path: root/src/touch.c

/* touch -- change modification and access times of files
   Copyright (C) 87, 1989-1991, 1995-1999 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Written by Paul Rubin, Arnold Robbins, Jim Kingdon, David MacKenzie,
   and Randy Smith. */

#include <config.h>
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>

#include "system.h"
#include "argmatch.h"
#include "error.h"
#include "getdate.h"
#include "posixtm.h"
#include "safe-read.h"

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

#define AUTHORS \
  "Paul Rubin, Arnold Robbins, Jim Kingdon, David MacKenzie, and Randy Smith"

#ifndef STDC_HEADERS
time_t time ();
#endif

int full_write ();

/* Bitmasks for `change_times'. */
#define CH_ATIME 1
#define CH_MTIME 2

/* The name by which this program was run. */
char *program_name;

/* Which timestamps to change. */
static int change_times;

/* (-c) If nonzero, don't create if not already there. */
static int no_create;

/* (-d) If nonzero, date supplied on command line in get_date formats. */
static int flexible_date;

/* (-r) If nonzero, use times from a reference file. */
static int use_ref;

/* (-t) If nonzero, date supplied on command line in POSIX format. */
static int posix_date;

/* If nonzero, the only thing we have to do is change both the
   modification and access time to the current time, so we don't
   have to own the file, just be able to read and write it.  */
static int amtime_now;

/* New time to use when setting time. */
static time_t newtime;

/* File to use for -r. */
static char *ref_file;

/* Info about the reference file. */
static struct stat ref_stats;

static struct option const longopts[] =
{
  {"time", required_argument, 0, CHAR_MAX + 1},
  {"no-create", no_argument, 0, 'c'},
  {"date", required_argument, 0, 'd'},
  {"file", required_argument, 0, 'r'},
  {"reference", required_argument, 0, 'r'},
  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {0, 0, 0, 0}
};

/* Valid arguments to the `--time' option. */
static char const* const time_args[] =
{
  "atime", "access", "use", "mtime", "modify", 0
};

/* The bits in `change_times' that those arguments set. */
static int const time_masks[] =
{
  CH_ATIME, CH_ATIME, CH_ATIME, CH_MTIME, CH_MTIME
};

/* Open FILE, possibly creating it.  Set *FILE_CREATED to nonzero if the
   open creates it, or to zero if the open call opened an existing file.
   Return the result of the open call.  Be careful to avoid race conditions.  */

static int
open_maybe_create (const char *file, int *file_created)
{
  int fd;

  *file_created = 0;
  while (1)
    {
      /* First, see if we can create a new FILE.  */
      fd = open (file, O_WRONLY | O_CREAT | O_EXCL,
		 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
      if (fd != -1)
	*file_created = 1;

      /* If the open succeeded or if it failed for any reason other
	 than the existence of FILE, then we're done.  */
      if (fd != -1 || errno != EEXIST)
	break;

      /* The first open failed because FILE already exists.
	 Now try to open it for writing.  */
      fd = open (file, O_WRONLY);

      /* If the open succeeded or if it failed for any reason other
	 than the absence of FILE, then we're done.  */
      /* The 2nd open can fail if FILE was unlinked between the two
	 open calls.  When that happens, just iterate.  */
      if (fd != -1 || errno != ENOENT)
	break;
    }

  return fd;
}

/* Update the time of file FILE according to the options given.
   Return 0 if successful, 1 if an error occurs. */

static int
touch (const char *file)
{
  int status;
  struct stat sbuf;
  int fd;
  int file_created;

  if (no_create)
    {
      /* Try to open an existing FILE.  */
      fd = open (file, O_WRONLY);
      if (fd == -1 && errno == ENOENT)
	{
	  /* FILE doesn't exist.  So we're done.  */
	  return 0;
	}
      file_created = 0;
    }
  else
    {
      /* Try to open FILE, creating it if necessary.  */
      fd = open_maybe_create (file, &file_created);
    }

  if (fd == -1)
    {
      error (0, errno, "%s", file);
      return 1;
    }

  if (file_created && amtime_now)
    {
      if (close (fd) < 0)
	{
	  error (0, errno, "%s", file);
	  return 1;
	}
      return 0;		/* We've done all we have to. */
    }

  if (fstat (fd, &sbuf))
    {
      error (0, errno, "%s", file);
      close (fd);
      return 1;
    }

  if (close (fd) < 0)
    {
      error (0, errno, "%s", file);
      return 1;
    }

  if (amtime_now)
    {
      /* Pass NULL to utime so it will not fail if we just have
	 write access to the file, but don't own it.  */
      status = utime (file, NULL);
    }
  else
    {
      struct utimbuf utb;

