2 * mini-posix.c: POSIX signal handling support for Mono.
5 * Mono Team (mono-list@lists.ximian.com)
7 * Copyright 2001-2003 Ximian, Inc.
8 * Copyright 2003-2008 Ximian, Inc.
9 * Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
11 * See LICENSE for licensing information.
12 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
23 #ifdef HAVE_SYS_TIME_H
26 #ifdef HAVE_SYS_SYSCALL_H
27 #include <sys/syscall.h>
32 #include <mono/metadata/assembly.h>
33 #include <mono/metadata/loader.h>
34 #include <mono/metadata/tabledefs.h>
35 #include <mono/metadata/class.h>
36 #include <mono/metadata/object.h>
37 #include <mono/metadata/tokentype.h>
38 #include <mono/metadata/tabledefs.h>
39 #include <mono/metadata/threads.h>
40 #include <mono/metadata/appdomain.h>
41 #include <mono/metadata/debug-helpers.h>
42 #include <mono/io-layer/io-layer.h>
43 #include "mono/metadata/profiler.h"
44 #include <mono/metadata/profiler-private.h>
45 #include <mono/metadata/mono-config.h>
46 #include <mono/metadata/environment.h>
47 #include <mono/metadata/mono-debug.h>
48 #include <mono/metadata/gc-internals.h>
49 #include <mono/metadata/threads-types.h>
50 #include <mono/metadata/verify.h>
51 #include <mono/metadata/verify-internals.h>
52 #include <mono/metadata/mempool-internals.h>
53 #include <mono/metadata/attach.h>
54 #include <mono/utils/mono-math.h>
55 #include <mono/utils/mono-compiler.h>
56 #include <mono/utils/mono-counters.h>
57 #include <mono/utils/mono-logger-internals.h>
58 #include <mono/utils/mono-mmap.h>
59 #include <mono/utils/dtrace.h>
60 #include <mono/utils/mono-signal-handler.h>
61 #include <mono/utils/mono-threads.h>
62 #include <mono/utils/mono-threads-posix-signals.h>
69 #include "debugger-agent.h"
71 #include "jit-icalls.h"
73 #ifdef PLATFORM_MACOSX
74 #include <mach/mach.h>
75 #include <mach/mach_time.h>
76 #include <mach/clock.h>
79 #if defined(__native_client__) || defined(HOST_WATCHOS)
82 mono_runtime_setup_stat_profiler (void)
84 printf("WARNING: mono_runtime_setup_stat_profiler() called!\n");
89 mono_runtime_shutdown_stat_profiler (void)
95 MONO_SIG_HANDLER_SIGNATURE (mono_chain_signal)
100 #ifndef PLATFORM_MACOSX
102 mono_runtime_install_handlers (void)
108 mono_runtime_posix_install_handlers(void)
114 mono_runtime_shutdown_handlers (void)
119 mono_runtime_cleanup_handlers (void)
123 #if !defined(PLATFORM_MACOSX)
125 mono_runtime_syscall_fork (void)
127 g_assert_not_reached();
132 mono_gdb_render_native_backtraces (pid_t crashed_pid)
139 static GHashTable *mono_saved_signal_handlers = NULL;
141 static struct sigaction *
142 get_saved_signal_handler (int signo)
144 if (mono_saved_signal_handlers)
145 /* The hash is only modified during startup, so no need for locking */
146 return (struct sigaction *)g_hash_table_lookup (mono_saved_signal_handlers, GINT_TO_POINTER (signo));
151 save_old_signal_handler (int signo, struct sigaction *old_action)
153 struct sigaction *handler_to_save = (struct sigaction *)g_malloc (sizeof (struct sigaction));
155 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_CONFIG,
156 "Saving old signal handler for signal %d.", signo);
158 if (! (old_action->sa_flags & SA_SIGINFO)) {
159 handler_to_save->sa_handler = old_action->sa_handler;
161 #ifdef MONO_ARCH_USE_SIGACTION
162 handler_to_save->sa_sigaction = old_action->sa_sigaction;
163 #endif /* MONO_ARCH_USE_SIGACTION */
165 handler_to_save->sa_mask = old_action->sa_mask;
166 handler_to_save->sa_flags = old_action->sa_flags;
168 if (!mono_saved_signal_handlers)
169 mono_saved_signal_handlers = g_hash_table_new (NULL, NULL);
170 g_hash_table_insert (mono_saved_signal_handlers, GINT_TO_POINTER (signo), handler_to_save);
174 free_saved_sig_handler_func (gpointer key, gpointer value, gpointer user_data)
180 free_saved_signal_handlers (void)
182 if (mono_saved_signal_handlers) {
183 g_hash_table_foreach (mono_saved_signal_handlers, free_saved_sig_handler_func, NULL);
184 g_hash_table_destroy (mono_saved_signal_handlers);
185 mono_saved_signal_handlers = NULL;
192 * Call the original signal handler for the signal given by the arguments, which
193 * should be the same as for a signal handler. Returns TRUE if the original handler
194 * was called, false otherwise.
