text: /*	$OpenBSD: fdesc_vfsops.c,v 1.6 1998/02/08 22:41:37 tholo Exp $	*/
  /*	$NetBSD: fdesc_vfsops.c,v 1.21 1996/02/09 22:40:07 christos Exp $	*/
  
  /*
   * 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.
   *
   * 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.
   *
   *	@(#)fdesc_vfsops.c	8.4 (Berkeley) 1/21/94
   *
   * #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>
  
  int	fdesc_mount __P((struct mount *, const char *, caddr_t,
  			 struct nameidata *, struct proc *));
  int	fdesc_start __P((struct mount *, int, struct proc *));
  int	fdesc_unmount __P((struct mount *, int, struct proc *));
  int	fdesc_root __P((struct mount *, struct vnode **));
  int	fdesc_quotactl __P((struct mount *, int, uid_t, caddr_t,
  			    struct proc *));
  int	fdesc_statfs __P((struct mount *, struct statfs *, struct proc *));
  int	fdesc_sync __P((struct mount *, int, struct ucred *, struct proc *));
  int	fdesc_vget __P((struct mount *, ino_t, struct vnode **));
  int	fdesc_fhtovp __P((struct mount *, struct fid *, struct mbuf *,
  			  struct vnode **, int *, struct ucred **));
  int	fdesc_vptofh __P((struct vnode *, struct fid *));
  
  /*
   * Mount the per-process file descriptors (/dev/fd)
   */
  int
  fdesc_mount(mp, path, data, ndp, p)
  	struct mount *mp;
  	const char *path;
  	caddr_t data;
  	struct nameidata *ndp;
  	struct proc *p;
  {
  	int error = 0;
  	size_t 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;
  	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)) != 0)
  		return (error);
  
  	/*
  	 * 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);
  }
  
  int
  fdesc_root(mp, vpp)
  	struct mount *mp;
  	struct vnode **vpp;
  {
  	struct vnode *vp;
  	struct proc *p = curproc;         /* XXX */
  	/*
  	 * Return locked reference to root.
  	 */
  	vp = VFSTOFDESC(mp)->f_root;
  	VREF(vp);
  	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
  	*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);
  
  #ifdef COMPAT_09
  	sbp->f_type = 6;
  #else
  	sbp->f_type = 0;
  #endif
  	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);
  	}
  	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
  	return (0);
  }
  
  /*ARGSUSED*/
  int
  fdesc_sync(mp, waitfor, uc, p)
  	struct mount *mp;
  	int waitfor;
  	struct ucred *uc;
  	struct proc *p;
  {
  
  	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
  };
  
  