xref: /src/sys/kern/kern_subr.c

/*	$NetBSD: kern_subr.c,v 1.203 2009/11/05 18:07:19 dyoung Exp $	*/

/*-
 * Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008 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.
 *
 * 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. 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_subr.c,v 1.203 2009/11/05 18:07:19 dyoung Exp $");

#include "opt_ddb.h"
#include "opt_md.h"
#include "opt_syscall_debug.h"
#include "opt_ktrace.h"
#include "opt_ptrace.h"
#include "opt_powerhook.h"
#include "opt_tftproot.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/disk.h>
#include <sys/disklabel.h>
#include <sys/queue.h>
#include <sys/ktrace.h>
#include <sys/ptrace.h>
#include <sys/fcntl.h>
#include <sys/kauth.h>
#include <sys/vnode.h>
#include <sys/syscallvar.h>
#include <sys/xcall.h>
#include <sys/module.h>

#include <uvm/uvm_extern.h>

#include <dev/cons.h>

#include <net/if.h>

/* XXX these should eventually move to subr_autoconf.c */
static device_t finddevice(const char *);
static device_t getdisk(char *, int, int, dev_t *, int);
static device_t parsedisk(char *, int, int, dev_t *);
static const char *getwedgename(const char *, int);

/*
 * A generic linear hook.
 */
struct hook_desc {
	LIST_ENTRY(hook_desc) hk_list;
	void	(*hk_fn)(void *);
	void	*hk_arg;
};
typedef LIST_HEAD(, hook_desc) hook_list_t;

#ifdef TFTPROOT
int tftproot_dhcpboot(device_t);
#endif

dev_t	dumpcdev;	/* for savecore */

static void *
hook_establish(hook_list_t *list, void (*fn)(void *), void *arg)
{
	struct hook_desc *hd;

	hd = malloc(sizeof(*hd), M_DEVBUF, M_NOWAIT);
	if (hd == NULL)
		return (NULL);

	hd->hk_fn = fn;
	hd->hk_arg = arg;
	LIST_INSERT_HEAD(list, hd, hk_list);

	return (hd);
}

static void
hook_disestablish(hook_list_t *list, void *vhook)
{
#ifdef DIAGNOSTIC
	struct hook_desc *hd;

	LIST_FOREACH(hd, list, hk_list) {
                if (hd == vhook)
			break;
	}

	if (hd == NULL)
		panic("hook_disestablish: hook %p not established", vhook);
#endif
	LIST_REMOVE((struct hook_desc *)vhook, hk_list);
	free(vhook, M_DEVBUF);
}

static void
hook_destroy(hook_list_t *list)
{
	struct hook_desc *hd;

	while ((hd = LIST_FIRST(list)) != NULL) {
		LIST_REMOVE(hd, hk_list);
		free(hd, M_DEVBUF);
	}
}

static void
hook_proc_run(hook_list_t *list, struct proc *p)
{
	struct hook_desc *hd;

	LIST_FOREACH(hd, list, hk_list)
		((void (*)(struct proc *, void *))*hd->hk_fn)(p, hd->hk_arg);
}

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

static hook_list_t shutdownhook_list;

void *
shutdownhook_establish(void (*fn)(void *), void *arg)
{
	return hook_establish(&shutdownhook_list, fn, arg);
}

void
shutdownhook_disestablish(void *vhook)
{
	hook_disestablish(&shutdownhook_list, vhook);
}

/*
 * 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(void)
{
	struct hook_desc *dp;

	while ((dp = LIST_FIRST(&shutdownhook_list)) != NULL) {
		LIST_REMOVE(dp, hk_list);
		(*dp->hk_fn)(dp->hk_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
	}
}

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

static hook_list_t mountroothook_list;

void *
mountroothook_establish(void (*fn)(device_t), device_t dev)
{
	return hook_establish(&mountroothook_list, (void (*)(void *))fn, dev);
}

void
mountroothook_disestablish(void *vhook)
{
	hook_disestablish(&mountroothook_list, vhook);
}

void
mountroothook_destroy(void)
{
	hook_destroy(&mountroothook_list);
}

void
domountroothook(void)
{
	struct hook_desc *hd;

