70 lines
3.3 KiB
C
70 lines
3.3 KiB
C
/*
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* Copyright (c) 2012 Apple Inc. All rights reserved.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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*
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* This file contains Original Code and/or Modifications of Original Code
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* as defined in and that are subject to the Apple Public Source License
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* Version 2.0 (the 'License'). You may not use this file except in
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* compliance with the License. The rights granted to you under the License
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* may not be used to create, or enable the creation or redistribution of,
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* unlawful or unlicensed copies of an Apple operating system, or to
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* circumvent, violate, or enable the circumvention or violation of, any
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* terms of an Apple operating system software license agreement.
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*
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* Please obtain a copy of the License at
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* http://www.opensource.apple.com/apsl/ and read it before using this file.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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* Please see the License for the specific language governing rights and
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* limitations under the License.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
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*/
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#ifndef MOCKFS_H
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#define MOCKFS_H
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#if MOCKFS
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#include <kern/locks.h>
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#include <miscfs/mockfs/mockfs_fsnode.h>
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#include <sys/kernel_types.h>
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/*
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* mockfs is effectively a "fake" filesystem; the primary motivation for it being that we may have cases
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* where our userspace needs are extremely simple/consistent and can provided by a single binary. mockfs
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* uses an in-memory tree to define the structure for an extremely simple filesystem, which makes the
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* assumption that our root device is in fact a mach-o file, and provides a minimal filesystem to support
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* this: the root directory, a mountpoint for devfs (given that very basic userspace code may assume the
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* existance of /dev/), and an executable representing the root device.
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*
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* The functionality supported by mockfs is minimal: it is read-only, and does not support user initiated IO,
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* but it supports lookup (so it should be possible for the user to access /dev/).
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*
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* mockfs is primarily targeted towards memory-backed devices, and will (when possible) attempt to inform the
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* VM that we are using a memory-backed device, so that we can eschew IO to the backing device completely,
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* and avoid having an extra copy of the data in the UBC (as well as the overhead associated with creating
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* that copy).
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*
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* For the moment, mockfs is not marked in vfs_conf.c as being threadsafe.
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*/
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struct mockfs_mount {
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lck_mtx_t mockfs_mnt_mtx; /* Mount-wide (and tree-wide) mutex */
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mockfs_fsnode_t mockfs_root; /* Root of the node tree */
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boolean_t mockfs_memory_backed; /* Does the backing store reside in memory */
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boolean_t mockfs_physical_memory; /* (valid if memory backed) */
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uint32_t mockfs_memdev_base; /* Base page of the backing store (valid if memory backed) */
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uint64_t mockfs_memdev_size; /* Size of the backing store (valid if memory backed) */
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};
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typedef struct mockfs_mount * mockfs_mount_t;
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#endif /* MOCKFS */
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#endif /* MOCKFS_H */
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