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freebsd-skq/sys/dev/vn/vn.c

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/*
* 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 1.13 94/04/02
*
* from: @(#)vn.c 8.6 (Berkeley) 4/1/94
* $FreeBSD$
*/
/*
* 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"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/conf.h>
#include <sys/disklabel.h>
#include <sys/diskslice.h>
#include <sys/stat.h>
#include <sys/conf.h>
#include <sys/module.h>
#include <sys/vnioctl.h>
#include <vm/vm.h>
#include <vm/vm_prot.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_pageout.h>
#include <vm/swap_pager.h>
#include <vm/vm_extern.h>
#include <vm/vm_zone.h>
static d_ioctl_t vnioctl;
static d_open_t vnopen;
static d_close_t vnclose;
static d_psize_t vnsize;
static d_strategy_t vnstrategy;
#define CDEV_MAJOR 43
#define BDEV_MAJOR 15
/*
* cdevsw
* D_DISK we want to look like a disk
* ( D_NOCLUSTERRW removed - clustering should be ok )
* D_CANFREE We support B_FREEBUF
*/
static struct cdevsw vn_cdevsw = {
/* open */ vnopen,
/* close */ vnclose,
/* read */ physread,
/* write */ physwrite,
/* ioctl */ vnioctl,
/* stop */ nostop,
/* reset */ noreset,
/* devtotty */ nodevtotty,
/* poll */ nopoll,
/* mmap */ nommap,
/* strategy */ vnstrategy,
/* name */ "vn",
/* parms */ noparms,
/* maj */ CDEV_MAJOR,
/* dump */ nodump,
/* psize */ vnsize,
/* flags */ D_DISK|D_CANFREE,
/* maxio */ 0,
/* bmaj */ BDEV_MAJOR
};
#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_unit;
int sc_flags; /* flags */
int sc_size; /* size of vn, sc_secsize scale */
int sc_secsize; /* sector size */
struct diskslices *sc_slices;
struct vnode *sc_vp; /* vnode if not NULL */
vm_object_t sc_object; /* backing object if not NULL */
struct ucred *sc_cred; /* credentials */
int sc_maxactive; /* max # of active requests */
struct buf sc_tab; /* transfer queue */
u_long sc_options; /* options */
SLIST_ENTRY(vn_softc) sc_list;
};
static SLIST_HEAD(, vn_softc) vn_list;
/* sc_flags */
#define VNF_INITED 0x01
#define VNF_READONLY 0x02
static u_long vn_options;
#define IFOPT(vn,opt) if (((vn)->sc_options|vn_options) & (opt))
static int vnsetcred (struct vn_softc *vn, struct ucred *cred);
static void vnclear (struct vn_softc *vn);
static int vn_modevent (module_t, int, void *);
static int vniocattach_file (struct vn_softc *, struct vn_ioctl *, dev_t dev, int flag, struct proc *p);
static int vniocattach_swap (struct vn_softc *, struct vn_ioctl *, dev_t dev, int flag, struct proc *p);
static int
vnclose(dev_t dev, int flags, int mode, struct proc *p)
{
struct vn_softc *vn = dev->si_drv1;
IFOPT(vn, VN_LABELS)
if (vn->sc_slices != NULL)
dsclose(dev, mode, vn->sc_slices);
return (0);
}
static struct vn_softc *
vnfindvn(dev_t dev)
{
int unit;
struct vn_softc *vn;
unit = dkunit(dev);
vn = dev->si_drv1;
if (!vn) {
SLIST_FOREACH(vn, &vn_list, sc_list) {
if (vn->sc_unit == unit) {
dev->si_drv1 = vn;
break;
}
}
}
if (!vn) {
vn = malloc(sizeof *vn, M_DEVBUF, M_WAITOK);
if (!vn)
return (NULL);
bzero(vn, sizeof *vn);
vn->sc_unit = unit;
dev->si_drv1 = vn;
make_dev(&vn_cdevsw, 0,
UID_ROOT, GID_OPERATOR, 0640, "vn%d", unit);
SLIST_INSERT_HEAD(&vn_list, vn, sc_list);
}
return (vn);
}
static int
vnopen(dev_t dev, int flags, int mode, struct proc *p)
{
int unit;
struct vn_softc *vn;
unit = dkunit(dev);
vn = dev->si_drv1;
if (!vn)
vn = vnfindvn(dev);
if (flags & FWRITE && vn->sc_flags & VNF_READONLY)
return (EACCES);
IFOPT(vn, VN_FOLLOW)
printf("vnopen(%s, 0x%x, 0x%x, %p)\n",
devtoname(dev), flags, mode, (void *)p);
IFOPT(vn, VN_LABELS) {
if (vn->sc_flags & VNF_INITED) {
struct disklabel label;
/* Build label for whole disk. */
bzero(&label, sizeof label);
label.d_secsize = vn->sc_secsize;
label.d_nsectors = 32;
label.d_ntracks = 64 / (vn->sc_secsize / DEV_BSIZE);
label.d_secpercyl = label.d_nsectors * label.d_ntracks;
label.d_ncylinders = vn->sc_size / label.d_secpercyl;
label.d_secperunit = vn->sc_size;
label.d_partitions[RAW_PART].p_size = vn->sc_size;
return (dsopen("vn", dev, mode, 0, &vn->sc_slices,
&label));
}
if (dkslice(dev) != WHOLE_DISK_SLICE ||
dkpart(dev) != RAW_PART ||
mode != S_IFCHR)
return (ENXIO);
}
return(0);
}
/*
* vnstrategy:
*
* Run strategy routine for VN device. We use VOP_READ/VOP_WRITE calls
* for vnode-backed vn's, and the new vm_pager_strategy() call for
* vm_object-backed vn's.
