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_CONTEXT_SET_IP (&ctx, ves_icall_get_frame_info);
 126         MONO_CONTEXT_SET_BP (&ctx, __builtin_frame_address (0));
 127
 128         skip++;
 129
 130         do {
 131                 ji = mono_arch_find_jit_info (domain, jit_tls, &rji, NULL, &ctx, &new_ctx, NULL, &lmf, native_offset, NULL);
 132
 133                 ctx = new_ctx;
 134
 135                 if (!ji || ji == (gpointer)-1 || MONO_CONTEXT_GET_BP (&ctx) >= jit_tls->end_of_stack)
 136                         return FALSE;
 137
 138                 /* skip all wrappers ??*/
 139                 if (ji->method->wrapper_type == MONO_WRAPPER_RUNTIME_INVOKE ||
 140                     ji->method->wrapper_type == MONO_WRAPPER_REMOTING_INVOKE_WITH_CHECK ||
 141                     ji->method->wrapper_type == MONO_WRAPPER_REMOTING_INVOKE)
 142                         continue;
 143
 144                 skip--;
 145
 146         } while (skip >= 0);
 147
 148         *method = mono_method_get_object (domain, ji->method, NULL);
 149         *iloffset = mono_debug_il_offset_from_address (ji->method, *native_offset, domain);
 150
 151         if (need_file_info) {
 152                 gchar *filename;
 153
 154                 filename = mono_debug_source_location_from_address (ji->method, *native_offset, line, domain);
 155
 156                 *file = filename? mono_string_new (domain, filename): NULL;
 157                 *column = 0;
 158
 159                 g_free (filename);
 160         }
 161
 162         return TRUE;
 163 }
 164
 165 static MonoArray *
 166 glist_to_array (GList *list)
 167 {
 168         MonoDomain *domain = mono_domain_get ();
 169         MonoArray *res;
 170         int len, i;
 171
 172         if (!list)
 173                 return NULL;
 174
 175         len = g_list_length (list);
 176         res = mono_array_new (domain, mono_defaults.int_class, len);
 177
 178         for (i = 0; list; list = list->next, i++)
 179                 mono_array_set (res, gpointer, i, list->data);
 180
 181         return res;
 182 }
 183
 184 /**
 185  * mono_handle_exception:
 186  * @ctx: saved processor state
 187  * @obj: the exception object
 188  * @test_only: only test if the exception is caught, but dont call handlers
 189  *
 190  */
 191 gboolean
 192 mono_handle_exception (MonoContext *ctx, gpointer obj, gboolean test_only)
 193 {
 194         MonoDomain *domain = mono_domain_get ();
 195         MonoJitInfo *ji, rji;
 196         static int (*call_filter) (MonoContext *, gpointer) = NULL;
 197         static void (*restore_context) (struct sigcontext *);
 198         MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
 199         MonoLMF *lmf = jit_tls->lmf;
 200         GList *trace_ips = NULL;
 201         MonoException *mono_ex;
 202         gboolean stack_overflow = FALSE;
 203         MonoContext initial_ctx;
 204         int frame_count = 0;
 205         gboolean gc_disabled = FALSE;
 206         MonoString *initial_stack_trace;
 207
 208         /*
 209          * This function might execute on an alternate signal stack, and Boehm GC
 210          * can't handle that.
 211          * Also, since the altstack is small, stack space intensive operations like
 212          * JIT compilation should be avoided.
 213          */
 214         if (IS_ON_SIGALTSTACK (jit_tls)) {
 215                 /*
 216                  * FIXME: disabling/enabling GC while already on a signal stack might
 217                  * not be safe either.
 218                  */
 219                 /* Have to reenable it later */
 220                 gc_disabled = TRUE;
 221                 mono_gc_disable ();
 222         }
 223
 224         g_assert (ctx != NULL);
 225         if (!obj) {
 226                 MonoException *ex = mono_get_exception_null_reference ();
 227                 ex->message = mono_string_new (domain, "Object reference not set to an instance of an object");
 228                 obj = (MonoObject *)ex;
 229         }
 230
 231         /*
 232          * Allocate a new exception object instead of the preconstructed ones.
 233          * We can't do this in sigsegv_signal_handler, since GC is not yet
 234          * disabled.
