1/*
2 * Copyright (c) 2012 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29#ifndef MOCKFS_H
30#define MOCKFS_H
31
32#if MOCKFS
33
34#include <kern/locks.h>
35#include <miscfs/mockfs/mockfs_fsnode.h>
36#include <sys/kernel_types.h>
37
38/*
39 * mockfs is effectively a "fake" filesystem; the primary motivation for it being that we may have cases
40 *   where our userspace needs are extremely simple/consistent and can provided by a single binary.  mockfs
41 *   uses an in-memory tree to define the structure for an extremely simple filesystem, which makes the
42 *   assumption that our root device is in fact a mach-o file, and provides a minimal filesystem to support
43 *   this:  the root directory, a mountpoint for devfs (given that very basic userspace code may assume the
44 *   existance of /dev/), and an executable representing the root device.
45 *
46 * The functionality supported by mockfs is minimal: it is read-only, and does not support user initiated IO,
47 *   but it supports lookup (so it should be possible for the user to access /dev/).
48 *
49 * mockfs is primarily targeted towards memory-backed devices, and will (when possible) attempt to inform the
50 *   VM that we are using a memory-backed device, so that we can eschew IO to the backing device completely,
51 *   and avoid having an extra copy of the data in the UBC (as well as the overhead associated with creating
52 *   that copy).
53 *
54 * For the moment, mockfs is not marked in vfs_conf.c as being threadsafe.
55 */
56
57extern lck_attr_t     * mockfs_mtx_attr;
58extern lck_grp_attr_t * mockfs_grp_attr;
59extern lck_grp_t      * mockfs_mtx_grp;
60
61struct mockfs_mount {
62	lck_mtx_t       mockfs_mnt_mtx;         /* Mount-wide (and tree-wide) mutex */
63	mockfs_fsnode_t mockfs_root;            /* Root of the node tree */
64	boolean_t       mockfs_memory_backed;   /* Does the backing store reside in memory */
65	boolean_t       mockfs_physical_memory; /* (valid if memory backed) */
66	uint32_t        mockfs_memdev_base;     /* Base page of the backing store (valid if memory backed) */
67	uint64_t        mockfs_memdev_size;     /* Size of the backing store (valid if memory backed) */
68};
69
70typedef struct mockfs_mount * mockfs_mount_t;
71
72#endif /* MOCKFS */
73
74#endif /* MOCKFS_H */
75
76