/*
* 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 "environment.h"
#include <inttypes.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/utsname.h>
#include <limits>
#include <set>
#include <unordered_map>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/strings.h>
#include <android-base/stringprintf.h>
#include <procinfo/process.h>
#if defined(__ANDROID__)
#include <android-base/properties.h>
#endif
#include "event_type.h"
#include "IOEventLoop.h"
#include "read_elf.h"
#include "thread_tree.h"
#include "utils.h"
#include "workload.h"
class LineReader {
public:
explicit LineReader(FILE* fp) : fp_(fp), buf_(nullptr), bufsize_(0) {
}
~LineReader() {
free(buf_);
fclose(fp_);
}
char* ReadLine() {
if (getline(&buf_, &bufsize_, fp_) != -1) {
return buf_;
}
return nullptr;
}
size_t MaxLineSize() {
return bufsize_;
}
private:
FILE* fp_;
char* buf_;
size_t bufsize_;
};
std::vector<int> GetOnlineCpus() {
std::vector<int> result;
FILE* fp = fopen("/sys/devices/system/cpu/online", "re");
if (fp == nullptr) {
PLOG(ERROR) << "can't open online cpu information";
return result;
}
LineReader reader(fp);
char* line;
if ((line = reader.ReadLine()) != nullptr) {
result = GetCpusFromString(line);
}
CHECK(!result.empty()) << "can't get online cpu information";
return result;
}
std::vector<int> GetCpusFromString(const std::string& s) {
std::set<int> cpu_set;
bool have_dash = false;
const char* p = s.c_str();
char* endp;
int last_cpu;
int cpu;
// Parse line like: 0,1-3, 5, 7-8
while ((cpu = static_cast<int>(strtol(p, &endp, 10))) != 0 || endp != p) {
if (have_dash && !cpu_set.empty()) {
for (int t = last_cpu + 1; t < cpu; ++t) {
cpu_set.insert(t);
}
}
have_dash = false;
cpu_set.insert(cpu);
last_cpu = cpu;
p = endp;
while (!isdigit(*p) && *p != '\0') {
if (*p == '-') {
have_dash = true;
}
++p;
}
}
return std::vector<int>(cpu_set.begin(), cpu_set.end());
}
static std::vector<KernelMmap> GetLoadedModules() {
std::vector<KernelMmap> result;
FILE* fp = fopen("/proc/modules", "re");
if (fp == nullptr) {
// There is no /proc/modules on Android devices, so we don't print error if failed to open it.
PLOG(DEBUG) << "failed to open file /proc/modules";
return result;
}
LineReader reader(fp);
char* line;
while ((line = reader.ReadLine()) != nullptr) {
// Parse line like: nf_defrag_ipv6 34768 1 nf_conntrack_ipv6, Live 0xffffffffa0fe5000
char name[reader.MaxLineSize()];
uint64_t addr;
uint64_t len;
if (sscanf(line, "%s%" PRIu64 "%*u%*s%*s 0x%" PRIx64, name, &len, &addr) == 3) {
KernelMmap map;
map.name = name;
map.start_addr = addr;
map.len = len;
result.push_back(map);
}
}
bool all_zero = true;
for (const auto& map : result) {
if (map.start_addr != 0) {
all_zero = false;
}
}
if (all_zero) {
LOG(DEBUG) << "addresses in /proc/modules are all zero, so ignore kernel modules";
return std::vector<KernelMmap>();
}
return result;
}
static void GetAllModuleFiles(const std::string& path,
std::unordered_map<std::string, std::string>* module_file_map) {
for (const auto& name : GetEntriesInDir(path)) {
std::string entry_path = path + "/" + name;
if (IsRegularFile(entry_path) && android::base::EndsWith(name, ".ko")) {
std::string module_name = name.substr(0, name.size() - 3);
std::replace(module_name.begin(), module_name.end(), '-', '_');
module_file_map->insert(std::make_pair(module_name, entry_path));
} else if (IsDir(entry_path)) {
GetAllModuleFiles(entry_path, module_file_map);
}
}
}
static std::vector<KernelMmap> GetModulesInUse() {
std::vector<KernelMmap> module_mmaps = GetLoadedModules();
if (module_mmaps.empty()) {
return std::vector<KernelMmap>();
}
std::unordered_map<std::string, std::string> module_file_map;
#if defined(__ANDROID__)
// Search directories listed in "File locations" section in
// https://source.android.com/devices/architecture/kernel/modular-kernels.