197 MONO_SIG_HANDLER_SIGNATURE (mono_chain_signal)
199 int signal = MONO_SIG_HANDLER_GET_SIGNO ();
200 struct sigaction *saved_handler = (struct sigaction *)get_saved_signal_handler (signal);
202 if (saved_handler && saved_handler->sa_handler) {
203 if (!(saved_handler->sa_flags & SA_SIGINFO)) {
204 saved_handler->sa_handler (signal);
206 #ifdef MONO_ARCH_USE_SIGACTION
207 saved_handler->sa_sigaction (MONO_SIG_HANDLER_PARAMS);
208 #endif /* MONO_ARCH_USE_SIGACTION */
215 MONO_SIG_HANDLER_FUNC (static, sigabrt_signal_handler)
217 MonoJitInfo *ji = NULL;
218 MONO_SIG_HANDLER_INFO_TYPE *info = MONO_SIG_HANDLER_GET_INFO ();
219 MONO_SIG_HANDLER_GET_CONTEXT;
221 if (mono_thread_internal_current ())
222 ji = mono_jit_info_table_find_internal (mono_domain_get (), (char *)mono_arch_ip_from_context (ctx), TRUE, TRUE);
224 if (mono_chain_signal (MONO_SIG_HANDLER_PARAMS))
226 mono_handle_native_sigsegv (SIGABRT, ctx, info);
230 #if defined(__i386__) || defined(__x86_64__)
231 #define FULL_STAT_PROFILER_BACKTRACE 1
232 #define CURRENT_FRAME_GET_BASE_POINTER(f) (* (gpointer*)(f))
233 #define CURRENT_FRAME_GET_RETURN_ADDRESS(f) (* (((gpointer*)(f)) + 1))
234 #if MONO_ARCH_STACK_GROWS_UP
235 #define IS_BEFORE_ON_STACK <
236 #define IS_AFTER_ON_STACK >
238 #define IS_BEFORE_ON_STACK >
239 #define IS_AFTER_ON_STACK <
242 #define FULL_STAT_PROFILER_BACKTRACE 0
245 #if (defined (USE_POSIX_BACKEND) && defined (SIGRTMIN)) || defined (SIGPROF)
246 #define HAVE_PROFILER_SIGNAL
249 #ifdef HAVE_PROFILER_SIGNAL
252 per_thread_profiler_hit (void *ctx)
254 int call_chain_depth = mono_profiler_stat_get_call_chain_depth ();
255 MonoProfilerCallChainStrategy call_chain_strategy = mono_profiler_stat_get_call_chain_strategy ();
257 if (call_chain_depth == 0) {
258 mono_profiler_stat_hit ((guchar *)mono_arch_ip_from_context (ctx), ctx);
260 MonoJitTlsData *jit_tls = (MonoJitTlsData *)mono_native_tls_get_value (mono_jit_tls_id);
261 int current_frame_index = 1;
262 MonoContext mono_context;
263 guchar *ips [call_chain_depth + 1];
265 mono_sigctx_to_monoctx (ctx, &mono_context);
266 ips [0] = (guchar *)MONO_CONTEXT_GET_IP (&mono_context);
268 if (jit_tls != NULL) {
269 if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_NATIVE) {
270 #if FULL_STAT_PROFILER_BACKTRACE
271 guchar *current_frame;
272 guchar *stack_bottom;
275 stack_bottom = (guchar *)jit_tls->end_of_stack;
276 stack_top = (guchar *)MONO_CONTEXT_GET_SP (&mono_context);
277 current_frame = (guchar *)MONO_CONTEXT_GET_BP (&mono_context);
279 while ((current_frame_index <= call_chain_depth) &&
280 (stack_bottom IS_BEFORE_ON_STACK (guchar*) current_frame) &&
281 ((guchar*) current_frame IS_BEFORE_ON_STACK stack_top)) {
