File:  [DragonFly] / src / sys / kern / tty_cons.c
Revision 1.13: download - view: text, annotated - select for diffs
Wed May 19 22:52:58 2004 UTC (9 years, 11 months ago) by dillon
Branches: MAIN
CVS tags: HEAD, DragonFly_1_0_REL, DragonFly_1_0_RC1, DragonFly_1_0A_REL
Device layer rollup commit.

* cdevsw_add() is now required.  cdevsw_add() and cdevsw_remove() may specify
  a mask/match indicating the range of supported minor numbers.  Multiple
  cdevsw_add()'s using the same major number, but distinctly different
  ranges, may be issued.  All devices that failed to call cdevsw_add() before
  now do.

* cdevsw_remove() now automatically marks all devices within its supported
  range as being destroyed.

* vnode->v_rdev is no longer resolved when the vnode is created.  Instead,
  only v_udev (a newly added field) is resolved.  v_rdev is resolved when
  the vnode is opened and cleared on the last close.

* A great deal of code was making rather dubious assumptions with regards
  to the validity of devices associated with vnodes, primarily due to
  the persistence of a device structure due to being indexed by (major, minor)
  instead of by (cdevsw, major, minor).  In particular, if you run a program
  which connects to a USB device and then you pull the USB device and plug
  it back in, the vnode subsystem will continue to believe that the device
  is open when, in fact, it isn't (because it was destroyed and recreated).

  In particular, note that all the VFS mount procedures now check devices
  via v_udev instead of v_rdev prior to calling VOP_OPEN(), since v_rdev
  is NULL prior to the first open.

* The disk layer's device interaction has been rewritten.  The disk layer
  (i.e. the slice and disklabel management layer) no longer overloads
  its data onto the device structure representing the underlying physical
  disk.  Instead, the disk layer uses the new cdevsw_add() functionality
  to register its own cdevsw using the underlying device's major number,
  and simply does NOT register the underlying device's cdevsw.  No
  confusion is created because the device hash is now based on
  (cdevsw,major,minor) rather then (major,minor).

  NOTE: This also means that underlying raw disk devices may use the entire
  device minor number instead of having to reserve the bits used by the disk
  layer, and also means that can we (theoretically) stack a fully
  disklabel-supported 'disk' on top of any block device.

* The new reference counting scheme prevents this by associating a device
  with a cdevsw and disconnecting the device from its cdevsw when the cdevsw
  is removed.  Additionally, all udev2dev() lookups run through the cdevsw
  mask/match and only successfully find devices still associated with an
  active cdevsw.

* Major work on MFS:  MFS no longer shortcuts vnode and device creation.  It
  now creates a real vnode and a real device and implements real open and
  close VOPs.  Additionally, due to the disk layer changes, MFS is no longer
  limited to 255 mounts.  The new limit is 16 million.  Since MFS creates a
  real device node, mount_mfs will now create a real /dev/mfs<PID> device
  that can be read from userland (e.g. so you can dump an MFS filesystem).

* BUF AND DEVICE STRATEGY changes.  The struct buf contains a b_dev field.
  In order to properly handle stacked devices we now require that the b_dev
  field be initialized before the device strategy routine is called.  This
  required some additional work in various VFS implementations.  To enforce
  this requirement, biodone() now sets b_dev to NODEV.  The new disk layer
  will adjust b_dev before forwarding a request to the actual physical
  device.

* A bug in the ISO CD boot sequence which resulted in a panic has been fixed.

Testing by: lots of people, but David Rhodus found the most aggregious bugs.

/*
 * 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
 * $FreeBSD: src/sys/kern/tty_cons.c,v 1.81.2.4 2001/12/17 18:44:41 guido Exp $
 * $DragonFly: src/sys/kern/tty_cons.c,v 1.13 2004/05/19 22:52:58 dillon Exp $
 */

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <sys/tty.h>
#include <sys/uio.h>
#include <sys/msgport.h>
#include <sys/msgport2.h>
#include <sys/device.h>

#include <ddb/ddb.h>

#include <machine/cpu.h>

static int cnopen(struct cdevmsg_open *msg);
static int cnclose(struct cdevmsg_close *msg);
static int cnread(struct cdevmsg_read *msg);
static int cnwrite(struct cdevmsg_write *msg);
static int cnioctl(struct cdevmsg_ioctl *msg);
static int cnpoll(struct cdevmsg_poll *msg);
static int cnkqfilter(struct cdevmsg_kqfilter *msg);

static int console_putport(lwkt_port_t port, lwkt_msg_t lmsg);
static int console_interceptport(lwkt_port_t port, lwkt_msg_t lmsg);

static struct lwkt_port	cn_port;	/* console device port */
static struct lwkt_port	cn_iport;	/* intercept port */

