/* * msvcrt C++ exception handling * * Copyright 2002 Alexandre Julliard * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA * * NOTES * A good reference is the article "How a C++ compiler implements * exception handling" by Vishal Kochhar, available on * www.thecodeproject.com. */ #include "config.h" #include "wine/port.h" #include <stdarg.h> #include "windef.h" #include "winbase.h" #include "winreg.h" #include "winternl.h" #include "msvcrt.h" #include "wine/exception.h" #include "excpt.h" #include "wine/debug.h" #include "cppexcept.h" #ifdef __i386__ /* CxxFrameHandler is not supported on non-i386 */ WINE_DEFAULT_DEBUG_CHANNEL(seh); DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame, PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch, const cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame, int nested_trylevel ); /* call a function with a given ebp */ static inline void *call_ebp_func( void *func, void *ebp ) { void *ret; int dummy; __asm__ __volatile__ ("pushl %%ebx\n\t" "pushl %%ebp\n\t" "movl %4,%%ebp\n\t" "call *%%eax\n\t" "popl %%ebp\n\t" "popl %%ebx" : "=a" (ret), "=S" (dummy), "=D" (dummy) : "0" (func), "1" (ebp) : "ecx", "edx", "memory" ); return ret; } /* call a copy constructor */ static inline void call_copy_ctor( void *func, void *this, void *src, int has_vbase ) { TRACE( "calling copy ctor %p object %p src %p\n", func, this, src ); if (has_vbase) /* in that case copy ctor takes an extra bool indicating whether to copy the base class */ __asm__ __volatile__("pushl $1; pushl %2; call *%0" : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" ); else __asm__ __volatile__("pushl %2; call *%0" : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" ); } /* call the destructor of the exception object */ static inline void call_dtor( void *func, void *object ) { __asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" ); } /* continue execution to the specified address after exception is caught */ static inline void DECLSPEC_NORETURN continue_after_catch( cxx_exception_frame* frame, void *addr ) { __asm__ __volatile__("movl -4(%0),%%esp; leal 12(%0),%%ebp; jmp *%1" : : "r" (frame), "a" (addr) ); for (;;) ; /* unreached */ } static inline void dump_type( const cxx_type_info *type ) { TRACE( "flags %x type %p %s offsets %d,%d,%d size %d copy ctor %p\n", type->flags, type->type_info, dbgstr_type_info(type->type_info), type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset, type->size, type->copy_ctor ); } static void dump_exception_type( const cxx_exception_type *type ) { UINT i; TRACE( "flags %x destr %p handler %p type info %p\n", type->flags, type->destructor, type->custom_handler, type->type_info_table ); for (i = 0; i < type->type_info_table->count; i++) { TRACE( " %d: ", i ); dump_type( type->type_info_table->info[i] ); } } static void dump_function_descr( const cxx_function_descr *descr ) { UINT i; int j; TRACE( "magic %x\n", descr->magic ); TRACE( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count ); for (i = 0; i < descr->unwind_count; i++) { TRACE( " %d: prev %d func %p\n", i, descr->unwind_table[i].prev, descr->unwind_table[i].handler ); } TRACE( "try table: %p %d\n", descr->tryblock, descr->tryblock_count ); for (i = 0; i < descr->tryblock_count; i++) { TRACE( " %d: start %d end %d catchlevel %d catch %p %d\n", i, descr->tryblock[i].start_level, descr->tryblock[i].end_level, descr->tryblock[i].catch_level, descr->tryblock[i].catchblock, descr->tryblock[i].catchblock_count ); for (j = 0; j < descr->tryblock[i].catchblock_count; j++) { const catchblock_info *ptr = &descr->tryblock[i].catchblock[j]; TRACE( " %d: flags %x offset %d handler %p type %p %s\n", j, ptr->flags, ptr->offset, ptr->handler, ptr->type_info, dbgstr_type_info( ptr->type_info ) ); } } } /* check if the exception type is caught by a given catch block, and return the type that matched */ static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type, const catchblock_info *catchblock ) { UINT i; for (i = 0; i < exc_type->type_info_table->count; i++) { const cxx_type_info *type = exc_type->type_info_table->info[i]; if (!catchblock->type_info) return type; /* catch(...) matches any type */ if (catchblock->type_info != type->type_info) { if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue; } /* type is the same, now check the flags */ if ((exc_type->flags & TYPE_FLAG_CONST) && !(catchblock->flags & TYPE_FLAG_CONST)) continue; if ((exc_type->flags & TYPE_FLAG_VOLATILE) && !