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/*
* Copyright (C) 2015 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 "dso.h"
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <limits>
#include <memory>
#include <optional>
#include <string_view>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/strings.h>
#include "JITDebugReader.h"
#include "environment.h"
#include "kallsyms.h"
#include "read_apk.h"
#include "read_dex_file.h"
#include "read_elf.h"
#include "utils.h"
namespace simpleperf {
using android::base::EndsWith;
using android::base::StartsWith;
namespace simpleperf_dso_impl {
std::string RemovePathSeparatorSuffix(const std::string& path) {
// Don't remove path separator suffix for '/'.
if (EndsWith(path, OS_PATH_SEPARATOR) && path.size() > 1u) {
return path.substr(0, path.size() - 1);
}
return path;
}
void DebugElfFileFinder::Reset() {
vdso_64bit_.clear();
vdso_32bit_.clear();
symfs_dir_.clear();
build_id_to_file_map_.clear();
}
bool DebugElfFileFinder::SetSymFsDir(const std::string& symfs_dir) {
symfs_dir_ = RemovePathSeparatorSuffix(symfs_dir);
if (!IsDir(symfs_dir_)) {
LOG(ERROR) << "Invalid symfs_dir '" << symfs_dir_ << "'";
return false;
}
std::string build_id_list_file = symfs_dir_ + OS_PATH_SEPARATOR + "build_id_list";
std::string build_id_list;
if (android::base::ReadFileToString(build_id_list_file, &build_id_list)) {
for (auto& line : android::base::Split(build_id_list, "\n")) {
std::vector<std::string> items = android::base::Split(line, "=");
if (items.size() == 2u) {
build_id_to_file_map_[items[0]] = symfs_dir_ + OS_PATH_SEPARATOR + items[1];
}
}
}
return true;
}
bool DebugElfFileFinder::AddSymbolDir(const std::string& symbol_dir) {
if (!IsDir(symbol_dir)) {
LOG(ERROR) << "Invalid symbol dir " << symbol_dir;
return false;
}
std::string dir = RemovePathSeparatorSuffix(symbol_dir);
CollectBuildIdInDir(dir);
return true;
}
void DebugElfFileFinder::CollectBuildIdInDir(const std::string& dir) {
for (const std::string& entry : GetEntriesInDir(dir)) {
std::string path = dir + OS_PATH_SEPARATOR + entry;
if (IsDir(path)) {
CollectBuildIdInDir(path);
} else {
BuildId build_id;
ElfStatus status;
auto elf = ElfFile::Open(path, &status);
if (status == ElfStatus::NO_ERROR && elf->GetBuildId(&build_id) == ElfStatus::NO_ERROR) {
build_id_to_file_map_[build_id.ToString()] = path;
}
}
}
}
void DebugElfFileFinder::SetVdsoFile(const std::string& vdso_file, bool is_64bit) {
if (is_64bit) {
vdso_64bit_ = vdso_file;
} else {
vdso_32bit_ = vdso_file;
}
}
static bool CheckDebugFilePath(const std::string& path, BuildId& build_id,
bool report_build_id_mismatch) {
ElfStatus status;
auto elf = ElfFile::Open(path, &status);
if (!elf) {
return false;
}
BuildId debug_build_id;
status = elf->GetBuildId(&debug_build_id);
if (status != ElfStatus::NO_ERROR && status != ElfStatus::NO_BUILD_ID) {
return false;
}
// Native libraries in apks and kernel modules may not have build ids.
// So build_id and debug_build_id can either be empty, or have the same value.
bool match = build_id == debug_build_id;
if (!match && report_build_id_mismatch) {
LOG(WARNING) << path << " isn't used because of build id mismatch: expected " << build_id
<< ", real " << debug_build_id;
}
return match;
}
std::string DebugElfFileFinder::FindDebugFile(const std::string& dso_path, bool force_64bit,
BuildId& build_id) {
if (dso_path == "[vdso]") {
if (force_64bit && !vdso_64bit_.empty()) {
return vdso_64bit_;
} else if (!force_64bit && !vdso_32bit_.empty()) {
return vdso_32bit_;
}
}
if (build_id.IsEmpty()) {
// Try reading build id from file if we don't already have one.
