usr/src/sys/hp300/dev/vn.c

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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.
 *
 * from: Utah $Hdr: vn.c 1.1 91/04/30$
 *
 *      @(#)vn.c        7.6 (Berkeley) 6/21/91
 */

/*
 * Vnode disk driver.
 *
 * Block/character interface to a vnode.  Allows one to treat a file
 * as a disk (e.g. build a filesystem in it, mount it, etc.).
 *
 * NOTE 1: This uses the VOP_BMAP/VOP_STRATEGY interface to the vnode
 * instead of a simple VOP_RDWR.  We do this to avoid distorting the
 * local buffer cache.
 *
 * NOTE 2: There is a security issue involved with this driver.
 * Once mounted all access to the contents of the "mapped" file via
 * the special file is controlled by the permissions on the special
 * file, the protection of the mapped file is ignored (effectively,
 * by using root credentials in all transactions).
 */
#include "vn.h"
#if NVN > 0

#include "sys/param.h"
#include "sys/systm.h"
#include "sys/namei.h"
#include "sys/proc.h"
#include "sys/errno.h"
#include "sys/dkstat.h"
#include "sys/buf.h"
#include "sys/malloc.h"
#include "sys/ioctl.h"
#include "sys/mount.h"
#include "sys/vnode.h"
#include "sys/specdev.h"
#include "sys/file.h"
#include "sys/uio.h"

#include "vnioctl.h"

#ifdef DEBUG
int vndebug = 0x00;
#define VDB_FOLLOW      0x01
#define VDB_INIT        0x02
#define VDB_IO          0x04
#endif

struct  buf vnbuf[NVN];
struct  buf vntab[NVN];

#define b_cylin b_resid

#define vnunit(x)       ((minor(x) >> 3) & 0x7) /* for consistency */

#define getvnbuf()      \
        ((struct buf *)malloc(sizeof(struct buf), M_DEVBUF, M_WAITOK))
#define putvnbuf(bp)    \
        free((caddr_t)(bp), M_DEVBUF)

struct vn_softc {
        int              sc_flags;      /* flags */
        size_t           sc_size;       /* size of vn */
        struct vnode    *sc_vp;         /* vnode */
        struct ucred    *sc_cred;       /* credentials */
        int              sc_maxactive;  /* max # of active requests */
} vn_softc[NVN];

/* sc_flags */
#define VNF_ALIVE       0x01
#define VNF_INITED      0x02

int
vnopen(dev, flags, mode, p)
        dev_t dev;
        int flags, mode;
        struct proc *p;
{
        int unit = vnunit(dev);

#ifdef DEBUG
        if (vndebug & VDB_FOLLOW)
                printf("vnopen(%x, %x, %x, %x)\n", dev, flags, mode, p);
#endif
        if (unit >= NVN)
                return(ENXIO);
        return(0);
}

/*
 * Break the request into bsize pieces and submit using VOP_BMAP/VOP_STRATEGY.
 * Note that this driver can only be used for swapping over NFS on the hp
 * since nfs_strategy on the vax cannot handle u-areas and page tables.
 */
vnstrategy(bp)
        register struct buf *bp;
{
        int unit = vnunit(bp->b_dev);
        register struct vn_softc *vn = &vn_softc[unit];
        register struct buf *nbp;
        register int bn, bsize, resid;
        register caddr_t addr;
        int sz, flags;
        extern int vniodone();

#ifdef DEBUG
        if (vndebug & VDB_FOLLOW)
                printf("vnstrategy(%x): unit %d\n", bp, unit);
#endif
        if ((vn->sc_flags & VNF_INITED) == 0) {
                bp->b_error = ENXIO;
                bp->b_flags |= B_ERROR;
                biodone(bp);
                return;
        }
        bn = bp->b_blkno;
        sz = howmany(bp->b_bcount, DEV_BSIZE);
        bp->b_resid = bp->b_bcount;
        if (bn < 0 || bn + sz > vn->sc_size) {
                if (bn != vn->sc_size) {
                        bp->b_error = EINVAL;
                        bp->b_flags |= B_ERROR;
                }
                biodone(bp);
                return;
        }
        bn = dbtob(bn);
        bsize = vn->sc_vp->v_mount->mnt_stat.f_bsize;
        addr = bp->b_un.b_addr;
        flags = bp->b_flags | B_CALL;
        for (resid = bp->b_resid; resid; resid -= sz) {
                struct vnode *vp;
                daddr_t nbn;
                int off, s;

