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/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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 <stdint.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <memory>
#include <unwindstack/DexFiles.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Maps.h>
#include <unwindstack/Memory.h>
#include "DexFile.h"
namespace unwindstack {
struct DEXFileEntry32 {
uint32_t next;
uint32_t prev;
uint32_t dex_file;
};
struct DEXFileEntry64 {
uint64_t next;
uint64_t prev;
uint64_t dex_file;
};
DexFiles::DexFiles(std::shared_ptr<Memory>& memory) : memory_(memory) {}
DexFiles::DexFiles(std::shared_ptr<Memory>& memory, std::vector<std::string>& search_libs)
: memory_(memory), search_libs_(search_libs) {}
DexFiles::~DexFiles() {
for (auto& entry : files_) {
delete entry.second;
}
}
void DexFiles::SetArch(ArchEnum arch) {
switch (arch) {
case ARCH_ARM:
case ARCH_MIPS:
case ARCH_X86:
read_entry_ptr_func_ = &DexFiles::ReadEntryPtr32;
read_entry_func_ = &DexFiles::ReadEntry32;
break;
case ARCH_ARM64:
case ARCH_MIPS64:
case ARCH_X86_64:
read_entry_ptr_func_ = &DexFiles::ReadEntryPtr64;
read_entry_func_ = &DexFiles::ReadEntry64;
break;
case ARCH_UNKNOWN:
abort();
}
}
uint64_t DexFiles::ReadEntryPtr32(uint64_t addr) {
uint32_t entry;
const uint32_t field_offset = 12; // offset of first_entry_ in the descriptor struct.
if (!memory_->ReadFully(addr + field_offset, &entry, sizeof(entry))) {
return 0;
}
return entry;
}
uint64_t DexFiles::ReadEntryPtr64(uint64_t addr) {
uint64_t entry;
const uint32_t field_offset = 16; // offset of first_entry_ in the descriptor struct.
if (!memory_->ReadFully(addr + field_offset, &entry, sizeof(entry))) {
return 0;
}
return entry;
}
bool DexFiles::ReadEntry32() {
DEXFileEntry32 entry;
if (!memory_->ReadFully(entry_addr_, &entry, sizeof(entry)) || entry.dex_file == 0) {
entry_addr_ = 0;
return false;
}
addrs_.push_back(entry.dex_file);
entry_addr_ = entry.next;
return true;
}
bool DexFiles::ReadEntry64() {
DEXFileEntry64 entry;
if (!memory_->ReadFully(entry_addr_, &entry, sizeof(entry)) || entry.dex_file == 0) {
entry_addr_ = 0;
return false;
}
addrs_.push_back(entry.dex_file);
entry_addr_ = entry.next;
return true;
}
void DexFiles::Init(Maps* maps) {
if (initialized_) {
return;
}
initialized_ = true;
entry_addr_ = 0;
const std::string dex_debug_name("__dex_debug_descriptor");
for (MapInfo* info : *maps) {
if (!(info->flags & PROT_EXEC) || !(info->flags & PROT_READ) || info->offset != 0) {
continue;
}
if (!search_libs_.empty()) {
bool found = false;
const char* lib = basename(info->name.c_str());
for (const std::string& name : search_libs_) {
if (name == lib) {
found = true;
break;
}
}
if (!found) {
continue;
}
}
Elf* elf = info->GetElf(memory_, true);
uint64_t ptr;
// Find first non-empty list (libart might be loaded multiple times).
if (elf->GetGlobalVariable(dex_debug_name, &ptr) && ptr != 0) {
entry_addr_ = (this->*read_entry_ptr_func_)(ptr + info->start);
if (entry_addr_ != 0) {
break;
}
}
}
}
DexFile* DexFiles::GetDexFile(uint64_t dex_file_offset, MapInfo* info) {
// Lock while processing the data.
DexFile* dex_file;
auto entry = files_.find(dex_file_offset);
if (entry == files_.end()) {
dex_file = DexFile::Create(dex_file_offset, memory_.get(), info);
files_[dex_file_offset] = dex_file;
} else {
dex_file = entry->second;
}
return dex_file;
}
bool DexFiles::GetAddr(size_t index, uint64_t* addr) {
if (index < addrs_.size()) {
*addr = addrs_[index];
return true;
}
if (entry_addr_ != 0 && (this->*read_entry_func_)()) {
*addr = addrs_.back();
return true;
}
return false;
}
void DexFiles::GetMethodInformation(Maps* maps, MapInfo* info, uint64_t dex_pc,
std::string* method_name, uint64_t* method_offset) {
std::lock_guard<std::mutex> guard(lock_);
if (!initialized_) {
Init(maps);
}
size_t index = 0;
uint64_t addr;
while (GetAddr(index++, &addr)) {
if (addr < info->start || addr >= info->end) {
continue;
}
DexFile* dex_file = GetDexFile(addr, info);
if (dex_file != nullptr &&
dex_file->GetMethodInformation(dex_pc - addr, method_name, method_offset)) {
break;
}
}
}
} // namespace unwindstack