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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <sys/mman.h> // mprotect
#include <unistd.h> // sysconf
#include "mozilla/ipc/SharedMemory.h"
#if defined(XP_MACOSX) && defined(__x86_64__)
# include "prenv.h"
#endif
namespace mozilla {
namespace ipc {
#if defined(XP_MACOSX) && defined(__x86_64__)
std::atomic<size_t> sPageSizeOverride = 0;
#endif
void SharedMemory::SystemProtect(char* aAddr, size_t aSize, int aRights) {
if (!SystemProtectFallible(aAddr, aSize, aRights)) {
MOZ_CRASH("can't mprotect()");
}
}
bool SharedMemory::SystemProtectFallible(char* aAddr, size_t aSize,
int aRights) {
int flags = 0;
if (aRights & RightsRead) flags |= PROT_READ;
if (aRights & RightsWrite) flags |= PROT_WRITE;
if (RightsNone == aRights) flags = PROT_NONE;
return 0 == mprotect(aAddr, aSize, flags);
}
size_t SharedMemory::SystemPageSize() {
#if defined(XP_MACOSX) && defined(__x86_64__)
if (sPageSizeOverride == 0) {
if (PR_GetEnv("MOZ_SHMEM_PAGESIZE_16K")) {
sPageSizeOverride = 16 * 1024;
} else {
sPageSizeOverride = sysconf(_SC_PAGESIZE);
}
}
return sPageSizeOverride;
#else
return sysconf(_SC_PAGESIZE);
#endif
}
} // namespace ipc
} // namespace mozilla