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cons.c
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cons.c
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/* $NetBSD: cons.c,v 1.77 2019/12/06 04:15:38 riastradh Exp $ */
/*
* Copyright (c) 1988 University of Utah.
* Copyright (c) 1990, 1993
* 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. 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: Utah $Hdr: cons.c 1.7 92/01/21$
*
* @(#)cons.c 8.2 (Berkeley) 1/12/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cons.c,v 1.77 2019/12/06 04:15:38 riastradh Exp $");
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/ioctl.h>
#include <sys/poll.h>
#include <sys/tty.h>
#include <sys/file.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/kauth.h>
#include <sys/mutex.h>
#include <dev/cons.h>
#include "nullcons.h"
dev_type_open(cnopen);
dev_type_close(cnclose);
dev_type_read(cnread);
dev_type_write(cnwrite);
dev_type_ioctl(cnioctl);
dev_type_poll(cnpoll);
dev_type_kqfilter(cnkqfilter);
static bool cn_redirect(dev_t *, int, int *);
const struct cdevsw cons_cdevsw = {
.d_open = cnopen,
.d_close = cnclose,
.d_read = cnread,
.d_write = cnwrite,
.d_ioctl = cnioctl,
.d_stop = nostop,
.d_tty = notty,
.d_poll = cnpoll,
.d_mmap = nommap,
.d_kqfilter = cnkqfilter,
.d_discard = nodiscard,
.d_flag = D_TTY
};
struct tty *constty = NULL; /* virtual console output device */
struct consdev *cn_tab; /* physical console device info */
struct vnode *cn_devvp[2]; /* vnode for underlying device. */
int
cnopen(dev_t dev, int flag, int mode, struct lwp *l)
{
dev_t cndev;
int unit, error;
unit = minor(dev);
if (unit > 1)
return ENODEV;
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.
*/
cndev = cn_tab->cn_dev;
#if NNULLCONS > 0
if (cndev == NODEV) {
nullconsattach(0);
}
#else /* NNULLCONS > 0 */
if (cndev == NODEV) {
/*
* This is most likely an error in the console attach
* code. Panicking looks better than jumping into nowhere
* through cdevsw below....
*/
panic("cnopen: no console device");
}
#endif /* NNULLCONS > 0 */
if (dev == cndev) {
/*
* This causes cnopen() to be called recursively, which
* is generally a bad thing. It is often caused when
* dev == 0 and cn_dev has not been set, but was probably
* initialised to 0.
*/
panic("cnopen: cn_tab->cn_dev == dev");
}
if (cn_devvp[unit] != NULLVP)
return 0;
if ((error = cdevvp(cndev, &cn_devvp[unit])) != 0)
printf("cnopen: unable to get vnode reference\n");
error = vn_lock(cn_devvp[unit], LK_EXCLUSIVE | LK_RETRY);
if (error == 0) {
error = VOP_OPEN(cn_devvp[unit], flag, kauth_cred_get());
VOP_UNLOCK(cn_devvp[unit]);
}
return error;
}
int
cnclose(dev_t dev, int flag, int mode, struct lwp *l)
{
struct vnode *vp;
int unit, error;
unit = minor(dev);
if (cn_tab == NULL)
return (0);
vp = cn_devvp[unit];
cn_devvp[unit] = NULL;
error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
if (error == 0) {
error = VOP_CLOSE(vp, flag, kauth_cred_get());
VOP_UNLOCK(vp);
vrele(vp);
}
return error;
}
int
cnread(dev_t dev, struct uio *uio, int flag)
{
int error;
/*
* 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 (!cn_redirect(&dev, 1, &error))
return error;
return cdev_read(dev, uio, flag);
}
int
cnwrite(dev_t dev, struct uio *uio, int flag)
{
int error;
/* Redirect output, if that's appropriate. */
if (!cn_redirect(&dev, 0, &error))
return error;
return cdev_write(dev, uio, flag);
}
int
cnioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
int error;
error = 0;
/*
* Superuser can always use this to wrest control of console
* output from the "virtual" console.
