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