mono/mini/mini-posix.c

   1 /*
   2  * mini-posix.c: POSIX signal handling support for Mono.
   3  *
   4  * Authors:
   5  *   Mono Team (mono-list@lists.ximian.com)
   6  *
   7  * Copyright 2001-2003 Ximian, Inc.
   8  * Copyright 2003-2008 Ximian, Inc.
   9  * Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
  10  *
  11  * See LICENSE for licensing information.
  12  */
  13 #include <config.h>
  14 #include <signal.h>
  15 #ifdef HAVE_ALLOCA_H
  16 #include <alloca.h>
  17 #endif
  18 #ifdef HAVE_UNISTD_H
  19 #include <unistd.h>
  20 #endif
  21 #include <math.h>
  22 #ifdef HAVE_SYS_TIME_H
  23 #include <sys/time.h>
  24 #endif
  25 #ifdef HAVE_SYS_SYSCALL_H
  26 #include <sys/syscall.h>
  27 #endif
  28
  29 #include <mono/metadata/assembly.h>
  30 #include <mono/metadata/loader.h>
  31 #include <mono/metadata/tabledefs.h>
  32 #include <mono/metadata/class.h>
  33 #include <mono/metadata/object.h>
  34 #include <mono/metadata/tokentype.h>
  35 #include <mono/metadata/tabledefs.h>
  36 #include <mono/metadata/threads.h>
  37 #include <mono/metadata/appdomain.h>
  38 #include <mono/metadata/debug-helpers.h>
  39 #include <mono/io-layer/io-layer.h>
  40 #include "mono/metadata/profiler.h"
  41 #include <mono/metadata/profiler-private.h>
  42 #include <mono/metadata/mono-config.h>
  43 #include <mono/metadata/environment.h>
  44 #include <mono/metadata/mono-debug.h>
  45 #include <mono/metadata/gc-internal.h>
  46 #include <mono/metadata/threads-types.h>
  47 #include <mono/metadata/verify.h>
  48 #include <mono/metadata/verify-internals.h>
  49 #include <mono/metadata/mempool-internals.h>
  50 #include <mono/metadata/attach.h>
  51 #include <mono/utils/mono-math.h>
  52 #include <mono/utils/mono-compiler.h>
  53 #include <mono/utils/mono-counters.h>
  54 #include <mono/utils/mono-logger-internal.h>
  55 #include <mono/utils/mono-mmap.h>
  56 #include <mono/utils/dtrace.h>
  57
  58 #include "mini.h"
  59 #include <string.h>
  60 #include <ctype.h>
  61 #include "trace.h"
  62 #include "version.h"
  63 #include "debugger-agent.h"
  64
  65 #include "jit-icalls.h"
  66
  67 #if defined(__native_client__)
  68
  69 void
  70 mono_runtime_setup_stat_profiler (void)
  71 {
  72         printf("WARNING: mono_runtime_setup_stat_profiler() called!\n");
  73 }
  74
  75
  76 void
  77 mono_runtime_shutdown_stat_profiler (void)
  78 {
  79 }
  80
  81
  82 gboolean
  83 SIG_HANDLER_SIGNATURE (mono_chain_signal)
  84 {
  85         return FALSE;
  86 }
  87
  88 void
  89 mono_runtime_install_handlers (void)
  90 {
  91 }
  92
  93 void
  94 mono_runtime_shutdown_handlers (void)
  95 {
  96 }
  97
  98 void
  99 mono_runtime_cleanup_handlers (void)
 100 {
 101 }
 102
 103
 104
 105 #else
 106
 107 static GHashTable *mono_saved_signal_handlers = NULL;
 108
 109 static gpointer
 110 get_saved_signal_handler (int signo)
 111 {
 112         if (mono_saved_signal_handlers)
 113                 /* The hash is only modified during startup, so no need for locking */
 114                 return g_hash_table_lookup (mono_saved_signal_handlers, GINT_TO_POINTER (signo));
 115         return NULL;
 116 }
 117
 118 static void
 119 save_old_signal_handler (int signo, struct sigaction *old_action)
 120 {
 121         struct sigaction *handler_to_save = g_malloc (sizeof (struct sigaction));
 122
 123         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_CONFIG,
 124                                 "Saving old signal handler for signal %d.", signo);
 125
 126         if (! (old_action->sa_flags & SA_SIGINFO)) {
 127                 handler_to_save->sa_handler = old_action->sa_handler;
 128         } else {
 129 #ifdef MONO_ARCH_USE_SIGACTION
 130                 handler_to_save->sa_sigaction = old_action->sa_sigaction;
 131 #endif /* MONO_ARCH_USE_SIGACTION */
 132         }
 133         handler_to_save->sa_mask = old_action->sa_mask;
 134         handler_to_save->sa_flags = old_action->sa_flags;
 135
 136         if (!mono_saved_signal_handlers)
