usr/src/sys/miscfs/fdesc/fdesc_vfsops.c

/*
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 * 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      8.1 (Berkeley) 6/10/93
 *
 * $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>

dev_t devctty;

fdesc_init()
{
#ifdef FDESC_DIAGNOSTIC
        printf("fdesc_init\n");         /* printed during system boot */
#endif
        devctty = makedev(nchrdev, 0);
}

/*
 * 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 = 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;
#ifdef FDESC_DIAGNOSTIC
        printf("fdesc_mount: root vp = %x\n", rvp);
#endif
        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;
        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...
         */
#if 0
#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);
#endif
        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_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_type = MOUNT_FDESC;
        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) {
                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 flat namespace lookup.
 * Currently unsupported.
 */
fdesc_vget(mp, ino, vpp)
        struct mount *mp;
        ino_t ino;
        struct vnode **vpp;
{

        return (EOPNOTSUPP);
}


fdesc_fhtovp(mp, fhp, setgen, vpp)
        struct mount *mp;
        struct fid *fhp;
        int setgen;
        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_vget,
        fdesc_fhtovp,
        fdesc_vptofh,
        fdesc_init,
};