unplugged-system/system/unwinding/libunwindstack/tools/unwind_for_offline.cpp

421 lines
14 KiB
C++

/*
* Copyright (C) 2017 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 <cstdio>
#define _GNU_SOURCE 1
#include <inttypes.h>
#include <stdio.h>
#include <sys/mman.h>
#include <algorithm>
#include <cstdlib>
#include <filesystem>
#include <memory>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
#include <unwindstack/Elf.h>
#include <unwindstack/JitDebug.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Maps.h>
#include <unwindstack/Memory.h>
#include <unwindstack/Regs.h>
#include <unwindstack/Unwinder.h>
#include "utils/ProcessTracer.h"
#include <android-base/file.h>
#include <android-base/parseint.h>
#include <android-base/stringprintf.h>
namespace {
constexpr pid_t kMinPid = 1;
constexpr int kAllCmdOptionsParsed = -1;
int usage(int exit_code) {
fprintf(stderr, "USAGE: unwind_for_offline [-t] [-e FILE] [-f[FILE]] <PID>\n\n");
fprintf(stderr, "OPTIONS:\n");
fprintf(stderr, "-t\n");
fprintf(stderr, " Dump offline snapshot for all threads of <PID>.\n");
fprintf(stderr, "-e FILE\n");
fprintf(stderr, " If FILE is a valid ELF file included in /proc/<PID>/maps,\n");
fprintf(stderr, " unwind_for_offline will wait until the current frame (PC)\n");
fprintf(stderr, " lies within the .so file given by FILE. FILE should be\n");
fprintf(stderr, " base name of the path (the component following the final\n");
fprintf(stderr, " '/') rather than the fully qualified path.\n");
fprintf(stderr, "-f [FILE]\n");
fprintf(stderr, " Write info (e.g. frames and stack range) logs to a file\n");
fprintf(stderr, " rather than to the stdout/stderr. If FILE is not\n");
fprintf(stderr, " specified, the output file will be named 'output.txt'.\n");
return exit_code;
}
bool EnsureProcInDesiredElf(const std::string& elf_name, unwindstack::ProcessTracer& proc) {
if (proc.UsesSharedLibrary(proc.pid(), elf_name)) {
printf("Confirmed pid %d does use %s. Waiting for PC to lie within %s...\n", proc.pid(),
elf_name.c_str(), elf_name.c_str());
if (!proc.StopInDesiredElf(elf_name)) return false;
} else {
fprintf(stderr, "Process %d does not use library %s.\n", proc.pid(), elf_name.c_str());
return false;
}
return true;
}
bool CreateAndChangeDumpDir(std::filesystem::path thread_dir, pid_t tid, bool is_main_thread) {
std::string dir_name = std::to_string(tid);
if (is_main_thread) dir_name += "_main-thread";
thread_dir /= dir_name;
if (!std::filesystem::create_directory(thread_dir)) {
fprintf(stderr, "Failed to create directory for tid %d\n", tid);
return false;
}
std::filesystem::current_path(thread_dir);
return true;
}
bool SaveRegs(unwindstack::Regs* regs) {
std::unique_ptr<FILE, decltype(&fclose)> fp(fopen("regs.txt", "we+"), &fclose);
if (fp == nullptr) {
perror("Failed to create file regs.txt");
return false;
}
regs->IterateRegisters([&fp](const char* name, uint64_t value) {
fprintf(fp.get(), "%s: %" PRIx64 "\n", name, value);
});
return true;
}
bool SaveStack(pid_t tid, const std::vector<std::pair<uint64_t, uint64_t>>& stacks,
FILE* output_fp) {
for (size_t i = 0; i < stacks.size(); i++) {
std::string file_name;
if (stacks.size() != 1) {
file_name = "stack" + std::to_string(i) + ".data";
} else {
file_name = "stack.data";
}
// Do this first, so if it fails, we don't create the file.
