coreutils/src/date.c

/* date - print or set the system date and time
   Copyright (C) 1989-2005 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

   David MacKenzie <djm@gnu.ai.mit.edu> */

#include <config.h>
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#if HAVE_LANGINFO_CODESET
# include <langinfo.h>
#endif

#include "system.h"
#include "argmatch.h"
#include "error.h"
#include "getdate.h"
#include "getline.h"
#include "inttostr.h"
#include "posixtm.h"
#include "quote.h"
#include "strftime.h"
#include "xanstrftime.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "date"

#define AUTHORS "David MacKenzie"

int putenv ();

static bool show_date (const char *format, struct timespec when);

enum Time_spec
{
  /* display only the date: 1999-03-25 */
  TIME_SPEC_DATE=1,
  /* display date and hour: 1999-03-25T03-0500 */
  TIME_SPEC_HOURS,
  /* display date, hours, and minutes: 1999-03-25T03:23-0500 */
  TIME_SPEC_MINUTES,
  /* display date, hours, minutes, and seconds: 1999-03-25T03:23:14-0500 */
  TIME_SPEC_SECONDS,
  /* similar, but display nanoseconds: 1999-03-25T03:23:14,123456789-0500 */
  TIME_SPEC_NS
};

static char const *const time_spec_string[] =
{
  "date", "hours", "minutes", "seconds", "ns", NULL
};
static enum Time_spec const time_spec[] =
{
  TIME_SPEC_DATE, TIME_SPEC_HOURS, TIME_SPEC_MINUTES, TIME_SPEC_SECONDS,
  TIME_SPEC_NS
};
ARGMATCH_VERIFY (time_spec_string, time_spec);

/* The name this program was run with, for error messages. */
char *program_name;

/* If nonzero, display an ISO 8601 format date/time string */
static int iso_8601_format = 0;

/* If true, display time in RFC-(2)822 format for mail or news. */
static bool rfc_format = false;

static char const short_options[] = "d:f:I::r:Rs:u";

static struct option const long_options[] =
{
  {"date", required_argument, NULL, 'd'},
  {"file", required_argument, NULL, 'f'},
  {"iso-8601", optional_argument, NULL, 'I'},
  {"reference", required_argument, NULL, 'r'},
  {"rfc-822", no_argument, NULL, 'R'},
  {"rfc-2822", no_argument, NULL, 'R'},
  {"set", required_argument, NULL, 's'},
  {"uct", no_argument, NULL, 'u'},
  {"utc", no_argument, NULL, 'u'},
  {"universal", no_argument, NULL, 'u'},
  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {NULL, 0, NULL, 0}
};

#if LOCALTIME_CACHE
# define TZSET tzset ()
#else
# define TZSET /* empty */
#endif

#ifdef _DATE_FMT
# define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
#else
# define DATE_FMT_LANGINFO() ""
#endif

void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("\
Usage: %s [OPTION]... [+FORMAT]\n\
  or:  %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
"),
	      program_name, program_name);
      fputs (_("\
Display the current time in the given FORMAT, or set the system date.\n\
\n\
  -d, --date=STRING         display time described by STRING, not `now'\n\
  -f, --file=DATEFILE       like --date once for each line of DATEFILE\n\
  -I[TIMESPEC], --iso-8601[=TIMESPEC]  output date/time in ISO 8601 format.\n\
                            TIMESPEC=`date' for date only (the default),\n\
                            `hours', `minutes', `seconds', or `ns' for date and\n\
                            time to the indicated precision.\n\
"), stdout);
      fputs (_("\
  -r, --reference=FILE      display the last modification time of FILE\n\
  -R, --rfc-2822            output RFC-2822 compliant date string\n\
  -s, --set=STRING          set time described by STRING\n\
  -u, --utc, --universal    print or set Coordinated Universal Time\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      fputs (_("\
\n\
FORMAT controls the output.  The only valid option for the second form\n\
specifies Coordinated Universal Time.  Interpreted sequences are:\n\
\n\
  %%   a literal %\n\
  %a   locale's abbreviated weekday name (e.g., Sun)\n\
"), stdout);
      fputs (_("\
  %A   locale's full weekday name (e.g., Sunday)\n\
  %b   locale's abbreviated month name (e.g., Jan)\n\
  %B   locale's full month name (e.g., January)\n\
  %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)\n\
"), stdout);
      fputs (_("\
  %C   century; like %Y, except omit last two digits (e.g., 21)\n\
  %d   day of month (e.g, 01)\n\
  %D   date; same as %m/%d/%y\n\
  %e   day of month, space padded; same as %_d\n\
"), stdout);
      fputs (_("\
  %F   full date; same as %Y-%m-%d\n\
  %g   the last two digits of the year corresponding to the %V week number\n\
  %G   the year corresponding to the %V week number\n\
"), stdout);
      fputs (_("\
  %h   same as %b\n\
  %H   hour (00..23)\n\
  %I   hour (01..12)\n\
  %j   day of year (001..366)\n\
"), stdout);
      fputs (_("\
  %k   hour ( 0..23)\n\
  %l   hour ( 1..12)\n\
  %m   month (01..12)\n\
  %M   minute (00..59)\n\
"), stdout);
      fputs (_("\
  %n   a newline\n\
  %N   nanoseconds (000000000..999999999)\n\
  %p   locale's equivalent of either AM or PM; blank if not known\n\
  %P   like %p, but lower case\n\
  %r   locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
  %R   24-hour hour and minute; same as %H:%M\n\
  %s   seconds since 1970-01-01 00:00:00 UTC\n\
"), stdout);
      fputs (_("\
  %S   second (00..60)\n\
  %t   a tab\n\
  %T   time; same as %H:%M:%S\n\
  %u   day of week (1..7); 1 is Monday\n\
"), stdout);
      fputs (_("\
  %U   week number of year with Sunday as first day of week (00..53)\n\
  %V   week number of year with Monday as first day of week (01..53)\n\
  %w   day of week (0..6); 0 is Sunday\n\
  %W   week number of year with Monday as first day of week (00..53)\n\
"), stdout);
      fputs (_("\
  %x   locale's date representation (e.g., 12/31/99)\n\
  %X   locale's time representation (e.g., 23:13:48)\n\
  %y   last two digits of year (00..99)\n\
  %Y   year\n\
"), stdout);
      fputs (_("\
  %z   numeric timezone (e.g., -0400)\n\
  %Z   alphabetic time zone abbreviation (e.g., EDT)\n\
\n\
By default, date pads numeric fields with zeroes.\n\
The following optional flags may follow `%':\n\
\n\
  - (hyphen) do not pad the field\n\
  _ (underscore) pad with spaces\n\
  0 (zero) pad with zeros\n\
  ^ use upper case if possible\n\
  # use opposite case if possible\n\
"), stdout);
      fputs (_("\
\n\
After any flags comes an optional field width, as a decimal number;\n\
then an optional modifier, which is either\n\
E to use the locale's alternate representations if available, or\n\
O to use the locale's alternate numeric symbols if available.\n\
"), stdout);
      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    }
  exit (status);
}