      /* There's currently no interface to set file timestamps with
	 better than 1-second resolution, so discard any fractional
	 part of the source timestamp.  */

      if (use_ref)
	{
	  utb.actime = ref_stats.st_atime;
	  utb.modtime = ref_stats.st_mtime;
	}
      else
	utb.actime = utb.modtime = newtime;

      if (!(change_times & CH_ATIME))
	utb.actime = sbuf.st_atime;

      if (!(change_times & CH_MTIME))
	utb.modtime = sbuf.st_mtime;

      status = utime (file, &utb);
    }

  if (status)
    {
      error (0, errno, "%s", file);
      return 1;
    }

  return 0;
}

void
usage (int status)
{
  if (status != 0)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("Usage: %s [OPTION]... FILE...\n"), program_name);
      printf (_("  or : %s [-acm] MMDDhhmm[YY] FILE... (obsolescent)\n"),
	      program_name);
      printf (_("\
Update the access and modification times of each FILE to the current time.\n\
\n\
  -a                     change only the access time\n\
  -c                     do not create any files\n\
  -d, --date=STRING      parse STRING and use it instead of current time\n\
  -f                     (ignored)\n\
  -m                     change only the modification time\n\
  -r, --reference=FILE   use this file's times instead of current time\n\
  -t STAMP               use [[CC]YY]MMDDhhmm[.ss] instead of current time\n\
      --time=WORD        access -a, atime -a, mtime -m, modify -m, use -a\n\
      --help             display this help and exit\n\
      --version          output version information and exit\n\
\n\
STAMP may be used without -t if none of -drt, nor --, are used.\n\
Note that the three time-date formats recognized for the -d and -t options\n\
and for the obsolescent argument are all different.\n\
"));
      puts (_("\nReport bugs to <bug-fileutils@gnu.org>."));
      close_stdout ();
    }
  exit (status);
}

int
main (int argc, char **argv)
{
  int c;
  int date_set = 0;
  int err = 0;

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

  change_times = no_create = use_ref = posix_date = flexible_date = 0;
  newtime = (time_t) -1;

  while ((c = getopt_long (argc, argv, "acd:fmr:t:", longopts, NULL)) != -1)
    {
      switch (c)
	{
	case 0:
	  break;

	case 'a':
	  change_times |= CH_ATIME;
	  break;

	case 'c':
	  no_create++;
	  break;

	case 'd':
	  flexible_date++;
	  newtime = get_date (optarg, NULL);
	  if (newtime == (time_t) -1)
	    error (1, 0, _("invalid date format `%s'"), optarg);
	  date_set++;
	  break;

	case 'f':
	  break;

	case 'm':
	  change_times |= CH_MTIME;
	  break;

	case 'r':
	  use_ref++;
	  ref_file = optarg;
	  break;

	case 't':
	  posix_date++;
	  newtime = posixtime (optarg,
			       PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS);
	  if (newtime == (time_t) -1)
	    error (1, 0, _("invalid date format `%s'"), optarg);
	  date_set++;
	  break;

	case CHAR_MAX + 1:	/* --time */
	  change_times |= XARGMATCH ("--time", optarg,
				     time_args, time_masks);
	  break;

	case_GETOPT_HELP_CHAR;

	case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

	default:
	  usage (1);
	}
    }

  if (change_times == 0)
    change_times = CH_ATIME | CH_MTIME;

  if ((use_ref && (posix_date || flexible_date))
      || (posix_date && flexible_date))
    {
      error (0, 0, _("cannot specify times from more than one source"));
      usage (1);
    }

  if (use_ref)
    {
      if (stat (ref_file, &ref_stats))
	error (1, errno, "%s", ref_file);
      date_set++;
    }

  if (!date_set && optind < argc && !STREQ (argv[optind - 1], "--"))
    {
      newtime = posixtime (argv[optind], PDS_TRAILING_YEAR);
      if (newtime != (time_t) -1)
	{
	  optind++;
	  date_set++;
	}
    }
  if (!date_set)
    {
      if ((change_times & (CH_ATIME | CH_MTIME)) == (CH_ATIME | CH_MTIME))
	amtime_now = 1;
      else
	time (&newtime);
    }

  if (optind == argc)
    {
      error (0, 0, _("file arguments missing"));
      usage (1);
    }

  for (; optind < argc; ++optind)
    err += touch (argv[optind]);

  exit (err != 0);
}