win32/except.c

   1 /*
   2  * Win32 exception functions
   3  *
   4  * Copyright (c) 1996 Onno Hovers, (onno@stack.urc.tue.nl)
   5  * Copyright (c) 1999 Alexandre Julliard
   6  *
   7  * Notes:
   8  *  What really happens behind the scenes of those new
   9  *  __try{...}__except(..){....}  and
  10  *  __try{...}__finally{...}
  11  *  statements is simply not documented by Microsoft. There could be different
  12  *  reasons for this:
  13  *  One reason could be that they try to hide the fact that exception
  14  *  handling in Win32 looks almost the same as in OS/2 2.x.
  15  *  Another reason could be that Microsoft does not want others to write
  16  *  binary compatible implementations of the Win32 API (like us).
  17  *
  18  *  Whatever the reason, THIS SUCKS!! Ensuring portability or future
  19  *  compatibility may be valid reasons to keep some things undocumented.
  20  *  But exception handling is so basic to Win32 that it should be
  21  *  documented!
  22  *
  23  */
  24
  25 #include <stdio.h>
  26 #include "windef.h"
  27 #include "winerror.h"
  28 #include "ntddk.h"
  29 #include "wingdi.h"
  30 #include "winuser.h"
  31 #include "wine/exception.h"
  32 #include "thread.h"
  33 #include "stackframe.h"
  34 #include "wine/server.h"
  35 #include "debugtools.h"
  36
  37 DEFAULT_DEBUG_CHANNEL(seh);
  38
  39 static PTOP_LEVEL_EXCEPTION_FILTER top_filter;
  40
  41 typedef INT (WINAPI *MessageBoxA_funcptr)(HWND,LPCSTR,LPCSTR,UINT);
  42 typedef INT (WINAPI *MessageBoxW_funcptr)(HWND,LPCWSTR,LPCWSTR,UINT);
  43
  44 /*******************************************************************
  45  *         RaiseException  (KERNEL32.@)
  46  */
  47 void WINAPI RaiseException( DWORD code, DWORD flags, DWORD nbargs, const LPDWORD args )
  48 {
  49     EXCEPTION_RECORD record;
  50
  51     /* Compose an exception record */
  52
  53     record.ExceptionCode    = code;
  54     record.ExceptionFlags   = flags & EH_NONCONTINUABLE;
  55     record.ExceptionRecord  = NULL;
  56     record.ExceptionAddress = RaiseException;
  57     if (nbargs && args)
  58     {
  59         if (nbargs > EXCEPTION_MAXIMUM_PARAMETERS) nbargs = EXCEPTION_MAXIMUM_PARAMETERS;
  60         record.NumberParameters = nbargs;
  61         memcpy( record.ExceptionInformation, args, nbargs * sizeof(*args) );
  62     }
  63     else record.NumberParameters = 0;
  64
  65     RtlRaiseException( &record );
  66 }
  67
  68
  69 /*******************************************************************
  70  *         format_exception_msg
  71  */
  72 static int format_exception_msg( const EXCEPTION_POINTERS *ptr, char *buffer, int size )
  73 {
  74     const EXCEPTION_RECORD *rec = ptr->ExceptionRecord;
  75     int len,len2;
  76
  77     switch(rec->ExceptionCode)
  78     {
  79     case EXCEPTION_INT_DIVIDE_BY_ZERO:
  80         len = snprintf( buffer, size, "Unhandled division by zero" );
  81         break;
  82     case EXCEPTION_INT_OVERFLOW:
  83         len = snprintf( buffer, size, "Unhandled overflow" );
  84         break;
  85     case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
  86         len = snprintf( buffer, size, "Unhandled array bounds" );
  87         break;
  88     case EXCEPTION_ILLEGAL_INSTRUCTION:
  89         len = snprintf( buffer, size, "Unhandled illegal instruction" );
  90         break;
  91     case EXCEPTION_STACK_OVERFLOW:
  92         len = snprintf( buffer, size, "Unhandled stack overflow" );
  93         break;
  94     case EXCEPTION_PRIV_INSTRUCTION:
  95         len = snprintf( buffer, size, "Unhandled priviledged instruction" );
