/* * 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 when * 32-bit code calls relay. */ 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 * * If context is using 32-bit stack or code segment, allocate * 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 ) { if (IS_SELECTOR_32BIT(context->SegCs) || IS_SELECTOR_32BIT(context->SegSs)) { 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 ) { 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; } /********************************************************************** * 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 ) { /* * Make sure that CS and SS are 16-bit. */ 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; /* * Make sure that CS and SS are 16-bit. */ 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; }