dlls/msvcrt/except.c

   1 /*
   2  * msvcrt.dll exception handling
   3  *
   4  * Copyright 2000 Jon Griffiths
   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  * NOTES:
  21  *
  22  * See http://www.microsoft.com/msj/0197/exception/exception.htm,
  23  * but don't believe all of it.
  24  *
  25  * FIXME: Incomplete support for nested exceptions/try block cleanup.
  26  */
  27 #include "config.h"
  28
  29 #include "ntddk.h"
  30 #include "wine/exception.h"
  31 #include "thread.h"
  32 #include "msvcrt.h"
  33
  34 #include "msvcrt/setjmp.h"
  35 #include "msvcrt/excpt.h"
  36
  37
  38 #include "wine/debug.h"
  39
  40 WINE_DEFAULT_DEBUG_CHANNEL(msvcrt);
  41
  42 typedef void (*MSVCRT_sig_handler_func)(void);
  43
  44 /* VC++ extensions to Win32 SEH */
  45 typedef struct _SCOPETABLE
  46 {
  47   DWORD previousTryLevel;
  48   int (*lpfnFilter)(PEXCEPTION_POINTERS);
  49   int (*lpfnHandler)(void);
  50 } SCOPETABLE, *PSCOPETABLE;
  51
  52 typedef struct _MSVCRT_EXCEPTION_FRAME
  53 {
  54   EXCEPTION_FRAME *prev;
  55   void (*handler)(PEXCEPTION_RECORD, PEXCEPTION_FRAME,
  56                   PCONTEXT, PEXCEPTION_RECORD);
  57   PSCOPETABLE scopetable;
  58   DWORD trylevel;
  59   int _ebp;
  60   PEXCEPTION_POINTERS xpointers;
  61 } MSVCRT_EXCEPTION_FRAME;
  62
  63 #define TRYLEVEL_END 0xffffffff /* End of trylevel list */
  64
  65 #if defined(__GNUC__) && defined(__i386__)
  66
  67 inline static void call_finally_block( void *code_block, void *base_ptr )
  68 {
  69     __asm__ __volatile__ ("movl %1,%%ebp; call *%%eax" \
  70                           : : "a" (code_block), "g" (base_ptr));
  71 }
  72
  73 static DWORD MSVCRT_nested_handler(PEXCEPTION_RECORD rec,
  74                                    struct __EXCEPTION_FRAME* frame,
  75                                    PCONTEXT context WINE_UNUSED,
  76                                    struct __EXCEPTION_FRAME** dispatch)
  77 {
  78   if (rec->ExceptionFlags & 0x6)
  79     return ExceptionContinueSearch;
  80   *dispatch = frame;
  81   return ExceptionCollidedUnwind;
  82 }
  83 #endif
  84
  85
  86 /*********************************************************************
  87  *              _XcptFilter (MSVCRT.@)
  88  */
  89 int _XcptFilter(int ex, PEXCEPTION_POINTERS ptr)
  90 {
  91   FIXME("(%d,%p)semi-stub\n", ex, ptr);
  92   return UnhandledExceptionFilter(ptr);
  93 }
  94
  95 /*********************************************************************
  96  *              _EH_prolog (MSVCRT.@)
  97  */
  98 #ifdef __i386__
  99 /* Provided for VC++ binary compatability only */
 100 __ASM_GLOBAL_FUNC(_EH_prolog,
 101                   "pushl $0xff\n\t"
 102                   "pushl %eax\n\t"
 103                   "pushl %fs:0\n\t"
 104                   "movl  %esp, %fs:0\n\t"
 105                   "movl  12(%esp), %eax\n\t"
 106                   "movl  %ebp, 12(%esp)\n\t"
 107                   "leal  12(%esp), %ebp\n\t"
 108                   "pushl %eax\n\t"
 109                   "ret");
 110 #endif
 111
 112 /*******************************************************************
 113  *              _global_unwind2 (MSVCRT.@)
 114  */
 115 void _global_unwind2(PEXCEPTION_FRAME frame)
 116 {
 117     TRACE("(%p)\n",frame);
 118     RtlUnwind( frame, 0, 0, 0 );
 119 }
 120
 121 /*******************************************************************
