src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 89, 90, 91, 92, 93, 94, 95, 96, 1997
   3    Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18
  19    David MacKenzie <djm@gnu.ai.mit.edu> */
  20
  21 #include <config.h>
  22 #include <stdio.h>
  23 #include <getopt.h>
  24 #include <sys/types.h>
  25
  26 #include "system.h"
  27 #include "getline.h"
  28 #include "error.h"
  29 #include "getdate.h"
  30
  31 #ifndef STDC_HEADERS
  32 size_t strftime ();
  33 time_t time ();
  34 #endif
  35
  36 int putenv ();
  37 int stime ();
  38
  39 char *xstrdup ();
  40 time_t posixtime ();
  41
  42 static void show_date PARAMS ((const char *format, time_t when));
  43 static void usage PARAMS ((int status));
  44
  45 /* The name this program was run with, for error messages. */
  46 char *program_name;
  47
  48 /* If nonzero, display usage information and exit.  */
  49 static int show_help;
  50
  51 /* If nonzero, print the version on standard output and exit.  */
  52 static int show_version;
  53
  54 /* If non-zero, display time in RFC-822 format for mail or news. */
  55 static int rfc_format = 0;
  56
  57 /* If nonzero, print or set Coordinated Universal Time.  */
  58 static int universal_time = 0;
  59
  60 static struct option const long_options[] =
  61 {
  62   {"date", required_argument, NULL, 'd'},
  63   {"file", required_argument, NULL, 'f'},
  64   {"help", no_argument, &show_help, 1},
  65   {"reference", required_argument, NULL, 'r'},
  66   {"rfc-822", no_argument, NULL, 'R'},
  67   {"set", required_argument, NULL, 's'},
  68   {"uct", no_argument, NULL, 'u'},
  69   {"utc", no_argument, NULL, 'u'},
  70   {"universal", no_argument, NULL, 'u'},
  71   {"version", no_argument, &show_version, 1},
  72   {NULL, 0, NULL, 0}
  73 };
  74
  75 #define TZ_UTC0 "TZ=UTC0"
  76
  77 #if LOCALTIME_CACHE
  78 # define TZSET tzset ()
  79 #else
  80 # define TZSET /* empty */
  81 #endif
  82
  83 #define MAYBE_SET_TZ_UTC0 \
  84   do { if (universal_time) set_tz (TZ_UTC0); } while (0)
  85
  86 /* Set the TZ environment variable.  */
  87
  88 static void
  89 set_tz (const char *tz_eq_zone)
  90 {
  91   if (putenv (tz_eq_zone) != 0)
  92     error (1, 0, "memory exhausted");
  93   TZSET;
  94 }
  95
  96 /* Parse each line in INPUT_FILENAME as with --date and display each
  97    resulting time and date.  If the file cannot be opened, tell why
  98    then exit.  Issue a diagnostic for any lines that cannot be parsed.