282 ips [current_frame_index] = (guchar *)CURRENT_FRAME_GET_RETURN_ADDRESS (current_frame);
283 current_frame_index ++;
284 stack_top = current_frame;
285 current_frame = (guchar *)CURRENT_FRAME_GET_BASE_POINTER (current_frame);
288 call_chain_strategy = MONO_PROFILER_CALL_CHAIN_GLIBC;
292 if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_GLIBC) {
293 #if GLIBC_PROFILER_BACKTRACE
294 current_frame_index = backtrace ((void**) & ips [1], call_chain_depth);
296 call_chain_strategy = MONO_PROFILER_CALL_CHAIN_MANAGED;
300 if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_MANAGED) {
301 MonoDomain *domain = mono_domain_get ();
302 if (domain != NULL) {
306 MonoContext new_mono_context;
308 ji = mono_find_jit_info (domain, jit_tls, &res, NULL, &mono_context,
309 &new_mono_context, NULL, &lmf, &native_offset, NULL);
310 while ((ji != NULL) && (current_frame_index <= call_chain_depth)) {
311 ips [current_frame_index] = (guchar *)MONO_CONTEXT_GET_IP (&new_mono_context);
312 current_frame_index ++;
313 mono_context = new_mono_context;
314 ji = mono_find_jit_info (domain, jit_tls, &res, NULL, &mono_context,
315 &new_mono_context, NULL, &lmf, &native_offset, NULL);
321 mono_profiler_stat_call_chain (current_frame_index, & ips [0], ctx);
325 static MonoNativeThreadId sampling_thread;
327 static gint32 profiler_signals_sent;
328 static gint32 profiler_signals_received;
329 static gint32 profiler_signals_accepted;
330 static gint32 profiler_interrupt_signals_received;
332 MONO_SIG_HANDLER_FUNC (static, profiler_signal_handler)
334 int old_errno = errno;
336 MONO_SIG_HANDLER_GET_CONTEXT;
338 /* See the comment in mono_runtime_shutdown_stat_profiler (). */
339 if (mono_native_thread_id_get () == sampling_thread) {
340 #ifdef HAVE_CLOCK_NANOSLEEP
341 if (mono_profiler_get_sampling_mode () == MONO_PROFILER_STAT_MODE_PROCESS) {
342 InterlockedIncrement (&profiler_interrupt_signals_received);
347 g_error ("%s: Unexpected profiler signal received by the sampler thread", __func__);
350 InterlockedIncrement (&profiler_signals_received);
352 if (mono_thread_info_get_small_id () == -1)
353 return; //an non-attached thread got the signal
355 if (!mono_domain_get () || !mono_native_tls_get_value (mono_jit_tls_id))
356 return; //thread in the process of dettaching
358 InterlockedIncrement (&profiler_signals_accepted);
360 hp_save_index = mono_hazard_pointer_save_for_signal_handler ();
362 mono_thread_info_set_is_async_context (TRUE);
363 per_thread_profiler_hit (ctx);
364 mono_thread_info_set_is_async_context (FALSE);
366 mono_hazard_pointer_restore_for_signal_handler (hp_save_index);
369 mono_chain_signal (MONO_SIG_HANDLER_PARAMS);
374 MONO_SIG_HANDLER_FUNC (static, sigquit_signal_handler)
378 /* We use this signal to start the attach agent too */
