/*
* 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 <dirent.h>
#include <poll.h>
#include <sys/prctl.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <csignal>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <thread>
#include <memory>
#include <set>
#include <string>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/macros.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
namespace art {
namespace {
using android::base::StringPrintf;
using android::base::unique_fd;
constexpr bool kUseAddr2line = true;
namespace timeout_signal {
class SignalSet {
public:
SignalSet() {
if (sigemptyset(&set_) == -1) {
PLOG(FATAL) << "sigemptyset failed";
}
}
void Add(int signal) {
if (sigaddset(&set_, signal) == -1) {
PLOG(FATAL) << "sigaddset " << signal << " failed";
}
}
void Block() {
if (pthread_sigmask(SIG_BLOCK, &set_, nullptr) != 0) {
PLOG(FATAL) << "pthread_sigmask failed";
}
}
int Wait() {
// Sleep in sigwait() until a signal arrives. gdb causes EINTR failures.
int signal_number;
int rc = TEMP_FAILURE_RETRY(sigwait(&set_, &signal_number));
if (rc != 0) {
PLOG(FATAL) << "sigwait failed";
}
return signal_number;
}
private:
sigset_t set_;
};
int GetTimeoutSignal() {
return SIGRTMIN + 2;
}
} // namespace timeout_signal
namespace addr2line {
constexpr const char* kAddr2linePath =
"/prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.17-4.8/bin/x86_64-linux-addr2line";
std::unique_ptr<std::string> FindAddr2line() {
const char* env_value = getenv("ANDROID_BUILD_TOP");
if (env_value != nullptr) {
std::string path = std::string(env_value) + kAddr2linePath;
if (access(path.c_str(), X_OK) == 0) {
return std::make_unique<std::string>(path);
}
}
{
std::string path = std::string(".") + kAddr2linePath;
if (access(path.c_str(), X_OK) == 0) {
return std::make_unique<std::string>(path);
}
}
{
using android::base::Dirname;
std::string exec_dir = android::base::GetExecutableDirectory();
std::string derived_top = Dirname(Dirname(Dirname(Dirname(exec_dir))));
std::string path = derived_top + kAddr2linePath;
if (access(path.c_str(), X_OK) == 0) {
return std::make_unique<std::string>(path);
}
}
constexpr const char* kHostAddr2line = "/usr/bin/addr2line";
if (access(kHostAddr2line, F_OK) == 0) {
return std::make_unique<std::string>(kHostAddr2line);
}
return nullptr;
}
// The state of an open pipe to addr2line. In "server" mode, addr2line takes input on stdin
// and prints the result to stdout. This struct keeps the state of the open connection.
struct Addr2linePipe {
Addr2linePipe(int in_fd, int out_fd, const std::string& file_name, pid_t pid)
: in(in_fd), out(out_fd), file(file_name), child_pid(pid), odd(true) {}
~Addr2linePipe() {
kill(child_pid, SIGKILL);
}
unique_fd in; // The file descriptor that is connected to the output of addr2line.
unique_fd out; // The file descriptor that is connected to the input of addr2line.
const std::string file; // The file addr2line is working on, so that we know when to close
// and restart.
const pid_t child_pid; // The pid of the child, which we should kill when we're done.
bool odd; // Print state for indentation of lines.
