139 lines
4.0 KiB
C
139 lines
4.0 KiB
C
/* $NetBSD: vfs_hooks.c,v 1.6 2009/03/15 17:14:40 cegger Exp $ */
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/*-
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* Copyright (c) 2005 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Julio M. Merino Vidal.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* VFS hooks.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: vfs_hooks.c,v 1.6 2009/03/15 17:14:40 cegger Exp $");
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <sys/mount.h>
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#include <sys/mutex.h>
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LIST_HEAD(vfs_hooks_head, vfs_hooks) vfs_hooks_head =
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LIST_HEAD_INITIALIZER(vfs_hooks_head);
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kmutex_t vfs_hooks_lock;
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void
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vfs_hooks_init(void)
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{
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mutex_init(&vfs_hooks_lock, MUTEX_DEFAULT, IPL_NONE);
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}
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int
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vfs_hooks_attach(struct vfs_hooks *vfs_hooks)
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{
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mutex_enter(&vfs_hooks_lock);
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LIST_INSERT_HEAD(&vfs_hooks_head, vfs_hooks, vfs_hooks_list);
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mutex_exit(&vfs_hooks_lock);
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return (0);
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}
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int
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vfs_hooks_detach(struct vfs_hooks *vfs_hooks)
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{
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struct vfs_hooks *hp;
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int ret = 0;
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mutex_enter(&vfs_hooks_lock);
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LIST_FOREACH(hp, &vfs_hooks_head, vfs_hooks_list) {
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if (hp == vfs_hooks) {
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LIST_REMOVE(hp, vfs_hooks_list);
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break;
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}
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}
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if (hp == NULL)
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ret = ESRCH;
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mutex_exit(&vfs_hooks_lock);
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return (ret);
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}
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/*
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* Macro to be used in one of the vfs_hooks_* function for hooks that
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* return an error code. Calls will stop as soon as one of the hooks
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* fails.
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*/
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#define VFS_HOOKS_W_ERROR(func, fargs, hook, hargs) \
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int \
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func fargs \
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{ \
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int error; \
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struct vfs_hooks *hp; \
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\
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error = EJUSTRETURN; \
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\
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mutex_enter(&vfs_hooks_lock); \
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LIST_FOREACH(hp, &vfs_hooks_head, vfs_hooks_list) { \
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if (hp-> hook != NULL) { \
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error = hp-> hook hargs; \
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if (error != 0) \
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break; \
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} \
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} \
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mutex_exit(&vfs_hooks_lock); \
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\
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return error; \
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}
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/*
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* Macro to be used in one of the vfs_hooks_* function for hooks that
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* do not return any error code. All hooks will be executed
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* unconditionally.
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*/
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#define VFS_HOOKS_WO_ERROR(func, fargs, hook, hargs) \
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void \
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func fargs \
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{ \
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struct vfs_hooks *hp; \
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\
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mutex_enter(&vfs_hooks_lock); \
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LIST_FOREACH(hp, &vfs_hooks_head, vfs_hooks_list) { \
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if (hp-> hook != NULL) \
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hp-> hook hargs; \
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} \
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mutex_exit(&vfs_hooks_lock); \
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}
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/*
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* Routines to iterate over VFS hooks lists and execute them.
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*/
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VFS_HOOKS_WO_ERROR(vfs_hooks_unmount, (struct mount *mp), vh_unmount, (mp));
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VFS_HOOKS_W_ERROR(vfs_hooks_reexport, (struct mount *mp, const char *path, void *data), vh_reexport, (mp, path, data));
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