// Copyright 2014 The Crashpad Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "util/process/process_memory_mac.h"
#include <mach/mach_vm.h>
#include <string.h>
#include <algorithm>
#include "base/apple/mach_logging.h"
#include "base/check_op.h"
#include "base/logging.h"
#include "base/strings/stringprintf.h"
#include "util/stdlib/strnlen.h"
namespace crashpad {
ProcessMemoryMac::MappedMemory::~MappedMemory() {}
bool ProcessMemoryMac::MappedMemory::ReadCString(size_t offset,
std::string* string) const {
if (offset >= user_size_) {
LOG(WARNING) << "offset out of range";
return false;
}
const char* string_base = reinterpret_cast<const char*>(data_) + offset;
size_t max_length = user_size_ - offset;
size_t string_length = strnlen(string_base, max_length);
if (string_length == max_length) {
LOG(WARNING) << "unterminated string";
return false;
}
string->assign(string_base, string_length);
return true;
}
ProcessMemoryMac::MappedMemory::MappedMemory(vm_address_t vm_address,
size_t vm_size,
size_t user_offset,
size_t user_size)
: vm_(vm_address, vm_size),
data_(reinterpret_cast<const void*>(vm_address + user_offset)),
user_size_(user_size) {
vm_address_t vm_end = vm_address + vm_size;
vm_address_t user_address = reinterpret_cast<vm_address_t>(data_);
vm_address_t user_end = user_address + user_size;
DCHECK_GE(user_address, vm_address);
DCHECK_LE(user_address, vm_end);
DCHECK_GE(user_end, vm_address);
DCHECK_LE(user_end, vm_end);
}
ProcessMemoryMac::ProcessMemoryMac() : task_(TASK_NULL), initialized_() {}
bool ProcessMemoryMac::Initialize(task_t task) {
INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
task_ = task;
INITIALIZATION_STATE_SET_VALID(initialized_);
return true;
}
std::unique_ptr<ProcessMemoryMac::MappedMemory> ProcessMemoryMac::ReadMapped(
mach_vm_address_t address,
size_t size) const {
INITIALIZATION_STATE_DCHECK_VALID(initialized_);
if (size == 0) {
return std::unique_ptr<MappedMemory>(new MappedMemory(0, 0, 0, 0));
}
mach_vm_address_t region_address = mach_vm_trunc_page(address);
mach_vm_size_t region_size =
mach_vm_round_page(address - region_address + size);
vm_offset_t region;
mach_msg_type_number_t region_count;
kern_return_t kr =
mach_vm_read(task_, region_address, region_size, ®ion, ®ion_count);
if (kr != KERN_SUCCESS) {
MACH_LOG(WARNING, kr) << base::StringPrintf(
"mach_vm_read(0x%llx, 0x%llx)", region_address, region_size);
return std::unique_ptr<MappedMemory>();
}
if (region_count != region_size) {
LOG(ERROR) << base::StringPrintf(
"mach_vm_read() unexpected read: 0x%x != 0x%llx bytes",
region_count,
region_size);
if (region_count)
vm_deallocate(mach_task_self(), region, region_count);
return std::unique_ptr<MappedMemory>();
}
return std::unique_ptr<MappedMemory>(
new MappedMemory(region, region_size, address - region_address, size));
}
ssize_t ProcessMemoryMac::ReadUpTo(VMAddress address,
size_t size,
void* buffer) const {
INITIALIZATION_STATE_DCHECK_VALID(initialized_);
DCHECK_LE(size, (size_t)std::numeric_limits<ssize_t>::max());
std::unique_ptr<MappedMemory> memory = ReadMapped(address, size);
if (!memory) {
// If we can not read the entire mapping, try to perform a short read of the
// first page instead. This is necessary to support ReadCString().
size_t short_read = PAGE_SIZE - (address % PAGE_SIZE);
if (short_read >= size)
return -1;
memory = ReadMapped(address, short_read);
if (!memory)
return -1;
size = short_read;
}
memcpy(buffer, memory->data(), size);
return static_cast<ssize_t>(size);
}
} // namespace crashpad