GetBuildIdFromDsoPath(dso_path, &build_id);
}
// 1. Try build_id_to_file_map.
if (!build_id_to_file_map_.empty()) {
if (!build_id.IsEmpty() || GetBuildIdFromDsoPath(dso_path, &build_id)) {
auto it = build_id_to_file_map_.find(build_id.ToString());
if (it != build_id_to_file_map_.end() && CheckDebugFilePath(it->second, build_id, false)) {
return it->second;
}
}
}
if (!symfs_dir_.empty()) {
// 2. Try concatenating symfs_dir and dso_path.
std::string path = GetPathInSymFsDir(dso_path);
if (CheckDebugFilePath(path, build_id, true)) {
return path;
}
// 3. Try concatenating symfs_dir and basename of dso_path.
path = symfs_dir_ + OS_PATH_SEPARATOR + android::base::Basename(dso_path);
if (CheckDebugFilePath(path, build_id, false)) {
return path;
}
}
// 4. Try concatenating /usr/lib/debug and dso_path.
// Linux host can store debug shared libraries in /usr/lib/debug.
if (CheckDebugFilePath("/usr/lib/debug" + dso_path, build_id, false)) {
return "/usr/lib/debug" + dso_path;
}
return dso_path;
}
std::string DebugElfFileFinder::GetPathInSymFsDir(const std::string& path) {
auto add_symfs_prefix = [&](const std::string& path) {
if (StartsWith(path, OS_PATH_SEPARATOR)) {
return symfs_dir_ + path;
}
return symfs_dir_ + OS_PATH_SEPARATOR + path;
};
if (OS_PATH_SEPARATOR == '/') {
return add_symfs_prefix(path);
}
// Paths in recorded perf.data uses '/' as path separator. When reporting on Windows, it needs
// to be converted to '\\'.
auto tuple = SplitUrlInApk(path);
if (std::get<0>(tuple)) {
std::string apk_path = std::get<1>(tuple);
std::string entry_path = std::get<2>(tuple);
std::replace(apk_path.begin(), apk_path.end(), '/', OS_PATH_SEPARATOR);
return GetUrlInApk(add_symfs_prefix(apk_path), entry_path);
}
std::string elf_path = path;
std::replace(elf_path.begin(), elf_path.end(), '/', OS_PATH_SEPARATOR);
return add_symfs_prefix(elf_path);
}
} // namespace simpleperf_dso_impl
static OneTimeFreeAllocator symbol_name_allocator;
Symbol::Symbol(std::string_view name, uint64_t addr, uint64_t len)
: addr(addr),
len(len),
name_(symbol_name_allocator.AllocateString(name)),
demangled_name_(nullptr),
dump_id_(UINT_MAX) {}
const char* Symbol::DemangledName() const {
if (demangled_name_ == nullptr) {
const std::string s = Dso::Demangle(name_);
SetDemangledName(s);
}
return demangled_name_;
}
void Symbol::SetDemangledName(std::string_view name) const {
if (name == name_) {
demangled_name_ = name_;
} else {
demangled_name_ = symbol_name_allocator.AllocateString(name);
}
}
static bool CompareSymbolToAddr(const Symbol& s, uint64_t addr) {
return s.addr < addr;
}
static bool CompareAddrToSymbol(uint64_t addr, const Symbol& s) {
return addr < s.addr;
}
bool Dso::demangle_ = true;
std::string Dso::vmlinux_;
std::string Dso::kallsyms_;
std::unordered_map<std::string, BuildId> Dso::build_id_map_;
size_t Dso::dso_count_;
uint32_t Dso::g_dump_id_;
simpleperf_dso_impl::DebugElfFileFinder Dso::debug_elf_file_finder_;
void Dso::SetDemangle(bool demangle) {
demangle_ = demangle;
}
extern "C" char* __cxa_demangle(const char* mangled_name, char* buf, size_t* n, int* status);
std::string Dso::Demangle(const std::string& name) {
if (!demangle_) {
return name;
}
int status;
bool is_linker_symbol = (name.find(linker_prefix) == 0);
const char* mangled_str = name.c_str();
if (is_linker_symbol) {
mangled_str += linker_prefix.size();
}
