/* Linux lseek implementation, 32 bits off_t.

   Copyright (C) 2016-2018 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 Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library.  If not, see

   <http://www.gnu.org/licenses/>.  */

#include <unistd.h>

#include <stdint.h>

#include <sys/types.h>

#include <sysdep.h>

#include <errno.h>

#ifndef __OFF_T_MATCHES_OFF64_T

/* Test for overflows of structures where we ask the kernel to fill them

   in with standard 64-bit syscalls but return them through APIs that

   only expose the low 32 bits of some fields.  */

static inline off_t lseek_overflow (loff_t res)

{

  off_t retval = (off_t) res;

  if (retval == res)

    return retval;

  __set_errno (EOVERFLOW);

  return (off_t) -1;

}

off_t

__lseek (int fd, off_t offset, int whence)

{

# ifdef __NR__llseek

  loff_t res;

  int rc = INLINE_SYSCALL_CALL (_llseek, fd,

				(long) (((uint64_t) (offset)) >> 32),

				(long) offset, &res, whence);

  return rc ?: lseek_overflow (res);

# else

  return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);

# endif

}

libc_hidden_def (__lseek)

weak_alias (__lseek, lseek)

strong_alias (__lseek, __libc_lseek)

#endif /* __OFF_T_MATCHES_OFF64_T  */