freebsd-dev/sys/miscfs/kernfs/kernfs_vfsops.c

/*
 * 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. 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.
 *
 *	@(#)kernfs_vfsops.c	8.10 (Berkeley) 5/14/95
 * $FreeBSD$
 */

/*
 * Kernel params Filesystem
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/malloc.h>

#include <miscfs/kernfs/kernfs.h>

static MALLOC_DEFINE(M_KERNFSMNT, "KERNFS mount", "KERNFS mount structure");

dev_t rrootdev = NODEV;

static void	kernfs_get_rrootdev __P((void));
static int	kernfs_mount __P((struct mount *mp, char *path, caddr_t data,
				  struct nameidata *ndp, struct proc *p));
static int	kernfs_unmount __P((struct mount *mp, int mntflags,
				  struct proc *p));
static int	kernfs_root __P((struct mount *mp, struct vnode **vpp));
static int	kernfs_statfs __P((struct mount *mp, struct statfs *sbp,
				   struct proc *p));

static void
kernfs_get_rrootdev()
{
	static int tried = 0;
	struct cdevsw *sw;

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

	sw = devsw(rootdev);
	if (!sw)
		return;
	if (rootdev == NODEV)
		return;
	rrootdev = makedev(sw->d_maj, minor(rootdev));
}

/*
 * Mount the Kernel params filesystem
 */
static int
kernfs_mount(mp, path, data, ndp, p)
	struct mount *mp;
	char *path;
	caddr_t data;
	struct nameidata *ndp;
	struct proc *p;
{
	int error = 0;
	u_int size;
	struct kernfs_mount *fmp;
	struct vnode *rvp;

#ifdef DEBUG
	printf("kernfs_mount(mp = %p)\n", (void *)mp);
#endif

	/*
	 * Update is a no-op
	 */
	if (mp->mnt_flag & MNT_UPDATE)
		return (EOPNOTSUPP);

	MALLOC(fmp, struct kernfs_mount *, sizeof(struct kernfs_mount),
				M_KERNFSMNT, M_WAITOK);	/* XXX */

	error = getnewvnode(VT_KERNFS, mp, kernfs_vnodeop_p, &rvp);	/* XXX */
	if (error) {
		FREE(fmp, M_KERNFSMNT);
		return (error);
	}

	rvp->v_type = VDIR;
	rvp->v_flag |= VROOT;
#ifdef DEBUG
	printf("kernfs_mount: root vp = %p\n", (void *)rvp);
#endif
	fmp->kf_root = rvp;
	mp->mnt_flag |= MNT_LOCAL;
	mp->mnt_data = (qaddr_t) fmp;
	vfs_getnewfsid(mp);

	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
	bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
	bcopy("kernfs", mp->mnt_stat.f_mntfromname, sizeof("kernfs"));
	(void)kernfs_statfs(mp, &mp->mnt_stat, p);
#ifdef DEBUG
	printf("kernfs_mount: at %s\n", mp->mnt_stat.f_mntonname);
#endif

	kernfs_get_rrootdev();
	return (0);
}

static int
kernfs_unmount(mp, mntflags, p)
	struct mount *mp;
	int mntflags;
	struct proc *p;
{
	int error;
	int flags = 0;
	struct vnode *rootvp = VFSTOKERNFS(mp)->kf_root;

#ifdef DEBUG
	printf("kernfs_unmount(mp = %p)\n", (void *)mp);
#endif

	if (mntflags & MNT_FORCE)
		flags |= FORCECLOSE;

	/*
	 * Clear out buffer cache.  I don't think we
	 * ever get anything cached at this level at the
	 * moment, but who knows...
	 */
	if (rootvp->v_usecount > 1)
		return (EBUSY);
#ifdef DEBUG
	printf("kernfs_unmount: calling vflush\n");
#endif
	error = vflush(mp, rootvp, flags);
	if (error)
		return (error);

#ifdef DEBUG
	vprint("kernfs root", rootvp);
#endif
	/*
	 * Release reference on underlying root vnode
	 */
	vrele(rootvp);
	/*
	 * And blow it away for future re-use
	 */
	vgone(rootvp);
	/*
	 * Finally, throw away the kernfs_mount structure
	 */
	free(mp->mnt_data, M_KERNFSMNT);	/* XXX */
	mp->mnt_data = 0;
	return 0;
}

static int
kernfs_root(mp, vpp)
	struct mount *mp;
	struct vnode **vpp;
{
	struct proc *p = curproc;	/* XXX */
	struct vnode *vp;

#ifdef DEBUG
	printf("kernfs_root(mp = %p)\n", (void *)mp);
#endif

	/*
	 * Return locked reference to root.
	 */
	vp = VFSTOKERNFS(mp)->kf_root;
	VREF(vp);
	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
	*vpp = vp;
	return (0);
}

static int
kernfs_statfs(mp, sbp, p)
	struct mount *mp;
	struct statfs *sbp;
	struct proc *p;
{
#ifdef DEBUG
	printf("kernfs_statfs(mp = %p)\n", (void *)mp);
#endif

	sbp->f_flags = 0;
	sbp->f_bsize = DEV_BSIZE;
	sbp->f_iosize = DEV_BSIZE;
	sbp->f_blocks = 2;		/* 1K to keep df happy */
	sbp->f_bfree = 0;
	sbp->f_bavail = 0;
	sbp->f_files = 0;
	sbp->f_ffree = 0;
	if (sbp != &mp->mnt_stat) {
		sbp->f_type = mp->mnt_vfc->vfc_typenum;
		bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
	}
	return (0);
}

static struct vfsops kernfs_vfsops = {
	kernfs_mount,
	vfs_stdstart,
	kernfs_unmount,
	kernfs_root,
	vfs_stdquotactl,
	kernfs_statfs,
	vfs_stdsync,
	vfs_stdvget,
	vfs_stdfhtovp,
	vfs_stdcheckexp,
	vfs_stdvptofh,
	vfs_stdinit,
};

VFS_SET(kernfs_vfsops, kernfs, VFCF_SYNTHETIC);