for (const auto& path : {"/vendor/lib/modules", "/odm/lib/modules", "/lib/modules"}) {
GetAllModuleFiles(path, &module_file_map);
}
#else
utsname uname_buf;
if (TEMP_FAILURE_RETRY(uname(&uname_buf)) != 0) {
PLOG(ERROR) << "uname() failed";
return std::vector<KernelMmap>();
}
std::string linux_version = uname_buf.release;
std::string module_dirpath = "/lib/modules/" + linux_version + "/kernel";
GetAllModuleFiles(module_dirpath, &module_file_map);
#endif
for (auto& module : module_mmaps) {
auto it = module_file_map.find(module.name);
if (it != module_file_map.end()) {
module.filepath = it->second;
}
}
return module_mmaps;
}
void GetKernelAndModuleMmaps(KernelMmap* kernel_mmap, std::vector<KernelMmap>* module_mmaps) {
kernel_mmap->name = DEFAULT_KERNEL_MMAP_NAME;
kernel_mmap->start_addr = 0;
kernel_mmap->len = std::numeric_limits<uint64_t>::max();
kernel_mmap->filepath = kernel_mmap->name;
*module_mmaps = GetModulesInUse();
for (auto& map : *module_mmaps) {
if (map.filepath.empty()) {
map.filepath = "[" + map.name + "]";
}
}
}
static bool ReadThreadNameAndPid(pid_t tid, std::string* comm, pid_t* pid) {
android::procinfo::ProcessInfo procinfo;
if (!android::procinfo::GetProcessInfo(tid, &procinfo)) {
return false;
}
if (comm != nullptr) {
*comm = procinfo.name;
}
if (pid != nullptr) {
*pid = procinfo.pid;
}
return true;
}
std::vector<pid_t> GetThreadsInProcess(pid_t pid) {
std::vector<pid_t> result;
android::procinfo::GetProcessTids(pid, &result);
return result;
}
bool IsThreadAlive(pid_t tid) {
return IsDir(android::base::StringPrintf("/proc/%d", tid));
}
bool GetProcessForThread(pid_t tid, pid_t* pid) {
return ReadThreadNameAndPid(tid, nullptr, pid);
}
bool GetThreadName(pid_t tid, std::string* name) {
return ReadThreadNameAndPid(tid, name, nullptr);
}
std::vector<pid_t> GetAllProcesses() {
std::vector<pid_t> result;
std::vector<std::string> entries = GetEntriesInDir("/proc");
for (const auto& entry : entries) {
pid_t pid;
if (!android::base::ParseInt(entry.c_str(), &pid, 0)) {
continue;
}
result.push_back(pid);
}
return result;
}
bool GetThreadMmapsInProcess(pid_t pid, std::vector<ThreadMmap>* thread_mmaps) {
std::string map_file = android::base::StringPrintf("/proc/%d/maps", pid);
FILE* fp = fopen(map_file.c_str(), "re");
if (fp == nullptr) {
PLOG(DEBUG) << "can't open file " << map_file;
return false;
}
thread_mmaps->clear();
LineReader reader(fp);
char* line;
while ((line = reader.ReadLine()) != nullptr) {
// Parse line like: 00400000-00409000 r-xp 00000000 fc:00 426998 /usr/lib/gvfs/gvfsd-http
uint64_t start_addr, end_addr, pgoff;
char type[reader.MaxLineSize()];
char execname[reader.MaxLineSize()];
strcpy(execname, "");
if (sscanf(line, "%" PRIx64 "-%" PRIx64 " %s %" PRIx64 " %*x:%*x %*u %s\n", &start_addr,
&end_addr, type, &pgoff, execname) < 4) {
continue;
}
if (strcmp(execname, "") == 0) {
strcpy(execname, DEFAULT_EXECNAME_FOR_THREAD_MMAP);
}
ThreadMmap thread;
thread.start_addr = start_addr;
thread.len = end_addr - start_addr;
thread.pgoff = pgoff;
thread.name = execname;
thread.executable = (type[2] == 'x');
