mono/mini/mini-exceptions.c

   1 /*
   2  * mini-exceptions.c: generic exception support
   3  *
   4  * Authors:
   5  *   Dietmar Maurer (dietmar@ximian.com)
   6  *
   7  * (C) 2001 Ximian, Inc.
   8  */
   9
  10 #include <config.h>
  11 #include <glib.h>
  12 #include <signal.h>
  13 #include <string.h>
  14
  15 #include <mono/metadata/appdomain.h>
  16 #include <mono/metadata/tabledefs.h>
  17 #include <mono/metadata/threads.h>
  18 #include <mono/metadata/debug-helpers.h>
  19 #include <mono/metadata/exception.h>
  20 #include <mono/metadata/gc-internal.h>
  21 #include <mono/metadata/mono-debug.h>
  22
  23 #include "mini.h"
  24
  25 #define IS_ON_SIGALTSTACK(jit_tls) ((jit_tls) && ((guint8*)&(jit_tls) > (guint8*)(jit_tls)->signal_stack) && ((guint8*)&(jit_tls) < ((guint8*)(jit_tls)->signal_stack + (jit_tls)->signal_stack_size)))
  26
  27 /* mono_find_jit_info:
  28  *
  29  * This function is used to gather information from @ctx. It return the
  30  * MonoJitInfo of the corresponding function, unwinds one stack frame and
  31  * stores the resulting context into @new_ctx. It also stores a string
  32  * describing the stack location into @trace (if not NULL), and modifies
  33  * the @lmf if necessary. @native_offset return the IP offset from the
  34  * start of the function or -1 if that info is not available.
  35  */
  36 static MonoJitInfo *
  37 mono_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls, MonoJitInfo *res, MonoJitInfo *prev_ji, MonoContext *ctx,
  38                          MonoContext *new_ctx, char **trace, MonoLMF **lmf, int *native_offset,
  39                          gboolean *managed)
  40 {
  41         gboolean managed2;
  42         gpointer ip = MONO_CONTEXT_GET_IP (ctx);
  43         MonoJitInfo *ji;
  44
  45         if (trace)
  46                 *trace = NULL;
  47
  48         if (native_offset)
  49                 *native_offset = -1;
  50
  51         if (managed)
  52                 *managed = FALSE;
  53
  54         ji = mono_arch_find_jit_info (domain, jit_tls, res, prev_ji, ctx, new_ctx, NULL, lmf, NULL, &managed2);
  55
  56         if (ji == (gpointer)-1)
  57                 return ji;
  58
  59         if (managed2 || ji->method->wrapper_type) {
  60                 char *source_location, *tmpaddr, *fname;
  61                 gint32 address, iloffset;
  62
  63                 address = (char *)ip - (char *)ji->code_start;
  64
  65                 if (native_offset)
  66                         *native_offset = address;
  67
  68                 if (managed)
  69                         if (!ji->method->wrapper_type)
  70                                 *managed = TRUE;
  71
  72                 if (trace) {
  73                         source_location = mono_debug_source_location_from_address (ji->method, address, NULL, domain);
  74                         iloffset = mono_debug_il_offset_from_address (ji->method, address, domain);
  75
  76                         if (iloffset < 0)
  77                                 tmpaddr = g_strdup_printf ("<0x%05x>", address);
  78                         else
  79                                 tmpaddr = g_strdup_printf ("[0x%05x]", iloffset);
  80
  81                         fname = mono_method_full_name (ji->method, TRUE);
  82
  83                         if (source_location)
  84                                 *trace = g_strdup_printf ("in %s (at %s) %s", tmpaddr, source_location, fname);
  85                         else
  86                                 *trace = g_strdup_printf ("in %s %s", tmpaddr, fname);
  87
  88                         g_free (fname);
  89                         g_free (source_location);
  90                         g_free (tmpaddr);
  91                 }
  92         }
  93         else {
  94                 if (trace) {
  95                         char *fname = mono_method_full_name (res->method, TRUE);
  96                         *trace = g_strdup_printf ("in (unmanaged) %s", fname);
  97                         g_free (fname);
  98                 }
  99         }
 100
 101         return ji;
 102 }
 103
 104 MonoArray *