/* Parse each line in INPUT_FILENAME as with --date and display each
   resulting time and date.  If the file cannot be opened, tell why
   then exit.  Issue a diagnostic for any lines that cannot be parsed.
   Return true if successful.  */

static bool
batch_convert (const char *input_filename, const char *format)
{
  bool ok;
  FILE *in_stream;
  char *line;
  size_t buflen;
  struct timespec when;

  if (STREQ (input_filename, "-"))
    {
      input_filename = _("standard input");
      in_stream = stdin;
    }
  else
    {
      in_stream = fopen (input_filename, "r");
      if (in_stream == NULL)
	{
	  error (EXIT_FAILURE, errno, "%s", quote (input_filename));
	}
    }

  line = NULL;
  buflen = 0;
  ok = true;
  while (1)
    {
      ssize_t line_length = getline (&line, &buflen, in_stream);
      if (line_length < 0)
	{
	  /* FIXME: detect/handle error here.  */
	  break;
	}

      if (! get_date (&when, line, NULL))
	{
	  if (line[line_length - 1] == '\n')
	    line[line_length - 1] = '\0';
	  error (0, 0, _("invalid date %s"), quote (line));
	  ok = false;
	}
      else
	{
	  ok &= show_date (format, when);
	}
    }

  if (fclose (in_stream) == EOF)
    error (EXIT_FAILURE, errno, "%s", quote (input_filename));

  free (line);

  return ok;
}

int
main (int argc, char **argv)
{
  int optc;
  const char *datestr = NULL;
  const char *set_datestr = NULL;
  struct timespec when;
  bool set_date = false;
  char *format;
  char *batch_file = NULL;
  char *reference = NULL;
  struct stat refstats;
  int n_args;
  bool ok;
  int option_specified_date;

  initialize_main (&argc, &argv);
  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  atexit (close_stdout);

  while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
	 != -1)
    switch (optc)
      {
      case 'd':
	datestr = optarg;
	break;
      case 'f':
	batch_file = optarg;
	break;
      case 'I':
	iso_8601_format = (optarg
			   ? XARGMATCH ("--iso-8601", optarg,
					time_spec_string, time_spec)
			   : TIME_SPEC_DATE);
	break;
      case 'r':
	reference = optarg;
	break;
      case 'R':
	rfc_format = true;
	break;
      case 's':
	set_datestr = optarg;
	set_date = true;
	break;
      case 'u':
	/* POSIX says that `date -u' is equivalent to setting the TZ
	   environment variable, so this option should do nothing other
	   than setting TZ.  */
	if (putenv ("TZ=UTC0") != 0)
	  xalloc_die ();
	TZSET;
	break;
      case_GETOPT_HELP_CHAR;
      case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
      default:
	usage (EXIT_FAILURE);
      }

  n_args = argc - optind;

  option_specified_date = ((datestr ? 1 : 0)
			   + (batch_file ? 1 : 0)
			   + (reference ? 1 : 0));

  if (option_specified_date > 1)
    {
      error (0, 0,
	_("the options to specify dates for printing are mutually exclusive"));
      usage (EXIT_FAILURE);
    }

  if (set_date && option_specified_date)
    {
      error (0, 0,
	  _("the options to print and set the time may not be used together"));
      usage (EXIT_FAILURE);
    }

  if (n_args > 1)
    {
      error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
      usage (EXIT_FAILURE);
    }

  if ((set_date || option_specified_date)
      && n_args == 1 && argv[optind][0] != '+')
    {
      error (0, 0, _("\
the argument %s lacks a leading `+';\n\
When using an option to specify date(s), any non-option\n\
argument must be a format string beginning with `+'."),
	     quote (argv[optind]));
      usage (EXIT_FAILURE);
    }

