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     if (req->status == DBG_CONTINUE) return EXCEPTION_CONTINUE_EXECUTION;
  88
  89     if (pdb->top_filter)
  90     {
  91         DWORD ret = pdb->top_filter( epointers );
  92         if (ret != EXCEPTION_CONTINUE_SEARCH) return ret;
  93     }
  94
  95     /* FIXME: Should check the current error mode */
  96
  97     if (!RegOpenKeyA(HKEY_LOCAL_MACHINE,
  98                      "Software\\Microsoft\\Windows NT\\CurrentVersion\\AeDebug",
  99                      &hDbgConf)) {
 100        DWORD    type;
 101        DWORD    count;
 102
 103        count = sizeof(format);
 104        if (RegQueryValueExA(hDbgConf, "Debugger", 0, &type, format, &count))
 105           format[0] = 0;
 106
 107        count = sizeof(bAuto);
 108        if (RegQueryValueExA(hDbgConf, "Auto", 0, &type, (char*)&bAuto, &count))
 109           bAuto = FALSE;
 110
 111        RegCloseKey(hDbgConf);
 112     } else {
 113        /* format[0] = 0; */
 114        strcpy(format, "debugger/winedbg %ld %ld");
 115     }
 116
 117     if (!bAuto && Callout.MessageBoxA) {
 118        sprintf( buffer, "Unhandled exception 0x%08lx at address 0x%08lx.\n"
 119                         "Do you wish to debug it ?",
 120                 epointers->ExceptionRecord->ExceptionCode,
 121                 (DWORD)epointers->ExceptionRecord->ExceptionAddress );
 122        if (Callout.MessageBoxA( 0, buffer, "Error", MB_YESNO | MB_ICONHAND ) == IDNO) {
 123           TRACE("Killing process\n");
 124           return EXCEPTION_EXECUTE_HANDLER;
 125        }
 126     }
 127
 128     if (format[0]) {
 129        HANDLE                   hEvent;
 130        PROCESS_INFORMATION      info;
 131        STARTUPINFOA             startup;
 132
 133        TRACE("Starting debugger (fmt=%s)\n", format);
 134        hEvent = ConvertToGlobalHandle(CreateEventA(NULL, FALSE, FALSE, NULL));
 135        sprintf(buffer, format, GetCurrentProcessId(), hEvent);
 136        memset(&startup, 0, sizeof(startup));
 137        startup.cb = sizeof(startup);
 138        startup.dwFlags = STARTF_USESHOWWINDOW;
 139        startup.wShowWindow = SW_SHOWNORMAL;
 140        if (CreateProcessA(NULL, buffer, NULL, NULL,
 141                           TRUE, 0, NULL, NULL, &startup, &info)) {
 142           WaitForSingleObject(hEvent, INFINITE);
 143           ret = EXCEPTION_CONTINUE_SEARCH;
 144        } else {
 145           ERR("Couldn't start debugger (%s)\n", buffer);
 146        }
 147        CloseHandle(hEvent);
 148     } else {
 149        ERR("No standard debugger defined in the registry => no debugging session\n");
 150     }
 151
 152     return ret;
 153 }
 154
 155
 156 /***********************************************************************
 157  *            SetUnhandledExceptionFilter   (KERNEL32.516)
 158  */
 159 LPTOP_LEVEL_EXCEPTION_FILTER WINAPI SetUnhandledExceptionFilter(
 160                                           LPTOP_LEVEL_EXCEPTION_FILTER filter )
 161 {
 162     PDB *pdb = PROCESS_Current();
 163     LPTOP_LEVEL_EXCEPTION_FILTER old = pdb->top_filter;
 164     pdb->top_filter = filter;
 165     return old;
 166 }
 167
 168
 169 /**************************************************************************
 170  *           FatalAppExit16   (KERNEL.137)
 171  */
 172 void WINAPI FatalAppExit16( UINT16 action, LPCSTR str )
 173 {
 174     WARN("AppExit\n");
 175     FatalAppExitA( action, str );
 176 }
 177
 178
 179 /**************************************************************************
 180  *           FatalAppExitA   (KERNEL32.108)
 181  */
 182 void WINAPI FatalAppExitA( UINT action, LPCSTR str )
 183 {
 184     WARN("AppExit\n");
 185     Callout.MessageBoxA( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 186     ExitProcess(0);
 187 }
 188
 189
 190 /**************************************************************************
 191  *           FatalAppExitW   (KERNEL32.109)
 192  */
 193 void WINAPI FatalAppExitW( UINT action, LPCWSTR str )
 194 {
 195     WARN("AppExit\n");
 196     Callout.MessageBoxW( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 197     ExitProcess(0);
 198 }
 199
 200
 201 /*************************************************************
 202  *            WINE_exception_handler
 203  *
 204  * Exception handler for exception blocks declared in Wine code.
 205  */
 206 DWORD WINE_exception_handler( EXCEPTION_RECORD *record, EXCEPTION_FRAME *frame,
 207                               CONTEXT *context, LPVOID pdispatcher )
 208 {
 209     __WINE_FRAME *wine_frame = (__WINE_FRAME *)frame;
 210
 211     if (record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND | EH_NESTED_CALL))
 212         return ExceptionContinueSearch;
 213     if (wine_frame->u.filter)
 214     {
 215         EXCEPTION_POINTERS ptrs;
 216         ptrs.ExceptionRecord = record;
 217         ptrs.ContextRecord = context;
 218         switch(wine_frame->u.filter( &ptrs ))
 219         {
 220         case EXCEPTION_CONTINUE_SEARCH:
 221             return ExceptionContinueSearch;
 222         case EXCEPTION_CONTINUE_EXECUTION:
 223             return ExceptionContinueExecution;
 224         case EXCEPTION_EXECUTE_HANDLER:
 225             break;
 226         default:
 227             MESSAGE( "Invalid return value from exception filter\n" );
 228             assert( FALSE );
 229         }
 230     }
 231     /* hack to make GetExceptionCode() work in handler */
 232     wine_frame->ExceptionCode   = record->ExceptionCode;
 233     wine_frame->ExceptionRecord = wine_frame;
 234
 235     RtlUnwind( frame, 0, record, 0 );
 236     EXC_pop_frame( frame );
 237     longjmp( wine_frame->jmp, 1 );
 238 }
 239
 240
 241 /*************************************************************
 242  *            WINE_finally_handler
 243  *
 244  * Exception handler for try/finally blocks declared in Wine code.
 245  */
 246 DWORD WINE_finally_handler( EXCEPTION_RECORD *record, EXCEPTION_FRAME *frame,
 247                             CONTEXT *context, LPVOID pdispatcher )
 248 {
 249     __WINE_FRAME *wine_frame = (__WINE_FRAME *)frame;
 250
 251     if (!(record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)))
 252         return ExceptionContinueSearch;
 253     wine_frame->u.finally_func( FALSE );
 254     return ExceptionContinueSearch;
 255 }