dlls/msvcrt/except.c

   1 /*
   2  * msvcrt.dll exception handling
   3  *
   4  * Copyright 2000 Jon Griffiths
   5  * Copyright 2005 Juan Lang
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  20  *
  21  * FIXME: Incomplete support for nested exceptions/try block cleanup.
  22  */
  23
  24 #include "config.h"
  25 #include "wine/port.h"
  26
  27 #include <stdarg.h>
  28
  29 #include "windef.h"
  30 #include "winbase.h"
  31 #include "winternl.h"
  32 #include "wine/exception.h"
  33 #include "msvcrt.h"
  34 #include "excpt.h"
  35 #include "wincon.h"
  36 #include "wine/debug.h"
  37
  38 WINE_DEFAULT_DEBUG_CHANNEL(seh);
  39
  40 /* VC++ extensions to Win32 SEH */
  41 typedef struct _SCOPETABLE
  42 {
  43   int previousTryLevel;
  44   int (*lpfnFilter)(PEXCEPTION_POINTERS);
  45   int (*lpfnHandler)(void);
  46 } SCOPETABLE, *PSCOPETABLE;
  47
  48 typedef struct _MSVCRT_EXCEPTION_FRAME
  49 {
  50   EXCEPTION_REGISTRATION_RECORD *prev;
  51   void (*handler)(PEXCEPTION_RECORD, EXCEPTION_REGISTRATION_RECORD*,
  52                   PCONTEXT, PEXCEPTION_RECORD);
  53   PSCOPETABLE scopetable;
  54   int trylevel;
  55   int _ebp;
  56   PEXCEPTION_POINTERS xpointers;
  57 } MSVCRT_EXCEPTION_FRAME;
  58
  59 #define TRYLEVEL_END (-1) /* End of trylevel list */
  60
  61 #if defined(__GNUC__) && defined(__i386__)
  62 static inline void call_finally_block( void *code_block, void *base_ptr )
  63 {
  64     __asm__ __volatile__ ("movl %1,%%ebp; call *%%eax"
  65                           : : "a" (code_block), "g" (base_ptr));
  66 }
  67
  68 static inline int call_filter( int (*func)(PEXCEPTION_POINTERS), void *arg, void *ebp )
  69 {
  70     int ret;
  71     __asm__ __volatile__ ("pushl %%ebp; pushl %3; movl %2,%%ebp; call *%%eax; popl %%ebp; popl %%ebp"
  72                           : "=a" (ret)
  73                           : "0" (func), "r" (ebp), "r" (arg)
  74                           : "ecx", "edx", "memory" );
  75     return ret;
  76 }
  77
  78 static inline int call_unwind_func( int (*func)(void), void *ebp )
  79 {
  80     int ret;
  81     __asm__ __volatile__ ("pushl %%ebp\n\t"
  82                           "pushl %%ebx\n\t"
  83                           "pushl %%esi\n\t"
  84                           "pushl %%edi\n\t"
  85                           "movl %2,%%ebp\n\t"
  86                           "call *%0\n\t"
  87                           "popl %%edi\n\t"
  88                           "popl %%esi\n\t"
  89                           "popl %%ebx\n\t"
  90                           "popl %%ebp"
  91                           : "=a" (ret)
  92                           : "0" (func), "r" (ebp)
  93                           : "ecx", "edx", "memory" );
  94     return ret;
  95 }
  96
  97 #endif
  98
  99
 100 #ifdef __i386__
 101
 102 static DWORD MSVCRT_nested_handler(PEXCEPTION_RECORD rec,
 103                                    EXCEPTION_REGISTRATION_RECORD* frame,
 104                                    PCONTEXT context,
 105                                    EXCEPTION_REGISTRATION_RECORD** dispatch)
 106 {
 107   if (!(rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)))
 108     return ExceptionContinueSearch;
