec.h"
  37
  38 /* The official name of this program (e.g., no `g' prefix).  */
  39 #define PROGRAM_NAME "date"
  40
  41 #define AUTHORS "David MacKenzie"
  42
  43 int putenv ();
  44
  45 size_t nstrftime PARAMS ((char *, size_t, char const *,
  46                           struct tm const *, int, int));
  47
  48 static void show_date PARAMS ((const char *format, struct timespec when));
  49
  50 enum Time_spec
  51 {
  52   /* display only the date: 1999-03-25 */
  53   TIME_SPEC_DATE=1,
  54   /* display date and hour: 1999-03-25T03-0500 */
  55   TIME_SPEC_HOURS,
  56   /* display date, hours, and minutes: 1999-03-25T03:23-0500 */
  57   TIME_SPEC_MINUTES,
  58   /* display date, hours, minutes, and seconds: 1999-03-25T03:23:14-0500 */
  59   TIME_SPEC_SECONDS
  60 };
  61
  62 static char const *const time_spec_string[] =
  63 {
  64   "date", "hours", "minutes", "seconds", 0
  65 };
  66
  67 static enum Time_spec const time_spec[] =
  68 {
  69   TIME_SPEC_DATE, TIME_SPEC_HOURS, TIME_SPEC_MINUTES, TIME_SPEC_SECONDS
  70 };
  71
  72 /* The name this program was run with, for error messages. */
  73 char *program_name;
  74
  75 /* If nonzero, display an ISO 8601 format date/time string */
  76 static int iso_8601_format = 0;
  77
  78 /* If non-zero, display time in RFC-(2)822 format for mail or news. */
  79 static int rfc_format = 0;
  80
  81 #define COMMON_SHORT_OPTIONS "Rd:f:r:s:u"
  82
  83 static struct option const long_options[] =
  84 {
  85   {"date", required_argument, NULL, 'd'},
  86   {"file", required_argument, NULL, 'f'},
  87   {"iso-8601", optional_argument, NULL, 'I'},
  88   {"reference", required_argument, NULL, 'r'},
  89   {"rfc-822", no_argument, NULL, 'R'},
  90   {"set", required_argument, NULL, 's'},
  91   {"uct", no_argument, NULL, 'u'},
  92   {"utc", no_argument, NULL, 'u'},
  93   {"universal", no_argument, NULL, 'u'},
  94   {GETOPT_HELP_OPTION_DECL},
  95   {GETOPT_VERSION_OPTION_DECL},
  96   {NULL, 0, NULL, 0}
  97 };
  98
  99 #if LOCALTIME_CACHE
 100 # define TZSET tzset ()
 101 #else
 102 # define TZSET /* empty */
 103 #endif
 104
 105 #ifdef _DATE_FMT
 106 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
 107 #else
 108 # define DATE_FMT_LANGINFO() ""
 109 #endif
 110
 111 void
 112 usage (int status)
 113 {
 114   if (status != 0)
 115     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 116              program_name);
 117   else
 118     {
 119       printf (_("\
 120 Usage: %s [OPTION]... [+FORMAT]\n\
 121   or:  %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
 122 "),
 123               program_name, program_name);
 124       fputs (_("\
 125 Display the current time in the given FORMAT, or set the system date.\n\
 126 \n\
 127   -d, --date=STRING         display time described by STRING, not `now'\n\
 128   -f, --file=DATEFILE       like --date once for each line of DATEFILE\n\
 129   -ITIMESPEC, --iso-8601[=TIMESPEC]  output date/time in ISO 8601 format.\n\
 130                             TIMESPEC=`date' for date only,\n\
 131                             `hours', `minutes', or `seconds' for date and\n\
 132                             time to the indicated precision.\n\
 133                             --iso-8601 without TIMESPEC defaults to `date'.\n\
 134 "), stdout);
 135       fputs (_("\
 136   -r, --reference=FILE      display the last modification time of FILE\n\
 137   -R, --rfc-822             output RFC-822 compliant date string\n\
 138   -s, --set=STRING          set time described by STRING\n\
