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/* This file is part of the SvarCOM project and is published under the terms
* of the MIT license.
*
* Copyright (C) 2021 Mateusz Viste
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <i86.h>
#include "rmodinit.h"
#include "sayonara.h"
/* rewires my parent pointer, uninstalls rmod let DOS terminate me, UNLESS
* my parent is unknown */
void sayonara(unsigned short rmodseg) {
unsigned long far *orgparent = MK_FP(rmodseg, RMOD_OFFSET_ORIGPARENT);
unsigned long *myparent = (void *)0x0A;
unsigned short far *rmodenv_ptr = MK_FP(rmodseg, RMOD_OFFSET_ENVSEG);
unsigned short rmodenv = *rmodenv_ptr;
/* set my parent back to original value (if 0 = shell is permanent) */
if (*orgparent == 0) return;
*myparent = *orgparent;
_asm {
/* free RMOD's code segment and env segment */
mov ah, 0x49 /* DOS 2+ -- Free Memory Block */
mov es, [rmodseg]
int 0x21
/* free RMOD's env segment */
mov ah, 0x49 /* DOS 2+ -- Free Memory Block */
mov es, [rmodenv]
int 0x21
/* gameover */
mov ax, 0x4C00 /* DOS 2+ -- Terminate with exit code 0 */
int 0x21
}
}