};
std::unique_ptr<Addr2linePipe> Connect(const std::string& name, const char* args[]) {
int caller_to_addr2line[2];
int addr2line_to_caller[2];
if (pipe(caller_to_addr2line) == -1) {
return nullptr;
}
if (pipe(addr2line_to_caller) == -1) {
close(caller_to_addr2line[0]);
close(caller_to_addr2line[1]);
return nullptr;
}
pid_t pid = fork();
if (pid == -1) {
close(caller_to_addr2line[0]);
close(caller_to_addr2line[1]);
close(addr2line_to_caller[0]);
close(addr2line_to_caller[1]);
return nullptr;
}
if (pid == 0) {
dup2(caller_to_addr2line[0], STDIN_FILENO);
dup2(addr2line_to_caller[1], STDOUT_FILENO);
close(caller_to_addr2line[0]);
close(caller_to_addr2line[1]);
close(addr2line_to_caller[0]);
close(addr2line_to_caller[1]);
execv(args[0], const_cast<char* const*>(args));
exit(1);
} else {
close(caller_to_addr2line[0]);
close(addr2line_to_caller[1]);
return std::make_unique<Addr2linePipe>(addr2line_to_caller[0],
caller_to_addr2line[1],
name,
pid);
}
}
void WritePrefix(std::ostream& os, const char* prefix, bool odd) {
if (prefix != nullptr) {
os << prefix;
}
os << " ";
if (!odd) {
os << " ";
}
}
void Drain(size_t expected,
const char* prefix,
std::unique_ptr<Addr2linePipe>* pipe /* inout */,
std::ostream& os) {
DCHECK(pipe != nullptr);
DCHECK(pipe->get() != nullptr);
int in = pipe->get()->in.get();
DCHECK_GE(in, 0);
bool prefix_written = false;
for (;;) {
constexpr uint32_t kWaitTimeExpectedMilli = 500;
constexpr uint32_t kWaitTimeUnexpectedMilli = 50;
int timeout = expected > 0 ? kWaitTimeExpectedMilli : kWaitTimeUnexpectedMilli;
struct pollfd read_fd{in, POLLIN, 0};
int retval = TEMP_FAILURE_RETRY(poll(&read_fd, 1, timeout));
if (retval == -1) {
// An error occurred.
pipe->reset();
return;
}
if (retval == 0) {
// Timeout.
return;
}
if (!(read_fd.revents & POLLIN)) {
// addr2line call exited.
pipe->reset();
return;
}
constexpr size_t kMaxBuffer = 128; // Relatively small buffer. Should be OK as we're on an
// alt stack, but just to be sure...
char buffer[kMaxBuffer];
memset(buffer, 0, kMaxBuffer);
int bytes_read = TEMP_FAILURE_RETRY(read(in, buffer, kMaxBuffer - 1));
if (bytes_read <= 0) {
// This should not really happen...
pipe->reset();
return;
}
buffer[bytes_read] = '\0';
char* tmp = buffer;
while (*tmp != 0) {
if (!prefix_written) {
WritePrefix(os, prefix, (*pipe)->odd);
prefix_written = true;
}
char* new_line = strchr(tmp, '\n');
if (new_line == nullptr) {
os << tmp;
break;
} else {
os << std::string(tmp, new_line - tmp + 1);
tmp = new_line + 1;
prefix_written = false;
(*pipe)->odd = !(*pipe)->odd;
if (expected > 0) {
expected--;
}
}
}
}
}
void Addr2line(const std::string& addr2line,
const std::string& map_src,
uintptr_t offset,
std::ostream& os,
const char* prefix,
std::unique_ptr<Addr2linePipe>* pipe /* inout */) {
DCHECK(pipe != nullptr);
if (map_src == "[vdso]" || android::base::EndsWith(map_src, ".vdex")) {
// addr2line will not work on the vdso.
// vdex files are special frames injected for the interpreter
// so they don't have any line number information available.
return;
}
if (*pipe == nullptr || (*pipe)->file != map_src) {
if (*pipe != nullptr) {
Drain(0, prefix, pipe, os);
}
pipe->reset(); // Close early.
const char* args[] = {
addr2line.c_str(),
"--functions",
"--inlines",
"--demangle",
"-e",
map_src.c_str(),
nullptr
};
*pipe = Connect(map_src, args);
}
Addr2linePipe* pipe_ptr = pipe->get();
if (pipe_ptr == nullptr) {
// Failed...
return;
}
// Send the offset.
const std::string hex_offset = StringPrintf("%zx\n", offset);
if (!android::base::WriteFully(pipe_ptr->out.get(), hex_offset.data(), hex_offset.length())) {
// Error. :-(
pipe->reset();
return;
}
// Now drain (expecting two lines).