  96         break;
  97     case EXCEPTION_ACCESS_VIOLATION:
  98         if (rec->NumberParameters == 2)
  99             len = snprintf( buffer, size, "Unhandled page fault on %s access to 0x%08lx",
 100                      rec->ExceptionInformation[0] ? "write" : "read",
 101                      rec->ExceptionInformation[1]);
 102         else
 103             len = snprintf( buffer, size, "Unhandled page fault");
 104         break;
 105     case EXCEPTION_DATATYPE_MISALIGNMENT:
 106         len = snprintf( buffer, size, "Unhandled alignment" );
 107         break;
 108     case CONTROL_C_EXIT:
 109         len = snprintf( buffer, size, "Unhandled ^C");
 110         break;
 111     case EXCEPTION_CRITICAL_SECTION_WAIT:
 112         len = snprintf( buffer, size, "Critical section %08lx wait failed",
 113                  rec->ExceptionInformation[0]);
 114         break;
 115     case EXCEPTION_WINE_STUB:
 116         len = snprintf( buffer, size, "Unimplemented function %s.%s called",
 117                  (char *)rec->ExceptionInformation[0], (char *)rec->ExceptionInformation[1] );
 118         break;
 119     case EXCEPTION_VM86_INTx:
 120         len = snprintf( buffer, size, "Unhandled interrupt %02lx in vm86 mode",
 121                  rec->ExceptionInformation[0]);
 122         break;
 123     case EXCEPTION_VM86_STI:
 124         len = snprintf( buffer, size, "Unhandled sti in vm86 mode");
 125         break;
 126     case EXCEPTION_VM86_PICRETURN:
 127         len = snprintf( buffer, size, "Unhandled PIC return in vm86 mode");
 128         break;
 129     default:
 130         len = snprintf( buffer, size, "Unhandled exception 0x%08lx", rec->ExceptionCode);
 131         break;
 132     }
 133     if ((len<0) || (len>=size))
 134         return -1;
 135 #ifdef __i386__
 136     if (ptr->ContextRecord->SegCs != __get_cs())
 137         len2 = snprintf(buffer+len, size-len,
 138                         " at address 0x%04lx:0x%08lx.\nDo you wish to debug it ?",
 139                         ptr->ContextRecord->SegCs,
 140                         (DWORD)ptr->ExceptionRecord->ExceptionAddress);
 141     else
 142 #endif
 143         len2 = snprintf(buffer+len, size-len,
 144                         " at address 0x%08lx.\nDo you wish to debug it ?",
 145                         (DWORD)ptr->ExceptionRecord->ExceptionAddress);
 146     if ((len2<0) || (len>=size-len))
 147         return -1;
 148     return len+len2;
 149 }
 150
 151
 152 /**********************************************************************
 153  *           send_debug_event
 154  *
 155  * Send an EXCEPTION_DEBUG_EVENT event to the debugger.
 156  */
 157 static int send_debug_event( EXCEPTION_RECORD *rec, int first_chance, CONTEXT *context )
 158 {
 159     int ret;
 160     HANDLE handle = 0;
 161
 162     SERVER_START_VAR_REQ( queue_exception_event, sizeof(*rec) + sizeof(*context) )
 163     {
 164         CONTEXT *context_ptr = server_data_ptr(req);
 165         EXCEPTION_RECORD *rec_ptr = (EXCEPTION_RECORD *)(context_ptr + 1);
 166         req->first   = first_chance;
 167         *rec_ptr     = *rec;
 168         *context_ptr = *context;
 169         if (!SERVER_CALL()) handle = req->handle;
 170     }
 171     SERVER_END_VAR_REQ;
 172     if (!handle) return 0;  /* no debugger present or other error */
 173
 174     /* No need to wait on the handle since the process gets suspended
 175      * once the event is passed to the debugger, so when we get back
 176      * here the event has been continued already.