 109   *dispatch = frame;
 110   return ExceptionCollidedUnwind;
 111 }
 112
 113
 114 /*********************************************************************
 115  *              _EH_prolog (MSVCRT.@)
 116  */
 117
 118 /* Provided for VC++ binary compatibility only */
 119 __ASM_GLOBAL_FUNC(_EH_prolog,
 120                   "pushl $-1\n\t"
 121                   "pushl %eax\n\t"
 122                   "pushl %fs:0\n\t"
 123                   "movl  %esp, %fs:0\n\t"
 124                   "movl  12(%esp), %eax\n\t"
 125                   "movl  %ebp, 12(%esp)\n\t"
 126                   "leal  12(%esp), %ebp\n\t"
 127                   "pushl %eax\n\t"
 128                   "ret")
 129
 130 static void msvcrt_local_unwind2(MSVCRT_EXCEPTION_FRAME* frame, int trylevel, void *ebp)
 131 {
 132   EXCEPTION_REGISTRATION_RECORD reg;
 133
 134   TRACE("(%p,%d,%d)\n",frame, frame->trylevel, trylevel);
 135
 136   /* Register a handler in case of a nested exception */
 137   reg.Handler = MSVCRT_nested_handler;
 138   reg.Prev = NtCurrentTeb()->Tib.ExceptionList;
 139   __wine_push_frame(&reg);
 140
 141   while (frame->trylevel != TRYLEVEL_END && frame->trylevel != trylevel)
 142   {
 143       int level = frame->trylevel;
 144       frame->trylevel = frame->scopetable[level].previousTryLevel;
 145       if (!frame->scopetable[level].lpfnFilter)
 146       {
 147           TRACE( "__try block cleanup level %d handler %p ebp %p\n",
 148                  level, frame->scopetable[level].lpfnHandler, ebp );
 149           call_unwind_func( frame->scopetable[level].lpfnHandler, ebp );
 150       }
 151   }
 152   __wine_pop_frame(&reg);
 153   TRACE("unwound OK\n");
 154 }
 155
 156 /*******************************************************************
 157  *              _local_unwind2 (MSVCRT.@)
 158  */
 159 void CDECL _local_unwind2(MSVCRT_EXCEPTION_FRAME* frame, int trylevel)
 160 {
 161     msvcrt_local_unwind2( frame, trylevel, &frame->_ebp );
 162 }
 163
 164 #endif  /* __i386__ */
 165
 166 /*******************************************************************
 167  *              _global_unwind2 (MSVCRT.@)
 168  */
 169 void CDECL _global_unwind2(EXCEPTION_REGISTRATION_RECORD* frame)
 170 {
 171     TRACE("(%p)\n",frame);
 172     RtlUnwind( frame, 0, 0, 0 );
 173 }
 174
 175 /*********************************************************************
 176  *              _except_handler2 (MSVCRT.@)
 177  */
 178 int CDECL _except_handler2(PEXCEPTION_RECORD rec,
 179                            EXCEPTION_REGISTRATION_RECORD* frame,
 180                            PCONTEXT context,
 181                            EXCEPTION_REGISTRATION_RECORD** dispatcher)
 182 {
 183   FIXME("exception %x flags=%x at %p handler=%p %p %p stub\n",
 184         rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,
 185         frame->Handler, context, dispatcher);
 186   return ExceptionContinueSearch;
 187 }
 188
 189 /*********************************************************************
 190  *              _except_handler3 (MSVCRT.@)
 191  */
 192 int CDECL _except_handler3(PEXCEPTION_RECORD rec,
 193                            MSVCRT_EXCEPTION_FRAME* frame,