 122  *              _local_unwind2 (MSVCRT.@)
 123  */
 124 void _local_unwind2(MSVCRT_EXCEPTION_FRAME* frame,
 125                     DWORD trylevel)
 126 {
 127   MSVCRT_EXCEPTION_FRAME *curframe = frame;
 128   DWORD curtrylevel = 0xfe;
 129   EXCEPTION_FRAME reg;
 130
 131   TRACE("(%p,%ld,%ld)\n",frame, frame->trylevel, trylevel);
 132
 133   /* Register a handler in case of a nested exception */
 134   reg.Handler = (PEXCEPTION_HANDLER)MSVCRT_nested_handler;
 135   reg.Prev = NtCurrentTeb()->except;
 136   __wine_push_frame(&reg);
 137
 138   while (frame->trylevel != TRYLEVEL_END && frame->trylevel != trylevel)
 139   {
 140     curtrylevel = frame->scopetable[frame->trylevel].previousTryLevel;
 141     curframe = frame;
 142     curframe->trylevel = curtrylevel;
 143     if (!frame->scopetable[curtrylevel].lpfnFilter)
 144     {
 145       ERR("__try block cleanup not implemented - expect crash!\n");
 146       /* FIXME: Remove current frame, set ebp, call
 147        * frame->scopetable[curtrylevel].lpfnHandler()
 148        */
 149     }
 150   }
 151   __wine_pop_frame(&reg);
 152   TRACE("unwound OK\n");
 153 }
 154
 155 /*********************************************************************
 156  *              _except_handler2 (MSVCRT.@)
 157  */
 158 int _except_handler2(PEXCEPTION_RECORD rec,
 159                      PEXCEPTION_FRAME frame,
 160                      PCONTEXT context,
 161                      PEXCEPTION_FRAME* dispatcher)
 162 {
 163   FIXME("exception %lx flags=%lx at %p handler=%p %p %p stub\n",
 164         rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,
 165         frame->Handler, context, dispatcher);
 166   return ExceptionContinueSearch;
 167 }
 168
 169 /*********************************************************************
 170  *              _except_handler3 (MSVCRT.@)
 171  */
 172 int _except_handler3(PEXCEPTION_RECORD rec,
 173                      MSVCRT_EXCEPTION_FRAME* frame,
 174                      PCONTEXT context, void* dispatcher)
 175 {
 176 #if defined(__GNUC__) && defined(__i386__)
 177   long retval, trylevel;
 178   EXCEPTION_POINTERS exceptPtrs;
 179   PSCOPETABLE pScopeTable;
 180
 181   TRACE("exception %lx flags=%lx at %p handler=%p %p %p semi-stub\n",
 182         rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,
 183         frame->handler, context, dispatcher);
 184
 185   __asm__ __volatile__ ("cld");
 186
 187   if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
 188   {
 189     /* Unwinding the current frame */
 190      _local_unwind2(frame, TRYLEVEL_END);
 191     return ExceptionContinueSearch;
 192   }
 193   else
 194   {
 195     /* Hunting for handler */
 196     exceptPtrs.ExceptionRecord = rec;
 197     exceptPtrs.ContextRecord = context;
 198     *((DWORD *)frame-1) = (DWORD)&exceptPtrs;
 199     trylevel = frame->trylevel;
 200     pScopeTable = frame->scopetable;
 201
 202     while (trylevel != TRYLEVEL_END)
 203     {
 204       if (pScopeTable[trylevel].lpfnFilter)
 205       {
 206         TRACE("filter = %p\n", pScopeTable[trylevel].lpfnFilter);
 207
 208         retval = pScopeTable[trylevel].lpfnFilter(&exceptPtrs);
 209
 210         TRACE("filter returned %s\n", retval == EXCEPTION_CONTINUE_EXECUTION ?
 211               "CONTINUE_EXECUTION" : retval == EXCEPTION_EXECUTE_HANDLER ?
