/* $NetBSD: vfs_hooks.c,v 1.9 2024/12/07 02:27:38 riastradh Exp $ */ /*- * Copyright (c) 2005 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Julio M. Merino Vidal. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * VFS hooks. */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: vfs_hooks.c,v 1.9 2024/12/07 02:27:38 riastradh Exp $"); #include <sys/param.h> #include <sys/errno.h> #include <sys/mount.h> #include <sys/mutex.h> #include <sys/queue.h> #include <sys/sdt.h> LIST_HEAD(vfs_hooks_head, vfs_hooks) vfs_hooks_head = LIST_HEAD_INITIALIZER(vfs_hooks_head); kmutex_t vfs_hooks_lock; void vfs_hooks_init(void) { mutex_init(&vfs_hooks_lock, MUTEX_DEFAULT, IPL_NONE); } int vfs_hooks_attach(struct vfs_hooks *vfs_hooks) { mutex_enter(&vfs_hooks_lock); LIST_INSERT_HEAD(&vfs_hooks_head, vfs_hooks, vfs_hooks_list); mutex_exit(&vfs_hooks_lock); return 0; } int vfs_hooks_detach(struct vfs_hooks *vfs_hooks) { struct vfs_hooks *hp; int ret = 0; mutex_enter(&vfs_hooks_lock); LIST_FOREACH(hp, &vfs_hooks_head, vfs_hooks_list) { if (hp == vfs_hooks) { LIST_REMOVE(hp, vfs_hooks_list); break; } } if (hp == NULL) ret = SET_ERROR(ESRCH); mutex_exit(&vfs_hooks_lock); return ret; } /* * Macro to be used in one of the vfs_hooks_* function for hooks that * return an error code. Calls will stop as soon as one of the hooks * fails. */ #define VFS_HOOKS_W_ERROR(func, fargs, hook, hargs) \ int \ func fargs \ { \ int error; \ struct vfs_hooks *hp; \ \ error = EJUSTRETURN; \ \ mutex_enter(&vfs_hooks_lock); \ LIST_FOREACH(hp, &vfs_hooks_head, vfs_hooks_list) { \ if (hp-> hook != NULL) { \ error = hp-> hook hargs; \ if (error != 0) \ break; \ } \ } \ mutex_exit(&vfs_hooks_lock); \ \ return error; \ } /* * Macro to be used in one of the vfs_hooks_* function for hooks that * do not return any error code. All hooks will be executed * unconditionally. */ #define VFS_HOOKS_WO_ERROR(func, fargs, hook, hargs) \ void \ func fargs \ { \ struct vfs_hooks *hp; \ \ mutex_enter(&vfs_hooks_lock); \ LIST_FOREACH(hp, &vfs_hooks_head, vfs_hooks_list) { \ if (hp-> hook != NULL) \ hp-> hook hargs; \ } \ mutex_exit(&vfs_hooks_lock); \ } /* * Routines to iterate over VFS hooks lists and execute them. */ VFS_HOOKS_WO_ERROR(vfs_hooks_unmount, (struct mount *mp), vh_unmount, (mp)); VFS_HOOKS_W_ERROR(vfs_hooks_reexport, (struct mount *mp, const char *path, void *data), vh_reexport, (mp, path, data));