std::string result = name;
char* demangled_name = __cxa_demangle(mangled_str, nullptr, nullptr, &status);
if (status == 0) {
if (is_linker_symbol) {
result = std::string("[linker]") + demangled_name;
} else {
result = demangled_name;
}
free(demangled_name);
} else if (is_linker_symbol) {
result = std::string("[linker]") + mangled_str;
}
return result;
}
bool Dso::SetSymFsDir(const std::string& symfs_dir) {
return debug_elf_file_finder_.SetSymFsDir(symfs_dir);
}
bool Dso::AddSymbolDir(const std::string& symbol_dir) {
return debug_elf_file_finder_.AddSymbolDir(symbol_dir);
}
void Dso::SetVmlinux(const std::string& vmlinux) {
vmlinux_ = vmlinux;
}
void Dso::SetBuildIds(const std::vector<std::pair<std::string, BuildId>>& build_ids) {
std::unordered_map<std::string, BuildId> map;
for (auto& pair : build_ids) {
LOG(DEBUG) << "build_id_map: " << pair.first << ", " << pair.second.ToString();
map.insert(pair);
}
build_id_map_ = std::move(map);
}
void Dso::SetVdsoFile(const std::string& vdso_file, bool is_64bit) {
debug_elf_file_finder_.SetVdsoFile(vdso_file, is_64bit);
}
BuildId Dso::FindExpectedBuildIdForPath(const std::string& path) {
auto it = build_id_map_.find(path);
if (it != build_id_map_.end()) {
return it->second;
}
return BuildId();
}
BuildId Dso::GetExpectedBuildId() {
return FindExpectedBuildIdForPath(path_);
}
Dso::Dso(DsoType type, const std::string& path, const std::string& debug_file_path)
: type_(type),
path_(path),
debug_file_path_(debug_file_path),
is_loaded_(false),
dump_id_(UINT_MAX),
symbol_dump_id_(0),
symbol_warning_loglevel_(android::base::WARNING) {
size_t pos = path.find_last_of("/\\");
if (pos != std::string::npos) {
file_name_ = path.substr(pos + 1);
} else {
file_name_ = path;
}
dso_count_++;
}
Dso::~Dso() {
if (--dso_count_ == 0) {
// Clean up global variables when no longer used.
symbol_name_allocator.Clear();
demangle_ = true;
vmlinux_.clear();
kallsyms_.clear();
build_id_map_.clear();
g_dump_id_ = 0;
debug_elf_file_finder_.Reset();
}
}
uint32_t Dso::CreateDumpId() {
CHECK(!HasDumpId());
return dump_id_ = g_dump_id_++;
}
uint32_t Dso::CreateSymbolDumpId(const Symbol* symbol) {
CHECK(!symbol->HasDumpId());
symbol->dump_id_ = symbol_dump_id_++;
return symbol->dump_id_;
}
std::optional<uint64_t> Dso::IpToFileOffset(uint64_t ip, uint64_t map_start, uint64_t map_pgoff) {
return ip - map_start + map_pgoff;
}
const Symbol* Dso::FindSymbol(uint64_t vaddr_in_dso) {
if (!is_loaded_) {
LoadSymbols();
}
auto it = std::upper_bound(symbols_.begin(), symbols_.end(), vaddr_in_dso, CompareAddrToSymbol);
if (it != symbols_.begin()) {
--it;
if (it->addr <= vaddr_in_dso && (it->addr + it->len > vaddr_in_dso)) {
return &*it;
}
}
if (!unknown_symbols_.empty()) {
auto it = unknown_symbols_.find(vaddr_in_dso);
if (it != unknown_symbols_.end()) {
return &it->second;
}
}
return nullptr;
}
void Dso::SetSymbols(std::vector<Symbol>* symbols) {
symbols_ = std::move(*symbols);
symbols->clear();
}
void Dso::AddUnknownSymbol(uint64_t vaddr_in_dso, const std::string& name) {
unknown_symbols_.insert(std::make_pair(vaddr_in_dso, Symbol(name, vaddr_in_dso, 1)));
}
bool Dso::IsForJavaMethod() const {
if (type_ == DSO_DEX_FILE) {
return true;
}
if (type_ == DSO_ELF_FILE) {
if (JITDebugReader::IsPathInJITSymFile(path_)) {
return true;
}
// JITDebugReader in old versions generates symfiles in 'TemporaryFile-XXXXXX'.