 194                            PCONTEXT context, void* dispatcher)
 195 {
 196 #if defined(__GNUC__) && defined(__i386__)
 197   int retval, trylevel;
 198   EXCEPTION_POINTERS exceptPtrs;
 199   PSCOPETABLE pScopeTable;
 200
 201   TRACE("exception %x flags=%x at %p handler=%p %p %p semi-stub\n",
 202         rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,
 203         frame->handler, context, dispatcher);
 204
 205   __asm__ __volatile__ ("cld");
 206
 207   if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
 208   {
 209     /* Unwinding the current frame */
 210     msvcrt_local_unwind2(frame, TRYLEVEL_END, &frame->_ebp);
 211     TRACE("unwound current frame, returning ExceptionContinueSearch\n");
 212     return ExceptionContinueSearch;
 213   }
 214   else
 215   {
 216     /* Hunting for handler */
 217     exceptPtrs.ExceptionRecord = rec;
 218     exceptPtrs.ContextRecord = context;
 219     *((DWORD *)frame-1) = (DWORD)&exceptPtrs;
 220     trylevel = frame->trylevel;
 221     pScopeTable = frame->scopetable;
 222
 223     while (trylevel != TRYLEVEL_END)
 224     {
 225       TRACE( "level %d prev %d filter %p\n", trylevel, pScopeTable[trylevel].previousTryLevel,
 226              pScopeTable[trylevel].lpfnFilter );
 227       if (pScopeTable[trylevel].lpfnFilter)
 228       {
 229         retval = call_filter( pScopeTable[trylevel].lpfnFilter, &exceptPtrs, &frame->_ebp );
 230
 231         TRACE("filter returned %s\n", retval == EXCEPTION_CONTINUE_EXECUTION ?
 232               "CONTINUE_EXECUTION" : retval == EXCEPTION_EXECUTE_HANDLER ?
 233               "EXECUTE_HANDLER" : "CONTINUE_SEARCH");
 234
 235         if (retval == EXCEPTION_CONTINUE_EXECUTION)
 236           return ExceptionContinueExecution;
 237
 238         if (retval == EXCEPTION_EXECUTE_HANDLER)
 239         {
 240           /* Unwind all higher frames, this one will handle the exception */
 241           _global_unwind2((EXCEPTION_REGISTRATION_RECORD*)frame);
 242           msvcrt_local_unwind2(frame, trylevel, &frame->_ebp);
 243
 244           /* Set our trylevel to the enclosing block, and call the __finally
 245            * code, which won't return
 246            */
 247           frame->trylevel = pScopeTable[trylevel].previousTryLevel;
 248           TRACE("__finally block %p\n",pScopeTable[trylevel].lpfnHandler);
 249           call_finally_block(pScopeTable[trylevel].lpfnHandler, &frame->_ebp);
 250           ERR("Returned from __finally block - expect crash!\n");
 251        }
 252       }
 253       trylevel = pScopeTable[trylevel].previousTryLevel;
 254     }
 255   }
 256 #else
 257   FIXME("exception %x flags=%x at %p handler=%p %p %p stub\n",
 258         rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,
 259         frame->handler, context, dispatcher);
 260 #endif
 261   TRACE("reached TRYLEVEL_END, returning ExceptionContinueSearch\n");
 262   return ExceptionContinueSearch;
 263 }
 264
 265 /*********************************************************************
 266  *              _abnormal_termination (MSVCRT.@)
 267  */
 268 int CDECL _abnormal_termination(void)
 269 {
 270   FIXME("(void)stub\n");
 271   return 0;
 272 }
 273
