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 portabilty or future
  19  *  compatability 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 <assert.h>
  26 #include <stdio.h>
  27 #include "windef.h"
  28 #include "wingdi.h"
  29 #include "winuser.h"
  30 #include "winerror.h"
  31 #include "ntddk.h"
  32 #include "wine/exception.h"
  33 #include "ldt.h"
  34 #include "callback.h"
  35 #include "process.h"
  36 #include "thread.h"
  37 #include "stackframe.h"
  38 #include "server.h"
  39 #include "debugtools.h"
  40
  41 DEFAULT_DEBUG_CHANNEL(seh);
  42
  43
  44 /*******************************************************************
  45  *         RaiseException  (KERNEL32.418)
  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  *         UnhandledExceptionFilter   (KERNEL32.537)
  71  */
  72 DWORD WINAPI UnhandledExceptionFilter(PEXCEPTION_POINTERS epointers)
  73 {
  74     struct exception_event_request *req = get_req_buffer();
  75     PDB*                pdb = PROCESS_Current();
  76     char                format[256];
  77     char                buffer[256];
  78     HKEY                hDbgConf;
  79     DWORD               bAuto = FALSE;
  80     DWORD               ret = EXCEPTION_EXECUTE_HANDLER;
  81
  82     /* send a last chance event to the debugger */
  83     req->record  = *epointers->ExceptionRecord;
  84     req->first   = 0;
  85     req->context = *epointers->ContextRecord;
  86     if (!server_call_noerr( REQ_EXCEPTION_EVENT )) *epointers->ContextRecord = req->context;
  87     switch (req->status)
  88     {
  89     case DBG_CONTINUE:
  90        return EXCEPTION_CONTINUE_EXECUTION;
  91     case DBG_EXCEPTION_NOT_HANDLED:
  92        TerminateProcess( GetCurrentProcess(), epointers->ExceptionRecord->ExceptionCode );
  93        break; /* not reached */
  94     case 0: /* no debugger is present */
  95        break;
  96     default:
  97        FIXME("Unsupported yet debug continue value %d (please report)\n", req->status);
  98     }
  99
 100     if (pdb->top_filter)
 101     {
 102         DWORD ret = pdb->top_filter( epointers );
 103         if (ret != EXCEPTION_CONTINUE_SEARCH) return ret;
 104     }
 105
 106     /* FIXME: Should check the current error mode */
 107
 108     if (!RegOpenKeyA(HKEY_LOCAL_MACHINE,
 109                      "Software\\Microsoft\\Windows NT\\CurrentVersion\\AeDebug",
 110                      &hDbgConf)) {
 111        DWORD    type;
 112        DWORD    count;
 113
 114        count = sizeof(format);
 115        if (RegQueryValueExA(hDbgConf, "Debugger", 0, &type, format, &count))
 116           format[0] = 0;
 117
 118        count = sizeof(bAuto);
 119        if (RegQueryValueExA(hDbgConf, "Auto", 0, &type, (char*)&bAuto, &count))
 120           bAuto = FALSE;
 121
 122        RegCloseKey(hDbgConf);
 123     } else {
 124        /* format[0] = 0; */
 125        strcpy(format, "debugger/winedbg %ld %ld");
 126     }
 127
 128     if (!bAuto && Callout.MessageBoxA) {
 129        sprintf( buffer, "Unhandled exception 0x%08lx at address 0x%08lx.\n"
 130                         "Do you wish to debug it ?",
 131                 epointers->ExceptionRecord->ExceptionCode,
 132                 (DWORD)epointers->ExceptionRecord->ExceptionAddress );
 133        if (Callout.MessageBoxA( 0, buffer, "Error", MB_YESNO | MB_ICONHAND ) == IDNO) {
 134           TRACE("Killing process\n");
 135           return EXCEPTION_EXECUTE_HANDLER;
 136        }
 137     }
 138
 139     if (format[0]) {
 140        HANDLE                   hEvent;
 141        PROCESS_INFORMATION      info;
 142        STARTUPINFOA             startup;
 143
 144        TRACE("Starting debugger (fmt=%s)\n", format);
 145        hEvent = ConvertToGlobalHandle(CreateEventA(NULL, FALSE, FALSE, NULL));
 146        sprintf(buffer, format, GetCurrentProcessId(), hEvent);
 147        memset(&startup, 0, sizeof(startup));
 148        startup.cb = sizeof(startup);
 149        startup.dwFlags = STARTF_USESHOWWINDOW;
 150        startup.wShowWindow = SW_SHOWNORMAL;
 151        if (CreateProcessA(NULL, buffer, NULL, NULL,
