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 MonoArray *
  28 ves_icall_get_trace (MonoException *exc, gint32 skip, MonoBoolean need_file_info)
  29 {
  30         MonoDomain *domain = mono_domain_get ();
  31         MonoArray *res;
  32         MonoArray *ta = exc->trace_ips;
  33         int i, len;
  34
  35         if (ta == NULL) {
  36                 /* Exception is not thrown yet */
  37                 return mono_array_new (domain, mono_defaults.stack_frame_class, 0);
  38         }
  39
  40         len = mono_array_length (ta);
  41
  42         res = mono_array_new (domain, mono_defaults.stack_frame_class, len > skip ? len - skip : 0);
  43
  44         for (i = skip; i < len; i++) {
  45                 MonoJitInfo *ji;
  46                 MonoStackFrame *sf = (MonoStackFrame *)mono_object_new (domain, mono_defaults.stack_frame_class);
  47                 gpointer ip = mono_array_get (ta, gpointer, i);
  48
  49                 ji = mono_jit_info_table_find (domain, ip);
  50                 if (ji == NULL) {
  51                         /* Unmanaged frame */
  52                         mono_array_set (res, gpointer, i, sf);
  53                         continue;
  54                 }
  55
  56                 g_assert (ji != NULL);
  57
  58                 sf->method = mono_method_get_object (domain, ji->method, NULL);
  59                 sf->native_offset = (char *)ip - (char *)ji->code_start;
  60
  61                 sf->il_offset = mono_debug_il_offset_from_address (ji->method, sf->native_offset, domain);
  62
  63                 if (need_file_info) {
  64                         gchar *filename;
  65
  66                         filename = mono_debug_source_location_from_address (ji->method, sf->native_offset, &sf->line, domain);
  67
  68                         sf->filename = filename? mono_string_new (domain, filename): NULL;
  69                         sf->column = 0;
  70
  71                         g_free (filename);
  72                 }
  73
  74                 mono_array_set (res, gpointer, i, sf);
  75         }
  76
  77         return res;
  78 }
  79
  80 void
  81 mono_jit_walk_stack (MonoStackWalk func, gpointer user_data) {
  82         MonoDomain *domain = mono_domain_get ();
  83         MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
  84         MonoLMF *lmf = jit_tls->lmf;
  85         MonoJitInfo *ji, rji;
  86         gint native_offset, il_offset;
  87         gboolean managed;
  88
  89         MonoContext ctx, new_ctx;
  90
  91         mono_arch_flush_register_windows ();
  92
  93         MONO_CONTEXT_SET_IP (&ctx, __builtin_return_address (0));
  94         MONO_CONTEXT_SET_BP (&ctx, __builtin_frame_address (1));
  95
  96         while (MONO_CONTEXT_GET_BP (&ctx) < jit_tls->end_of_stack) {
  97
  98                 ji = mono_arch_find_jit_info (domain, jit_tls, &rji, NULL, &ctx, &new_ctx, NULL, &lmf, &native_offset, &managed);
  99                 g_assert (ji);
 100
 101                 if (ji == (gpointer)-1)
 102                         return;
 103
 104                 il_offset = mono_debug_il_offset_from_address (ji->method, native_offset, domain);
 105
 106                 if (func (ji->method, native_offset, il_offset, managed, user_data))
 107                         return;
 108
 109                 ctx = new_ctx;
 110         }
 111 }
 112
 113 MonoBoolean
 114 ves_icall_get_frame_info (gint32 skip, MonoBoolean need_file_info,
 115                           MonoReflectionMethod **method,
 116                           gint32 *iloffset, gint32 *native_offset,
 117                           MonoString **file, gint32 *line, gint32 *column)
 118 {
 119         MonoDomain *domain = mono_domain_get ();
 120         MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
 121         MonoLMF *lmf = jit_tls->lmf;
 122         MonoJitInfo *ji, rji;
 123         MonoContext ctx, new_ctx;
 124
 125         mono_arch_flush_register_windows ();
 126
 127         MONO_CONTEXT_SET_IP (&ctx, ves_icall_get_frame_info);
 128         MONO_CONTEXT_SET_BP (&ctx, __builtin_frame_address (0));
