src/date.c

   1 /* date - print or set the system date and time
   2    Copyright (C) 89, 90, 91, 92, 93, 94, 1995 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
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, 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
  25 #include "system.h"
  26 #include "getline.h"
  27 #include "error.h"
  28
  29 #ifdef TM_IN_SYS_TIME
  30 #include <sys/time.h>
  31 #else
  32 #include <time.h>
  33 #endif
  34
  35 #ifndef STDC_HEADERS
  36 size_t strftime ();
  37 time_t time ();
  38 #endif
  39
  40 int putenv ();
  41 int stime ();
  42
  43 char *xrealloc ();
  44 time_t get_date ();
  45 time_t posixtime ();
  46
  47 static void show_date __P ((const char *format, time_t when));
  48 static void usage __P ((int status));
  49
  50 /* The name this program was run with, for error messages. */
  51 char *program_name;
  52
  53 /* If nonzero, display usage information and exit.  */
  54 static int show_help;
  55
  56 /* If nonzero, print the version on standard output and exit.  */
  57 static int show_version;
  58
  59 /* If non-zero, display time in RFC-822 format for mail or news. */
  60 static int rfc_format = 0;
  61
  62 /* If nonzero, print or set Coordinated Universal Time.  */
  63 static int universal_time = 0;
  64
  65 static struct option const long_options[] =
  66 {
  67   {"date", required_argument, NULL, 'd'},
  68   {"file", required_argument, NULL, 'f'},
  69   {"help", no_argument, &show_help, 1},
  70   {"reference", required_argument, NULL, 'r'},
  71   {"rfc-822", no_argument, NULL, 'R'},
  72   {"set", required_argument, NULL, 's'},
  73   {"uct", no_argument, NULL, 'u'},
  74   {"utc", no_argument, NULL, 'u'},
  75   {"universal", no_argument, NULL, 'u'},
  76   {"version", no_argument, &show_version, 1},
  77   {NULL, 0, NULL, 0}
  78 };
  79
  80 /* Parse each line in INPUT_FILENAME as with --date and display the
  81    each resulting time and date.  If the file cannot be opened, tell why
  82    then exit.  Issue a diagnostic for any lines that cannot be parsed.
  83    If any line cannot be parsed, return nonzero;  otherwise return zero.  */
  84
  85 static int
  86 batch_convert (const char *input_filename, const char *format)
  87 {
  88   int status;
  89   FILE *in_stream;
  90   char *line;
  91   int line_length;
  92   size_t buflen;
  93   time_t when;
  94
  95   if (strcmp (input_filename, "-") == 0)
  96     {
  97       input_filename = _("standard input");
  98       in_stream = stdin;
  99     }
 100   else
 101     {
 102       in_stream = fopen (input_filename, "r");
 103       if (in_stream == NULL)
 104         {
 105           error (1, errno, "`%s'", input_filename);
 106         }
 107     }
 108
 109   line = NULL;
 110   buflen = 0;
 111
 112   status = 0;
 113   while (1)
 114     {
 115       line_length = getline (&line, &buflen, in_stream);
 116       if (line_length < 0)
 117         {
 118           /* FIXME: detect/handle error here.  */
 119           break;
 120         }
 121       when = get_date (line, NULL);
 122       if (when == -1)
 123         {
 124           if (line[line_length - 1] == '\n')
 125             line[line_length - 1] = '\0';
 126           error (0, 0, _("invalid date `%s'"), line);
 127           status = 1;
 128         }
 129       else
 130         {
 131           show_date (format, when);
 132         }
 133     }
 134
 135   if (fclose (in_stream) == EOF)
 136     error (2, errno, input_filename);
 137
 138   if (line != NULL)
 139     free (line);
 140
 141   return status;
 142 }
 143
 144 void
 145 main (int argc, char **argv)
 146 {
 147   int optc;
 148   const char *datestr = NULL;
 149   const char *set_datestr = NULL;
 150   time_t when;
 151   int set_date = 0;
 152   char *format;
 153   char *batch_file = NULL;
 154   char *reference = NULL;
 155   struct stat refstats;
 156   int n_args;
 157   int status;
 158   int option_specified_date;
 159
 160   program_name = argv[0];
 161   setlocale (LC_ALL, "");
 162   bindtextdomain (PACKAGE, LOCALEDIR);
 163   textdomain (PACKAGE);
 164
 165   while ((optc = getopt_long (argc, argv, "d:f:r:Rs:u", long_options, NULL))
 166          != EOF)
 167     switch (optc)
 168       {
 169       case 0:
 170         break;
 171       case 'd':
 172         datestr = optarg;
 173         break;
 174       case 'f':
 175         batch_file = optarg;
 176         break;
 177       case 'r':
