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 : "" (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 if (descr->magic <= CXX_FRAME_MAGIC_VC6) return;
142 TRACE( "expect list: %p\n", descr->expect_list );
143 if (descr->magic <= CXX_FRAME_MAGIC_VC7) return;
144 TRACE( "flags: %08x\n", descr->flags );
145 }
146
147 /* check if the exception type is caught by a given catch block, and return the type that matched */
148 static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type,
149 const catchblock_info *catchblock )
150 {
151 UINT i;
152
153 for (i = 0; i < exc_type->type_info_table->count; i++)
154 {
155 const cxx_type_info *type = exc_type->type_info_table->info[i];
156
157 if (!catchblock->type_info) return type; /* catch(...) matches any type */
158 if (catchblock->type_info != type->type_info)
159 {
160 if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
161 }
162 /* type is the same, now check the flags */
163 if ((exc_type->flags & TYPE_FLAG_CONST) &&
164 !(catchblock->flags & TYPE_FLAG_CONST)) continue;
165 if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
166 !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
167 return type; /* it matched */
168 }
169 return NULL;
170 }
171
172
173 /* copy the exception object where the catch block wants it */
174 static void copy_exception( void *object, cxx_exception_frame *frame,
175 const catchblock_info *catchblock, const cxx_type_info *type )
176 {
177 void **dest_ptr;
178
179 if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
180 if (!catchblock->offset) return;
181 dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
182
183 if (catchblock->flags & TYPE_FLAG_REFERENCE)
184 {
185 *dest_ptr = get_this_pointer( &type->offsets, object );
186 }
187 else if (type->flags & CLASS_IS_SIMPLE_TYPE)
188 {
189 memmove( dest_ptr, object, type->size );
190 /* if it is a pointer, adjust it */
191 if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
192 }
193 else /* copy the object */
194 {
195 if (type->copy_ctor)
196 call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
197 (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
198 else
199 memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
200 }
201 }
202
203 /* unwind the local function up to a given trylevel */
204 static void cxx_local_unwind( cxx_exception_frame* frame, const cxx_function_descr *descr, int last_level)
205 {
206 void (*handler)(void);
207 int trylevel = frame->trylevel;
208
209 while (trylevel != last_level)
210 {
211 if (trylevel < 0 || trylevel >= descr->unwind_count)
212 {
213 ERR( "invalid trylevel %d\n", trylevel );
214 MSVCRT_terminate();
215 }
216 handler = descr->unwind_table[trylevel].handler;
217 if (handler)
218 {
219 TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
220 handler, trylevel, last_level, &frame->ebp );
221 call_ebp_func( handler, &frame->ebp );
222 }
223 trylevel = descr->unwind_table[trylevel].prev;
224 }
225 frame->trylevel = last_level;
226 }
227
228 /* exception frame for nested exceptions in catch block */
229 struct catch_func_nested_frame
230 {
231 EXCEPTION_REGISTRATION_RECORD frame; /* standard exception frame */
232 EXCEPTION_RECORD *prev_rec; /* previous record to restore in thread data */
233 cxx_exception_frame *cxx_frame; /* frame of parent exception */
234 const cxx_function_descr *descr; /* descriptor of parent exception */
235 int trylevel; /* current try level */
236 EXCEPTION_RECORD *rec; /* rec associated with frame */
237 };
238
239 /* handler for exceptions happening while calling a catch function */
240 static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
241 CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
242 {
243 struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
244
245 if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
246 {
247 msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