 137                 mono_saved_signal_handlers = g_hash_table_new (NULL, NULL);
 138         g_hash_table_insert (mono_saved_signal_handlers, GINT_TO_POINTER (signo), handler_to_save);
 139 }
 140
 141 static void
 142 free_saved_sig_handler_func (gpointer key, gpointer value, gpointer user_data)
 143 {
 144         g_free (value);
 145 }
 146
 147 static void
 148 free_saved_signal_handlers (void)
 149 {
 150         if (mono_saved_signal_handlers) {
 151                 g_hash_table_foreach (mono_saved_signal_handlers, free_saved_sig_handler_func, NULL);
 152                 g_hash_table_destroy (mono_saved_signal_handlers);
 153                 mono_saved_signal_handlers = NULL;
 154         }
 155 }
 156
 157 /*
 158  * mono_chain_signal:
 159  *
 160  *   Call the original signal handler for the signal given by the arguments, which
 161  * should be the same as for a signal handler. Returns TRUE if the original handler
 162  * was called, false otherwise.
 163  */
 164 gboolean
 165 SIG_HANDLER_SIGNATURE (mono_chain_signal)
 166 {
 167         int signal = _dummy;
 168         struct sigaction *saved_handler = get_saved_signal_handler (signal);
 169
 170         GET_CONTEXT;
 171
 172         if (saved_handler && saved_handler->sa_handler) {
 173                 if (!(saved_handler->sa_flags & SA_SIGINFO)) {
 174                         saved_handler->sa_handler (signal);
 175                 } else {
 176 #ifdef MONO_ARCH_USE_SIGACTION
 177                         saved_handler->sa_sigaction (signal, info, ctx);
 178 #endif /* MONO_ARCH_USE_SIGACTION */
 179                 }
 180                 return TRUE;
 181         }
 182         return FALSE;
 183 }
 184
 185 static void
 186 SIG_HANDLER_SIGNATURE (sigabrt_signal_handler)
 187 {
 188         MonoJitInfo *ji = NULL;
 189         GET_CONTEXT;
 190
 191         if (mono_thread_internal_current ())
 192                 ji = mono_jit_info_table_find (mono_domain_get (), mono_arch_ip_from_context(ctx));
 193         if (!ji) {
 194         if (mono_chain_signal (SIG_HANDLER_PARAMS))
 195                         return;
 196                 mono_handle_native_sigsegv (SIGABRT, ctx);
 197         }
 198 }
 199
 200 static void
 201 SIG_HANDLER_SIGNATURE (sigusr1_signal_handler)
 202 {
 203         gboolean running_managed;
 204         MonoException *exc;
 205         MonoInternalThread *thread = mono_thread_internal_current ();
 206         MonoDomain *domain = mono_domain_get ();
 207         void *ji;
 208
 209         GET_CONTEXT;
 210
 211         if (!thread || !domain)
 212                 /* The thread might not have started up yet */
 213                 /* FIXME: Specify the synchronization with start_wrapper () in threads.c */
 214                 return;
 215
 216         if (thread->ignore_next_signal) {
 217                 thread->ignore_next_signal = FALSE;
 218                 return;
 219         }
 220
 221         if (thread->thread_dump_requested) {
 222                 thread->thread_dump_requested = FALSE;
 223
 224                 mono_print_thread_dump (ctx);
 225         }
 226
 227         /*
 228          * This is an async signal, so the code below must not call anything which
 229          * is not async safe. That includes the pthread locking functions. If we
 230          * know that we interrupted managed code, then locking is safe.
 231          */
 232         /*
 233          * On OpenBSD, ctx can be NULL if we are interrupting poll ().
 234          */
 235         if (ctx) {
 236                 ji = mono_jit_info_table_find (mono_domain_get (), mono_arch_ip_from_context(ctx));
 237                 running_managed = ji != NULL;
 238
 239                 if (mono_debugger_agent_thread_interrupt (ctx, ji))
 240                         return;
 241         } else {
 242                 running_managed = FALSE;
 243         }
 244
 245         /* We can't do handler block checking from metadata since it requires doing
 246          * a stack walk with context.
