freebsd-skq/sys/miscfs/kernfs/kernfs_vfsops.c
dg a4ec59246f Fixed panic that resulted from mmaping files in kernfs and procfs. A
regular user could panic the machine with a simple "tail /proc/curproc/mem"
command. The problem was twofold: both kernfs and procfs didn't fill in
the mnt_stat statfs struct (which would later lead to an integer divide
fault in the vnode pager), and kernfs bogusly paniced if a bmap was
attempted.

Reviewed by:	John Dyson
1995-05-25 01:35:24 +00:00

350 lines
7.4 KiB
C

/*
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software donated to Berkeley by
* Jan-Simon Pendry.
*
* 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.
*
* @(#)kernfs_vfsops.c 8.4 (Berkeley) 1/21/94
* $Id: kernfs_vfsops.c,v 1.8 1995/03/16 20:23:38 wollman Exp $
*/
/*
* Kernel params Filesystem
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/types.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <miscfs/specfs/specdev.h>
#include <miscfs/kernfs/kernfs.h>
struct vnode *rrootvp;
int kernfs_statfs __P((struct mount *, struct statfs *, struct proc *));
/*
* Create a vnode for a character device.
*/
int
cdevvp(dev, vpp)
dev_t dev;
struct vnode **vpp;
{
register struct vnode *vp;
struct vnode *nvp;
int error;
if (dev == NODEV)
return (0);
error = getnewvnode(VT_NON, (struct mount *)0, spec_vnodeop_p, &nvp);
if (error) {
*vpp = 0;
return (error);
}
vp = nvp;
vp->v_type = VCHR;
nvp = checkalias(vp, dev, (struct mount *)0);
if (nvp) {
vput(vp);
vp = nvp;
}
*vpp = vp;
return (0);
}
int
kernfs_init()
{
int cmaj;
int bmaj = major(rootdev);
int error = ENXIO;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_init\n"); /* printed during system boot */
#endif
for (cmaj = 0; cmaj < nchrdev; cmaj++) {
if (cdevsw[cmaj].d_open == bdevsw[bmaj].d_open) {
dev_t cdev = makedev(cmaj, minor(rootdev));
error = cdevvp(cdev, &rrootvp);
if (error == 0)
break;
}
}
if (error) {
printf("kernfs: no raw boot device\n");
rrootvp = 0;
}
return (0);
}
/*
* Mount the Kernel params filesystem
*/
int
kernfs_mount(mp, path, data, ndp, p)
struct mount *mp;
char *path;
caddr_t data;
struct nameidata *ndp;
struct proc *p;
{
int error = 0;
u_int size;
struct kernfs_mount *fmp;
struct vnode *rvp;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_mount(mp = %x)\n", mp);
#endif
/*
* Update is a no-op
*/
if (mp->mnt_flag & MNT_UPDATE)
return (EOPNOTSUPP);
error = getnewvnode(VT_KERNFS, mp, kernfs_vnodeop_p, &rvp); /* XXX */
if (error)
return (error);
MALLOC(fmp, struct kernfs_mount *, sizeof(struct kernfs_mount),
M_UFSMNT, M_WAITOK); /* XXX */
rvp->v_type = VDIR;
rvp->v_flag |= VROOT;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_mount: root vp = %x\n", rvp);
#endif
fmp->kf_root = rvp;
mp->mnt_flag |= MNT_LOCAL;
mp->mnt_data = (qaddr_t) fmp;
getnewfsid(mp, MOUNT_KERNFS);
(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
bcopy("kernfs", mp->mnt_stat.f_mntfromname, sizeof("kernfs"));
(void)kernfs_statfs(mp, &mp->mnt_stat, p);
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_mount: at %s\n", mp->mnt_stat.f_mntonname);
#endif
return (0);
}
int
kernfs_start(mp, flags, p)
struct mount *mp;
int flags;
struct proc *p;
{
return (0);
}
int
kernfs_unmount(mp, mntflags, p)
struct mount *mp;
int mntflags;
struct proc *p;
{
int error;
int flags = 0;
struct vnode *rootvp = VFSTOKERNFS(mp)->kf_root;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_unmount(mp = %x)\n", mp);
#endif
if (mntflags & MNT_FORCE) {
/* kernfs can never be rootfs so don't check for it */
if (!doforce)
return (EINVAL);
flags |= FORCECLOSE;
}
/*
* Clear out buffer cache. I don't think we
* ever get anything cached at this level at the
* moment, but who knows...
*/
if (rootvp->v_usecount > 1)
return (EBUSY);
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_unmount: calling vflush\n");
#endif
error = vflush(mp, rootvp, flags);
if (error)
return (error);
#ifdef KERNFS_DIAGNOSTIC
vprint("kernfs root", rootvp);
#endif
/*
* Release reference on underlying root vnode
*/
vrele(rootvp);
/*
* And blow it away for future re-use
*/
vgone(rootvp);
/*
* Finally, throw away the kernfs_mount structure
*/
free(mp->mnt_data, M_UFSMNT); /* XXX */
mp->mnt_data = 0;
return 0;
}
int
kernfs_root(mp, vpp)
struct mount *mp;
struct vnode **vpp;
{
struct vnode *vp;
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_root(mp = %x)\n", mp);
#endif
/*
* Return locked reference to root.
*/
vp = VFSTOKERNFS(mp)->kf_root;
VREF(vp);
VOP_LOCK(vp);
*vpp = vp;
return (0);
}
int
kernfs_quotactl(mp, cmd, uid, arg, p)
struct mount *mp;
int cmd;
uid_t uid;
caddr_t arg;
struct proc *p;
{
return (EOPNOTSUPP);
}
int
kernfs_statfs(mp, sbp, p)
struct mount *mp;
struct statfs *sbp;
struct proc *p;
{
#ifdef KERNFS_DIAGNOSTIC
printf("kernfs_statfs(mp = %x)\n", mp);
#endif
sbp->f_type = MOUNT_KERNFS;
sbp->f_flags = 0;
sbp->f_bsize = DEV_BSIZE;
sbp->f_iosize = DEV_BSIZE;
sbp->f_blocks = 2; /* 1K to keep df happy */
sbp->f_bfree = 0;
sbp->f_bavail = 0;
sbp->f_files = 0;
sbp->f_ffree = 0;
if (sbp != &mp->mnt_stat) {
bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
}
return (0);
}
int
kernfs_sync(mp, waitfor)
struct mount *mp;
int waitfor;
{
return (0);
}
/*
* Kernfs flat namespace lookup.
* Currently unsupported.
*/
int
kernfs_vget(mp, ino, vpp)
struct mount *mp;
ino_t ino;
struct vnode **vpp;
{
return (EOPNOTSUPP);
}
int
kernfs_fhtovp(mp, fhp, setgen, vpp)
struct mount *mp;
struct fid *fhp;
int setgen;
struct vnode **vpp;
{
return (EOPNOTSUPP);
}
int
kernfs_vptofh(vp, fhp)
struct vnode *vp;
struct fid *fhp;
{
return (EOPNOTSUPP);
}
struct vfsops kernfs_vfsops = {
kernfs_mount,
kernfs_start,
kernfs_unmount,
kernfs_root,
kernfs_quotactl,
kernfs_statfs,
kernfs_sync,
kernfs_vget,
kernfs_fhtovp,
kernfs_vptofh,
kernfs_init,
};
VFS_SET(kernfs_vfsops, kernfs, MOUNT_KERNFS, VFCF_SYNTHETIC);