 274 /*
 275  * setjmp/longjmp implementation
 276  */
 277
 278 #ifdef __i386__
 279 #define MSVCRT_JMP_MAGIC 0x56433230 /* ID value for new jump structure */
 280 typedef void (__stdcall *MSVCRT_unwind_function)(const struct MSVCRT___JUMP_BUFFER *);
 281
 282 /* define an entrypoint for setjmp/setjmp3 that stores the registers in the jmp buf */
 283 /* and then jumps to the C backend function */
 284 #define DEFINE_SETJMP_ENTRYPOINT(name) \
 285     __ASM_GLOBAL_FUNC( name, \
 286                        "movl 4(%esp),%ecx\n\t"   /* jmp_buf */      \
 287                        "movl %ebp,0(%ecx)\n\t"   /* jmp_buf.Ebp */  \
 288                        "movl %ebx,4(%ecx)\n\t"   /* jmp_buf.Ebx */  \
 289                        "movl %edi,8(%ecx)\n\t"   /* jmp_buf.Edi */  \
 290                        "movl %esi,12(%ecx)\n\t"  /* jmp_buf.Esi */  \
 291                        "movl %esp,16(%ecx)\n\t"  /* jmp_buf.Esp */  \
 292                        "movl 0(%esp),%eax\n\t"                      \
 293                        "movl %eax,20(%ecx)\n\t"  /* jmp_buf.Eip */  \
 294                        "jmp " __ASM_NAME("__regs_") # name )
 295
 296 /* restore the registers from the jmp buf upon longjmp */
 297 extern void DECLSPEC_NORETURN longjmp_set_regs( struct MSVCRT___JUMP_BUFFER *jmp, int retval );
 298 __ASM_GLOBAL_FUNC( longjmp_set_regs,
 299                    "movl 4(%esp),%ecx\n\t"   /* jmp_buf */
 300                    "movl 8(%esp),%eax\n\t"   /* retval */
 301                    "movl 0(%ecx),%ebp\n\t"   /* jmp_buf.Ebp */
 302                    "movl 4(%ecx),%ebx\n\t"   /* jmp_buf.Ebx */
 303                    "movl 8(%ecx),%edi\n\t"   /* jmp_buf.Edi */
 304                    "movl 12(%ecx),%esi\n\t"  /* jmp_buf.Esi */
 305                    "movl 16(%ecx),%esp\n\t"  /* jmp_buf.Esp */
 306                    "addl $4,%esp\n\t"        /* get rid of return address */
 307                    "jmp *20(%ecx)\n\t"       /* jmp_buf.Eip */ )
 308
 309 /*
 310  * The signatures of the setjmp/longjmp functions do not match that
 311  * declared in the setjmp header so they don't follow the regular naming
 312  * convention to avoid conflicts.
 313  */
 314
 315 /*******************************************************************
 316  *              _setjmp (MSVCRT.@)
 317  */
 318 DEFINE_SETJMP_ENTRYPOINT(MSVCRT__setjmp)
 319 int CDECL __regs_MSVCRT__setjmp(struct MSVCRT___JUMP_BUFFER *jmp)
 320 {
 321     jmp->Registration = (unsigned long)NtCurrentTeb()->Tib.ExceptionList;
 322     if (jmp->Registration == ~0UL)
 323         jmp->TryLevel = TRYLEVEL_END;
 324     else
 325         jmp->TryLevel = ((MSVCRT_EXCEPTION_FRAME*)jmp->Registration)->trylevel;
 326
 327     TRACE("buf=%p ebx=%08lx esi=%08lx edi=%08lx ebp=%08lx esp=%08lx eip=%08lx frame=%08lx\n",
 328           jmp, jmp->Ebx, jmp->Esi, jmp->Edi, jmp->Ebp, jmp->Esp, jmp->Eip, jmp->Registration );
 329     return 0;
 330 }
 331
 332 /*******************************************************************
 333  *              _setjmp3 (MSVCRT.@)
 334  */
 335 DEFINE_SETJMP_ENTRYPOINT( MSVCRT__setjmp3 )
 336 int CDECL __regs_MSVCRT__setjmp3(struct MSVCRT___JUMP_BUFFER *jmp, int nb_args, ...)
