sysdeps/unix/sysv/linux/mmap64.c

   1 /* Copyright (C) 1999-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Jakub Jelinek <jakub@redhat.com>, 1999.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <sys/mman.h>
  22 #include <string.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26
  27 /* This is always 12, even on architectures where PAGE_SHIFT != 12.  */
  28 #ifndef MMAP2_PAGE_SHIFT
  29 # define MMAP2_PAGE_SHIFT 12
  30 #endif
  31 #if MMAP2_PAGE_SHIFT == -1
  32 static int page_shift;
  33 #else
  34 #define page_shift MMAP2_PAGE_SHIFT
  35 #endif
  36
  37
  38 void *
  39 __mmap64 (void *addr, size_t len, int prot, int flags, int fd, off64_t offset)
  40 {
  41 #if MMAP2_PAGE_SHIFT == -1
  42   if (page_shift == 0)
  43     {
  44       int page_size = __getpagesize ();
  45       page_shift = __ffs (page_size) - 1;
  46     }
  47 #endif
  48   if (offset & ((1 << page_shift) - 1))
  49     return (void *) INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
  50   void *result;
  51   result = (void *)
  52     INLINE_SYSCALL (mmap2, 6, addr,
  53                     len, prot, flags, fd,
  54                     (off_t) (offset >> page_shift));
  55   return result;
  56 }
  57 weak_alias (__mmap64, mmap64)