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BSD 4_4_Lite1 release
[unix-history] / usr / src / sys / miscfs / specfs / spec_vnops.c
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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.
*
* @(#)spec_vnops.c 8.6 (Berkeley) 4/9/94
*/
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/buf.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/disklabel.h>
#include <miscfs/specfs/specdev.h>
/* symbolic sleep message strings for devices */
char devopn[] = "devopn";
char devio[] = "devio";
char devwait[] = "devwait";
char devin[] = "devin";
char devout[] = "devout";
char devioc[] = "devioc";
char devcls[] = "devcls";
int (**spec_vnodeop_p)();
struct vnodeopv_entry_desc spec_vnodeop_entries[] = {
{ &vop_default_desc, vn_default_error },
{ &vop_lookup_desc, spec_lookup }, /* lookup */
{ &vop_create_desc, spec_create }, /* create */
{ &vop_mknod_desc, spec_mknod }, /* mknod */
{ &vop_open_desc, spec_open }, /* open */
{ &vop_close_desc, spec_close }, /* close */
{ &vop_access_desc, spec_access }, /* access */
{ &vop_getattr_desc, spec_getattr }, /* getattr */
{ &vop_setattr_desc, spec_setattr }, /* setattr */
{ &vop_read_desc, spec_read }, /* read */
{ &vop_write_desc, spec_write }, /* write */
{ &vop_ioctl_desc, spec_ioctl }, /* ioctl */
{ &vop_select_desc, spec_select }, /* select */
{ &vop_mmap_desc, spec_mmap }, /* mmap */
{ &vop_fsync_desc, spec_fsync }, /* fsync */
{ &vop_seek_desc, spec_seek }, /* seek */
{ &vop_remove_desc, spec_remove }, /* remove */
{ &vop_link_desc, spec_link }, /* link */
{ &vop_rename_desc, spec_rename }, /* rename */
{ &vop_mkdir_desc, spec_mkdir }, /* mkdir */
{ &vop_rmdir_desc, spec_rmdir }, /* rmdir */
{ &vop_symlink_desc, spec_symlink }, /* symlink */
{ &vop_readdir_desc, spec_readdir }, /* readdir */
{ &vop_readlink_desc, spec_readlink }, /* readlink */
{ &vop_abortop_desc, spec_abortop }, /* abortop */
{ &vop_inactive_desc, spec_inactive }, /* inactive */
{ &vop_reclaim_desc, spec_reclaim }, /* reclaim */
{ &vop_lock_desc, spec_lock }, /* lock */
{ &vop_unlock_desc, spec_unlock }, /* unlock */
{ &vop_bmap_desc, spec_bmap }, /* bmap */
{ &vop_strategy_desc, spec_strategy }, /* strategy */
{ &vop_print_desc, spec_print }, /* print */
{ &vop_islocked_desc, spec_islocked }, /* islocked */
{ &vop_pathconf_desc, spec_pathconf }, /* pathconf */
{ &vop_advlock_desc, spec_advlock }, /* advlock */
{ &vop_blkatoff_desc, spec_blkatoff }, /* blkatoff */
{ &vop_valloc_desc, spec_valloc }, /* valloc */
{ &vop_vfree_desc, spec_vfree }, /* vfree */
{ &vop_truncate_desc, spec_truncate }, /* truncate */
{ &vop_update_desc, spec_update }, /* update */
{ &vop_bwrite_desc, spec_bwrite }, /* bwrite */
{ (struct vnodeop_desc*)NULL, (int(*)())NULL }
};
struct vnodeopv_desc spec_vnodeop_opv_desc =
{ &spec_vnodeop_p, spec_vnodeop_entries };
/*
* Trivial lookup routine that always fails.
*/
int
spec_lookup(ap)
struct vop_lookup_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap;
{
*ap->a_vpp = NULL;
return (ENOTDIR);
}
/*
* Open a special file.
*/
/* ARGSUSED */
spec_open(ap)
struct vop_open_args /* {
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
struct vnode *bvp, *vp = ap->a_vp;
dev_t bdev, dev = (dev_t)vp->v_rdev;
register int maj = major(dev);
int error;
/*
* Don't allow open if fs is mounted -nodev.
*/
if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV))
return (ENXIO);
switch (vp->v_type) {
case VCHR:
if ((u_int)maj >= nchrdev)
return (ENXIO);
if (ap->a_cred != FSCRED && (ap->a_mode & FWRITE)) {
/*
* When running in very secure mode, do not allow
* opens for writing of any disk character devices.