thread_mmaps->push_back(thread);
}
return true;
}
bool GetKernelBuildId(BuildId* build_id) {
ElfStatus result = GetBuildIdFromNoteFile("/sys/kernel/notes", build_id);
if (result != ElfStatus::NO_ERROR) {
LOG(DEBUG) << "failed to read /sys/kernel/notes: " << result;
}
return result == ElfStatus::NO_ERROR;
}
bool GetModuleBuildId(const std::string& module_name, BuildId* build_id) {
std::string notefile = "/sys/module/" + module_name + "/notes/.note.gnu.build-id";
return GetBuildIdFromNoteFile(notefile, build_id);
}
bool GetValidThreadsFromThreadString(const std::string& tid_str, std::set<pid_t>* tid_set) {
std::vector<std::string> strs = android::base::Split(tid_str, ",");
for (const auto& s : strs) {
int tid;
if (!android::base::ParseInt(s.c_str(), &tid, 0)) {
LOG(ERROR) << "Invalid tid '" << s << "'";
return false;
}
if (!IsDir(android::base::StringPrintf("/proc/%d", tid))) {
LOG(ERROR) << "Non existing thread '" << tid << "'";
return false;
}
tid_set->insert(tid);
}
return true;
}
/*
* perf event paranoia level:
* -1 - not paranoid at all
* 0 - disallow raw tracepoint access for unpriv
* 1 - disallow cpu events for unpriv
* 2 - disallow kernel profiling for unpriv
* 3 - disallow user profiling for unpriv
*/
static bool ReadPerfEventParanoid(int* value) {
std::string s;
if (!android::base::ReadFileToString("/proc/sys/kernel/perf_event_paranoid", &s)) {
PLOG(DEBUG) << "failed to read /proc/sys/kernel/perf_event_paranoid";
return false;
}
s = android::base::Trim(s);
if (!android::base::ParseInt(s.c_str(), value)) {
PLOG(ERROR) << "failed to parse /proc/sys/kernel/perf_event_paranoid: " << s;
return false;
}
return true;
}
bool CanRecordRawData() {
int value;
return IsRoot() || (ReadPerfEventParanoid(&value) && value == -1);
}
static const char* GetLimitLevelDescription(int limit_level) {
switch (limit_level) {
case -1: return "unlimited";
case 0: return "disallowing raw tracepoint access for unpriv";
case 1: return "disallowing cpu events for unpriv";
case 2: return "disallowing kernel profiling for unpriv";
case 3: return "disallowing user profiling for unpriv";
default: return "unknown level";
}
}
bool CheckPerfEventLimit() {
// Root is not limited by /proc/sys/kernel/perf_event_paranoid. However, the monitored threads
// may create child processes not running as root. To make sure the child processes have
// enough permission to create inherited tracepoint events, write -1 to perf_event_paranoid.
// See http://b/62230699.
if (IsRoot() && android::base::WriteStringToFile("-1", "/proc/sys/kernel/perf_event_paranoid")) {
return true;
}
int limit_level;
bool can_read_paranoid = ReadPerfEventParanoid(&limit_level);
if (can_read_paranoid && limit_level <= 1) {
return true;
}
#if defined(__ANDROID__)
const std::string prop_name = "security.perf_harden";
std::string prop_value = android::base::GetProperty(prop_name, "");
if (prop_value.empty()) {
// can't do anything if there is no such property.
return true;
}
if (prop_value == "0") {
return true;
}
// Try to enable perf_event_paranoid by setprop security.perf_harden=0.
