0,0 → 1,63 |
/* 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(struct rmod_props far *rmod) { |
unsigned short rmodseg = rmod->rmodseg; |
unsigned long *myparent = (void *)0x0A; |
unsigned short far *rmodenv_ptr = MK_FP(rmodseg, RMOD_OFFSET_ENVSEG); |
unsigned short rmodenv = *rmodenv_ptr; |
|
/* detect "I am the origin shell" situations */ |
if (rmod->flags & FLAG_PERMANENT) return; /* COMMAND.COM /P */ |
if ((rmod->origparent >> 16) == 0xffff) return; /* original parent seg set to 0xffff (DOS-C / FreeDOS) */ |
if (rmod->origenvseg == 0) return; /* no original environment (MSDOS 5/6) */ |
|
/* set my parent back to original value */ |
*myparent = rmod->origparent; |
|
_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 |
} |
} |