 247          *
 248          * FIXME add full-aot support.
 249          */
 250 #ifdef MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX
 251         if (!mono_aot_only && ctx) {
 252                 MonoThreadUnwindState unwind_state;
 253                 if (mono_thread_state_init_from_sigctx (&unwind_state, ctx)) {
 254                         if (mono_install_handler_block_guard (&unwind_state)) {
 255 #ifndef HOST_WIN32
 256                                 /*Clear current thread from been wapi interrupted otherwise things can go south*/
 257                                 wapi_clear_interruption ();
 258 #endif
 259                                 return;
 260                         }
 261                 }
 262         }
 263 #endif
 264
 265         exc = mono_thread_request_interruption (running_managed);
 266         if (!exc)
 267                 return;
 268
 269         mono_arch_handle_exception (ctx, exc);
 270 }
 271
 272 #if defined(__i386__) || defined(__x86_64__)
 273 #define FULL_STAT_PROFILER_BACKTRACE 1
 274 #define CURRENT_FRAME_GET_BASE_POINTER(f) (* (gpointer*)(f))
 275 #define CURRENT_FRAME_GET_RETURN_ADDRESS(f) (* (((gpointer*)(f)) + 1))
 276 #if MONO_ARCH_STACK_GROWS_UP
 277 #define IS_BEFORE_ON_STACK <
 278 #define IS_AFTER_ON_STACK >
 279 #else
 280 #define IS_BEFORE_ON_STACK >
 281 #define IS_AFTER_ON_STACK <
 282 #endif
 283 #else
 284 #define FULL_STAT_PROFILER_BACKTRACE 0
 285 #endif
 286
 287 #if defined(__ia64__) || defined(__sparc__) || defined(sparc) || defined(__s390__) || defined(s390)
 288
 289 static void
 290 SIG_HANDLER_SIGNATURE (sigprof_signal_handler)
 291 {
 292         if (mono_chain_signal (SIG_HANDLER_PARAMS))
 293                 return;
 294
 295         NOT_IMPLEMENTED;
 296 }
 297
 298 #else
 299
 300 static void
 301 SIG_HANDLER_SIGNATURE (sigprof_signal_handler)
 302 {
 303         int call_chain_depth = mono_profiler_stat_get_call_chain_depth ();
 304         MonoProfilerCallChainStrategy call_chain_strategy = mono_profiler_stat_get_call_chain_strategy ();
 305         GET_CONTEXT;
 306
 307         if (call_chain_depth == 0) {
 308                 mono_profiler_stat_hit (mono_arch_ip_from_context (ctx), ctx);
 309         } else {
 310                 MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
 311                 int current_frame_index = 1;
 312                 MonoContext mono_context;
 313                 guchar *ips [call_chain_depth + 1];
 314
 315                 mono_arch_sigctx_to_monoctx (ctx, &mono_context);
 316                 ips [0] = MONO_CONTEXT_GET_IP (&mono_context);
 317
 318                 if (jit_tls != NULL) {
 319                         if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_NATIVE) {
 320 #if FULL_STAT_PROFILER_BACKTRACE
 321                         guchar *current_frame;
 322                         guchar *stack_bottom;
 323                         guchar *stack_top;
 324
 325                         stack_bottom = jit_tls->end_of_stack;
 326                         stack_top = MONO_CONTEXT_GET_SP (&mono_context);
 327                         current_frame = MONO_CONTEXT_GET_BP (&mono_context);
 328
 329                         while ((current_frame_index <= call_chain_depth) &&
 330                                         (stack_bottom IS_BEFORE_ON_STACK (guchar*) current_frame) &&
 331                                         ((guchar*) current_frame IS_BEFORE_ON_STACK stack_top)) {
 332                                 ips [current_frame_index] = CURRENT_FRAME_GET_RETURN_ADDRESS (current_frame);
 333                                 current_frame_index ++;
 334                                 stack_top = current_frame;
 335                                 current_frame = CURRENT_FRAME_GET_BASE_POINTER (current_frame);
 336                         }
 337 #else
 338                                 call_chain_strategy = MONO_PROFILER_CALL_CHAIN_GLIBC;
 339 #endif
 340                         }
 341
 342                         if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_GLIBC) {
 343 #if GLIBC_PROFILER_BACKTRACE
 344                                 current_frame_index = backtrace ((void**) & ips [1], call_chain_depth);
 345 #else
 346                                 call_chain_strategy = MONO_PROFILER_CALL_CHAIN_MANAGED;
 347 #endif
