blob: 0348d7814c630a01706538848aabf1c2ad21b81d [file] [log] [blame]
/*
* Copyright (C) 2013 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 <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <unistd.h>
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <string>
#include <backtrace/Backtrace.h>
#include <cutils/log.h>
#include "Backtrace.h"
#include "thread_utils.h"
//-------------------------------------------------------------------------
// BacktraceImpl functions.
//-------------------------------------------------------------------------
backtrace_t* BacktraceImpl::GetBacktraceData() {
return &backtrace_obj_->backtrace_;
}
//-------------------------------------------------------------------------
// Backtrace functions.
//-------------------------------------------------------------------------
Backtrace::Backtrace(BacktraceImpl* impl) : impl_(impl), map_info_(NULL) {
impl_->SetParent(this);
backtrace_.num_frames = 0;
backtrace_.pid = -1;
backtrace_.tid = -1;
}
Backtrace::~Backtrace() {
for (size_t i = 0; i < NumFrames(); i++) {
if (backtrace_.frames[i].func_name) {
free(backtrace_.frames[i].func_name);
backtrace_.frames[i].func_name = NULL;
}
}
if (map_info_) {
backtrace_destroy_map_info_list(map_info_);
map_info_ = NULL;
}
if (impl_) {
delete impl_;
impl_ = NULL;
}
}
bool Backtrace::Unwind(size_t num_ignore_frames) {
return impl_->Unwind(num_ignore_frames);
}
extern "C" char* __cxa_demangle(const char* mangled, char* buf, size_t* len,
int* status);
std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset) {
std::string func_name = impl_->GetFunctionNameRaw(pc, offset);
if (!func_name.empty()) {
#if defined(__APPLE__)
// Mac OS' __cxa_demangle demangles "f" as "float"; last tested on 10.7.
if (symbol_name[0] != '_') {
return func_name;
}
#endif
char* name = __cxa_demangle(func_name.c_str(), 0, 0, 0);
if (name) {
func_name = name;
free(name);
}
}
return func_name;
}
bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, uint32_t* out_value) {
if (ptr & 3) {
BACK_LOGW("invalid pointer %p", (void*)ptr);
*out_value = (uint32_t)-1;
return false;
}
return true;
}
const char* Backtrace::GetMapName(uintptr_t pc, uintptr_t* map_start) {
const backtrace_map_info_t* map_info = FindMapInfo(pc);
if (map_info) {
if (map_start) {
*map_start = map_info->start;
}
return map_info->name;
}
return NULL;
}
const backtrace_map_info_t* Backtrace::FindMapInfo(uintptr_t ptr) {
return backtrace_find_map_info(map_info_, ptr);
}
std::string Backtrace::FormatFrameData(size_t frame_num) {
backtrace_frame_data_t* frame = &backtrace_.frames[frame_num];
const char* map_name;
if (frame->map_name) {
map_name = frame->map_name;
} else {
map_name = "<unknown>";
}
uintptr_t relative_pc;
if (frame->map_offset) {
relative_pc = frame->map_offset;
} else {
relative_pc = frame->pc;
}
char buf[512];
if (frame->func_name && frame->func_offset) {
snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s+%" PRIuPTR ")",
frame_num, (int)sizeof(uintptr_t)*2, relative_pc, map_name,
frame->func_name, frame->func_offset);
} else if (frame->func_name) {
snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s)", frame_num,
(int)sizeof(uintptr_t)*2, relative_pc, map_name, frame->func_name);
} else {
snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s", frame_num,
(int)sizeof(uintptr_t)*2, relative_pc, map_name);
}
return buf;
}
//-------------------------------------------------------------------------
// BacktraceCurrent functions.
//-------------------------------------------------------------------------
BacktraceCurrent::BacktraceCurrent(BacktraceImpl* impl) : Backtrace(impl) {
map_info_ = backtrace_create_map_info_list(-1);
backtrace_.pid = getpid();
}
BacktraceCurrent::~BacktraceCurrent() {
}
bool BacktraceCurrent::ReadWord(uintptr_t ptr, uint32_t* out_value) {
if (!VerifyReadWordArgs(ptr, out_value)) {
return false;
}
const backtrace_map_info_t* map_info = FindMapInfo(ptr);
if (map_info && map_info->is_readable) {
*out_value = *reinterpret_cast<uint32_t*>(ptr);
return true;
} else {
BACK_LOGW("pointer %p not in a readable map", reinterpret_cast<void*>(ptr));
*out_value = static_cast<uint32_t>(-1);
return false;
}
}
//-------------------------------------------------------------------------
// BacktracePtrace functions.