*/
if (cmd == TIOCCONS && constty != NULL) {
error = kauth_authorize_device_tty(l->l_cred,
KAUTH_DEVICE_TTY_VIRTUAL, constty);
if (!error)
constty = NULL;
return (error);
}
/*
* 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 (!cn_redirect(&dev, 0, &error))
return error;
return cdev_ioctl(dev, cmd, data, flag, l);
}
/*ARGSUSED*/
int
cnpoll(dev_t dev, int events, struct lwp *l)
{
int error;
/*
* Redirect the poll, if that's appropriate.
* I don't want to think of the possible side effects
* of console redirection here.
*/
if (!cn_redirect(&dev, 0, &error))
return POLLHUP;
return cdev_poll(dev, events, l);
}
/*ARGSUSED*/
int
cnkqfilter(dev_t dev, struct knote *kn)
{
int error;
/*
* Redirect the kqfilter, if that's appropriate.
* I don't want to think of the possible side effects
* of console redirection here.
*/
if (!cn_redirect(&dev, 0, &error))
return error;
return cdev_kqfilter(dev, kn);
}
int
cngetc(void)
{
if (cn_tab == NULL)
return (0);
int s = splhigh();
for (;;) {
const int rv = (*cn_tab->cn_getc)(cn_tab->cn_dev);
if (rv >= 0) {
splx(s);
return rv;
}
docritpollhooks();
}
}
int
cngetsn(char *cp, int size)
{
char *lp;
int c, len;
cnpollc(1);
lp = cp;
len = 0;
for (;;) {
c = cngetc();
switch (c) {
case '\n':
case '\r':
printf("\n");
*lp++ = '\0';
cnpollc(0);
return (len);
case '\b':
case '\177':
case '#':
if (len) {
--len;
--lp;
printf("\b \b");
}
continue;
case '@':
case 'u'&037: /* CTRL-u */
len = 0;
lp = cp;
printf("\n");
continue;
default:
if (len + 1 >= size || c < ' ') {
printf("\007");
continue;
}
printf("%c", c);
++len;
*lp++ = c;
}
}
}
void
cnputc(int c)
{
if (cn_tab == NULL)
return;
/*
* XXX
* for some reason this causes ARCS firmware to output an endless stream of
* whitespaces with n32 kernels, so use the pre-1.74 code for now until I can
* figure out why this happens
*/
#ifndef sgimips
if (c) {
if (c == '\n') {
(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
docritpollhooks();
}
(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
}
#else
if (c) {
(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
if (c == '\n') {
docritpollhooks();
(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
}
}
#endif
}
void
cnpollc(int on)
{
static int refcount = 0;
if (cn_tab == NULL)
return;
if (!on)
--refcount;
if (refcount == 0)
(*cn_tab->cn_pollc)(cn_tab->cn_dev, on);
if (on)
++refcount;
}
void
nullcnpollc(dev_t dev, int on)
{
}
void
cnbell(u_int pitch, u_int period, u_int volume)
{
if (cn_tab == NULL || cn_tab->cn_bell == NULL)
return;
(*cn_tab->cn_bell)(cn_tab->cn_dev, pitch, period, volume);
}
void
cnflush(void)
{
if (cn_tab == NULL || cn_tab->cn_flush == NULL)
return;
(*cn_tab->cn_flush)(cn_tab->cn_dev);
}
void
cnhalt(void)
{
if (cn_tab == NULL || cn_tab->cn_halt == NULL)
return;
(*cn_tab->cn_halt)(cn_tab->cn_dev);
}
/*
* Redirect output, if that's appropriate. If there's no real console,
* return ENXIO.
*
* Call with tty_mutex held.
*/
static bool
cn_redirect(dev_t *devp, int is_read, int *error)
{
dev_t dev = *devp;
*error = ENXIO;
if (constty != NULL && minor(dev) == 0 &&
(cn_tab == NULL || (cn_tab->cn_pri != CN_REMOTE))) {
if (is_read) {
*error = 0;
return false;
}
dev = constty->t_dev;
} else if (cn_tab == NULL)
return false;
else
dev = cn_tab->cn_dev;
*devp = dev;
return true;
}