 139   -u, --utc, --universal    print or set Coordinated Universal Time\n\
 140 "), stdout);
 141       fputs (HELP_OPTION_DESCRIPTION, stdout);
 142       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 143       fputs (_("\
 144 \n\
 145 FORMAT controls the output.  The only valid option for the second form\n\
 146 specifies Coordinated Universal Time.  Interpreted sequences are:\n\
 147 \n\
 148   %%   a literal %\n\
 149   %a   locale's abbreviated weekday name (Sun..Sat)\n\
 150 "), stdout);
 151       fputs (_("\
 152   %A   locale's full weekday name, variable length (Sunday..Saturday)\n\
 153   %b   locale's abbreviated month name (Jan..Dec)\n\
 154   %B   locale's full month name, variable length (January..December)\n\
 155   %c   locale's date and time (Sat Nov 04 12:02:33 EST 1989)\n\
 156 "), stdout);
 157       fputs (_("\
 158   %C   century (year divided by 100 and truncated to an integer) [00-99]\n\
 159   %d   day of month (01..31)\n\
 160   %D   date (mm/dd/yy)\n\
 161   %e   day of month, blank padded ( 1..31)\n\
 162 "), stdout);
 163       fputs (_("\
 164   %F   same as %Y-%m-%d\n\
 165   %g   the 2-digit year corresponding to the %V week number\n\
 166   %G   the 4-digit year corresponding to the %V week number\n\
 167 "), stdout);
 168       fputs (_("\
 169   %h   same as %b\n\
 170   %H   hour (00..23)\n\
 171   %I   hour (01..12)\n\
 172   %j   day of year (001..366)\n\
 173 "), stdout);
 174       fputs (_("\
 175   %k   hour ( 0..23)\n\
 176   %l   hour ( 1..12)\n\
 177   %m   month (01..12)\n\
 178   %M   minute (00..59)\n\
 179 "), stdout);
 180       fputs (_("\
 181   %n   a newline\n\
 182   %N   nanoseconds (000000000..999999999)\n\
 183   %p   locale's upper case AM or PM indicator (blank in many locales)\n\
 184   %P   locale's lower case am or pm indicator (blank in many locales)\n\
 185   %r   time, 12-hour (hh:mm:ss [AP]M)\n\
 186   %R   time, 24-hour (hh:mm)\n\
 187   %s   seconds since `00:00:00 1970-01-01 UTC' (a GNU extension)\n\
 188 "), stdout);
 189       fputs (_("\
 190   %S   second (00..60)\n\
 191   %t   a horizontal tab\n\
 192   %T   time, 24-hour (hh:mm:ss)\n\
 193   %u   day of week (1..7);  1 represents Monday\n\
 194 "), stdout);
 195       fputs (_("\
 196   %U   week number of year with Sunday as first day of week (00..53)\n\
 197   %V   week number of year with Monday as first day of week (01..53)\n\
 198   %w   day of week (0..6);  0 represents Sunday\n\
 199   %W   week number of year with Monday as first day of week (00..53)\n\
 200 "), stdout);
 201       fputs (_("\
 202   %x   locale's date representation (mm/dd/yy)\n\
 203   %X   locale's time representation (%H:%M:%S)\n\
 204   %y   last two digits of year (00..99)\n\
 205   %Y   year (1970...)\n\
 206 "), stdout);
 207       fputs (_("\
 208   %z   RFC-822 style numeric timezone (-0500) (a nonstandard extension)\n\
 209   %Z   time zone (e.g., EDT), or nothing if no time zone is determinable\n\
 210 \n\
 211 By default, date pads numeric fields with zeroes.  GNU date recognizes\n\
 212 the following modifiers between `%' and a numeric directive.\n\
 213 \n\
 214   `-' (hyphen) do not pad the field\n\
 215   `_' (underscore) pad the field with spaces\n\
 216 "), stdout);
 217       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
 218     }
 219   exit (status);
 220 }
 221
 222 /* Parse each line in INPUT_FILENAME as with --date and display each
 223    resulting time and date.  If the file cannot be opened, tell why
 224    then exit.  Issue a diagnostic for any lines that cannot be parsed.