uint64_t sp_start = stacks[i].first;
uint64_t sp_end = stacks[i].second;
std::vector<uint8_t> buffer(sp_end - sp_start);
auto process_memory = unwindstack::Memory::CreateProcessMemory(tid);
if (!process_memory->Read(sp_start, buffer.data(), buffer.size())) {
fprintf(stderr, "Unable to read stack data.\n");
return false;
}
fprintf(output_fp, "\nSaving the stack 0x%" PRIx64 "-0x%" PRIx64 "\n", sp_start, sp_end);
std::unique_ptr<FILE, decltype(&fclose)> fp(fopen(file_name.c_str(), "we+"), &fclose);
if (fp == nullptr) {
perror("Failed to create stack.data");
return false;
}
size_t bytes = fwrite(&sp_start, 1, sizeof(sp_start), fp.get());
if (bytes != sizeof(sp_start)) {
fprintf(stderr, "Failed to write sp_start data: sizeof(sp_start) %zu, written %zu\n",
sizeof(sp_start), bytes);
return false;
}
bytes = fwrite(buffer.data(), 1, buffer.size(), fp.get());
if (bytes != buffer.size()) {
fprintf(stderr, "Failed to write all stack data: stack size %zu, written %zu\n",
buffer.size(), bytes);
return false;
}
}
return true;
}
bool CopyElf(unwindstack::MapInfo* map_info, std::string* name) {
std::string cur_name = android::base::Basename(map_info->name());
std::unique_ptr<FILE, decltype(&fclose)> fp(fopen(map_info->name().c_str(), "re"), &fclose);
if (fp == nullptr) {
perror((std::string("Cannot open ") + map_info->name().c_str()).c_str());
return false;
}
std::unique_ptr<FILE, decltype(&fclose)> output(fopen(cur_name.c_str(), "we+"), &fclose);
if (output == nullptr) {
perror((std::string("Cannot create file " + cur_name)).c_str());
return false;
}
std::vector<uint8_t> buffer(10000);
size_t bytes;
while ((bytes = fread(buffer.data(), 1, buffer.size(), fp.get())) > 0) {
size_t bytes_written = fwrite(buffer.data(), 1, bytes, output.get());
if (bytes_written != bytes) {
fprintf(stderr, "Bytes written doesn't match bytes read: read %zu, written %zu\n", bytes,
bytes_written);
return false;
}
}
*name = std::move(cur_name);
return true;
}
bool CreateElfFromMemory(pid_t tid, unwindstack::MapInfo* map_info, std::string* name) {
std::string cur_name;
if (map_info->name().empty()) {
cur_name = android::base::StringPrintf("anonymous_%" PRIx64, map_info->start());
} else {
cur_name = android::base::StringPrintf(
"%s_%" PRIx64, android::base::Basename(map_info->name()).c_str(), map_info->start());
}
// If this is a mapped in file, it might not be possible to read the entire
// map, so read all that is readable.
std::vector<uint8_t> buffer(map_info->end() - map_info->start());
auto memory = unwindstack::Memory::CreateProcessMemory(tid);
size_t bytes = memory->Read(map_info->start(), buffer.data(), buffer.size());
if (bytes == 0) {
fprintf(stderr, "Cannot read data from address %" PRIx64 " length %zu\n", map_info->start(),
buffer.size());
return false;
}
std::unique_ptr<FILE, decltype(&fclose)> output(fopen(cur_name.c_str(), "we+"), &fclose);
if (output == nullptr) {
perror((std::string("Cannot create ") + cur_name).c_str());
return false;
}
size_t bytes_written = fwrite(buffer.data(), 1, bytes, output.get());
if (bytes_written != bytes) {
fprintf(stderr, "Failed to write all data to file: bytes read %zu, written %zu\n", bytes,
bytes_written);
return false;
}
*name = std::move(cur_name);
return true;
}
bool CopyMapInfo(pid_t tid, unwindstack::MapInfo* map_info,
std::unordered_map<std::string, std::string>& copied_files, std::string* name) {
auto entry = copied_files.find(map_info->name());
if (entry != copied_files.end()) {
// Already copied the file, do nothing.
*name = entry->second;
return true;
}
if (CopyElf(map_info, name)) {
copied_files[map_info->name()] = *name;
return true;
}
if (CreateElfFromMemory(tid, map_info, name)) {
return true;
}
fprintf(stderr, "Cannot save memory or file for map ");
if (!map_info->name().empty()) {
fprintf(stderr, "%s\n", map_info->name().c_str());
} else {
fprintf(stderr, "anonymous:%" PRIx64 "\n", map_info->start());
}
return false;
}
void WriteMapEntry(FILE* fp, unwindstack::MapInfo* map_info, const std::string& name) {
char perms[5] = {"---p"};
if (map_info->flags() & PROT_READ) {
perms[0] = 'r';
}
if (map_info->flags() & PROT_WRITE) {
perms[1] = 'w';
}
if (map_info->flags() & PROT_EXEC) {
perms[2] = 'x';
}
fprintf(fp, "%" PRIx64 "-%" PRIx64 " %s %" PRIx64 " 00:00 0", map_info->start(), map_info->end(),
perms, map_info->offset());
if (!name.empty()) {
fprintf(fp, " %s", name.c_str());
}
fprintf(fp, "\n");
}
void SaveMapInfo(FILE* maps_fp, pid_t tid, unwindstack::MapInfo* map_info,
std::unordered_map<std::string, std::string>& copied_files) {
auto prev_info = map_info->GetPrevRealMap();
if (prev_info != nullptr) {
SaveMapInfo(maps_fp, tid, prev_info.get(), copied_files);
}
std::string map_name;
if (CopyMapInfo(tid, map_info, copied_files, &map_name)) {
WriteMapEntry(maps_fp, map_info, map_name);
}
}
bool SaveData(pid_t tid, const std::filesystem::path& cwd, bool is_main_thread, FILE* output_fp) {
fprintf(output_fp, "-------------------- tid = %d %s--------------------\n", tid,
is_main_thread ? "(main thread) " : "--------------");
unwindstack::Regs* regs = unwindstack::Regs::RemoteGet(tid);
if (regs == nullptr) {
fprintf(stderr, "Unable to get remote reg data.\n");
return false;
}
if (!CreateAndChangeDumpDir(cwd, tid, is_main_thread)) {
return false;
}
// Save the current state of the registers.