size_t pos = path_.rfind('/');
pos = (pos == std::string::npos) ? 0 : pos + 1;
return StartsWith(std::string_view(&path_[pos], path_.size() - pos), "TemporaryFile");
}
return false;
}
void Dso::LoadSymbols() {
if (!is_loaded_) {
is_loaded_ = true;
std::vector<Symbol> symbols = LoadSymbolsImpl();
if (symbols_.empty()) {
symbols_ = std::move(symbols);
} else {
std::vector<Symbol> merged_symbols;
std::set_union(symbols_.begin(), symbols_.end(), symbols.begin(), symbols.end(),
std::back_inserter(merged_symbols), Symbol::CompareValueByAddr);
symbols_ = std::move(merged_symbols);
}
}
}
static void ReportReadElfSymbolResult(
ElfStatus result, const std::string& path, const std::string& debug_file_path,
android::base::LogSeverity warning_loglevel = android::base::WARNING) {
if (result == ElfStatus::NO_ERROR) {
LOG(VERBOSE) << "Read symbols from " << debug_file_path << " successfully";
} else if (result == ElfStatus::NO_SYMBOL_TABLE) {
if (path == "[vdso]") {
// Vdso only contains dynamic symbol table, and we can't change that.
return;
}
// Lacking symbol table isn't considered as an error but worth reporting.
LOG(warning_loglevel) << debug_file_path << " doesn't contain symbol table";
} else {
LOG(warning_loglevel) << "failed to read symbols from " << debug_file_path << ": " << result;
}
}
static void SortAndFixSymbols(std::vector<Symbol>& symbols) {
std::sort(symbols.begin(), symbols.end(), Symbol::CompareValueByAddr);
Symbol* prev_symbol = nullptr;
for (auto& symbol : symbols) {
if (prev_symbol != nullptr && prev_symbol->len == 0) {
prev_symbol->len = symbol.addr - prev_symbol->addr;
}
prev_symbol = &symbol;
}
}
class DexFileDso : public Dso {
public:
DexFileDso(const std::string& path, const std::string& debug_file_path)
: Dso(DSO_DEX_FILE, path, debug_file_path) {}
void AddDexFileOffset(uint64_t dex_file_offset) override {
auto it = std::lower_bound(dex_file_offsets_.begin(), dex_file_offsets_.end(), dex_file_offset);
if (it != dex_file_offsets_.end() && *it == dex_file_offset) {
return;
}
dex_file_offsets_.insert(it, dex_file_offset);
}
const std::vector<uint64_t>* DexFileOffsets() override { return &dex_file_offsets_; }
uint64_t IpToVaddrInFile(uint64_t ip, uint64_t map_start, uint64_t map_pgoff) override {
return ip - map_start + map_pgoff;
}
std::vector<Symbol> LoadSymbolsImpl() override {
std::vector<Symbol> symbols;
auto tuple = SplitUrlInApk(debug_file_path_);
bool status = false;
auto symbol_callback = [&](DexFileSymbol* symbol) {
symbols.emplace_back(symbol->name, symbol->addr, symbol->size);
};
if (std::get<0>(tuple)) {
std::unique_ptr<ArchiveHelper> ahelper = ArchiveHelper::CreateInstance(std::get<1>(tuple));
ZipEntry entry;
std::vector<uint8_t> data;
if (ahelper && ahelper->FindEntry(std::get<2>(tuple), &entry) &&
ahelper->GetEntryData(entry, &data)) {
status = ReadSymbolsFromDexFileInMemory(data.data(), data.size(), dex_file_offsets_,
symbol_callback);
}
} else {
status = ReadSymbolsFromDexFile(debug_file_path_, dex_file_offsets_, symbol_callback);
}
if (!status) {
android::base::LogSeverity level =
symbols_.empty() ? android::base::WARNING : android::base::DEBUG;
LOG(level) << "Failed to read symbols from " << debug_file_path_;
return symbols;
}
LOG(VERBOSE) << "Read symbols from " << debug_file_path_ << " successfully";
SortAndFixSymbols(symbols);
return symbols;
}
private:
std::vector<uint64_t> dex_file_offsets_;
};
class ElfDso : public Dso {
public:
ElfDso(const std::string& path, const std::string& debug_file_path)
: Dso(DSO_ELF_FILE, path, debug_file_path) {}