 105 ves_icall_get_trace (MonoException *exc, gint32 skip, MonoBoolean need_file_info)
 106 {
 107         MonoDomain *domain = mono_domain_get ();
 108         MonoArray *res;
 109         MonoArray *ta = exc->trace_ips;
 110         int i, len;
 111
 112         if (ta == NULL) {
 113                 /* Exception is not thrown yet */
 114                 return mono_array_new (domain, mono_defaults.stack_frame_class, 0);
 115         }
 116
 117         len = mono_array_length (ta);
 118
 119         res = mono_array_new (domain, mono_defaults.stack_frame_class, len > skip ? len - skip : 0);
 120
 121         for (i = skip; i < len; i++) {
 122                 MonoJitInfo *ji;
 123                 MonoStackFrame *sf = (MonoStackFrame *)mono_object_new (domain, mono_defaults.stack_frame_class);
 124                 gpointer ip = mono_array_get (ta, gpointer, i);
 125
 126                 ji = mono_jit_info_table_find (domain, ip);
 127                 if (ji == NULL) {
 128                         /* Unmanaged frame */
 129                         mono_array_set (res, gpointer, i, sf);
 130                         continue;
 131                 }
 132
 133                 g_assert (ji != NULL);
 134
 135                 sf->method = mono_method_get_object (domain, ji->method, NULL);
 136                 sf->native_offset = (char *)ip - (char *)ji->code_start;
 137
 138                 sf->il_offset = mono_debug_il_offset_from_address (ji->method, sf->native_offset, domain);
 139
 140                 if (need_file_info) {
 141                         gchar *filename;
 142
 143                         filename = mono_debug_source_location_from_address (ji->method, sf->native_offset, &sf->line, domain);
 144
 145                         sf->filename = filename? mono_string_new (domain, filename): NULL;
 146                         sf->column = 0;
 147
 148                         g_free (filename);
 149                 }
 150
 151                 mono_array_set (res, gpointer, i, sf);
 152         }
 153
 154         return res;
 155 }
 156
 157 void
 158 mono_jit_walk_stack (MonoStackWalk func, gboolean do_il_offset, gpointer user_data) {
 159         MonoDomain *domain = mono_domain_get ();
 160         MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
 161         MonoLMF *lmf = jit_tls->lmf;
 162         MonoJitInfo *ji, rji;
 163         gint native_offset, il_offset;
 164         gboolean managed;
 165
 166         MonoContext ctx, new_ctx;
 167
 168         mono_arch_flush_register_windows ();
 169
 170         MONO_CONTEXT_SET_IP (&ctx, __builtin_return_address (0));
 171         MONO_CONTEXT_SET_BP (&ctx, __builtin_frame_address (1));
 172
 173         while (MONO_CONTEXT_GET_BP (&ctx) < jit_tls->end_of_stack) {
 174
 175                 ji = mono_find_jit_info (domain, jit_tls, &rji, NULL, &ctx, &new_ctx, NULL, &lmf, &native_offset, &managed);
 176                 g_assert (ji);
 177
 178                 if (ji == (gpointer)-1)
 179                         return;
 180
 181                 il_offset = do_il_offset ? mono_debug_il_offset_from_address (ji->method, native_offset, domain): -1;
 182
 183                 if (func (ji->method, native_offset, il_offset, managed, user_data))
 184                         return;
 185
 186                 ctx = new_ctx;
 187         }
 188 }
 189
 190 MonoBoolean
 191 ves_icall_get_frame_info (gint32 skip, MonoBoolean need_file_info,
 192                           MonoReflectionMethod **method,
 193                           gint32 *iloffset, gint32 *native_offset,
 194                           MonoString **file, gint32 *line, gint32 *column)
 195 {
 196         MonoDomain *domain = mono_domain_get ();
 197         MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
 198         MonoLMF *lmf = jit_tls->lmf;
 199         MonoJitInfo *ji, rji;
 200         MonoContext ctx, new_ctx;
 201
 202         mono_arch_flush_register_windows ();
 203
 204         MONO_CONTEXT_SET_IP (&ctx, ves_icall_get_frame_info);
 205         MONO_CONTEXT_SET_BP (&ctx, __builtin_frame_address (0));
 206
 207         skip++;
 208
 209         do {