if (android::base::SetProperty(prop_name, "0")) {
sleep(1);
if (can_read_paranoid && ReadPerfEventParanoid(&limit_level) && limit_level <= 1) {
return true;
}
if (android::base::GetProperty(prop_name, "") == "0") {
return true;
}
}
if (can_read_paranoid) {
LOG(WARNING) << "/proc/sys/kernel/perf_event_paranoid is " << limit_level
<< ", " << GetLimitLevelDescription(limit_level) << ".";
}
LOG(WARNING) << "Try using `adb shell setprop security.perf_harden 0` to allow profiling.";
return false;
#else
if (can_read_paranoid) {
LOG(WARNING) << "/proc/sys/kernel/perf_event_paranoid is " << limit_level
<< ", " << GetLimitLevelDescription(limit_level) << ".";
return false;
}
#endif
return true;
}
bool GetMaxSampleFrequency(uint64_t* max_sample_freq) {
std::string s;
if (!android::base::ReadFileToString("/proc/sys/kernel/perf_event_max_sample_rate", &s)) {
PLOG(DEBUG) << "failed to read /proc/sys/kernel/perf_event_max_sample_rate";
return false;
}
s = android::base::Trim(s);
if (!android::base::ParseUint(s.c_str(), max_sample_freq)) {
LOG(ERROR) << "failed to parse /proc/sys/kernel/perf_event_max_sample_rate: " << s;
return false;
}
return true;
}
bool CheckKernelSymbolAddresses() {
const std::string kptr_restrict_file = "/proc/sys/kernel/kptr_restrict";
std::string s;
if (!android::base::ReadFileToString(kptr_restrict_file, &s)) {
PLOG(DEBUG) << "failed to read " << kptr_restrict_file;
return false;
}
s = android::base::Trim(s);
int value;
if (!android::base::ParseInt(s.c_str(), &value)) {
LOG(ERROR) << "failed to parse " << kptr_restrict_file << ": " << s;
return false;
}
// Accessible to everyone?
if (value == 0) {
return true;
}
// Accessible to root?
if (value == 1 && IsRoot()) {
return true;
}
// Can we make it accessible to us?
if (IsRoot() && android::base::WriteStringToFile("1", kptr_restrict_file)) {
return true;
}
LOG(WARNING) << "Access to kernel symbol addresses is restricted. If "
<< "possible, please do `echo 0 >/proc/sys/kernel/kptr_restrict` "
<< "to fix this.";
return false;
}
ArchType GetMachineArch() {
utsname uname_buf;
if (TEMP_FAILURE_RETRY(uname(&uname_buf)) != 0) {
PLOG(WARNING) << "uname() failed";
return GetBuildArch();
}
ArchType arch = GetArchType(uname_buf.machine);
if (arch != ARCH_UNSUPPORTED) {
return arch;
}
return GetBuildArch();
}
void PrepareVdsoFile() {
// vdso is an elf file in memory loaded in each process's user space by the kernel. To read
// symbols from it and unwind through it, we need to dump it into a file in storage.
// It doesn't affect much when failed to prepare vdso file, so there is no need to return values.
std::vector<ThreadMmap> thread_mmaps;
if (!GetThreadMmapsInProcess(getpid(), &thread_mmaps)) {
return;
}
const ThreadMmap* vdso_map = nullptr;
for (const auto& map : thread_mmaps) {
if (map.name == "[vdso]") {
vdso_map = ↦
break;
}
}
if (vdso_map == nullptr) {
return;
}
std::string s(vdso_map->len, '\0');
memcpy(&s[0], reinterpret_cast<void*>(static_cast<uintptr_t>(vdso_map->start_addr)),
vdso_map->len);
std::unique_ptr<TemporaryFile> tmpfile = ScopedTempFiles::CreateTempFile();
if (!android::base::WriteStringToFd(s, tmpfile->release())) {
return;
}
Dso::SetVdsoFile(tmpfile->path, sizeof(size_t) == sizeof(uint64_t));
}
static bool HasOpenedAppApkFile(int pid) {
std::string fd_path = "/proc/" + std::to_string(pid) + "/fd/";
std::vector<std::string> files = GetEntriesInDir(fd_path);
for (const auto& file : files) {
std::string real_path;
if (!android::base::Readlink(fd_path + file, &real_path)) {
continue;
}
if (real_path.find("app") != std::string::npos && real_path.find(".apk") != std::string::npos) {
return true;
}
}
return false;
}
std::set<pid_t> WaitForAppProcesses(const std::string& package_name) {
std::set<pid_t> result;
size_t loop_count = 0;
while (true) {
std::vector<pid_t> pids = GetAllProcesses();
for (pid_t pid : pids) {
std::string cmdline;
if (!android::base::ReadFileToString("/proc/" + std::to_string(pid) + "/cmdline", &cmdline)) {
// Maybe we don't have permission to read it.