 337 {
 338     jmp->Cookie = MSVCRT_JMP_MAGIC;
 339     jmp->UnwindFunc = 0;
 340     jmp->Registration = (unsigned long)NtCurrentTeb()->Tib.ExceptionList;
 341     if (jmp->Registration == ~0UL)
 342     {
 343         jmp->TryLevel = TRYLEVEL_END;
 344     }
 345     else
 346     {
 347         int i;
 348         va_list args;
 349
 350         va_start( args, nb_args );
 351         if (nb_args > 0) jmp->UnwindFunc = va_arg( args, unsigned long );
 352         if (nb_args > 1) jmp->TryLevel = va_arg( args, unsigned long );
 353         else jmp->TryLevel = ((MSVCRT_EXCEPTION_FRAME*)jmp->Registration)->trylevel;
 354         for (i = 0; i < 6 && i < nb_args - 2; i++)
 355             jmp->UnwindData[i] = va_arg( args, unsigned long );
 356         va_end( args );
 357     }
 358
 359     TRACE("buf=%p ebx=%08lx esi=%08lx edi=%08lx ebp=%08lx esp=%08lx eip=%08lx frame=%08lx\n",
 360           jmp, jmp->Ebx, jmp->Esi, jmp->Edi, jmp->Ebp, jmp->Esp, jmp->Eip, jmp->Registration );
 361     return 0;
 362 }
 363
 364 /*********************************************************************
 365  *              longjmp (MSVCRT.@)
 366  */
 367 int CDECL MSVCRT_longjmp(struct MSVCRT___JUMP_BUFFER *jmp, int retval)
 368 {
 369     unsigned long cur_frame = 0;
 370
 371     TRACE("buf=%p ebx=%08lx esi=%08lx edi=%08lx ebp=%08lx esp=%08lx eip=%08lx frame=%08lx retval=%08x\n",
 372           jmp, jmp->Ebx, jmp->Esi, jmp->Edi, jmp->Ebp, jmp->Esp, jmp->Eip, jmp->Registration, retval );
 373
 374     cur_frame=(unsigned long)NtCurrentTeb()->Tib.ExceptionList;
 375     TRACE("cur_frame=%lx\n",cur_frame);
 376
 377     if (cur_frame != jmp->Registration)
 378         _global_unwind2((EXCEPTION_REGISTRATION_RECORD*)jmp->Registration);
 379
 380     if (jmp->Registration)
 381     {
 382         if (!IsBadReadPtr(&jmp->Cookie, sizeof(long)) &&
 383             jmp->Cookie == MSVCRT_JMP_MAGIC && jmp->UnwindFunc)
 384         {
 385             MSVCRT_unwind_function unwind_func;
 386
 387             unwind_func=(MSVCRT_unwind_function)jmp->UnwindFunc;
 388             unwind_func(jmp);
 389         }
 390         else
 391             msvcrt_local_unwind2((MSVCRT_EXCEPTION_FRAME*)jmp->Registration,
 392                                  jmp->TryLevel, (void *)jmp->Ebp);
 393     }
 394
 395     if (!retval)
 396         retval = 1;
 397
 398     longjmp_set_regs( jmp, retval );
 399 }
 400
 401 /*********************************************************************
 402  *              _seh_longjmp_unwind (MSVCRT.@)
 403  */
 404 void __stdcall _seh_longjmp_unwind(struct MSVCRT___JUMP_BUFFER *jmp)
 405 {
 406     msvcrt_local_unwind2( (MSVCRT_EXCEPTION_FRAME *)jmp->Registration, jmp->TryLevel, (void *)jmp->Ebp );
 407 }
 408 #endif /* i386 */
 409
 410 static MSVCRT___sighandler_t sighandlers[MSVCRT_NSIG] = { MSVCRT_SIG_DFL };
 411
 412 static BOOL WINAPI msvcrt_console_handler(DWORD ctrlType)
 413 {
 414     BOOL ret = FALSE;
 415
 416     switch (ctrlType)
 417     {
 418     case CTRL_C_EVENT:
 419         if (sighandlers[MSVCRT_SIGINT])
 420         {
 421             if (sighandlers[MSVCRT_SIGINT] != MSVCRT_SIG_IGN)
