kern_subr.c

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/*	$NetBSD: kern_subr.c,v 1.74 2000/12/10 14:14:15 fvdl Exp $	*/

/*-
 * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center, and by Luke Mewburn.
 *
 * 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 NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Copyright (c) 1982, 1986, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * 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, Lawrence Berkeley Laboratory.
 *
 * 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.
 *
 *	@(#)kern_subr.c	8.4 (Berkeley) 2/14/95
 */

#include "opt_md.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/device.h>
#include <sys/reboot.h>
#include <sys/conf.h>
#include <sys/disklabel.h>
#include <sys/queue.h>

#ifndef OSKIT
#include <dev/cons.h>

#include <net/if.h>

/* XXX these should eventually move to subr_autoconf.c */
static int findblkmajor __P((const char *));
const char *findblkname __P((int));
static struct device *finddevice __P((const char *));
static struct device *getdisk __P((char *, int, int, dev_t *, int));
static struct device *parsedisk __P((char *, int, int, dev_t *));

int
uiomove(buf, n, uio)
	void *buf;
	int n;
	struct uio *uio;
{
	struct iovec *iov;
	u_int cnt;
	int error = 0;
	char *cp = buf;
	struct proc *p = uio->uio_procp;

#ifdef DIAGNOSTIC
	if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
		panic("uiomove: mode");
	if (uio->uio_segflg == UIO_USERSPACE && p != curproc)
		panic("uiomove proc");
#endif
	while (n > 0 && uio->uio_resid) {
		iov = uio->uio_iov;
		cnt = iov->iov_len;
		if (cnt == 0) {
			uio->uio_iov++;
			uio->uio_iovcnt--;
			continue;
		}
		if (cnt > n)
			cnt = n;
		switch (uio->uio_segflg) {

		case UIO_USERSPACE:
			KDASSERT(p->p_cpu != NULL);
			KDASSERT(p->p_cpu == curcpu());
			if (p->p_cpu->ci_schedstate.spc_flags &
			    SPCF_SHOULDYIELD)
				preempt(NULL);
			if (uio->uio_rw == UIO_READ)
				error = copyout(cp, iov->iov_base, cnt);
			else
				error = copyin(iov->iov_base, cp, cnt);
			if (error)
				return (error);
			break;

		case UIO_SYSSPACE:
			if (uio->uio_rw == UIO_READ)
				error = kcopy(cp, iov->iov_base, cnt);
			else
				error = kcopy(iov->iov_base, cp, cnt);
			if (error)
				return (error);
			break;
		}
		iov->iov_base = (caddr_t)iov->iov_base + cnt;
		iov->iov_len -= cnt;
		uio->uio_resid -= cnt;
		uio->uio_offset += cnt;
		cp += cnt;
		n -= cnt;
	}
	return (error);
}

/*
 * Give next character to user as result of read.
 */
int
ureadc(c, uio)
	int c;
	struct uio *uio;
{
	struct iovec *iov;

	if (uio->uio_resid <= 0)
		panic("ureadc: non-positive resid");
again:
	if (uio->uio_iovcnt <= 0)
		panic("ureadc: non-positive iovcnt");
	iov = uio->uio_iov;
	if (iov->iov_len <= 0) {
		uio->uio_iovcnt--;
		uio->uio_iov++;
		goto again;
	}
	switch (uio->uio_segflg) {

	case UIO_USERSPACE:
		if (subyte(iov->iov_base, c) < 0)
			return (EFAULT);
		break;

	case UIO_SYSSPACE:
		*(char *)iov->iov_base = c;
		break;
	}
	iov->iov_base = (caddr_t)iov->iov_base + 1;
	iov->iov_len--;
	uio->uio_resid--;
	uio->uio_offset++;
	return (0);
}
#endif /*OSKIT*/