Drain(2U, prefix, pipe, os);
}
} // namespace addr2line
namespace ptrace {
std::set<pid_t> PtraceSiblings(pid_t pid) {
std::set<pid_t> ret;
std::string task_path = android::base::StringPrintf("/proc/%d/task", pid);
std::unique_ptr<DIR, int (*)(DIR*)> d(opendir(task_path.c_str()), closedir);
// Bail early if the task directory cannot be opened.
if (d == nullptr) {
PLOG(ERROR) << "Failed to scan task folder";
return ret;
}
struct dirent* de;
while ((de = readdir(d.get())) != nullptr) {
// Ignore "." and "..".
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
continue;
}
char* end;
pid_t tid = strtoul(de->d_name, &end, 10);
if (*end) {
continue;
}
if (tid == pid) {
continue;
}
if (::ptrace(PTRACE_ATTACH, tid, 0, 0) != 0) {
PLOG(ERROR) << "Failed to attach to tid " << tid;
continue;
}
ret.insert(tid);
}
return ret;
}
void DumpABI(pid_t forked_pid) {
enum class ABI { kArm, kArm64, kMips, kMips64, kX86, kX86_64 };
#if defined(__arm__)
constexpr ABI kDumperABI = ABI::kArm;
#elif defined(__aarch64__)
constexpr ABI kDumperABI = ABI::kArm64;
#elif defined(__mips__) && !defined(__LP64__)
constexpr ABI kDumperABI = ABI::kMips;
#elif defined(__mips__) && defined(__LP64__)
constexpr ABI kDumperABI = ABI::kMips64;
#elif defined(__i386__)
constexpr ABI kDumperABI = ABI::kX86;
#elif defined(__x86_64__)
constexpr ABI kDumperABI = ABI::kX86_64;
#else
#error Unsupported architecture
#endif
char data[1024]; // Should be more than enough.
struct iovec io_vec;
io_vec.iov_base = &data;
io_vec.iov_len = 1024;
ABI to_print;
if (0 != ::ptrace(PTRACE_GETREGSET, forked_pid, /* NT_PRSTATUS */ 1, &io_vec)) {
LOG(ERROR) << "Could not get registers to determine abi.";
// Use 64-bit as default.
switch (kDumperABI) {
case ABI::kArm:
case ABI::kArm64:
to_print = ABI::kArm64;
break;
case ABI::kMips:
case ABI::kMips64:
to_print = ABI::kMips64;
break;
case ABI::kX86:
case ABI::kX86_64:
to_print = ABI::kX86_64;
break;
default:
__builtin_unreachable();
}
} else {
// Check the length of the data. Assume that it's the same arch as the tool.
switch (kDumperABI) {
case ABI::kArm:
case ABI::kArm64:
to_print = io_vec.iov_len == 18 * sizeof(uint32_t) ? ABI::kArm : ABI::kArm64;
break;
case ABI::kMips:
case ABI::kMips64:
to_print = ABI::kMips64; // TODO Figure out how this should work.
