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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/memory/protected_memory.h"
#include <stdint.h>
#include <sys/mman.h>
#include <unistd.h>
#if defined(OS_LINUX)
#include <sys/resource.h>
#endif // defined(OS_LINUX)
#if defined(OS_MACOSX) && !defined(OS_IOS)
#include <mach/mach.h>
#include <mach/mach_vm.h>
#endif // defined(OS_MACOSX) && !defined(OS_IOS)
#include "base/posix/eintr_wrapper.h"
#include "base/process/process_metrics.h"
#include "base/synchronization/lock.h"
#include "build/build_config.h"
namespace base {
namespace {
bool SetMemory(void* start, void* end, int prot) {
DCHECK(end > start);
const uintptr_t page_mask = ~(base::GetPageSize() - 1);
const uintptr_t page_start = reinterpret_cast<uintptr_t>(start) & page_mask;
return mprotect(reinterpret_cast<void*>(page_start),
reinterpret_cast<uintptr_t>(end) - page_start, prot) == 0;
}
} // namespace
bool AutoWritableMemory::SetMemoryReadWrite(void* start, void* end) {
return SetMemory(start, end, PROT_READ | PROT_WRITE);
}
bool AutoWritableMemory::SetMemoryReadOnly(void* start, void* end) {
return SetMemory(start, end, PROT_READ);
}
#if defined(OS_LINUX)
void AssertMemoryIsReadOnly(const void* ptr) {
#if DCHECK_IS_ON()
const uintptr_t page_mask = ~(base::GetPageSize() - 1);
const uintptr_t page_start = reinterpret_cast<uintptr_t>(ptr) & page_mask;
// Note: We've casted away const here, which should not be meaningful since
// if the memory is written to we will abort immediately.
int result =
getrlimit(RLIMIT_NPROC, reinterpret_cast<struct rlimit*>(page_start));
DCHECK_EQ(result, -1);
DCHECK_EQ(errno, EFAULT);
#endif // DCHECK_IS_ON()
}
#elif defined(OS_MACOSX) && !defined(OS_IOS)
void AssertMemoryIsReadOnly(const void* ptr) {
#if DCHECK_IS_ON()
mach_port_t object_name;
vm_region_basic_info_64 region_info;
mach_vm_size_t size = 1;
mach_msg_type_number_t count = VM_REGION_BASIC_INFO_COUNT_64;
kern_return_t kr = mach_vm_region(
mach_task_self(), reinterpret_cast<mach_vm_address_t*>(&ptr), &size,
VM_REGION_BASIC_INFO_64, reinterpret_cast<vm_region_info_t>(®ion_info),
&count, &object_name);
DCHECK_EQ(kr, KERN_SUCCESS);
DCHECK_EQ(region_info.protection, VM_PROT_READ);
#endif // DCHECK_IS_ON()
}
#endif // defined(OS_LINUX) || (defined(OS_MACOSX) && !defined(OS_IOS))
} // namespace base
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