continue;
}
std::string process_name = android::base::Basename(cmdline);
// The app may have multiple processes, with process name like
// com.google.android.googlequicksearchbox:search.
size_t split_pos = process_name.find(':');
if (split_pos != std::string::npos) {
process_name = process_name.substr(0, split_pos);
}
if (process_name != package_name) {
continue;
}
// If a debuggable app with wrap.sh runs on Android O, the app will be started with
// logwrapper as below:
// 1. Zygote forks a child process, rename it to package_name.
// 2. The child process execute sh, which starts a child process running
// /system/bin/logwrapper.
// 3. logwrapper starts a child process running sh, which interprets wrap.sh.
// 4. wrap.sh starts a child process running the app.
// The problem here is we want to profile the process started in step 4, but sometimes we
// run into the process started in step 1. To solve it, we can check if the process has
// opened an apk file in some app dirs.
if (!HasOpenedAppApkFile(pid)) {
continue;
}
if (loop_count > 0u) {
LOG(INFO) << "Got process " << pid << " for package " << package_name;
}
result.insert(pid);
}
if (!result.empty()) {
return result;
}
if (++loop_count == 1u) {
LOG(INFO) << "Waiting for process of app " << package_name;
}
usleep(1000);
}
}
class ScopedFile {
public:
ScopedFile(const std::string& filepath, const std::string& app_package_name = "")
: filepath_(filepath), app_package_name_(app_package_name) {}
~ScopedFile() {
if (app_package_name_.empty()) {
unlink(filepath_.c_str());
} else {
Workload::RunCmd({"run-as", app_package_name_, "rm", "-rf", filepath_});
}
}
private:
std::string filepath_;
std::string app_package_name_;
};
bool RunInAppContext(const std::string& app_package_name, const std::string& cmd,
const std::vector<std::string>& args, size_t workload_args_size,
const std::string& output_filepath, bool need_tracepoint_events) {
// 1. Test if the package exists.
if (!Workload::RunCmd({"run-as", app_package_name, "echo", ">/dev/null"}, false)) {
LOG(ERROR) << "Package " << app_package_name << " doesn't exist or isn't debuggable.";
return false;
}
// 2. Copy simpleperf binary to the package. Create tracepoint_file if needed.
std::string simpleperf_path;
if (!android::base::Readlink("/proc/self/exe", &simpleperf_path)) {
PLOG(ERROR) << "ReadLink failed";
return false;
}
if (!Workload::RunCmd({"run-as", app_package_name, "cp", simpleperf_path, "simpleperf"})) {
return false;
}
ScopedFile scoped_simpleperf("simpleperf", app_package_name);
std::unique_ptr<ScopedFile> scoped_tracepoint_file;
const std::string tracepoint_file = "/data/local/tmp/tracepoint_events";
if (need_tracepoint_events) {
// Since we can't read tracepoint events from tracefs in app's context, we need to prepare
// them in tracepoint_file in shell's context, and pass the path of tracepoint_file to the
// child process using --tracepoint-events option.
