Reimplement the /dev/console device node.

One of the pieces of code that I had left alone during the development
of the MPSAFE TTY layer, was tty_cons.c. This file actually has two
different functions:

- It contains low-level console input/output routines (cnputc(), etc).

- It creates /dev/console and wraps all its cdevsw calls to the
  appropriate TTY.

This commit reimplements the second set of functions by moving it
directly into the TTY layer. /dev/console is now a character device node
that's basically a regular TTY, but does a lookup of `si_drv1' each time
you open it. d_write has also been changed to call log_console().
d_close() is not present, because we must make sure we don't revoke the
TTY after writing a log message to it.

Even though I'm not convinced this is in line with the future directions
of our console code, it is a good move for now. It removes recursive
locking from the top half of the TTY layer. The previous implementation
called into the TTY layer with Giant held.

I'm renaming tty_cons.c to kern_cons.c now. The code hardly contains any
TTY related bits, so we'd better give it a less misleading name.

Tested by:	Andrzej Tobola <ato iem pw edu pl>,
		Carlos A.M. dos Santos <unixmania gmail com>,
		Eygene Ryabinkin <rea-fbsd codelabs ru>

1 files changed, 0 insertions, 796 deletions

diff --git a/sys/kern/tty_cons.c b/sys/kern/tty_cons.c
deleted file mode 100644
index 81e1708..0000000
--- a/sys/kern/tty_cons.c
+++ /dev/null
@@ -1,796 +0,0 @@
-/*-
- * 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.
- * 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
- */
-
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-#include "opt_ddb.h"
-
-#include <sys/param.h>
-#include <sys/systm.h>
-#include <sys/lock.h>
-#include <sys/mutex.h>
-#include <sys/conf.h>
-#include <sys/cons.h>
-#include <sys/fcntl.h>
-#include <sys/kdb.h>
-#include <sys/kernel.h>
-#include <sys/malloc.h>
-#include <sys/msgbuf.h>
-#include <sys/namei.h>
-#include <sys/priv.h>
-#include <sys/proc.h>
-#include <sys/queue.h>
-#include <sys/reboot.h>
-#include <sys/sysctl.h>
-#include <sys/sbuf.h>
-#include <sys/tty.h>
-#include <sys/uio.h>
-#include <sys/vnode.h>
-
-#include <ddb/ddb.h>
-
-#include <machine/cpu.h>
-#include <machine/clock.h>
-
-static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
-
-static	d_open_t	cnopen;
-static	d_close_t	cnclose;
-static	d_read_t	cnread;
-static	d_write_t	cnwrite;
-static	d_ioctl_t	cnioctl;
-static	d_poll_t	cnpoll;
-static	d_kqfilter_t	cnkqfilter;
-
-static struct cdevsw cn_cdevsw = {
-	.d_version =	D_VERSION,
-	.d_open =	cnopen,
-	.d_close =	cnclose,
-	.d_read =	cnread,
-	.d_write =	cnwrite,
-	.d_ioctl =	cnioctl,
-	.d_poll =	cnpoll,
-	.d_name =	"console",
-	.d_flags =	D_TTY | D_NEEDGIANT,
-	.d_kqfilter =	cnkqfilter,
-};
-
-struct cn_device {
-	STAILQ_ENTRY(cn_device) cnd_next;
-	struct		vnode *cnd_vp;
-	struct		consdev *cnd_cn;
-};
-
-#define CNDEVPATHMAX	32
-#define CNDEVTAB_SIZE	4
-static struct cn_device cn_devtab[CNDEVTAB_SIZE];
-static STAILQ_HEAD(, cn_device) cn_devlist =
-    STAILQ_HEAD_INITIALIZER(cn_devlist);
-
-#define CND_INVALID(cnd, td) 						\
-	(cnd == NULL || cnd->cnd_vp == NULL ||				\
-	    (cnd->cnd_vp->v_type == VBAD && !cn_devopen(cnd, td, 1)))
-
-static dev_t	cn_udev_t;
-SYSCTL_OPAQUE(_machdep, OID_AUTO, consdev, CTLFLAG_RD,
-	&cn_udev_t, sizeof cn_udev_t, "T,struct cdev *", "");
-
-int	cons_avail_mask = 0;	/* Bit mask. Each registered low level console
-				 * which is currently unavailable for inpit
-				 * (i.e., if it is in graphics mode) will have
-				 * this bit cleared.
-				 */