*
* Currently B_ASYNC is only partially handled - for OBJT_SWAP I/O only.
*
* NOTE: bp->b_blkno is DEV_BSIZE'd. We must generate bp->b_pblkno for
* our uio or vn_pager_strategy() call that is vn->sc_secsize'd
*/
static void
vnstrategy(struct buf *bp)
{
int unit;
struct vn_softc *vn;
int error;
int isvplocked = 0;
long sz;
struct uio auio;
struct iovec aiov;
unit = dkunit(bp->b_dev);
vn = bp->b_dev->si_drv1;
if (!vn)
vn = vnfindvn(bp->b_dev);
IFOPT(vn, VN_DEBUG)
printf("vnstrategy(%p): unit %d\n", bp, unit);
if ((vn->sc_flags & VNF_INITED) == 0) {
bp->b_error = ENXIO;
bp->b_flags |= B_ERROR;
biodone(bp);
return;
}
bp->b_resid = bp->b_bcount;
IFOPT(vn, VN_LABELS) {
if (vn->sc_slices != NULL && dscheck(bp, vn->sc_slices) <= 0) {
bp->b_flags |= B_INVAL;
biodone(bp);
return;
}
} else {
int pbn;
pbn = bp->b_blkno * (vn->sc_secsize / DEV_BSIZE);
sz = howmany(bp->b_bcount, vn->sc_secsize);
if (pbn < 0 || pbn + sz > vn->sc_size) {
if (pbn != vn->sc_size) {
bp->b_error = EINVAL;
bp->b_flags |= B_ERROR | B_INVAL;
}
biodone(bp);
return;
}
bp->b_pblkno = pbn;
}
if (vn->sc_vp && (bp->b_flags & B_FREEBUF)) {
/*
* Not handled for vnode-backed element yet.
*/
biodone(bp);
} else if (vn->sc_vp) {
/*
* VNODE I/O
*/
aiov.iov_base = bp->b_data;
aiov.iov_len = bp->b_bcount;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = (vm_ooffset_t)bp->b_pblkno * vn->sc_secsize;
auio.uio_segflg = UIO_SYSSPACE;
if( bp->b_flags & B_READ)
auio.uio_rw = UIO_READ;
else
auio.uio_rw = UIO_WRITE;
auio.uio_resid = bp->b_bcount;
auio.uio_procp = curproc;
if (!VOP_ISLOCKED(vn->sc_vp)) {
isvplocked = 1;
vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY, curproc);
}
if( bp->b_flags & B_READ)
error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
else
error = VOP_WRITE(vn->sc_vp, &auio, 0, vn->sc_cred);
if (isvplocked) {
VOP_UNLOCK(vn->sc_vp, 0, curproc);
isvplocked = 0;
}
bp->b_resid = auio.uio_resid;
if( error ) {
bp->b_error = error;
bp->b_flags |= B_ERROR;
}
biodone(bp);
} else if (vn->sc_object) {
/*
* OBJT_SWAP I/O
*
* ( handles read, write, freebuf )
*/
vm_pager_strategy(vn->sc_object, bp);
} else {
bp->b_flags |= B_ERROR;
bp->b_error = EINVAL;
biodone(bp);
}
}
/* ARGSUSED */
static int
vnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
struct vn_softc *vn;
struct vn_ioctl *vio;
int error;
u_long *f;
vn = dev->si_drv1;
IFOPT(vn,VN_FOLLOW)
printf("vnioctl(%s, 0x%lx, %p, 0x%x, %p): unit %d\n",
devtoname(dev), cmd, (void *)data, flag, (void *)p,
dkunit(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);
if (error != ENOIOCTL)
return (error);
}
if (dkslice(dev) != WHOLE_DISK_SLICE ||
dkpart(dev) != RAW_PART)
return (ENOTTY);
}
vn_specific:
error = suser(p);
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);
if (vio->vn_file == NULL)
error = vniocattach_swap(vn, vio, dev, flag, p);
else
error = vniocattach_file(vn, vio, dev, flag, p);
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? (Hint: They are not)
*/
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:
error = ENOTTY;
break;
}
return(error);
}
/*
* vniocattach_file:
*
* Attach a file to a VN partition. Return the size in the vn_size
* field.
