Sweden-Number/dlls/winedos/relay.c

270 lines
8.8 KiB
C
Raw Normal View History

/*
* 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 "stackframe.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 *context )
{
if (proc)
proc( (CONTEXT86*)context, *(LPVOID *)args );
}
/**********************************************************************
* 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;
/*
* We have now restored original stack and instruction pointers.
* Because signals are blocked here, this is a safe place to
* check for pending events before we return to application context.
*/
if (NtCurrentTeb()->vm86_pending && NtCurrentTeb()->dpmi_vif)
{
NtCurrentTeb()->vm86_pending = 0;
DOSVM_SendQueuedEvents( context );
}
}
/**********************************************************************
* DOSVM_SaveCallFrame
*
* Save current call frame. This routine must be called from DOSRELAY
* called using DOSVM_BuildCallFrame before the relay modifies stack
* pointer. This routine makes sure that the relay can return safely
* to application context and that no memory is leaked.
*
* Note: If DOSVM_BuildCallFrame was called using 32-bit CS or SS,
* old values of CS and SS will be lost. This does not matter
* since this routine is only used by Raw Mode Switch.
*/
void DOSVM_SaveCallFrame( CONTEXT86 *context, STACK16FRAME *frame )
{
*frame = *CURRENT_STACK16;
/*
* If context is using allocated stack, release it.
*/
if (context->SegSs == DOSVM_dpmi_segments->relay_data_sel)
{
RELAY_Stack16 *stack = RELAY_GetPointer( context->Esp );
if (!stack->inuse ||
stack->stack_bottom != RELAY_MAGIC ||
stack->stack_top != RELAY_MAGIC)
ERR( "Stack corrupted!\n" );
stack->inuse = 0;
}
}
/**********************************************************************
* DOSVM_RestoreCallFrame
*
* Restore saved call frame to currect stack. This routine must always
* be called after DOSVM_SaveCallFrame has been called and before returning
* from DOSRELAY.
*/
void DOSVM_RestoreCallFrame( CONTEXT86 *context, STACK16FRAME *frame )
{
/*
* Allocate separate stack for relay call.
*/
RELAY_MakeShortContext( context );
/*
* After this function returns to relay code, protected mode
* 16 bit stack will contain STACK16FRAME and single WORD
* (EFlags, see next comment).
*/
NtCurrentTeb()->cur_stack =
MAKESEGPTR( context->SegSs,
context->Esp - sizeof(STACK16FRAME) - sizeof(WORD) );
/*
* After relay code returns to glue function, protected
* mode 16 bit stack will contain interrupt return record:
* IP, CS and EFlags. Since EFlags is ignored, it won't
* need to be initialized.
*/
context->Esp -= 3 * sizeof(WORD);
/*
* Restore stack frame so that relay code won't be confused.
* It should be noted that relay code overwrites IP and CS
* in STACK16FRAME with values taken from current CONTEXT86.
* These values are what is returned to glue function
* (see previous comment).
*/
*CURRENT_STACK16 = *frame;
}
/**********************************************************************
* 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 *stack;
WORD code_sel = DOSVM_dpmi_segments->relay_code_sel;
/*
* Allocate separate stack for relay call.
*/
RELAY_MakeShortContext( context );
/*
* Get stack pointer after RELAY_MakeShortContext.
*/
stack = CTX_SEG_OFF_TO_LIN(context, context->SegSs, context->Esp);
/*
* Build call frame.
*/
*(--stack) = HIWORD(data); /* argument.hiword */
*(--stack) = LOWORD(data); /* argument.loword */
*(--stack) = context->SegCs; /* STACK16FRAME.cs */
*(--stack) = LOWORD(context->Eip); /* STACK16FRAME.ip */
*(--stack) = LOWORD(context->Ebp); /* STACK16FRAME.bp */
*(--stack) = HIWORD(relay); /* STACK16FRAME.entry_point.hiword */
*(--stack) = LOWORD(relay); /* STACK16FRAME.entry_point.loword */
*(--stack) = 0; /* STACK16FRAME.entry_ip */
*(--stack) = HIWORD(RELAY_RelayStub); /* STACK16FRAME.relay.hiword */
*(--stack) = LOWORD(RELAY_RelayStub); /* STACK16FRAME.relay.loword */
*(--stack) = 0; /* STACK16FRAME.module_cs.hiword */
*(--stack) = code_sel; /* STACK16FRAME.module_cs.loword */
*(--stack) = 0; /* STACK16FRAME.callfrom_ip.hiword */
*(--stack) = 0; /* STACK16FRAME.callfrom_ip.loword */
/*
* Adjust stack and code pointers.
*/
ADD_LOWORD( context->Esp, -28 );
context->SegCs = wine_get_cs();
context->Eip = (DWORD)__wine_call_from_16_regs;
}