 178         reference = optarg;
 179         break;
 180       case 'R':
 181         rfc_format = 1;
 182         break;
 183       case 's':
 184         set_datestr = optarg;
 185         set_date = 1;
 186         break;
 187       case 'u':
 188         universal_time = 1;
 189         if (putenv ("TZ=UTC0") != 0)
 190           error (1, 0, "memory exhausted");
 191 #if LOCALTIME_CACHE
 192         tzset ();
 193 #endif
 194         break;
 195       default:
 196         usage (1);
 197       }
 198
 199   if (show_version)
 200     {
 201       printf ("date - %s\n", PACKAGE_VERSION);
 202       exit (0);
 203     }
 204
 205   if (show_help)
 206     usage (0);
 207
 208   n_args = argc - optind;
 209
 210   option_specified_date = ((datestr ? 1 : 0)
 211                            + (batch_file ? 1 : 0)
 212                            + (reference ? 1 : 0));
 213
 214   if (option_specified_date > 1)
 215     {
 216       error (0, 0,
 217         _("the options to specify dates for printing are mutually exclusive"));
 218       usage (1);
 219     }
 220
 221   if (set_date && option_specified_date)
 222     {
 223       error (0, 0,
 224           _("the options to print and set the time may not be used together"));
 225       usage (1);
 226     }
 227
 228   if (n_args > 1)
 229     {
 230       error (0, 0, _("too many non-option arguments"));
 231       usage (1);
 232     }
 233
 234   if ((set_date || option_specified_date)
 235       && n_args == 1 && argv[optind][0] != '+')
 236     {
 237       error (0, 0, _("\
 238 when using an option to specify date(s), any\n\
 239 non-option argument must be a format string beginning with `+'"));
 240       usage (1);
 241     }
 242
 243   if (set_date)
 244     datestr = set_datestr;
 245
 246   if (batch_file != NULL)
 247     {
 248       status = batch_convert (batch_file,
 249                               (n_args == 1 ? argv[optind] + 1 : NULL));
 250     }
 251   else
 252     {
 253       status = 0;
 254
 255       if (!option_specified_date && !set_date)
 256         {
 257           if (n_args == 1 && argv[optind][0] != '+')
 258             {
 259               /* Prepare to set system clock to the specified date/time
 260                  given in the POSIX-format.  */
 261               set_date = 1;
 262               datestr = argv[optind];
 263               when = posixtime (datestr);
 264               format = NULL;
 265             }
 266           else
 267             {
 268               /* Prepare to print the current date/time.  */
 269               datestr = _("undefined");
 270               time (&when);
 271               format = (n_args == 1 ? argv[optind] + 1 : NULL);
 272             }
 273         }
 274       else
 275         {
 276           /* (option_specified_date || set_date) */
 277           if (reference != NULL)
 278             {
 279               if (stat (reference, &refstats))
 280                 error (1, errno, "%s", reference);
 281               when = refstats.st_mtime;
 282             }
 283           else
 284             when = get_date (datestr, NULL);
 285           format = (n_args == 1 ? argv[optind] + 1 : NULL);
 286         }
 287
 288       if (when == -1)
 289         error (1, 0, _("invalid date `%s'"), datestr);
 290
 291       if (set_date)
 292         {
 293           /* Set the system clock to the specified date, then regardless of
 294              the success of that operation, format and print that date.  */
 295           if (stime (&when) == -1)
 296             error (0, errno, _("cannot set date"));
 297         }
 298
 299       show_date (format, when);
 300     }
 301
 302   if (fclose (stdout) == EOF)
 303     error (2, errno, _("write error"));
 304
 305   exit (status);
 306 }
 307
 308 /* Display the date and/or time in WHEN according to the format specified
 309    in FORMAT, followed by a newline.  If FORMAT is NULL, use the
 310    standard output format (ctime style but with a timezone inserted). */
 311
 312 static void
 313 show_date (const char *format, time_t when)
 314 {
 315   struct tm *tm;
 316   char *out = NULL;
 317   size_t out_length = 0;
 318
 319   tm = localtime (&when);
 320
 321   if (format == NULL)
 322     {
 323       /* Print the date in the default format.  Vanilla ANSI C strftime
 324          doesn't support %e, but POSIX requires it.  If you don't use
 325          a GNU strftime, make sure yours supports %e.
