glibc/sysdeps/unix/sysv/linux/mmap64.c

/* Copyright (C) 1999-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Jakub Jelinek <jakub@redhat.com>, 1999.

   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 <errno.h>
#include <unistd.h>
#include <sys/mman.h>
#include <string.h>

#include <sysdep.h>
#include <sys/syscall.h>

/* This is always 12, even on architectures where PAGE_SHIFT != 12.  */
#ifndef MMAP2_PAGE_SHIFT
# define MMAP2_PAGE_SHIFT 12
#endif
#if MMAP2_PAGE_SHIFT == -1
static int page_shift;
#else
#define page_shift MMAP2_PAGE_SHIFT
#endif


void *
__mmap64 (void *addr, size_t len, int prot, int flags, int fd, off64_t offset)
{
#if MMAP2_PAGE_SHIFT == -1
  if (page_shift == 0)
    {
      int page_size = __getpagesize ();
      page_shift = __ffs (page_size) - 1;
    }
#endif
  if (offset & ((1 << page_shift) - 1))
    return (void *) INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
  void *result;
  result = (void *)
    INLINE_SYSCALL (mmap2, 6, addr,
		    len, prot, flags, fd,
		    (off_t) (offset >> page_shift));
  return result;
}
weak_alias (__mmap64, mmap64)