std::string_view GetReportPath() const override {
if (JITDebugReader::IsPathInJITSymFile(path_)) {
if (path_.find(kJITAppCacheFile) != path_.npos) {
return "[JIT app cache]";
}
return "[JIT zygote cache]";
}
return path_;
}
void SetMinExecutableVaddr(uint64_t min_vaddr, uint64_t file_offset) override {
min_vaddr_ = min_vaddr;
file_offset_of_min_vaddr_ = file_offset;
}
void GetMinExecutableVaddr(uint64_t* min_vaddr, uint64_t* file_offset) override {
if (type_ == DSO_DEX_FILE) {
return dex_file_dso_->GetMinExecutableVaddr(min_vaddr, file_offset);
}
if (min_vaddr_ == uninitialized_value) {
min_vaddr_ = 0;
BuildId build_id = GetExpectedBuildId();
ElfStatus status;
auto elf = ElfFile::Open(debug_file_path_, &build_id, &status);
if (elf) {
min_vaddr_ = elf->ReadMinExecutableVaddr(&file_offset_of_min_vaddr_);
} else {
LOG(WARNING) << "failed to read min virtual address of " << debug_file_path_ << ": "
<< status;
}
}
*min_vaddr = min_vaddr_;
*file_offset = file_offset_of_min_vaddr_;
}
uint64_t IpToVaddrInFile(uint64_t ip, uint64_t map_start, uint64_t map_pgoff) override {
if (type_ == DSO_DEX_FILE) {
return dex_file_dso_->IpToVaddrInFile(ip, map_start, map_pgoff);
}
uint64_t min_vaddr;
uint64_t file_offset_of_min_vaddr;
GetMinExecutableVaddr(&min_vaddr, &file_offset_of_min_vaddr);
if (file_offset_of_min_vaddr == uninitialized_value) {
return ip - map_start + min_vaddr;
}
// Apps may make part of the executable segment of a shared library writeable, which can
// generate multiple executable segments at runtime. So use map_pgoff to calculate
// vaddr_in_file.
return ip - map_start + map_pgoff - file_offset_of_min_vaddr + min_vaddr;
}
void AddDexFileOffset(uint64_t dex_file_offset) override {
if (type_ == DSO_ELF_FILE) {
// When simpleperf does unwinding while recording, it processes mmap records before reading
// dex file linked list (via JITDebugReader). To process mmap records, it creates Dso
// objects of type ELF_FILE. Then after reading dex file linked list, it realizes some
// ELF_FILE Dso objects should actually be DEX_FILE, because they have dex file offsets.
// So here converts ELF_FILE Dso into DEX_FILE Dso.
type_ = DSO_DEX_FILE;
dex_file_dso_.reset(new DexFileDso(path_, path_));
}
dex_file_dso_->AddDexFileOffset(dex_file_offset);
}
const std::vector<uint64_t>* DexFileOffsets() override {
return dex_file_dso_ ? dex_file_dso_->DexFileOffsets() : nullptr;
}
protected:
std::vector<Symbol> LoadSymbolsImpl() override {
if (dex_file_dso_) {
return dex_file_dso_->LoadSymbolsImpl();
}
std::vector<Symbol> symbols;
BuildId build_id = GetExpectedBuildId();
auto symbol_callback = [&](const ElfFileSymbol& symbol) {
if (symbol.is_func || (symbol.is_label && symbol.is_in_text_section)) {
symbols.emplace_back(symbol.name, symbol.vaddr, symbol.len);
}
};
ElfStatus status;
auto elf = ElfFile::Open(debug_file_path_, &build_id, &status);
if (elf) {
status = elf->ParseSymbols(symbol_callback);
}
ReportReadElfSymbolResult(status, path_, debug_file_path_,
symbols_.empty() ? android::base::WARNING : android::base::DEBUG);
SortAndFixSymbols(symbols);
return symbols;
}
private:
static constexpr uint64_t uninitialized_value = std::numeric_limits<uint64_t>::max();
uint64_t min_vaddr_ = uninitialized_value;
uint64_t file_offset_of_min_vaddr_ = uninitialized_value;
std::unique_ptr<DexFileDso> dex_file_dso_;
};
class KernelDso : public Dso {
public:
KernelDso(const std::string& path, const std::string& debug_file_path)
: Dso(DSO_KERNEL, path, debug_file_path) {
if (!vmlinux_.empty()) {
// Use vmlinux as the kernel debug file.