 326          If you are not using GNU strftime, you want to change %z
 327          in the RFC format to %Z; this gives, however, an invalid
 328          RFC time format outside the continental United States and GMT. */
 329
 330       format = (rfc_format
 331                 ? (universal_time
 332                    ? "%a, %_d %b %Y %H:%M:%S GMT"
 333                    : "%a, %_d %b %Y %H:%M:%S %z")
 334                 : "%a %b %e %H:%M:%S %Z %Y");
 335     }
 336   else if (*format == '\0')
 337     {
 338       printf ("\n");
 339       return;
 340     }
 341
 342   do
 343     {
 344       out_length += 200;
 345       out = (char *) xrealloc (out, out_length);
 346     }
 347   while (strftime (out, out_length, format, tm) == 0);
 348
 349   printf ("%s\n", out);
 350   free (out);
 351 }
 352
 353 static void
 354 usage (int status)
 355 {
 356   if (status != 0)
 357     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 358              program_name);
 359   else
 360     {
 361       printf (_("\
 362 Usage: %s [OPTION]... [+FORMAT]\n\
 363   or:  %s [OPTION] [MMDDhhmm[[CC]YY][.ss]]\n\
 364 "),
 365               program_name, program_name);
 366       printf (_("\
 367 Display the current time in the given FORMAT, or set the system date.\n\
 368 \n\
 369   -d, --date=STRING        display time described by STRING, not `now'\n\
 370   -f, --file=DATEFILE      like --date once for each line of DATEFILE\n\
 371   -r, --reference=FILE     display the last modification time of FILE\n\
 372   -R, --rfc-822            output RFC-822 compliant date string\n\
 373   -s, --set=STRING         set time described by STRING\n\
 374   -u, --utc, --universal   print or set Coordinated Universal Time\n\
 375       --help               display this help and exit\n\
 376       --version            output version information and exit\n\
 377 "));
 378       printf (_("\
 379 \n\
 380 FORMAT controls the output.  The only valid option for the second form\n\
 381 specifies Coordinated Universal Time.  Interpreted sequences are:\n\
 382 \n\
 383   %%%%   a literal %%\n\
 384   %%a   locale's abbreviated weekday name (Sun..Sat)\n\
 385   %%A   locale's full weekday name, variable length (Sunday..Saturday)\n\
 386   %%b   locale's abbreviated month name (Jan..Dec)\n\
 387   %%B   locale's full month name, variable length (January..December)\n\
 388   %%c   locale's date and time (Sat Nov 04 12:02:33 EST 1989)\n\
 389   %%d   day of month (01..31)\n\
 390   %%D   date (mm/dd/yy)\n\
 391   %%h   same as %%b\n\
 392   %%H   hour (00..23)\n\
 393   %%I   hour (01..12)\n\
 394   %%j   day of year (001..366)\n\
 395   %%k   hour ( 0..23)\n\
 396   %%l   hour ( 1..12)\n\
 397   %%m   month (01..12)\n\
 398   %%M   minute (00..59)\n\
 399   %%n   a newline\n\
 400   %%p   locale's AM or PM\n\
 401   %%r   time, 12-hour (hh:mm:ss [AP]M)\n\
 402   %%s   seconds since 00:00:00, Jan 1, 1970 (a GNU extension)\n\
 403   %%S   second (00..61)\n\
 404   %%t   a horizontal tab\n\
 405   %%T   time, 24-hour (hh:mm:ss)\n\
 406   %%U   week number of year with Sunday as first day of week (00..53)\n\
 407   %%w   day of week (0..6);  0 represents Sunday\n\
 408   %%W   week number of year with Monday as first day of week (00..53)\n\
 409   %%x   locale's date representation (mm/dd/yy)\n\
 410   %%X   locale's time representation (%%H:%%M:%%S)\n\
 411   %%y   last two digits of year (00..99)\n\
 412   %%Y   year (1970...)\n\
 413   %%Z   time zone (e.g., EDT), or nothing if no time zone is determinable\n\
 414 \n\
 415 By default, date pads numeric fields with zeroes.  GNU date recognizes\n\
 416 the following modifiers between `%%' and a numeric directive.\n\
 417 \n\
 418   `-' (hyphen) do not pad the field\n\
 419   `_' (underscore) pad the field with spaces\n\
 420 "));
 421     }
 422   exit (status);
 423 }