#define	CDEV_MAJOR	0
static struct cdevsw cn_cdevsw = {
	/* name */	"console",
	/* maj */	CDEV_MAJOR,
	/* flags */	D_TTY | D_KQFILTER,
	/* port */	&cn_port,
	/* clone */	NULL
};

static dev_t	cn_dev_t;
static udev_t	cn_udev_t;
SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
	&cn_udev_t, sizeof cn_udev_t, "T,dev_t", "");

static int cn_mute;

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 int openmode, openflag;		/* how /dev/console was openned */
static dev_t cn_devfsdev;		/* represents the device private info */
static u_char cn_phys_is_open;		/* nonzero if physical device is open */
       struct consdev *cn_tab;		/* physical console device info */
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>";

static lwkt_port_t	cn_fwd_port;

CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
SET_DECLARE(cons_set, struct consdev);

void
cninit()
{
	struct consdev *best_cp, *cp, **list;

	/*
	 * Our port intercept
	 */
	lwkt_initport(&cn_port, NULL);
	cn_port.mp_putport = console_putport;
	lwkt_initport(&cn_iport, NULL);
	cn_iport.mp_putport = console_interceptport;

	/*
	 * Find the first console with the highest priority.
	 */
	best_cp = NULL;
	SET_FOREACH(list, cons_set) {
		cp = *list;
		if (cp->cn_probe == NULL)
			continue;
		(*cp->cn_probe)(cp);
		if (cp->cn_pri > CN_DEAD &&
		    (best_cp == NULL || cp->cn_pri > best_cp->cn_pri))
			best_cp = cp;
	}

	/*
	 * 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_CONFIG)) == RB_MUTE);
	
	/*
	 * If no console, give up.
	 */
	if (best_cp == NULL) {
		if (cn_tab != NULL && cn_tab->cn_term != NULL)
			(*cn_tab->cn_term)(cn_tab);
		cn_tab = best_cp;
		return;
	}

	/*
	 * Initialize console, then attach to it.  This ordering allows
	 * debugging using the previous console, if any.
	 */
	(*best_cp->cn_init)(best_cp);
	if (cn_tab != NULL && cn_tab != best_cp) {
		/* Turn off the previous console.  */
		if (cn_tab->cn_term != NULL)
			(*cn_tab->cn_term)(cn_tab);
	}
	if (boothowto & RB_PAUSE)
		console_pausing = 1;
	cn_tab = best_cp;
}

/*
 * Hook the open and close functions on the selected device.
 */
void
cninit_finish()
{
	if ((cn_tab == NULL) || cn_mute)
		return;

	/*
	 * Hook the open and close functions.  XXX bad hack.
	 */
	if (dev_is_good(cn_tab->cn_dev))
		cn_fwd_port = cdevsw_dev_override(cn_tab->cn_dev, &cn_iport);
	cn_dev_t = cn_tab->cn_dev;
	cn_udev_t = dev2udev(cn_dev_t);
	console_pausing = 0;
}

static void
cnuninit(void)
{
	if (cn_tab == NULL)
		return;

	/*
	 * Unhook the open and close functions.  XXX bad hack
	 */
	if (cn_fwd_port)
		cdevsw_dev_override(cn_tab->cn_dev, cn_fwd_port);
	cn_fwd_port = NULL;
	cn_dev_t = NODEV;
	cn_udev_t = NOUDEV;
}

/*
 * 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) && (cn_tab != NULL) && (req->newptr != NULL)) {
		if(ocn_mute && !cn_mute) {
			/*
			 * going from muted to unmuted.. open the physical dev 
			 * if the console has been openned
			 */
			cninit_finish();
			if (cn_is_open) {
				/* XXX curproc is not what we want really */
				error = dev_dopen(cn_dev_t, openflag,
						openmode, curthread);
			}
			/* if it failed, back it out */
			if ( error != 0) cnuninit();
		} else if (!ocn_mute && cn_mute) {
			/*
			 * going from unmuted to muted.. close the physical dev 
			 * if it's only open via /dev/console
			 */
			if (cn_is_open) {
				error = dev_dclose(cn_dev_t, openflag,
						openmode, curthread);
			}
			if (error == 0)
				cnuninit();
		}
		if (error != 0) {
			/* 
	 		 * back out the change if there was an error
			 */
			cn_mute = ocn_mute;
		}
	}
	return (error);
}

SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
	0, sizeof cn_mute, sysctl_kern_consmute, "I", "");

/*
 * We intercept the OPEN and CLOSE calls on the original device, and
 * forward the rest through.
 */
static int
console_interceptport(lwkt_port_t port, lwkt_msg_t lmsg)
{
	cdevallmsg_t msg = (cdevallmsg_t)lmsg;
	int error;

	switch(msg->am_lmsg.ms_cmd.cm_op) {
	case CDEV_CMD_OPEN:
		error = cnopen(&msg->am_open);
		break;
	case CDEV_CMD_CLOSE:
		error = cnclose(&msg->am_close);
		break;
	default:
		error = lwkt_forwardmsg(cn_fwd_port, &msg->am_lmsg);
		break;
	}
	return(error);
}

/*
 * This is the port handler for /dev/console.  These functions will basically
 * past the request through to the actual physical device representing the
 * console. 
 *
 * Note, however, that cnopen() and cnclose() are also called from the mute
 * code and the intercept code.
 */
static int
console_putport(lwkt_port_t port, lwkt_msg_t lmsg)
{
	cdevallmsg_t msg = (cdevallmsg_t)lmsg;
	int error;

	switch(msg->am_lmsg.ms_cmd.cm_op) {
	case CDEV_CMD_OPEN:
		error = cnopen(&msg->am_open);
		break;
	case CDEV_CMD_CLOSE:
		error = cnclose(&msg->am_close);
		break;
	case CDEV_CMD_STRATEGY:
		nostrategy(msg->am_strategy.bp);
		error = 0;
		break;
	case CDEV_CMD_IOCTL:
		error = cnioctl(&msg->am_ioctl);
		break;
	case CDEV_CMD_DUMP:
		error = nodump(msg->am_dump.msg.dev, 0, 0, 0);
		break;
	case CDEV_CMD_PSIZE:
		error = nopsize(msg->am_psize.msg.dev);
		break;
	case CDEV_CMD_READ:
		error = cnread(&msg->am_read);
		break;
	case CDEV_CMD_WRITE:
		error = cnwrite(&msg->am_write);
		break;
	case CDEV_CMD_POLL:
		error = cnpoll(&msg->am_poll);
		break;
	case CDEV_CMD_KQFILTER:
		error = cnkqfilter(&msg->am_kqfilter);
		break;
	case CDEV_CMD_MMAP:
		error = nommap(msg->am_mmap.msg.dev,
				msg->am_mmap.offset,
				msg->am_mmap.nprot);
		break;
	default:
		error = ENODEV;
		break;
	}
	return(error);
}

/*
 * cnopen() is called as a port intercept function (dev will be that of the
 * actual physical device representing our console), and also called from
 * the muting code and from the /dev/console switch (dev will have the
 * console's cdevsw).
 */
static int
cnopen(struct cdevmsg_open *msg)
{
	dev_t dev = msg->msg.dev;
	int flag = msg->oflags;
	int mode = msg->devtype;
	dev_t cndev, physdev;
	int retval = 0;

	if (cn_tab == NULL || cn_fwd_port == NULL)
		return (0);
	cndev = cn_tab->cn_dev;
	physdev = (major(dev) == major(cndev) ? dev : cndev);

	/*
	 * If mute is active, then non console opens don't get here
	 * so we don't need to check for that. They bypass this and go
	 * straight to the device.
	 *
	 * XXX at the moment we assume that the port forwarding function
	 * is synchronous for open.
	 */
	if (!cn_mute) {
		msg->msg.dev = physdev;
		retval = lwkt_forwardmsg(cn_fwd_port, &msg->msg.msg);
	}
	if (retval == 0) {
		/* 
		 * check if we openned it via /dev/console or 
		 * via the physical entry (e.g. /dev/sio0).
		 */
		if (dev == cndev)
			cn_phys_is_open = 1;
		else if (physdev == cndev) {
			openmode = mode;
			openflag = flag;
			cn_is_open = 1;
		}
		dev->si_tty = physdev->si_tty;
	}
	return (retval);
}

/*
 * cnclose() is called as a port intercept function (dev will be that of the
 * actual physical device representing our console), and also called from
 * the muting code and from the /dev/console switch (dev will have the
 * console's cdevsw).
 */
static int
cnclose(struct cdevmsg_close *msg)
{
	dev_t dev = msg->msg.dev;
	dev_t cndev;
	struct tty *cn_tp;

	if (cn_tab == NULL || cn_fwd_port == NULL)
		return (0);
	cndev = cn_tab->cn_dev;
	cn_tp = cndev->si_tty;
	/*
	 * act appropriatly depending on whether it's /dev/console
	 * or the pysical device (e.g. /dev/sio) that's being closed.
	 * in either case, don't actually close the device unless
	 * both are closed.
	 */
	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;
	}
	if (cn_fwd_port) {
		msg->msg.dev = dev;
		return(lwkt_forwardmsg(cn_fwd_port, &msg->msg.msg));
	}
	return (0);
}