*/
if (securelevel >= 2 && isdisk(dev, VCHR))
return (EPERM);
/*
* When running in secure mode, do not allow opens
* for writing of /dev/mem, /dev/kmem, or character
* devices whose corresponding block devices are
* currently mounted.
*/
if (securelevel >= 1) {
if ((bdev = chrtoblk(dev)) != NODEV &&
vfinddev(bdev, VBLK, &bvp) &&
bvp->v_usecount > 0 &&
(error = vfs_mountedon(bvp)))
return (error);
if (iskmemdev(dev))
return (EPERM);
}
}
VOP_UNLOCK(vp);
error = (*cdevsw[maj].d_open)(dev, ap->a_mode, S_IFCHR, ap->a_p);
VOP_LOCK(vp);
return (error);
case VBLK:
if ((u_int)maj >= nblkdev)
return (ENXIO);
/*
* When running in very secure mode, do not allow
* opens for writing of any disk block devices.
*/
if (securelevel >= 2 && ap->a_cred != FSCRED &&
(ap->a_mode & FWRITE) && isdisk(dev, VBLK))
return (EPERM);
/*
* Do not allow opens of block devices that are
* currently mounted.
*/
if (error = vfs_mountedon(vp))
return (error);
return ((*bdevsw[maj].d_open)(dev, ap->a_mode, S_IFBLK, ap->a_p));
}
return (0);
}
/*
* Vnode op for read
*/
/* ARGSUSED */
spec_read(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
register struct vnode *vp = ap->a_vp;
register struct uio *uio = ap->a_uio;
struct proc *p = uio->uio_procp;
struct buf *bp;
daddr_t bn, nextbn;
long bsize, bscale;
struct partinfo dpart;
int n, on, majordev, (*ioctl)();
int error = 0;
dev_t dev;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ)
panic("spec_read mode");
if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
panic("spec_read proc");
#endif
if (uio->uio_resid == 0)
return (0);
switch (vp->v_type) {
case VCHR:
VOP_UNLOCK(vp);
error = (*cdevsw[major(vp->v_rdev)].d_read)
(vp->v_rdev, uio, ap->a_ioflag);
VOP_LOCK(vp);
return (error);
case VBLK:
if (uio->uio_offset < 0)
return (EINVAL);
bsize = BLKDEV_IOSIZE;
dev = vp->v_rdev;
if ((majordev = major(dev)) < nblkdev &&
(ioctl = bdevsw[majordev].d_ioctl) != NULL &&
(*ioctl)(dev, DIOCGPART, (caddr_t)&dpart, FREAD, p) == 0 &&
dpart.part->p_fstype == FS_BSDFFS &&
dpart.part->p_frag != 0 && dpart.part->p_fsize != 0)
bsize = dpart.part->p_frag * dpart.part->p_fsize;
bscale = bsize / DEV_BSIZE;
do {
bn = (uio->uio_offset / DEV_BSIZE) &~ (bscale - 1);
on = uio->uio_offset % bsize;
n = min((unsigned)(bsize - on), uio->uio_resid);
if (vp->v_lastr + bscale == bn) {
nextbn = bn + bscale;
error = breadn(vp, bn, (int)bsize, &nextbn,
(int *)&bsize, 1, NOCRED, &bp);
} else
error = bread(vp, bn, (int)bsize, NOCRED, &bp);
vp->v_lastr = bn;
n = min(n, bsize - bp->b_resid);
if (error) {
brelse(bp);
return (error);
}
error = uiomove((char *)bp->b_data + on, n, uio);
if (n + on == bsize)
bp->b_flags |= B_AGE;
brelse(bp);
} while (error == 0 && uio->uio_resid > 0 && n != 0);
return (error);
default:
panic("spec_read type");
}
/* NOTREACHED */
}
/*
* Vnode op for write
*/
/* ARGSUSED */
spec_write(ap)
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
register struct vnode *vp = ap->a_vp;
register struct uio *uio = ap->a_uio;
struct proc *p = uio->uio_procp;
struct buf *bp;
daddr_t bn;
int bsize, blkmask;
struct partinfo dpart;
register int n, on;
int error = 0;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_WRITE)
panic("spec_write mode");
if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
panic("spec_write proc");
