u_arg is gone

[unix-history] / usr / src / sys / 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.
*
* %sccs.include.redist.c%
*
* from: Utah $Hdr: fd.c 1.3 89/12/03$
*
*      @(#)vn.c        7.1 (Berkeley) %G%
*/

/*
* File (vnode) disk driver.
*
* Block/character interface to a vnode.  Note that 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: 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 "fd.h"
#if NFD > 0

#include "param.h"
#include "systm.h"
#include "buf.h"
#include "errno.h"
#include "dkstat.h"
#include "ioctl.h"
#include "user.h"
#include "vfs.h"
#include "vnode.h"
#include "file.h"
#include "uio.h"
#include "malloc.h"

#include "fdioctl.h"

#ifdef DEBUG
int fddebug = 0x00;
#define FDB_FOLLOW      0x01
#define FDB_INIT        0x02
#define FDB_IO          0x04
#endif

struct  buf fdbuf[NFD];
struct  buf fdtab[NFD];

#define b_cylin b_resid

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

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

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

/* sc_flags */
#define FDF_ALIVE       0x01
#define FDF_INITED      0x02

fdopen(dev, flags)
       dev_t dev;
{
       int unit = fdunit(dev);

#ifdef DEBUG
       if (fddebug & FDB_FOLLOW)
               printf("fdopen(%x, %x)\n", dev, flags);
#endif
       if (unit >= NFD)
               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.
*/
fdstrategy(bp)
       register struct buf *bp;
{
       int unit = fdunit(bp->b_dev);
       register struct fd_softc *fs = &fd_softc[unit];
       register struct buf *nbp;
       register int bn, bsize, resid;
       register caddr_t addr;
       int sz, flags;
       extern int fdiodone();

#ifdef DEBUG
       if (fddebug & FDB_FOLLOW)
               printf("fdstrategy(%x): unit %d\n", bp, unit);
#endif
       if ((fs->sc_flags & FDF_INITED) == 0) {
               bp->b_error = ENXIO;
               bp->b_flags |= B_ERROR;
               iodone(bp);
               return;
       }
       bn = bp->b_blkno;
       sz = howmany(bp->b_bcount, DEV_BSIZE);
       bp->b_resid = bp->b_bcount;
       if (bn < 0 || bn + sz > fs->sc_size) {
               if (bn != fs->sc_size) {
                       bp->b_error = EINVAL;
                       bp->b_flags |= B_ERROR;
               }
               iodone(bp);
               return;
       }
       bn = dbtob(bn);
       bsize = fs->sc_vp->v_vfsp->vfs_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 = getfdbuf();
               off = bn % bsize;
               sz = MIN(bsize - off, resid);
               (void) VOP_BMAP(fs->sc_vp, bn / bsize, &vp, &nbn);
#ifdef DEBUG
               if (fddebug & FDB_IO)
                       printf("fdstrategy: vp %x/%x bn %x/%x dev %x\n",
                              fs->sc_vp, vp, bn, nbn, vp->v_rdev);
#endif
               nbp->b_flags = flags;
               nbp->b_bcount = sz;
               nbp->b_bufsize = bp->b_bufsize;
               nbp->b_error = 0;
               nbp->b_dev = vp->v_rdev;
               nbp->b_un.b_addr = addr;
               nbp->b_blkno = nbn + btodb(off);
               nbp->b_proc = bp->b_proc;
               nbp->b_iodone = fdiodone;
               nbp->b_vp = vp;
               nbp->b_pfcent = (int) bp;       /* XXX */
               /*
                * Just sort by block number
                */
               nbp->b_cylin = nbp->b_blkno;
               s = splbio();
               disksort(&fdtab[unit], nbp);
               if (fdtab[unit].b_active < fs->sc_maxactive) {
                       fdtab[unit].b_active++;
                       fdstart(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.
*/
fdstart(unit)
{
       register struct fd_softc *fs = &fd_softc[unit];
       register struct buf *bp;

       /*
        * Dequeue now since lower level strategy routine might
        * queue using same links
        */
       bp = fdtab[unit].b_actf;
       fdtab[unit].b_actf = bp->b_actf;
#ifdef DEBUG
       if (fddebug & FDB_IO)
               printf("fdstart(%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);
}

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

       s = splbio();
#ifdef DEBUG
       if (fddebug & FDB_IO)
               printf("fdiodone(%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 (fddebug & FDB_IO)
                       printf("fdiodone: bp %x error %d\n", bp, bp->b_error);
#endif
               pbp->b_flags |= B_ERROR;
               pbp->b_error = geterror(bp);
       }
       pbp->b_resid -= bp->b_bcount;
       putfdbuf(bp);
       if (pbp->b_resid == 0) {
#ifdef DEBUG
               if (fddebug & FDB_IO)
                       printf("fdiodone: pbp %x iodone\n", pbp);
#endif
               iodone(pbp);
       }
       if (fdtab[unit].b_actf)
               fdstart(unit);
       else
               fdtab[unit].b_active--;
       splx(s);
}

fdread(dev, uio)
       dev_t dev;
       struct uio *uio;
{
       register int unit = fdunit(dev);

