94 lines
3.4 KiB
C
94 lines
3.4 KiB
C
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/****************************************************************/
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/* */
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/* break.c */
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/* FreeDOS */
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/* */
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/* Control Break detection and handling */
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/* */
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/* Copyright (c) 1999 */
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/* Steffen Kaiser */
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/* All Rights Reserved */
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/* */
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/* This file is part of DOS-C. */
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/* */
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/* DOS-C is free software; you can redistribute it and/or */
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/* modify it under the terms of the GNU General Public License */
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/* as published by the Free Software Foundation; either version */
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/* 2, or (at your option) any later version. */
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/* */
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/* DOS-C is distributed in the hope that it will be useful, but */
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/* WITHOUT ANY WARRANTY; without even the implied warranty of */
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/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See */
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/* the GNU General Public License for more details. */
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/* */
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/* You should have received a copy of the GNU General Public */
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/* License along with DOS-C; see the file COPYING. If not, */
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/* write to the Free Software Foundation, 675 Mass Ave, */
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/* Cambridge, MA 02139, USA. */
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/****************************************************************/
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#include "portab.h"
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#include "globals.h"
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#include "proto.h"
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#ifdef VERSION_STRINGS
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static BYTE *RcsId =
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"$Id: break.c 885 2004-04-14 15:40:51Z bartoldeman $";
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#endif
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#define CB_FLG *(UBYTE FAR*)MK_FP(0x0, 0x471)
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#define CB_MSK 0x80
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/* Check for ^Break/^C.
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* Three sources are available:
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* 1) flag at 40:71 bit 7
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* 2) syscon stream (usually CON:)
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* 3) i/o stream (if unequal to syscon, e.g. AUX)
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*/
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unsigned char ctrl_break_pressed(void)
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{
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return CB_FLG & CB_MSK;
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}
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unsigned char check_handle_break(struct dhdr FAR **pdev)
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{
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unsigned char c = CTL_C;
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if (!ctrl_break_pressed())
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c = (unsigned char)ndread(&syscon);
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if (c != CTL_C && *pdev != syscon)
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c = (unsigned char)ndread(pdev);
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if (c == CTL_C)
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handle_break(pdev, -1);
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return c;
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}
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/*
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* Handles a ^Break state
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*
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* Actions:
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* 1) clear the ^Break flag
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* 2) clear the STDIN stream
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* 3) echo ^C to sft_out or pdev if sft_out==-1
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* 4) decrease the InDOS flag as the kernel drops back to user space
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* 5) invoke INT-23 and never come back
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*/
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void handle_break(struct dhdr FAR **pdev, int sft_out)
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{
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char *buf = "^C\r\n";
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CB_FLG &= ~CB_MSK; /* reset the ^Break flag */
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con_flush(pdev);
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if (sft_out == -1)
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cooked_write(pdev, 4, buf);
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else
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DosRWSft(sft_out, 4, buf, XFR_FORCE_WRITE);
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if (!ErrorMode) /* within int21_handler, InDOS is not incremented */
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if (InDOS)
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--InDOS; /* fail-safe */
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spawn_int23(); /* invoke user INT-23 and never come back */
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}
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