  /* Simply ignore --rfc-2822 if specified when setting the date.  */
  if (rfc_format && !set_date && n_args > 0)
    {
      error (0, 0,
	     _("a format string may not be specified when using\
 the --rfc-2822 (-R) option"));
      usage (EXIT_FAILURE);
    }

  if (set_date)
    datestr = set_datestr;

  if (batch_file != NULL)
    ok = batch_convert (batch_file, (n_args == 1 ? argv[optind] + 1 : NULL));
  else
    {
      bool valid_date = true;
      ok = true;

      if (!option_specified_date && !set_date)
	{
	  if (n_args == 1 && argv[optind][0] != '+')
	    {
	      /* Prepare to set system clock to the specified date/time
		 given in the POSIX-format.  */
	      set_date = true;
	      datestr = argv[optind];
	      valid_date = posixtime (&when.tv_sec,
				      datestr,
				      (PDS_TRAILING_YEAR
				       | PDS_CENTURY | PDS_SECONDS));
	      when.tv_nsec = 0; /* FIXME: posixtime should set this.  */
	      format = NULL;
	    }
	  else
	    {
	      /* Prepare to print the current date/time.  */
	      datestr = _("undefined");
	      gettime (&when);
	      format = (n_args == 1 ? argv[optind] + 1 : NULL);
	    }
	}
      else
	{
	  /* (option_specified_date || set_date) */
	  if (reference != NULL)
	    {
	      if (stat (reference, &refstats))
		error (EXIT_FAILURE, errno, "%s", reference);
	      when.tv_sec = refstats.st_mtime;
	      when.tv_nsec = TIMESPEC_NS (refstats.st_mtim);
	    }
	  else
	    {
	      valid_date = get_date (&when, datestr, NULL);
	    }

	  format = (n_args == 1 ? argv[optind] + 1 : NULL);
	}

      if (! valid_date)
	error (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));

      if (set_date)
	{
	  /* Set the system clock to the specified date, then regardless of
	     the success of that operation, format and print that date.  */
	  if (settime (&when) != 0)
	    {
	      error (0, errno, _("cannot set date"));
	      ok = false;
	    }
	}

      ok &= show_date (format, when);
    }

  exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
}

/* Display the date and/or time in WHEN according to the format specified
   in FORMAT, followed by a newline.  If FORMAT is NULL, use the
   standard output format (ctime style but with a timezone inserted).
   Return true if successful.  */

static bool
show_date (const char *format, struct timespec when)
{
  struct tm *tm;
  /* ISO 8601 formats.  See below regarding %z */
  static char const * const iso_format_string[] =
  {
    "%Y-%m-%d",
    "%Y-%m-%dT%H%z",
    "%Y-%m-%dT%H:%M%z",
    "%Y-%m-%dT%H:%M:%S%z",
    "%Y-%m-%dT%H:%M:%S,%N%z"
  };

  if (format == NULL)
    {
      if (rfc_format)
	format = "%a, %d %b %Y %H:%M:%S %z";
      else if (iso_8601_format)
	format = iso_format_string[iso_8601_format - 1];
      else
	{
	  char *date_fmt = DATE_FMT_LANGINFO ();
	  /* Do not wrap the following literal format string with _(...).
	     For example, suppose LC_ALL is unset, LC_TIME="POSIX",
	     and LANG="ko_KR".	In that case, POSIX says that LC_TIME
	     determines the format and contents of date and time strings
	     written by date, which means "date" must generate output
	     using the POSIX locale; but adding _() would cause "date"
	     to use a Korean translation of the format.  */
	  format = *date_fmt ? date_fmt : "%a %b %e %H:%M:%S %Z %Y";
	}
    }

  tm = localtime (&when.tv_sec);
  if (! tm)
    {
      char buf[INT_BUFSIZE_BOUND (intmax_t)];
      error (0, 0, _("time %s is out of range"),
	     (TYPE_SIGNED (time_t)
	      ? imaxtostr (when.tv_sec, buf)
	      : umaxtostr (when.tv_sec, buf)));
      return false;
    }

  {
    char *out;

    if (rfc_format)
      setlocale (LC_TIME, "C");
    out = xanstrftime (format, tm, 0, when.tv_nsec);
    if (rfc_format)
      setlocale (LC_TIME, "");

    puts (out);
    free (out);
  }
  return true;
}