/*
* Copyright (C) 2016 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 "native_stack_dump.h"
#include <ostream>
#include <stdio.h>
#include "art_method.h"
// For DumpNativeStack.
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
#if defined(__linux__)
#include <memory>
#include <vector>
#include <linux/unistd.h>
#include <poll.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/types.h>
#include "android-base/stringprintf.h"
#include "android-base/strings.h"
#include "arch/instruction_set.h"
#include "base/aborting.h"
#include "base/file_utils.h"
#include "base/memory_tool.h"
#include "base/mutex.h"
#include "base/os.h"
#include "base/unix_file/fd_file.h"
#include "base/utils.h"
#include "oat_quick_method_header.h"
#include "thread-current-inl.h"
#endif
namespace art {
#if defined(__linux__)
using android::base::StringPrintf;
static constexpr bool kUseAddr2line = !kIsTargetBuild;
ALWAYS_INLINE
static inline void WritePrefix(std::ostream& os, const char* prefix, bool odd) {
if (prefix != nullptr) {
os << prefix;
}
os << " ";
if (!odd) {
os << " ";
}
}
// 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, false), out(out_fd, false), file(file_name), child_pid(pid), odd(true) {}
~Addr2linePipe() {
kill(child_pid, SIGKILL);
}
File in; // The file descriptor that is connected to the output of addr2line.
File 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.
};
static 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::unique_ptr<Addr2linePipe>(new Addr2linePipe(addr2line_to_caller[0],
caller_to_addr2line[1],
name,
pid));
}
}
static 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.Fd();
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 {
char saved = *(new_line + 1);
*(new_line + 1) = 0;
os << tmp;
*(new_line + 1) = saved;
tmp = new_line + 1;
prefix_written = false;
(*pipe)->odd = !(*pipe)->odd;
if (expected > 0) {
expected--;
}
}
}
}
}
static void 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[7] = {
"/usr/bin/addr2line",
"--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 (!pipe_ptr->out.WriteFully(hex_offset.data(), hex_offset.length())) {
// Error. :-(
pipe->reset();
return;
}
// Now drain (expecting two lines).
Drain(2U, prefix, pipe, os);
}
static bool RunCommand(const std::string& cmd) {
FILE* stream = popen(cmd.c_str(), "r");
if (stream) {
pclose(stream);
return true;
} else {
return false;
}
}
static bool PcIsWithinQuickCode(ArtMethod* method, uintptr_t pc) NO_THREAD_SAFETY_ANALYSIS {
uintptr_t code = reinterpret_cast<uintptr_t>(EntryPointToCodePointer(
method->GetEntryPointFromQuickCompiledCode()));
if (code == 0) {
return pc == 0;
}
uintptr_t code_size = reinterpret_cast<const OatQuickMethodHeader*>(code)[-1].GetCodeSize();
return code <= pc && pc <= (code + code_size);
}
void DumpNativeStack(std::ostream& os,
pid_t tid,
BacktraceMap* existing_map,
const char* prefix,
ArtMethod* current_method,
void* ucontext_ptr,
bool skip_frames) {
// b/18119146
if (RUNNING_ON_MEMORY_TOOL != 0) {
return;
}
BacktraceMap* map = existing_map;
std::unique_ptr<BacktraceMap> tmp_map;
if (map == nullptr) {
tmp_map.reset(BacktraceMap::Create(getpid()));
map = tmp_map.get();
}
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS, tid, map));
backtrace->SetSkipFrames(skip_frames);
if (!backtrace->Unwind(0, reinterpret_cast<ucontext*>(ucontext_ptr))) {
os << prefix << "(backtrace::Unwind failed for thread " << tid
<< ": " << backtrace->GetErrorString(backtrace->GetError()) << ")" << std::endl;
return;
} else if (backtrace->NumFrames() == 0) {
os << prefix << "(no native stack frames for thread " << tid << ")" << std::endl;
return;
}
// Check whether we have and should use addr2line.
bool use_addr2line;
if (kUseAddr2line) {
// Try to run it to see whether we have it. Push an argument so that it doesn't assume a.out
// and print to stderr.
use_addr2line = (gAborting > 0) && RunCommand("addr2line -h");
} else {
use_addr2line = false;
}
std::unique_ptr<Addr2linePipe> addr2line_state;
for (Backtrace::const_iterator it = backtrace->begin();
it != backtrace->end(); ++it) {
// We produce output like this:
// ] #00 pc 000075bb8 /system/lib/libc.so (unwind_backtrace_thread+536)
// In order for parsing tools to continue to function, the stack dump
// format must at least adhere to this format:
// #XX pc <RELATIVE_ADDR> <FULL_PATH_TO_SHARED_LIBRARY> ...