if (!android::base::WriteStringToFile(GetTracepointEvents(), tracepoint_file)) {
PLOG(ERROR) << "Failed to store tracepoint events";
return false;
}
scoped_tracepoint_file.reset(new ScopedFile(tracepoint_file));
}
// 3. Prepare to start child process to profile.
std::string output_basename = output_filepath.empty() ? "" :
android::base::Basename(output_filepath);
std::vector<std::string> new_args =
{"run-as", app_package_name, "./simpleperf", cmd, "--in-app", "--log", GetLogSeverityName()};
if (need_tracepoint_events) {
new_args.push_back("--tracepoint-events");
new_args.push_back(tracepoint_file);
}
for (size_t i = 0; i < args.size(); ++i) {
if (i >= args.size() - workload_args_size || args[i] != "-o") {
new_args.push_back(args[i]);
} else {
new_args.push_back(args[i++]);
new_args.push_back(output_basename);
}
}
std::unique_ptr<Workload> workload = Workload::CreateWorkload(new_args);
if (!workload) {
return false;
}
IOEventLoop loop;
bool need_to_kill_child = false;
if (!loop.AddSignalEvents({SIGINT, SIGTERM, SIGHUP},
[&]() { need_to_kill_child = true; return loop.ExitLoop(); })) {
return false;
}
if (!loop.AddSignalEvent(SIGCHLD, [&]() { return loop.ExitLoop(); })) {
return false;
}
// 4. Create child process to run run-as, and wait for the child process.
if (!workload->Start()) {
return false;
}
if (!loop.RunLoop()) {
return false;
}
if (need_to_kill_child) {
// The child process can exit before we kill it, so don't report kill errors.
Workload::RunCmd({"run-as", app_package_name, "pkill", "simpleperf"}, false);
}
int exit_code;
if (!workload->WaitChildProcess(&exit_code) || exit_code != 0) {
return false;
}
// 5. If there is any output file, copy it from the app's directory.
if (!output_filepath.empty()) {
if (!Workload::RunCmd({"run-as", app_package_name, "cat", output_basename,
">" + output_filepath})) {
return false;
}
if (!Workload::RunCmd({"run-as", app_package_name, "rm", output_basename})) {
return false;
}
}
return true;
}
static std::string default_package_name;
void SetDefaultAppPackageName(const std::string& package_name) {
default_package_name = package_name;
}
const std::string& GetDefaultAppPackageName() {
return default_package_name;
}
void AllowMoreOpenedFiles() {
// On Android <= O, the hard limit is 4096, and the soft limit is 1024.
// On Android >= P, both the hard and soft limit are 32768.
rlimit limit;
if (getrlimit(RLIMIT_NOFILE, &limit) == 0) {
limit.rlim_cur = limit.rlim_max;
setrlimit(RLIMIT_NOFILE, &limit);
}
}
std::string ScopedTempFiles::tmp_dir_;
std::vector<std::string> ScopedTempFiles::files_to_delete_;
ScopedTempFiles::ScopedTempFiles(const std::string& tmp_dir) {
CHECK(tmp_dir_.empty()); // No other ScopedTempFiles.
tmp_dir_ = tmp_dir;
}
ScopedTempFiles::~ScopedTempFiles() {
tmp_dir_.clear();
for (auto& file : files_to_delete_) {
unlink(file.c_str());
}
files_to_delete_.clear();
}
std::unique_ptr<TemporaryFile> ScopedTempFiles::CreateTempFile(bool delete_in_destructor) {
CHECK(!tmp_dir_.empty());
std::unique_ptr<TemporaryFile> tmp_file(new TemporaryFile(tmp_dir_));
CHECK_NE(tmp_file->fd, -1);
if (delete_in_destructor) {
files_to_delete_.push_back(tmp_file->path);
}
return tmp_file;
}
bool SignalIsIgnored(int signo) {
struct sigaction act;
if (sigaction(signo, nullptr, &act) != 0) {
PLOG(FATAL) << "failed to query signal handler for signal " << signo;
}
if ((act.sa_flags & SA_SIGINFO)) {
return false;
}
return act.sa_handler == SIG_IGN;
}