NetBSD/sys/dev/cons.c

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/*
* 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 1.12 1994/02/16 00:09:39 cgd Exp $
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*/
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/file.h>
#include <sys/conf.h>
#include <sys/vnode.h>
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#include <dev/cons.h>
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extern struct consdev constab[];
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struct tty *constty = NULL; /* virtual console output device */
struct consdev *cn_tab; /* physical console device info */
void
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cninit()
{
register struct consdev *cp;
/*
* 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, we can handle it
*/
if ((cp = cn_tab) == NULL)
return;
/*
* Turn on console
*/
(*cp->cn_init)(cp);
}
int
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cnopen(dev, flag, mode, p)
dev_t dev;
int flag, mode;
struct proc *p;
{
if (cn_tab == NULL)
return (0);
/*
* always open the 'real' console device, so we don't get nailed
* later. This follows normal device semantics; they always get
* open() calls.
*/
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dev = cn_tab->cn_dev;
return ((*cdevsw[major(dev)].d_open)(dev, flag, mode, p));
}
int
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cnclose(dev, flag, mode, p)
dev_t dev;
int flag, mode;
struct proc *p;
{
struct vnode *vp;
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if (cn_tab == NULL)
return (0);
/*
* If the real console isn't otherwise open, close it.
* If it's otherwise open, don't close it, because that'll
* screw up others who have it open.
*/
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dev = cn_tab->cn_dev;
if ((vfinddev(dev, VCHR, &vp) == 0) && vcount(vp))
return (0);
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return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p));
}
int
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cnread(dev, uio, flag)
dev_t dev;
struct uio *uio;
{
/*
* If we would redirect input, punt. This will keep strange
* things from happening to people who are using the real
* console. Nothing should be using /dev/console for
* input (except a shell in single-user mode, but then,
* one wouldn't TIOCCONS then).
*/
if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE))
return 0;
else if (cn_tab == NULL)
return ENXIO;
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dev = cn_tab->cn_dev;
return ((*cdevsw[major(dev)].d_read)(dev, uio, flag));
}
int
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cnwrite(dev, uio, flag)
dev_t dev;
struct uio *uio;
{
/*
* Redirect output, if that's appropriate.
* If there's no real console, return ENXIO.
*/
if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE))
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dev = constty->t_dev;
else if (cn_tab == NULL)
return ENXIO;
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else
dev = cn_tab->cn_dev;
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return ((*cdevsw[major(dev)].d_write)(dev, uio, flag));
}
int
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cnioctl(dev, cmd, data, flag, p)
dev_t dev;
caddr_t data;
struct proc *p;
{
int error;
/*
* Superuser can always use this to wrest control of console
* output from the "virtual" console.
*/
if (cmd == TIOCCONS && constty != NULL) {
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error = suser(p->p_ucred, (u_short *) NULL);
if (error)
return (error);
constty = NULL;
return (0);
}
/*
* Redirect the ioctl, if that's appropriate.
* Note that strange things can happen, if a program does
* ioctls on /dev/console, then the console is redirected
* out from under it.
*/
if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE))
dev = constty->t_dev;
else if (cn_tab == NULL)
return ENXIO;
else
dev = cn_tab->cn_dev;
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return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p));
}
/*ARGSUSED*/
int
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cnselect(dev, rw, p)
dev_t dev;
int rw;
struct proc *p;
{
/*
* Redirect the ioctl, if that's appropriate.
* I don't want to think of the possible side effects
* of console redirection here.
*/
if (constty != NULL && (cn_tab == NULL || cn_tab->cn_pri != CN_REMOTE))
dev = constty->t_dev;
else if (cn_tab == NULL)
return ENXIO;
else
dev = cn_tab->cn_dev;
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return (ttselect(cn_tab->cn_dev, rw, p));
}
int
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cngetc()
{
if (cn_tab == NULL)
return (0);
return ((*cn_tab->cn_getc)(cn_tab->cn_dev));
}
int
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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');
}
}