379 res = mono_attach_start ();
383 mono_threads_request_thread_dump ();
385 mono_chain_signal (MONO_SIG_HANDLER_PARAMS);
388 MONO_SIG_HANDLER_FUNC (static, sigusr2_signal_handler)
390 gboolean enabled = mono_trace_is_enabled ();
392 mono_trace_enable (!enabled);
394 mono_chain_signal (MONO_SIG_HANDLER_PARAMS);
398 add_signal_handler (int signo, gpointer handler, int flags)
401 struct sigaction previous_sa;
403 #ifdef MONO_ARCH_USE_SIGACTION
404 sa.sa_sigaction = (void (*)(int, siginfo_t *, void *))handler;
405 sigemptyset (&sa.sa_mask);
406 sa.sa_flags = SA_SIGINFO | flags;
407 #ifdef MONO_ARCH_SIGSEGV_ON_ALTSTACK
409 /*Apple likes to deliver SIGBUS for *0 */
410 #ifdef PLATFORM_MACOSX
411 if (signo == SIGSEGV || signo == SIGBUS) {
413 if (signo == SIGSEGV) {
415 sa.sa_flags |= SA_ONSTACK;
418 * libgc will crash when trying to do stack marking for threads which are on
419 * an altstack, so delay the suspend signal after the signal handler has
422 if (mono_gc_get_suspend_signal () != -1)
423 sigaddset (&sa.sa_mask, mono_gc_get_suspend_signal ());
426 if (signo == SIGSEGV) {
428 * Delay abort signals while handling SIGSEGVs since they could go unnoticed.
432 sigemptyset (&block_mask);
435 sa.sa_handler = handler;
436 sigemptyset (&sa.sa_mask);
439 g_assert (sigaction (signo, &sa, &previous_sa) != -1);
441 /* if there was already a handler in place for this signal, store it */
442 if (! (previous_sa.sa_flags & SA_SIGINFO) &&
443 (SIG_DFL == previous_sa.sa_handler)) {
444 /* it there is no sa_sigaction function and the sa_handler is default, we can safely ignore this */
446 if (mono_do_signal_chaining)
447 save_old_signal_handler (signo, &previous_sa);
452 remove_signal_handler (int signo)
455 struct sigaction *saved_action = get_saved_signal_handler (signo);
458 sa.sa_handler = SIG_DFL;
459 sigemptyset (&sa.sa_mask);
462 sigaction (signo, &sa, NULL);
464 g_assert (sigaction (signo, saved_action, NULL) != -1);
469 mono_runtime_posix_install_handlers (void)
474 if (mini_get_debug_options ()->handle_sigint)
475 add_signal_handler (SIGINT, mono_sigint_signal_handler, SA_RESTART);
477 add_signal_handler (SIGFPE, mono_sigfpe_signal_handler, 0);
478 add_signal_handler (SIGQUIT, sigquit_signal_handler, SA_RESTART);
479 add_signal_handler (SIGILL, mono_sigill_signal_handler, 0);
480 add_signal_handler (SIGBUS, mono_sigsegv_signal_handler, 0);
481 if (mono_jit_trace_calls != NULL)
482 add_signal_handler (SIGUSR2, sigusr2_signal_handler, SA_RESTART);
484 /* it seems to have become a common bug for some programs that run as parents
485 * of many processes to block signal delivery for real time signals.
486 * We try to detect and work around their breakage here.