 422                 sighandlers[MSVCRT_SIGINT](MSVCRT_SIGINT);
 423             ret = TRUE;
 424         }
 425         break;
 426     }
 427     return ret;
 428 }
 429
 430 typedef void (*float_handler)(int, int);
 431
 432 /* The exception codes are actually NTSTATUS values */
 433 static const struct
 434 {
 435     NTSTATUS status;
 436     int signal;
 437 } float_exception_map[] = {
 438  { EXCEPTION_FLT_DENORMAL_OPERAND, MSVCRT__FPE_DENORMAL },
 439  { EXCEPTION_FLT_DIVIDE_BY_ZERO, MSVCRT__FPE_ZERODIVIDE },
 440  { EXCEPTION_FLT_INEXACT_RESULT, MSVCRT__FPE_INEXACT },
 441  { EXCEPTION_FLT_INVALID_OPERATION, MSVCRT__FPE_INVALID },
 442  { EXCEPTION_FLT_OVERFLOW, MSVCRT__FPE_OVERFLOW },
 443  { EXCEPTION_FLT_STACK_CHECK, MSVCRT__FPE_STACKOVERFLOW },
 444  { EXCEPTION_FLT_UNDERFLOW, MSVCRT__FPE_UNDERFLOW },
 445 };
 446
 447 static LONG WINAPI msvcrt_exception_filter(struct _EXCEPTION_POINTERS *except)
 448 {
 449     LONG ret = EXCEPTION_CONTINUE_SEARCH;
 450     MSVCRT___sighandler_t handler;
 451
 452     if (!except || !except->ExceptionRecord)
 453         return EXCEPTION_CONTINUE_SEARCH;
 454
 455     switch (except->ExceptionRecord->ExceptionCode)
 456     {
 457     case EXCEPTION_ACCESS_VIOLATION:
 458         if ((handler = sighandlers[MSVCRT_SIGSEGV]) != MSVCRT_SIG_DFL)
 459         {
 460             if (handler != MSVCRT_SIG_IGN)
 461             {
 462                 sighandlers[MSVCRT_SIGSEGV] = MSVCRT_SIG_DFL;
 463                 handler(MSVCRT_SIGSEGV);
 464             }
 465             ret = EXCEPTION_CONTINUE_EXECUTION;
 466         }
 467         break;
 468     /* According to msdn,
 469      * the FPE signal handler takes as a second argument the type of
 470      * floating point exception.
 471      */
 472     case EXCEPTION_FLT_DENORMAL_OPERAND:
 473     case EXCEPTION_FLT_DIVIDE_BY_ZERO:
 474     case EXCEPTION_FLT_INEXACT_RESULT:
 475     case EXCEPTION_FLT_INVALID_OPERATION:
 476     case EXCEPTION_FLT_OVERFLOW:
 477     case EXCEPTION_FLT_STACK_CHECK:
 478     case EXCEPTION_FLT_UNDERFLOW:
 479         if ((handler = sighandlers[MSVCRT_SIGFPE]) != MSVCRT_SIG_DFL)
 480         {
 481             if (handler != MSVCRT_SIG_IGN)
 482             {
 483                 unsigned int i;
 484                 int float_signal = MSVCRT__FPE_INVALID;
 485
 486                 sighandlers[MSVCRT_SIGFPE] = MSVCRT_SIG_DFL;
 487                 for (i = 0; i < sizeof(float_exception_map) /
 488                          sizeof(float_exception_map[0]); i++)
 489                 {
 490                     if (float_exception_map[i].status ==
 491                         except->ExceptionRecord->ExceptionCode)
 492                     {
 493                         float_signal = float_exception_map[i].signal;
 494                         break;
 495                     }
 496                 }
 497                 ((float_handler)handler)(MSVCRT_SIGFPE, float_signal);
 498             }
 499             ret = EXCEPTION_CONTINUE_EXECUTION;
 500         }
 501         break;
 502     case EXCEPTION_ILLEGAL_INSTRUCTION:
