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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/cmn_err.h>
#include <sys/cred.h>
#include <sys/debug.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/procfs.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/var.h>
#include <sys/vfs.h>
#include <sys/vfs_opreg.h>
#include <sys/vnode.h>
#include <sys/mode.h>
#include <sys/signal.h>
#include <sys/user.h>
#include <sys/mount.h>
#include <sys/bitmap.h>
#include <sys/kmem.h>
#include <sys/policy.h>
#include <fs/fs_subr.h>
#include <sys/fs/mntdata.h>
#include <sys/zone.h>
/*
* This is the loadable module wrapper.
*/
#include <sys/modctl.h>
static int mntinit(int, char *);
static mntopts_t mnt_mntopts = {
0,
NULL
};
static vfsdef_t vfw = {
VFSDEF_VERSION,
"mntfs",
mntinit,
VSW_HASPROTO|VSW_STATS|VSW_ZMOUNT,
&mnt_mntopts
};
/*
* Module linkage information for the kernel.
*/
extern struct mod_ops mod_fsops;
static struct modlfs modlfs = {
&mod_fsops, "mount information file system", &vfw
};
static struct modlinkage modlinkage = {
MODREV_1, (void *)&modlfs, NULL
};
int
_init(void)
{
return (mod_install(&modlinkage));
}
int
_info(struct modinfo *modinfop)
{
return (mod_info(&modlinkage, modinfop));
}
/*
* N.B.
* No _fini routine. The module cannot be unloaded once loaded.
* The NO_UNLOAD_STUB in modstubs.s must change if this module
* is ever modified to become unloadable.
*/
extern int mntfstype;
static major_t mnt_major;
static minor_t mnt_minor;
static kmutex_t mnt_minor_lock;
/*
* /mnttab VFS operations vector.
*/
static int mntmount(), mntunmount(), mntroot(), mntstatvfs();
static void
mntinitrootnode(mntnode_t *mnp)
{
struct vnode *vp;
bzero((caddr_t)mnp, sizeof (*mnp));
mnp->mnt_vnode = vn_alloc(KM_SLEEP);
vp = MTOV(mnp);
vp->v_flag = VROOT|VNOCACHE|VNOMAP|VNOSWAP|VNOMOUNT;
vn_setops(vp, mntvnodeops);
vp->v_type = VREG;
vp->v_data = (caddr_t)mnp;
}
static int
mntinit(int fstype, char *name)
{
static const fs_operation_def_t mnt_vfsops_template[] = {
VFSNAME_MOUNT, { .vfs_mount = mntmount },
VFSNAME_UNMOUNT, { .vfs_unmount = mntunmount },
VFSNAME_ROOT, { .vfs_root = mntroot },
VFSNAME_STATVFS, { .vfs_statvfs = mntstatvfs },
NULL, NULL
};
extern const fs_operation_def_t mnt_vnodeops_template[];
int error;
mntfstype = fstype;
ASSERT(mntfstype != 0);
/*
* Associate VFS ops vector with this fstype.
*/
error = vfs_setfsops(fstype, mnt_vfsops_template, NULL);
if (error != 0) {
cmn_err(CE_WARN, "mntinit: bad vfs ops template");
return (error);
}
/* Vnode ops too. */
error = vn_make_ops(name, mnt_vnodeops_template, &mntvnodeops);
if (error != 0) {
(void) vfs_freevfsops_by_type(fstype);
cmn_err(CE_WARN, "mntinit: bad vnode ops template");
return (error);
}
/*
* Assign a unique "device" number (used by stat(2)).
*/
if ((mnt_major = getudev()) == (major_t)-1) {
cmn_err(CE_WARN, "mntinit: can't get unique device number");
mnt_major = 0;
}
mutex_init(&mnt_minor_lock, NULL, MUTEX_DEFAULT, NULL);
return (0);
}
/* ARGSUSED */
static int
mntmount(struct vfs *vfsp, struct vnode *mvp,
struct mounta *uap, struct cred *cr)
{
mntdata_t *mnt;
mntnode_t *mnp;
zone_t *zone = curproc->p_zone;
if (secpolicy_fs_mount(cr, mvp, vfsp) != 0)
return (EPERM);
/*
* You can only mount mnttab in your current zone.