248 return ExceptionContinueSearch;
249 }
250
251 TRACE( "got nested exception in catch function\n" );
252
253 if(rec->ExceptionCode == CXX_EXCEPTION)
254 {
255 PEXCEPTION_RECORD prev_rec = nested_frame->rec;
256 if(rec->ExceptionInformation[1] == 0 && rec->ExceptionInformation[2] == 0)
257 {
258 /* exception was rethrown */
259 rec->ExceptionInformation[1] = prev_rec->ExceptionInformation[1];
260 rec->ExceptionInformation[2] = prev_rec->ExceptionInformation[2];
261 TRACE("detect rethrow: re-propagate: obj: %lx, type: %lx\n",
262 rec->ExceptionInformation[1], rec->ExceptionInformation[2]);
263 }
264 else {
265 /* new exception in exception handler, destroy old */
266 void *object = (void*)prev_rec->ExceptionInformation[1];
267 cxx_exception_type *info = (cxx_exception_type*) prev_rec->ExceptionInformation[2];
268 TRACE("detect threw new exception in catch block - destroy old(obj: %p type: %p)\n",
269 object, info);
270 if(info && info->destructor)
271 call_dtor( info->destructor, object );
272 }
273 }
274
275 return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
276 NULL, nested_frame->descr, &nested_frame->frame,
277 nested_frame->trylevel );
278 }
279
280 /* find and call the appropriate catch block for an exception */
281 /* returns the address to continue execution to after the catch block was called */
282 static inline void call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
283 const cxx_function_descr *descr, int nested_trylevel,
284 cxx_exception_type *info )
285 {
286 UINT i;
287 int j;
288 void *addr, *object = (void *)rec->ExceptionInformation[1];
289 struct catch_func_nested_frame nested_frame;
290 int trylevel = frame->trylevel;
291 thread_data_t *thread_data = msvcrt_get_thread_data();
292 DWORD save_esp = ((DWORD*)frame)[-1];
293
294 for (i = 0; i < descr->tryblock_count; i++)
295 {
296 const tryblock_info *tryblock = &descr->tryblock[i];
297
298 if (trylevel < tryblock->start_level) continue;
299 if (trylevel > tryblock->end_level) continue;
300
301 /* got a try block */
302 for (j = 0; j < tryblock->catchblock_count; j++)
303 {
304 const catchblock_info *catchblock = &tryblock->catchblock[j];
305 if(info)
306 {
307 const cxx_type_info *type = find_caught_type( info, catchblock );
308 if (!type) continue;
309
310 TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
311
312 /* copy the exception to its destination on the stack */
313 copy_exception( object, frame, catchblock, type );
314 }
315 else
316 {
317 /* no CXX_EXCEPTION only proceed with a catch(...) block*/
318 if(catchblock->type_info)
319 continue;
320 TRACE("found catch(...) block\n");
321 }
322
323 /* unwind the stack */
324 RtlUnwind( frame, 0, rec, 0 );
325 cxx_local_unwind( frame, descr, tryblock->start_level );
326 frame->trylevel = tryblock->end_level + 1;
327
328 /* call the catch block */
329 TRACE( "calling catch block %p addr %p ebp %p\n",
330 catchblock, catchblock->handler, &frame->ebp );
331
332 /* setup an exception block for nested exceptions */
333
334 nested_frame.frame.Handler = catch_function_nested_handler;
335 nested_frame.prev_rec = thread_data->exc_record;
336 nested_frame.cxx_frame = frame;
337 nested_frame.descr = descr;
338 nested_frame.trylevel = nested_trylevel + 1;
339 nested_frame.rec = rec;
340
341 __wine_push_frame( &nested_frame.frame );
342 thread_data->exc_record = rec;
343 addr = call_ebp_func( catchblock->handler, &frame->ebp );
344 thread_data->exc_record = nested_frame.prev_rec;
345 __wine_pop_frame( &nested_frame.frame );
346
347 ((DWORD*)frame)[-1] = save_esp;
348 if (info && info->destructor) call_dtor( info->destructor, object );
349 TRACE( "done, continuing at %p\n", addr );
350
351 continue_after_catch( frame, addr );
352 }
353 }
354 }
355
356
357 /*********************************************************************
358 * cxx_frame_handler
359 *
360 * Implementation of __CxxFrameHandler.