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue; return type; /* it matched */ } return NULL; } /* copy the exception object where the catch block wants it */ static void copy_exception( void *object, cxx_exception_frame *frame, const catchblock_info *catchblock, const cxx_type_info *type ) { void **dest_ptr; if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return; if (!catchblock->offset) return; dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset); if (catchblock->flags & TYPE_FLAG_REFERENCE) { *dest_ptr = get_this_pointer( &type->offsets, object ); } else if (type->flags & CLASS_IS_SIMPLE_TYPE) { memmove( dest_ptr, object, type->size ); /* if it is a pointer, adjust it */ if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr ); } else /* copy the object */ { if (type->copy_ctor) call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object), (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) ); else memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size ); } } /* unwind the local function up to a given trylevel */ static void cxx_local_unwind( cxx_exception_frame* frame, const cxx_function_descr *descr, int last_level) { void (*handler)(); int trylevel = frame->trylevel; while (trylevel != last_level) { if (trylevel < 0 || trylevel >= descr->unwind_count) { ERR( "invalid trylevel %d\n", trylevel ); MSVCRT_terminate(); } handler = descr->unwind_table[trylevel].handler; if (handler) { TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n", handler, trylevel, last_level, &frame->ebp ); call_ebp_func( handler, &frame->ebp ); } trylevel = descr->unwind_table[trylevel].prev; } frame->trylevel = last_level; } /* exception frame for nested exceptions in catch block */ struct catch_func_nested_frame { EXCEPTION_REGISTRATION_RECORD frame; /* standard exception frame */ EXCEPTION_RECORD *prev_rec; /* previous record to restore in thread data */ cxx_exception_frame *cxx_frame; /* frame of parent exception */ const cxx_function_descr *descr; /* descriptor of parent exception */ int trylevel; /* current try level */ EXCEPTION_RECORD *rec; /* rec associated with frame */ }; /* handler for exceptions happening while calling a catch function */ static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame, CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher ) { struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame; if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)) { msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec; return ExceptionContinueSearch; } TRACE( "got nested exception in catch function\n" ); if(rec->ExceptionCode == CXX_EXCEPTION) { PEXCEPTION_RECORD prev_rec = nested_frame->rec; if(rec->ExceptionInformation[1] == 0 && rec->ExceptionInformation[2] == 0) { /* exception was rethrown */ rec->ExceptionInformation[1] = prev_rec->ExceptionInformation[1]; rec->ExceptionInformation[2] = prev_rec->ExceptionInformation[2]; TRACE("detect rethrow: re-propagate: obj: %lx, type: %lx\n", rec->ExceptionInformation[1], rec->ExceptionInformation[2]); } else { /* new exception in exception handler, destroy old */ void *object = (void*)prev_rec->ExceptionInformation[1]; cxx_exception_type *info = (cxx_exception_type*) prev_rec->ExceptionInformation[2]; TRACE("detect threw new exception in catch block - destroy old(obj: %p type: %p)\n", object, info); if(info && info->destructor) call_dtor( info->destructor, object ); } } return cxx_frame_handler( rec, nested_frame->cxx_frame, context, NULL, nested_frame->descr, &nested_frame->frame, nested_frame->trylevel ); } /* find and call the appropriate catch block for an exception */ /* returns the address to continue execution to after the catch block was called */ static inline void call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame, const cxx_function_descr *descr, int nested_trylevel, cxx_exception_type *info ) { UINT i; int j; void *addr, *object = (void *)rec->ExceptionInformation[1]; struct catch_func_nested_frame nested_frame; int trylevel = frame->trylevel; thread_data_t *thread_data = msvcrt_get_thread_data(); DWORD save_esp = ((DWORD*)frame)[-1]; for (i = 0; i < descr->tryblock_count; i++) { const tryblock_info *tryblock = &descr->tryblock[i]; if (trylevel < tryblock->start_level) continue; if (trylevel > tryblock->end_level) continue; /* got a try block */ for (j = 0; j < tryblock->catchblock_count; j++) { const catchblock_info *catchblock = &tryblock->catchblock[j]; if(info) { const cxx_type_info *type = find_caught_type( info, catchblock ); if (!type) continue; TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j ); /* copy the exception to its destination on the stack */ copy_exception( object, frame, catchblock, type ); } else { /* no CXX_EXCEPTION only proceed with a catch(...) block*/ if(catchblock->type_info) continue; TRACE("found catch(...) block\n"); } /* unwind the stack */ RtlUnwind( frame, 0, rec, 0 ); cxx_local_unwind( frame, descr, tryblock->start_level ); frame->trylevel = tryblock->end_level + 1; /* call the catch block */ TRACE( "calling catch block %p addr %p ebp %p\n", catchblock, catchblock->handler, &frame->ebp ); /* setup an exception block for nested exceptions */ nested_frame.frame.Handler = catch_function_nested_handler; nested_frame.prev_rec = thread_data->exc_record; nested_frame.cxx_frame = frame; nested_frame.descr = descr; nested_frame.trylevel = nested_trylevel + 1; nested_frame.rec = rec; __wine_push_frame( &nested_frame.frame ); thread_data->exc_record = rec; addr = call_ebp_func( catchblock->handler, &frame->ebp ); thread_data->exc_record = nested_frame.prev_rec; __wine_pop_frame( &nested_frame.frame ); ((DWORD*)frame)[-1] = save_esp; if (info && info->destructor) call_dtor( info->destructor, object ); TRACE( "done, continuing at %p\n", addr ); continue_after_catch( frame, addr ); } } } /********************************************************************* * cxx_frame_handler * * Implementation of __CxxFrameHandler. */ DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame, PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch, const cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame, int nested_trylevel ) { cxx_exception_type *exc_type; if (descr->magic != CXX_FRAME_MAGIC) { ERR( "invalid frame magic %x\n", descr->magic ); return ExceptionContinueSearch; } if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND)) { if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 ); return ExceptionContinueSearch; } if (!descr->tryblock_count) return ExceptionContinueSearch; if(rec->ExceptionCode == CXX_EXCEPTION) { exc_type = (cxx_exception_type *)rec->ExceptionInformation[2]; if (rec->ExceptionInformation[0] > CXX_FRAME_MAGIC && exc_type->custom_handler) { return exc_type->custom_handler( rec, frame, context, dispatch, descr, nested_trylevel, nested_frame, 0 ); } if (TRACE_ON(seh)) { TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n", rec, frame, frame->trylevel, descr, nested_frame ); dump_exception_type( exc_type ); dump_function_descr( descr ); } } else { exc_type = NULL; TRACE("handling C exception code %x rec %p frame %p trylevel %d descr %p nested_frame %p\n", rec->ExceptionCode, rec, frame, frame->trylevel, descr, nested_frame ); } call_catch_block( rec, frame, descr, frame->trylevel, exc_type ); return ExceptionContinueSearch; } /********************************************************************* * __CxxFrameHandler (MSVCRT.@) */ extern DWORD CDECL __CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame, PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch ); __ASM_GLOBAL_FUNC( __CxxFrameHandler, "pushl $0\n\t" /* nested_trylevel */ "pushl $0\n\t" /* nested_frame */ "pushl %eax\n\t" /* descr */ "pushl 28(%esp)\n\t" /* dispatch */ "pushl 28(%esp)\n\t" /* context */ "pushl 28(%esp)\n\t" /* frame */ "pushl 28(%esp)\n\t" /* rec */ "call " __ASM_NAME("cxx_frame_handler") "\n\t" "add $28,%esp\n\t" "ret" ) /********************************************************************* * __CxxLongjmpUnwind (MSVCRT.@) * * Callback meant to be used as UnwindFunc for setjmp/longjmp. */ void __stdcall __CxxLongjmpUnwind( const struct MSVCRT___JUMP_BUFFER *buf ) { cxx_exception_frame *frame = (cxx_exception_frame *)buf->Registration; const cxx_function_descr *descr = (const cxx_function_descr *)buf->UnwindData[0]; TRACE( "unwinding frame %p descr %p trylevel %ld\n", frame, descr, buf->TryLevel ); cxx_local_unwind( frame, descr, buf->TryLevel ); } #endif /* __i386__ */ /********************************************************************* * _CxxThrowException (MSVCRT.@) */ void CDECL _CxxThrowException( exception *object, const cxx_exception_type *type ) { ULONG_PTR args[3]; args[0] = CXX_FRAME_MAGIC; args[1] = (ULONG_PTR)object; args[2] = (ULONG_PTR)type; RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args ); } /********************************************************************* * __CxxDetectRethrow (MSVCRT.@) */ BOOL CDECL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs) { PEXCEPTION_RECORD rec; if (!ptrs) return FALSE; rec = ptrs->ExceptionRecord; if (rec->ExceptionCode == CXX_EXCEPTION && rec->NumberParameters == 3 && rec->ExceptionInformation[0] == CXX_FRAME_MAGIC && rec->ExceptionInformation[2]) { ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record; return TRUE; } return (msvcrt_get_thread_data()->exc_record == rec); } /********************************************************************* * __CxxQueryExceptionSize (MSVCRT.@) */ unsigned int CDECL __CxxQueryExceptionSize(void) { return sizeof(cxx_exception_type); }