	LIST_FOREACH(hd, &mountroothook_list, hk_list) {
		if (hd->hk_arg == (void *)root_device) {
			(*hd->hk_fn)(hd->hk_arg);
			return;
		}
	}
}

static hook_list_t exechook_list;

void *
exechook_establish(void (*fn)(struct proc *, void *), void *arg)
{
	return hook_establish(&exechook_list, (void (*)(void *))fn, arg);
}

void
exechook_disestablish(void *vhook)
{
	hook_disestablish(&exechook_list, vhook);
}

/*
 * Run exec hooks.
 */
void
doexechooks(struct proc *p)
{
	hook_proc_run(&exechook_list, p);
}

static hook_list_t exithook_list;
extern krwlock_t exec_lock;

void *
exithook_establish(void (*fn)(struct proc *, void *), void *arg)
{
	void *rv;

	rw_enter(&exec_lock, RW_WRITER);
	rv = hook_establish(&exithook_list, (void (*)(void *))fn, arg);
	rw_exit(&exec_lock);
	return rv;
}

void
exithook_disestablish(void *vhook)
{

	rw_enter(&exec_lock, RW_WRITER);
	hook_disestablish(&exithook_list, vhook);
	rw_exit(&exec_lock);
}

/*
 * Run exit hooks.
 */
void
doexithooks(struct proc *p)
{
	hook_proc_run(&exithook_list, p);
}

static hook_list_t forkhook_list;

void *
forkhook_establish(void (*fn)(struct proc *, struct proc *))
{
	return hook_establish(&forkhook_list, (void (*)(void *))fn, NULL);
}

void
forkhook_disestablish(void *vhook)
{
	hook_disestablish(&forkhook_list, vhook);
}

/*
 * Run fork hooks.
 */
void
doforkhooks(struct proc *p2, struct proc *p1)
{
	struct hook_desc *hd;

	LIST_FOREACH(hd, &forkhook_list, hk_list) {
		((void (*)(struct proc *, struct proc *))*hd->hk_fn)
		    (p2, p1);
	}
}

/*
 * "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)(int, void *);
	void	*sfd_arg;
	char	sfd_name[16];
};

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

void *
powerhook_establish(const char *name, void (*fn)(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;
	strlcpy(ndp->sfd_name, name, sizeof(ndp->sfd_name));
	CIRCLEQ_INSERT_HEAD(&powerhook_list, ndp, sfd_list);

	aprint_error("%s: WARNING: powerhook_establish is deprecated\n", name);
	return (ndp);
}

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

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

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

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

#ifdef POWERHOOK_DEBUG
	const char *why_name;
	static const char * pwr_names[] = {PWR_NAMES};
	why_name = why < __arraycount(pwr_names) ? pwr_names[why] : "???";
#endif

	if (why == PWR_RESUME || why == PWR_SOFTRESUME) {
		CIRCLEQ_FOREACH_REVERSE(dp, &powerhook_list, sfd_list) {
#ifdef POWERHOOK_DEBUG
			printf("dopowerhooks %s: %s (%p)\n", why_name, dp->sfd_name, dp);
#endif
			(*dp->sfd_fn)(why, dp->sfd_arg);
		}
	} else {
		CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list) {
#ifdef POWERHOOK_DEBUG
			printf("dopowerhooks %s: %s (%p)\n", why_name, dp->sfd_name, dp);
#endif
			(*dp->sfd_fn)(why, dp->sfd_arg);
		}
	}

#ifdef POWERHOOK_DEBUG
	printf("dopowerhooks: %s done\n", why_name);
#endif
}

static int
isswap(device_t dv)
{
	struct dkwedge_info wi;
	struct vnode *vn;
	int error;

	if (device_class(dv) != DV_DISK || !device_is_a(dv, "dk"))
		return 0;

	if ((vn = opendisk(dv)) == NULL)
		return 0;

	error = VOP_IOCTL(vn, DIOCGWEDGEINFO, &wi, FREAD, NOCRED);
	VOP_CLOSE(vn, FREAD, NOCRED);
	vput(vn);
	if (error) {
#ifdef DEBUG_WEDGE
		printf("%s: Get wedge info returned %d\n", device_xname(dv), error);
#endif
		return 0;
	}
	return strcmp(wi.dkw_ptype, DKW_PTYPE_SWAP) == 0;
}