                nbp = getvnbuf();
                off = bn % bsize;
                sz = MIN(bsize - off, resid);
                (void) VOP_BMAP(vn->sc_vp, bn / bsize, &vp, &nbn);
#ifdef DEBUG
                if (vndebug & VDB_IO)
                        printf("vnstrategy: vp %x/%x bn %x/%x\n",
                               vn->sc_vp, vp, bn, nbn);
#endif
                nbp->b_flags = flags;
                nbp->b_bcount = sz;
                nbp->b_bufsize = bp->b_bufsize;
                nbp->b_error = 0;
                if (vp->v_type == VBLK || vp->v_type == VCHR)
                        nbp->b_dev = vp->v_rdev;
                else
                        nbp->b_dev = NODEV;
                nbp->b_un.b_addr = addr;
                nbp->b_blkno = nbn + btodb(off);
                nbp->b_proc = bp->b_proc;
                nbp->b_iodone = vniodone;
                nbp->b_vp = vp;
                nbp->b_pfcent = (int) bp;       /* XXX */
                /*
                 * Just sort by block number
                 */
                nbp->b_cylin = nbp->b_blkno;
                s = splbio();
                disksort(&vntab[unit], nbp);
                if (vntab[unit].b_active < vn->sc_maxactive) {
                        vntab[unit].b_active++;
                        vnstart(unit);
                }
                splx(s);
                bn += sz;
                addr += sz;
        }
}

/*
 * Feed requests sequentially.
 * We do it this way to keep from flooding NFS servers if we are connected
 * to an NFS file.  This places the burden on the client rather than the
 * server.
 */
vnstart(unit)
{
        register struct vn_softc *vn = &vn_softc[unit];
        register struct buf *bp;

        /*
         * Dequeue now since lower level strategy routine might
         * queue using same links
         */
        bp = vntab[unit].b_actf;
        vntab[unit].b_actf = bp->b_actf;
#ifdef DEBUG
        if (vndebug & VDB_IO)
                printf("vnstart(%d): bp %x vp %x blkno %x addr %x cnt %x\n",
                       unit, bp, bp->b_vp, bp->b_blkno, bp->b_un.b_addr,
                       bp->b_bcount);
#endif
        VOP_STRATEGY(bp);
}

vniodone(bp)
        register struct buf *bp;
{
        register struct buf *pbp = (struct buf *)bp->b_pfcent;  /* XXX */
        register int unit = vnunit(pbp->b_dev);
        int s;

        s = splbio();
#ifdef DEBUG
        if (vndebug & VDB_IO)
                printf("vniodone(%d): bp %x vp %x blkno %x addr %x cnt %x\n",
                       unit, bp, bp->b_vp, bp->b_blkno, bp->b_un.b_addr,
                       bp->b_bcount);
#endif
        if (bp->b_error) {
#ifdef DEBUG
                if (vndebug & VDB_IO)
                        printf("vniodone: bp %x error %d\n", bp, bp->b_error);
#endif
                pbp->b_flags |= B_ERROR;
                pbp->b_error = biowait(bp);
        }
        pbp->b_resid -= bp->b_bcount;
        putvnbuf(bp);
        if (pbp->b_resid == 0) {
#ifdef DEBUG
                if (vndebug & VDB_IO)
                        printf("vniodone: pbp %x iodone\n", pbp);
#endif
                biodone(pbp);
        }
        if (vntab[unit].b_actf)
                vnstart(unit);
        else
                vntab[unit].b_active--;
        splx(s);
}

vnread(dev, uio, flags, p)
        dev_t dev;
        struct uio *uio;
        int flags;
        struct proc *p;
{
        register int unit = vnunit(dev);

#ifdef DEBUG
        if (vndebug & VDB_FOLLOW)
                printf("vnread(%x, %x, %x, %x)\n", dev, uio, flags, p);
#endif
        return(physio(vnstrategy, &vnbuf[unit], dev, B_READ, minphys, uio));
}

vnwrite(dev, uio, flags, p)
        dev_t dev;
        struct uio *uio;
        int flags;
        struct proc *p;
{
        register int unit = vnunit(dev);

#ifdef DEBUG
        if (vndebug & VDB_FOLLOW)
                printf("vnwrite(%x, %x, %x, %x)\n", dev, uio, flags, p);
#endif
        return(physio(vnstrategy, &vnbuf[unit], dev, B_WRITE, minphys, uio));
}

/* ARGSUSED */
vnioctl(dev, cmd, data, flag, p)
        dev_t dev;
        u_long cmd;
        caddr_t data;
        int flag;
        struct proc *p;
{
        int unit = vnunit(dev);
        register struct vn_softc *vn;
        struct vn_ioctl *vio;
        struct vattr vattr;
        struct nameidata nd;
        int error;

