Sweden-Number/dlls/winedos/relay.c

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/*
* Routines for dynamically building calls to Wine from
* protected mode applications.
*
* Copyright 2002 Jukka Heinonen
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "dosexe.h"
#include "thread.h"
#include "wine/debug.h"
#include "builtin16.h"
WINE_DEFAULT_DEBUG_CHANNEL(int);
/*
* Magic DWORD used to check stack integrity.
*/
#define RELAY_MAGIC 0xabcdef00
/*
* Memory block for temporary 16-bit stacks used with relay calls.
*/
typedef struct {
DWORD inuse; /* non-zero if stack block is in use */
DWORD eip; /* saved ip */
DWORD seg_cs; /* saved cs */
DWORD esp; /* saved sp */
DWORD seg_ss; /* saved ss */
DWORD stack_bottom; /* guard dword */
BYTE stack[256-7*4]; /* 16-bit stack */
DWORD stack_top; /* guard dword */
} RELAY_Stack16;
/**********************************************************************
* RELAY_GetPointer
*
* Get pointer to stack block when given esp pointing to 16-bit stack
* inside relay data segment.
*/
static RELAY_Stack16 *RELAY_GetPointer( DWORD offset )
{
offset = offset / sizeof(RELAY_Stack16) * sizeof(RELAY_Stack16);
return MapSL(MAKESEGPTR(DOSVM_dpmi_segments->relay_data_sel, offset));
}
/**********************************************************************
* RELAY_MakeShortContext
*
* Allocate separate 16-bit stack, make stack pointer point to this
* stack and make code pointer point to stub that restores everything.
* So, after this routine, SS and CS are guaranteed to be 16-bit.
*
* Note: This might be called from signal handler, so the stack
* allocation algorithm must be signal safe.
*/
static void RELAY_MakeShortContext( CONTEXT86 *context )
{
DWORD offset = offsetof(RELAY_Stack16, stack_top);
RELAY_Stack16 *stack = RELAY_GetPointer( 0 );
while (stack->inuse && offset < DOSVM_RELAY_DATA_SIZE) {
stack++;
offset += sizeof(RELAY_Stack16);
}
if (offset >= DOSVM_RELAY_DATA_SIZE)
ERR( "Too many nested interrupts!\n" );
stack->inuse = 1;
stack->eip = context->Eip;
stack->seg_cs = context->SegCs;
stack->esp = context->Esp;
stack->seg_ss = context->SegSs;
stack->stack_bottom = RELAY_MAGIC;
stack->stack_top = RELAY_MAGIC;
context->SegSs = DOSVM_dpmi_segments->relay_data_sel;
context->Esp = offset;
context->SegCs = DOSVM_dpmi_segments->relay_code_sel;
context->Eip = 3;
}
/**********************************************************************
* RELAY_RelayStub
*
* This stub is called by __wine_call_from_16_regs in order to marshall
* relay parameters.
*/
static void __stdcall RELAY_RelayStub( DOSRELAY proc,
unsigned char *args,
void *ctx86 )
{
if (proc)
{
CONTEXT86 *context = (CONTEXT86*)ctx86;
RELAY_Stack16 *stack = RELAY_GetPointer( context->Esp );
DWORD old_seg_cs = context->SegCs;
DWORD old_eip = context->Eip;
DWORD old_seg_ss = context->SegSs;
DWORD old_esp = context->Esp;
context->SegCs = stack->seg_cs;
context->Eip = stack->eip;
context->SegSs = stack->seg_ss;
context->Esp = stack->esp;
proc( context, *(LPVOID *)args );
stack->seg_cs = context->SegCs;
stack->eip = context->Eip;
stack->seg_ss = context->SegSs;
stack->esp = context->Esp;
context->SegCs = old_seg_cs;
context->Eip = old_eip;
context->SegSs = old_seg_ss;
context->Esp = old_esp;
}
}
/**********************************************************************
* DOSVM_RelayHandler
*
* Restore saved code and stack pointers and release stack block.
*/
void DOSVM_RelayHandler( CONTEXT86 *context )
{
RELAY_Stack16 *stack = RELAY_GetPointer( context->Esp );
context->SegSs = stack->seg_ss;
context->Esp = stack->esp;
context->SegCs = stack->seg_cs;
context->Eip = stack->eip;
if (!stack->inuse ||
stack->stack_bottom != RELAY_MAGIC ||
stack->stack_top != RELAY_MAGIC)
ERR( "Stack corrupted!\n" );
stack->inuse = 0;
}
/**********************************************************************
* DOSVM_BuildCallFrame
*
* Modifies the context so that return to context calls DOSRELAY and
* only after return from DOSRELAY the original context will be returned to.
*/
void DOSVM_BuildCallFrame( CONTEXT86 *context, DOSRELAY relay, LPVOID data )
{
WORD code_sel = DOSVM_dpmi_segments->relay_code_sel;
/*
* Allocate separate stack for relay call.
*/
RELAY_MakeShortContext( context );
/*
* Build call frame.
*/
PUSH_WORD16( context, HIWORD(data) ); /* argument.hiword */
PUSH_WORD16( context, LOWORD(data) ); /* argument.loword */
PUSH_WORD16( context, context->SegCs ); /* STACK16FRAME.cs */
PUSH_WORD16( context, LOWORD(context->Eip) ); /* STACK16FRAME.ip */
PUSH_WORD16( context, LOWORD(context->Ebp) ); /* STACK16FRAME.bp */
PUSH_WORD16( context, HIWORD(relay) ); /* STACK16FRAME.entry_point.hiword */
PUSH_WORD16( context, LOWORD(relay) ); /* STACK16FRAME.entry_point.loword */
PUSH_WORD16( context, 0 ); /* STACK16FRAME.entry_ip */
PUSH_WORD16( context, HIWORD(RELAY_RelayStub) ); /* STACK16FRAME.relay.hiword */
PUSH_WORD16( context, LOWORD(RELAY_RelayStub) ); /* STACK16FRAME.relay.loword */
PUSH_WORD16( context, 0 ); /* STACK16FRAME.module_cs.hiword */
PUSH_WORD16( context, code_sel ); /* STACK16FRAME.module_cs.loword */
PUSH_WORD16( context, 0 ); /* STACK16FRAME.callfrom_ip.hiword */
PUSH_WORD16( context, 0 ); /* STACK16FRAME.callfrom_ip.loword */
/*
* Adjust code pointer.
*/
context->SegCs = wine_get_cs();
context->Eip = (DWORD)__wine_call_from_16_regs;
}