dlls/msvcrt/cppexcept.c

   1 /*
   2  * msvcrt C++ exception handling
   3  *
   4  * Copyright 2002 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * NOTES
  21  * A good reference is the article "How a C++ compiler implements
  22  * exception handling" by Vishal Kochhar, available on
  23  * www.thecodeproject.com.
  24  */
  25
  26 #include "config.h"
  27 #include "wine/port.h"
  28
  29 #include <stdarg.h>
  30
  31 #include "windef.h"
  32 #include "winbase.h"
  33 #include "winternl.h"
  34 #include "msvcrt.h"
  35 #include "wine/exception.h"
  36 #include "excpt.h"
  37 #include "wine/debug.h"
  38
  39 #include "cppexcept.h"
  40
  41 #ifdef __i386__  /* CxxFrameHandler is not supported on non-i386 */
  42
  43 WINE_DEFAULT_DEBUG_CHANNEL(seh);
  44
  45 DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
  46                                PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
  47                                const cxx_function_descr *descr,
  48                                EXCEPTION_REGISTRATION_RECORD* nested_frame, int nested_trylevel );
  49
  50 /* call a function with a given ebp */
  51 static inline void *call_ebp_func( void *func, void *ebp )
  52 {
  53     void *ret;
  54     int dummy;
  55     __asm__ __volatile__ ("pushl %%ebx\n\t"
  56                           "pushl %%ebp\n\t"
  57                           "movl %4,%%ebp\n\t"
  58                           "call *%%eax\n\t"
  59                           "popl %%ebp\n\t"
  60                           "popl %%ebx"
  61                           : "=a" (ret), "=S" (dummy), "=D" (dummy)
  62                           : "0" (func), "1" (ebp) : "ecx", "edx", "memory" );
  63     return ret;
  64 }
  65
  66 /* call a copy constructor */
  67 static inline void call_copy_ctor( void *func, void *this, void *src, int has_vbase )
  68 {
  69     TRACE( "calling copy ctor %p object %p src %p\n", func, this, src );
  70     if (has_vbase)
  71         /* in that case copy ctor takes an extra bool indicating whether to copy the base class */
  72         __asm__ __volatile__("pushl $1; pushl %2; call *%0"
  73                              : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
  74     else
  75         __asm__ __volatile__("pushl %2; call *%0"
  76                              : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
  77 }
  78
  79 /* call the destructor of the exception object */
  80 static inline void call_dtor( void *func, void *object )
  81 {
  82     __asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" );
  83 }
  84
  85 /* continue execution to the specified address after exception is caught */
  86 static inline void DECLSPEC_NORETURN continue_after_catch( cxx_exception_frame* frame, void *addr )
  87 {
  88     __asm__ __volatile__("movl -4(%0),%%esp; leal 12(%0),%%ebp; jmp *%1"
  89                          : : "r" (frame), "a" (addr) );
  90     for (;;) ; /* unreached */
  91 }
  92
  93 static inline void dump_type( const cxx_type_info *type )
  94 {
  95     TRACE( "flags %x type %p %s offsets %d,%d,%d size %d copy ctor %p\n",
  96              type->flags, type->type_info, dbgstr_type_info(type->type_info),
  97              type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset,
  98              type->size, type->copy_ctor );
  99 }
 100
 101 static void dump_exception_type( const cxx_exception_type *type )
 102 {
 103     UINT i;
 104
 105     TRACE( "flags %x destr %p handler %p type info %p\n",
 106              type->flags, type->destructor, type->custom_handler, type->type_info_table );
 107     for (i = 0; i < type->type_info_table->count; i++)
 108     {
 109         TRACE( "    %d: ", i );
 110         dump_type( type->type_info_table->info[i] );
 111     }
 112 }
 113
 114 static void dump_function_descr( const cxx_function_descr *descr )
 115 {
 116     UINT i;
 117     int j;
 118
 119     TRACE( "magic %x\n", descr->magic );
 120     TRACE( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count );
 121     for (i = 0; i < descr->unwind_count; i++)
 122     {
 123         TRACE( "    %d: prev %d func %p\n", i,
 124                  descr->unwind_table[i].prev, descr->unwind_table[i].handler );
 125     }
 126     TRACE( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
 127     for (i = 0; i < descr->tryblock_count; i++)
 128     {
 129         TRACE( "    %d: start %d end %d catchlevel %d catch %p %d\n", i,
 130                  descr->tryblock[i].start_level, descr->tryblock[i].end_level,
 131                  descr->tryblock[i].catch_level, descr->tryblock[i].catchblock,
 132                  descr->tryblock[i].catchblock_count );
 133         for (j = 0; j < descr->tryblock[i].catchblock_count; j++)
 134         {
 135             const catchblock_info *ptr = &descr->tryblock[i].catchblock[j];