/*
 * Determine the root device and, if instructed to, the root file system.
 */

#include "md.h"

#if NMD > 0
extern struct cfdriver md_cd;
#ifdef MEMORY_DISK_IS_ROOT
int md_is_root = 1;
#else
int md_is_root = 0;
#endif
#endif

/*
 * The device and wedge that we booted from.  If booted_wedge is NULL,
 * the we might consult booted_partition.
 */
device_t booted_device;
device_t booted_wedge;
int booted_partition;

/*
 * Use partition letters if it's a disk class but not a wedge.
 * XXX Check for wedge is kinda gross.
 */
#define	DEV_USES_PARTITIONS(dv)						\
	(device_class((dv)) == DV_DISK &&				\
	 !device_is_a((dv), "dk"))

void
setroot(device_t bootdv, int bootpartition)
{
	device_t dv;
	deviter_t di;
	int len, majdev;
	dev_t nrootdev;
	dev_t ndumpdev = NODEV;
	char buf[128];
	const char *rootdevname;
	const char *dumpdevname;
	device_t rootdv = NULL;		/* XXX gcc -Wuninitialized */
	device_t dumpdv = NULL;
	struct ifnet *ifp;
	const char *deffsname;
	struct vfsops *vops;

#ifdef TFTPROOT
	if (tftproot_dhcpboot(bootdv) != 0)
		boothowto |= RB_ASKNAME;
#endif

#if NMD > 0
	if (md_is_root) {
		/*
		 * XXX there should be "root on md0" in the config file,
		 * but it isn't always
		 */
		bootdv = md_cd.cd_devs[0];
		bootpartition = 0;
	}
#endif

	/*
	 * If NFS is specified as the file system, and we found
	 * a DV_DISK boot device (or no boot device at all), then
	 * find a reasonable network interface for "rootspec".
	 */
	vops = vfs_getopsbyname(MOUNT_NFS);
	if (vops != NULL && strcmp(rootfstype, MOUNT_NFS) == 0 &&
	    rootspec == NULL &&
	    (bootdv == NULL || device_class(bootdv) != DV_IFNET)) {
		IFNET_FOREACH(ifp) {
			if ((ifp->if_flags &
			     (IFF_LOOPBACK|IFF_POINTOPOINT)) == 0)
				break;
		}
		if (ifp == NULL) {
			/*
			 * Can't find a suitable interface; ask the
			 * user.
			 */
			boothowto |= RB_ASKNAME;
		} else {
			/*
			 * Have a suitable interface; behave as if
			 * the user specified this interface.
			 */
			rootspec = (const char *)ifp->if_xname;
		}
	}
	if (vops != NULL)
		vfs_delref(vops);

	/*
	 * If wildcarded root and we the boot device wasn't determined,
	 * ask the user.
	 */
	if (rootspec == NULL && bootdv == NULL)
		boothowto |= RB_ASKNAME;

 top:
	if (boothowto & RB_ASKNAME) {
		device_t defdumpdv;

		for (;;) {
			printf("root device");
			if (bootdv != NULL) {
				printf(" (default %s", device_xname(bootdv));
				if (DEV_USES_PARTITIONS(bootdv))
					printf("%c", bootpartition + 'a');
				printf(")");
			}
			printf(": ");
			len = cngetsn(buf, sizeof(buf));
			if (len == 0 && bootdv != NULL) {
				strlcpy(buf, device_xname(bootdv), sizeof(buf));
				len = strlen(buf);
			}
			if (len > 0 && buf[len - 1] == '*') {
				buf[--len] = '\0';
				dv = getdisk(buf, len, 1, &nrootdev, 0);
				if (dv != NULL) {
					rootdv = dv;
					break;
				}
			}
			dv = getdisk(buf, len, bootpartition, &nrootdev, 0);
			if (dv != NULL) {
				rootdv = dv;
				break;
			}
		}

