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