 210                 ji = mono_find_jit_info (domain, jit_tls, &rji, NULL, &ctx, &new_ctx, NULL, &lmf, native_offset, NULL);
 211
 212                 ctx = new_ctx;
 213
 214                 if (!ji || ji == (gpointer)-1 || MONO_CONTEXT_GET_BP (&ctx) >= jit_tls->end_of_stack)
 215                         return FALSE;
 216
 217                 /* skip all wrappers ??*/
 218                 if (ji->method->wrapper_type == MONO_WRAPPER_RUNTIME_INVOKE ||
 219                     ji->method->wrapper_type == MONO_WRAPPER_XDOMAIN_INVOKE ||
 220                     ji->method->wrapper_type == MONO_WRAPPER_XDOMAIN_DISPATCH ||
 221                     ji->method->wrapper_type == MONO_WRAPPER_REMOTING_INVOKE_WITH_CHECK ||
 222                     ji->method->wrapper_type == MONO_WRAPPER_REMOTING_INVOKE)
 223                         continue;
 224
 225                 skip--;
 226
 227         } while (skip >= 0);
 228
 229         *method = mono_method_get_object (domain, ji->method, NULL);
 230         *iloffset = mono_debug_il_offset_from_address (ji->method, *native_offset, domain);
 231
 232         if (need_file_info) {
 233                 gchar *filename;
 234
 235                 filename = mono_debug_source_location_from_address (ji->method, *native_offset, line, domain);
 236
 237                 *file = filename? mono_string_new (domain, filename): NULL;
 238                 *column = 0;
 239
 240                 g_free (filename);
 241         }
 242
 243         return TRUE;
 244 }
 245
 246 static MonoArray *
 247 glist_to_array (GList *list)
 248 {
 249         MonoDomain *domain = mono_domain_get ();
 250         MonoArray *res;
 251         int len, i;
 252
 253         if (!list)
 254                 return NULL;
 255
 256         len = g_list_length (list);
 257         res = mono_array_new (domain, mono_defaults.int_class, len);
 258
 259         for (i = 0; list; list = list->next, i++)
 260                 mono_array_set (res, gpointer, i, list->data);
 261
 262         return res;
 263 }
 264
 265 /**
 266  * mono_handle_exception:
 267  * @ctx: saved processor state
 268  * @obj: the exception object
 269  * @test_only: only test if the exception is caught, but dont call handlers
 270  *
 271  */
 272 gboolean
 273 mono_handle_exception (MonoContext *ctx, gpointer obj, gpointer original_ip, gboolean test_only)
 274 {
 275         MonoDomain *domain = mono_domain_get ();
 276         MonoJitInfo *ji, rji;
 277         static int (*call_filter) (MonoContext *, gpointer) = NULL;
 278         static void (*restore_context) (void *);
 279         MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
 280         MonoLMF *lmf = jit_tls->lmf;
 281         GList *trace_ips = NULL;
 282         MonoException *mono_ex;
 283         gboolean stack_overflow = FALSE;
 284         MonoContext initial_ctx;
 285         int frame_count = 0;
 286         gboolean gc_disabled = FALSE;
 287         MonoString *initial_stack_trace = NULL;
 288         GString *trace_str = NULL;
 289
 290         /*
 291          * This function might execute on an alternate signal stack, and Boehm GC
 292          * can't handle that.
 293          * Also, since the altstack is small, stack space intensive operations like
 294          * JIT compilation should be avoided.
 295          */
 296         if (IS_ON_SIGALTSTACK (jit_tls)) {
 297                 /*
 298                  * FIXME: disabling/enabling GC while already on a signal stack might
 299                  * not be safe either.
 300                  */
 301                 /* Have to reenable it later */
 302                 gc_disabled = TRUE;
 303                 mono_gc_disable ();
 304         }
 305
 306         g_assert (ctx != NULL);
 307         if (!obj) {
 308                 MonoException *ex = mono_get_exception_null_reference ();
 309                 ex->message = mono_string_new (domain, "Object reference not set to an instance of an object");
 310                 obj = (MonoObject *)ex;
 311         }
 312
 313         /*
 314          * Allocate a new exception object instead of the preconstructed ones.
 315          * We can't do this in sigsegv_signal_handler, since GC is not yet
 316          * disabled.