		/*
		 * Set up the default dump device.  If root is on
		 * a network device, there is no default dump
		 * device, since we don't support dumps to the
		 * network.
		 */
		if (DEV_USES_PARTITIONS(rootdv) == 0)
			defdumpdv = NULL;
		else
			defdumpdv = rootdv;

		for (;;) {
			printf("dump device");
			if (defdumpdv != NULL) {
				/*
				 * Note, we know it's a disk if we get here.
				 */
				printf(" (default %sb)", device_xname(defdumpdv));
			}
			printf(": ");
			len = cngetsn(buf, sizeof(buf));
			if (len == 0) {
				if (defdumpdv != NULL) {
					ndumpdev = MAKEDISKDEV(major(nrootdev),
					    DISKUNIT(nrootdev), 1);
				}
				dumpdv = defdumpdv;
				break;
			}
			if (len == 4 && strcmp(buf, "none") == 0) {
				dumpdv = NULL;
				break;
			}
			dv = getdisk(buf, len, 1, &ndumpdev, 1);
			if (dv != NULL) {
				dumpdv = dv;
				break;
			}
		}

		rootdev = nrootdev;
		dumpdev = ndumpdev;

		for (vops = LIST_FIRST(&vfs_list); vops != NULL;
		     vops = LIST_NEXT(vops, vfs_list)) {
			if (vops->vfs_mountroot != NULL &&
			    strcmp(rootfstype, vops->vfs_name) == 0)
			break;
		}

		if (vops == NULL) {
			deffsname = "generic";
		} else
			deffsname = vops->vfs_name;

		for (;;) {
			printf("file system (default %s): ", deffsname);
			len = cngetsn(buf, sizeof(buf));
			if (len == 0) {
				if (strcmp(deffsname, "generic") == 0)
					rootfstype = ROOT_FSTYPE_ANY;
				break;
			}
			if (len == 4 && strcmp(buf, "halt") == 0)
				cpu_reboot(RB_HALT, NULL);
			else if (len == 6 && strcmp(buf, "reboot") == 0)
				cpu_reboot(0, NULL);
#if defined(DDB)
			else if (len == 3 && strcmp(buf, "ddb") == 0) {
				console_debugger();
			}
#endif
			else if (len == 7 && strcmp(buf, "generic") == 0) {
				rootfstype = ROOT_FSTYPE_ANY;
				break;
			}
			vops = vfs_getopsbyname(buf);
			if (vops == NULL || vops->vfs_mountroot == NULL) {
				printf("use one of: generic");
				for (vops = LIST_FIRST(&vfs_list);
				     vops != NULL;
				     vops = LIST_NEXT(vops, vfs_list)) {
					if (vops->vfs_mountroot != NULL)
						printf(" %s", vops->vfs_name);
				}
				if (vops != NULL)
					vfs_delref(vops);
#if defined(DDB)
				printf(" ddb");
#endif
				printf(" halt reboot\n");
			} else {
				/*
				 * XXX If *vops gets freed between here and
				 * the call to mountroot(), rootfstype will
				 * point to something unexpected.  But in
				 * this case the system will fail anyway.
				 */
				rootfstype = vops->vfs_name;
				vfs_delref(vops);
				break;
			}
		}

	} else if (rootspec == NULL) {
		/*
		 * Wildcarded root; use the boot device.
		 */
		rootdv = bootdv;

		if (bootdv)
			majdev = devsw_name2blk(device_xname(bootdv), NULL, 0);
		else
			majdev = -1;
		if (majdev >= 0) {
			/*
			 * Root is on a disk.  `bootpartition' is root,
			 * unless the device does not use partitions.
			 */
			if (DEV_USES_PARTITIONS(bootdv))
				rootdev = MAKEDISKDEV(majdev,
						      device_unit(bootdv),
						      bootpartition);
			else
				rootdev = makedev(majdev, device_unit(bootdv));
		}
	} else {