 225    If any line cannot be parsed, return nonzero;  otherwise return zero.  */
 226
 227 static int
 228 batch_convert (const char *input_filename, const char *format)
 229 {
 230   int status;
 231   FILE *in_stream;
 232   char *line;
 233   int line_length;
 234   size_t buflen;
 235   struct timespec when;
 236
 237   if (strcmp (input_filename, "-") == 0)
 238     {
 239       input_filename = _("standard input");
 240       in_stream = stdin;
 241     }
 242   else
 243     {
 244       in_stream = fopen (input_filename, "r");
 245       if (in_stream == NULL)
 246         {
 247           error (1, errno, "`%s'", input_filename);
 248         }
 249     }
 250
 251   line = NULL;
 252   buflen = 0;
 253   status = 0;
 254   while (1)
 255     {
 256       line_length = getline (&line, &buflen, in_stream);
 257       if (line_length < 0)
 258         {
 259           /* FIXME: detect/handle error here.  */
 260           break;
 261         }
 262
 263       when.tv_sec = get_date (line, NULL);
 264       when.tv_nsec = 0; /* FIXME: get_date should set this.  */
 265
 266       if (when.tv_sec == -1)
 267         {
 268           if (line[line_length - 1] == '\n')
 269             line[line_length - 1] = '\0';
 270           error (0, 0, _("invalid date `%s'"), line);
 271           status = 1;
 272         }
 273       else
 274         {
 275           show_date (format, when);
 276         }
 277     }
 278
 279   if (fclose (in_stream) == EOF)
 280     error (2, errno, "`%s'", input_filename);
 281
 282   if (line != NULL)
 283     free (line);
 284
 285   return status;
 286 }
 287
 288 int
 289 main (int argc, char **argv)
 290 {
 291   int optc;
 292   const char *datestr = NULL;
 293   const char *set_datestr = NULL;
 294   struct timespec when;
 295   int set_date = 0;
 296   char *format;
 297   char *batch_file = NULL;
 298   char *reference = NULL;
 299   struct stat refstats;
 300   int n_args;
 301   int status;
 302   int option_specified_date;
 303   char const *short_options = (posix2_version () < 200112
 304                                ? COMMON_SHORT_OPTIONS "I::"
 305                                : COMMON_SHORT_OPTIONS "I:");
 306
 307   program_name = argv[0];
 308   setlocale (LC_ALL, "");
 309   bindtextdomain (PACKAGE, LOCALEDIR);
 310   textdomain (PACKAGE);
 311
 312   close_stdout_set_status (2);
 313   atexit (close_stdout);
 314
 315   while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
 316          != -1)
 317     switch (optc)
 318       {
 319       case 0:
 320         break;
 321       case 'd':
 322         datestr = optarg;
 323         break;
 324       case 'f':
 325         batch_file = optarg;
 326         break;
 327       case 'I':
 328         iso_8601_format = (optarg
 329                            ? XARGMATCH ("--iso-8601", optarg,
 330                                         time_spec_string, time_spec)
 331                            : TIME_SPEC_DATE);
 332         break;
 333       case 'r':
 334         reference = optarg;
 335         break;
 336       case 'R':
 337         rfc_format = 1;
 338         break;
 339       case 's':
 340         set_datestr = optarg;
 341         set_date = 1;
 342         break;
 343       case 'u':
 344         /* POSIX says that `date -u' is equivalent to setting the TZ
 345            environment variable, so this option should do nothing other
 346            than setting TZ.  */
 347         if (putenv ("TZ=UTC0") != 0)
 348           xalloc_die ();
 349         TZSET;
 350         break;
 351       case_GETOPT_HELP_CHAR;
 352       case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 353       default:
 354         usage (1);
 355       }
 356
 357   n_args = argc - optind;
 358
 359   option_specified_date = ((datestr ? 1 : 0)
 360                            + (batch_file ? 1 : 0)
 361                            + (reference ? 1 : 0));
 362
 363   if (option_specified_date > 1)
 364     {
 365       error (0, 0,
 366         _("the options to specify dates for printing are mutually exclusive"));
 367       usage (1);
 368     }
 369
 370   if (set_date && option_specified_date)
 371     {
 372       error (0, 0,
 373           _("the options to print and set the time may not be used together"));
 374       usage (1);
 375     }
 376
 377   if (n_args > 1)
 378     {
 379       error (0, 0, _("too many non-option arguments: %s%s"),
 380              argv[optind + 1], n_args == 2 ? "" : " ...");
 381       usage (1);
 382     }
 383
 384   if ((set_date || option_specified_date)
 385       && n_args == 1 && argv[optind][0] != '+')
 386     {
 387       error (0, 0, _("\
 388 the argument `%s' lacks a leading `+';\n\
 389 When using an option to specify date(s), any non-option\n\
 390 argument must be a format string beginning with `+'."),
 391              argv[optind]);
 392       usage (1);
 393     }
 394
 395   /* Simply ignore --rfc-822 if specified when setting the date.  */
 396   if (rfc_format && !set_date && n_args > 0)
 397     {
 398       error (0, 0,
 399              _("a format string may not be specified when using\
 400  the --rfc-822 (-R) option"));
 401       usage (1);
 402     }
 403
 404   if (set_date)