#ifdef DEBUG
        if (vndebug & VDB_FOLLOW)
                printf("vnioctl(%x, %x, %x, %x, %x): unit %d\n",
                       dev, cmd, data, flag, p, unit);
#endif
        error = suser(p->p_ucred, &p->p_acflag);
        if (error)
                return (error);
        if (unit >= NVN)
                return (ENXIO);

        vn = &vn_softc[unit];
        vio = (struct vn_ioctl *)data;
        switch (cmd) {

        case VNIOCSET:
                if (vn->sc_flags & VNF_INITED)
                        return(EBUSY);
                /*
                 * Always open for read and write.
                 * This is probably bogus, but it lets vn_open()
                 * weed out directories, sockets, etc. so we don't
                 * have to worry about them.
                 */
                nd.ni_segflg = UIO_USERSPACE;
                nd.ni_dirp = vio->vn_file;
                if (error = vn_open(&nd, p, FREAD|FWRITE, 0))
                        return(error);
                if (error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p)) {
                        VOP_UNLOCK(nd.ni_vp);
                        (void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
                        return(error);
                }
                VOP_UNLOCK(nd.ni_vp);
                vn->sc_vp = nd.ni_vp;
                vn->sc_size = btodb(vattr.va_size);     /* note truncation */
                if (error = vnsetcred(vn, p->p_ucred)) {
                        (void) vn_close(vn->sc_vp, FREAD|FWRITE, p->p_ucred, p);
                        return(error);
                }
                vnthrottle(vn, vn->sc_vp);
                vio->vn_size = dbtob(vn->sc_size);
                vn->sc_flags |= VNF_INITED;
#ifdef DEBUG
                if (vndebug & VDB_INIT)
                        printf("vnioctl: SET vp %x size %x\n",
                               vn->sc_vp, vn->sc_size);
#endif
                break;

        case VNIOCCLR:
                if ((vn->sc_flags & VNF_INITED) == 0)
                        return(ENXIO);
                vnclear(vn);
#ifdef DEBUG
                if (vndebug & VDB_INIT)
                        printf("vnioctl: CLRed\n");
#endif
                break;

        default:
                return(ENXIO);
        }
        return(0);
}

/*
 * Duplicate the current processes' credentials.  Since we are called only
 * as the result of a SET ioctl and only root can do that, any future access
 * to this "disk" is essentially as root.  Note that credentials may change
 * if some other uid can write directly to the mapped file (NFS).
 */
vnsetcred(vn, cred)
        register struct vn_softc *vn;
        struct ucred cred;
{
        struct uio auio;
        struct iovec aiov;
        char tmpbuf[DEV_BSIZE];

        vn->sc_cred = crdup(cred);
        /* XXX: Horrible kludge to establish credentials for NFS */
        aiov.iov_base = tmpbuf;
        aiov.iov_len = MIN(DEV_BSIZE, dbtob(vn->sc_size));
        auio.uio_iov = &aiov;
        auio.uio_iovcnt = 1;
        auio.uio_offset = 0;
        auio.uio_rw = UIO_READ;
        auio.uio_segflg = UIO_SYSSPACE;
        auio.uio_resid = aiov.iov_len;
        return(VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred));
}

/*
 * Set maxactive based on FS type
 */
vnthrottle(vn, vp)
        register struct vn_softc *vn;
        struct vnode *vp;
{
        extern struct vnodeops ufs_vnodeops, nfsv2_vnodeops;

        if (vp->v_op == &nfsv2_vnodeops)
                vn->sc_maxactive = 2;
        else
                vn->sc_maxactive = 8;

        if (vn->sc_maxactive < 1)
                vn->sc_maxactive = 1;
}

vnshutdown()
{
        register struct vn_softc *vn;

        for (vn = &vn_softc[0]; vn < &vn_softc[NVN]; vn++)
                if (vn->sc_flags & VNF_INITED)
                        vnclear(vn);
}

vnclear(vn)
        register struct vn_softc *vn;
{
        register struct vnode *vp = vn->sc_vp;
        struct proc *p = curproc;               /* XXX */

#ifdef DEBUG
        if (vndebug & VDB_FOLLOW)
                printf("vnclear(%x): vp %x\n", vp);
#endif
        vn->sc_flags &= ~VNF_INITED;
        if (vp == (struct vnode *)0)
                panic("vnioctl: null vp");
#if 0
        /* XXX - this doesn't work right now */
        (void) VOP_FSYNC(vp, 0, vn->sc_cred, MNT_WAIT, p);
#endif
        (void) vn_close(vp, FREAD|FWRITE, vn->sc_cred, p);
        crfree(vn->sc_cred);
        vn->sc_vp = (struct vnode *)0;
        vn->sc_cred = (struct ucred *)0;
        vn->sc_size = 0;
}

vnsize(dev)
        dev_t dev;
{
        int unit = vnunit(dev);
        register struct vn_softc *vn = &vn_softc[unit];

        if (unit >= NVN || (vn->sc_flags & VNF_INITED) == 0)
                return(-1);
        return(vn->sc_size);
}

vndump(dev)
{
        return(ENXIO);
}
#endif