 503     case EXCEPTION_PRIV_INSTRUCTION:
 504         if ((handler = sighandlers[MSVCRT_SIGILL]) != MSVCRT_SIG_DFL)
 505         {
 506             if (handler != MSVCRT_SIG_IGN)
 507             {
 508                 sighandlers[MSVCRT_SIGILL] = MSVCRT_SIG_DFL;
 509                 handler(MSVCRT_SIGILL);
 510             }
 511             ret = EXCEPTION_CONTINUE_EXECUTION;
 512         }
 513         break;
 514     }
 515     return ret;
 516 }
 517
 518 void msvcrt_init_signals(void)
 519 {
 520     SetConsoleCtrlHandler(msvcrt_console_handler, TRUE);
 521     SetUnhandledExceptionFilter(msvcrt_exception_filter);
 522 }
 523
 524 void msvcrt_free_signals(void)
 525 {
 526     SetConsoleCtrlHandler(msvcrt_console_handler, FALSE);
 527     SetUnhandledExceptionFilter(NULL);
 528 }
 529
 530 /*********************************************************************
 531  *              signal (MSVCRT.@)
 532  * Some signals may never be generated except through an explicit call to
 533  * raise.
 534  */
 535 MSVCRT___sighandler_t CDECL MSVCRT_signal(int sig, MSVCRT___sighandler_t func)
 536 {
 537     MSVCRT___sighandler_t ret = MSVCRT_SIG_ERR;
 538
 539     TRACE("(%d, %p)\n", sig, func);
 540
 541     if (func == MSVCRT_SIG_ERR) return MSVCRT_SIG_ERR;
 542
 543     switch (sig)
 544     {
 545     /* Cases handled internally.  Note SIGTERM is never generated by Windows,
 546      * so we effectively mask it.
 547      */
 548     case MSVCRT_SIGABRT:
 549     case MSVCRT_SIGFPE:
 550     case MSVCRT_SIGILL:
 551     case MSVCRT_SIGSEGV:
 552     case MSVCRT_SIGINT:
 553     case MSVCRT_SIGTERM:
 554         ret = sighandlers[sig];
 555         sighandlers[sig] = func;
 556         break;
 557     default:
 558         ret = MSVCRT_SIG_ERR;
 559     }
 560     return ret;
 561 }
 562
 563 /*********************************************************************
 564  *              raise (MSVCRT.@)
 565  */
 566 int CDECL MSVCRT_raise(int sig)
 567 {
 568     MSVCRT___sighandler_t handler;
 569
 570     TRACE("(%d)\n", sig);
 571
 572     switch (sig)
 573     {
 574     case MSVCRT_SIGABRT:
 575     case MSVCRT_SIGFPE:
 576     case MSVCRT_SIGILL:
 577     case MSVCRT_SIGSEGV:
 578     case MSVCRT_SIGINT:
 579     case MSVCRT_SIGTERM:
 580         handler = sighandlers[sig];
 581         if (handler == MSVCRT_SIG_DFL) MSVCRT__exit(3);
 582         if (handler != MSVCRT_SIG_IGN)
 583         {
 584             sighandlers[sig] = MSVCRT_SIG_DFL;
 585             if (sig == MSVCRT_SIGFPE)
 586                 ((float_handler)handler)(sig, MSVCRT__FPE_EXPLICITGEN);
 587             else
 588                 handler(sig);
 589         }
 590         break;
 591     default:
 592         return -1;
 593     }
 594     return 0;
 595 }
 596
 597 /*********************************************************************
 598  *              _XcptFilter (MSVCRT.@)
 599  */
 600 int CDECL _XcptFilter(NTSTATUS ex, PEXCEPTION_POINTERS ptr)
 601 {
 602     TRACE("(%08x,%p)\n", ex, ptr);
 603     /* I assume ptr->ExceptionRecord->ExceptionCode is the same as ex */
 604     return msvcrt_exception_filter(ptr);
 605 }