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 non-zero, display usage information and exit.  */
  54 static int show_help;
  55
  56 /* If non-zero, print the version on standard output and exit.  */
  57 static int show_version;
  58
  59 /* If non-zero, 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   {"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 /* Parse each line in INPUT_FILENAME as with --date and display the
  76    each resulting time and date.  If the file cannot be opened, tell why
  77    then exit.  Issue a diagnostic for any lines that cannot be parsed.
  78    If any line cannot be parsed, return non-zero;  otherwise return zero.  */
  79
  80 static int
  81 batch_convert (input_filename, format)
  82      const char *input_filename;
  83      const char *format;
  84 {
  85   int have_read_stdin;
  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       have_read_stdin = 1;
  98     }
  99   else
 100     {
 101       in_stream = fopen (input_filename, "r");
 102       if (in_stream == NULL)
 103         {
 104           error (0, errno, "%s", input_filename);
 105         }
 106       have_read_stdin = 0;
 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 (have_read_stdin && fclose (stdin) == EOF)
 136     error (2, errno, "standard input");
 137
 138   if (line != NULL)
 139     free (line);
 140
 141   return status;
 142 }
 143
 144 void
 145 main (argc, argv)
 146      int argc;
 147      char **argv;
 148 {
 149   int optc;
 150   const char *datestr = NULL;
 151   time_t when;
 152   int set_date = 0;
 153   int print_date = 0;
 154   char *format;
 155   char *batch_file = NULL;
 156   int n_args;
 157   int status;
 158
 159   program_name = argv[0];
 160
 161   while ((optc = getopt_long (argc, argv, "d:f:s:u", long_options, (int *) 0))
 162          != EOF)
 163     switch (optc)
 164       {
 165       case 0:
 166         break;
 167       case 'd':
 168         datestr = optarg;
 169         print_date = 1;
 170         break;
 171       case 'f':
 172         batch_file = optarg;
 173         break;
 174       case 's':
 175         datestr = optarg;
 176         set_date = 1;
 177         break;
 178       case 'u':
 179         universal_time = 1;
 180         break;
 181       default:
 182         usage (1);
 183       }
 184
 185   if (show_version)
 186     {
 187       printf ("date - %s\n", version_string);
 188       exit (0);
 189     }
 190
 191   if (show_help)
 192     usage (0);
 193
 194   n_args = argc - optind;
 195
 196   if (set_date && print_date)
 197     {
 198       error (0, 0,
 199           "the options to print and set the time may not be used together");
 200       usage (1);
 201     }
 202
 203   if (n_args > 1)
 204     {
 205       error (0, 0, "too many non-option arguments");
 206       usage (1);
 207     }
 208
 209   if ((set_date || print_date || batch_file != NULL)
 210       && n_args == 1 && argv[optind][0] != '+')
 211     {
 212       error (0, 0, "\
 213 when using the print, set time, or batch options, any\n\
 214 non-option argument must be a format string beginning with `+'");
 215       usage (1);
 216     }
 217
 218   if (batch_file != NULL)
 219     {
 220       if (set_date || print_date)
 221         {
 222           error (0, 0, "\
 223 neither print nor set options may be used when reading dates from a file");
 224           usage (1);
 225         }
 226       status = batch_convert (batch_file,
 227                               (n_args == 1 ? argv[optind] + 1 : NULL));
 228     }
 229   else
 230     {
 231       status = 0;
 232
 233       if (!print_date && !set_date)
 234         {
 235           if (n_args == 1 && argv[optind][0] != '+')
 236             {
 237               /* Prepare to set system clock to the specified date/time
 238                  given in the POSIX-format.  */
 239               set_date = 1;
 240               datestr = argv[optind];
 241               when = posixtime (datestr);
 242               format = NULL;
 243             }
 244           else
 245             {
 246               /* Prepare to print the current date/time.  */
 247               print_date = 1;
 248               datestr = "undefined";
 249               time (&when);
 250               format = (n_args == 1 ? argv[optind] + 1 : NULL);
 251             }
 252         }
 253       else
 254         {
 255           /* (print_date || set_date) */
 256           when = get_date (datestr, NULL);
 257           format = (n_args == 1 ? argv[optind] + 1 : NULL);
 258         }
 259
 260       if (when == -1)
 261         error (1, 0, "invalid date `%s'", datestr);
