/* Internal signal pass-through. Allows to peek the "real" crash before
* calling the Java handler. Remember than Java needs many of the signals
* (for the JIT, for test-free NullPointerException handling, etc.)
* We record the siginfo_t context in this function each time it is being
* called, to be able to know what error caused an issue.
*/
static void coffeecatch_signal_pass(const int code, siginfo_t *const si,
void *const sc) {
native_code_handler_struct *t;
DEBUG(print("caught signal\n"));
/* Call the "real" Java handler for JIT and internals. */
coffeecatch_call_old_signal_handler(code, si, sc);
/* Still here ?
* FIXME TODO: This is the Dalvik behavior - but is it the SunJVM one ? */
/* Ensure we do not deadlock. Default of ALRM is to die.
* (signal() and alarm() are signal-safe) */
signal(code, SIG_DFL);
coffeecatch_start_alarm();
/* Available context ? */
t = coffeecatch_get();
if (t != NULL) {
/* An alarm() call was triggered. */
coffeecatch_mark_alarm(t);
/* Take note of the signal. */
coffeecatch_copy_context(t, code, si, sc);
/* Back to the future. */
coffeecatch_try_jump_userland(t, code, si, sc);
}
/* Nope. (abort() is signal-safe) */
DEBUG(print("calling abort()\n"));
signal(SIGABRT, SIG_DFL);
abort();
}
/* Internal crash handler for abort(). Java calls abort() if its signal handler
* could not resolve the signal ; thus calling us through this handler. */
static void coffeecatch_signal_abort(const int code, siginfo_t *const si,
void *const sc) {
native_code_handler_struct *t;
(void) sc; /* UNUSED */
DEBUG(print("caught abort\n"));
/* Ensure we do not deadlock. Default of ALRM is to die.
* (signal() and alarm() are signal-safe) */
signal(code, SIG_DFL);
coffeecatch_start_alarm();
/* Available context ? */
t = coffeecatch_get();
if (t != NULL) {
/* An alarm() call was triggered. */
coffeecatch_mark_alarm(t);
/* Take note (real "abort()") */
coffeecatch_copy_context(t, code, si, sc);
/* Back to the future. */
coffeecatch_try_jump_userland(t, code, si, sc);
}
/* No such restore point, call old signal handler then. */
DEBUG(print("calling old signal handler\n"));
coffeecatch_call_old_signal_handler(code, si, sc);
/* Nope. (abort() is signal-safe) */
DEBUG(print("calling abort()\n"));
abort();
}
/**
* Enumerate backtrace information.
*/
void coffeecatch_get_backtrace_info(void (*fun)(void *arg,
const char *module,
uintptr_t addr,
const char *function,
uintptr_t offset), void *arg) {
const native_code_handler_struct* const t = coffeecatch_get();
if (t != NULL) {
#if (defined(USE_CORKSCREW))
t_coffeecatch_backtrace_symbols_fun bt;
bt.fun = fun;
bt.arg = arg;
coffeecatch_backtrace_symbols(t->frames, t->frames_size,
coffeecatch_backtrace_symbols_fun, &bt);
#elif (defined(USE_UNWIND))
size_t i;
for(i = 0; i < t->frames_size; i++) {
const uintptr_t pc = t->frames[i];
format_pc_address_cb(pc, fun, arg);
}
#else
(void) fun;
(void) arg;
#endif
}
}
/**
* Get the signal associated with the crash.
*/
int coffeecatch_get_signal() {
const native_code_handler_struct* const t = coffeecatch_get();
if (t != NULL) {
return t->code;
} else {
return -1;
}
}
/**
* Returns 1 if we are already inside a coffeecatch block, 0 otherwise.
*/
int coffeecatch_inside() {
native_code_handler_struct *const t = coffeecatch_get();
if (t != NULL && t->reenter > 0) {
t->reenter++;
return 1;
}
return 0;
}
void coffeecatch_abort(const char* exp, const char* file, int line) {
native_code_handler_struct *const t = coffeecatch_get();
if (t != NULL) {
t->expression = exp;
t->file = file;
t->line = line;
}
abort();
}
int coffeecatch_cancel_pending_alarm() {
native_code_handler_struct *const t = coffeecatch_get();
if (t != NULL && t->alarm) {
t->alarm = 0;
/* "If seconds is 0, a pending alarm request, if any, is canceled." */
alarm(0);
return 0;
}
return -1;
}
/**
* Calls coffeecatch_handler_setup(1) to setup a crash handler, mark the
* context as valid, and return 0 upon success.