*/
if (zone == global_zone) {
zone_t *mntzone;
mntzone = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
ASSERT(mntzone != NULL);
zone_rele(mntzone);
if (mntzone != zone)
return (EBUSY);
}
/*
* Having the resource be anything but "mnttab" doesn't make sense
*/
vfs_setresource(vfsp, "mnttab", 0);
mnt = kmem_zalloc(sizeof (*mnt), KM_SLEEP);
mutex_enter(&mvp->v_lock);
if ((uap->flags & MS_OVERLAY) == 0 &&
(mvp->v_count > 1 || (mvp->v_flag & VROOT))) {
mutex_exit(&mvp->v_lock);
kmem_free(mnt, sizeof (*mnt));
return (EBUSY);
}
mutex_exit(&mvp->v_lock);
zone_init_ref(&mnt->mnt_zone_ref);
zone_hold_ref(zone, &mnt->mnt_zone_ref, ZONE_REF_MNTFS);
mnp = &mnt->mnt_node;
vfsp->vfs_fstype = mntfstype;
vfsp->vfs_data = (caddr_t)mnt;
/*
* find an available minor device number for this mount.
*/
mutex_enter(&mnt_minor_lock);
do {
mnt_minor = (mnt_minor + 1) & L_MAXMIN32;
vfsp->vfs_dev = makedevice(mnt_major, mnt_minor);
} while (vfs_devismounted(vfsp->vfs_dev));
mutex_exit(&mnt_minor_lock);
vfs_make_fsid(&vfsp->vfs_fsid, vfsp->vfs_dev, mntfstype);
vfsp->vfs_bsize = DEV_BSIZE;
mntinitrootnode(mnp);
MTOV(mnp)->v_vfsp = vfsp;
mnp->mnt_mountvp = mvp;
vn_exists(MTOV(mnp));
return (0);
}
/* ARGSUSED */
static int
mntunmount(struct vfs *vfsp, int flag, struct cred *cr)
{
mntdata_t *mnt = (mntdata_t *)vfsp->vfs_data;
vnode_t *vp = MTOV(&mnt->mnt_node);
if (secpolicy_fs_unmount(cr, vfsp) != 0)
return (EPERM);
/*
* Ensure that no /mnttab vnodes are in use on this mount point.
*/
mutex_enter(&vp->v_lock);
if (vp->v_count > 1 || mnt->mnt_nopen > 0) {
mutex_exit(&vp->v_lock);
return (EBUSY);
}
mutex_exit(&vp->v_lock);
zone_rele_ref(&mnt->mnt_zone_ref, ZONE_REF_MNTFS);
vn_invalid(vp);
vn_free(vp);
kmem_free(mnt, sizeof (*mnt));
return (0);
}
/* ARGSUSED */
static int
mntroot(struct vfs *vfsp, struct vnode **vpp)
{
mntnode_t *mnp = &((mntdata_t *)vfsp->vfs_data)->mnt_node;
struct vnode *vp = MTOV(mnp);
VN_HOLD(vp);
*vpp = vp;
return (0);
}
static int
mntstatvfs(struct vfs *vfsp, struct statvfs64 *sp)
{
dev32_t d32;
bzero((caddr_t)sp, sizeof (*sp));
sp->f_bsize = DEV_BSIZE;
sp->f_frsize = DEV_BSIZE;
sp->f_blocks = (fsblkcnt64_t)0;
sp->f_bfree = (fsblkcnt64_t)0;
sp->f_bavail = (fsblkcnt64_t)0;
sp->f_files = (fsfilcnt64_t)1;
sp->f_ffree = (fsfilcnt64_t)0;
sp->f_favail = (fsfilcnt64_t)0;
(void) cmpldev(&d32, vfsp->vfs_dev);
sp->f_fsid = d32;
(void) strcpy(sp->f_basetype, vfssw[mntfstype].vsw_name);
sp->f_flag = vf_to_stf(vfsp->vfs_flag);
sp->f_namemax = 64; /* quite arbitrary */
bzero(sp->f_fstr, sizeof (sp->f_fstr));
(void) strcpy(sp->f_fstr, "/mnttab");
(void) strcpy(&sp->f_fstr[8], "/mnttab");
return (0);
}
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