-static int cn_mute;
-static int openflag;			/* how /dev/console was opened */
-static int cn_is_open;
-static char *consbuf;			/* buffer used by `consmsgbuf' */
-static struct callout conscallout;	/* callout for outputting to constty */
-struct msgbuf consmsgbuf;		/* message buffer for console tty */
-static u_char console_pausing;		/* pause after each line during probe */
-static char *console_pausestr=
-"<pause; press any key to proceed to next line or '.' to end pause mode>";
-struct tty *constty;			/* pointer to console "window" tty */
-static struct mtx cnputs_mtx;		/* Mutex for cnputs(). */
-static int use_cnputs_mtx = 0;		/* != 0 if cnputs_mtx locking reqd. */
-
-static void constty_timeout(void *arg);
-
-static struct consdev cons_consdev;
-DATA_SET(cons_set, cons_consdev);
-SET_DECLARE(cons_set, struct consdev);
-
-void
-cninit(void)
-{
-	struct consdev *best_cn, *cn, **list;
-
-	/*
-	 * Check if we should mute the console (for security reasons perhaps)
-	 * It can be changes dynamically using sysctl kern.consmute
-	 * once we are up and going.
-	 * 
-	 */
-        cn_mute = ((boothowto & (RB_MUTE
-			|RB_SINGLE
-			|RB_VERBOSE
-			|RB_ASKNAME)) == RB_MUTE);
-
-	/*
-	 * Find the first console with the highest priority.
-	 */
-	best_cn = NULL;
-	SET_FOREACH(list, cons_set) {
-		cn = *list;
-		cnremove(cn);
-		if (cn->cn_probe == NULL)
-			continue;
-		cn->cn_probe(cn);
-		if (cn->cn_pri == CN_DEAD)
-			continue;
-		if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
-			best_cn = cn;
-		if (boothowto & RB_MULTIPLE) {
-			/*
-			 * Initialize console, and attach to it.
-			 */
-			cn->cn_init(cn);
-			cnadd(cn);
-		}
-	}
-	if (best_cn == NULL)
-		return;
-	if ((boothowto & RB_MULTIPLE) == 0) {
-		best_cn->cn_init(best_cn);
-		cnadd(best_cn);
-	}
-	if (boothowto & RB_PAUSE)
-		console_pausing = 1;
-	/*
-	 * Make the best console the preferred console.
-	 */
-	cnselect(best_cn);
-}
-
-void
-cninit_finish()
-{
-	console_pausing = 0;
-} 
-
-/* add a new physical console to back the virtual console */
-int
-cnadd(struct consdev *cn)
-{
-	struct cn_device *cnd;
-	int i;
-
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
-		if (cnd->cnd_cn == cn)
-			return (0);
-	for (i = 0; i < CNDEVTAB_SIZE; i++) {
-		cnd = &cn_devtab[i];
-		if (cnd->cnd_cn == NULL)
-			break;
-	}
-	if (cnd->cnd_cn != NULL)
-		return (ENOMEM);
-	cnd->cnd_cn = cn;
-	if (cn->cn_name[0] == '\0') {
-		/* XXX: it is unclear if/where this print might output */
-		printf("WARNING: console at %p has no name\n", cn);
-	}
-	STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
-
-	/* Add device to the active mask. */
-	cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
-
-	return (0);
-}
-
-void
-cnremove(struct consdev *cn)
-{
-	struct cn_device *cnd;
-	int i;
-
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
-		if (cnd->cnd_cn != cn)
-			continue;
-		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
-		if (cnd->cnd_vp != NULL)
-			vn_close(cnd->cnd_vp, openflag, NOCRED, NULL);
-		cnd->cnd_vp = NULL;
-		cnd->cnd_cn = NULL;
-
-		/* Remove this device from available mask. */
-		for (i = 0; i < CNDEVTAB_SIZE; i++) 
-			if (cnd == &cn_devtab[i]) {
-				cons_avail_mask &= ~(1 << i);
-				break;
-			}
-#if 0
-		/*
-		 * XXX
-		 * syscons gets really confused if console resources are
-		 * freed after the system has initialized.
-		 */
-		if (cn->cn_term != NULL)
-			cn->cn_term(cn);
-#endif
-		return;
-	}
-}
-
-void
-cnselect(struct consdev *cn)
-{
-	struct cn_device *cnd;
-
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
-		if (cnd->cnd_cn != cn)
-			continue;