		/*
		 * `root on <dev> ...'
		 */

		/*
		 * If it's a network interface, we can bail out
		 * early.
		 */
		dv = finddevice(rootspec);
		if (dv != NULL && device_class(dv) == DV_IFNET) {
			rootdv = dv;
			goto haveroot;
		}

		if (rootdev == NODEV &&
		    device_class(dv) == DV_DISK && device_is_a(dv, "dk") &&
		    (majdev = devsw_name2blk(device_xname(dv), NULL, 0)) >= 0)
			rootdev = makedev(majdev, device_unit(dv));

		rootdevname = devsw_blk2name(major(rootdev));
		if (rootdevname == NULL) {
			printf("unknown device major 0x%llx\n",
			    (unsigned long long)rootdev);
			boothowto |= RB_ASKNAME;
			goto top;
		}
		memset(buf, 0, sizeof(buf));
		snprintf(buf, sizeof(buf), "%s%llu", rootdevname,
		    (unsigned long long)DISKUNIT(rootdev));

		rootdv = finddevice(buf);
		if (rootdv == NULL) {
			printf("device %s (0x%llx) not configured\n",
			    buf, (unsigned long long)rootdev);
			boothowto |= RB_ASKNAME;
			goto top;
		}
	}

 haveroot:

	root_device = rootdv;

	switch (device_class(rootdv)) {
	case DV_IFNET:
	case DV_DISK:
		aprint_normal("root on %s", device_xname(rootdv));
		if (DEV_USES_PARTITIONS(rootdv))
			aprint_normal("%c", (int)DISKPART(rootdev) + 'a');
		break;

	default:
		printf("can't determine root device\n");
		boothowto |= RB_ASKNAME;
		goto top;
	}

	/*
	 * Now configure the dump device.
	 *
	 * If we haven't figured out the dump device, do so, with
	 * the following rules:
	 *
	 *	(a) We already know dumpdv in the RB_ASKNAME case.
	 *
	 *	(b) If dumpspec is set, try to use it.  If the device
	 *	    is not available, punt.
	 *
	 *	(c) If dumpspec is not set, the dump device is
	 *	    wildcarded or unspecified.  If the root device
	 *	    is DV_IFNET, punt.  Otherwise, use partition b
	 *	    of the root device.
	 */

	if (boothowto & RB_ASKNAME) {		/* (a) */
		if (dumpdv == NULL)
			goto nodumpdev;
	} else if (dumpspec != NULL) {		/* (b) */
		if (strcmp(dumpspec, "none") == 0 || dumpdev == NODEV) {
			/*
			 * Operator doesn't want a dump device.
			 * Or looks like they tried to pick a network
			 * device.  Oops.
			 */
			goto nodumpdev;
		}

		dumpdevname = devsw_blk2name(major(dumpdev));
		if (dumpdevname == NULL)
			goto nodumpdev;
		memset(buf, 0, sizeof(buf));
		snprintf(buf, sizeof(buf), "%s%llu", dumpdevname,
		    (unsigned long long)DISKUNIT(dumpdev));

		dumpdv = finddevice(buf);
		if (dumpdv == NULL) {
			/*
			 * Device not configured.
			 */
			goto nodumpdev;
		}
	} else {				/* (c) */
		if (DEV_USES_PARTITIONS(rootdv) == 0) {
			for (dv = deviter_first(&di, DEVITER_F_ROOT_FIRST);
			     dv != NULL;
			     dv = deviter_next(&di))
				if (isswap(dv))
					break;
			deviter_release(&di);
			if (dv == NULL)
				goto nodumpdev;

			majdev = devsw_name2blk(device_xname(dv), NULL, 0);
			if (majdev < 0)
				goto nodumpdev;
			dumpdv = dv;
			dumpdev = makedev(majdev, device_unit(dumpdv));
		} else {
			dumpdv = rootdv;
			dumpdev = MAKEDISKDEV(major(rootdev),
			    device_unit(dumpdv), 1);
		}
	}

	dumpcdev = devsw_blk2chr(dumpdev);
	aprint_normal(" dumps on %s", device_xname(dumpdv));
	if (DEV_USES_PARTITIONS(dumpdv))
		aprint_normal("%c", (int)DISKPART(dumpdev) + 'a');
	aprint_normal("\n");
	return;