 177      */
 178     SERVER_START_VAR_REQ( get_exception_status, sizeof(*context) )
 179     {
 180         req->handle = handle;
 181         if (!SERVER_CALL()) *context = *(CONTEXT *)server_data_ptr(req);
 182         ret = req->status;
 183     }
 184     SERVER_END_VAR_REQ;
 185     NtClose( handle );
 186     return ret;
 187 }
 188
 189 /******************************************************************
 190  *              start_debugger
 191  *
 192  * Does the effective debugger startup according to 'format'
 193  */
 194 static BOOL     start_debugger(PEXCEPTION_POINTERS epointers, HANDLE hEvent)
 195 {
 196     HKEY                hDbgConf;
 197     DWORD               bAuto = FALSE;
 198     PROCESS_INFORMATION info;
 199     STARTUPINFOA        startup;
 200     char                buffer[256];
 201     char                format[256];
 202
 203     if (!RegOpenKeyA(HKEY_LOCAL_MACHINE,
 204                      "Software\\Microsoft\\Windows NT\\CurrentVersion\\AeDebug", &hDbgConf)) {
 205        DWORD    type;
 206        DWORD    count;
 207
 208        count = sizeof(format);
 209        if (RegQueryValueExA(hDbgConf, "Debugger", 0, &type, format, &count))
 210           format[0] = 0;
 211
 212        count = sizeof(bAuto);
 213        if (RegQueryValueExA(hDbgConf, "Auto", 0, &type, (char*)&bAuto, &count))
 214           bAuto = TRUE;
 215        else if (type == REG_SZ)
 216        {
 217            char autostr[10];
 218            count = sizeof(autostr);
 219            if (!RegQueryValueExA(hDbgConf, "Auto", 0, &type, autostr, &count))
 220                bAuto = atoi(autostr);
 221        }
 222        RegCloseKey(hDbgConf);
 223     } else {
 224         /* try a default setup... */
 225         strcpy( format, "debugger/winedbg %ld %ld" );
 226     }
 227
 228     if (!bAuto)
 229     {
 230         HMODULE                 mod = GetModuleHandleA( "user32.dll" );
 231         MessageBoxA_funcptr     pMessageBoxA = NULL;
 232
 233         if (mod) pMessageBoxA = (MessageBoxA_funcptr)GetProcAddress( mod, "MessageBoxA" );
 234         if (pMessageBoxA)
 235         {
 236             format_exception_msg( epointers, buffer, sizeof(buffer) );
 237             if (pMessageBoxA( 0, buffer, "Exception raised", MB_YESNO | MB_ICONHAND ) == IDNO)
 238             {
 239                 TRACE("Killing process\n");
 240                 return FALSE;
 241             }
 242         }
 243     }
 244
 245     TRACE("Starting debugger (fmt=%s)\n", format);
 246     sprintf(buffer, format, GetCurrentProcessId(), hEvent);
 247     memset(&startup, 0, sizeof(startup));
 248     startup.cb = sizeof(startup);
 249     startup.dwFlags = STARTF_USESHOWWINDOW;
 250     startup.wShowWindow = SW_SHOWNORMAL;
 251     if (CreateProcessA(NULL, buffer, NULL, NULL, TRUE, 0, NULL, NULL, &startup, &info)) {
 252         /* wait for debugger to come up... */
 253         WaitForSingleObject(hEvent, INFINITE);
 254         return TRUE;
 255     }
 256     ERR("Couldn't start debugger (%s) (%ld)\n"
 257         "Read the Wine Developers Guide on how to set up winedbg or another debugger\n",
 258         buffer, GetLastError());
 259     return FALSE;
 260 }
 261
 262 /******************************************************************
 263  *              start_debugger_atomic
 264  *
 265  * starts the debugger is an atomic way:
 266  *      - either the debugger is not started and it is started
 267  *      - either the debugger has already been started by an other thread
 268  *      - either the debugger couldn't be started
 269  *
 270  * returns TRUE for the two first condition, FALSE for the last
 271  */
 272 static  int     start_debugger_atomic(PEXCEPTION_POINTERS epointers)
 273 {
 274     static HANDLE       hRunOnce /* = 0 */;
 275
 276     if (hRunOnce == 0)
 277     {
 278         OBJECT_ATTRIBUTES       attr;
 279         HANDLE                  hEvent;
 280
 281         attr.Length                   = sizeof(attr);
 282         attr.RootDirectory            = 0;
 283         attr.Attributes               = OBJ_INHERIT;
 284         attr.ObjectName               = NULL;
 285         attr.SecurityDescriptor       = NULL;
 286         attr.SecurityQualityOfService = NULL;
 287
 288         /* ask for manual reset, so that once the debugger is started, every thread will be
 289          * know it
 290          */
 291         NtCreateEvent( &hEvent, EVENT_ALL_ACCESS, &attr, TRUE, FALSE );
 292         if (InterlockedCompareExchange( (LPLONG)&hRunOnce, hEvent, 0 ) == 0)
 293         {