/*
 * General routine to allocate a hash table.
 * Allocate enough memory to hold at least `elements' list-head pointers.
 * Return a pointer to the allocated space and set *hashmask to a pattern
 * suitable for masking a value to use as an index into the returned array.
 */
void *
hashinit(elements, htype, mtype, mflags, hashmask)
	int elements;
	enum hashtype htype;
	int mtype, mflags;
	u_long *hashmask;
{
	long hashsize;
	LIST_HEAD(, generic) *hashtbl_list;
	TAILQ_HEAD(, generic) *hashtbl_tailq;
	int i, esize;
	void *p;

	if (elements <= 0)
		panic("hashinit: bad cnt");
	for (hashsize = 1; hashsize < elements; hashsize <<= 1)
		continue;

	switch (htype) {
	case HASH_LIST:
		esize = sizeof(*hashtbl_list);
		break;
	case HASH_TAILQ:
		esize = sizeof(*hashtbl_tailq);
		break;
#ifdef DIAGNOSTIC
	default:
		panic("hashinit: invalid table type");
#endif
	}

	if ((p = malloc((u_long)hashsize * esize, mtype, mflags)) == NULL)
		return (NULL);

	switch (htype) {
	case HASH_LIST:
		hashtbl_list = p;
		for (i = 0; i < hashsize; i++)
			LIST_INIT(&hashtbl_list[i]);
		break;
	case HASH_TAILQ:
		hashtbl_tailq = p;
		for (i = 0; i < hashsize; i++)
			TAILQ_INIT(&hashtbl_tailq[i]);
		break;
	}
	*hashmask = hashsize - 1;
	return (p);
}

/*
 * Free memory from hash table previosly allocated via hashinit().
 */
void
hashdone(hashtbl, mtype)
	void *hashtbl;
	int mtype;
{

	free(hashtbl, mtype);
}

#ifndef OSKIT
/*
 * "Shutdown hook" types, functions, and variables.
 */

struct shutdownhook_desc {
	LIST_ENTRY(shutdownhook_desc) sfd_list;
	void	(*sfd_fn) __P((void *));
	void	*sfd_arg;
};

LIST_HEAD(, shutdownhook_desc) shutdownhook_list;

void *
shutdownhook_establish(fn, arg)
	void (*fn) __P((void *));
	void *arg;
{
	struct shutdownhook_desc *ndp;

	ndp = (struct shutdownhook_desc *)
	    malloc(sizeof(*ndp), M_DEVBUF, M_NOWAIT);
	if (ndp == NULL)
		return (NULL);

	ndp->sfd_fn = fn;
	ndp->sfd_arg = arg;
	LIST_INSERT_HEAD(&shutdownhook_list, ndp, sfd_list);

	return (ndp);
}

void
shutdownhook_disestablish(vhook)
	void *vhook;
{
#ifdef DIAGNOSTIC
	struct shutdownhook_desc *dp;

	for (dp = shutdownhook_list.lh_first; dp != NULL;
	    dp = dp->sfd_list.le_next)
                if (dp == vhook)
			break;
	if (dp == NULL)
		panic("shutdownhook_disestablish: hook not established");
#endif

	LIST_REMOVE((struct shutdownhook_desc *)vhook, sfd_list);
	free(vhook, M_DEVBUF);
}

/*
 * Run shutdown hooks.  Should be invoked immediately before the
 * system is halted or rebooted, i.e. after file systems unmounted,
 * after crash dump done, etc.
 *
 * Each shutdown hook is removed from the list before it's run, so that
 * it won't be run again.
 */
void
doshutdownhooks()
{
	struct shutdownhook_desc *dp;

	while ((dp = shutdownhook_list.lh_first) != NULL) {
		LIST_REMOVE(dp, sfd_list);
		(*dp->sfd_fn)(dp->sfd_arg);
#if 0
		/*
		 * Don't bother freeing the hook structure,, since we may
		 * be rebooting because of a memory corruption problem,
		 * and this might only make things worse.  It doesn't
		 * matter, anyway, since the system is just about to
		 * reboot.
		 */
		free(dp, M_DEVBUF);
#endif
	}
}

/*
 * "Power hook" types, functions, and variables.
 * The list of power hooks is kept ordered with the last registered hook
 * first.
 * When running the hooks on power down the hooks are called in reverse
 * registration order, when powering up in registration order.
 */

struct powerhook_desc {
	CIRCLEQ_ENTRY(powerhook_desc) sfd_list;
	void	(*sfd_fn) __P((int, void *));
	void	*sfd_arg;
};

CIRCLEQ_HEAD(, powerhook_desc) powerhook_list =
	CIRCLEQ_HEAD_INITIALIZER(powerhook_list);

void *
powerhook_establish(fn, arg)
	void (*fn) __P((int, void *));
	void *arg;
{
	struct powerhook_desc *ndp;

	ndp = (struct powerhook_desc *)
	    malloc(sizeof(*ndp), M_DEVBUF, M_NOWAIT);
	if (ndp == NULL)
		return (NULL);

	ndp->sfd_fn = fn;
	ndp->sfd_arg = arg;
	CIRCLEQ_INSERT_HEAD(&powerhook_list, ndp, sfd_list);

	return (ndp);
}

void
powerhook_disestablish(vhook)
	void *vhook;
{
#ifdef DIAGNOSTIC
	struct powerhook_desc *dp;

	CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list)
                if (dp == vhook)
			goto found;
	panic("powerhook_disestablish: hook not established");
 found:
#endif

	CIRCLEQ_REMOVE(&powerhook_list, (struct powerhook_desc *)vhook,
	    sfd_list);
	free(vhook, M_DEVBUF);
}

/*
 * Run power hooks.
 */
void
dopowerhooks(why)
	int why;
{
	struct powerhook_desc *dp;

	if (why == PWR_RESUME || why == PWR_SOFTRESUME) {
		CIRCLEQ_FOREACH_REVERSE(dp, &powerhook_list, sfd_list) {
			(*dp->sfd_fn)(why, dp->sfd_arg);
		}
	} else {
		CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list) {
			(*dp->sfd_fn)(why, dp->sfd_arg);
		}
	}
}

/*
 * "Mountroot hook" types, functions, and variables.
 */

struct mountroothook_desc {
	LIST_ENTRY(mountroothook_desc) mrd_list;
	struct	device *mrd_device;
	void 	(*mrd_func) __P((struct device *));
};

LIST_HEAD(, mountroothook_desc) mountroothook_list;

void *
mountroothook_establish(func, dev)
	void (*func) __P((struct device *));
	struct device *dev;
{
	struct mountroothook_desc *mrd;

	mrd = (struct mountroothook_desc *)
	    malloc(sizeof(*mrd), M_DEVBUF, M_NOWAIT);
	if (mrd == NULL)
		return (NULL);

	mrd->mrd_device = dev;
	mrd->mrd_func = func;
	LIST_INSERT_HEAD(&mountroothook_list, mrd, mrd_list);

	return (mrd);
}

void
mountroothook_disestablish(vhook)
	void *vhook;
{
#ifdef DIAGNOSTIC
	struct mountroothook_desc *mrd;

	for (mrd = mountroothook_list.lh_first; mrd != NULL;
	    mrd = mrd->mrd_list.le_next)
                if (mrd == vhook)
			break;
	if (mrd == NULL)
		panic("mountroothook_disestablish: hook not established");
#endif

	LIST_REMOVE((struct mountroothook_desc *)vhook, mrd_list);
	free(vhook, M_DEVBUF);
}

void
mountroothook_destroy()
{
	struct mountroothook_desc *mrd;

	while ((mrd = mountroothook_list.lh_first) != NULL) {
		LIST_REMOVE(mrd, mrd_list);
		free(mrd, M_DEVBUF);
	}
}

void
domountroothook()
{
	struct mountroothook_desc *mrd;

	for (mrd = mountroothook_list.lh_first; mrd != NULL;
	    mrd = mrd->mrd_list.le_next) {
		if (mrd->mrd_device == root_device) {
			(*mrd->mrd_func)(root_device);
			return;
		}
	}
}

/*
 * Exec hook code.
 */

struct exechook_desc {
	LIST_ENTRY(exechook_desc) ehk_list;
	void	(*ehk_fn) __P((struct proc *, void *));
	void	*ehk_arg;
};

LIST_HEAD(, exechook_desc) exechook_list;

void *
exechook_establish(fn, arg)
	void (*fn) __P((struct proc *, void *));
	void *arg;
{
	struct exechook_desc *edp;

	edp = (struct exechook_desc *)
	    malloc(sizeof(*edp), M_DEVBUF, M_NOWAIT);
	if (edp == NULL)
		return (NULL);

	edp->ehk_fn = fn;
	edp->ehk_arg = arg;
	LIST_INSERT_HEAD(&exechook_list, edp, ehk_list);

	return (edp);
}

void
exechook_disestablish(vhook)
	void *vhook;
{
#ifdef DIAGNOSTIC
	struct exechook_desc *edp;

	for (edp = exechook_list.lh_first; edp != NULL;
	    edp = edp->ehk_list.le_next)
                if (edp == vhook)
			break;
	if (edp == NULL)
		panic("exechook_disestablish: hook not established");
#endif

	LIST_REMOVE((struct exechook_desc *)vhook, ehk_list);
	free(vhook, M_DEVBUF);
}

/*
 * Run exec hooks.
 */
void