freebsd-nq/sys/kern/tty_cons.c
Joerg Wunsch 4fb0b0de3e Implement a simple hook (or hack?) to allow graphics device console
drivers to protect DDB from being invoked while the console is in
process-controlled (i.e., graphics) mode.

Implement the logic to use this hook from within pcvt.  (I'm sure
Søren will do the syscons part RSN).

I've still got one occasion where the system stalled, but my attempts
to trigger the situation artificially resulted int the expected
behaviour.  It's hard to track bugs without the console and DDB
available. :-/
1995-04-08 21:32:11 +00:00

291 lines
6.8 KiB
C

/*
* Copyright (c) 1988 University of Utah.
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)cons.c 7.2 (Berkeley) 5/9/91
* $Id: cons.c,v 1.24 1995/04/02 16:14:51 joerg Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/tty.h>
#include <machine/cons.h>
#include <machine/stdarg.h>
/* XXX - all this could be autoconfig()ed */
#include "sc.h"
#include "vt.h"
#if NSC > 0 || NVT > 0
int pccnprobe(), pccninit(), pccngetc(), pccncheckc(), pccnputc();
#endif
#include "sio.h"
#if NSIO > 0
int siocnprobe(), siocninit(), siocngetc(), siocncheckc(), siocnputc();
#endif
static struct consdev constab[] = {
#if NSC > 0 || NVT > 0
{ pccnprobe, pccninit, pccngetc, pccncheckc, pccnputc },
#endif
#if NSIO > 0
{ siocnprobe, siocninit, siocngetc, siocncheckc, siocnputc },
#endif
{ 0 },
};
/* end XXX */
struct tty *constty = 0; /* virtual console output device */
struct tty *cn_tty; /* XXX: console tty struct for tprintf */
int cons_unavail = 0; /* XXX:
* physical console not available for
* input (i.e., it is in graphics mode)
*/
static u_char cn_is_open; /* nonzero if logical console is open */
static u_char cn_phys_is_open; /* nonzero if physical console is open */
static d_close_t *cn_phys_close; /* physical device close function */
static d_open_t *cn_phys_open; /* physical device open function */
static struct consdev *cn_tab; /* physical console device info */
static struct tty *cn_tp; /* physical console tty struct */
void
cninit()
{
register struct consdev *cp;
struct cdevsw *cdp;
/*
* Collect information about all possible consoles
* and find the one with highest priority
*/
for (cp = constab; cp->cn_probe; cp++) {
(*cp->cn_probe)(cp);
if (cp->cn_pri > CN_DEAD &&
(cn_tab == NULL || cp->cn_pri > cn_tab->cn_pri))
cn_tab = cp;
}
/*
* No console, give up.
*/
if ((cp = cn_tab) == NULL)
return;
/*
* Hook the open and close functions.
*/
cdp = &cdevsw[major(cn_tab->cn_dev)];
cn_phys_close = cdp->d_close;
cdp->d_close = cnclose;
cn_phys_open = cdp->d_open;
cdp->d_open = cnopen;
cn_tp = (*cdp->d_devtotty)(cn_tab->cn_dev);
/*
* Turn on console
*/
cn_tty = cp->cn_tp;
(*cp->cn_init)(cp);
}
int
cnopen(dev, flag, mode, p)
dev_t dev;
int flag, mode;
struct proc *p;
{
dev_t cndev, physdev;
int retval;
if (cn_tab == NULL)
return (0);
cndev = cn_tab->cn_dev;
physdev = (major(dev) == major(cndev) ? dev : cndev);
retval = (*cn_phys_open)(physdev, flag, mode, p);
if (retval == 0) {
if (dev == cndev)
cn_phys_is_open = 1;
else if (physdev == cndev)
cn_is_open = 1;
}
return (retval);
}
int
cnclose(dev, flag, mode, p)
dev_t dev;
int flag, mode;
struct proc *p;
{
dev_t cndev;
if (cn_tab == NULL)
return (0);
cndev = cn_tab->cn_dev;
if (dev == cndev) {
/* the physical device is about to be closed */
cn_phys_is_open = 0;
if (cn_is_open) {
if (cn_tp) {
/* perform a ttyhalfclose() */
/* reset session and proc group */
cn_tp->t_pgrp = NULL;
cn_tp->t_session = NULL;
}
return (0);
}
} else if (major(dev) != major(cndev)) {
/* the logical console is about to be closed */
cn_is_open = 0;
if (cn_phys_is_open)
return (0);
dev = cndev;
}
return ((*cn_phys_close)(dev, flag, mode, p));
}
int
cnread(dev, uio, flag)
dev_t dev;
struct uio *uio;
int flag;
{
if (cn_tab == NULL)
return (0);
dev = cn_tab->cn_dev;
return ((*cdevsw[major(dev)].d_read)(dev, uio, flag));
}
int
cnwrite(dev, uio, flag)
dev_t dev;
struct uio *uio;
int flag;
{
if (cn_tab == NULL)
return (0);
if (constty)
dev = constty->t_dev;
else
dev = cn_tab->cn_dev;
return ((*cdevsw[major(dev)].d_write)(dev, uio, flag));
}
int
cnioctl(dev, cmd, data, flag, p)
dev_t dev;
int cmd;
caddr_t data;
int flag;
struct proc *p;
{
int error;
if (cn_tab == NULL)
return (0);
/*
* Superuser can always use this to wrest control of console
* output from the "virtual" console.
*/
if (cmd == TIOCCONS && constty) {
error = suser(p->p_ucred, (u_short *) NULL);
if (error)
return (error);
constty = NULL;
return (0);
}
dev = cn_tab->cn_dev;
return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p));
}
/*ARGSUSED*/
int
cnselect(dev, rw, p)
dev_t dev;
int rw;
struct proc *p;
{
if (cn_tab == NULL)
return (1);
dev = cn_tab->cn_dev;
return ((*cdevsw[major(dev)].d_select)(dev, rw, p));
}
int
cngetc()
{
int c;
if (cn_tab == NULL)
return (0);
c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
if (c == '\r') c = '\n'; /* console input is always ICRNL */
return (c);
}
int
cncheckc()
{
if (cn_tab == NULL)
return (0);
return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
}
void
cnputc(c)
register int c;
{
if (cn_tab == NULL)
return;
if (c) {
(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
if (c == '\n')
(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
}
}
int
pg(const char *p, ...) {
va_list args;
va_start(args, p);
printf("%r\n>", p, args);
return(cngetc());
}