// The parsers require a single space before and after pc, and two spaces
// after the <RELATIVE_ADDR>. There can be any prefix data before the
// #XX. <RELATIVE_ADDR> has to be a hex number but with no 0x prefix.
os << prefix << StringPrintf("#%02zu pc ", it->num);
bool try_addr2line = false;
if (!BacktraceMap::IsValid(it->map)) {
os << StringPrintf(Is64BitInstructionSet(kRuntimeISA) ? "%016" PRIx64 " ???"
: "%08" PRIx64 " ???",
it->pc);
} else {
os << StringPrintf(Is64BitInstructionSet(kRuntimeISA) ? "%016" PRIx64 " "
: "%08" PRIx64 " ",
it->rel_pc);
if (it->map.name.empty()) {
os << StringPrintf("<anonymous:%" PRIx64 ">", it->map.start);
} else {
os << it->map.name;
}
if (it->map.offset != 0) {
os << StringPrintf(" (offset %" PRIx64 ")", it->map.offset);
}
os << " (";
if (!it->func_name.empty()) {
os << it->func_name;
if (it->func_offset != 0) {
os << "+" << 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 if (current_method != nullptr &&
Locks::mutator_lock_->IsSharedHeld(Thread::Current()) &&
PcIsWithinQuickCode(current_method, it->pc)) {
const void* start_of_code = current_method->GetEntryPointFromQuickCompiledCode();
os << current_method->JniLongName() << "+"
<< (it->pc - reinterpret_cast<uint64_t>(start_of_code));
} else {
os << "???";
}
os << ")";
}
os << std::endl;
if (try_addr2line && use_addr2line) {
Addr2line(it->map.name, it->pc - it->map.start, os, prefix, &addr2line_state);
}
}
if (addr2line_state != nullptr) {
Drain(0, prefix, &addr2line_state, os);
}
}
void DumpKernelStack(std::ostream& os, pid_t tid, const char* prefix, bool include_count) {
if (tid == GetTid()) {
// There's no point showing that we're reading our stack out of /proc!
return;
}
std::string kernel_stack_filename(StringPrintf("/proc/self/task/%d/stack", tid));
std::string kernel_stack;
if (!ReadFileToString(kernel_stack_filename, &kernel_stack)) {
os << prefix << "(couldn't read " << kernel_stack_filename << ")\n";
return;
}
std::vector<std::string> kernel_stack_frames;
Split(kernel_stack, '\n', &kernel_stack_frames);
if (kernel_stack_frames.empty()) {
os << prefix << "(" << kernel_stack_filename << " is empty)\n";
return;
}
// We skip the last stack frame because it's always equivalent to "[<ffffffff>] 0xffffffff",
// which looking at the source appears to be the kernel's way of saying "that's all, folks!".
kernel_stack_frames.pop_back();
for (size_t i = 0; i < kernel_stack_frames.size(); ++i) {
// Turn "[<ffffffff8109156d>] futex_wait_queue_me+0xcd/0x110"
// into "futex_wait_queue_me+0xcd/0x110".
const char* text = kernel_stack_frames[i].c_str();
const char* close_bracket = strchr(text, ']');
if (close_bracket != nullptr) {
text = close_bracket + 2;
}
os << prefix;
if (include_count) {
os << StringPrintf("#%02zd ", i);
}
os << text << std::endl;
}
}
#elif defined(__APPLE__)
void DumpNativeStack(std::ostream& os ATTRIBUTE_UNUSED,
pid_t tid ATTRIBUTE_UNUSED,
BacktraceMap* existing_map ATTRIBUTE_UNUSED,
const char* prefix ATTRIBUTE_UNUSED,
ArtMethod* current_method ATTRIBUTE_UNUSED,
void* ucontext_ptr ATTRIBUTE_UNUSED,
bool skip_frames ATTRIBUTE_UNUSED) {
}
void DumpKernelStack(std::ostream& os ATTRIBUTE_UNUSED,
pid_t tid ATTRIBUTE_UNUSED,
const char* prefix ATTRIBUTE_UNUSED,
bool include_count ATTRIBUTE_UNUSED) {
}
#else
#error "Unsupported architecture for native stack dumps."
#endif
} // namespace art