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/*
* Copyright (C) 2011 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.
*/
#define LOG_TAG "Corkscrew"
//#define LOG_NDEBUG 0
#include "backtrace-arch.h"
#include "backtrace-helper.h"
#include "ptrace-arch.h"
#include <corkscrew/map_info.h>
#include <corkscrew/symbol_table.h>
#include <corkscrew/ptrace.h>
#include <corkscrew/demangle.h>
#include <unistd.h>
#include <signal.h>
#include <pthread.h>
#include <unwind.h>
#include <sys/exec_elf.h>
#include <cutils/log.h>
#if HAVE_DLADDR
#include <dlfcn.h>
#endif
typedef struct {
backtrace_frame_t* backtrace;
size_t ignore_depth;
size_t max_depth;
size_t ignored_frames;
size_t returned_frames;
} backtrace_state_t;
static _Unwind_Reason_Code unwind_backtrace_callback(struct _Unwind_Context* context, void* arg) {
backtrace_state_t* state = (backtrace_state_t*)arg;
uintptr_t pc = _Unwind_GetIP(context);
if (pc) {
// TODO: Get information about the stack layout from the _Unwind_Context.
// This will require a new architecture-specific function to query
// the appropriate registers. Current callers of unwind_backtrace
// don't need this information, so we won't bother collecting it just yet.
add_backtrace_entry(pc, state->backtrace,
state->ignore_depth, state->max_depth,
&state->ignored_frames, &state->returned_frames);
}
return state->returned_frames < state->max_depth ? _URC_NO_REASON : _URC_END_OF_STACK;
}
ssize_t unwind_backtrace(backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
backtrace_state_t state;
state.backtrace = backtrace;
state.ignore_depth = ignore_depth;
state.max_depth = max_depth;
state.ignored_frames = 0;
state.returned_frames = 0;
_Unwind_Reason_Code rc =_Unwind_Backtrace(unwind_backtrace_callback, &state);
if (state.returned_frames) {
return state.returned_frames;
}
return rc == _URC_END_OF_STACK ? 0 : -1;
}
#ifdef CORKSCREW_HAVE_ARCH
static pthread_mutex_t g_unwind_signal_mutex = PTHREAD_MUTEX_INITIALIZER;
static volatile struct {
backtrace_frame_t* backtrace;
size_t ignore_depth;
size_t max_depth;
size_t returned_frames;
bool done;
} g_unwind_signal_state;
static void unwind_backtrace_thread_signal_handler(int n, siginfo_t* siginfo, void* sigcontext) {
backtrace_frame_t* backtrace = g_unwind_signal_state.backtrace;
if (backtrace) {
g_unwind_signal_state.backtrace = NULL;
g_unwind_signal_state.returned_frames = unwind_backtrace_signal_arch(
siginfo, sigcontext, backtrace,
g_unwind_signal_state.ignore_depth,
g_unwind_signal_state.max_depth);
g_unwind_signal_state.done = true;
}
}
#endif
ssize_t unwind_backtrace_thread(pid_t tid, backtrace_frame_t* backtrace,
size_t ignore_depth, size_t max_depth) {
#ifdef CORKSCREW_HAVE_ARCH
struct sigaction act;
struct sigaction oact;
memset(&act, 0, sizeof(act));
act.sa_sigaction = unwind_backtrace_thread_signal_handler;
act.sa_flags = SA_RESTART | SA_SIGINFO;
sigemptyset(&act.sa_mask);
pthread_mutex_lock(&g_unwind_signal_mutex);
g_unwind_signal_state.backtrace = backtrace;
g_unwind_signal_state.ignore_depth = ignore_depth;
g_unwind_signal_state.max_depth = max_depth;
g_unwind_signal_state.returned_frames = 0;
g_unwind_signal_state.done = false;
ssize_t frames = -1;
if (!sigaction(SIGURG, &act, &oact)) {
if (!kill(tid, SIGURG)) {
while (!g_unwind_signal_state.done) {
usleep(1000);
}
frames = g_unwind_signal_state.returned_frames;
}
sigaction(SIGURG, &oact, NULL);
}
g_unwind_signal_state.backtrace = NULL;
pthread_mutex_unlock(&g_unwind_signal_mutex);
return frames;
#else
return -1;
#endif
}
ssize_t unwind_backtrace_ptrace(pid_t tid, const ptrace_context_t* context,
backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
#ifdef CORKSCREW_HAVE_ARCH
return unwind_backtrace_ptrace_arch(tid, context, backtrace, ignore_depth, max_depth);
#else
return -1;
#endif
}
static void init_backtrace_symbol(backtrace_symbol_t* symbol, uintptr_t pc) {
symbol->relative_pc = pc;
symbol->map_info = NULL;
symbol->name = NULL;
symbol->demangled_name = NULL;
}
void get_backtrace_symbols(const backtrace_frame_t* backtrace, size_t frames,
backtrace_symbol_t* backtrace_symbols) {
const map_info_t* milist = my_map_info_list();
for (size_t i = 0; i < frames; i++) {
const backtrace_frame_t* frame = &backtrace[i];
backtrace_symbol_t* symbol = &backtrace_symbols[i];
init_backtrace_symbol(symbol, frame->absolute_pc);
const map_info_t* mi = find_map_info(milist, frame->absolute_pc);
if (mi) {
symbol->relative_pc = frame->absolute_pc - mi->start;
symbol->map_info = mi;
#if HAVE_DLADDR
Dl_info info;
if (dladdr((const void*)frame->absolute_pc, &info) && info.dli_sname) {
symbol->name = info.dli_sname;
symbol->demangled_name = demangle_symbol_name(symbol->name);
}
#endif
}
}
}
void get_backtrace_symbols_ptrace(const ptrace_context_t* context,
const backtrace_frame_t* backtrace, size_t frames,
backtrace_symbol_t* backtrace_symbols) {
for (size_t i = 0; i < frames; i++) {
const backtrace_frame_t* frame = &backtrace[i];
backtrace_symbol_t* symbol = &backtrace_symbols[i];
init_backtrace_symbol(symbol, frame->absolute_pc);
const map_info_t* mi;
const symbol_t* s;
find_symbol_ptrace(context, frame->absolute_pc, &mi, &s);
if (mi) {
symbol->relative_pc = frame->absolute_pc - mi->start;
symbol->map_info = mi;
}
if (s) {
symbol->name = s->name;
symbol->demangled_name = demangle_symbol_name(symbol->name);
}
}
}
void free_backtrace_symbols(backtrace_symbol_t* backtrace_symbols, size_t frames) {
for (size_t i = 0; i < frames; i++) {
backtrace_symbol_t* symbol = &backtrace_symbols[i];
free(symbol->demangled_name);
init_backtrace_symbol(symbol, 0);
}
}
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