BuildId build_id = GetExpectedBuildId();
ElfStatus status;
if (ElfFile::Open(vmlinux_, &build_id, &status)) {
debug_file_path_ = vmlinux_;
has_debug_file_ = true;
}
} else if (IsRegularFile(debug_file_path_)) {
has_debug_file_ = true;
}
}
// IpToVaddrInFile() and LoadSymbols() must be consistent in fixing addresses changed by kernel
// address space layout randomization.
uint64_t IpToVaddrInFile(uint64_t ip, uint64_t map_start, uint64_t) override {
if (map_start != 0 && GetKernelStartAddr() != 0) {
// Fix kernel addresses changed by kernel address randomization.
fix_kernel_address_randomization_ = true;
return ip - map_start + GetKernelStartAddr();
}
return ip;
}
std::optional<uint64_t> IpToFileOffset(uint64_t ip, uint64_t map_start, uint64_t) override {
if (map_start != 0 && GetKernelStartOffset() != 0) {
return ip - map_start + GetKernelStartOffset();
}
return std::nullopt;
}
protected:
std::vector<Symbol> LoadSymbolsImpl() override {
std::vector<Symbol> symbols;
if (has_debug_file_) {
ReadSymbolsFromDebugFile(&symbols);
}
if (symbols.empty() && !kallsyms_.empty()) {
ReadSymbolsFromKallsyms(kallsyms_, &symbols);
}
#if defined(__linux__)
if (symbols.empty()) {
ReadSymbolsFromProc(&symbols);
}
#endif // defined(__linux__)
SortAndFixSymbols(symbols);
if (!symbols.empty()) {
symbols.back().len = std::numeric_limits<uint64_t>::max() - symbols.back().addr;
}
return symbols;
}
private:
void ReadSymbolsFromDebugFile(std::vector<Symbol>* symbols) {
if (!fix_kernel_address_randomization_) {
LOG(WARNING) << "Don't know how to fix addresses changed by kernel address randomization. So "
"symbols in "
<< debug_file_path_ << " are not used";
return;
}
// symbols_ are kernel symbols got from /proc/kallsyms while recording. Those symbols are
// not fixed for kernel address randomization. So clear them to avoid mixing them with
// symbols in debug_file_path.
symbols_.clear();
auto symbol_callback = [&](const ElfFileSymbol& symbol) {
if (symbol.is_func) {
symbols->emplace_back(symbol.name, symbol.vaddr, symbol.len);
}
};
ElfStatus status;
if (auto elf = ElfFile::Open(debug_file_path_, &status); elf) {
status = elf->ParseSymbols(symbol_callback);
}
ReportReadElfSymbolResult(status, path_, debug_file_path_);
}
void ReadSymbolsFromKallsyms(std::string& kallsyms, std::vector<Symbol>* symbols) {
auto symbol_callback = [&](const KernelSymbol& symbol) {
if (strchr("TtWw", symbol.type) && symbol.addr != 0u) {
if (symbol.module == nullptr) {
symbols->emplace_back(symbol.name, symbol.addr, 0);
} else {
std::string name = std::string(symbol.name) + " [" + symbol.module + "]";
symbols->emplace_back(name, symbol.addr, 0);
}
}
return false;
};
ProcessKernelSymbols(kallsyms, symbol_callback);
if (symbols->empty()) {
LOG(WARNING) << "Symbol addresses in /proc/kallsyms on device are all zero. "
"`echo 0 >/proc/sys/kernel/kptr_restrict` if possible.";
}
}
#if defined(__linux__)
void ReadSymbolsFromProc(std::vector<Symbol>* symbols) {
BuildId build_id = GetExpectedBuildId();
if (!build_id.IsEmpty()) {
// Try /proc/kallsyms only when asked to do so, or when build id matches.
// Otherwise, it is likely to use /proc/kallsyms on host for perf.data recorded on device.
