libsyscall/wrappers/legacy/munmap.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 <sys/types.h>
  30 #include <sys/mman.h>
  31 #include <mach/vm_param.h>
  32 #include <mach/mach_init.h>
  33 #include "stack_logging_internal.h"
  34
  35 /*
  36  * Stub function to account for the differences in standard compliance
  37  * while maintaining binary backward compatibility.
  38  *
  39  * This is only the legacy behavior.
  40  */
  41 extern int __munmap(void *, size_t);
  42
  43 int
  44 munmap(void *addr, size_t len)
  45 {
  46         size_t  offset;
  47
  48         if (len == 0) {
  49                 /*
  50                  * Standard compliance now requires the system to return EINVAL
  51                  * for munmap(addr, 0).  Return success now to maintain
  52                  * backwards compatibility.
  53                  */
  54                 return 0;
  55         }
  56         /*
  57          * Page-align "addr" since the system now requires it
  58          * for standards compliance.
  59          * Update "len" to reflect the adjustment and still cover the same area.
  60          */
  61         offset = ((uintptr_t) addr) & PAGE_MASK;
  62         addr = (void *) (((uintptr_t) addr) & ~PAGE_MASK);
  63         len += offset;
  64
  65         int result = __munmap(addr, len);
  66
  67         if (__syscall_logger) {
  68                 __syscall_logger(stack_logging_type_vm_deallocate, (uintptr_t)mach_task_self(), (uintptr_t)addr, len, 0, 0);
  69         }
  70
  71         return result;
  72 }
  73 #endif /* NO_SYSCALL_LEGACY */