*/
int coffeecatch_setup() {
if (coffeecatch_handler_setup(1) == 0) {
native_code_handler_struct *const t = coffeecatch_get();
assert(t != NULL);
t->ctx_is_set = 1;
return 0;
} else {
return -1;
}
}
/**
* Calls coffeecatch_handler_cleanup()
*/
void coffeecatch_cleanup() {
native_code_handler_struct *const t = coffeecatch_get();
assert(t != NULL);
assert(t->reenter > 0);
t->reenter--;
if (t->reenter == 0) {
t->ctx_is_set = 0;
coffeecatch_handler_cleanup();
}
}
/**
* Release the resources allocated by a previous call to
* coffeecatch_handler_setup().
* This function must be called as many times as
* coffeecatch_handler_setup() was called to fully release allocated
* resources.
**/
static int coffeecatch_handler_cleanup() {
/* Cleanup locals. */
native_code_handler_struct *const t = coffeecatch_get();
if (t != NULL) {
DEBUG(print("removing thread alternative stack\n"));
/* Erase thread-specific value now (detach). */
if (pthread_setspecific(native_code_thread, NULL) != 0) {
assert(! "pthread_setspecific() failed");
}
/* Free handler and reset slternate stack */
if (coffeecatch_native_code_handler_struct_free(t) != 0) {
return -1;
}
DEBUG(print("removed thread alternative stack\n"));
}
/* Cleanup globals. */
if (pthread_mutex_lock(&native_code_g.mutex) != 0) {
assert(! "pthread_mutex_lock() failed");
}
assert(native_code_g.initialized != 0);
if (--native_code_g.initialized == 0) {
size_t i;
DEBUG(print("removing global signal handlers\n"));
/* Restore signal handler. */
for(i = 0; native_sig_catch[i] != 0; i++) {
const int sig = native_sig_catch[i];
assert(sig < SIG_NUMBER_MAX);
if (sigaction(sig, &native_code_g.sa_old[sig], NULL) != 0) {
return -1;
}
}
/* Free old structure. */
free(native_code_g.sa_old);
native_code_g.sa_old = NULL;
/* Delete thread var. */
if (pthread_key_delete(native_code_thread) != 0) {
assert(! "pthread_key_delete() failed");
}
DEBUG(print("removed global signal handlers\n"));
}
if (pthread_mutex_unlock(&native_code_g.mutex) != 0) {
assert(! "pthread_mutex_unlock() failed");
}
return 0;
}
/**
* Get the backtrace size. Returns 0 if no backtrace is available.
*/
size_t coffeecatch_get_backtrace_size(void) {
#ifdef USE_UNWIND
const native_code_handler_struct* const t = coffeecatch_get();
if (t != NULL) {
return t->frames_size;
} else {
return 0;
}
#else
return 0;
#endif
}
/**
* Acquire the crash handler for the current thread.
* The coffeecatch_handler_cleanup() must be called to release allocated
* resources.
**/
static int coffeecatch_handler_setup(int setup_thread) {
int code;
DEBUG(print("setup for a new handler\n"));
/* Initialize globals. */
if (pthread_mutex_lock(&native_code_g.mutex) != 0) {
return -1;
}
code = coffeecatch_handler_setup_global();
if (pthread_mutex_unlock(&native_code_g.mutex) != 0) {
return -1;
}
/* Global initialization failed. */
if (code != 0) {
return -1;
}
/* Initialize locals. */
if (setup_thread && coffeecatch_get() == NULL) {
native_code_handler_struct *const t =
coffeecatch_native_code_handler_struct_init();
if (t == NULL) {
return -1;
}
DEBUG(print("installing thread alternative stack\n"));
/* Set thread-specific value. */
if (pthread_setspecific(native_code_thread, t) != 0) {
coffeecatch_native_code_handler_struct_free(t);
return -1;
}
DEBUG(print("installed thread alternative stack\n"));
}
/* OK. */
return 0;
}
/**
* Get the <index>th element of the backtrace, or 0 upon error.