-		if (cnd == STAILQ_FIRST(&cn_devlist))
-			return;
-		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
-		STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
-		return;
-	}
-}
-
-void
-cnavailable(struct consdev *cn, int available)
-{
-	int i;
-
-	for (i = 0; i < CNDEVTAB_SIZE; i++) {
-		if (cn_devtab[i].cnd_cn == cn)
-			break;
-	}
-	if (available) {
-		if (i < CNDEVTAB_SIZE)
-			cons_avail_mask |= (1 << i); 
-		cn->cn_flags &= ~CN_FLAG_NOAVAIL;
-	} else {
-		if (i < CNDEVTAB_SIZE)
-			cons_avail_mask &= ~(1 << i);
-		cn->cn_flags |= CN_FLAG_NOAVAIL;
-	}
-}
-
-int
-cnunavailable(void)
-{
-
-	return (cons_avail_mask == 0);
-}
-
-/*
- * sysctl_kern_console() provides output parseable in conscontrol(1).
- */
-static int
-sysctl_kern_console(SYSCTL_HANDLER_ARGS)
-{
-	struct cn_device *cnd;
-	struct consdev *cp, **list;
-	char *p;
-	int delete, error;
-	struct sbuf *sb;
-
-	sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND);
-	if (sb == NULL)
-		return (ENOMEM);
-	sbuf_clear(sb);
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
-		sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
-	sbuf_printf(sb, "/");
-	SET_FOREACH(list, cons_set) {
-		cp = *list;
-		if (cp->cn_name[0] != '\0')
-			sbuf_printf(sb, "%s,", cp->cn_name);
-	}
-	sbuf_finish(sb);
-	error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
-	if (error == 0 && req->newptr != NULL) {
-		p = sbuf_data(sb);
-		error = ENXIO;
-		delete = 0;
-		if (*p == '-') {
-			delete = 1;
-			p++;
-		}
-		SET_FOREACH(list, cons_set) {
-			cp = *list;
-			if (strcmp(p, cp->cn_name) != 0)
-				continue;
-			if (delete) {
-				cnremove(cp);
-				error = 0;
-			} else {
-				error = cnadd(cp);
-				if (error == 0)
-					cnselect(cp);
-			}
-			break;
-		}
-	}
-	sbuf_delete(sb);
-	return (error);
-}
-
-SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
-	0, 0, sysctl_kern_console, "A", "Console device control");
-
-/*
- * User has changed the state of the console muting.
- * This may require us to open or close the device in question.
- */
-static int
-sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
-{
-	int error;
-	int ocn_mute;
-
-	ocn_mute = cn_mute;
-	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
-	if (error != 0 || req->newptr == NULL)
-		return (error);
-	if (ocn_mute && !cn_mute && cn_is_open)
-		error = cnopen(NULL, openflag, 0, curthread);
-	else if (!ocn_mute && cn_mute && cn_is_open) {
-		error = cnclose(NULL, openflag, 0, curthread);
-		cn_is_open = 1;		/* XXX hack */
-	}
-	return (error);
-}
-
-SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
-	0, sizeof(cn_mute), sysctl_kern_consmute, "I", "");
-
-static int
-cn_devopen(struct cn_device *cnd, struct thread *td, int forceopen)
-{
-	char path[CNDEVPATHMAX];
-	struct nameidata nd;
-	struct vnode *vp;
-	struct cdev *dev;
-	struct cdevsw *csw;
-	int error;
-
-	if ((vp = cnd->cnd_vp) != NULL) {
-		if (!forceopen && vp->v_type != VBAD) {
-			dev = vp->v_rdev;
-			csw = dev_refthread(dev);
-			if (csw == NULL)
-				return (ENXIO);
-			error = (*csw->d_open)(dev, openflag, 0, td);
-			dev_relthread(dev);
-			return (error);
-		}
-		cnd->cnd_vp = NULL;
-		vn_close(vp, openflag, td->td_ucred, td);
-	}
-	snprintf(path, sizeof(path), "/dev/%s", cnd->cnd_cn->cn_name);
-	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path, td);
-	error = vn_open(&nd, &openflag, 0, NULL);
-	if (error == 0) {
-		NDFREE(&nd, NDF_ONLY_PNBUF);
-		VOP_UNLOCK(nd.ni_vp, 0);
-		if (nd.ni_vp->v_type == VCHR)
-			cnd->cnd_vp = nd.ni_vp;
-		else
-			vn_close(nd.ni_vp, openflag, td->td_ucred, td);
-	}
-	return (cnd->cnd_vp != NULL);
-}