 152                           TRUE, 0, NULL, NULL, &startup, &info)) {
 153           WaitForSingleObject(hEvent, INFINITE);
 154           ret = EXCEPTION_CONTINUE_SEARCH;
 155        } else {
 156           ERR("Couldn't start debugger (%s) (%ld)\n", buffer, GetLastError());
 157        }
 158        CloseHandle(hEvent);
 159     } else {
 160        ERR("No standard debugger defined in the registry => no debugging session\n");
 161     }
 162
 163     return ret;
 164 }
 165
 166
 167 /***********************************************************************
 168  *            SetUnhandledExceptionFilter   (KERNEL32.516)
 169  */
 170 LPTOP_LEVEL_EXCEPTION_FILTER WINAPI SetUnhandledExceptionFilter(
 171                                           LPTOP_LEVEL_EXCEPTION_FILTER filter )
 172 {
 173     PDB *pdb = PROCESS_Current();
 174     LPTOP_LEVEL_EXCEPTION_FILTER old = pdb->top_filter;
 175     pdb->top_filter = filter;
 176     return old;
 177 }
 178
 179
 180 /**************************************************************************
 181  *           FatalAppExit16   (KERNEL.137)
 182  */
 183 void WINAPI FatalAppExit16( UINT16 action, LPCSTR str )
 184 {
 185     WARN("AppExit\n");
 186     FatalAppExitA( action, str );
 187 }
 188
 189
 190 /**************************************************************************
 191  *           FatalAppExitA   (KERNEL32.108)
 192  */
 193 void WINAPI FatalAppExitA( UINT action, LPCSTR str )
 194 {
 195     WARN("AppExit\n");
 196     Callout.MessageBoxA( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 197     ExitProcess(0);
 198 }
 199
 200
 201 /**************************************************************************
 202  *           FatalAppExitW   (KERNEL32.109)
 203  */
 204 void WINAPI FatalAppExitW( UINT action, LPCWSTR str )
 205 {
 206     WARN("AppExit\n");
 207     Callout.MessageBoxW( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 208     ExitProcess(0);
 209 }
 210
 211
 212 /*************************************************************
 213  *            WINE_exception_handler
 214  *
 215  * Exception handler for exception blocks declared in Wine code.
 216  */
 217 DWORD WINE_exception_handler( EXCEPTION_RECORD *record, EXCEPTION_FRAME *frame,
 218                               CONTEXT *context, LPVOID pdispatcher )
 219 {
 220     __WINE_FRAME *wine_frame = (__WINE_FRAME *)frame;
 221
 222     if (record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND | EH_NESTED_CALL))
 223         return ExceptionContinueSearch;
 224     if (wine_frame->u.filter)
 225     {
 226         EXCEPTION_POINTERS ptrs;
 227         ptrs.ExceptionRecord = record;
 228         ptrs.ContextRecord = context;
 229         switch(wine_frame->u.filter( &ptrs ))
 230         {
 231         case EXCEPTION_CONTINUE_SEARCH:
 232             return ExceptionContinueSearch;
 233         case EXCEPTION_CONTINUE_EXECUTION:
 234             return ExceptionContinueExecution;
 235         case EXCEPTION_EXECUTE_HANDLER:
 236             break;
 237         default:
 238             MESSAGE( "Invalid return value from exception filter\n" );
 239             assert( FALSE );
 240         }
 241     }
 242     /* hack to make GetExceptionCode() work in handler */
 243     wine_frame->ExceptionCode   = record->ExceptionCode;
 244     wine_frame->ExceptionRecord = wine_frame;
 245
 246     RtlUnwind( frame, 0, record, 0 );
 247     EXC_pop_frame( frame );
 248     longjmp( wine_frame->jmp, 1 );
 249 }
 250
 251
 252 /*************************************************************
 253  *            WINE_finally_handler
 254  *
 255  * Exception handler for try/finally blocks declared in Wine code.
 256  */
 257 DWORD WINE_finally_handler( EXCEPTION_RECORD *record, EXCEPTION_FRAME *frame,
 258                             CONTEXT *context, LPVOID pdispatcher )
 259 {
 260     __WINE_FRAME *wine_frame = (__WINE_FRAME *)frame;
 261
 262     if (!(record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)))
 263         return ExceptionContinueSearch;
 264     wine_frame->u.finally_func( FALSE );
 265     return ExceptionContinueSearch;
 266 }