bool can_read_kallsyms = true;
if (!build_id.IsEmpty()) {
BuildId real_build_id;
if (!GetKernelBuildId(&real_build_id) || build_id != real_build_id) {
LOG(DEBUG) << "failed to read symbols from /proc/kallsyms: Build id mismatch";
can_read_kallsyms = false;
}
}
if (can_read_kallsyms) {
std::string kallsyms;
if (LoadKernelSymbols(&kallsyms)) {
ReadSymbolsFromKallsyms(kallsyms, symbols);
}
}
}
}
#endif // defined(__linux__)
uint64_t GetKernelStartAddr() {
if (!kernel_start_addr_) {
ParseKernelStartAddr();
}
return kernel_start_addr_.value();
}
uint64_t GetKernelStartOffset() {
if (!kernel_start_file_offset_) {
ParseKernelStartAddr();
}
return kernel_start_file_offset_.value();
}
void ParseKernelStartAddr() {
kernel_start_addr_ = 0;
kernel_start_file_offset_ = 0;
if (has_debug_file_) {
ElfStatus status;
if (auto elf = ElfFile::Open(debug_file_path_, &status); elf) {
for (const auto& section : elf->GetSectionHeader()) {
if (section.name == ".text") {
kernel_start_addr_ = section.vaddr;
kernel_start_file_offset_ = section.file_offset;
break;
}
}
}
}
}
bool has_debug_file_ = false;
bool fix_kernel_address_randomization_ = false;
std::optional<uint64_t> kernel_start_addr_;
std::optional<uint64_t> kernel_start_file_offset_;
};
class KernelModuleDso : public Dso {
public:
KernelModuleDso(const std::string& path, const std::string& debug_file_path,
uint64_t memory_start, uint64_t memory_end, Dso* kernel_dso)
: Dso(DSO_KERNEL_MODULE, path, debug_file_path),
memory_start_(memory_start),
memory_end_(memory_end),
kernel_dso_(kernel_dso) {}
void SetMinExecutableVaddr(uint64_t min_vaddr, uint64_t memory_offset) override {
min_vaddr_ = min_vaddr;
memory_offset_of_min_vaddr_ = memory_offset;
}
void GetMinExecutableVaddr(uint64_t* min_vaddr, uint64_t* memory_offset) override {
if (!min_vaddr_) {
CalculateMinVaddr();
}
*min_vaddr = min_vaddr_.value();
*memory_offset = memory_offset_of_min_vaddr_.value();
}
uint64_t IpToVaddrInFile(uint64_t ip, uint64_t map_start, uint64_t) override {
uint64_t min_vaddr;
uint64_t memory_offset;
GetMinExecutableVaddr(&min_vaddr, &memory_offset);
return ip - map_start - memory_offset + min_vaddr;
}
protected:
std::vector<Symbol> LoadSymbolsImpl() override {
std::vector<Symbol> symbols;
BuildId build_id = GetExpectedBuildId();
auto symbol_callback = [&](const ElfFileSymbol& symbol) {
// We only know how to map ip addrs to symbols in text section.
if (symbol.is_in_text_section && (symbol.is_label || symbol.is_func)) {
symbols.emplace_back(symbol.name, symbol.vaddr, symbol.len);
}
};
ElfStatus status;
auto elf = ElfFile::Open(debug_file_path_, &build_id, &status);
if (elf) {
status = elf->ParseSymbols(symbol_callback);
}
ReportReadElfSymbolResult(status, path_, debug_file_path_,
symbols_.empty() ? android::base::WARNING : android::base::DEBUG);
SortAndFixSymbols(symbols);
return symbols;
}
private:
void CalculateMinVaddr() {
min_vaddr_ = 0;
memory_offset_of_min_vaddr_ = 0;
// min_vaddr and memory_offset are used to convert an ip addr of a kernel module to its
// vaddr_in_file, as shown in IpToVaddrInFile(). When the kernel loads a kernel module, it
// puts ALLOC sections (like .plt, .text.ftrace_trampoline, .text) in memory in order. The
// text section may not be at the start of the module memory. To do address conversion, we
// need to know its relative position in the module memory. There are two ways:
// 1. Read the kernel module file to calculate the relative position of .text section. It
// is relatively complex and depends on both PLT entries and the kernel version.
// 2. Find a module symbol in .text section, get its address in memory from /proc/kallsyms, and
// its vaddr_in_file from the kernel module file. Then other symbols in .text section can be
// mapped in the same way.
// Below we use the second method.
// 1. Select a module symbol in /proc/kallsyms.
kernel_dso_->LoadSymbols();
const auto& kernel_symbols = kernel_dso_->GetSymbols();
auto it = std::lower_bound(kernel_symbols.begin(), kernel_symbols.end(), memory_start_,
CompareSymbolToAddr);
const Symbol* kernel_symbol = nullptr;
while (it != kernel_symbols.end() && it->addr < memory_end_) {
if (strlen(it->Name()) > 0 && it->Name()[0] != '$') {
kernel_symbol = &*it;
break;
}
++it;
}
if (kernel_symbol == nullptr) {
return;
}
// 2. Find the symbol in .ko file.
