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 57 struct mockfs_mount { 58 lck_mtx_t mockfs_mnt_mtx; /* Mount-wide (and tree-wide) mutex */ 59 mockfs_fsnode_t mockfs_root; /* Root of the node tree */ 60 boolean_t mockfs_memory_backed; /* Does the backing store reside in memory */ 61 boolean_t mockfs_physical_memory; /* (valid if memory backed) */ 62 uint32_t mockfs_memdev_base; /* Base page of the backing store (valid if memory backed) */ 63 uint64_t mockfs_memdev_size; /* Size of the backing store (valid if memory backed) */ 64 }; 65 66 typedef struct mockfs_mount * mockfs_mount_t; 67 68 #endif /* MOCKFS */ 69 70 #endif /* MOCKFS_H */ 71