 235          */
 236         if (obj == domain->stack_overflow_ex) {
 237                 obj = mono_get_exception_stack_overflow ();
 238         }
 239         else if (obj == domain->null_reference_ex) {
 240                 obj = mono_get_exception_null_reference ();
 241         }
 242
 243         if (mono_object_isinst (obj, mono_defaults.exception_class)) {
 244                 mono_ex = (MonoException*)obj;
 245                 initial_stack_trace = mono_ex->stack_trace;
 246         } else {
 247                 mono_ex = NULL;
 248         }
 249
 250         if (obj == domain->stack_overflow_ex)
 251                 stack_overflow = TRUE;
 252
 253         if (!call_filter)
 254                 call_filter = mono_arch_get_call_filter ();
 255
 256         if (!restore_context)
 257                 restore_context = mono_arch_get_restore_context ();
 258
 259         g_assert (jit_tls->end_of_stack);
 260         g_assert (jit_tls->abort_func);
 261
 262         if (!test_only) {
 263                 MonoContext ctx_cp = *ctx;
 264                 if (mono_jit_trace_calls != NULL)
 265                         g_print ("EXCEPTION handling: %s\n", mono_object_class (obj)->name);
 266                 if (!mono_handle_exception (&ctx_cp, obj, TRUE)) {
 267                         if (mono_break_on_exc)
 268                                 G_BREAKPOINT ();
 269                         mono_unhandled_exception (obj);
 270                 }
 271         }
 272
 273         initial_ctx = *ctx;
 274         memset (&rji, 0, sizeof (rji));
 275
 276         while (1) {
 277                 MonoContext new_ctx;
 278                 char *trace = NULL;
 279                 gboolean need_trace = FALSE;
 280                 guint32 free_stack;
 281
 282                 if (test_only && (frame_count < 1000))
 283                         need_trace = TRUE;
 284
 285                 ji = mono_arch_find_jit_info (domain, jit_tls, &rji, &rji, ctx, &new_ctx,
 286                                               need_trace ? &trace : NULL, &lmf, NULL, NULL);
 287                 if (!ji) {
 288                         g_warning ("Exception inside function without unwind info");
 289                         g_assert_not_reached ();
 290                 }
 291
 292                 if (ji != (gpointer)-1) {
 293                         frame_count ++;
 294                         //printf ("M: %s %p %p %d.\n", mono_method_full_name (ji->method, TRUE), jit_tls->end_of_stack, ctx->ebp, count);
 295
 296                         if (test_only && ji->method->wrapper_type != MONO_WRAPPER_RUNTIME_INVOKE && mono_ex) {
 297                                 char *tmp, *strace;
 298
 299                                 /*
 300                                  * Avoid overwriting the stack trace if the exception is
 301                                  * rethrown. Also avoid giant stack traces during a stack
 302                                  * overflow.
 303                                  */
 304                                 if (!initial_stack_trace && (frame_count < 1000)) {
 305                                         trace_ips = g_list_append (trace_ips, MONO_CONTEXT_GET_IP (ctx));
 306
 307                                         if (!mono_ex->stack_trace)
 308                                                 strace = g_strdup ("");
 309                                         else
 310                                                 strace = mono_string_to_utf8 (mono_ex->stack_trace);
 311
 312                                         tmp = g_strdup_printf ("%s%s\n", strace, trace);
 313                                         g_free (strace);
 314
 315                                         mono_ex->stack_trace = mono_string_new (domain, tmp);
 316
 317                                         g_free (tmp);
 318                                 }
 319                         }
 320
 321                         if (stack_overflow)
 322                                 free_stack = (guint8*)(MONO_CONTEXT_GET_BP (ctx)) - (guint8*)(MONO_CONTEXT_GET_BP (&initial_ctx));
 323                         else
 324                                 free_stack = 0xffffff;
 325
 326                         /*
 327                          * During stack overflow, wait till the unwinding frees some stack
 328                          * space before running handlers/finalizers.
