libsyscall/wrappers/legacy/mprotect.c

   1 /*
   2  * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #ifndef NO_SYSCALL_LEGACY
  25
  26 #define _NONSTD_SOURCE
  27 #include <sys/cdefs.h>
  28
  29 #include "_errno.h"
  30 #include <sys/types.h>
  31 #include <sys/mman.h>
  32 #include <mach/vm_param.h>
  33
  34 /*
  35  * Stub function to account for the differences in standard compliance
  36  * while maintaining binary backward compatibility.
  37  *
  38  * This is only the legacy behavior.
  39  */
  40 extern int __mprotect(void *, size_t, int);
  41
  42 int
  43 mprotect(void *addr, size_t len, int prot)
  44 {
  45         void    *aligned_addr;
  46         size_t  offset;
  47         int     rv;
  48
  49         /*
  50          * Page-align "addr" since the system now requires it
  51          * for standards compliance.
  52          * Update "len" to reflect the alignment.
  53          */
  54         offset = ((uintptr_t) addr) & PAGE_MASK;
  55         aligned_addr = (void *) (((uintptr_t) addr) & ~PAGE_MASK);
  56         len += offset;
  57         rv = __mprotect(aligned_addr, len, prot);
  58         if (rv == -1 && errno == ENOMEM) {
  59                 /*
  60                  * Standards now require that we return ENOMEM if there was
  61                  * a hole in the address range.  Panther and earlier used
  62                  * to return an EINVAL error, so honor backwards compatibility.
  63                  */
  64                 errno = EINVAL;
  65         }
  66         return rv;
  67 }
  68
  69 #endif /* NO_SYSCALL_LEGACY */