 405     datestr = set_datestr;
 406
 407   if (batch_file != NULL)
 408     {
 409       status = batch_convert (batch_file,
 410                               (n_args == 1 ? argv[optind] + 1 : NULL));
 411     }
 412   else
 413     {
 414       bool valid_date = true;
 415       status = 0;
 416
 417       if (!option_specified_date && !set_date)
 418         {
 419           if (n_args == 1 && argv[optind][0] != '+')
 420             {
 421               /* Prepare to set system clock to the specified date/time
 422                  given in the POSIX-format.  */
 423               set_date = 1;
 424               datestr = argv[optind];
 425               valid_date = posixtime (&when.tv_sec,
 426                                       datestr,
 427                                       (PDS_TRAILING_YEAR
 428                                        | PDS_CENTURY | PDS_SECONDS));
 429               when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
 430               format = NULL;
 431             }
 432           else
 433             {
 434               /* Prepare to print the current date/time.  */
 435               datestr = _("undefined");
 436               if (gettime (&when) != 0)
 437                 error (EXIT_FAILURE, errno, _("cannot get time of day"));
 438               format = (n_args == 1 ? argv[optind] + 1 : NULL);
 439             }
 440         }
 441       else
 442         {
 443           /* (option_specified_date || set_date) */
 444           if (reference != NULL)
 445             {
 446               if (stat (reference, &refstats))
 447                 error (1, errno, "%s", reference);
 448               when.tv_sec = refstats.st_mtime;
 449               when.tv_nsec = TIMESPEC_NS (refstats.st_mtim);
 450             }
 451           else
 452             {
 453               when.tv_sec = get_date (datestr, NULL);
 454               when.tv_nsec = 0; /* FIXME: get_date should set this.  */
 455               valid_date = (when.tv_sec != (time_t) -1);
 456             }
 457
 458           format = (n_args == 1 ? argv[optind] + 1 : NULL);
 459         }
 460
 461       if (! valid_date)
 462         error (1, 0, _("invalid date `%s'"), datestr);
 463
 464       if (set_date)
 465         {
 466           /* Set the system clock to the specified date, then regardless of
 467              the success of that operation, format and print that date.  */
 468           if (settime (&when) != 0)
 469             {
 470               error (0, errno, _("cannot set date"));
 471               status = 1;
 472             }
 473         }
 474
 475       show_date (format, when);
 476     }
 477
 478   exit (status);
 479 }
 480
 481 /* Display the date and/or time in WHEN according to the format specified
 482    in FORMAT, followed by a newline.  If FORMAT is NULL, use the
 483    standard output format (ctime style but with a timezone inserted). */
 484
 485 static void
 486 show_date (const char *format, struct timespec when)
 487 {
 488   struct tm *tm;
 489   char *out = NULL;
 490   size_t out_length = 0;
 491   /* ISO 8601 formats.  See below regarding %z */
 492   static char const * const iso_format_string[] =
 493   {
 494     "%Y-%m-%d",
 495     "%Y-%m-%dT%H%z",
 496     "%Y-%m-%dT%H:%M%z",
 497     "%Y-%m-%dT%H:%M:%S%z"
 498   };
 499
 500   tm = localtime (&when.tv_sec);
 501
 502   if (format == NULL)
 503     {
 504       if (rfc_format)
 505         format = "%a, %d %b %Y %H:%M:%S %z";
 506       else if (iso_8601_format)
 507         format = iso_format_string[iso_8601_format - 1];
 508       else
 509         {
 510           char *date_fmt = DATE_FMT_LANGINFO ();
 511           /* Do not wrap the following literal format string with _(...).
 512              For example, suppose LC_ALL is unset, LC_TIME="POSIX",
 513              and LANG="ko_KR".  In that case, POSIX says that LC_TIME
 514              determines the format and contents of date and time strings
 515              written by date, which means "date" must generate output
 516              using the POSIX locale; but adding _() would cause "date"
 517              to use a Korean translation of the format.  */
 518           format = *date_fmt ? date_fmt : "%a %b %e %H:%M:%S %Z %Y";
 519         }
 520     }
 521   else if (*format == '\0')
 522     {
 523       printf ("\n");
 524       return;
 525     }
 526
 527   while (1)
 528     {
 529       int done;
 530       out_length += 200;
 531       out = (char *) xrealloc (out, out_length);
 532
 533       /* Mark the first byte of the buffer so we can detect the case
 534          of nstrftime producing an empty string.  Otherwise, this loop
 535          would not terminate when date was invoked like this
 536          `LANG=de date +%p' on a system with good language support.  */
 537       out[0] = '\1';
 538
 539       if (rfc_format)
 540         setlocale (LC_ALL, "C");
 541
 542       done = (nstrftime (out, out_length, format, tm, 0, when.tv_nsec)
 543               || out[0] == '\0');
 544
 545       if (rfc_format)
 546         setlocale (LC_ALL, "");
 547
 548       if (done)
 549         break;
 550     }
 551
 552   printf ("%s\n", out);
 553   free (out);
 554 }