 348                         }
 349
 350                         if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_MANAGED) {
 351                                 MonoDomain *domain = mono_domain_get ();
 352                                 if (domain != NULL) {
 353                                         MonoLMF *lmf = NULL;
 354                                         MonoJitInfo *ji;
 355                                         MonoJitInfo res;
 356                                         MonoContext new_mono_context;
 357                                         int native_offset;
 358                                         ji = mono_find_jit_info (domain, jit_tls, &res, NULL, &mono_context,
 359                                                         &new_mono_context, NULL, &lmf, &native_offset, NULL);
 360                                         while ((ji != NULL) && (current_frame_index <= call_chain_depth)) {
 361                                                 ips [current_frame_index] = MONO_CONTEXT_GET_IP (&new_mono_context);
 362                                                 current_frame_index ++;
 363                                                 mono_context = new_mono_context;
 364                                                 ji = mono_find_jit_info (domain, jit_tls, &res, NULL, &mono_context,
 365                                                                 &new_mono_context, NULL, &lmf, &native_offset, NULL);
 366                                         }
 367                                 }
 368                         }
 369                 }
 370
 371                 mono_profiler_stat_call_chain (current_frame_index, & ips [0], ctx);
 372         }
 373
 374         mono_chain_signal (SIG_HANDLER_PARAMS);
 375 }
 376
 377 #endif
 378
 379 static void
 380 SIG_HANDLER_SIGNATURE (sigquit_signal_handler)
 381 {
 382         gboolean res;
 383
 384         GET_CONTEXT;
 385
 386         /* We use this signal to start the attach agent too */
 387         res = mono_attach_start ();
 388         if (res)
 389                 return;
 390
 391         if (mono_thread_info_new_interrupt_enabled ()) {
 392                 mono_threads_request_thread_dump ();
 393         } else {
 394                 printf ("Full thread dump:\n");
 395
 396                 mono_threads_request_thread_dump ();
 397
 398                 /*
 399                  * print_thread_dump () skips the current thread, since sending a signal
 400                  * to it would invoke the signal handler below the sigquit signal handler,
 401                  * and signal handlers don't create an lmf, so the stack walk could not
 402                  * be performed.
 403                  */
 404                 mono_print_thread_dump (ctx);
 405         }
 406
 407         mono_chain_signal (SIG_HANDLER_PARAMS);
 408 }
 409
 410 static void
 411 SIG_HANDLER_SIGNATURE (sigusr2_signal_handler)
 412 {
 413         gboolean enabled = mono_trace_is_enabled ();
 414
 415         mono_trace_enable (!enabled);
 416
 417         mono_chain_signal (SIG_HANDLER_PARAMS);
 418 }
 419
 420 static void
 421 add_signal_handler (int signo, gpointer handler)
 422 {
 423         struct sigaction sa;
 424         struct sigaction previous_sa;
 425
 426 #ifdef MONO_ARCH_USE_SIGACTION
 427         sa.sa_sigaction = handler;
 428         sigemptyset (&sa.sa_mask);
 429         sa.sa_flags = SA_SIGINFO;
 430 #ifdef MONO_ARCH_SIGSEGV_ON_ALTSTACK
 431
 432 /*Apple likes to deliver SIGBUS for *0 */
 433 #ifdef __APPLE__
 434         if (signo == SIGSEGV || signo == SIGBUS) {
 435 #else
 436         if (signo == SIGSEGV) {
 437 #endif
 438                 sa.sa_flags |= SA_ONSTACK;
 439
 440                 /*
 441                  * libgc will crash when trying to do stack marking for threads which are on
 442                  * an altstack, so delay the suspend signal after the signal handler has
 443                  * executed.
 444                  */
 445                 if (mono_gc_get_suspend_signal () != -1)
 446                         sigaddset (&sa.sa_mask, mono_gc_get_suspend_signal ());
 447         }
 448 #endif
 449         if (signo == SIGSEGV) {
 450                 /*
 451                  * Delay abort signals while handling SIGSEGVs since they could go unnoticed.