 136             TRACE( "        %d: flags %x offset %d handler %p type %p %s\n",
 137                      j, ptr->flags, ptr->offset, ptr->handler,
 138                      ptr->type_info, dbgstr_type_info( ptr->type_info ) );
 139         }
 140     }
 141 }
 142
 143 /* check if the exception type is caught by a given catch block, and return the type that matched */
 144 static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type,
 145                                               const catchblock_info *catchblock )
 146 {
 147     UINT i;
 148
 149     for (i = 0; i < exc_type->type_info_table->count; i++)
 150     {
 151         const cxx_type_info *type = exc_type->type_info_table->info[i];
 152
 153         if (!catchblock->type_info) return type;   /* catch(...) matches any type */
 154         if (catchblock->type_info != type->type_info)
 155         {
 156             if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
 157         }
 158         /* type is the same, now check the flags */
 159         if ((exc_type->flags & TYPE_FLAG_CONST) &&
 160             !(catchblock->flags & TYPE_FLAG_CONST)) continue;
 161         if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
 162             !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
 163         return type;  /* it matched */
 164     }
 165     return NULL;
 166 }
 167
 168
 169 /* copy the exception object where the catch block wants it */
 170 static void copy_exception( void *object, cxx_exception_frame *frame,
 171                             const catchblock_info *catchblock, const cxx_type_info *type )
 172 {
 173     void **dest_ptr;
 174
 175     if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
 176     if (!catchblock->offset) return;
 177     dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
 178
 179     if (catchblock->flags & TYPE_FLAG_REFERENCE)
 180     {
 181         *dest_ptr = get_this_pointer( &type->offsets, object );
 182     }
 183     else if (type->flags & CLASS_IS_SIMPLE_TYPE)
 184     {
 185         memmove( dest_ptr, object, type->size );
 186         /* if it is a pointer, adjust it */
 187         if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
 188     }
 189     else  /* copy the object */
 190     {
 191         if (type->copy_ctor)
 192             call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
 193                             (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
 194         else
 195             memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
 196     }
 197 }
 198
 199 /* unwind the local function up to a given trylevel */
 200 static void cxx_local_unwind( cxx_exception_frame* frame, const cxx_function_descr *descr, int last_level)
 201 {
 202     void (*handler)(void);
 203     int trylevel = frame->trylevel;
 204
 205     while (trylevel != last_level)
 206     {
 207         if (trylevel < 0 || trylevel >= descr->unwind_count)
 208         {
 209             ERR( "invalid trylevel %d\n", trylevel );
 210             MSVCRT_terminate();
 211         }
 212         handler = descr->unwind_table[trylevel].handler;
 213         if (handler)
 214         {
 215             TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
 216                    handler, trylevel, last_level, &frame->ebp );
 217             call_ebp_func( handler, &frame->ebp );
 218         }
 219         trylevel = descr->unwind_table[trylevel].prev;
 220     }
 221     frame->trylevel = last_level;
 222 }
 223
 224 /* exception frame for nested exceptions in catch block */
 225 struct catch_func_nested_frame
 226 {
 227     EXCEPTION_REGISTRATION_RECORD frame;     /* standard exception frame */
 228     EXCEPTION_RECORD             *prev_rec;  /* previous record to restore in thread data */
 229     cxx_exception_frame          *cxx_frame; /* frame of parent exception */
 230     const cxx_function_descr     *descr;     /* descriptor of parent exception */
 231     int                           trylevel;  /* current try level */
 232     EXCEPTION_RECORD             *rec;       /* rec associated with frame */
 233 };
 234
 235 /* handler for exceptions happening while calling a catch function */
 236 static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
 237                                             CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
 238 {
 239     struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
 240
 241     if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
 242     {
 243         msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
 244         return ExceptionContinueSearch;
 245     }
 246
 247     TRACE( "got nested exception in catch function\n" );
 248
 249     if(rec->ExceptionCode == CXX_EXCEPTION)
 250     {
