check for forcible unmount at syscall level

[unix-history] / usr / src / sys / miscfs / fdesc / fdesc_vfsops.c

/*
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)fdesc_vfsops.c	8.8 (Berkeley) %G%
 *
 * $Id: fdesc_vfsops.c,v 1.9 1993/04/06 15:28:33 jsp Exp $
 */

/*
 * /dev/fd Filesystem
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/filedesc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <miscfs/fdesc/fdesc.h>

/*
 * Mount the per-process file descriptors (/dev/fd)
 */
int
fdesc_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 fdescmount *fmp;
	struct vnode *rvp;

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

	error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp);
	if (error)
		return (error);

	MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount),
				M_UFSMNT, M_WAITOK);	/* XXX */
	rvp->v_type = VDIR;
	rvp->v_flag |= VROOT;
	fmp->f_root = rvp;
	/* XXX -- don't mark as local to work around fts() problems */
	/*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("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc"));
	return (0);
}

int
fdesc_start(mp, flags, p)
	struct mount *mp;
	int flags;
	struct proc *p;
{
	return (0);
}

int
fdesc_unmount(mp, mntflags, p)
	struct mount *mp;
	int mntflags;
	struct proc *p;
{
	int error;
	int flags = 0;
	struct vnode *rootvp = VFSTOFDESC(mp)->f_root;

	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);
	if (error = vflush(mp, rootvp, flags))
		return (error);

	/*
	 * Release reference on underlying root vnode
	 */
	vrele(rootvp);
	/*
	 * And blow it away for future re-use
	 */
	VOP_REVOKE(rootvp, 0);
	/*
	 * Finally, throw away the fdescmount structure
	 */
	free(mp->mnt_data, M_UFSMNT);	/* XXX */
	mp->mnt_data = 0;

	return (0);
}

int
fdesc_root(mp, vpp)
	struct mount *mp;
	struct vnode **vpp;
{
	struct vnode *vp;

	/*
	 * Return locked reference to root.
	 */
	vp = VFSTOFDESC(mp)->f_root;
	VREF(vp);
	VOP_LOCK(vp);
	*vpp = vp;
	return (0);
}

int
fdesc_statfs(mp, sbp, p)
	struct mount *mp;
	struct statfs *sbp;
	struct proc *p;
{
	struct filedesc *fdp;
	int lim;
	int i;
	int last;
	int freefd;

	/*
	 * Compute number of free file descriptors.
	 * [ Strange results will ensue if the open file
	 * limit is ever reduced below the current number
	 * of open files... ]
	 */
	lim = p->p_rlimit[RLIMIT_NOFILE].rlim_cur;
	fdp = p->p_fd;
	last = min(fdp->fd_nfiles, lim);
	freefd = 0;
	for (i = fdp->fd_freefile; i < last; i++)
		if (fdp->fd_ofiles[i] == NULL)
			freefd++;

	/*
	 * Adjust for the fact that the fdesc array may not
	 * have been fully allocated yet.
	 */
	if (fdp->fd_nfiles < lim)
		freefd += (lim - fdp->fd_nfiles);

	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 = lim + 1;		/* Allow for "." */
	sbp->f_ffree = freefd;		/* See comments above */
	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);
}

int
fdesc_sync(mp, waitfor)
	struct mount *mp;
	int waitfor;
{

	return (0);
}

#define fdesc_fhtovp ((int (*) __P((struct mount *, struct fid *, \
	    struct mbuf *, struct vnode **, int *, struct ucred **)))eopnotsupp)
#define fdesc_quotactl ((int (*) __P((struct mount *, int, uid_t, caddr_t, \
	    struct proc *)))eopnotsupp)
#define fdesc_sysctl ((int (*) __P((int *, u_int, void *, size_t *, void *, \
	    size_t, struct proc *)))eopnotsupp)
#define fdesc_vget ((int (*) __P((struct mount *, ino_t, struct vnode **))) \
	    eopnotsupp)
#define fdesc_vptofh ((int (*) __P((struct vnode *, struct fid *)))eopnotsupp)

struct vfsops fdesc_vfsops = {
	fdesc_mount,
	fdesc_start,
	fdesc_unmount,
	fdesc_root,
	fdesc_quotactl,
	fdesc_statfs,
	fdesc_sync,
	fdesc_vget,
	fdesc_fhtovp,
	fdesc_vptofh,
	fdesc_init,
	fdesc_sysctl,
};