miscfs/kernfs/kernfs_vfsops.c

/*	$NetBSD: kernfs_vfsops.c,v 1.92 2014/02/25 18:30:11 pooka Exp $	*/

/*
 * Copyright (c) 1992, 1993, 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * 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.
 *
 *	@(#)kernfs_vfsops.c	8.10 (Berkeley) 5/14/95
 */

/*
 * Kernel params Filesystem
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kernfs_vfsops.c,v 1.92 2014/02/25 18:30:11 pooka Exp $");

#ifdef _KERNEL_OPT
#include "opt_compat_netbsd.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/dirent.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/kauth.h>
#include <sys/module.h>

#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
#include <miscfs/kernfs/kernfs.h>

MODULE(MODULE_CLASS_VFS, kernfs, NULL);

MALLOC_JUSTDEFINE(M_KERNFSMNT, "kernfs mount", "kernfs mount structures");

dev_t rrootdev = NODEV;

VFS_PROTOS(kernfs);

void	kernfs_get_rrootdev(void);

static struct sysctllog *kernfs_sysctl_log;

void
kernfs_init(void)
{

	malloc_type_attach(M_KERNFSMNT);
	kernfs_hashinit();
}

void
kernfs_reinit(void)
{
	kernfs_hashreinit();
}

void
kernfs_done(void)
{

	kernfs_hashdone();
	malloc_type_detach(M_KERNFSMNT);
}

void
kernfs_get_rrootdev(void)
{
	static int tried = 0;

	if (tried) {
		/* Already did it once. */
		return;
	}
	tried = 1;

	if (rootdev == NODEV)
		return;
	rrootdev = devsw_blk2chr(rootdev);
	if (rrootdev != NODEV)
		return;
	rrootdev = NODEV;
	printf("kernfs_get_rrootdev: no raw root device\n");
}

/*
 * Mount the Kernel params filesystem
 */
int
kernfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
{
	struct lwp *l = curlwp;
	int error = 0;
	struct kernfs_mount *fmp;

	if (UIO_MX & (UIO_MX - 1)) {
		log(LOG_ERR, "kernfs: invalid directory entry size");
		return (EINVAL);
	}

	if (mp->mnt_flag & MNT_GETARGS) {
		*data_len = 0;
		return 0;
	}
	/*
	 * Update is a no-op
	 */
	if (mp->mnt_flag & MNT_UPDATE)
		return (EOPNOTSUPP);

	fmp = malloc(sizeof(struct kernfs_mount), M_KERNFSMNT, M_WAITOK|M_ZERO);
	TAILQ_INIT(&fmp->nodelist);

	mp->mnt_stat.f_namemax = KERNFS_MAXNAMLEN;
	mp->mnt_flag |= MNT_LOCAL;
	mp->mnt_data = fmp;
	vfs_getnewfsid(mp);

	if ((error = set_statvfs_info(path, UIO_USERSPACE, "kernfs",
	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
		free(fmp, M_KERNFSMNT);
		return error;
	}

	kernfs_get_rrootdev();
	return 0;
}

int
kernfs_start(struct mount *mp, int flags)
{

	return (0);
}

int
kernfs_unmount(struct mount *mp, int mntflags)
{
	int error;
	int flags = 0;

	if (mntflags & MNT_FORCE)
		flags |= FORCECLOSE;

	if ((error = vflush(mp, 0, flags)) != 0)
		return (error);

	/*
	 * Finally, throw away the kernfs_mount structure
	 */
	free(mp->mnt_data, M_KERNFSMNT);
	mp->mnt_data = NULL;
	return (0);
}

int
kernfs_root(struct mount *mp, struct vnode **vpp)
{

	/* setup "." */
	return (kernfs_allocvp(mp, vpp, KFSkern, &kern_targets[0], 0));
}

/*ARGSUSED*/
int
kernfs_sync(struct mount *mp, int waitfor,
    kauth_cred_t uc)
{

	return (0);
}

/*
 * Kernfs flat namespace lookup.
 * Currently unsupported.
 */
int
kernfs_vget(struct mount *mp, ino_t ino,
    struct vnode **vpp)
{

	return (EOPNOTSUPP);
}

extern const struct vnodeopv_desc kernfs_vnodeop_opv_desc;

const struct vnodeopv_desc * const kernfs_vnodeopv_descs[] = {
	&kernfs_vnodeop_opv_desc,
	NULL,
};

struct vfsops kernfs_vfsops = {
	MOUNT_KERNFS,
	0,
	kernfs_mount,
	kernfs_start,
	kernfs_unmount,
	kernfs_root,
	(void *)eopnotsupp,		/* vfs_quotactl */
	genfs_statvfs,
	kernfs_sync,
	kernfs_vget,
	(void *)eopnotsupp,		/* vfs_fhtovp */
	(void *)eopnotsupp,		/* vfs_vptofh */
	kernfs_init,
	kernfs_reinit,
	kernfs_done,
	NULL,				/* vfs_mountroot */
	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
	vfs_stdextattrctl,
	(void *)eopnotsupp,		/* vfs_suspendctl */
	genfs_renamelock_enter,
	genfs_renamelock_exit,
	(void *)eopnotsupp,
	kernfs_vnodeopv_descs,
	0,
	{ NULL, NULL },
};

static int
kernfs_modcmd(modcmd_t cmd, void *arg)
{
	int error;

	switch (cmd) {
	case MODULE_CMD_INIT:
		error = vfs_attach(&kernfs_vfsops);
		if (error != 0)
			break;
		sysctl_createv(&kernfs_sysctl_log, 0, NULL, NULL,
			       CTLFLAG_PERMANENT,
			       CTLTYPE_NODE, "kernfs",
			       SYSCTL_DESCR("/kern file system"),
			       NULL, 0, NULL, 0,
			       CTL_VFS, 11, CTL_EOL);
		/*
		 * XXX the "11" above could be dynamic, thereby eliminating one
		 * more instance of the "number to vfs" mapping problem, but
		 * "11" is the order as taken from sys/mount.h
		 */
		break;
	case MODULE_CMD_FINI:
		error = vfs_detach(&kernfs_vfsops);
		if (error != 0)
			break;
		sysctl_teardown(&kernfs_sysctl_log);
		break;
	default:
		error = ENOTTY;
		break;
	}

	return (error);
}