 329                          */
 330                         if ((free_stack > (64 * 1024)) && ji->num_clauses) {
 331                                 int i;
 332
 333                                 g_assert (ji->clauses);
 334
 335                                 for (i = 0; i < ji->num_clauses; i++) {
 336                                         MonoJitExceptionInfo *ei = &ji->clauses [i];
 337
 338                                         if (ei->try_start <= MONO_CONTEXT_GET_IP (ctx) &&
 339                                             MONO_CONTEXT_GET_IP (ctx) <= ei->try_end) {
 340                                                 /* catch block */
 341
 342                                                 if ((ei->flags == MONO_EXCEPTION_CLAUSE_NONE) || (ei->flags == MONO_EXCEPTION_CLAUSE_FILTER)) {
 343                                                         /* store the exception object int cfg->excvar */
 344                                                         g_assert (ji->exvar_offset);
 345                                                         *((gpointer *)((char *)MONO_CONTEXT_GET_BP (ctx) + ji->exvar_offset)) = obj;
 346                                                 }
 347
 348                                                 if ((ei->flags == MONO_EXCEPTION_CLAUSE_NONE &&
 349                                                      mono_object_isinst (obj, mono_class_get (ji->method->klass->image, ei->data.token))) ||
 350                                                     ((ei->flags == MONO_EXCEPTION_CLAUSE_FILTER &&
 351                                                       call_filter (ctx, ei->data.filter)))) {
 352                                                         if (test_only) {
 353                                                                 if (mono_ex)
 354                                                                         mono_ex->trace_ips = glist_to_array (trace_ips);
 355                                                                 g_list_free (trace_ips);
 356                                                                 g_free (trace);
 357
 358                                                                 if (gc_disabled)
 359                                                                         mono_gc_enable ();
 360                                                                 return TRUE;
 361                                                         }
 362                                                         if (mono_jit_trace_calls != NULL && mono_trace_eval (ji->method))
 363                                                                 g_print ("EXCEPTION: catch found at clause %d of %s\n", i, mono_method_full_name (ji->method, TRUE));
 364                                                         MONO_CONTEXT_SET_IP (ctx, ei->handler_start);
 365                                                         jit_tls->lmf = lmf;
 366                                                         g_free (trace);
 367
 368                                                         if (gc_disabled)
 369                                                                 mono_gc_enable ();
 370                                                         return 0;
 371                                                 }
 372                                                 if (!test_only && ei->try_start <= MONO_CONTEXT_GET_IP (ctx) &&
 373                                                     MONO_CONTEXT_GET_IP (ctx) < ei->try_end &&
 374                                                     (ei->flags & MONO_EXCEPTION_CLAUSE_FINALLY)) {
 375                                                         if (mono_jit_trace_calls != NULL && mono_trace_eval (ji->method))
 376                                                                 g_print ("EXCEPTION: finally clause %d of %s\n", i, mono_method_full_name (ji->method, TRUE));
 377                                                         call_filter (ctx, ei->handler_start);
 378                                                 }
 379
 380                                         }
 381                                 }
 382                         }
 383                 }
 384
 385                 g_free (trace);
 386
 387                 *ctx = new_ctx;
 388
 389                 if ((ji == (gpointer)-1) || MONO_CONTEXT_GET_BP (ctx) >= jit_tls->end_of_stack) {
 390                         if (gc_disabled)
 391                                 mono_gc_enable ();
 392
 393                         if (!test_only) {
 394                                 jit_tls->lmf = lmf;
 395
 396                                 if (IS_ON_SIGALTSTACK (jit_tls)) {
 397                                         /* Switch back to normal stack */
 398                                         if (stack_overflow)
 399                                                 /* Free up some stack space */
 400                                                 MONO_CONTEXT_SET_SP (&initial_ctx, (guint32)(MONO_CONTEXT_GET_SP (&initial_ctx)) + (64 * 1024));
 401                                         MONO_CONTEXT_SET_IP (&initial_ctx, (unsigned int)jit_tls->abort_func);
 402                                         restore_context (&initial_ctx);
 403                                 }
 404                                 else
 405                                         jit_tls->abort_func (obj);
 406                                 g_assert_not_reached ();
 407                         } else {
 408                                 if (mono_ex)
 409                                         mono_ex->trace_ips = glist_to_array (trace_ips);
 410                                 g_list_free (trace_ips);
 411                                 return FALSE;
 412                         }
 413                 }
 414         }
 415
 416         g_assert_not_reached ();
 417 }