 212               "EXECUTE_HANDLER" : "CONTINUE_SEARCH");
 213
 214         if (retval == EXCEPTION_CONTINUE_EXECUTION)
 215           return ExceptionContinueExecution;
 216
 217         if (retval == EXCEPTION_EXECUTE_HANDLER)
 218         {
 219           /* Unwind all higher frames, this one will handle the exception */
 220           _global_unwind2((PEXCEPTION_FRAME)frame);
 221           _local_unwind2(frame, trylevel);
 222
 223           /* Set our trylevel to the enclosing block, and call the __finally
 224            * code, which won't return
 225            */
 226           frame->trylevel = pScopeTable->previousTryLevel;
 227           TRACE("__finally block %p\n",pScopeTable[trylevel].lpfnHandler);
 228           call_finally_block(pScopeTable[trylevel].lpfnHandler, &frame->_ebp);
 229           ERR("Returned from __finally block - expect crash!\n");
 230        }
 231       }
 232       trylevel = pScopeTable->previousTryLevel;
 233     }
 234   }
 235 #else
 236   TRACE("exception %lx flags=%lx at %p handler=%p %p %p stub\n",
 237         rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,
 238         frame->handler, context, dispatcher);
 239 #endif
 240   return ExceptionContinueSearch;
 241 }
 242
 243 /*********************************************************************
 244  *              _abnormal_termination (MSVCRT.@)
 245  */
 246 int _abnormal_termination(void)
 247 {
 248   FIXME("(void)stub\n");
 249   return 0;
 250 }
 251
 252 /*
 253  * setjmp/longjmp implementation
 254  */
 255
 256 #ifdef __i386__
 257 #define MSVCRT_JMP_MAGIC 0x56433230 /* ID value for new jump structure */
 258 typedef void (*MSVCRT_unwind_function)(const void*);
 259
 260 /*
 261  * The signatures of the setjmp/longjmp functions do not match that
 262  * declared in the setjmp header so they don't follow the regular naming
 263  * convention to avoid conflicts.
 264  */
 265
 266 /*******************************************************************
 267  *              _setjmp (MSVCRT.@)
 268  */
 269 void _MSVCRT__setjmp(_JUMP_BUFFER *jmp, CONTEXT86* context)
 270 {
 271     TRACE("(%p)\n",jmp);
 272     jmp->Ebp = context->Ebp;
 273     jmp->Ebx = context->Ebx;
 274     jmp->Edi = context->Edi;
 275     jmp->Esi = context->Esi;
 276     jmp->Esp = context->Esp;
 277     jmp->Eip = context->Eip;
 278     jmp->Registration = (unsigned long)NtCurrentTeb()->except;
 279     if (jmp->Registration == TRYLEVEL_END)
 280         jmp->TryLevel = TRYLEVEL_END;
 281     else
 282         jmp->TryLevel = ((MSVCRT_EXCEPTION_FRAME*)jmp->Registration)->trylevel;
 283     TRACE("returning 0\n");
 284     context->Eax=0;
 285 }
 286
 287 /*******************************************************************
 288  *              _setjmp3 (MSVCRT.@)
 289  */
 290 void _MSVCRT__setjmp3(_JUMP_BUFFER *jmp, int nb_args, CONTEXT86* context)
 291 {
 292     TRACE("(%p,%d)\n",jmp,nb_args);
 293     jmp->Ebp = context->Ebp;
 294     jmp->Ebx = context->Ebx;
 295     jmp->Edi = context->Edi;
 296     jmp->Esi = context->Esi;
 297     jmp->Esp = context->Esp;
 298     jmp->Eip = context->Eip;
 299     jmp->Cookie = MSVCRT_JMP_MAGIC;