 129
 130         skip++;
 131
 132         do {
 133                 ji = mono_arch_find_jit_info (domain, jit_tls, &rji, NULL, &ctx, &new_ctx, NULL, &lmf, native_offset, NULL);
 134
 135                 ctx = new_ctx;
 136
 137                 if (!ji || ji == (gpointer)-1 || MONO_CONTEXT_GET_BP (&ctx) >= jit_tls->end_of_stack)
 138                         return FALSE;
 139
 140                 /* skip all wrappers ??*/
 141                 if (ji->method->wrapper_type == MONO_WRAPPER_RUNTIME_INVOKE ||
 142                     ji->method->wrapper_type == MONO_WRAPPER_REMOTING_INVOKE_WITH_CHECK ||
 143                     ji->method->wrapper_type == MONO_WRAPPER_REMOTING_INVOKE)
 144                         continue;
 145
 146                 skip--;
 147
 148         } while (skip >= 0);
 149
 150         *method = mono_method_get_object (domain, ji->method, NULL);
 151         *iloffset = mono_debug_il_offset_from_address (ji->method, *native_offset, domain);
 152
 153         if (need_file_info) {
 154                 gchar *filename;
 155
 156                 filename = mono_debug_source_location_from_address (ji->method, *native_offset, line, domain);
 157
 158                 *file = filename? mono_string_new (domain, filename): NULL;
 159                 *column = 0;
 160
 161                 g_free (filename);
 162         }
 163
 164         return TRUE;
 165 }
 166
 167 static MonoArray *
 168 glist_to_array (GList *list)
 169 {
 170         MonoDomain *domain = mono_domain_get ();
 171         MonoArray *res;
 172         int len, i;
 173
 174         if (!list)
 175                 return NULL;
 176
 177         len = g_list_length (list);
 178         res = mono_array_new (domain, mono_defaults.int_class, len);
 179
 180         for (i = 0; list; list = list->next, i++)
 181                 mono_array_set (res, gpointer, i, list->data);
 182
 183         return res;
 184 }
 185
 186 /**
 187  * mono_handle_exception:
 188  * @ctx: saved processor state
 189  * @obj: the exception object
 190  * @test_only: only test if the exception is caught, but dont call handlers
 191  *
 192  */
 193 gboolean
 194 mono_handle_exception (MonoContext *ctx, gpointer obj, gpointer original_ip, gboolean test_only)
 195 {
 196         MonoDomain *domain = mono_domain_get ();
 197         MonoJitInfo *ji, rji;
 198         static int (*call_filter) (MonoContext *, gpointer) = NULL;
 199         static void (*restore_context) (void *);
 200         MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
 201         MonoLMF *lmf = jit_tls->lmf;
 202         GList *trace_ips = NULL;
 203         MonoException *mono_ex;
 204         gboolean stack_overflow = FALSE;
 205         MonoContext initial_ctx;
 206         int frame_count = 0;
 207         gboolean gc_disabled = FALSE;
 208         MonoString *initial_stack_trace;
 209
 210         /*
 211          * This function might execute on an alternate signal stack, and Boehm GC
 212          * can't handle that.
 213          * Also, since the altstack is small, stack space intensive operations like
 214          * JIT compilation should be avoided.
 215          */
 216         if (IS_ON_SIGALTSTACK (jit_tls)) {
 217                 /*
 218                  * FIXME: disabling/enabling GC while already on a signal stack might
 219                  * not be safe either.
 220                  */
 221                 /* Have to reenable it later */
 222                 gc_disabled = TRUE;
 223                 mono_gc_disable ();
 224         }
 225
 226         g_assert (ctx != NULL);
 227         if (!obj) {
 228                 MonoException *ex = mono_get_exception_null_reference ();
 229                 ex->message = mono_string_new (domain, "Object reference not set to an instance of an object");
 230                 obj = (MonoObject *)ex;
 231         }
 232
 233         /*
 234          * Allocate a new exception object instead of the preconstructed ones.
 235          * We can't do this in sigsegv_signal_handler, since GC is not yet
 236          * disabled.
