fs/doorfs/door_vnops.c

	door_vnops.c revision 45916cd2fec6e79bca5dee0421bd39e3c2910d1e
/*
 * 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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/vnode.h>
#include <sys/door.h>
#include <sys/proc.h>
#include <sys/kmem.h>
#include <sys/debug.h>
#include <sys/cmn_err.h>
#include <fs/fs_subr.h>
#include <sys/zone.h>
#include <sys/tsol/label.h>

kmutex_t    door_knob;
static int  door_open(struct vnode **vpp, int flag, struct cred *cr);
static int  door_close(struct vnode *vp, int flag, int count,
            offset_t offset, struct cred *cr);
static int  door_getattr(struct vnode *vp, struct vattr *vap,
            int flags, struct cred *cr);
static void door_inactive(struct vnode *vp, struct cred *cr);
static int  door_access(struct vnode *vp, int mode, int flags,
            struct cred *cr);
static int  door_realvp(vnode_t *vp, vnode_t **vpp);

struct vfs door_vfs;

struct vnodeops *door_vnodeops;

const fs_operation_def_t door_vnodeops_template[] = {
    VOPNAME_OPEN, door_open,
    VOPNAME_CLOSE, door_close,
    VOPNAME_GETATTR, door_getattr,
    VOPNAME_ACCESS, door_access,
    VOPNAME_INACTIVE, (fs_generic_func_p) door_inactive,
    VOPNAME_FRLOCK, fs_error,
    VOPNAME_REALVP, door_realvp,
    VOPNAME_POLL, fs_error,
    VOPNAME_PATHCONF, fs_error,
    VOPNAME_DISPOSE, fs_error,
    VOPNAME_GETSECATTR, fs_error,
    VOPNAME_SHRLOCK, fs_error,
    NULL, NULL
};

/* ARGSUSED */
static int
door_open(struct vnode **vpp, int flag, struct cred *cr)
{
    /*
     * MAC policy for doors.  Restrict cross-zone open()s so that only
     * door servers in the global zone can have clients from other zones.
     * For other zones, client must be within the same zone as server.
     */
    if (is_system_labeled()) {
        zone_t      *server_zone, *client_zone;
        door_node_t *dp = VTOD((*vpp));

        mutex_enter(&door_knob);
        if (DOOR_INVALID(dp)) {
            mutex_exit(&door_knob);
            return (0);
        }
        client_zone = curproc->p_zone;
        server_zone = dp->door_target->p_zone;
        mutex_exit(&door_knob);
        if (server_zone != global_zone &&
            server_zone != client_zone)
            return (EACCES);
    }
    return (0);
}

/* ARGSUSED */
static int
door_close(
    struct vnode *vp,
    int flag,
    int count,
    offset_t offset,
    struct cred *cr
)
{
    door_node_t *dp = VTOD(vp);

    /*
     * If this is being called from closeall on exit, any doors created
     * by this process should have been revoked already in door_exit.
     */
    ASSERT(dp->door_target != curproc ||
        ((curthread->t_proc_flag & TP_LWPEXIT) == 0));

    /*
     * Deliver an unref if needed.
     *
     * If the count is equal to 2, it means that I'm doing a VOP_CLOSE
     * on the next to last reference for *this* file struct. There may
     * be multiple files pointing to this vnode in which case the v_count
     * will be > 1.
     *
     * The door_active count is bumped during each invocation.
     */
    if (count == 2 && vp->v_count == 1 &&
        (dp->door_flags & (DOOR_UNREF | DOOR_UNREF_MULTI))) {
        mutex_enter(&door_knob);
        if (dp->door_active == 0) {
            /* o.k. to deliver unref now */
            door_deliver_unref(dp);
        } else {
            /* do the unref later */
            dp->door_flags |= DOOR_DELAY;
        }
        mutex_exit(&door_knob);
    }
    return (0);
}

/* ARGSUSED */
static int
door_getattr(struct vnode *vp, struct vattr *vap, int flags, struct cred *cr)
{
    static timestruc_t tzero = {0, 0};
    extern dev_t doordev;

    vap->va_mask = 0;       /* bit-mask of attributes */
    vap->va_type = vp->v_type;  /* vnode type (for create) */
    vap->va_mode = 0777;        /* file access mode */
    vap->va_uid = 0;        /* owner user id */
    vap->va_gid = 0;        /* owner group id */
    vap->va_fsid = doordev;     /* file system id (dev for now) */
    vap->va_nodeid = (ino64_t)0;        /* node id */
    vap->va_nlink = vp->v_count;    /* number of references to file */
    vap->va_size = (u_offset_t)0;       /* file size in bytes */
    vap->va_atime = tzero;      /* time of last access */
    vap->va_mtime = tzero;      /* time of last modification */
    vap->va_ctime = tzero;      /* time file ``created'' */
    vap->va_rdev = doordev;     /* device the file represents */
    vap->va_blksize = 0;        /* fundamental block size */
    vap->va_nblocks = (fsblkcnt64_t)0;  /* # of blocks allocated */
    vap->va_seq = 0;        /* sequence number */

    return (0);
}

/* ARGSUSED */
static void
door_inactive(struct vnode *vp, struct cred *cr)
{
    door_node_t *dp = VTOD(vp);

    mutex_enter(&vp->v_lock);
    /*
     * Once the door_node is unreferenced, it stays unreferenced,
     * so we can simply return if there are active thread bindings;
     * the final door_unbind_thread() will re-invoke us.
     */
    ASSERT(vp->v_count == 1);
    if (dp->door_bound_threads > 0) {
        vp->v_count--;
        mutex_exit(&vp->v_lock);
        return;
    }
    mutex_exit(&vp->v_lock);

    /* if not revoked, remove door from per-process list */
    if (dp->door_target) {
        mutex_enter(&door_knob);
        if (dp->door_target)    /* recheck door_target under lock */
            door_list_delete(dp);
        mutex_exit(&door_knob);
    }
    vn_invalid(vp);
    vn_free(vp);
    kmem_free(dp, sizeof (door_node_t));
}

/*
 * To avoid having bound threads interfere with unref processing, we
 * don't use VN_HOLD/VN_RELE to track threads bound to our private
 * pool.  Instead, we keep a separate counter, also under v_lock.
 */
void
door_bind_thread(door_node_t *dp)
{
    vnode_t *vp = DTOV(dp);

    mutex_enter(&vp->v_lock);
    dp->door_bound_threads++;
    ASSERT(dp->door_bound_threads > 0 && vp->v_count > 0);
    mutex_exit(&vp->v_lock);
}

void
door_unbind_thread(door_node_t *dp)
{
    vnode_t *vp = DTOV(dp);
    int do_inactive = 0;

    mutex_enter(&vp->v_lock);
    ASSERT(dp->door_bound_threads > 0);
    if (--dp->door_bound_threads == 0 && vp->v_count == 0) {
        /* set up for inactive handling */
        vp->v_count++;
        do_inactive = 1;
    }
    mutex_exit(&vp->v_lock);

    if (do_inactive)
        door_inactive(vp, NULL);
}

/* ARGSUSED */
static int
door_access(struct vnode *vp, int mode, int flags, struct cred *cr)
{
    return (0);
}

/* ARGSUSED */
static int
door_realvp(vnode_t *vp, vnode_t **vpp)
{
    *vpp = vp;
    return (0);
}