 251         PEXCEPTION_RECORD prev_rec = nested_frame->rec;
 252         if(rec->ExceptionInformation[1] == 0 && rec->ExceptionInformation[2] == 0)
 253         {
 254             /* exception was rethrown */
 255             rec->ExceptionInformation[1] = prev_rec->ExceptionInformation[1];
 256             rec->ExceptionInformation[2] = prev_rec->ExceptionInformation[2];
 257             TRACE("detect rethrow: re-propagate: obj: %lx, type: %lx\n",
 258                     rec->ExceptionInformation[1], rec->ExceptionInformation[2]);
 259         }
 260         else {
 261             /* new exception in exception handler, destroy old */
 262             void *object = (void*)prev_rec->ExceptionInformation[1];
 263             cxx_exception_type *info = (cxx_exception_type*) prev_rec->ExceptionInformation[2];
 264             TRACE("detect threw new exception in catch block - destroy old(obj: %p type: %p)\n",
 265                     object, info);
 266             if(info && info->destructor)
 267                 call_dtor( info->destructor, object );
 268         }
 269     }
 270
 271     return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
 272                               NULL, nested_frame->descr, &nested_frame->frame,
 273                               nested_frame->trylevel );
 274 }
 275
 276 /* find and call the appropriate catch block for an exception */
 277 /* returns the address to continue execution to after the catch block was called */
 278 static inline void call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
 279                                      const cxx_function_descr *descr, int nested_trylevel,
 280                                      cxx_exception_type *info )
 281 {
 282     UINT i;
 283     int j;
 284     void *addr, *object = (void *)rec->ExceptionInformation[1];
 285     struct catch_func_nested_frame nested_frame;
 286     int trylevel = frame->trylevel;
 287     thread_data_t *thread_data = msvcrt_get_thread_data();
 288     DWORD save_esp = ((DWORD*)frame)[-1];
 289
 290     for (i = 0; i < descr->tryblock_count; i++)
 291     {
 292         const tryblock_info *tryblock = &descr->tryblock[i];
 293
 294         if (trylevel < tryblock->start_level) continue;
 295         if (trylevel > tryblock->end_level) continue;
 296
 297         /* got a try block */
 298         for (j = 0; j < tryblock->catchblock_count; j++)
 299         {
 300             const catchblock_info *catchblock = &tryblock->catchblock[j];
 301             if(info)
 302             {
 303                 const cxx_type_info *type = find_caught_type( info, catchblock );
 304                 if (!type) continue;
 305
 306                 TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
 307
 308                 /* copy the exception to its destination on the stack */
 309                 copy_exception( object, frame, catchblock, type );
 310             }
 311             else
 312             {
 313                 /* no CXX_EXCEPTION only proceed with a catch(...) block*/
 314                 if(catchblock->type_info)
 315                     continue;
 316                 TRACE("found catch(...) block\n");
 317             }
 318
 319             /* unwind the stack */
 320             RtlUnwind( frame, 0, rec, 0 );
 321             cxx_local_unwind( frame, descr, tryblock->start_level );
 322             frame->trylevel = tryblock->end_level + 1;
 323
 324             /* call the catch block */
 325             TRACE( "calling catch block %p addr %p ebp %p\n",
 326                    catchblock, catchblock->handler, &frame->ebp );
 327
 328             /* setup an exception block for nested exceptions */
 329
 330             nested_frame.frame.Handler = catch_function_nested_handler;
 331             nested_frame.prev_rec  = thread_data->exc_record;
 332             nested_frame.cxx_frame = frame;
 333             nested_frame.descr     = descr;
 334             nested_frame.trylevel  = nested_trylevel + 1;
 335             nested_frame.rec = rec;
 336
 337             __wine_push_frame( &nested_frame.frame );
 338             thread_data->exc_record = rec;
 339             addr = call_ebp_func( catchblock->handler, &frame->ebp );
 340             thread_data->exc_record = nested_frame.prev_rec;
 341             __wine_pop_frame( &nested_frame.frame );
 342
 343             ((DWORD*)frame)[-1] = save_esp;
 344             if (info && info->destructor) call_dtor( info->destructor, object );
 345             TRACE( "done, continuing at %p\n", addr );
 346
 347             continue_after_catch( frame, addr );
 348         }
 349     }
 350 }
 351
 352
 353 /*********************************************************************
 354  *              cxx_frame_handler
 355  *
 356  * Implementation of __CxxFrameHandler.