-
-static int
-cnopen(struct cdev *dev, int flag, int mode, struct thread *td)
-{
-	struct cn_device *cnd;
-
-	openflag = flag | FWRITE;	/* XXX */
-	cn_is_open = 1;			/* console is logically open */
-	if (cn_mute)
-		return (0);
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
-		cn_devopen(cnd, td, 0);
-	return (0);
-}
-
-static int
-cnclose(struct cdev *dev, int flag, int mode, struct thread *td)
-{
-	struct cn_device *cnd;
-	struct vnode *vp;
-
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
-		if ((vp = cnd->cnd_vp) == NULL)
-			continue; 
-		cnd->cnd_vp = NULL;
-		vn_close(vp, openflag, td->td_ucred, td);
-	}
-	cn_is_open = 0;
-	return (0);
-}
-
-static int
-cnread(struct cdev *dev, struct uio *uio, int flag)
-{
-	struct cn_device *cnd;
-	struct cdevsw *csw;
-	int error;
-
-	cnd = STAILQ_FIRST(&cn_devlist);
-	if (cn_mute || CND_INVALID(cnd, curthread))
-		return (0);
-	dev = cnd->cnd_vp->v_rdev;
-	csw = dev_refthread(dev);
-	if (csw == NULL)
-		return (ENXIO);
-	error = (csw->d_read)(dev, uio, flag);
-	dev_relthread(dev);
-	return (error);
-}
-
-static int
-cnwrite(struct cdev *dev, struct uio *uio, int flag)
-{
-	struct cn_device *cnd;
-	struct cdevsw *csw;
-	int error;
-
-	cnd = STAILQ_FIRST(&cn_devlist);
-	if (cn_mute || CND_INVALID(cnd, curthread))
-		goto done;
-	if (constty)
-		dev = constty->t_dev;
-	else
-		dev = cnd->cnd_vp->v_rdev;
-	if (dev != NULL) {
-		log_console(uio);
-		csw = dev_refthread(dev);
-		if (csw == NULL)
-			return (ENXIO);
-		error = (csw->d_write)(dev, uio, flag);
-		dev_relthread(dev);
-		return (error);
-	}
-done:
-	uio->uio_resid = 0; /* dump the data */
-	return (0);
-}
-
-static int
-cnioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
-{
-	struct cn_device *cnd;
-	struct cdevsw *csw;
-	int error;
-
-	cnd = STAILQ_FIRST(&cn_devlist);
-	if (cn_mute || CND_INVALID(cnd, td))
-		return (0);
-	/*
-	 * Superuser can always use this to wrest control of console
-	 * output from the "virtual" console.
-	 */
-	if (cmd == TIOCCONS && constty) {
-		error = priv_check(td, PRIV_TTY_CONSOLE);
-		if (error)
-			return (error);
-		constty = NULL;
-		return (0);
-	}
-	dev = cnd->cnd_vp->v_rdev;
-	if (dev == NULL)
-		return (0);	/* XXX : ENOTTY ? */
-	csw = dev_refthread(dev);
-	if (csw == NULL)
-		return (ENXIO);
-	error = (csw->d_ioctl)(dev, cmd, data, flag, td);
-	dev_relthread(dev);
-	return (error);
-}
-
-/*
- * XXX
- * poll/kqfilter do not appear to be correct
- */
-static int
-cnpoll(struct cdev *dev, int events, struct thread *td)
-{
-	struct cn_device *cnd;
-	struct cdevsw *csw;
-	int error;
-
-	cnd = STAILQ_FIRST(&cn_devlist);
-	if (cn_mute || CND_INVALID(cnd, td))
-		return (0);
-	dev = cnd->cnd_vp->v_rdev;
-	if (dev == NULL)
-		return (0);
-	csw = dev_refthread(dev);
-	if (csw == NULL)
-		return (ENXIO);
-	error = (csw->d_poll)(dev, events, td);
-	dev_relthread(dev);
-	return (error);
-}
-
-static int
-cnkqfilter(struct cdev *dev, struct knote *kn)
-{
-	struct cn_device *cnd;
-	struct cdevsw *csw;
-	int error;
-
-	cnd = STAILQ_FIRST(&cn_devlist);
-	if (cn_mute || CND_INVALID(cnd, curthread))
-		return (EINVAL);
-	dev = cnd->cnd_vp->v_rdev;
-	if (dev == NULL)
-		return (ENXIO);
-	csw = dev_refthread(dev);
-	if (csw == NULL)
-		return (ENXIO);
-	error = (csw->d_kqfilter)(dev, kn);
-	dev_relthread(dev);
-	return (error);
-}
-
-/*
- * Low level console routines.
- */
-int
-cngetc(void)
-{
-	int c;
-
-	if (cn_mute)
-		return (-1);
-	while ((c = cncheckc()) == -1)
-		;
-	if (c == '\r')
-		c = '\n';		/* console input is always ICRNL */
-	return (c);
-}
-
-int
-cncheckc(void)
-{
-	struct cn_device *cnd;