 nodumpdev:
	dumpdev = NODEV;
	dumpcdev = NODEV;
	aprint_normal("\n");
}

static device_t
finddevice(const char *name)
{
	const char *wname;

	if ((wname = getwedgename(name, strlen(name))) != NULL)
		return dkwedge_find_by_wname(wname);

	return device_find_by_xname(name);
}

static device_t
getdisk(char *str, int len, int defpart, dev_t *devp, int isdump)
{
	device_t dv;
	deviter_t di;

	if ((dv = parsedisk(str, len, defpart, devp)) == NULL) {
		printf("use one of:");
		for (dv = deviter_first(&di, DEVITER_F_ROOT_FIRST); dv != NULL;
		     dv = deviter_next(&di)) {
			if (DEV_USES_PARTITIONS(dv))
				printf(" %s[a-%c]", device_xname(dv),
				    'a' + MAXPARTITIONS - 1);
			else if (device_class(dv) == DV_DISK)
				printf(" %s", device_xname(dv));
			if (isdump == 0 && device_class(dv) == DV_IFNET)
				printf(" %s", device_xname(dv));
		}
		deviter_release(&di);
		dkwedge_print_wnames();
		if (isdump)
			printf(" none");
#if defined(DDB)
		printf(" ddb");
#endif
		printf(" halt reboot\n");
	}
	return dv;
}

static const char *
getwedgename(const char *name, int namelen)
{
	const char *wpfx = "wedge:";
	const int wpfxlen = strlen(wpfx);

	if (namelen < wpfxlen || strncmp(name, wpfx, wpfxlen) != 0)
		return NULL;

	return name + wpfxlen;
}

static device_t
parsedisk(char *str, int len, int defpart, dev_t *devp)
{
	device_t dv;
	const char *wname;
	char *cp, c;
	int majdev, part;
	if (len == 0)
		return (NULL);

	if (len == 4 && strcmp(str, "halt") == 0)
		cpu_reboot(RB_HALT, NULL);
	else if (len == 6 && strcmp(str, "reboot") == 0)
		cpu_reboot(0, NULL);
#if defined(DDB)
	else if (len == 3 && strcmp(str, "ddb") == 0)
		console_debugger();
#endif

	cp = str + len - 1;
	c = *cp;

	if ((wname = getwedgename(str, len)) != NULL) {
		if ((dv = dkwedge_find_by_wname(wname)) == NULL)
			return NULL;
		part = defpart;
		goto gotdisk;
	} else if (c >= 'a' && c <= ('a' + MAXPARTITIONS - 1)) {
		part = c - 'a';
		*cp = '\0';
	} else
		part = defpart;

	dv = finddevice(str);
	if (dv != NULL) {
		if (device_class(dv) == DV_DISK) {
 gotdisk:
			majdev = devsw_name2blk(device_xname(dv), NULL, 0);
			if (majdev < 0)
				panic("parsedisk");
			if (DEV_USES_PARTITIONS(dv))
				*devp = MAKEDISKDEV(majdev, device_unit(dv),
						    part);
			else
				*devp = makedev(majdev, device_unit(dv));
		}

		if (device_class(dv) == DV_IFNET)
			*devp = NODEV;
	}

	*cp = c;
	return (dv);
}

/*
 * Return true if system call tracing is enabled for the specified process.
 */
bool
trace_is_enabled(struct proc *p)
{
#ifdef SYSCALL_DEBUG
	return (true);
#endif
#ifdef KTRACE
	if (ISSET(p->p_traceflag, (KTRFAC_SYSCALL | KTRFAC_SYSRET)))
		return (true);
#endif
#ifdef PTRACE
	if (ISSET(p->p_slflag, PSL_SYSCALL))
		return (true);
#endif

	return (false);
}

/*
 * Start trace of particular system call. If process is being traced,
 * this routine is called by MD syscall dispatch code just before
 * a system call is actually executed.
 */
int
trace_enter(register_t code, const register_t *args, int narg)
{
#ifdef SYSCALL_DEBUG
	scdebug_call(code, args);
#endif /* SYSCALL_DEBUG */

	ktrsyscall(code, args, narg);