488 sigemptyset (&signal_set);
489 if (mono_gc_get_suspend_signal () != -1)
490 sigaddset (&signal_set, mono_gc_get_suspend_signal ());
491 if (mono_gc_get_restart_signal () != -1)
492 sigaddset (&signal_set, mono_gc_get_restart_signal ());
493 sigaddset (&signal_set, SIGCHLD);
494 sigprocmask (SIG_UNBLOCK, &signal_set, NULL);
496 signal (SIGPIPE, SIG_IGN);
498 add_signal_handler (SIGABRT, sigabrt_signal_handler, 0);
501 add_signal_handler (SIGSEGV, mono_sigsegv_signal_handler, 0);
504 #ifndef PLATFORM_MACOSX
506 mono_runtime_install_handlers (void)
508 mono_runtime_posix_install_handlers ();
513 mono_runtime_cleanup_handlers (void)
515 if (mini_get_debug_options ()->handle_sigint)
516 remove_signal_handler (SIGINT);
518 remove_signal_handler (SIGFPE);
519 remove_signal_handler (SIGQUIT);
520 remove_signal_handler (SIGILL);
521 remove_signal_handler (SIGBUS);
522 if (mono_jit_trace_calls != NULL)
523 remove_signal_handler (SIGUSR2);
525 remove_signal_handler (SIGABRT);
527 remove_signal_handler (SIGSEGV);
529 free_saved_signal_handlers ();
532 #ifdef HAVE_PROFILER_SIGNAL
534 static volatile gint32 sampling_thread_running;
536 #ifdef PLATFORM_MACOSX
538 static clock_serv_t sampling_clock_service;
546 ret = host_get_clock_service (mach_host_self (), SYSTEM_CLOCK, &sampling_clock_service);
547 } while (ret == KERN_ABORTED);
549 if (ret != KERN_SUCCESS)
550 g_error ("%s: host_get_clock_service () returned %d", __func__, ret);
559 ret = mach_port_deallocate (mach_task_self (), sampling_clock_service);
560 } while (ret == KERN_ABORTED);
562 if (ret != KERN_SUCCESS)
563 g_error ("%s: mach_port_deallocate () returned %d", __func__, ret);
567 clock_get_time_ns (void)
570 mach_timespec_t mach_ts;
573 ret = clock_get_time (sampling_clock_service, &mach_ts);
574 } while (ret == KERN_ABORTED);
576 if (ret != KERN_SUCCESS)
577 g_error ("%s: clock_get_time () returned %d", __func__, ret);
579 return ((guint64) mach_ts.tv_sec * 1000000000) + (guint64) mach_ts.tv_nsec;
583 clock_sleep_ns_abs (guint64 ns_abs)
586 mach_timespec_t then, remain_unused;
588 then.tv_sec = ns_abs / 1000000000;
589 then.tv_nsec = ns_abs % 1000000000;
592 ret = clock_sleep (sampling_clock_service, TIME_ABSOLUTE, then, &remain_unused);
594 if (ret != KERN_SUCCESS && ret != KERN_ABORTED)
595 g_error ("%s: clock_sleep () returned %d", __func__, ret);
596 } while (ret == KERN_ABORTED && InterlockedRead (&sampling_thread_running));
601 clockid_t sampling_posix_clock;
606 switch (mono_profiler_get_sampling_mode ()) {
607 case MONO_PROFILER_STAT_MODE_PROCESS:
608 #ifdef HAVE_CLOCK_NANOSLEEP
610 * If we don't have clock_nanosleep (), measuring the process time
611 * makes very little sense as we can only use nanosleep () to sleep on
614 sampling_posix_clock = CLOCK_PROCESS_CPUTIME_ID;
617 case MONO_PROFILER_STAT_MODE_REAL: sampling_posix_clock = CLOCK_MONOTONIC; break;
618 default: g_assert_not_reached (); break;
628 clock_get_time_ns (void)
632 if (clock_gettime (sampling_posix_clock, &ts) == -1)
633 g_error ("%s: clock_gettime () returned -1, errno = %d", __func__, errno);
635 return ((guint64) ts.tv_sec * 1000000000) + (guint64) ts.tv_nsec;
639 clock_sleep_ns_abs (guint64 ns_abs)
641 #ifdef HAVE_CLOCK_NANOSLEEP
643 struct timespec then;
645 then.tv_sec = ns_abs / 1000000000;
646 then.tv_nsec = ns_abs % 1000000000;
649 ret = clock_nanosleep (sampling_posix_clock, TIMER_ABSTIME, &then, NULL);
651 if (ret != 0 && ret != EINTR)
652 g_error ("%s: clock_nanosleep () returned %d", __func__, ret);
653 } while (ret == EINTR && InterlockedRead (&sampling_thread_running));
660 * What follows is a crude attempt at emulating clock_nanosleep () on OSs
661 * which don't provide it (e.g. FreeBSD).
663 * The problem with nanosleep () is that if it is interrupted by a signal,
664 * time will drift as a result of having to restart the call after the
665 * signal handler has finished. For this reason, we avoid using the rem
666 * argument of nanosleep (). Instead, before every nanosleep () call, we
667 * check if enough time has passed to satisfy the sleep request. If yes, we
668 * simply return. If not, we calculate the difference and do another sleep.