  99    If any line cannot be parsed, return nonzero;  otherwise return zero.  */
 100
 101 static int
 102 batch_convert (const char *input_filename, const char *format)
 103 {
 104   int status;
 105   FILE *in_stream;
 106   char *line;
 107   int line_length;
 108   size_t buflen;
 109   time_t when;
 110   char *initial_TZ;
 111
 112 #ifdef lint
 113   /* Suppress `may be used before initialized' warning.  */
 114   initial_TZ = NULL;
 115 #endif
 116
 117   if (strcmp (input_filename, "-") == 0)
 118     {
 119       input_filename = _("standard input");
 120       in_stream = stdin;
 121     }
 122   else
 123     {
 124       in_stream = fopen (input_filename, "r");
 125       if (in_stream == NULL)
 126         {
 127           error (1, errno, "`%s'", input_filename);
 128         }
 129     }
 130
 131   line = NULL;
 132   buflen = 0;
 133
 134   if (universal_time)
 135     {
 136       initial_TZ = getenv ("TZ");
 137       if (initial_TZ == NULL)
 138         {
 139           initial_TZ = xstrdup ("TZ=");
 140         }
 141       else
 142         {
 143           size_t tz_len = strlen (initial_TZ);
 144           char *buf = xmalloc (3 + tz_len + 1);
 145           memcpy (mempcpy (buf, "TZ=", 3), initial_TZ, tz_len + 1);
 146           initial_TZ = buf;
 147         }
 148     }
 149
 150   status = 0;
 151   while (1)
 152     {
 153       line_length = getline (&line, &buflen, in_stream);
 154       if (line_length < 0)
 155         {
 156           /* FIXME: detect/handle error here.  */
 157           break;
 158         }
 159
 160       if (universal_time)
 161         {
 162           /* When given a universal time option, restore the initial
 163              value of TZ before parsing each string.  */
 164           set_tz (initial_TZ);
 165         }
 166
 167       when = get_date (line, NULL);
 168
 169       if (when == -1)
 170         {
 171           if (line[line_length - 1] == '\n')
 172             line[line_length - 1] = '\0';
 173           error (0, 0, _("invalid date ` %s'"), line);
 174           status = 1;
 175         }
 176       else
 177         {
 178           MAYBE_SET_TZ_UTC0;
 179           show_date (format, when);
 180         }
 181     }
 182
 183   free (initial_TZ);
 184
 185   if (fclose (in_stream) == EOF)
 186     error (2, errno, input_filename);
 187
 188   if (line != NULL)
 189     free (line);
 190
 191   return status;
 192 }
 193
 194 int
 195 main (int argc, char **argv)
 196 {
 197   int optc;
 198   const char *datestr = NULL;
 199   const char *set_datestr = NULL;
 200   time_t when;
 201   int set_date = 0;
 202   char *format;
 203   char *batch_file = NULL;
 204   char *reference = NULL;
 205   struct stat refstats;
 206   int n_args;
 207   int status;
 208   int option_specified_date;
 209
 210   program_name = argv[0];
 211   setlocale (LC_ALL, "");
 212   bindtextdomain (PACKAGE, LOCALEDIR);
 213   textdomain (PACKAGE);
 214
 215   while ((optc = getopt_long (argc, argv, "d:f:r:Rs:u", long_options, NULL))
 216          != -1)
 217     switch (optc)
 218       {
 219       case 0:
 220         break;
 221       case 'd':
 222         datestr = optarg;
 223         break;
 224       case 'f':
 225         batch_file = optarg;
 226         break;
 227       case 'r':
 228         reference = optarg;
 229         break;
 230       case 'R':
 231         rfc_format = 1;
 232         break;
 233       case 's':
 234         set_datestr = optarg;
 235         set_date = 1;
 236         break;
 237       case 'u':
 238         universal_time = 1;
 239         break;
 240       default:
 241         usage (1);
 242       }
 243
 244   if (show_version)
 245     {
 246       printf ("date (%s) %s\n", GNU_PACKAGE, VERSION);
 247       exit (0);
 248     }
 249
 250   if (show_help)
 251     usage (0);
 252
 253   n_args = argc - optind;
 254
 255   option_specified_date = ((datestr ? 1 : 0)
 256                            + (batch_file ? 1 : 0)
