NetBSD/sys/miscfs/fdesc/fdesc_vfsops.c

/*
 * Copyright (c) 1992 The Regents of the University of California
 * Copyright (c) 1990, 1992 Jan-Simon Pendry
 * All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * %sccs.redist.c%
 *
 *	%W% (Berkeley) %G%
 *
 * $Id: fdesc_vfsops.c,v 1.1 1993/03/23 23:56:33 cgd Exp $
 */

/*
 * /dev/fd Filesystem
 */

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

static u_short fdesc_mntid;

fdesc_init()
{
#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_init\n");		/* printed during system boot */
#endif
}

/*
 * Mount the per-process file descriptors (/dev/fd)
 */
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;

#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_mount(mp = %x)\n", mp);
#endif

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

	error = getnewvnode(VT_UFS, mp, &fdesc_vnodeops, &rvp);	/* XXX */
	if (error)
		return (error);

	fmp = (struct fdescmount *) malloc(sizeof(struct fdescmount),
				 M_UFSMNT, M_WAITOK);	/* XXX */
	rvp->v_type = VDIR;
	rvp->v_flag |= VROOT;
	/*VTOFDESC(rvp)->f_isroot = 1;*/
#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_mount: root vp = %x\n", rvp);
#endif
	fmp->f_root = rvp;
	mp->mnt_flag |= MNT_LOCAL;
	mp->mnt_data = (qaddr_t) fmp;
	getnewfsid(mp, MOUNT_FDESC);

	(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"));
#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_mount: at %s\n", mp->mnt_stat.f_mntonname);
#endif
	return (0);
}

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

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

#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_unmount(mp = %x)\n", mp);
#endif

	if (mntflags & MNT_FORCE) {
		/* fdesc can never be rootfs so don't check for it */
		if (!doforce)
			return (EINVAL);
		flags |= FORCECLOSE;
	}

	/*
	 * Clear out buffer cache.  I don't think we
	 * ever get anything cached at this level at the
	 * moment, but who knows...
	 */
#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_unmount: calling mntflushbuf\n");
#endif
	mntflushbuf(mp, 0); 
#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_unmount: calling mntinvalbuf\n");
#endif
	if (mntinvalbuf(mp, 1))
		return (EBUSY);
	if (rootvp->v_usecount > 1)
		return (EBUSY);
#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_unmount: calling vflush\n");
#endif
	if (error = vflush(mp, rootvp, flags))
		return (error);

#ifdef FDESC_DIAGNOSTIC
	vprint("fdesc 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 fdescmount structure
	 */
	free(mp->mnt_data, M_UFSMNT);	/* XXX */
	mp->mnt_data = 0;
	return 0;
}

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

#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_root(mp = %x)\n", mp);
#endif

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

fdesc_quotactl(mp, cmd, uid, arg, p)
	struct mount *mp;
	int cmd;
	uid_t uid;
	caddr_t arg;
	struct proc *p;
{
	return (EOPNOTSUPP);
}

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;

#ifdef FDESC_DIAGNOSTIC
	printf("fdesc_statfs(mp = %x)\n", mp);
#endif

	/*
	 * 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_OFILE].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_type = MOUNT_FDESC;
	sbp->f_flags = 0;
	sbp->f_fsize = DEV_BSIZE;
	sbp->f_bsize = 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) {
		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);
}

fdesc_sync(mp, waitfor)
	struct mount *mp;
	int waitfor;
{
	return (0);
}

fdesc_fhtovp(mp, fhp, vpp)
	struct mount *mp;
	struct fid *fhp;
	struct vnode **vpp;
{
	return (EOPNOTSUPP);
}

fdesc_vptofh(vp, fhp)
	struct vnode *vp;
	struct fid *fhp;
{
	return (EOPNOTSUPP);
}

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