4.4BSD/usr/src/sys/dev/vn.c
/*
* Copyright (c) 1988 University of Utah.
* Copyright (c) 1990, 1993
* 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 $Hdr: vn.c 1.8 92/12/20$
*
* @(#)vn.c 8.1 (Berkeley) 6/10/93
*/
/*
* 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).
*
* NOTE 3: Doesn't interact with leases, should it?
*/
#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/file.h>
#include <sys/uio.h>
#include <miscfs/specfs/specdev.h>
#include <dev/vnioctl.h>
#ifdef DEBUG
int vndebug = 0x00;
#define VDB_FOLLOW 0x01
#define VDB_INIT 0x02
#define VDB_IO 0x04
#endif
#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 */
struct buf sc_tab; /* transfer queue */
};
/* sc_flags */
#define VNF_ALIVE 0x01
#define VNF_INITED 0x02
#if 0 /* if you need static allocation */
struct vn_softc vn_softc[NVN];
int numvnd = NVN;
#else
struct vn_softc *vn_softc;
int numvnd;
#endif
void
vnattach(num)
int num;
{
char *mem;
register u_long size;
if (num <= 0)
return;
size = num * sizeof(struct vn_softc);
mem = malloc(size, M_DEVBUF, M_NOWAIT);
if (mem == NULL) {
printf("WARNING: no memory for vnode disks\n");
return;
}
bzero(mem, size);
vn_softc = (struct vn_softc *)mem;
numvnd = num;
}
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 >= numvnd)
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 void 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_iosize;
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, NULL);
#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 */
nbp->b_rcred = vn->sc_cred; /* XXX crdup? */
nbp->b_wcred = vn->sc_cred; /* XXX crdup? */
nbp->b_dirtyoff = bp->b_dirtyoff;
nbp->b_dirtyend = bp->b_dirtyend;
nbp->b_validoff = bp->b_validoff;
nbp->b_validend = bp->b_validend;
/*
* Just sort by block number
*/
nbp->b_cylin = nbp->b_blkno;
s = splbio();
disksort(&vn->sc_tab, nbp);
if (vn->sc_tab.b_active < vn->sc_maxactive) {
vn->sc_tab.b_active++;
vnstart(vn);
}
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(vn)
register struct vn_softc *vn;
{
register struct buf *bp;
/*
* Dequeue now since lower level strategy routine might
* queue using same links
*/
bp = vn->sc_tab.b_actf;
vn->sc_tab.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",
vn-vn_softc, bp, bp->b_vp, bp->b_blkno, bp->b_un.b_addr,
bp->b_bcount);
#endif
if ((bp->b_flags & B_READ) == 0)
bp->b_vp->v_numoutput++;
VOP_STRATEGY(bp);
}
void
vniodone(bp)
register struct buf *bp;
{
register struct buf *pbp = (struct buf *)bp->b_pfcent; /* XXX */
register struct vn_softc *vn = &vn_softc[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",
vn-vn_softc, 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 (vn->sc_tab.b_actf)
vnstart(vn);
else
vn->sc_tab.b_active--;
splx(s);
}
vnread(dev, uio, flags, p)
dev_t dev;
struct uio *uio;
int flags;
struct proc *p;
{
#ifdef DEBUG
if (vndebug & VDB_FOLLOW)
printf("vnread(%x, %x, %x, %x)\n", dev, uio, flags, p);
#endif
return(physio(vnstrategy, NULL, dev, B_READ, minphys, uio));
}
vnwrite(dev, uio, flags, p)
dev_t dev;
struct uio *uio;
int flags;
struct proc *p;
{
#ifdef DEBUG
if (vndebug & VDB_FOLLOW)
printf("vnwrite(%x, %x, %x, %x)\n", dev, uio, flags, p);
#endif
return(physio(vnstrategy, NULL, 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 >= numvnd)
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.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vn_file, p);
if (error = vn_open(&nd, 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 int (**nfsv2_vnodeop_p)();
if (vp->v_op == nfsv2_vnodeop_p)
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[numvnd]; 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 >= numvnd || (vn->sc_flags & VNF_INITED) == 0)
return(-1);
return(vn->sc_size);
}
vndump(dev)
{
return(ENXIO);
}
#endif