std::string symbol_name = kernel_symbol->Name();
if (auto pos = symbol_name.rfind(' '); pos != std::string::npos) {
symbol_name.resize(pos);
}
LoadSymbols();
for (const auto& symbol : symbols_) {
if (symbol_name == symbol.Name()) {
min_vaddr_ = symbol.addr;
memory_offset_of_min_vaddr_ = kernel_symbol->addr - memory_start_;
return;
}
}
}
uint64_t memory_start_;
uint64_t memory_end_;
Dso* kernel_dso_;
std::optional<uint64_t> min_vaddr_;
std::optional<uint64_t> memory_offset_of_min_vaddr_;
};
class SymbolMapFileDso : public Dso {
public:
SymbolMapFileDso(const std::string& path) : Dso(DSO_SYMBOL_MAP_FILE, path, path) {}
uint64_t IpToVaddrInFile(uint64_t ip, uint64_t, uint64_t) override { return ip; }
protected:
std::vector<Symbol> LoadSymbolsImpl() override { return {}; }
};
class UnknownDso : public Dso {
public:
UnknownDso(const std::string& path) : Dso(DSO_UNKNOWN_FILE, path, path) {}
uint64_t IpToVaddrInFile(uint64_t ip, uint64_t, uint64_t) override { return ip; }
protected:
std::vector<Symbol> LoadSymbolsImpl() override { return std::vector<Symbol>(); }
};
std::unique_ptr<Dso> Dso::CreateDso(DsoType dso_type, const std::string& dso_path,
bool force_64bit) {
BuildId build_id = FindExpectedBuildIdForPath(dso_path);
std::string debug_path = debug_elf_file_finder_.FindDebugFile(dso_path, force_64bit, build_id);
switch (dso_type) {
case DSO_ELF_FILE:
return std::unique_ptr<Dso>(new ElfDso(dso_path, debug_path));
case DSO_KERNEL:
return std::unique_ptr<Dso>(new KernelDso(dso_path, debug_path));
case DSO_DEX_FILE:
return std::unique_ptr<Dso>(new DexFileDso(dso_path, dso_path));
case DSO_SYMBOL_MAP_FILE:
return std::unique_ptr<Dso>(new SymbolMapFileDso(dso_path));
case DSO_UNKNOWN_FILE:
return std::unique_ptr<Dso>(new UnknownDso(dso_path));
default:
LOG(FATAL) << "Unexpected dso_type " << static_cast<int>(dso_type);
}
return nullptr;
}
std::unique_ptr<Dso> Dso::CreateDsoWithBuildId(DsoType dso_type, const std::string& dso_path,
BuildId& build_id) {
std::string debug_path = debug_elf_file_finder_.FindDebugFile(dso_path, false, build_id);
switch (dso_type) {
case DSO_ELF_FILE:
return std::unique_ptr<Dso>(new ElfDso(dso_path, debug_path));
case DSO_KERNEL:
return std::unique_ptr<Dso>(new KernelDso(dso_path, debug_path));
case DSO_KERNEL_MODULE:
return std::unique_ptr<Dso>(new KernelModuleDso(dso_path, debug_path, 0, 0, nullptr));
default:
LOG(FATAL) << "Unexpected dso_type " << static_cast<int>(dso_type);
}
return nullptr;
}
std::unique_ptr<Dso> Dso::CreateKernelModuleDso(const std::string& dso_path, uint64_t memory_start,
uint64_t memory_end, Dso* kernel_dso) {
BuildId build_id = FindExpectedBuildIdForPath(dso_path);
std::string debug_path = debug_elf_file_finder_.FindDebugFile(dso_path, false, build_id);
return std::unique_ptr<Dso>(
new KernelModuleDso(dso_path, debug_path, memory_start, memory_end, kernel_dso));
}
const char* DsoTypeToString(DsoType dso_type) {
switch (dso_type) {
case DSO_KERNEL:
return "dso_kernel";
case DSO_KERNEL_MODULE:
return "dso_kernel_module";
case DSO_ELF_FILE:
return "dso_elf_file";
case DSO_DEX_FILE:
return "dso_dex_file";
case DSO_SYMBOL_MAP_FILE:
return "dso_symbol_map_file";
default:
return "unknown";
}
}
bool GetBuildIdFromDsoPath(const std::string& dso_path, BuildId* build_id) {
ElfStatus status;
auto elf = ElfFile::Open(dso_path, &status);
if (status == ElfStatus::NO_ERROR && elf->GetBuildId(build_id) == ElfStatus::NO_ERROR) {
return true;
}
return false;
}
} // namespace simpleperf