#endif
switch (vp->v_type) {
case VCHR:
VOP_UNLOCK(vp);
error = (*cdevsw[major(vp->v_rdev)].d_write)
(vp->v_rdev, uio, ap->a_ioflag);
VOP_LOCK(vp);
return (error);
case VBLK:
if (uio->uio_resid == 0)
return (0);
if (uio->uio_offset < 0)
return (EINVAL);
bsize = BLKDEV_IOSIZE;
if ((*bdevsw[major(vp->v_rdev)].d_ioctl)(vp->v_rdev, DIOCGPART,
(caddr_t)&dpart, FREAD, p) == 0) {
if (dpart.part->p_fstype == FS_BSDFFS &&
dpart.part->p_frag != 0 && dpart.part->p_fsize != 0)
bsize = dpart.part->p_frag *
dpart.part->p_fsize;
}
blkmask = (bsize / DEV_BSIZE) - 1;
do {
bn = (uio->uio_offset / DEV_BSIZE) &~ blkmask;
on = uio->uio_offset % bsize;
n = min((unsigned)(bsize - on), uio->uio_resid);
if (n == bsize)
bp = getblk(vp, bn, bsize, 0, 0);
else
error = bread(vp, bn, bsize, NOCRED, &bp);
n = min(n, bsize - bp->b_resid);
if (error) {
brelse(bp);
return (error);
}
error = uiomove((char *)bp->b_data + on, n, uio);
if (n + on == bsize) {
bp->b_flags |= B_AGE;
bawrite(bp);
} else
bdwrite(bp);
} while (error == 0 && uio->uio_resid > 0 && n != 0);
return (error);
default:
panic("spec_write type");
}
/* NOTREACHED */
}
/*
* Device ioctl operation.
*/
/* ARGSUSED */
spec_ioctl(ap)
struct vop_ioctl_args /* {
struct vnode *a_vp;
int a_command;
caddr_t a_data;
int a_fflag;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
dev_t dev = ap->a_vp->v_rdev;
switch (ap->a_vp->v_type) {
case VCHR:
return ((*cdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data,
ap->a_fflag, ap->a_p));
case VBLK:
if (ap->a_command == 0 && (int)ap->a_data == B_TAPE)
if (bdevsw[major(dev)].d_flags & B_TAPE)
return (0);
else
return (1);
return ((*bdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data,
ap->a_fflag, ap->a_p));
default:
panic("spec_ioctl");
/* NOTREACHED */
}
}
/* ARGSUSED */
spec_select(ap)
struct vop_select_args /* {
struct vnode *a_vp;
int a_which;
int a_fflags;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
register dev_t dev;
switch (ap->a_vp->v_type) {
default:
return (1); /* XXX */
case VCHR:
dev = ap->a_vp->v_rdev;
return (*cdevsw[major(dev)].d_select)(dev, ap->a_which, ap->a_p);
}
}
/*
* Synch buffers associated with a block device
*/
/* ARGSUSED */
int
spec_fsync(ap)
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_waitfor;
struct proc *a_p;
} */ *ap;
{
register struct vnode *vp = ap->a_vp;
register struct buf *bp;
struct buf *nbp;
int s;
if (vp->v_type == VCHR)
return (0);
/*
* Flush all dirty buffers associated with a block device.
*/
loop:
s = splbio();
for (bp = vp->v_dirtyblkhd.lh_first; bp; bp = nbp) {
nbp = bp->b_vnbufs.le_next;
if ((bp->b_flags & B_BUSY))
continue;
if ((bp->b_flags & B_DELWRI) == 0)
panic("spec_fsync: not dirty");
bremfree(bp);
bp->b_flags |= B_BUSY;
splx(s);
bawrite(bp);
goto loop;
}
if (ap->a_waitfor == MNT_WAIT) {
while (vp->v_numoutput) {
vp->v_flag |= VBWAIT;
sleep((caddr_t)&vp->v_numoutput, PRIBIO + 1);
}
#ifdef DIAGNOSTIC
if (vp->v_dirtyblkhd.lh_first) {
vprint("spec_fsync: dirty", vp);
goto loop;
}
#endif
}
splx(s);
return (0);
}
/*
* Just call the device strategy routine
*/
spec_strategy(ap)
struct vop_strategy_args /* {
struct buf *a_bp;
} */ *ap;
{
(*bdevsw[major(ap->a_bp->b_dev)].d_strategy)(ap->a_bp);
return (0);
}
/*
* This is a noop, simply returning what one has been given.
