glibc/sysdeps/unix/sysv/linux/i386/fcntl.c

/* Copyright (C) 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

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

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

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

#include <sysdep.h>
#include <sys/syscall.h>
#include "../kernel-features.h"


#if __ASSUME_FCNTL64 == 0
/* This variable is shared with all files that check for fcntl64.  */
static int __have_no_fcntl64;
#endif

int
__libc_fcntl (int fd, int cmd, ...)
{
  va_list ap;
  void *arg;

  va_start (ap, cmd);
  arg = va_arg (ap, void *);
  va_end (ap);

#if __ASSUME_FCNTL64 > 0
  return INLINE_SYSCALL (fcntl64, 3, fd, cmd, arg);
#else
# ifdef __NR_fcntl64
  if (! __have_no_fcntl64)
    {
      int result = INLINE_SYSCALL (fcntl64, 3, fd, cmd, arg);
      if (result >= 0 || errno != ENOSYS)
	return result;

      __have_no_fcntl64 = 1;
    }
# endif
  switch (cmd)
    {
    case F_GETLK64:
      /* Convert arg from flock64 to flock and back.  */
      {
	struct flock fl;
	struct flock64 *fl64 = arg;
	int res;

	fl.l_start = (off_t)fl64->l_start;
	/* Check if we can represent the values with the smaller type.  */
	if ((off64_t) fl.l_start != fl64->l_start)
	  {
	    __set_errno (EOVERFLOW);
	    return -1;
	  }
	fl.l_len = (off_t) fl64->l_len;
	/* Check if we can represent the values with the smaller type.  */
	if ((off64_t) fl.l_len != fl64->l_len)
	  {
	    __set_errno (EOVERFLOW);
	    return -1;
	  }
	fl.l_type = fl64->l_type;
	fl.l_whence = fl64->l_whence;
	fl.l_pid = fl64->l_pid;

	res = INLINE_SYSCALL (fcntl, 3, fd, cmd, &fl);
	if (res  != 0)
	  return res;
	/* Everything ok, convert back.  */
	fl64->l_type = fl.l_type;
	fl64->l_whence = fl.l_whence;
	fl64->l_start = fl.l_start;
	fl64->l_len = fl.l_len;
	fl64->l_pid = fl.l_pid;

	return 0;
      }
    case F_SETLK64:
    case F_SETLKW64:
      /* Try to convert arg from flock64 to flock.  */
      {
	struct flock fl;
	struct flock64 *fl64 = arg;

	fl.l_start = (off_t) fl64->l_start;
	/* Check if we can represent the values with the smaller type.  */
	if ((off64_t) fl.l_start != fl64->l_start)
	  {
	    __set_errno (EOVERFLOW);
	    return -1;
	  }
	fl.l_len = (off_t)fl64->l_len;
	/* Check if we can represent the values with the smaller type.  */
	if ((off64_t) fl.l_len != fl64->l_len)
	  {
	    __set_errno (EOVERFLOW);
	    return -1;
	  }
	fl.l_type = fl64->l_type;
	fl.l_whence = fl64->l_whence;
	fl.l_pid = fl64->l_pid;
	return INLINE_SYSCALL (fcntl, 3, fd, cmd, &fl);
      }
    default:
      return INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
    }
  return -1;
#endif  /* __ASSUME_FCNTL64  */
}

weak_alias (__libc_fcntl, __fcntl)
weak_alias (__libc_fcntl, fcntl)