 300     jmp->UnwindFunc = 0;
 301     jmp->Registration = (unsigned long)NtCurrentTeb()->except;
 302     if (jmp->Registration == TRYLEVEL_END)
 303     {
 304         jmp->TryLevel = TRYLEVEL_END;
 305     }
 306     else
 307     {
 308         void **args = ((void**)context->Esp)+2;
 309
 310         if (nb_args > 0) jmp->UnwindFunc = (unsigned long)*args++;
 311         if (nb_args > 1) jmp->TryLevel = (unsigned long)*args++;
 312         else jmp->TryLevel = ((MSVCRT_EXCEPTION_FRAME*)jmp->Registration)->trylevel;
 313         if (nb_args > 2)
 314         {
 315             size_t size = (nb_args - 2) * sizeof(DWORD);
 316             memcpy( jmp->UnwindData, args, min( size, sizeof(jmp->UnwindData) ));
 317         }
 318     }
 319     TRACE("returning 0\n");
 320     context->Eax = 0;
 321 }
 322
 323 /*********************************************************************
 324  *              longjmp (MSVCRT.@)
 325  */
 326 void _MSVCRT_longjmp(_JUMP_BUFFER *jmp, int retval, CONTEXT86* context)
 327 {
 328     unsigned long cur_frame = 0;
 329
 330     TRACE("(%p,%d)\n", jmp, retval);
 331
 332     cur_frame=(unsigned long)NtCurrentTeb()->except;
 333     TRACE("cur_frame=%lx\n",cur_frame);
 334
 335     if (cur_frame != jmp->Registration)
 336         _global_unwind2((PEXCEPTION_FRAME)jmp->Registration);
 337
 338     if (jmp->Registration)
 339     {
 340         if (!IsBadReadPtr(&jmp->Cookie, sizeof(long)) &&
 341             jmp->Cookie == MSVCRT_JMP_MAGIC && jmp->UnwindFunc)
 342         {
 343             MSVCRT_unwind_function unwind_func;
 344
 345             unwind_func=(MSVCRT_unwind_function)jmp->UnwindFunc;
 346             unwind_func(jmp);
 347         }
 348         else
 349             _local_unwind2((MSVCRT_EXCEPTION_FRAME*)jmp->Registration,
 350                            jmp->TryLevel);
 351     }
 352
 353     if (!retval)
 354         retval = 1;
 355
 356     TRACE("Jump to %lx returning %d\n",jmp->Eip,retval);
 357     context->Ebp = jmp->Ebp;
 358     context->Ebx = jmp->Ebx;
 359     context->Edi = jmp->Edi;
 360     context->Esi = jmp->Esi;
 361     context->Esp = jmp->Esp;
 362     context->Eip = jmp->Eip;
 363     context->Eax = retval;
 364 }
 365 #endif /* i386 */
 366
 367 /*********************************************************************
 368  *              signal (MSVCRT.@)
 369  */
 370 void* MSVCRT_signal(int sig, MSVCRT_sig_handler_func func)
 371 {
 372   FIXME("(%d %p):stub\n", sig, func);
 373   return (void*)-1;
 374 }
 375
 376 /*********************************************************************
 377  *              __CxxFrameHandler (MSVCRT.@)
 378  */
 379 DWORD __CxxFrameHandler(PEXCEPTION_RECORD rec, struct __EXCEPTION_FRAME* frame,
 380                         PCONTEXT context, struct __EXCEPTION_FRAME** dispatch)
 381 {
 382     FIXME("(%p,%p,%p,%p):stub?\n",rec,frame,context,dispatch);
 383
 384     /* Copied from MSVCRT_nested_handler, I hope this is more
 385      * or less the right thing to do
 386      */
 387     if (rec->ExceptionFlags & 0x6)
 388         return ExceptionContinueSearch;
 389     *dispatch = frame;
 390     return ExceptionCollidedUnwind;
 391 }