vn.c

来自「基于组件方式开发操作系统的OSKIT源代码」· C语言 代码 · 共 686 行 · 第 1/2 页

			off = byten % bsize;
			if (off)
				sz = bsize - off;
			else
				sz = (1 + nra) * bsize;
			if (resid < sz)
				sz = resid;

			if (error) {
				bp->b_resid -= (resid - sz);
				bp->b_flags |= B_ERROR;
				biodone(bp);
				putvnbuf(nbp);
				return;
			}

			IFOPT(vn,VN_IO)
				printf(
			/* XXX no %qx in kernel.  Synthesize it. */
			"vnstrategy: vp %p/%p bn 0x%lx%08lx/0x%lx sz 0x%lx\n",
				   (void *)vn->sc_vp, (void *)vp,
				   (u_long)(byten >> 32), (u_long)byten,
				   (u_long)nbn, sz);

			nbp->b_flags = flags;
			nbp->b_bcount = sz;
			nbp->b_bufsize = sz;
			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_data = addr;
			nbp->b_blkno = nbn + btodb(off);
			nbp->b_offset = dbtob(nbn) + off;
			nbp->b_proc = bp->b_proc;
			nbp->b_iodone = vniodone;
			nbp->b_vp = vp;
			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;

			if ((nbp->b_flags & B_READ) == 0)
				nbp->b_vp->v_numoutput++;

			VOP_STRATEGY(vp, nbp);

			s = splbio();
			while ((nbp->b_flags & B_DONE) == 0) {
				nbp->b_flags |= B_WANTED;
				tsleep(nbp, PRIBIO, "vnwait", 0);
			}
			splx(s);

			if( nbp->b_flags & B_ERROR) {
				bp->b_flags |= B_ERROR;
				bp->b_resid -= (resid - sz);
				biodone(bp);
				putvnbuf(nbp);
				return;
			}

			byten += sz;
			addr += sz;
			resid -= sz;
		}
		bp->b_resid = resid;
		biodone(bp);
		putvnbuf(nbp);
	}
}


void
vniodone( struct buf *bp) {
	bp->b_flags |= B_DONE;
	wakeup((caddr_t) bp);
}

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

	IFOPT(vn,VN_FOLLOW)
		printf("vnioctl(0x%lx, 0x%lx, %p, 0x%x, %p): unit %d\n",
		   (u_long)dev, cmd, (void *)data, flag, (void *)p,
		   vnunit(dev));

	switch (cmd) {
	case VNIOCATTACH:
	case VNIOCDETACH:
	case VNIOCGSET:
	case VNIOCGCLEAR:
	case VNIOCUSET:
	case VNIOCUCLEAR:
		goto vn_specific;
	}

	IFOPT(vn,VN_LABELS) {
		if (vn->sc_slices != NULL) {
			error = dsioctl("vn", dev, cmd, data, flag,
					&vn->sc_slices, vnstrategy,
					(ds_setgeom_t *)NULL);
			if (error != ENOIOCTL)
				return (error);
		}
		if (dkslice(dev) != WHOLE_DISK_SLICE ||
		    dkpart(dev) != RAW_PART)
			return (ENOTTY);
	}

    vn_specific:

	error = suser(p->p_ucred, &p->p_acflag);
	if (error)
		return (error);

	vio = (struct vn_ioctl *)data;
	f = (u_long*)data;
	switch (cmd) {

	case VNIOCATTACH:
		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);
		error = vn_open(&nd, FREAD|FWRITE, 0);
		if (error)
			return(error);
		error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p);
		if (error) {
			VOP_UNLOCK(nd.ni_vp, 0, p);
			(void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
			return(error);
		}
		VOP_UNLOCK(nd.ni_vp, 0, p);
		vn->sc_vp = nd.ni_vp;
		vn->sc_size = btodb(vattr.va_size);	/* note truncation */
		error = vnsetcred(vn, p->p_ucred);
		if (error) {
			(void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
			return(error);
		}
		vio->vn_size = dbtob(vn->sc_size);
		vn->sc_flags |= VNF_INITED;
		IFOPT(vn, VN_LABELS) {
			/*
			 * Reopen so that `ds' knows which devices are open.
			 * If this is the first VNIOCSET, then we've
			 * guaranteed that the device is the cdev and that
			 * no other slices or labels are open.  Otherwise,
			 * we rely on VNIOCCLR not being abused.
			 */
			error = vnopen(dev, flag, S_IFCHR, p);
			if (error)
				vnclear(vn);
		}
		IFOPT(vn, VN_FOLLOW)
			printf("vnioctl: SET vp %p size %x\n",
			       vn->sc_vp, vn->sc_size);
		break;

