ipc/glue/SharedMemory_posix.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include <sys/mman.h>  // mprotect
   8 #include <unistd.h>    // sysconf
   9
  10 #include "mozilla/ipc/SharedMemory.h"
  11
  12 namespace mozilla {
  13 namespace ipc {
  14
  15 void SharedMemory::SystemProtect(char* aAddr, size_t aSize, int aRights) {
  16   if (!SystemProtectFallible(aAddr, aSize, aRights)) {
  17     MOZ_CRASH("can't mprotect()");
  18   }
  19 }
  20
  21 bool SharedMemory::SystemProtectFallible(char* aAddr, size_t aSize,
  22                                          int aRights) {
  23   int flags = 0;
  24   if (aRights & RightsRead) flags |= PROT_READ;
  25   if (aRights & RightsWrite) flags |= PROT_WRITE;
  26   if (RightsNone == aRights) flags = PROT_NONE;
  27
  28   return 0 == mprotect(aAddr, aSize, flags);
  29 }
  30
  31 size_t SharedMemory::SystemPageSize() { return sysconf(_SC_PAGESIZE); }
  32
  33 }  // namespace ipc
  34 }  // namespace mozilla