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 #include "posixtm.h"
  31
  32 #ifndef STDC_HEADERS
  33 size_t strftime ();
  34 time_t time ();
  35 #endif
  36
  37 int putenv ();
  38 int stime ();
  39
  40 char *xstrdup ();
  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                                 PDS_TRAILING_YEAR | PDS_CENTURY | PDS_SECONDS);
 312               format = NULL;
 313             }
 314           else
 315             {
 316               /* Prepare to print the current date/time.  */
 317               datestr = _("undefined");
 318               time (&when);
 319               format = (n_args == 1 ? argv[optind] + 1 : NULL);
 320             }
 321         }
 322       else
 323         {
 324           /* (option_specified_date || set_date) */
 325           if (reference != NULL)
 326             {
 327               if (stat (reference, &refstats))
 328                 error (1, errno, "%s", reference);
 329               when = refstats.st_mtime;
 330             }
 331           else
 332             {
 333               when = get_date (datestr, NULL);
 334             }
 335
 336           format = (n_args == 1 ? argv[optind] + 1 : NULL);
 337         }
 338
 339       if (when == -1)
 340         error (1, 0, _("invalid date `%s'"), datestr);
 341
 342       if (set_date)
 343         {
 344           /* Set the system clock to the specified date, then regardless of
 345              the success of that operation, format and print that date.  */
 346           if (stime (&when) == -1)
 347             error (0, errno, _("cannot set date"));
 348         }
 349
 350       /* When given a universal time option, set TZ to UTC0 after
 351          parsing the specified date, but before printing it.  */
 352       MAYBE_SET_TZ_UTC0;
 353
 354       show_date (format, when);
 355     }
 356
 357   if (fclose (stdout) == EOF)
 358     error (2, errno, _("write error"));
 359
 360   exit (status);
 361 }
 362
 363 /* Display the date and/or time in WHEN according to the format specified
 364    in FORMAT, followed by a newline.  If FORMAT is NULL, use the
 365    standard output format (ctime style but with a timezone inserted). */
 366
 367 static void
 368 show_date (const char *format, time_t when)
 369 {
 370   struct tm *tm;
 371   char *out = NULL;
 372   size_t out_length = 0;
 373
 374   tm = localtime (&when);
 375
 376   if (format == NULL)
 377     {
 378       /* Print the date in the default format.  Vanilla ANSI C strftime
 379          doesn't support %e, but POSIX requires it.  If you don't use
 380          a GNU strftime, make sure yours supports %e.
 381          If you are not using GNU strftime, you want to change %z
 382          in the RFC format to %Z; this gives, however, an invalid
 383          RFC time format outside the continental United States and GMT. */
 384
 385       format = (rfc_format
 386                 ? (universal_time
 387                    ? "%a, %_d %b %Y %H:%M:%S GMT"
 388                    : "%a, %_d %b %Y %H:%M:%S %z")
 389                 : "%a %b %e %H:%M:%S %Z %Y");
 390     }
 391   else if (*format == '\0')
 392     {
 393       printf ("\n");
 394       return;
 395     }
 396
 397   do
 398     {
 399       out_length += 200;
 400       out = (char *) xrealloc (out, out_length);
 401
 402       /* Mark the first byte of the buffer so we can detect the case
 403          of strftime producing an empty string.  Otherwise, this loop
 404          would not terminate when date was invoked like this
 405          `LANG=de date +%p' on a system with good language support.  */
 406       out[0] = '\1';
 407     }
 408   while (strftime (out, out_length, format, tm) == 0 && out[0] != '\0');
 409
 410   printf ("%s\n", out);
 411   free (out);
 412 }
 413
 414 static void
 415 usage (int status)
 416 {
 417   if (status != 0)
 418     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 419              program_name);
 420   else
 421     {
 422       printf (_("\
 423 Usage: %s [OPTION]... [+FORMAT]\n\
 424   or:  %s [OPTION] [MMDDhhmm[[CC]YY][.ss]]\n\
 425 "),
 426               program_name, program_name);
 427       printf (_("\
 428 Display the current time in the given FORMAT, or set the system date.\n\
 429 \n\
 430   -d, --date=STRING        display time described by STRING, not `now'\n\
 431   -f, --file=DATEFILE      like --date once for each line of DATEFILE\n\
 432   -r, --reference=FILE     display the last modification time of FILE\n\
 433   -R, --rfc-822            output RFC-822 compliant date string\n\
 434   -s, --set=STRING         set time described by STRING\n\
 435   -u, --utc, --universal   print or set Coordinated Universal Time\n\
 436       --help               display this help and exit\n\
 437       --version            output version information and exit\n\
 438 "));
 439       printf (_("\
 440 \n\
 441 FORMAT controls the output.  The only valid option for the second form\n\
 442 specifies Coordinated Universal Time.  Interpreted sequences are:\n\
 443 \n\
 444   %%%%   a literal %%\n\
 445   %%a   locale's abbreviated weekday name (Sun..Sat)\n\
 446   %%A   locale's full weekday name, variable length (Sunday..Saturday)\n\
 447   %%b   locale's abbreviated month name (Jan..Dec)\n\
 448   %%B   locale's full month name, variable length (January..December)\n\
 449   %%c   locale's date and time (Sat Nov 04 12:02:33 EST 1989)\n\
 450   %%d   day of month (01..31)\n\
 451   %%D   date (mm/dd/yy)\n\
 452   %%e   day of month, blank padded ( 1..31)\n\
 453   %%h   same as %%b\n\
 454   %%H   hour (00..23)\n\
 455   %%I   hour (01..12)\n\
 456   %%j   day of year (001..366)\n\
 457   %%k   hour ( 0..23)\n\
 458   %%l   hour ( 1..12)\n\
 459   %%m   month (01..12)\n\
 460   %%M   minute (00..59)\n\
 461   %%n   a newline\n\
 462   %%p   locale's AM or PM\n\
 463   %%r   time, 12-hour (hh:mm:ss [AP]M)\n\
 464   %%s   seconds since 00:00:00, Jan 1, 1970 (a GNU extension)\n\
 465   %%S   second (00..61)\n\
 466   %%t   a horizontal tab\n\
 467   %%T   time, 24-hour (hh:mm:ss)\n\
 468   %%U   week number of year with Sunday as first day of week (00..53)\n\
 469   %%V   week number of year with Monday as first day of week (01..52)\n\
 470   %%w   day of week (0..6);  0 represents Sunday\n\
 471   %%W   week number of year with Monday as first day of week (00..53)\n\
 472   %%x   locale's date representation (mm/dd/yy)\n\
 473   %%X   locale's time representation (%%H:%%M:%%S)\n\
 474   %%y   last two digits of year (00..99)\n\
 475   %%Y   year (1970...)\n\
 476   %%z   RFC-822 style numeric timezone (-0500) (a nonstandard extension)\n\
 477   %%Z   time zone (e.g., EDT), or nothing if no time zone is determinable\n\
 478 \n\
 479 By default, date pads numeric fields with zeroes.  GNU date recognizes\n\
 480 the following modifiers between `%%' and a numeric directive.\n\
 481 \n\
 482   `-' (hyphen) do not pad the field\n\
 483   `_' (underscore) pad the field with spaces\n\
 484 "));
 485       puts (_("\nReport bugs to <bug-sh-utils@gnu.org>."));
 486     }
 487   exit (status);
 488 }