*/
spec_bmap(ap)
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
} */ *ap;
{
if (ap->a_vpp != NULL)
*ap->a_vpp = ap->a_vp;
if (ap->a_bnp != NULL)
*ap->a_bnp = ap->a_bn;
return (0);
}
/*
* At the moment we do not do any locking.
*/
/* ARGSUSED */
spec_lock(ap)
struct vop_lock_args /* {
struct vnode *a_vp;
} */ *ap;
{
return (0);
}
/* ARGSUSED */
spec_unlock(ap)
struct vop_unlock_args /* {
struct vnode *a_vp;
} */ *ap;
{
return (0);
}
/*
* Device close routine
*/
/* ARGSUSED */
spec_close(ap)
struct vop_close_args /* {
struct vnode *a_vp;
int a_fflag;
struct ucred *a_cred;
struct proc *a_p;
} */ *ap;
{
register struct vnode *vp = ap->a_vp;
dev_t dev = vp->v_rdev;
int (*devclose) __P((dev_t, int, int, struct proc *));
int mode, error;
switch (vp->v_type) {
case VCHR:
/*
* Hack: a tty device that is a controlling terminal
* has a reference from the session structure.
* We cannot easily tell that a character device is
* a controlling terminal, unless it is the closing
* process' controlling terminal. In that case,
* if the reference count is 2 (this last descriptor
* plus the session), release the reference from the session.
*/
if (vcount(vp) == 2 && ap->a_p &&
vp == ap->a_p->p_session->s_ttyvp) {
vrele(vp);
ap->a_p->p_session->s_ttyvp = NULL;
}
/*
* If the vnode is locked, then we are in the midst
* of forcably closing the device, otherwise we only
* close on last reference.
*/
if (vcount(vp) > 1 && (vp->v_flag & VXLOCK) == 0)
return (0);
devclose = cdevsw[major(dev)].d_close;
mode = S_IFCHR;
break;
case VBLK:
/*
* On last close of a block device (that isn't mounted)
* we must invalidate any in core blocks, so that
* we can, for instance, change floppy disks.
*/
if (error = vinvalbuf(vp, V_SAVE, ap->a_cred, ap->a_p, 0, 0))
return (error);
/*
* We do not want to really close the device if it
* is still in use unless we are trying to close it
* forcibly. Since every use (buffer, vnode, swap, cmap)
* holds a reference to the vnode, and because we mark
* any other vnodes that alias this device, when the
* sum of the reference counts on all the aliased
* vnodes descends to one, we are on last close.
*/
if (vcount(vp) > 1 && (vp->v_flag & VXLOCK) == 0)
return (0);
devclose = bdevsw[major(dev)].d_close;
mode = S_IFBLK;
break;
default:
panic("spec_close: not special");
}
return ((*devclose)(dev, ap->a_fflag, mode, ap->a_p));
}
/*
* Print out the contents of a special device vnode.
*/
spec_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
{
printf("tag VT_NON, dev %d, %d\n", major(ap->a_vp->v_rdev),
minor(ap->a_vp->v_rdev));
}
/*
* Return POSIX pathconf information applicable to special devices.
*/
spec_pathconf(ap)
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
int *a_retval;
} */ *ap;
{
switch (ap->a_name) {
case _PC_LINK_MAX:
*ap->a_retval = LINK_MAX;
return (0);
case _PC_MAX_CANON:
*ap->a_retval = MAX_CANON;
return (0);
case _PC_MAX_INPUT:
*ap->a_retval = MAX_INPUT;
return (0);
case _PC_PIPE_BUF:
*ap->a_retval = PIPE_BUF;
return (0);
case _PC_CHOWN_RESTRICTED:
*ap->a_retval = 1;
return (0);
case _PC_VDISABLE:
*ap->a_retval = _POSIX_VDISABLE;
return (0);
default:
return (EINVAL);
}
/* NOTREACHED */
}
/*
* Special device advisory byte-level locks.
*/
/* ARGSUSED */
spec_advlock(ap)
struct vop_advlock_args /* {
struct vnode *a_vp;
caddr_t a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap;
{
return (EOPNOTSUPP);
}
/*
* Special device failed operation
*/
spec_ebadf()
{
return (EBADF);
}
/*
* Special device bad operation
*/
spec_badop()
{
panic("spec_badop called");
/* NOTREACHED */
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.