*/
static int
vniocattach_file(vn, vio, dev, flag, p)
struct vn_softc *vn;
struct vn_ioctl *vio;
dev_t dev;
int flag;
struct proc *p;
{
struct vattr vattr;
struct nameidata nd;
int error, flags;
flags = FREAD|FWRITE;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vn_file, p);
error = vn_open(&nd, flags, 0);
if (error) {
if (error != EACCES && error != EPERM && error != EROFS)
return (error);
flags &= ~FWRITE;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vn_file, p);
error = vn_open(&nd, flags, 0);
if (error)
return (error);
}
if (nd.ni_vp->v_type != VREG ||
(error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p))) {
VOP_UNLOCK(nd.ni_vp, 0, p);
(void) vn_close(nd.ni_vp, flags, p->p_ucred, p);
return (error ? error : EINVAL);
}
VOP_UNLOCK(nd.ni_vp, 0, p);
vn->sc_secsize = DEV_BSIZE;
vn->sc_vp = nd.ni_vp;
vn->sc_size = vattr.va_size / vn->sc_secsize; /* note truncation */
error = vnsetcred(vn, p->p_ucred);
if (error) {
(void) vn_close(nd.ni_vp, flags, p->p_ucred, p);
return(error);
}
if (dev->si_bsize_phys < vn->sc_secsize)
dev->si_bsize_phys = vn->sc_secsize;
if (dev->si_bsize_best < vn->sc_secsize)
dev->si_bsize_best = vn->sc_secsize;
vn->sc_flags |= VNF_INITED;
if (flags == FREAD)
vn->sc_flags |= VNF_READONLY;
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 blks\n",
vn->sc_vp, vn->sc_size);
return(0);
}
/*
* vniocattach_swap:
*
* Attach swap backing store to a VN partition of the size specified
* in vn_size.
*/
static int
vniocattach_swap(vn, vio, dev, flag, p)
struct vn_softc *vn;
struct vn_ioctl *vio;
dev_t dev;
int flag;
struct proc *p;
{
int error;
/*
* Range check. Disallow negative sizes or any size less then the
* size of a page. Then round to a page.
*/
if (vio->vn_size <= 0)
return(EDOM);
/*
* Allocate an OBJT_SWAP object.
*
* sc_secsize is PAGE_SIZE'd
*
* vio->vn_size is in PAGE_SIZE'd chunks.
* sc_size must be in PAGE_SIZE'd chunks.
* Note the truncation.
*/
vn->sc_secsize = PAGE_SIZE;
vn->sc_size = vio->vn_size;
vn->sc_object =
vm_pager_allocate(OBJT_SWAP, NULL, vn->sc_secsize * (vm_ooffset_t)vio->vn_size, VM_PROT_DEFAULT, 0);
vn->sc_flags |= VNF_INITED;
error = vnsetcred(vn, p->p_ucred);
if (error == 0) {
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 == 0) {
IFOPT(vn, VN_FOLLOW) {
printf("vnioctl: SET vp %p size %x\n",
vn->sc_vp, vn->sc_size);
}
}
if (error)
vnclear(vn);
return(error);
}
/*
* 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 = 0;
/*
* Set credits in our softc
*/
if (vn->sc_cred)
crfree(vn->sc_cred);
vn->sc_cred = crdup(cred);
/*
* Horrible kludge to establish credentials for NFS XXX.
*/
if (vn->sc_vp) {
tmpbuf = malloc(vn->sc_secsize, M_TEMP, M_WAITOK);
aiov.iov_base = tmpbuf;
aiov.iov_len = vn->sc_secsize;
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
vnclear(struct vn_softc *vn)
{
struct proc *p = curproc; /* XXX */
IFOPT(vn, VN_FOLLOW)
printf("vnclear(%p): vp=%p\n", vn, vn->sc_vp);
if (vn->sc_slices != NULL)
dsgone(&vn->sc_slices);
vn->sc_flags &= ~VNF_INITED;
if (vn->sc_vp != NULL) {
(void)vn_close(vn->sc_vp, vn->sc_flags & VNF_READONLY ?
FREAD : (FREAD|FWRITE), vn->sc_cred, p);
vn->sc_vp = NULL;
}
vn->sc_flags &= ~VNF_READONLY;
if (vn->sc_cred) {
crfree(vn->sc_cred);
vn->sc_cred = NULL;
}
if (vn->sc_object != NULL) {
vm_pager_deallocate(vn->sc_object);
vn->sc_object = NULL;
}
vn->sc_size = 0;
}
static int
vnsize(dev_t dev)
{
struct vn_softc *vn;
vn = dev->si_drv1;
if (!vn)
return(-1);
if ((vn->sc_flags & VNF_INITED) == 0)
return(-1);
return(vn->sc_size);
}
static int
vn_modevent(module_t mod, int type, void *data)
{
struct vn_softc *vn;
switch (type) {
case MOD_LOAD:
break;
case MOD_UNLOAD:
/* fall through */
case MOD_SHUTDOWN:
for (;;) {
vn = SLIST_FIRST(&vn_list);
if (!vn)
break;
SLIST_REMOVE_HEAD(&vn_list, sc_list);
if (vn->sc_flags & VNF_INITED)
vnclear(vn);
free(vn, M_DEVBUF);
}
break;
default:
break;
}
return 0;
}
DEV_MODULE(vn, CDEV_MAJOR, BDEV_MAJOR, vn_cdevsw, vn_modevent, 0);
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