 262
 263       if (set_date)
 264         {
 265           /* Set the system clock to the specified date, then regardless of
 266              the success of that operation, format and print that date.  */
 267           if (stime (&when) == -1)
 268             error (0, errno, "cannot set date");
 269         }
 270
 271       show_date (format, when);
 272     }
 273
 274   if (fclose (stdout) == EOF)
 275     error (2, errno, "write error");
 276
 277   exit (status);
 278 }
 279
 280 /* Display the date and/or time in WHEN according to the format specified
 281    in FORMAT, followed by a newline.  If FORMAT is NULL, use the
 282    standard output format (ctime style but with a timezone inserted). */
 283
 284 static void
 285 show_date (format, when)
 286      const char *format;
 287      time_t when;
 288 {
 289   struct tm *tm;
 290   char *out = NULL;
 291   size_t out_length = 0;
 292
 293   tm = (universal_time ? gmtime : localtime) (&when);
 294
 295   if (format == NULL)
 296     {
 297       /* Print the date in the default format.  Vanilla ANSI C strftime
 298          doesn't support %e, but POSIX requires it.  If you don't use
 299          a GNU strftime, make sure yours supports %e.  */
 300       format = (universal_time
 301                 ? "%a %b %e %H:%M:%S UTC %Y"
 302                 : "%a %b %e %H:%M:%S %Z %Y");
 303     }
 304   else if (*format == '\0')
 305     {
 306       printf ("\n");
 307       return;
 308     }
 309
 310   do
 311     {
 312       out_length += 200;
 313       out = (char *) xrealloc (out, out_length);
 314     }
 315   while (strftime (out, out_length, format, tm) == 0);
 316
 317   printf ("%s\n", out);
 318   free (out);
 319 }
 320
 321 static void
 322 usage (status)
 323      int status;
 324 {
 325   if (status != 0)
 326     fprintf (stderr, "Try `%s --help' for more information.\n",
 327              program_name);
 328   else
 329     {
 330       printf ("\
 331 Usage: %s [OPTION]... [+FORMAT]\n\
 332   or:  %s [OPTION] [MMDDhhmm[[CC]YY][.ss]]\n\
 333 ",
 334               program_name, program_name);
 335       printf ("\
 336 Display the current time in the given FORMAT, or set the system date.\n\
 337 \n\
 338   -d, --date=STRING        display time described by STRING, not `now'\n\
 339   -f, --file=DATEFILE      like --date once for each line of DATEFILE\n\
 340   -s, --set=STRING         set time described by STRING\n\
 341   -u, --utc, --universal   print or set Coordinated Universal Time\n\
 342       --help               display this help and exit\n\
 343       --version            output version information and exit\n\
 344 ");
 345       printf ("\
 346 \n\
 347 FORMAT controls the output.  The only valid option for the second form\n\
 348 specifies Coordinated Universal Time.  Interpreted sequences are:\n\
 349 \n\
 350   %%%%   a literal %%\n\
 351   %%a   locale's abbreviated weekday name (Sun..Sat)\n\
 352   %%A   locale's full weekday name, variable length (Sunday..Saturday)\n\
 353   %%b   locale's abbreviated month name (Jan..Dec)\n\
 354   %%B   locale's full month name, variable length (January..December)\n\
 355   %%c   locale's date and time (Sat Nov 04 12:02:33 EST 1989)\n\
 356   %%d   day of month (01..31)\n\
 357   %%D   date (mm/dd/yy)\n\
 358   %%h   same as %%b\n\
 359   %%H   hour (00..23)\n\
 360   %%I   hour (01..12)\n\
 361   %%j   day of year (001..366)\n\
 362   %%k   hour ( 0..23)\n\
 363   %%l   hour ( 1..12)\n\
 364   %%m   month (01..12)\n\
 365   %%M   minute (00..59)\n\
 366   %%n   a newline\n\
 367   %%p   locale's AM or PM\n\
 368   %%r   time, 12-hour (hh:mm:ss [AP]M)\n\
 369   %%s   seconds since 00:00:00, Jan 1, 1970 (a GNU extension)\n\
 370   %%S   second (00..61)\n\
 371   %%t   a horizontal tab\n\
 372   %%T   time, 24-hour (hh:mm:ss)\n\
 373   %%U   week number of year with Sunday as first day of week (00..53)\n\
 374   %%w   day of week (0..6);  0 represents Sunday\n\
 375   %%W   week number of year with Monday as first day of week (00..53)\n\
 376   %%x   locale's date representation (mm/dd/yy)\n\
 377   %%X   locale's time representation (%%H:%%M:%%S)\n\
 378   %%y   last two digits of year (00..99)\n\
 379   %%Y   year (1970...)\n\
 380   %%Z   time zone (e.g., EDT), or nothing if no time zone is determinable\n\
 381 \n\
 382 By default, date pads numeric fields with zeroes.  GNU date recognizes\n\
 383 the following modifiers between `%%' and a numeric directive.\n\
 384 \n\
 385   `-' (hyphen) do not pad the field\n\
 386   `_' (underscore) pad the field with spaces\n\
 387 ");
 388     }
 389   exit (status);
 390 }