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     char message[80];
  76     PDB *pdb = PROCESS_Current();
  77
  78     /* send a last chance event to the debugger */
  79     req->record  = *epointers->ExceptionRecord;
  80     req->first   = 0;
  81     req->context = *epointers->ContextRecord;
  82     if (!server_call_noerr( REQ_EXCEPTION_EVENT )) *epointers->ContextRecord = req->context;
  83     if (req->status == DBG_CONTINUE) return EXCEPTION_CONTINUE_EXECUTION;
  84
  85     if (pdb->top_filter)
  86     {
  87         DWORD ret = pdb->top_filter( epointers );
  88         if (ret != EXCEPTION_CONTINUE_SEARCH) return ret;
  89     }
  90
  91     /* FIXME: Should check the current error mode */
  92
  93     sprintf( message, "Unhandled exception 0x%08lx at address 0x%08lx.",
  94              epointers->ExceptionRecord->ExceptionCode,
  95              (DWORD)epointers->ExceptionRecord->ExceptionAddress );
  96     Callout.MessageBoxA( 0, message, "Error", MB_OK | MB_ICONHAND );
  97     return EXCEPTION_EXECUTE_HANDLER;
  98 }
  99
 100
 101 /*************************************************************
 102  *            SetUnhandledExceptionFilter   (KERNEL32.516)
 103  */
 104 LPTOP_LEVEL_EXCEPTION_FILTER WINAPI SetUnhandledExceptionFilter(
 105                                           LPTOP_LEVEL_EXCEPTION_FILTER filter )
 106 {
 107     PDB *pdb = PROCESS_Current();
 108     LPTOP_LEVEL_EXCEPTION_FILTER old = pdb->top_filter;
 109     pdb->top_filter = filter;
 110     return old;
 111 }
 112
 113
 114 /**************************************************************************
 115  *           FatalAppExit16   (KERNEL.137)
 116  */
 117 void WINAPI FatalAppExit16( UINT16 action, LPCSTR str )
 118 {
 119     WARN("AppExit\n");
 120     FatalAppExitA( action, str );
 121 }
 122
 123
 124 /**************************************************************************
 125  *           FatalAppExitA   (KERNEL32.108)
 126  */
 127 void WINAPI FatalAppExitA( UINT action, LPCSTR str )
 128 {
 129     WARN("AppExit\n");
 130     Callout.MessageBoxA( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 131     ExitProcess(0);
 132 }
 133
 134
 135 /**************************************************************************
 136  *           FatalAppExitW   (KERNEL32.109)
 137  */
 138 void WINAPI FatalAppExitW( UINT action, LPCWSTR str )
 139 {
 140     WARN("AppExit\n");
 141     Callout.MessageBoxW( 0, str, NULL, MB_SYSTEMMODAL | MB_OK );
 142     ExitProcess(0);
 143 }
 144
 145
 146 /*************************************************************
 147  *            WINE_exception_handler
 148  *
 149  * Exception handler for exception blocks declared in Wine code.
 150  */
 151 DWORD WINE_exception_handler( EXCEPTION_RECORD *record, EXCEPTION_FRAME *frame,
 152                               CONTEXT *context, LPVOID pdispatcher )
 153 {
 154     __WINE_FRAME *wine_frame = (__WINE_FRAME *)frame;
 155
 156     if (record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND | EH_NESTED_CALL))
 157         return ExceptionContinueSearch;
 158     if (wine_frame->u.filter)
 159     {
 160         EXCEPTION_POINTERS ptrs;
 161         ptrs.ExceptionRecord = record;
 162         ptrs.ContextRecord = context;
 163         switch(wine_frame->u.filter( &ptrs ))
 164         {
 165         case EXCEPTION_CONTINUE_SEARCH:
 166             return ExceptionContinueSearch;
 167         case EXCEPTION_CONTINUE_EXECUTION:
 168             return ExceptionContinueExecution;
 169         case EXCEPTION_EXECUTE_HANDLER:
 170             break;
 171         default:
 172             MESSAGE( "Invalid return value from exception filter\n" );
 173             assert( FALSE );
 174         }
 175     }
 176     /* hack to make GetExceptionCode() work in handler */
 177     wine_frame->ExceptionCode   = record->ExceptionCode;
 178     wine_frame->ExceptionRecord = wine_frame;
 179
 180     RtlUnwind( frame, 0, record, 0 );
 181     EXC_pop_frame( frame );
 182     longjmp( wine_frame->jmp, 1 );
 183 }
 184
 185
 186 /*************************************************************
 187  *            WINE_finally_handler
 188  *
 189  * Exception handler for try/finally blocks declared in Wine code.
 190  */
 191 DWORD WINE_finally_handler( EXCEPTION_RECORD *record, EXCEPTION_FRAME *frame,
 192                             CONTEXT *context, LPVOID pdispatcher )
 193 {
 194     __WINE_FRAME *wine_frame = (__WINE_FRAME *)frame;
 195
 196     if (!(record->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)))
 197         return ExceptionContinueSearch;
 198     wine_frame->u.finally_func( FALSE );
 199     return ExceptionContinueSearch;
 200 }