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Diffstat (limited to 'libcorkscrew/backtrace.c')
| -rw-r--r-- | libcorkscrew/backtrace.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/libcorkscrew/backtrace.c b/libcorkscrew/backtrace.c new file mode 100644 index 0000000..b03c43f --- /dev/null +++ b/libcorkscrew/backtrace.c @@ -0,0 +1,205 @@ +/* + * 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); + } +} |