*/
uintptr_t coffeecatch_get_backtrace(ssize_t index) {
#ifdef USE_UNWIND
const native_code_handler_struct* const t = coffeecatch_get();
if (t != NULL) {
if (index < 0) {
index = t->frames_size + index;
}
if (index >= 0 && (size_t) index < t->frames_size) {
#ifdef USE_CORKSCREW
return t->frames[index].absolute_pc;
#else
return t->frames[index];
#endif
}
}
#else
(void) index;
#endif
return 0;
}
sigjmp_buf* coffeecatch_get_ctx() {
native_code_handler_struct* t = coffeecatch_get();
assert(t != NULL);
return &t->ctx;
}
/**
* Calls coffeecatch_handler_cleanup()
*/
void coffeecatch_cleanup() {
native_code_handler_struct *const t = coffeecatch_get();
assert(t != NULL);
t->ctx_is_set = 0;
coffeecatch_handler_cleanup();
}
/**
* Get the full error message associated with the crash.
*/
const char* coffeecatch_get_message() {
const int error = errno;
const native_code_handler_struct* const t = coffeecatch_get();
/* Found valid handler. */
if (t != NULL) {
char * const buffer = t->stack_buffer;
const size_t buffer_len = t->stack_buffer_size;
size_t buffer_offs = 0;
const char* const posix_desc =
coffeecatch_desc_sig(t->si.si_signo, t->si.si_code);
/* Assertion failure ? */
if ((t->code == SIGABRT
#ifdef __ANDROID__
/* See Android BUG #16672:
* "C assert() failure causes SIGSEGV when it should cause SIGABRT" */
|| (t->code == SIGSEGV && (uintptr_t) t->si.si_addr == 0xdeadbaad)
#endif
) && t->expression != NULL) {
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs,
"assertion '%s' failed at %s:%d",
t->expression, t->file, t->line);
buffer_offs += strlen(&buffer[buffer_offs]);
}
/* Signal */
else {
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs, "signal %d",
t->si.si_signo);
buffer_offs += strlen(&buffer[buffer_offs]);
/* Description */
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs, " (%s)",
posix_desc);
buffer_offs += strlen(&buffer[buffer_offs]);
/* Address of faulting instruction */
if (t->si.si_signo == SIGILL || t->si.si_signo == SIGSEGV) {
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs, " at address %p",
t->si.si_addr);
buffer_offs += strlen(&buffer[buffer_offs]);
}
}
/* [POSIX] If non-zero, an errno value associated with this signal,
as defined in <errno.h>. */
if (t->si.si_errno != 0) {
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs, ": ");
buffer_offs += strlen(&buffer[buffer_offs]);
if (strerror_r(t->si.si_errno, &buffer[buffer_offs],
buffer_len - buffer_offs) == 0) {
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs,
"unknown error");
buffer_offs += strlen(&buffer[buffer_offs]);
}
}
/* Sending process ID. */
if (t->si.si_signo == SIGCHLD && t->si.si_pid != 0) {
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs,
" (sent by pid %d)", (int) t->si.si_pid);
buffer_offs += strlen(&buffer[buffer_offs]);
}
/* Faulting program counter location. */
if (coffeecatch_get_pc_from_ucontext(&t->uc) != 0) {
const uintptr_t pc = coffeecatch_get_pc_from_ucontext(&t->uc);
snprintf(&buffer[buffer_offs], buffer_len - buffer_offs, " ");
buffer_offs += strlen(&buffer[buffer_offs]);
format_pc_address(&buffer[buffer_offs], buffer_len - buffer_offs, pc);
buffer_offs += strlen(&buffer[buffer_offs]);
}
/* Return string. */
buffer[buffer_offs] = '\0';
return t->stack_buffer;
} else {
/* Static buffer in case of emergency */
static char buffer[256];
#ifdef _GNU_SOURCE
return strerror_r(error, &buffer[0], sizeof(buffer));
#else
const int code = strerror_r(error, &buffer[0], sizeof(buffer));
errno = error;
if (code == 0) {
return buffer;
} else {
return "unknown error during crash handler setup";
}
#endif
}
}