361 */
362 DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
363 PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
364 const cxx_function_descr *descr,
365 EXCEPTION_REGISTRATION_RECORD* nested_frame,
366 int nested_trylevel )
367 {
368 cxx_exception_type *exc_type;
369
370 if (descr->magic < CXX_FRAME_MAGIC_VC6 || descr->magic > CXX_FRAME_MAGIC_VC8)
371 {
372 ERR( "invalid frame magic %x\n", descr->magic );
373 return ExceptionContinueSearch;
374 }
375 if (descr->magic >= CXX_FRAME_MAGIC_VC8 &&
376 (descr->flags & FUNC_DESCR_SYNCHRONOUS) &&
377 (rec->ExceptionCode != CXX_EXCEPTION))
378 return ExceptionContinueSearch; /* handle only c++ exceptions */
379
380 if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
381 {
382 if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
383 return ExceptionContinueSearch;
384 }
385 if (!descr->tryblock_count) return ExceptionContinueSearch;
386
387 if(rec->ExceptionCode == CXX_EXCEPTION)
388 {
389 exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
390
391 if (rec->ExceptionInformation[0] > CXX_FRAME_MAGIC_VC8 &&
392 exc_type->custom_handler)
393 {
394 return exc_type->custom_handler( rec, frame, context, dispatch,
395 descr, nested_trylevel, nested_frame, 0 );
396 }
397
398 if (TRACE_ON(seh))
399 {
400 TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
401 rec, frame, frame->trylevel, descr, nested_frame );
402 dump_exception_type( exc_type );
403 dump_function_descr( descr );
404 }
405 }
406 else
407 {
408 exc_type = NULL;
409 TRACE("handling C exception code %x rec %p frame %p trylevel %d descr %p nested_frame %p\n",
410 rec->ExceptionCode, rec, frame, frame->trylevel, descr, nested_frame );
411 }
412
413 call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
414 return ExceptionContinueSearch;
415 }
416
417
418 /*********************************************************************
419 * __CxxFrameHandler (MSVCRT.@)
420 */
421 extern DWORD CDECL __CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
422 PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch );
423 __ASM_GLOBAL_FUNC( __CxxFrameHandler,
424 "pushl $0\n\t" /* nested_trylevel */
425 __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
426 "pushl $0\n\t" /* nested_frame */
427 __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
428 "pushl %eax\n\t" /* descr */
429 __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
430 "pushl 28(%esp)\n\t" /* dispatch */
431 __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
432 "pushl 28(%esp)\n\t" /* context */
433 __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
434 "pushl 28(%esp)\n\t" /* frame */
435 __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
436 "pushl 28(%esp)\n\t" /* rec */
437 __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
438 "call " __ASM_NAME("cxx_frame_handler") "\n\t"
439 "add $28,%esp\n\t"
440 __ASM_CFI(".cfi_adjust_cfa_offset -28\n\t")
441 "ret" )
442
443
444 /*********************************************************************
445 * __CxxLongjmpUnwind (MSVCRT.@)
446 *
447 * Callback meant to be used as UnwindFunc for setjmp/longjmp.
448 */
449 void __stdcall __CxxLongjmpUnwind( const struct MSVCRT___JUMP_BUFFER *buf )
450 {
451 cxx_exception_frame *frame = (cxx_exception_frame *)buf->Registration;
452 const cxx_function_descr *descr = (const cxx_function_descr *)buf->UnwindData[0];
453
454 TRACE( "unwinding frame %p descr %p trylevel %ld\n", frame, descr, buf->TryLevel );
455 cxx_local_unwind( frame, descr, buf->TryLevel );
456 }
457
458 #endif /* __i386__ */
459
460
461 /*********************************************************************
462 * __CppXcptFilter (MSVCRT.@)
463 */
464 int CDECL __CppXcptFilter(NTSTATUS ex, PEXCEPTION_POINTERS ptr)
465 {
466 /* only filter c++ exceptions */
467 if (ex != CXX_EXCEPTION) return EXCEPTION_CONTINUE_SEARCH;
468 return _XcptFilter( ex, ptr );
469 }
470
471 /*********************************************************************
472 * _CxxThrowException (MSVCRT.@)
473 */
474 void WINAPI _CxxThrowException( exception *object, const cxx_exception_type *type )
475 {
476 ULONG_PTR args[3];
477
478 args[0] = CXX_FRAME_MAGIC_VC6;
479 args[1] = (ULONG_PTR)object;
480 args[2] = (ULONG_PTR)type;
481 RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
482 }
483
484 /*********************************************************************
485 * __CxxDetectRethrow (MSVCRT.@)
486 */
487 BOOL CDECL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
488 {
489 PEXCEPTION_RECORD rec;
490
491 if (!ptrs)
492 return FALSE;
493
494 rec = ptrs->ExceptionRecord;
495
496 if (rec->ExceptionCode == CXX_EXCEPTION &&
497 rec->NumberParameters == 3 &&
498 rec->ExceptionInformation[0] == CXX_FRAME_MAGIC_VC6 &&
499 rec->ExceptionInformation[2])
500 {
501 ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
502 return TRUE;
503 }
504 return (msvcrt_get_thread_data()->exc_record == rec);
505 }
506
507 /*********************************************************************
508 * __CxxQueryExceptionSize (MSVCRT.@)
509 */
510 unsigned int CDECL __CxxQueryExceptionSize(void)
511 {
512 return sizeof(cxx_exception_type);
513 }
514
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