670 * This should reduce the amount of drift that happens because we account
671 * for the time spent executing the signal handler, which nanosleep () is
672 * not guaranteed to do for the rem argument.
674 * The downside to this approach is that it is slightly expensive: We have
675 * to make an extra system call to retrieve the current time whenever we're
676 * going to restart a nanosleep () call. This is unlikely to be a problem
677 * in practice since the sampling thread won't be receiving many signals in
678 * the first place (it's a tools thread, so no STW), and because typical
679 * sleep periods for the thread are many orders of magnitude bigger than
680 * the time it takes to actually perform that system call (just a few
684 diff = (gint64) ns_abs - (gint64) clock_get_time_ns ();
689 req.tv_sec = diff / 1000000000;
690 req.tv_nsec = diff % 1000000000;
692 if ((ret = nanosleep (&req, NULL)) == -1 && errno != EINTR)
693 g_error ("%s: nanosleep () returned -1, errno = %d", __func__, errno);
694 } while (ret == -1 && InterlockedRead (&sampling_thread_running));
700 static int profiler_signal;
701 static volatile gint32 sampling_thread_exiting;
703 static mono_native_thread_return_t
704 sampling_thread_func (void *data)
706 mono_threads_attach_tools_thread ();
707 mono_thread_info_set_name (mono_native_thread_id_get (), "Profiler sampler");
709 gint64 rate = 1000000000 / mono_profiler_get_sampling_rate ();
712 struct sched_param old_sched;
713 pthread_getschedparam (pthread_self (), &old_policy, &old_sched);
716 * Attempt to switch the thread to real time scheduling. This will not
717 * necessarily work on all OSs; for example, most Linux systems will give
718 * us EPERM here unless configured to allow this.
720 * TODO: This does not work on Mac (and maybe some other OSs). On Mac, we
721 * have to use the Mach thread policy routines to switch to real-time
722 * scheduling. This is quite tricky as we need to specify how often we'll
723 * be doing work (easy), the normal processing time needed (also easy),
724 * and the maximum amount of processing time needed (hard). This is
725 * further complicated by the fact that if we misbehave and take too long
726 * to do our work, the kernel may knock us back down to the normal thread
727 * scheduling policy without telling us.
729 struct sched_param sched = { .sched_priority = sched_get_priority_max (SCHED_FIFO) };
730 pthread_setschedparam (pthread_self (), SCHED_FIFO, &sched);
734 guint64 sleep = clock_get_time_ns ();
736 while (InterlockedRead (&sampling_thread_running)) {
739 FOREACH_THREAD_SAFE (info) {
740 /* info should never be this thread as we're a tools thread. */
741 g_assert (mono_thread_info_get_tid (info) != mono_native_thread_id_get ());
743 mono_threads_pthread_kill (info, profiler_signal);
744 InterlockedIncrement (&profiler_signals_sent);
745 } FOREACH_THREAD_SAFE_END
747 clock_sleep_ns_abs (sleep);
750 InterlockedWrite (&sampling_thread_exiting, 1);
754 pthread_setschedparam (pthread_self (), old_policy, &old_sched);
756 mono_thread_info_detach ();
762 mono_runtime_shutdown_stat_profiler (void)
764 InterlockedWrite (&sampling_thread_running, 0);
766 #ifdef HAVE_CLOCK_NANOSLEEP
768 * There is a slight problem when we're using CLOCK_PROCESS_CPUTIME_ID: If
769 * we're shutting down and there's largely no activity in the process other
770 * than waiting for the sampler thread to shut down, it can take upwards of
771 * 20 seconds (depending on a lot of factors) for us to shut down because
772 * the sleep progresses very slowly as a result of the low CPU activity.
774 * We fix this by repeatedly sending the profiler signal to the sampler
775 * thread in order to interrupt the sleep. clock_sleep_ns_abs () will check
776 * sampling_thread_running upon an interrupt and return immediately if it's
777 * zero. profiler_signal_handler () has a special case to ignore the signal
778 * for the sampler thread.
780 * We do not need to do this on platforms where we use a regular sleep
781 * based on a monotonic clock. The sleep will return in a reasonable amount
782 * of time in those cases.