 452                  */
 453                 sigset_t block_mask;
 454
 455                 sigemptyset (&block_mask);
 456                 sigaddset (&sa.sa_mask, mono_thread_get_abort_signal ());
 457         }
 458 #else
 459         sa.sa_handler = handler;
 460         sigemptyset (&sa.sa_mask);
 461         sa.sa_flags = 0;
 462 #endif
 463         g_assert (sigaction (signo, &sa, &previous_sa) != -1);
 464
 465         /* if there was already a handler in place for this signal, store it */
 466         if (! (previous_sa.sa_flags & SA_SIGINFO) &&
 467                         (SIG_DFL == previous_sa.sa_handler)) {
 468                 /* it there is no sa_sigaction function and the sa_handler is default, we can safely ignore this */
 469         } else {
 470                 if (mono_do_signal_chaining)
 471                         save_old_signal_handler (signo, &previous_sa);
 472         }
 473 }
 474
 475 static void
 476 remove_signal_handler (int signo)
 477 {
 478         struct sigaction sa;
 479         struct sigaction *saved_action = get_saved_signal_handler (signo);
 480
 481         if (!saved_action) {
 482                 sa.sa_handler = SIG_DFL;
 483                 sigemptyset (&sa.sa_mask);
 484                 sa.sa_flags = 0;
 485
 486                 sigaction (signo, &sa, NULL);
 487         } else {
 488                 g_assert (sigaction (signo, saved_action, NULL) != -1);
 489         }
 490 }
 491
 492 void
 493 mono_runtime_posix_install_handlers (void)
 494 {
 495
 496         sigset_t signal_set;
 497
 498         if (mini_get_debug_options ()->handle_sigint)
 499                 add_signal_handler (SIGINT, mono_sigint_signal_handler);
 500
 501         add_signal_handler (SIGFPE, mono_sigfpe_signal_handler);
 502         add_signal_handler (SIGQUIT, sigquit_signal_handler);
 503         add_signal_handler (SIGILL, mono_sigill_signal_handler);
 504         add_signal_handler (SIGBUS, mono_sigsegv_signal_handler);
 505         if (mono_jit_trace_calls != NULL)
 506                 add_signal_handler (SIGUSR2, sigusr2_signal_handler);
 507
 508         if (!mono_thread_info_new_interrupt_enabled ())
 509                 add_signal_handler (mono_thread_get_abort_signal (), sigusr1_signal_handler);
 510         /* it seems to have become a common bug for some programs that run as parents
 511          * of many processes to block signal delivery for real time signals.
 512          * We try to detect and work around their breakage here.
 513          */
 514         sigemptyset (&signal_set);
 515         sigaddset (&signal_set, mono_thread_get_abort_signal ());
 516         sigprocmask (SIG_UNBLOCK, &signal_set, NULL);
 517
 518         signal (SIGPIPE, SIG_IGN);
 519
 520         add_signal_handler (SIGABRT, sigabrt_signal_handler);
 521
 522         /* catch SIGSEGV */
 523         add_signal_handler (SIGSEGV, mono_sigsegv_signal_handler);
 524 }
 525
 526 #ifndef PLATFORM_MACOSX
 527 void
 528 mono_runtime_install_handlers (void)
 529 {
 530         mono_runtime_posix_install_handlers ();
 531 }
 532 #endif
 533
 534 void
 535 mono_runtime_cleanup_handlers (void)
 536 {
 537         if (mini_get_debug_options ()->handle_sigint)
 538                 remove_signal_handler (SIGINT);
 539
 540         remove_signal_handler (SIGFPE);
 541         remove_signal_handler (SIGQUIT);
 542         remove_signal_handler (SIGILL);
 543         remove_signal_handler (SIGBUS);
 544         if (mono_jit_trace_calls != NULL)
 545                 remove_signal_handler (SIGUSR2);
 546
 547         remove_signal_handler (mono_thread_get_abort_signal ());
 548
 549         remove_signal_handler (SIGABRT);
 550
 551         remove_signal_handler (SIGSEGV);
 552
 553         free_saved_signal_handlers ();
 554 }
 555
 556 #ifdef HAVE_LINUX_RTC_H
 557 #include <linux/rtc.h>
 558 #include <sys/ioctl.h>
 559 #include <fcntl.h>
 560 static int rtc_fd = -1;
 561
 562 static int
 563 enable_rtc_timer (gboolean enable)
 564 {
 565         int flags;
