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