784 if (mono_profiler_get_sampling_mode () == MONO_PROFILER_STAT_MODE_PROCESS) {
785 MonoThreadInfo *info;
787 // Did it shut down already?
788 if ((info = mono_thread_info_lookup (sampling_thread))) {
789 while (!InterlockedRead (&sampling_thread_exiting)) {
790 mono_threads_pthread_kill (info, profiler_signal);
791 mono_thread_info_usleep (10 * 1000 /* 10ms */);
794 // Make sure info can be freed.
795 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
800 pthread_join (sampling_thread, NULL);
803 * We can't safely remove the signal handler because we have no guarantee
804 * that all pending signals have been delivered at this point. This should
805 * not really be a problem anyway.
807 //remove_signal_handler (profiler_signal);
811 mono_runtime_setup_stat_profiler (void)
814 * Use a real-time signal when possible. This gives us roughly a 99% signal
815 * delivery rate in all cases. On the other hand, using a regular signal
816 * tends to result in awful delivery rates when the application is heavily
819 * We avoid real-time signals on Android as they're super broken in certain
820 * API levels (too small sigset_t, nonsensical SIGRTMIN/SIGRTMAX values,
823 * TODO: On Mac, we should explore using the Mach thread suspend/resume
824 * functions and doing the stack walk from the sampling thread. This would
825 * get us a 100% sampling rate. However, this may interfere with the GC's
826 * STW logic. Could perhaps be solved by taking the suspend lock.
828 #if defined (USE_POSIX_BACKEND) && defined (SIGRTMIN) && !defined (PLATFORM_ANDROID)
829 /* Just take the first real-time signal we can get. */
830 profiler_signal = mono_threads_posix_signal_search_alternative (-1);
832 profiler_signal = SIGPROF;
835 add_signal_handler (profiler_signal, profiler_signal_handler, SA_RESTART);
837 mono_counters_register ("Sampling signals sent", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_signals_sent);
838 mono_counters_register ("Sampling signals received", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_signals_received);
839 mono_counters_register ("Sampling signals accepted", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_signals_accepted);
840 mono_counters_register ("Shutdown signals received", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_interrupt_signals_received);
842 InterlockedWrite (&sampling_thread_running, 1);
843 mono_native_thread_create (&sampling_thread, sampling_thread_func, NULL);
849 mono_runtime_shutdown_stat_profiler (void)
854 mono_runtime_setup_stat_profiler (void)
860 #if !defined(PLATFORM_MACOSX)
862 mono_runtime_syscall_fork ()
864 #if defined(PLATFORM_ANDROID)
865 /* SYS_fork is defined to be __NR_fork which is not defined in some ndk versions */
866 g_assert_not_reached ();
868 #elif defined(SYS_fork)
869 return (pid_t) syscall (SYS_fork);
871 g_assert_not_reached ();
877 mono_gdb_render_native_backtraces (pid_t crashed_pid)
879 const char *argv [9];
880 char template_ [] = "/tmp/mono-lldb-commands.XXXXXX";
883 gboolean using_lldb = FALSE;
885 argv [0] = g_find_program_in_path ("gdb");
886 if (argv [0] == NULL) {
887 argv [0] = g_find_program_in_path ("lldb");
891 if (argv [0] == NULL)
895 if (mkstemp (template_) == -1)
898 commands = fopen (template_, "w");
900 fprintf (commands, "process attach --pid %ld\n", (long) crashed_pid);
901 fprintf (commands, "thread list\n");
902 fprintf (commands, "thread backtrace all\n");
903 fprintf (commands, "detach\n");
904 fprintf (commands, "quit\n");
909 argv [1] = "--source";
910 argv [2] = template_;
914 sprintf (buf1, "attach %ld", (long) crashed_pid);
917 argv [4] = "info threads";
919 argv [6] = "thread apply all bt";
920 argv [7] = "--batch";
924 execv (argv [0], (char**)argv);
930 #endif /* __native_client__ */
932 #if !defined (__MACH__)
935 mono_thread_state_init_from_handle (MonoThreadUnwindState *tctx, MonoThreadInfo *info)
937 g_error ("Posix systems don't support mono_thread_state_init_from_handle");