if (!SaveRegs(regs)) {
return false;
}
// Do an unwind so we know how much of the stack to save, and what
// elf files are involved.
unwindstack::UnwinderFromPid unwinder(1024, tid);
unwinder.SetRegs(regs);
uint64_t sp = regs->sp();
unwinder.Unwind();
std::vector<std::pair<uint64_t, uint64_t>> stacks;
unwindstack::Maps* maps = unwinder.GetMaps();
uint64_t sp_map_start = 0;
auto map_info = maps->Find(sp);
if (map_info != nullptr) {
stacks.emplace_back(std::make_pair(sp, map_info->end()));
sp_map_start = map_info->start();
}
std::unordered_map<uintptr_t, unwindstack::MapInfo*> map_infos;
for (const auto& frame : unwinder.frames()) {
auto map_info = maps->Find(frame.sp);
if (map_info != nullptr && sp_map_start != map_info->start()) {
stacks.emplace_back(std::make_pair(frame.sp, map_info->end()));
sp_map_start = map_info->start();
}
map_infos[reinterpret_cast<uintptr_t>(frame.map_info.get())] = frame.map_info.get();
}
for (size_t i = 0; i < unwinder.NumFrames(); i++) {
fprintf(output_fp, "%s\n", unwinder.FormatFrame(i).c_str());
}
if (!SaveStack(tid, stacks, output_fp)) {
return false;
}
std::unique_ptr<FILE, decltype(&fclose)> maps_fp(fopen("maps.txt", "we+"), &fclose);
if (maps_fp == nullptr) {
perror("Failed to create maps.txt");
return false;
}
std::vector<unwindstack::MapInfo*> sorted_map_infos(map_infos.size());
std::transform(map_infos.begin(), map_infos.end(), sorted_map_infos.begin(),
[](auto entry) { return entry.second; });
std::sort(sorted_map_infos.begin(), sorted_map_infos.end(),
[](auto a, auto b) { return b->start() > a->start(); });
std::unordered_map<std::string, std::string> copied_files;
for (auto& map_info : sorted_map_infos) {
SaveMapInfo(maps_fp.get(), tid, map_info, copied_files);
}
fprintf(output_fp, "------------------------------------------------------------------\n");
return true;
}
} // namespace
int main(int argc, char** argv) {
if (argc < 2) return usage(EXIT_FAILURE);
bool dump_threads = false;
std::string elf_name;
std::unique_ptr<FILE, decltype(&fclose)> output_fp(nullptr, &fclose);
int opt;
while ((opt = getopt(argc, argv, ":te:f::")) != kAllCmdOptionsParsed) {
switch (opt) {
case 't': {
dump_threads = true;
break;
}
case 'e': {
elf_name = optarg;
if (elf_name == "-f") {
fprintf(stderr, "Missing argument for option e.\n");
return usage(EXIT_FAILURE);
}
break;
}
case 'f': {
const std::string& output_filename = optarg != nullptr ? optarg : "output.txt";
if (optind == argc - 2) {
fprintf(stderr, "Ensure there is no space between '-f' and the filename provided.\n");
return usage(EXIT_FAILURE);
}
output_fp.reset(fopen(output_filename.c_str(), "ae"));
break;
}
case '?': {
if (isprint(optopt))
fprintf(stderr, "Unknown option `-%c'.\n", optopt);
else
fprintf(stderr, "Unknown option character `\\x%x'.\n", optopt);
return usage(EXIT_FAILURE);
}
case ':': {
fprintf(stderr, "Missing arg for option %c.\n", optopt);
return usage(EXIT_FAILURE);
}
default: {
return usage(EXIT_FAILURE);
}
}
}
if (optind != argc - 1) return usage(EXIT_FAILURE);
pid_t pid;
if (!android::base::ParseInt(argv[optind], &pid, kMinPid, std::numeric_limits<pid_t>::max()))
return usage(EXIT_FAILURE);
unwindstack::ProcessTracer proc(pid, dump_threads);
if (!proc.Stop()) return EXIT_FAILURE;
if (!elf_name.empty()) {
if (!EnsureProcInDesiredElf(elf_name, proc)) return EXIT_FAILURE;
}
if (!output_fp) output_fp.reset(stdout);
std::filesystem::path cwd = std::filesystem::current_path();
if (!proc.Attach(proc.pid())) return EXIT_FAILURE;
if (!SaveData(proc.pid(), cwd, /*is_main_thread=*/proc.IsTracingThreads(), output_fp.get()))
return EXIT_FAILURE;
if (!proc.Detach(proc.pid())) return EXIT_FAILURE;
for (const pid_t& tid : proc.tids()) {
if (!proc.Attach(tid)) return EXIT_FAILURE;
if (!SaveData(tid, cwd, /*is_main_thread=*/false, output_fp.get())) return EXIT_FAILURE;
if (!proc.Detach(tid)) return EXIT_FAILURE;
}
printf("\nSuccess!\n");
return EXIT_SUCCESS;
}