 237          */
 238         if (obj == domain->stack_overflow_ex) {
 239                 obj = mono_get_exception_stack_overflow ();
 240         }
 241         else if (obj == domain->null_reference_ex) {
 242                 obj = mono_get_exception_null_reference ();
 243         }
 244
 245         if (mono_object_isinst (obj, mono_defaults.exception_class)) {
 246                 mono_ex = (MonoException*)obj;
 247                 initial_stack_trace = mono_ex->stack_trace;
 248         } else {
 249                 mono_ex = NULL;
 250         }
 251
 252         if (obj == domain->stack_overflow_ex)
 253                 stack_overflow = TRUE;
 254
 255         if (!call_filter)
 256                 call_filter = mono_arch_get_call_filter ();
 257
 258         if (!restore_context)
 259                 restore_context = mono_arch_get_restore_context ();
 260
 261         g_assert (jit_tls->end_of_stack);
 262         g_assert (jit_tls->abort_func);
 263
 264         if (!test_only) {
 265                 MonoContext ctx_cp = *ctx;
 266                 if (mono_jit_trace_calls != NULL)
 267                         g_print ("EXCEPTION handling: %s\n", mono_object_class (obj)->name);
 268                 if (!mono_handle_exception (&ctx_cp, obj, original_ip, TRUE)) {
 269                         if (mono_break_on_exc)
 270                                 G_BREAKPOINT ();
 271                         mono_unhandled_exception (obj);
 272
 273                         if (mono_debugger_unhandled_exception (original_ip, obj)) {
 274                                 /*
 275                                  * If this returns true, then we're running inside the
 276                                  * Mono Debugger and the debugger wants us to restore the
 277                                  * context and continue (normally, the debugger inserts
 278                                  * a breakpoint on the `original_ip', so it regains control
 279                                  * immediately after restoring the context).
 280                                  */
 281                                 MONO_CONTEXT_SET_IP (ctx, original_ip);
 282                                 restore_context (ctx);
 283                                 g_assert_not_reached ();
 284                         }
 285                 }
 286         }
 287
 288         initial_ctx = *ctx;
 289         memset (&rji, 0, sizeof (rji));
 290
 291         while (1) {
 292                 MonoContext new_ctx;
 293                 char *trace = NULL;
 294                 gboolean need_trace = FALSE;
 295                 guint32 free_stack;
 296
 297                 if (test_only && (frame_count < 1000))
 298                         need_trace = TRUE;
 299
 300                 ji = mono_arch_find_jit_info (domain, jit_tls, &rji, &rji, ctx, &new_ctx,
 301                                               need_trace ? &trace : NULL, &lmf, NULL, NULL);
 302                 if (!ji) {
 303                         g_warning ("Exception inside function without unwind info");
 304                         g_assert_not_reached ();
 305                 }
 306
 307                 if (ji != (gpointer)-1) {
 308                         frame_count ++;
 309                         //printf ("M: %s %d %d.\n", mono_method_full_name (ji->method, TRUE), frame_count, test_only);
 310
 311                         if (test_only && ji->method->wrapper_type != MONO_WRAPPER_RUNTIME_INVOKE && mono_ex) {
 312                                 char *tmp, *strace;
 313
 314                                 /*
 315                                  * Avoid overwriting the stack trace if the exception is
 316                                  * rethrown. Also avoid giant stack traces during a stack
 317                                  * overflow.
 318                                  */
 319                                 if (!initial_stack_trace && (frame_count < 1000)) {
 320                                         trace_ips = g_list_append (trace_ips, MONO_CONTEXT_GET_IP (ctx));
 321
 322                                         if (!mono_ex->stack_trace)
 323                                                 strace = g_strdup ("");
 324                                         else
 325                                                 strace = mono_string_to_utf8 (mono_ex->stack_trace);
 326
 327                                         tmp = g_strdup_printf ("%s%s\n", strace, trace);
 328                                         g_free (strace);
 329
 330                                         mono_ex->stack_trace = mono_string_new (domain, tmp);
 331
 332                                         g_free (tmp);
 333                                 }
 334                         }
 335
 336                         if (stack_overflow)
 337                                 free_stack = (guint8*)(MONO_CONTEXT_GET_BP (ctx)) - (guint8*)(MONO_CONTEXT_GET_BP (&initial_ctx));
 338                         else
 339                                 free_stack = 0xffffff;
 340
 341                         /*
 342                          * During stack overflow, wait till the unwinding frees some stack
 343                          * space before running handlers/finalizers.