 257                            + (reference ? 1 : 0));
 258
 259   if (option_specified_date > 1)
 260     {
 261       error (0, 0,
 262         _("the options to specify dates for printing are mutually exclusive"));
 263       usage (1);
 264     }
 265
 266   if (set_date && option_specified_date)
 267     {
 268       error (0, 0,
 269           _("the options to print and set the time may not be used together"));
 270       usage (1);
 271     }
 272
 273   if (n_args > 1)
 274     {
 275       error (0, 0, _("too many non-option arguments"));
 276       usage (1);
 277     }
 278
 279   if ((set_date || option_specified_date)
 280       && n_args == 1 && argv[optind][0] != '+')
 281     {
 282       error (0, 0, _("\
 283 the argument `%s' lacks a leading `+';\n\
 284 When using an option to specify date(s), any non-option\n\
 285 argument must be a format string beginning with `+'."),
 286              argv[optind]);
 287       usage (1);
 288     }
 289
 290   if (set_date)
 291     datestr = set_datestr;
 292
 293   if (batch_file != NULL)
 294     {
 295       status = batch_convert (batch_file,
 296                               (n_args == 1 ? argv[optind] + 1 : NULL));
 297     }
 298   else
 299     {
 300       status = 0;
 301
 302       if (!option_specified_date && !set_date)
 303         {
 304           if (n_args == 1 && argv[optind][0] != '+')
 305             {
 306               /* Prepare to set system clock to the specified date/time
 307                  given in the POSIX-format.  */
 308               set_date = 1;
 309               datestr = argv[optind];
 310               when = posixtime (datestr);
 311               format = NULL;
 312             }
 313           else
 314             {
 315               /* Prepare to print the current date/time.  */
 316               datestr = _("undefined");
 317               time (&when);
 318               format = (n_args == 1 ? argv[optind] + 1 : NULL);
 319             }
 320         }
 321       else
 322         {
 323           /* (option_specified_date || set_date) */
 324           if (reference != NULL)
 325             {
 326               if (stat (reference, &refstats))
 327                 error (1, errno, "%s", reference);
 328               when = refstats.st_mtime;
 329             }
 330           else
 331             {
 332               when = get_date (datestr, NULL);
 333             }
 334
 335           format = (n_args == 1 ? argv[optind] + 1 : NULL);
 336         }
 337
 338       if (when == -1)
 339         error (1, 0, _("invalid date `%s'"), datestr);
 340
 341       if (set_date)
 342         {
 343           /* Set the system clock to the specified date, then regardless of
 344              the success of that operation, format and print that date.  */
 345           if (stime (&when) == -1)
 346             error (0, errno, _("cannot set date"));
 347         }
 348
 349       /* When given a universal time option, set TZ to UTC0 after
 350          parsing the specified date, but before printing it.  */
 351       MAYBE_SET_TZ_UTC0;
 352
 353       show_date (format, when);
 354     }
 355
 356   if (fclose (stdout) == EOF)
 357     error (2, errno, _("write error"));
 358
 359   exit (status);
 360 }
 361
 362 /* Display the date and/or time in WHEN according to the format specified
 363    in FORMAT, followed by a newline.  If FORMAT is NULL, use the
 364    standard output format (ctime style but with a timezone inserted). */
 365
 366 static void
 367 show_date (const char *format, time_t when)
 368 {
 369   struct tm *tm;
 370   char *out = NULL;
 371   size_t out_length = 0;
 372
 373   tm = localtime (&when);
 374
 375   if (format == NULL)
 376     {
 377       /* Print the date in the default format.  Vanilla ANSI C strftime
 378          doesn't support %e, but POSIX requires it.  If you don't use
 379          a GNU strftime, make sure yours supports %e.