 566         flags = fcntl (rtc_fd, F_GETFL);
 567         if (flags < 0) {
 568                 perror ("getflags");
 569                 return 0;
 570         }
 571         if (enable)
 572                 flags |= FASYNC;
 573         else
 574                 flags &= ~FASYNC;
 575         if (fcntl (rtc_fd, F_SETFL, flags) == -1) {
 576                 perror ("setflags");
 577                 return 0;
 578         }
 579         return 1;
 580 }
 581 #endif
 582
 583 void
 584 mono_runtime_shutdown_stat_profiler (void)
 585 {
 586 #ifdef HAVE_LINUX_RTC_H
 587         if (rtc_fd >= 0)
 588                 enable_rtc_timer (FALSE);
 589 #endif
 590 }
 591
 592 void
 593 mono_runtime_setup_stat_profiler (void)
 594 {
 595 #ifdef ITIMER_PROF
 596         struct itimerval itval;
 597         static int inited = 0;
 598 #ifdef HAVE_LINUX_RTC_H
 599         const char *rtc_freq;
 600         if (!inited && (rtc_freq = g_getenv ("MONO_RTC"))) {
 601                 int freq = 0;
 602                 inited = 1;
 603                 if (*rtc_freq)
 604                         freq = atoi (rtc_freq);
 605                 if (!freq)
 606                         freq = 1024;
 607                 rtc_fd = open ("/dev/rtc", O_RDONLY);
 608                 if (rtc_fd == -1) {
 609                         perror ("open /dev/rtc");
 610                         return;
 611                 }
 612                 add_signal_handler (SIGPROF, sigprof_signal_handler);
 613                 if (ioctl (rtc_fd, RTC_IRQP_SET, freq) == -1) {
 614                         perror ("set rtc freq");
 615                         return;
 616                 }
 617                 if (ioctl (rtc_fd, RTC_PIE_ON, 0) == -1) {
 618                         perror ("start rtc");
 619                         return;
 620                 }
 621                 if (fcntl (rtc_fd, F_SETSIG, SIGPROF) == -1) {
 622                         perror ("setsig");
 623                         return;
 624                 }
 625                 if (fcntl (rtc_fd, F_SETOWN, getpid ()) == -1) {
 626                         perror ("setown");
 627                         return;
 628                 }
 629                 enable_rtc_timer (TRUE);
 630                 return;
 631         }
 632         if (rtc_fd >= 0)
 633                 return;
 634 #endif
 635
 636         itval.it_interval.tv_usec = 999;
 637         itval.it_interval.tv_sec = 0;
 638         itval.it_value = itval.it_interval;
 639         setitimer (ITIMER_PROF, &itval, NULL);
 640         if (inited)
 641                 return;
 642         inited = 1;
 643         add_signal_handler (SIGPROF, sigprof_signal_handler);
 644 #endif
 645 }
 646
 647 #if !defined(__APPLE__)
 648 pid_t
 649 mono_runtime_syscall_fork ()
 650 {
 651 #if defined(SYS_fork)
 652         return (pid_t) syscall (SYS_fork);
 653 #else
 654         g_assert_not_reached ();
 655         return 0;
 656 #endif
 657 }
 658
 659 void
 660 mono_gdb_render_native_backtraces (pid_t crashed_pid)
 661 {
 662         const char *argv [9];
 663         char buf1 [128];
 664
 665         argv [0] = g_find_program_in_path ("gdb");
 666         if (argv [0] == NULL) {
 667                 return;
 668         }
 669
 670         argv [1] = "-ex";
 671         sprintf (buf1, "attach %ld", (long) crashed_pid);
 672         argv [2] = buf1;
 673         argv [3] = "--ex";
 674         argv [4] = "info threads";
 675         argv [5] = "--ex";
 676         argv [6] = "thread apply all bt";
 677         argv [7] = "--batch";
 678         argv [8] = 0;
 679
 680         execv (argv [0], (char**)argv);
 681 }
 682 #endif
 683 #endif /* __native_client__ */
 684
 685 #if !defined (__MACH__)
 686
 687 gboolean
 688 mono_thread_state_init_from_handle (MonoThreadUnwindState *tctx, MonoNativeThreadId thread_id, MonoNativeThreadHandle thread_handle)
 689 {
 690         g_error ("Posix systems don't support mono_thread_state_init_from_handle");
 691         return FALSE;
 692 }
 693
 694 #endif