 317          */
 318         if (obj == domain->stack_overflow_ex) {
 319                 obj = mono_get_exception_stack_overflow ();
 320         }
 321         else if (obj == domain->null_reference_ex) {
 322                 obj = mono_get_exception_null_reference ();
 323         }
 324
 325         if (mono_object_isinst (obj, mono_defaults.exception_class)) {
 326                 mono_ex = (MonoException*)obj;
 327                 initial_stack_trace = mono_ex->stack_trace;
 328         } else {
 329                 mono_ex = NULL;
 330         }
 331
 332         if (obj == domain->stack_overflow_ex)
 333                 stack_overflow = TRUE;
 334
 335         if (!call_filter)
 336                 call_filter = mono_arch_get_call_filter ();
 337
 338         if (!restore_context)
 339                 restore_context = mono_arch_get_restore_context ();
 340
 341         g_assert (jit_tls->end_of_stack);
 342         g_assert (jit_tls->abort_func);
 343
 344         if (!test_only) {
 345                 MonoContext ctx_cp = *ctx;
 346                 if (mono_jit_trace_calls != NULL)
 347                         g_print ("EXCEPTION handling: %s\n", mono_object_class (obj)->name);
 348                 if (!mono_handle_exception (&ctx_cp, obj, original_ip, TRUE)) {
 349                         if (mono_break_on_exc)
 350                                 G_BREAKPOINT ();
 351                         mono_unhandled_exception (obj);
 352
 353                         if (mono_debugger_unhandled_exception (original_ip, MONO_CONTEXT_GET_SP (ctx), obj)) {
 354                                 /*
 355                                  * If this returns true, then we're running inside the
 356                                  * Mono Debugger and the debugger wants us to restore the
 357                                  * context and continue (normally, the debugger inserts
 358                                  * a breakpoint on the `original_ip', so it regains control
 359                                  * immediately after restoring the context).
 360                                  */
 361                                 MONO_CONTEXT_SET_IP (ctx, original_ip);
 362                                 restore_context (ctx);
 363                                 g_assert_not_reached ();
 364                         }
 365                 }
 366         }
 367
 368         initial_ctx = *ctx;
 369         memset (&rji, 0, sizeof (rji));
 370
 371         while (1) {
 372                 MonoContext new_ctx;
 373                 char *trace = NULL;
 374                 gboolean need_trace = FALSE;
 375                 guint32 free_stack;
 376
 377                 if (test_only && (frame_count < 1000)) {
 378                         need_trace = TRUE;
 379                         if (!trace_str)
 380                                 trace_str = g_string_new ("");
 381                 }
 382
 383                 ji = mono_find_jit_info (domain, jit_tls, &rji, &rji, ctx, &new_ctx,
 384                                                                  need_trace ? &trace : NULL, &lmf, NULL, NULL);
 385                 if (!ji) {
 386                         g_warning ("Exception inside function without unwind info");
 387                         g_assert_not_reached ();
 388                 }
 389
 390                 if (ji != (gpointer)-1) {
 391                         frame_count ++;
 392                         //printf ("M: %s %d %d.\n", mono_method_full_name (ji->method, TRUE), frame_count, test_only);
 393
 394                         if (test_only && ji->method->wrapper_type != MONO_WRAPPER_RUNTIME_INVOKE && mono_ex) {
 395                                 /*
 396                                  * Avoid overwriting the stack trace if the exception is
 397                                  * rethrown. Also avoid giant stack traces during a stack
 398                                  * overflow.
 399                                  */
 400                                 if (!initial_stack_trace && (frame_count < 1000)) {
 401                                         trace_ips = g_list_prepend (trace_ips, MONO_CONTEXT_GET_IP (ctx));
 402
 403                                         g_string_append (trace_str, trace);
 404                                         g_string_append_c (trace_str, '\n');
 405                                 }
 406                         }
 407
 408                         if (stack_overflow)
 409                                 free_stack = (guint8*)(MONO_CONTEXT_GET_BP (ctx)) - (guint8*)(MONO_CONTEXT_GET_BP (&initial_ctx));
 410                         else
 411                                 free_stack = 0xffffff;
 412
 413                         /*
 414                          * During stack overflow, wait till the unwinding frees some stack
 415                          * space before running handlers/finalizers.