 294             /* ok, our event has been set... we're the winning thread */
 295             BOOL        ret = start_debugger( epointers, hRunOnce );
 296             DWORD       tmp;
 297
 298             if (!ret)
 299             {
 300                 /* so that the other threads won't be stuck */
 301                 NtSetEvent( hRunOnce, &tmp );
 302             }
 303             return ret;
 304         }
 305
 306         /* someone beat us here... */
 307         CloseHandle( hEvent );
 308     }
 309
 310     /* and wait for the winner to have actually created the debugger */
 311     WaitForSingleObject( hRunOnce, INFINITE );
 312     /* in fact, here, we only know that someone has tried to start the debugger, we'll know
 313      * by reposting the exception if it has actually attached to the current process
 314      */
 315     return TRUE;
 316 }
 317
 318
 319 /*******************************************************************
 320  *         UnhandledExceptionFilter   (KERNEL32.@)
 321  */
 322 DWORD WINAPI UnhandledExceptionFilter(PEXCEPTION_POINTERS epointers)
 323 {
 324     int                 status;
 325     int                 loop = 0;
 326
 327     for (loop = 0; loop <= 1; loop++)
 328     {
 329         /* send a last chance event to the debugger */
 330         status = send_debug_event( epointers->ExceptionRecord, FALSE, epointers->ContextRecord );
 331         switch (status)
 332         {
 333         case DBG_CONTINUE:
 334             return EXCEPTION_CONTINUE_EXECUTION;
 335         case DBG_EXCEPTION_NOT_HANDLED:
 336             TerminateProcess( GetCurrentProcess(), epointers->ExceptionRecord->ExceptionCode );
 337             break; /* not reached */
 338         case 0: /* no debugger is present */
 339             if (epointers->ExceptionRecord->ExceptionCode == CONTROL_C_EXIT)
 340             {
 341                 /* do not launch the debugger on ^C, simply terminate the process */
 342                 TerminateProcess( GetCurrentProcess(), 1 );
 343             }
 344             /* second try, the debugger isn't present... */
 345             if (loop == 1) return EXCEPTION_EXECUTE_HANDLER;
 346             break;
 347         default:
 348             FIXME("Unsupported yet debug continue value %d (please report)\n", status);
 349             return EXCEPTION_EXECUTE_HANDLER;
 350         }
 351
 352         /* should only be there when loop == 0 */
 353
 354         if (top_filter)
 355         {
 356             DWORD ret = top_filter( epointers );
 357             if (ret != EXCEPTION_CONTINUE_SEARCH) return ret;
 358         }
 359
 360         /* FIXME: Should check the current error mode */
 361
 362         if (!start_debugger_atomic( epointers ))
 363             return EXCEPTION_EXECUTE_HANDLER;
 364         /* now that we should have a debugger attached, try to resend event */
 365     }
 366
 367     return EXCEPTION_EXECUTE_HANDLER;
 368 }
 369
 370
 371 /***********************************************************************
 372  *            SetUnhandledExceptionFilter   (KERNEL32.@)
 373  */
 374 LPTOP_LEVEL_EXCEPTION_FILTER WINAPI SetUnhandledExceptionFilter(
 375                                           LPTOP_LEVEL_EXCEPTION_FILTER filter )
 376 {
 377     LPTOP_LEVEL_EXCEPTION_FILTER old = top_filter;
 378     top_filter = filter;
 379     return old;
 380 }
 381
 382
 383 /**************************************************************************
 384  *           FatalAppExitA   (KERNEL32.@)
 385  */
 386 void WINAPI FatalAppExitA( UINT action, LPCSTR str )
 387 {
 388     HMODULE mod = GetModuleHandleA( "user32.dll" );
 389     MessageBoxA_funcptr pMessageBoxA = NULL;
 390
 391     WARN("AppExit\n");
 392
 393     if (mod) pMessageBoxA = (MessageBoxA_funcptr)GetProcAddress( mod, "MessageBoxA" );
 394     if (pMessageBoxA) pMessageBoxA( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 395     else ERR( "%s\n", debugstr_a(str) );
 396     ExitProcess(0);
 397 }
 398
 399
 400 /**************************************************************************
 401  *           FatalAppExitW   (KERNEL32.@)
 402  */
 403 void WINAPI FatalAppExitW( UINT action, LPCWSTR str )
 404 {
 405     HMODULE mod = GetModuleHandleA( "user32.dll" );
 406     MessageBoxW_funcptr pMessageBoxW = NULL;
 407
 408     WARN("AppExit\n");
 409
 410     if (mod) pMessageBoxW = (MessageBoxW_funcptr)GetProcAddress( mod, "MessageBoxW" );
 411     if (pMessageBoxW) pMessageBoxW( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 412     else ERR( "%s\n", debugstr_w(str) );
 413     ExitProcess(0);
 414 }