coreutils/lib/utimens.c

/* Copyright (C) 2003, 2004, 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.  */

/* Written by Paul Eggert.  */

/* derived from a function in touch.c */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "utimens.h"

#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#if HAVE_UTIME_H
# include <utime.h>
#endif

/* Some systems (even some that do have <utime.h>) don't declare this
   structure anywhere.  */
#ifndef HAVE_STRUCT_UTIMBUF
struct utimbuf
{
  long actime;
  long modtime;
};
#endif

/* Some systems don't have ENOSYS.  */
#ifndef ENOSYS
# ifdef ENOTSUP
#  define ENOSYS ENOTSUP
# else
/* Some systems don't have ENOTSUP either.  */
#  define ENOSYS EINVAL
# endif
#endif

#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
# define __attribute__(x)
#endif

#ifndef ATTRIBUTE_UNUSED
# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
#endif

/* Set the access and modification time stamps of FD (a.k.a. FILE) to be
   TIMESPEC[0] and TIMESPEC[1], respectively.
   FD must be either negative -- in which case it is ignored --
   or a file descriptor that is open on FILE.
   If FD is nonnegative, then FILE can be NULL, which means
   use just futimes (or equivalent) instead of utimes (or equivalent),
   and fail if on an old system without futimes (or equivalent).
   If TIMESPEC is null, set the time stamps to the current time.
   Return 0 on success, -1 (setting errno) on failure.  */

int
futimens (int fd ATTRIBUTE_UNUSED,
	  char const *file, struct timespec const timespec[2])
{
  /* There's currently no interface to set file timestamps with
     nanosecond resolution, so do the best we can, discarding any
     fractional part of the timestamp.  */
#if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES
  struct timeval timeval[2];
  struct timeval const *t;
  if (timespec)
    {
      timeval[0].tv_sec = timespec[0].tv_sec;
      timeval[0].tv_usec = timespec[0].tv_nsec / 1000;
      timeval[1].tv_sec = timespec[1].tv_sec;
      timeval[1].tv_usec = timespec[1].tv_nsec / 1000;
      t = timeval;
    }
  else
    t = NULL;

# if HAVE_FUTIMESAT
  return fd < 0 ? futimesat (AT_FDCWD, file, t) : futimesat (fd, NULL, t);
# elif HAVE_FUTIMES
  if (0 <= fd)
    {
      if (futimes (fd, t) == 0)
	return 0;

      /* Don't worry about trying to speed things up by returning right
	 away here.  glibc futimes can incorrectly fail with errno ==
	 ENOENT if /proc isn't mounted.  Also, Mandrake 10.0 in high
	 security mode doesn't allow ordinary users to read /proc/self, so
	 glibc futimes incorrectly fails with errno == EACCES.  If futimes
	 fails with errno == EIO, EPERM, or EROFS, it's probably safe to
	 fail right away, but these cases are rare enough that they're not
	 worth optimizing, and who knows what other messed-up systems are
	 out there?  So play it safe and fall back on the code below.  */
    }
# endif
#endif

#if ! HAVE_FUTIMESAT

  if (!file)
    {
# if ! (HAVE_WORKING_UTIMES && HAVE_FUTIMES)
      errno = ENOSYS;
# endif

      /* Prefer EBADF to ENOSYS if both error numbers apply.  */
      if (errno == ENOSYS)
	{
	  int fd2 = dup (fd);
	  int dup_errno = errno;
	  if (0 <= fd2)
	    close (fd2);
	  errno = (fd2 < 0 && dup_errno == EBADF ? EBADF : ENOSYS);
	}

      return -1;
    }

# if HAVE_WORKING_UTIMES
  return utimes (file, t);
# else
  {
    struct utimbuf utimbuf;
    struct utimbuf const *ut;
    if (timespec)
      {
	utimbuf.actime = timespec[0].tv_sec;
	utimbuf.modtime = timespec[1].tv_sec;
	ut = &utimbuf;
      }
    else
      ut = NULL;

    return utime (file, ut);
  }
# endif

#endif
}

/* Set the access and modification time stamps of FILE to be
   TIMESPEC[0] and TIMESPEC[1], respectively.  */
int
utimens (char const *file, struct timespec const timespec[2])
{
  return futimens (-1, file, timespec);
}