static ssize_t coffeecatch_backtrace_signal(siginfo_t* si, void* sc,
backtrace_frame_t* frames,
size_t ignore_depth,
size_t max_depth) {
void *const libcorkscrew = dlopen("libcorkscrew.so", RTLD_LAZY | RTLD_LOCAL);
if (libcorkscrew != NULL) {
t_unwind_backtrace_signal_arch unwind_backtrace_signal_arch
= (t_unwind_backtrace_signal_arch)
dlsym(libcorkscrew, "unwind_backtrace_signal_arch");
t_acquire_my_map_info_list acquire_my_map_info_list
= (t_acquire_my_map_info_list)
dlsym(libcorkscrew, "acquire_my_map_info_list");
t_release_my_map_info_list release_my_map_info_list
= (t_release_my_map_info_list)
dlsym(libcorkscrew, "release_my_map_info_list");
if (unwind_backtrace_signal_arch != NULL
&& acquire_my_map_info_list != NULL
&& release_my_map_info_list != NULL) {
map_info_t*const info = acquire_my_map_info_list();
const ssize_t size =
unwind_backtrace_signal_arch(si, sc, info, frames, ignore_depth,
max_depth);
release_my_map_info_list(info);
return size;
} else {
DEBUG(print("symbols not founs in libcorkscrew.so\n"));
}
dlclose(libcorkscrew);
} else {
DEBUG(print("libcorkscrew.so could not be loaded\n"));
}
return -1;
}
void get_backtrace_symbols(const backtrace_frame_t* backtrace, size_t frames,
backtrace_symbol_t* backtrace_symbols) {
map_info_t* milist = acquire_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;
if (mi->name[0]) {
symbol->map_name = strdup(mi->name);
}
Dl_info info;
if (dladdr((const void*)frame->absolute_pc, &info) && info.dli_sname) {
symbol->relative_symbol_addr = (uintptr_t)info.dli_saddr
- (uintptr_t)info.dli_fbase;
symbol->symbol_name = strdup(info.dli_sname);
symbol->demangled_name = demangle_symbol_name(symbol->symbol_name);
}
}
}
release_my_map_info_list(milist);
}
ssize_t unwind_backtrace(backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
ALOGV("Unwinding current thread %d.", gettid());
map_info_t* milist = acquire_my_map_info_list();
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;
init_memory(&state.memory, milist);
_Unwind_Reason_Code rc = _Unwind_Backtrace(unwind_backtrace_callback, &state);
release_my_map_info_list(milist);
if (state.returned_frames) {
return state.returned_frames;
}
return rc == _URC_END_OF_STACK ? 0 : -1;
}
ssize_t unwind_backtrace_thread(pid_t tid, backtrace_frame_t* backtrace,
size_t ignore_depth, size_t max_depth) {
if (tid == gettid()) {
return unwind_backtrace(backtrace, ignore_depth + 1, max_depth);
}
ALOGV("Unwinding thread %d from thread %d.", tid, gettid());
// TODO: there's no tgkill(2) on Mac OS, so we'd either need the
// mach_port_t or the pthread_t rather than the tid.
#if defined(CORKSCREW_HAVE_ARCH) && !defined(__APPLE__)
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 | SA_ONSTACK;
sigemptyset(&act.sa_mask);
pthread_mutex_lock(&g_unwind_signal_mutex);
map_info_t* milist = acquire_my_map_info_list();
ssize_t frames = -1;
if (!sigaction(SIGURG, &act, &oact)) {
g_unwind_signal_state.map_info_list = milist;
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;
android_atomic_release_store(tid, &g_unwind_signal_state.tid_state);
// Signal the specific thread that we want to dump.
int32_t tid_state = tid;
if (tgkill(getpid(), tid, SIGURG)) {
ALOGV("Failed to send SIGURG to thread %d.", tid);
} else {
// Wait for the other thread to start dumping the stack, or time out.