	case VNIOCDETACH:
		if ((vn->sc_flags & VNF_INITED) == 0)
			return(ENXIO);
		/*
		 * XXX handle i/o in progress.  Return EBUSY, or wait, or
		 * flush the i/o.
		 * XXX handle multiple opens of the device.  Return EBUSY,
		 * or revoke the fd's.
		 * How are these problems handled for removable and failing
		 * hardware devices?
		 */
		vnclear(vn);
		IFOPT(vn, VN_FOLLOW)
			printf("vnioctl: CLRed\n");
		break;

	case VNIOCGSET:
		vn_options |= *f;
		*f = vn_options;
		break;

	case VNIOCGCLEAR:
		vn_options &= ~(*f);
		*f = vn_options;
		break;

	case VNIOCUSET:
		vn->sc_options |= *f;
		*f = vn->sc_options;
		break;

	case VNIOCUCLEAR:
		vn->sc_options &= ~(*f);
		*f = vn->sc_options;
		break;

	default:
		return (ENOTTY);
	}
	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).
 */
int
vnsetcred(struct vn_softc *vn, struct ucred *cred)
{
	struct uio auio;
	struct iovec aiov;
	char *tmpbuf;
	int error;

	vn->sc_cred = crdup(cred);
	tmpbuf = malloc(DEV_BSIZE, M_TEMP, M_WAITOK);

	/* 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;
	vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY, curproc);
	error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
	VOP_UNLOCK(vn->sc_vp, 0, curproc);

	free(tmpbuf, M_TEMP);
	return (error);
}

void
vnshutdown(int howto, void *ignored)
{
	int i;

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

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

	IFOPT(vn, VN_FOLLOW)
		printf("vnclear(%p): vp=%p\n", vn, vp);
	if (vn->sc_slices != NULL)
		dsgone(&vn->sc_slices);
	vn->sc_flags &= ~VNF_INITED;
	if (vp == (struct vnode *)0)
		panic("vnclear: null vp");
	(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;
}

static	int
vnsize(dev_t dev)
{
	int unit = vnunit(dev);

	if (unit >= NVN || (!vn_softc[unit]) ||
	    (vn_softc[unit]->sc_flags & VNF_INITED) == 0)
		return(-1);
	return(vn_softc[unit]->sc_size);
}

static	int
vndump(dev_t dev)
{
	return (ENODEV);
}

static vn_devsw_installed = 0;

static void 
vn_drvinit(void *unused)
{
#ifdef DEVFS
	int unit;
#endif
	if(!vn_devsw_installed ) {
		if (at_shutdown(&vnshutdown, NULL, SHUTDOWN_POST_SYNC)) {
			printf("vn: could not install shutdown hook\n");
			return;
		}
		cdevsw_add_generic(BDEV_MAJOR, CDEV_MAJOR, &vn_cdevsw);
		vn_devsw_installed = 1;
	}
#ifdef DEVFS
	for (unit = 0; unit < NVN; unit++) {
		struct vn_softc *vn;

		vn = malloc(sizeof *vn, M_DEVBUF, M_NOWAIT);
		if (!vn)
			return;
		bzero(vn, sizeof *vn);
		vn_softc[unit] = vn;
		vn->r_devfs_token = devfs_add_devswf(&vn_cdevsw, 
						     dkmakeminor(unit, 0, 0),
                                 		     DV_CHR, UID_ROOT, 
						     GID_OPERATOR, 0640,
                                 		     "rvn%d", unit);
        	vn->devfs_token = devfs_add_devswf(&vn_cdevsw,
						   dkmakeminor(unit, 0, 0),
                                 		   DV_BLK, UID_ROOT, 
						   GID_OPERATOR, 0640,
                                 		   "vn%d", unit);
	}
#endif
}

SYSINIT(vndev, SI_SUB_DRIVERS, SI_ORDER_ANY, vn_drvinit, NULL)

#endif