/*
 * The following functions are dispatched solely from the /dev/console
 * port switch.  Their job is primarily to forward the request through.
 * If the console is not attached to anything then write()'s are sunk
 * to null and reads return 0 (mostly).
 */
static int
cnread(struct cdevmsg_read *msg)
{
	if (cn_tab == NULL || cn_fwd_port == NULL)
		return (0);
	msg->msg.dev = cn_tab->cn_dev;
	return(lwkt_forwardmsg(cn_fwd_port, &msg->msg.msg));
}

static int
cnwrite(struct cdevmsg_write *msg)
{
	struct uio *uio = msg->uio;
	dev_t dev;

	if (cn_tab == NULL || cn_fwd_port == NULL) {
		uio->uio_resid = 0; /* dump the data */
		return (0);
	}
	if (constty)
		dev = constty->t_dev;
	else
		dev = cn_tab->cn_dev;
	log_console(uio);
	msg->msg.dev = dev;
	return(lwkt_forwardmsg(cn_fwd_port, &msg->msg.msg));
}

static int
cnioctl(struct cdevmsg_ioctl *msg)
{
	u_long cmd = msg->cmd;
	int error;

	if (cn_tab == NULL || cn_fwd_port == NULL)
		return (0);
	KKASSERT(msg->td->td_proc != NULL);
	/*
	 * Superuser can always use this to wrest control of console
	 * output from the "virtual" console.
	 */
	if (cmd == TIOCCONS && constty) {
		error = suser(msg->td);
		if (error)
			return (error);
		constty = NULL;
		return (0);
	}
	msg->msg.dev = cn_tab->cn_dev;
	return(lwkt_forwardmsg(cn_fwd_port, &msg->msg.msg));
}

static int
cnpoll(struct cdevmsg_poll *msg)
{
	if ((cn_tab == NULL) || cn_mute || cn_fwd_port == NULL)
		return (1);
	msg->msg.dev = cn_tab->cn_dev;
	return(lwkt_forwardmsg(cn_fwd_port, &msg->msg.msg));
}

static int
cnkqfilter(struct cdevmsg_kqfilter *msg)
{
	if ((cn_tab == NULL) || cn_mute || cn_fwd_port == NULL)
		return (1);
	msg->msg.dev = cn_tab->cn_dev;
	return(lwkt_forwardmsg(cn_fwd_port, &msg->msg.msg));
}

/*
 * These synchronous functions are primarily used the kernel needs to 
 * access the keyboard (e.g. when running the debugger), or output data
 * directly to the console.
 */
int
cngetc(void)
{
	int c;
	if ((cn_tab == NULL) || cn_mute)
		return (-1);
	c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
	if (c == '\r') c = '\n'; /* console input is always ICRNL */
	return (c);
}

int
cncheckc(void)
{
	if ((cn_tab == NULL) || cn_mute)
		return (-1);
	return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
}

void
cnputc(int c)
{
	char *cp;

	if ((cn_tab == NULL) || cn_mute)
		return;
	if (c) {
		if (c == '\n')
			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
		(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
#ifdef DDB
		if (console_pausing && !db_active && (c == '\n')) {
#else
		if (console_pausing && (c == '\n')) {
#endif
			for(cp=console_pausestr; *cp != '\0'; cp++)
			    (*cn_tab->cn_putc)(cn_tab->cn_dev, *cp);
			if (cngetc() == '.')
				console_pausing = 0;
			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
			for(cp=console_pausestr; *cp != '\0'; cp++)
			    (*cn_tab->cn_putc)(cn_tab->cn_dev, ' ');
			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
		}
	}
}

void
cndbctl(int on)
{
	static int refcount;

	if (cn_tab == NULL)
		return;
	if (!on)
		refcount--;
	if (refcount == 0 && cn_tab->cn_dbctl != NULL)
		(*cn_tab->cn_dbctl)(cn_tab->cn_dev, on);
	if (on)
		refcount++;
}

static void
cn_drvinit(void *unused)
{
	cdevsw_add(&cn_cdevsw, 0, 0);
	cn_devfsdev = make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL,
				0600, "console");
}

SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)