int wait_millis = 250;
for (;;) {
tid_state = android_atomic_acquire_load(&g_unwind_signal_state.tid_state);
if (tid_state != tid) {
break;
}
if (wait_millis--) {
ALOGV("Waiting for thread %d to start dumping the stack...", tid);
usleep(1000);
} else {
ALOGV("Timed out waiting for thread %d to start dumping the stack.", tid);
break;
}
}
}
// Try to cancel the dump if it has not started yet.
if (tid_state == tid) {
if (!android_atomic_acquire_cas(tid, STATE_CANCEL, &g_unwind_signal_state.tid_state)) {
ALOGV("Canceled thread %d stack dump.", tid);
tid_state = STATE_CANCEL;
} else {
tid_state = android_atomic_acquire_load(&g_unwind_signal_state.tid_state);
}
}
// Wait indefinitely for the dump to finish or be canceled.
// We cannot apply a timeout here because the other thread is accessing state that
// is owned by this thread, such as milist. It should not take very
// long to take the dump once started.
while (tid_state == STATE_DUMPING) {
ALOGV("Waiting for thread %d to finish dumping the stack...", tid);
usleep(1000);
tid_state = android_atomic_acquire_load(&g_unwind_signal_state.tid_state);
}
if (tid_state == STATE_DONE) {
frames = g_unwind_signal_state.returned_frames;
}
sigaction(SIGURG, &oact, NULL);
}
release_my_map_info_list(milist);
pthread_mutex_unlock(&g_unwind_signal_mutex);
return frames;
#else
return -1;
#endif
}
static char *
mono_extension_handle_native_sigsegv_libcorkscrew (void *ctx, MONO_SIG_HANDLER_INFO_TYPE *info)
{
#if defined (__arm__) || defined (__i386__)
char *dl_err;
get_backtrace_symbols_t get_backtrace_symbols;
free_backtrace_symbols_t free_backtrace_symbols;
unwind_backtrace_signal_arch_t unwind_backtrace_signal_arch;
acquire_my_map_info_list_t acquire_my_map_info_list;
release_my_map_info_list_t release_my_map_info_list;
backtrace_frame_t frames [FRAMES_TO_UNWIND];
backtrace_symbol_t symbols [FRAMES_TO_UNWIND];
map_info_t *map_info;
ssize_t frames_unwound;
size_t i;
MonoDl *dl = mono_dl_open ("libcorkscrew.so", MONO_DL_LAZY, &dl_err);
if (!dl)
return dl_err;
LOAD_SYM (dl, dl_err, get_backtrace_symbols, get_backtrace_symbols);
LOAD_SYM (dl, dl_err, free_backtrace_symbols, free_backtrace_symbols);
LOAD_SYM (dl, dl_err, unwind_backtrace_signal_arch, unwind_backtrace_signal_arch);
LOAD_SYM (dl, dl_err, acquire_my_map_info_list, acquire_my_map_info_list);
LOAD_SYM (dl, dl_err, release_my_map_info_list, release_my_map_info_list);
map_info = acquire_my_map_info_list ();
frames_unwound = unwind_backtrace_signal_arch (info, ctx, map_info, frames, 0, FRAMES_TO_UNWIND);
release_my_map_info_list (map_info);
if (frames_unwound == -1) {
mono_dl_close (dl);
return g_strdup ("unwind_backtrace_signal_arch () returned -1");
}
get_backtrace_symbols (frames, frames_unwound, symbols);
for (i = 0; i < frames_unwound; i++) {
backtrace_frame_t *frame = frames + i;
backtrace_symbol_t *symbol = symbols + i;
const char *name = symbol->demangled_name ? symbol->demangled_name : (symbol->symbol_name ? symbol->symbol_name : "???");
uintptr_t off = symbol->relative_pc - symbol->relative_symbol_addr;
uintptr_t ip = frame->absolute_pc;
mono_runtime_printf_err (" at %s+%zu [0x%zx]", name, off, ip);
}
free_backtrace_symbols (symbols, frames_unwound);
mono_dl_close (dl);
return NULL;
#else
return g_strdup ("libcorkscrew is only supported on 32-bit ARM/x86");
#endif
}