break;
case ABI::kX86:
case ABI::kX86_64:
to_print = io_vec.iov_len == 17 * sizeof(uint32_t) ? ABI::kX86 : ABI::kX86_64;
break;
default:
__builtin_unreachable();
}
}
std::string abi_str;
switch (to_print) {
case ABI::kArm:
abi_str = "arm";
break;
case ABI::kArm64:
abi_str = "arm64";
break;
case ABI::kMips:
abi_str = "mips";
break;
case ABI::kMips64:
abi_str = "mips64";
break;
case ABI::kX86:
abi_str = "x86";
break;
case ABI::kX86_64:
abi_str = "x86_64";
break;
}
std::cerr << "ABI: '" << abi_str << "'" << std::endl;
}
} // namespace ptrace
template <typename T>
bool WaitLoop(uint32_t max_wait_micros, const T& handler) {
constexpr uint32_t kWaitMicros = 10;
const size_t kMaxLoopCount = max_wait_micros / kWaitMicros;
for (size_t loop_count = 1; loop_count <= kMaxLoopCount; ++loop_count) {
bool ret;
if (handler(&ret)) {
return ret;
}
usleep(kWaitMicros);
}
return false;
}
bool WaitForMainSigStop(const std::atomic<bool>& saw_wif_stopped_for_main) {
auto handler = [&](bool* res) {
if (saw_wif_stopped_for_main) {
*res = true;
return true;
}
return false;
};
constexpr uint32_t kMaxWaitMicros = 30 * 1000 * 1000; // 30s wait.
return WaitLoop(kMaxWaitMicros, handler);
}
bool WaitForSigStopped(pid_t pid, uint32_t max_wait_micros) {
auto handler = [&](bool* res) {
int status;
pid_t rc = TEMP_FAILURE_RETRY(waitpid(pid, &status, WNOHANG));
if (rc == -1) {
PLOG(ERROR) << "Failed to waitpid for " << pid;
*res = false;
return true;
}
if (rc == pid) {
if (!(WIFSTOPPED(status))) {
LOG(ERROR) << "Did not get expected stopped signal for " << pid;
*res = false;
} else {
*res = true;
}
return true;
}
return false;
};
return WaitLoop(max_wait_micros, handler);
}
#ifdef __LP64__
constexpr bool kIs64Bit = true;
#else
constexpr bool kIs64Bit = false;
#endif
void DumpThread(pid_t pid,
pid_t tid,
const std::string* addr2line_path,
const char* prefix,
BacktraceMap* map) {
// Use std::cerr to avoid the LOG prefix.
std::cerr << std::endl << "=== pid: " << pid << " tid: " << tid << " ===" << std::endl;
constexpr uint32_t kMaxWaitMicros = 1000 * 1000; // 1s.
if (pid != tid && !WaitForSigStopped(tid, kMaxWaitMicros)) {
LOG(ERROR) << "Failed to wait for sigstop on " << tid;
}
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, tid, map));
if (backtrace == nullptr) {
LOG(ERROR) << prefix << "(failed to create Backtrace for thread " << tid << ")";
return;
}
backtrace->SetSkipFrames(false);
if (!backtrace->Unwind(0, nullptr)) {
LOG(ERROR) << prefix << "(backtrace::Unwind failed for thread " << tid
<< ": " << backtrace->GetErrorString(backtrace->GetError()) << ")";
return;
}
if (backtrace->NumFrames() == 0) {
LOG(ERROR) << prefix << "(no native stack frames for thread " << tid << ")";
return;
}
std::unique_ptr<addr2line::Addr2linePipe> addr2line_state;
for (Backtrace::const_iterator it = backtrace->begin();
it != backtrace->end(); ++it) {
std::ostringstream oss;
oss << prefix << StringPrintf("#%02zu pc ", it->num);
bool try_addr2line = false;
if (!BacktraceMap::IsValid(it->map)) {
oss << StringPrintf(kIs64Bit ? "%016" PRIx64 " ???" : "%08" PRIx64 " ???", it->pc);
} else {
oss << StringPrintf(kIs64Bit ? "%016" PRIx64 " " : "%08" PRIx64 " ", it->rel_pc);
if (it->map.name.empty()) {
oss << StringPrintf("<anonymous:%" PRIx64 ">", it->map.start);
} else {
oss << it->map.name;
}
if (it->map.offset != 0) {
oss << StringPrintf(" (offset %" PRIx64 ")", it->map.offset);
}
oss << " (";
if (!it->func_name.empty()) {
oss << it->func_name;
if (it->func_offset != 0) {
oss << "+" << it->func_offset;
}
// Functions found using the gdb jit interface will be in an empty
// map that cannot be found using addr2line.