 380          If you are not using GNU strftime, you want to change %z
 381          in the RFC format to %Z; this gives, however, an invalid
 382          RFC time format outside the continental United States and GMT. */
 383
 384       format = (rfc_format
 385                 ? (universal_time
 386                    ? "%a, %_d %b %Y %H:%M:%S GMT"
 387                    : "%a, %_d %b %Y %H:%M:%S %z")
 388                 : "%a %b %e %H:%M:%S %Z %Y");
 389     }
 390   else if (*format == '\0')
 391     {
 392       printf ("\n");
 393       return;
 394     }
 395
 396   do
 397     {
 398       out_length += 200;
 399       out = (char *) xrealloc (out, out_length);
 400
 401       /* Mark the first byte of the buffer so we can detect the case
 402          of strftime producing an empty string.  Otherwise, this loop
 403          would not terminate when date was invoked like this
 404          `LANG=de date +%p' on a system with good language support.  */
 405       out[0] = '\1';
 406     }
 407   while (strftime (out, out_length, format, tm) == 0 && out[0] != '\0');
 408
 409   printf ("%s\n", out);
 410   free (out);
 411 }
 412
 413 static void
 414 usage (int status)
 415 {
 416   if (status != 0)
 417     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 418              program_name);
 419   else
 420     {
 421       printf (_("\
 422 Usage: %s [OPTION]... [+FORMAT]\n\
 423   or:  %s [OPTION] [MMDDhhmm[[CC]YY][.ss]]\n\
 424 "),
 425               program_name, program_name);
 426       printf (_("\
 427 Display the current time in the given FORMAT, or set the system date.\n\
 428 \n\
 429   -d, --date=STRING        display time described by STRING, not `now'\n\
 430   -f, --file=DATEFILE      like --date once for each line of DATEFILE\n\
 431   -r, --reference=FILE     display the last modification time of FILE\n\
 432   -R, --rfc-822            output RFC-822 compliant date string\n\
 433   -s, --set=STRING         set time described by STRING\n\
 434   -u, --utc, --universal   print or set Coordinated Universal Time\n\
 435       --help               display this help and exit\n\
 436       --version            output version information and exit\n\
 437 "));
 438       printf (_("\
 439 \n\
 440 FORMAT controls the output.  The only valid option for the second form\n\
 441 specifies Coordinated Universal Time.  Interpreted sequences are:\n\
 442 \n\
 443   %%%%   a literal %%\n\
 444   %%a   locale's abbreviated weekday name (Sun..Sat)\n\
 445   %%A   locale's full weekday name, variable length (Sunday..Saturday)\n\
 446   %%b   locale's abbreviated month name (Jan..Dec)\n\
 447   %%B   locale's full month name, variable length (January..December)\n\
 448   %%c   locale's date and time (Sat Nov 04 12:02:33 EST 1989)\n\
 449   %%d   day of month (01..31)\n\
 450   %%D   date (mm/dd/yy)\n\
 451   %%e   day of month, blank padded ( 1..31)\n\
 452   %%h   same as %%b\n\
 453   %%H   hour (00..23)\n\
 454   %%I   hour (01..12)\n\
 455   %%j   day of year (001..366)\n\
 456   %%k   hour ( 0..23)\n\
 457   %%l   hour ( 1..12)\n\
 458   %%m   month (01..12)\n\
 459   %%M   minute (00..59)\n\
 460   %%n   a newline\n\
 461   %%p   locale's AM or PM\n\
 462   %%r   time, 12-hour (hh:mm:ss [AP]M)\n\
 463   %%s   seconds since 00:00:00, Jan 1, 1970 (a GNU extension)\n\
 464   %%S   second (00..61)\n\
 465   %%t   a horizontal tab\n\
 466   %%T   time, 24-hour (hh:mm:ss)\n\
 467   %%U   week number of year with Sunday as first day of week (00..53)\n\
 468   %%V   week number of year with Monday as first day of week (01..52)\n\
 469   %%w   day of week (0..6);  0 represents Sunday\n\
 470   %%W   week number of year with Monday as first day of week (00..53)\n\
 471   %%x   locale's date representation (mm/dd/yy)\n\
 472   %%X   locale's time representation (%%H:%%M:%%S)\n\
 473   %%y   last two digits of year (00..99)\n\
 474   %%Y   year (1970...)\n\
 475   %%z   RFC-822 style numeric timezone (-0500) (a nonstandard extension)\n\
 476   %%Z   time zone (e.g., EDT), or nothing if no time zone is determinable\n\
 477 \n\
 478 By default, date pads numeric fields with zeroes.  GNU date recognizes\n\
 479 the following modifiers between `%%' and a numeric directive.\n\
 480 \n\
 481   `-' (hyphen) do not pad the field\n\
 482   `_' (underscore) pad the field with spaces\n\
 483 "));
 484       puts (_("\nReport bugs to <sh-utils-bugs@gnu.org>."));
 485     }
 486   exit (status);
 487 }