sysdeps/unix/sysv/linux/mmap64.c

   1 /* Copyright (C) 1999,2000,2001,2002,2006,2010 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <unistd.h>
  22 #include <sys/mman.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26 #include <bp-checks.h>
  27
  28 #include <kernel-features.h>
  29
  30 #ifdef __NR_mmap2
  31
  32 /* This is always 12, even on architectures where PAGE_SHIFT != 12.  */
  33 # if MMAP2_PAGE_SHIFT == -1
  34 static int page_shift;
  35 # else
  36 #  ifndef MMAP2_PAGE_SHIFT
  37 #   define MMAP2_PAGE_SHIFT 12
  38 #  endif
  39 # define page_shift MMAP2_PAGE_SHIFT
  40 # endif
  41
  42 # ifndef __ASSUME_MMAP2_SYSCALL
  43 static int have_no_mmap2;
  44 # endif
  45 #endif
  46
  47
  48 void *
  49 __mmap64 (void *addr, size_t len, int prot, int flags, int fd, off64_t offset)
  50 {
  51 #ifdef __NR_mmap2
  52 # if MMAP2_PAGE_SHIFT == -1
  53   if (page_shift == 0)
  54     {
  55       int page_size = getpagesize ();
  56       while ((1 << ++page_shift) != page_size)
  57         ;
  58     }
  59 # endif
  60   if (offset & ((1 << page_shift) - 1))
  61     {
  62       __set_errno (EINVAL);
  63       return MAP_FAILED;
  64     }
  65 # ifndef __ASSUME_MMAP2_SYSCALL
  66   if (! have_no_mmap2)
  67 # endif
  68     {
  69 # ifndef __ASSUME_MMAP2_SYSCALL
  70       int saved_errno = errno;
  71 # endif
  72       void *result;
  73       __ptrvalue (result) = (void *__unbounded)
  74         INLINE_SYSCALL (mmap2, 6, __ptrvalue (addr),
  75                         len, prot, flags, fd,
  76                         (off_t) (offset >> MMAP2_PAGE_SHIFT));
  77 # if __BOUNDED_POINTERS__
  78       __ptrlow (result) = __ptrvalue (result);
  79       __ptrhigh (result) = __ptrvalue (result) + len;
  80 # endif
  81 # ifndef __ASSUME_MMAP2_SYSCALL
  82       if (result != MAP_FAILED || errno != ENOSYS)
  83 # endif
  84         return result;
  85
  86 # ifndef __ASSUME_MMAP2_SYSCALL
  87       __set_errno (saved_errno);
  88       have_no_mmap2 = 1;
  89 # endif
  90     }
  91 #endif
  92 #ifndef __ASSUME_MMAP2_SYSCALL
  93   if (offset != (off_t) offset || (offset + len) != (off_t) (offset + len))
  94     {
  95       __set_errno (EINVAL);
  96       return MAP_FAILED;
  97     }
  98
  99   return __mmap (addr, len, prot, flags, fd, (off_t) offset);
 100 #endif
 101 }
 102 weak_alias (__mmap64, mmap64)