FreeDOS/kernel/break.c
Bart Oldeman f94ba5ebe1 Improve ^C handling:
- ^C didn't work for int21/ah=3f. Corrected -- Do_DosIdle_loop still needs
  to wait even if it doesn't call the idle int
- ^C needs to be echoed to STDOUT for low character functions (ah<0xd) but
  to the device that is read from for handle functions. So we need to pass
  either the STDOUT sft or that device on to the ^C echoer.
- The ^C echo really should print ^C\r\n.
- misc cleanups in break.c.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@883 6ac86273-5f31-0410-b378-82cca8765d1b
2004-04-14 09:20:08 +00:00

79 lines
3.0 KiB
C

/****************************************************************/
/* */
/* break.c */
/* FreeDOS */
/* */
/* Control Break detection and handling */
/* */
/* Copyright (c) 1999 */
/* Steffen Kaiser */
/* All Rights Reserved */
/* */
/* This file is part of DOS-C. */
/* */
/* DOS-C is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU General Public License */
/* as published by the Free Software Foundation; either version */
/* 2, or (at your option) any later version. */
/* */
/* DOS-C 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 General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public */
/* License along with DOS-C; see the file COPYING. If not, */
/* write to the Free Software Foundation, 675 Mass Ave, */
/* Cambridge, MA 02139, USA. */
/****************************************************************/
#include "portab.h"
#include "globals.h"
#include "proto.h"
#ifdef VERSION_STRINGS
static BYTE *RcsId =
"$Id$";
#endif
#define CB_FLG *(UBYTE FAR*)MK_FP(0x0, 0x471)
#define CB_MSK 0x80
/* Check for ^Break/^C.
* Three sources are available:
* 1) flag at 40:71 bit 7
* 2) CON stream (if STDIN is redirected somewhere else)
* 3) input stream (most likely STDIN)
* Actions:
* 1) echo ^C
* 2) clear the STDIN stream
* 3) decrease the InDOS flag as the kernel drops back to user space
* 4) invoke INT-23 and never come back
*/
unsigned char check_handle_break(struct dhdr FAR **pdev, int sft_out)
{
unsigned char c = CTL_C;
if (CB_FLG & CB_MSK)
CB_FLG &= ~CB_MSK; /* reset the ^Break flag */
else
c = (unsigned char)ndread(&syscon);
if (c == CTL_C)
{
sft_out = -1;
pdev = &syscon;
}
else if (*pdev != syscon)
c = (unsigned char)ndread(pdev);
if (c == CTL_C)
{
con_flush(pdev);
echo_ctl_c(pdev, sft_out);
if (!ErrorMode) /* within int21_handler, InDOS is not incremented */
if (InDOS)
--InDOS; /* fail-safe */
spawn_int23(); /* invoke user INT-23 and never come back */
}
return c;
}