if (!it->map.name.empty()) {
try_addr2line = true;
}
} else {
oss << "???";
}
oss << ")";
}
std::cerr << oss.str() << std::endl;
if (try_addr2line && addr2line_path != nullptr) {
addr2line::Addr2line(*addr2line_path,
it->map.name,
it->rel_pc,
std::cerr,
prefix,
&addr2line_state);
}
}
if (addr2line_state != nullptr) {
addr2line::Drain(0, prefix, &addr2line_state, std::cerr);
}
}
void DumpProcess(pid_t forked_pid, const std::atomic<bool>& saw_wif_stopped_for_main) {
LOG(ERROR) << "Timeout for process " << forked_pid;
CHECK_EQ(0, ::ptrace(PTRACE_ATTACH, forked_pid, 0, 0));
std::set<pid_t> tids = ptrace::PtraceSiblings(forked_pid);
tids.insert(forked_pid);
ptrace::DumpABI(forked_pid);
// Check whether we have and should use addr2line.
std::unique_ptr<std::string> addr2line_path;
if (kUseAddr2line) {
addr2line_path = addr2line::FindAddr2line();
if (addr2line_path == nullptr) {
LOG(ERROR) << "Did not find usable addr2line";
}
}
if (!WaitForMainSigStop(saw_wif_stopped_for_main)) {
LOG(ERROR) << "Did not receive SIGSTOP for pid " << forked_pid;
}
std::unique_ptr<BacktraceMap> backtrace_map(BacktraceMap::Create(forked_pid));
if (backtrace_map == nullptr) {
LOG(ERROR) << "Could not create BacktraceMap";
return;
}
for (pid_t tid : tids) {
DumpThread(forked_pid, tid, addr2line_path.get(), " ", backtrace_map.get());
}
}
[[noreturn]]
void WaitMainLoop(pid_t forked_pid, std::atomic<bool>* saw_wif_stopped_for_main) {
for (;;) {
// Consider switching to waitid to not get woken up for WIFSTOPPED.
int status;
pid_t res = TEMP_FAILURE_RETRY(waitpid(forked_pid, &status, 0));
if (res == -1) {
PLOG(FATAL) << "Failure during waitpid";
__builtin_unreachable();
}
if (WIFEXITED(status)) {
_exit(WEXITSTATUS(status));
__builtin_unreachable();
}
if (WIFSIGNALED(status)) {
_exit(1);
__builtin_unreachable();
}
if (WIFSTOPPED(status)) {
*saw_wif_stopped_for_main = true;
continue;
}
if (WIFCONTINUED(status)) {
continue;
}
LOG(FATAL) << "Unknown status " << std::hex << status;
}
}
[[noreturn]]
void SetupAndWait(pid_t forked_pid) {
timeout_signal::SignalSet signals;
signals.Add(timeout_signal::GetTimeoutSignal());
signals.Block();
std::atomic<bool> saw_wif_stopped_for_main(false);
std::thread signal_catcher([&]() {
signals.Block();
int sig = signals.Wait();
CHECK_EQ(sig, timeout_signal::GetTimeoutSignal());
DumpProcess(forked_pid, saw_wif_stopped_for_main);
// Don't clean up. Just kill the child and exit.
kill(forked_pid, SIGKILL);
_exit(1);
});
WaitMainLoop(forked_pid, &saw_wif_stopped_for_main);
}
} // namespace
} // namespace art
int main(int argc ATTRIBUTE_UNUSED, char** argv) {
pid_t orig_ppid = getpid();
pid_t pid = fork();
if (pid == 0) {
if (prctl(PR_SET_PDEATHSIG, SIGTERM) == -1) {
_exit(1);
}
if (getppid() != orig_ppid) {
_exit(2);
}
execvp(argv[1], &argv[1]);
_exit(3);
__builtin_unreachable();
}
art::SetupAndWait(pid);
__builtin_unreachable();
}