 357  */
 358 DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
 359                                PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
 360                                const cxx_function_descr *descr,
 361                                EXCEPTION_REGISTRATION_RECORD* nested_frame,
 362                                int nested_trylevel )
 363 {
 364     cxx_exception_type *exc_type;
 365
 366     if (descr->magic != CXX_FRAME_MAGIC)
 367     {
 368         ERR( "invalid frame magic %x\n", descr->magic );
 369         return ExceptionContinueSearch;
 370     }
 371     if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
 372     {
 373         if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
 374         return ExceptionContinueSearch;
 375     }
 376     if (!descr->tryblock_count) return ExceptionContinueSearch;
 377
 378     if(rec->ExceptionCode == CXX_EXCEPTION)
 379     {
 380         exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
 381
 382         if (rec->ExceptionInformation[0] > CXX_FRAME_MAGIC &&
 383                 exc_type->custom_handler)
 384         {
 385             return exc_type->custom_handler( rec, frame, context, dispatch,
 386                                          descr, nested_trylevel, nested_frame, 0 );
 387         }
 388
 389         if (TRACE_ON(seh))
 390         {
 391             TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
 392                   rec, frame, frame->trylevel, descr, nested_frame );
 393             dump_exception_type( exc_type );
 394             dump_function_descr( descr );
 395         }
 396     }
 397     else
 398     {
 399         exc_type = NULL;
 400         TRACE("handling C exception code %x  rec %p frame %p trylevel %d descr %p nested_frame %p\n",
 401               rec->ExceptionCode,  rec, frame, frame->trylevel, descr, nested_frame );
 402     }
 403
 404     call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
 405     return ExceptionContinueSearch;
 406 }
 407
 408
 409 /*********************************************************************
 410  *              __CxxFrameHandler (MSVCRT.@)
 411  */
 412 extern DWORD CDECL __CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
 413                                       PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch );
 414 __ASM_GLOBAL_FUNC( __CxxFrameHandler,
 415                    "pushl $0\n\t"        /* nested_trylevel */
 416                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 417                    "pushl $0\n\t"        /* nested_frame */
 418                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 419                    "pushl %eax\n\t"      /* descr */
 420                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 421                    "pushl 28(%esp)\n\t"  /* dispatch */
 422                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 423                    "pushl 28(%esp)\n\t"  /* context */
 424                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 425                    "pushl 28(%esp)\n\t"  /* frame */
 426                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 427                    "pushl 28(%esp)\n\t"  /* rec */
 428                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 429                    "call " __ASM_NAME("cxx_frame_handler") "\n\t"
 430                    "add $28,%esp\n\t"
 431                    __ASM_CFI(".cfi_adjust_cfa_offset -28\n\t")
 432                    "ret" )
 433
 434
 435 /*********************************************************************
 436  *              __CxxLongjmpUnwind (MSVCRT.@)
 437  *
 438  * Callback meant to be used as UnwindFunc for setjmp/longjmp.
 439  */
 440 void __stdcall __CxxLongjmpUnwind( const struct MSVCRT___JUMP_BUFFER *buf )
 441 {
 442     cxx_exception_frame *frame = (cxx_exception_frame *)buf->Registration;
 443     const cxx_function_descr *descr = (const cxx_function_descr *)buf->UnwindData[0];
 444
 445     TRACE( "unwinding frame %p descr %p trylevel %ld\n", frame, descr, buf->TryLevel );
 446     cxx_local_unwind( frame, descr, buf->TryLevel );
 447 }
 448
 449 #endif  /* __i386__ */
 450
 451
 452 /*********************************************************************
 453  *              __CppXcptFilter (MSVCRT.@)
 454  */
 455 int CDECL __CppXcptFilter(NTSTATUS ex, PEXCEPTION_POINTERS ptr)
 456 {
 457     /* only filter c++ exceptions */
 458     if (ex != CXX_EXCEPTION) return EXCEPTION_CONTINUE_SEARCH;
 459     return _XcptFilter( ex, ptr );
 460 }
 461
 462 /*********************************************************************
 463  *              _CxxThrowException (MSVCRT.@)
 464  */
 465 void CDECL _CxxThrowException( exception *object, const cxx_exception_type *type )
 466 {
 467     ULONG_PTR args[3];
 468
 469     args[0] = CXX_FRAME_MAGIC;
 470     args[1] = (ULONG_PTR)object;
 471     args[2] = (ULONG_PTR)type;
 472     RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
 473 }
 474
 475 /*********************************************************************
 476  *              __CxxDetectRethrow (MSVCRT.@)
 477  */
 478 BOOL CDECL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
 479 {
 480   PEXCEPTION_RECORD rec;
 481
 482   if (!ptrs)
 483     return FALSE;
 484
 485   rec = ptrs->ExceptionRecord;
 486
 487   if (rec->ExceptionCode == CXX_EXCEPTION &&
 488       rec->NumberParameters == 3 &&
 489       rec->ExceptionInformation[0] == CXX_FRAME_MAGIC &&
 490       rec->ExceptionInformation[2])
 491   {
 492     ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
 493     return TRUE;
 494   }
 495   return (msvcrt_get_thread_data()->exc_record == rec);
 496 }
 497
 498 /*********************************************************************
 499  *              __CxxQueryExceptionSize (MSVCRT.@)
 500  */
 501 unsigned int CDECL __CxxQueryExceptionSize(void)
 502 {
 503   return sizeof(cxx_exception_type);
 504 }