#ifdef PTRACE
	if ((curlwp->l_proc->p_slflag & (PSL_SYSCALL|PSL_TRACED)) ==
	    (PSL_SYSCALL|PSL_TRACED))
		process_stoptrace();
#endif
	return 0;
}

/*
 * End trace of particular system call. If process is being traced,
 * this routine is called by MD syscall dispatch code just after
 * a system call finishes.
 * MD caller guarantees the passed 'code' is within the supported
 * system call number range for emulation the process runs under.
 */
void
trace_exit(register_t code, register_t rval[], int error)
{
#ifdef SYSCALL_DEBUG
	scdebug_ret(code, error, rval);
#endif /* SYSCALL_DEBUG */

	ktrsysret(code, error, rval);

#ifdef PTRACE
	if ((curlwp->l_proc->p_slflag & (PSL_SYSCALL|PSL_TRACED)) ==
	    (PSL_SYSCALL|PSL_TRACED))
		process_stoptrace();
#endif
}

int
syscall_establish(const struct emul *em, const struct syscall_package *sp)
{
	struct sysent *sy;
	int i;

	KASSERT(mutex_owned(&module_lock));

	if (em == NULL) {
		em = &emul_netbsd;
	}
	sy = em->e_sysent;

	/*
	 * Ensure that all preconditions are valid, since this is
	 * an all or nothing deal.  Once a system call is entered,
	 * it can become busy and we could be unable to remove it
	 * on error.
	 */
	for (i = 0; sp[i].sp_call != NULL; i++) {
		if (sy[sp[i].sp_code].sy_call != sys_nomodule) {
#ifdef DIAGNOSTIC
			printf("syscall %d is busy\n", sp[i].sp_code);
#endif
			return EBUSY;
		}
	}
	/* Everything looks good, patch them in. */
	for (i = 0; sp[i].sp_call != NULL; i++) {
		sy[sp[i].sp_code].sy_call = sp[i].sp_call;
	}

	return 0;
}

int
syscall_disestablish(const struct emul *em, const struct syscall_package *sp)
{
	struct sysent *sy;
	uint64_t where;
	lwp_t *l;
	int i;

	KASSERT(mutex_owned(&module_lock));

	if (em == NULL) {
		em = &emul_netbsd;
	}
	sy = em->e_sysent;

	/*
	 * First, patch the system calls to sys_nomodule to gate further
	 * activity.
	 */
	for (i = 0; sp[i].sp_call != NULL; i++) {
		KASSERT(sy[sp[i].sp_code].sy_call == sp[i].sp_call);
		sy[sp[i].sp_code].sy_call = sys_nomodule;
	}

	/*
	 * Run a cross call to cycle through all CPUs.  This does two
	 * things: lock activity provides a barrier and makes our update
	 * of sy_call visible to all CPUs, and upon return we can be sure
	 * that we see pertinent values of l_sysent posted by remote CPUs.
	 */
	where = xc_broadcast(0, (xcfunc_t)nullop, NULL, NULL);
	xc_wait(where);

	/*
	 * Now it's safe to check l_sysent.  Run through all LWPs and see
	 * if anyone is still using the system call.
	 */
	for (i = 0; sp[i].sp_call != NULL; i++) {
		mutex_enter(proc_lock);
		LIST_FOREACH(l, &alllwp, l_list) {
			if (l->l_sysent == &sy[sp[i].sp_code]) {
				break;
			}
		}
		mutex_exit(proc_lock);
		if (l == NULL) {
			continue;
		}
		/*
		 * We lose: one or more calls are still in use.  Put back
		 * the old entrypoints and act like nothing happened.
		 * When we drop module_lock, any system calls held in
		 * sys_nomodule() will be restarted.
		 */
		for (i = 0; sp[i].sp_call != NULL; i++) {
			sy[sp[i].sp_code].sy_call = sp[i].sp_call;
		}
		return EBUSY;
	}

	return 0;
}