 344                          */
 345                         if ((free_stack > (64 * 1024)) && ji->num_clauses) {
 346                                 int i;
 347
 348                                 g_assert (ji->clauses);
 349
 350                                 for (i = 0; i < ji->num_clauses; i++) {
 351                                         MonoJitExceptionInfo *ei = &ji->clauses [i];
 352                                         gboolean filtered = FALSE;
 353
 354                                         if (ei->try_start <= MONO_CONTEXT_GET_IP (ctx) &&
 355                                             MONO_CONTEXT_GET_IP (ctx) <= ei->try_end) {
 356                                                 /* catch block */
 357
 358                                                 if ((ei->flags == MONO_EXCEPTION_CLAUSE_NONE) || (ei->flags == MONO_EXCEPTION_CLAUSE_FILTER)) {
 359                                                         /* store the exception object int cfg->excvar */
 360                                                         g_assert (ji->exvar_offset);
 361                                                         *((gpointer *)((char *)MONO_CONTEXT_GET_BP (ctx) + ji->exvar_offset)) = obj;
 362                                                 }
 363
 364                                                 if (ei->flags == MONO_EXCEPTION_CLAUSE_FILTER)
 365                                                         filtered = call_filter (ctx, ei->data.filter);
 366
 367                                                 if ((ei->flags == MONO_EXCEPTION_CLAUSE_NONE &&
 368                                                      mono_object_isinst (obj, mono_class_get (ji->method->klass->image, ei->data.token))) || filtered) {
 369                                                         if (test_only) {
 370                                                                 if (mono_ex)
 371                                                                         mono_ex->trace_ips = glist_to_array (trace_ips);
 372                                                                 g_list_free (trace_ips);
 373                                                                 g_free (trace);
 374
 375                                                                 if (gc_disabled)
 376                                                                         mono_gc_enable ();
 377                                                                 return TRUE;
 378                                                         }
 379                                                         if (mono_jit_trace_calls != NULL && mono_trace_eval (ji->method))
 380                                                                 g_print ("EXCEPTION: catch found at clause %d of %s\n", i, mono_method_full_name (ji->method, TRUE));
 381                                                         MONO_CONTEXT_SET_IP (ctx, ei->handler_start);
 382                                                         jit_tls->lmf = lmf;
 383                                                         g_free (trace);
 384
 385                                                         if (gc_disabled)
 386                                                                 mono_gc_enable ();
 387                                                         return 0;
 388                                                 }
 389                                                 if (!test_only && ei->try_start <= MONO_CONTEXT_GET_IP (ctx) &&
 390                                                     MONO_CONTEXT_GET_IP (ctx) < ei->try_end &&
 391                                                     (ei->flags & MONO_EXCEPTION_CLAUSE_FINALLY)) {
 392                                                         if (mono_jit_trace_calls != NULL && mono_trace_eval (ji->method))
 393                                                                 g_print ("EXCEPTION: finally clause %d of %s\n", i, mono_method_full_name (ji->method, TRUE));
 394                                                         call_filter (ctx, ei->handler_start);
 395                                                 }
 396
 397                                         }
 398                                 }
 399                         }
 400                 }
 401
 402                 g_free (trace);
 403
 404                 *ctx = new_ctx;
 405
 406                 if ((ji == (gpointer)-1) || MONO_CONTEXT_GET_BP (ctx) >= jit_tls->end_of_stack) {
 407                         if (gc_disabled)
 408                                 mono_gc_enable ();
 409
 410                         if (!test_only) {
 411                                 jit_tls->lmf = lmf;
 412
 413                                 if (IS_ON_SIGALTSTACK (jit_tls)) {
 414                                         /* Switch back to normal stack */
 415                                         if (stack_overflow)
 416                                                 /* Free up some stack space */
 417                                                 MONO_CONTEXT_SET_SP (&initial_ctx, (guint32)(MONO_CONTEXT_GET_SP (&initial_ctx)) + (64 * 1024));
 418                                         MONO_CONTEXT_SET_IP (&initial_ctx, (unsigned int)jit_tls->abort_func);
 419                                         restore_context (&initial_ctx);
 420                                 }
 421                                 else
 422                                         jit_tls->abort_func (obj);
 423                                 g_assert_not_reached ();
 424                         } else {
 425                                 if (mono_ex)
 426                                         mono_ex->trace_ips = glist_to_array (trace_ips);
 427                                 g_list_free (trace_ips);
 428                                 return FALSE;
 429                         }
 430                 }
 431         }
 432
 433         g_assert_not_reached ();
 434 }