//-------------------------------------------------------------------------
BacktracePtrace::BacktracePtrace(BacktraceImpl* impl, pid_t pid, pid_t tid)
: Backtrace(impl) {
map_info_ = backtrace_create_map_info_list(tid);
backtrace_.pid = pid;
backtrace_.tid = tid;
}
BacktracePtrace::~BacktracePtrace() {
}
bool BacktracePtrace::ReadWord(uintptr_t ptr, uint32_t* out_value) {
if (!VerifyReadWordArgs(ptr, out_value)) {
return false;
}
#if defined(__APPLE__)
BACK_LOGW("MacOS does not support reading from another pid.");
return false;
#else
// ptrace() returns -1 and sets errno when the operation fails.
// To disambiguate -1 from a valid result, we clear errno beforehand.
errno = 0;
*out_value = ptrace(PTRACE_PEEKTEXT, Tid(), reinterpret_cast<void*>(ptr), NULL);
if (*out_value == static_cast<uint32_t>(-1) && errno) {
BACK_LOGW("invalid pointer %p reading from tid %d, ptrace() strerror(errno)=%s",
reinterpret_cast<void*>(ptr), Tid(), strerror(errno));
return false;
}
return true;
#endif
}
Backtrace* Backtrace::Create(pid_t pid, pid_t tid) {
if (pid == BACKTRACE_CURRENT_PROCESS || pid == getpid()) {
if (tid == BACKTRACE_CURRENT_THREAD || tid == gettid()) {
return CreateCurrentObj();
} else {
return CreateThreadObj(tid);
}
} else if (tid == BACKTRACE_CURRENT_THREAD) {
return CreatePtraceObj(pid, pid);
} else {
return CreatePtraceObj(pid, tid);
}
}
//-------------------------------------------------------------------------
// Common interface functions.
//-------------------------------------------------------------------------
bool backtrace_create_context(
backtrace_context_t* context, pid_t pid, pid_t tid, size_t num_ignore_frames) {
Backtrace* backtrace = Backtrace::Create(pid, tid);
if (!backtrace) {
return false;
}
if (!backtrace->Unwind(num_ignore_frames)) {
delete backtrace;
return false;
}
context->data = backtrace;
context->backtrace = backtrace->GetBacktrace();
return true;
}
void backtrace_destroy_context(backtrace_context_t* context) {
if (context->data) {
Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
delete backtrace;
context->data = NULL;
}
context->backtrace = NULL;
}
const backtrace_t* backtrace_get_data(backtrace_context_t* context) {
if (context && context->data) {
Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
return backtrace->GetBacktrace();
}
return NULL;
}
bool backtrace_read_word(const backtrace_context_t* context, uintptr_t ptr, uint32_t* value) {
if (context->data) {
Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
return backtrace->ReadWord(ptr, value);
}
return true;
}
const char* backtrace_get_map_name(const backtrace_context_t* context, uintptr_t pc, uintptr_t* map_start) {
if (context->data) {
Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
return backtrace->GetMapName(pc, map_start);
}
return NULL;
}
char* backtrace_get_func_name(const backtrace_context_t* context, uintptr_t pc, uintptr_t* func_offset) {
if (context->data) {
Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
std::string func_name = backtrace->GetFunctionName(pc, func_offset);
if (!func_name.empty()) {
return strdup(func_name.c_str());
}
}
return NULL;
}
void backtrace_format_frame_data(
const backtrace_context_t* context, size_t frame_num, char* buf,
size_t buf_size) {
if (buf_size == 0 || buf == NULL) {
BACK_LOGW("bad call buf %p buf_size %zu", buf, buf_size);
} else if (context->data) {
Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
std::string line = backtrace->FormatFrameData(frame_num);
if (line.size() > buf_size) {
memcpy(buf, line.c_str(), buf_size-1);
buf[buf_size] = '\0';
} else {
memcpy(buf, line.c_str(), line.size()+1);
}
}
}