 416                          */
 417                         if ((free_stack > (64 * 1024)) && ji->num_clauses) {
 418                                 int i;
 419
 420                                 g_assert (ji->clauses);
 421
 422                                 for (i = 0; i < ji->num_clauses; i++) {
 423                                         MonoJitExceptionInfo *ei = &ji->clauses [i];
 424                                         gboolean filtered = FALSE;
 425
 426                                         if (ei->try_start <= MONO_CONTEXT_GET_IP (ctx) &&
 427                                             MONO_CONTEXT_GET_IP (ctx) <= ei->try_end) {
 428                                                 /* catch block */
 429
 430                                                 if ((ei->flags == MONO_EXCEPTION_CLAUSE_NONE) || (ei->flags == MONO_EXCEPTION_CLAUSE_FILTER)) {
 431                                                         /* store the exception object int cfg->excvar */
 432                                                         g_assert (ji->exvar_offset);
 433                                                         *((gpointer *)((char *)MONO_CONTEXT_GET_BP (ctx) + ji->exvar_offset)) = obj;
 434                                                         if (!initial_stack_trace && trace_str) {
 435                                                                 mono_ex->stack_trace = mono_string_new (domain, trace_str->str);
 436                                                         }
 437                                                 }
 438
 439                                                 if (ei->flags == MONO_EXCEPTION_CLAUSE_FILTER) {
 440                                                         mono_debugger_handle_exception (ei->data.filter, MONO_CONTEXT_GET_SP (ctx), obj);
 441                                                         filtered = call_filter (ctx, ei->data.filter);
 442                                                 }
 443
 444                                                 if ((ei->flags == MONO_EXCEPTION_CLAUSE_NONE &&
 445                                                      mono_object_isinst (obj, ei->data.catch_class)) || filtered) {
 446                                                         if (test_only) {
 447                                                                 if (mono_ex) {
 448                                                                         trace_ips = g_list_reverse (trace_ips);
 449                                                                         mono_ex->trace_ips = glist_to_array (trace_ips);
 450                                                                 }
 451                                                                 g_list_free (trace_ips);
 452                                                                 g_free (trace);
 453
 454                                                                 if (gc_disabled)
 455                                                                         mono_gc_enable ();
 456                                                                 if (trace_str)
 457                                                                         g_string_free (trace_str, TRUE);
 458                                                                 return TRUE;
 459                                                         }
 460                                                         if (mono_jit_trace_calls != NULL && mono_trace_eval (ji->method))
 461                                                                 g_print ("EXCEPTION: catch found at clause %d of %s\n", i, mono_method_full_name (ji->method, TRUE));
 462                                                         mono_debugger_handle_exception (ei->handler_start, MONO_CONTEXT_GET_SP (ctx), obj);
 463                                                         MONO_CONTEXT_SET_IP (ctx, ei->handler_start);
 464                                                         jit_tls->lmf = lmf;
 465                                                         g_free (trace);
 466
 467                                                         if (gc_disabled)
 468                                                                 mono_gc_enable ();
 469                                                         if (trace_str)
 470                                                                 g_string_free (trace_str, TRUE);
 471                                                         return 0;
 472                                                 }
 473                                                 if (!test_only && ei->try_start <= MONO_CONTEXT_GET_IP (ctx) &&
 474                                                     MONO_CONTEXT_GET_IP (ctx) < ei->try_end &&
 475                                                     (ei->flags & MONO_EXCEPTION_CLAUSE_FINALLY)) {
 476                                                         if (mono_jit_trace_calls != NULL && mono_trace_eval (ji->method))
 477                                                                 g_print ("EXCEPTION: finally clause %d of %s\n", i, mono_method_full_name (ji->method, TRUE));
 478                                                         mono_debugger_handle_exception (ei->handler_start, MONO_CONTEXT_GET_SP (ctx), obj);
 479                                                         call_filter (ctx, ei->handler_start);
 480                                                 }
 481
 482                                         }
 483                                 }
 484                         }
 485                 }
 486
 487                 g_free (trace);
 488
 489                 *ctx = new_ctx;
 490
 491                 if ((ji == (gpointer)-1) || MONO_CONTEXT_GET_BP (ctx) >= jit_tls->end_of_stack) {
 492                         if (gc_disabled)
 493                                 mono_gc_enable ();
 494
 495                         if (!test_only) {
 496                                 jit_tls->lmf = lmf;
 497
 498                                 if (IS_ON_SIGALTSTACK (jit_tls)) {
 499                                         /* Switch back to normal stack */
 500                                         if (stack_overflow)
 501                                                 /* Free up some stack space */
 502                                                 MONO_CONTEXT_SET_SP (&initial_ctx, (guint32)(MONO_CONTEXT_GET_SP (&initial_ctx)) + (64 * 1024));
 503                                         MONO_CONTEXT_SET_IP (&initial_ctx, (unsigned int)jit_tls->abort_func);
 504                                         restore_context (&initial_ctx);
 505                                 }
 506                                 else
 507                                         jit_tls->abort_func (obj);
 508                                 g_assert_not_reached ();
 509                         } else {
 510                                 if (mono_ex) {
 511                                         trace_ips = g_list_reverse (trace_ips);
 512                                         mono_ex->trace_ips = glist_to_array (trace_ips);
 513                                 }
 514                                 g_list_free (trace_ips);
 515                                 if (trace_str)
 516                                         g_string_free (trace_str, TRUE);
 517                                 return FALSE;
 518                         }
 519                 }
 520         }
 521
 522         g_assert_not_reached ();
 523 }