-	struct consdev *cn;
-	int c;
-
-	if (cn_mute)
-		return (-1);
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
-		cn = cnd->cnd_cn;
-		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
-			if (cn->cn_checkc != NULL)
-				c = cn->cn_checkc(cn);
-			else
-				c = cn->cn_getc(cn);
-			if (c != -1) {
-				return (c);
-			}
-		}
-	}
-	return (-1);
-}
-
-void
-cnputc(int c)
-{
-	struct cn_device *cnd;
-	struct consdev *cn;
-	char *cp;
-
-	if (cn_mute || c == '\0')
-		return;
-	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
-		cn = cnd->cnd_cn;
-		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
-			if (c == '\n')
-				cn->cn_putc(cn, '\r');
-			cn->cn_putc(cn, c);
-		}
-	}
-	if (console_pausing && c == '\n' && !kdb_active) {
-		for (cp = console_pausestr; *cp != '\0'; cp++)
-			cnputc(*cp);
-		if (cngetc() == '.')
-			console_pausing = 0;
-		cnputc('\r');
-		for (cp = console_pausestr; *cp != '\0'; cp++)
-			cnputc(' ');
-		cnputc('\r');
-	}
-}
-
-void
-cnputs(char *p)
-{
-	int c;
-	int unlock_reqd = 0;
-
-	if (use_cnputs_mtx) {
-		mtx_lock_spin(&cnputs_mtx);
-		unlock_reqd = 1;
-	}
-
-	while ((c = *p++) != '\0')
-		cnputc(c);
-
-	if (unlock_reqd)
-		mtx_unlock_spin(&cnputs_mtx);
-}
-
-static int consmsgbuf_size = 8192;
-SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
-    "");
-
-/*
- * Redirect console output to a tty.
- */
-void
-constty_set(struct tty *tp)
-{
-	int size;
-
-	KASSERT(tp != NULL, ("constty_set: NULL tp"));
-	if (consbuf == NULL) {
-		size = consmsgbuf_size;
-		consbuf = malloc(size, M_TTYCONS, M_WAITOK);
-		msgbuf_init(&consmsgbuf, consbuf, size);
-		callout_init(&conscallout, 0);
-	}
-	constty = tp;
-	constty_timeout(NULL);
-}
-
-/*
- * Disable console redirection to a tty.
- */
-void
-constty_clear(void)
-{
-	int c;
-
-	constty = NULL;
-	if (consbuf == NULL)
-		return;
-	callout_stop(&conscallout);
-	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
-		cnputc(c);
-	free(consbuf, M_TTYCONS);
-	consbuf = NULL;
-}
-
-/* Times per second to check for pending console tty messages. */
-static int constty_wakeups_per_second = 5;
-SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
-    &constty_wakeups_per_second, 0, "");
-
-static void
-constty_timeout(void *arg)
-{
-	int c;
-
-	if (constty != NULL) {
-		tty_lock(constty);
-		while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
-			if (tty_putchar(constty, c) < 0) {
-				tty_unlock(constty);
-				constty = NULL;
-				break;
-			}
-		}
-
-		if (constty != NULL)
-			tty_unlock(constty);
-	}
-	if (constty != NULL) {
-		callout_reset(&conscallout, hz / constty_wakeups_per_second,
-		    constty_timeout, NULL);
-	} else {
-		/* Deallocate the constty buffer memory. */
-		constty_clear();
-	}
-}
-
-static void
-cn_drvinit(void *unused)
-{
-
-	make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "console");
-
-	mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
-	use_cnputs_mtx = 1;
-}
-
-SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
-
-/*
- * Sysbeep(), if we have hardware for it
- */
-
-#ifdef HAS_TIMER_SPKR
-
-static int beeping;
-
-static void
-sysbeepstop(void *chan)
-{
-
-	timer_spkr_release();
-	beeping = 0;
-}
-
-int
-sysbeep(int pitch, int period)
-{
-
-	if (timer_spkr_acquire()) {
-		if (!beeping) {
-			/* Something else owns it. */
-			return (EBUSY);
-		}
-	}
-	timer_spkr_setfreq(pitch);
-	if (!beeping) {
-		beeping = period;
-		timeout(sysbeepstop, (void *)NULL, period);
-	}
-	return (0);
-}
-
-#else
-
-/*
- * No hardware, no sound
- */
-
-int
-sysbeep(int pitch __unused, int period __unused)
-{
-
-	return (ENODEV);
-}
-
-#endif
-