#ifdef DEBUG
       if (fddebug & FDB_FOLLOW)
               printf("fdread(%x, %x)\n", dev, uio);
#endif
       return(physio(fdstrategy, &fdbuf[unit], dev, B_READ, minphys, uio));
}

fdwrite(dev, uio)
       dev_t dev;
       struct uio *uio;
{
       register int unit = fdunit(dev);

#ifdef DEBUG
       if (fddebug & FDB_FOLLOW)
               printf("fdwrite(%x, %x)\n", dev, uio);
#endif
       return(physio(fdstrategy, &fdbuf[unit], dev, B_WRITE, minphys, uio));
}

/* ARGSUSED */
fdioctl(dev, cmd, data, flag)
       dev_t dev;
       u_long cmd;
       caddr_t data;
       int flag;
{
       int unit = fdunit(dev);
       register struct fd_softc *fs;
       struct fd_ioctl *fio;
       struct vattr vattr;
       struct vnode *vp;
       int error;

#ifdef DEBUG
       if (fddebug & FDB_FOLLOW)
               printf("fdioctl(%x, %x, %x, %x): unit %d\n",
                      dev, cmd, data, flag, unit);
#endif
       error = suser(u.u_cred, &u.u_acflag);
       if (error)
               return (error);
       if (unit >= NFD)
               return (ENXIO);

       fs = &fd_softc[unit];
       fio = (struct fd_ioctl *)data;
       switch (cmd) {

       case FDIOCSET:
               if (fs->sc_flags & FDF_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.
                */
               error = vn_open(fio->fd_file, UIO_USERSPACE,
                               FREAD|FWRITE, 0, &vp);
               if (error)
                       return(error);
               error = VOP_GETATTR(vp, &vattr, u.u_cred);
               if (error) {
                       vn_close(vp, FREAD|FWRITE);
                       VN_RELE(vp);
                       return(error);
               }
               fs->sc_vp = vp;
               fs->sc_size = btodb(vattr.va_size);     /* note truncation */
               error = fdsetcred(fs);
               if (error) {
                       vn_close(vp, FREAD|FWRITE);
                       VN_RELE(vp);
                       return(error);
               }
               fdthrottle(fs, vp);
               fio->fd_size = dbtob(fs->sc_size);
               fs->sc_flags |= FDF_INITED;
#ifdef DEBUG
               if (fddebug & FDB_INIT)
                       printf("fdioctl: SET vp %x size %x\n",
                              fs->sc_vp, fs->sc_size);
#endif
               break;

       case FDIOCCLR:
               if ((fs->sc_flags & FDF_INITED) == 0)
                       return(ENXIO);
               fdclear(fs);
#ifdef DEBUG
               if (fddebug & FDB_INIT)
                       printf("fdioctl: 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).
*/
fdsetcred(fs)
       register struct fd_softc *fs;
{
       struct uio auio;
       struct iovec aiov;
       char tmpbuf[DEV_BSIZE];

       fs->sc_cred = crdup(u.u_cred);
       /* XXX: Horrible kludge to establish credentials for NFS */
       aiov.iov_base = tmpbuf;
       aiov.iov_len = MIN(DEV_BSIZE, dbtob(fs->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(fs->sc_vp, &auio, 0, fs->sc_cred));
}

/*
* Set maxactive based on FS type
*/
fdthrottle(fs, vp)
       register struct fd_softc *fs;
       struct vnode *vp;
{
       extern struct vnodeops ufs_vnodeops, nfs_vnodeops;

       if (vp->v_op == &nfs_vnodeops)
               fs->sc_maxactive = 2;
       else
               fs->sc_maxactive = 8;

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

fdshutdown()
{
       register struct fd_softc *fs;

       for (fs = &fd_softc[0]; fs < &fd_softc[NFD]; fs++)
               if (fs->sc_flags & FDF_INITED)
                       fdclear(fs);
}

fdclear(fs)
       register struct fd_softc *fs;
{
       register struct vnode *vp = fs->sc_vp;

#ifdef DEBUG
       if (fddebug & FDB_FOLLOW)
               printf("fdclear(%x): vp %x\n", vp);
#endif
       fs->sc_flags &= ~FDF_INITED;
       if (vp == (struct vnode *)0)
               panic("fdioctl: null vp");
#if 0
       /* XXX - this doesn't work right now */
       (void) VOP_FSYNC(vp, fs->sc_cred);
#endif
       vn_close(vp, FREAD|FWRITE);
       VN_RELE(vp);
       crfree(fs->sc_cred);
       fs->sc_vp = (struct vnode *)0;
       fs->sc_cred = (struct ucred *)0;
       fs->sc_size = 0;
}

fdsize(dev)
       dev_t dev;
{
       int unit = fdunit(dev);
       register struct fd_softc *fs = &fd_softc[unit];

       if (unit >= NFD || (fs->sc_flags & FDF_INITED) == 0)
               return(-1);
       return(fs->sc_size);
}

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