1/*
2 * Copyright (c) 2008 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#ifndef _SYS_DECMPFS_H_
29#define _SYS_DECMPFS_H_ 1
30
31#include <sys/kernel_types.h>
32
33#define MAX_DECMPFS_XATTR_SIZE 3802
34
35/*
36 NOTE:  decmpfs can only be used by thread-safe filesystems
37 */
38
39#define DECMPFS_MAGIC 0x636d7066 /* cmpf */
40
41#define DECMPFS_XATTR_NAME "com.apple.decmpfs" /* extended attribute to use for decmpfs */
42
43typedef struct __attribute__((packed)) {
44    /* this structure represents the xattr on disk; the fields below are little-endian */
45    uint32_t compression_magic;
46    uint32_t compression_type;     /* see the enum below */
47    uint64_t uncompressed_size;
48    unsigned char attr_bytes[0];   /* the bytes of the attribute after the header */
49} decmpfs_disk_header;
50
51typedef struct __attribute__((packed)) {
52    /* this structure represents the xattr in memory; the fields below are host-endian */
53    uint32_t attr_size;
54    uint32_t compression_magic;
55    uint32_t compression_type;
56    uint64_t uncompressed_size;
57    unsigned char attr_bytes[0];   /* the bytes of the attribute after the header */
58} decmpfs_header;
59
60/* compression_type values */
61enum {
62    CMP_Type1       = 1, /* uncompressed data in xattr */
63
64    /* additional types defined in AppleFSCompression project */
65
66    CMP_MAX         = 255 /* Highest compression_type supported */
67};
68
69typedef struct {
70    void *buf;
71    user_ssize_t size;
72} decmpfs_vector;
73
74#if KERNEL
75
76#if XNU_KERNEL_PRIVATE
77
78#include <kern/locks.h>
79
80typedef struct decmpfs_cnode {
81    uint8_t cmp_state;
82    uint8_t cmp_minimal_xattr;       /* if non-zero, this file's com.apple.decmpfs xattr contained only the minimal decmpfs_disk_header */
83    uint32_t cmp_type;
84    uint32_t lockcount;
85    void    *lockowner;              /* cnode's lock owner (if a thread is currently holding an exclusive lock) */
86    uint64_t uncompressed_size __attribute__((aligned(8)));
87    uint64_t decompression_flags;
88    lck_rw_t compressed_data_lock;
89} decmpfs_cnode;
90
91/* return values from decmpfs_file_is_compressed */
92enum {
93    FILE_TYPE_UNKNOWN      = 0,
94    FILE_IS_NOT_COMPRESSED = 1,
95    FILE_IS_COMPRESSED     = 2,
96    FILE_IS_CONVERTING     = 3  /* file is converting from compressed to decompressed */
97};
98
99/* vfs entrypoints */
100extern vfs_context_t decmpfs_ctx;
101
102/* client filesystem entrypoints */
103void decmpfs_init(void);
104void decmpfs_cnode_init(decmpfs_cnode *cp);
105void decmpfs_cnode_destroy(decmpfs_cnode *cp);
106
107int decmpfs_hides_rsrc(vfs_context_t ctx, decmpfs_cnode *cp);
108int decmpfs_hides_xattr(vfs_context_t ctx, decmpfs_cnode *cp, const char *xattr);
109
110boolean_t decmpfs_trylock_compressed_data(decmpfs_cnode *cp, int exclusive);
111void decmpfs_lock_compressed_data(decmpfs_cnode *cp, int exclusive);
112void decmpfs_unlock_compressed_data(decmpfs_cnode *cp, int exclusive);
113
114uint32_t decmpfs_cnode_get_vnode_state(decmpfs_cnode *cp);
115void decmpfs_cnode_set_vnode_state(decmpfs_cnode *cp, uint32_t state, int skiplock);
116uint64_t decmpfs_cnode_get_vnode_cached_size(decmpfs_cnode *cp);
117
118int decmpfs_file_is_compressed(vnode_t vp, decmpfs_cnode *cp);
119errno_t decmpfs_validate_compressed_file(vnode_t vp, decmpfs_cnode *cp);
120int decmpfs_decompress_file(vnode_t vp, decmpfs_cnode *cp, off_t toSize, int truncate_okay, int skiplock);  /* if toSize == -1, decompress the entire file */
121int decmpfs_free_compressed_data(vnode_t vp, decmpfs_cnode *cp);
122int decmpfs_update_attributes(vnode_t vp, struct vnode_attr *vap);
123/* the following two routines will set *is_compressed to 0 if the file was converted from compressed to decompressed before data could be fetched from the decompressor */
124errno_t decmpfs_pagein_compressed(struct vnop_pagein_args *ap, int *is_compressed, decmpfs_cnode *cp);
125errno_t decmpfs_read_compressed(struct vnop_read_args *ap, int *is_compressed, decmpfs_cnode *cp);
126
127#endif /* XNU_KERNEL_PRIVATE */
128
129/* types shared between the kernel and kexts */
130typedef int (*decmpfs_validate_compressed_file_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
131typedef void (*decmpfs_adjust_fetch_region_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr, off_t *offset, user_ssize_t *size);
132typedef int (*decmpfs_fetch_uncompressed_data_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr, off_t offset, user_ssize_t size, int nvec, decmpfs_vector *vec, uint64_t *bytes_read);
133typedef int (*decmpfs_free_compressed_data_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
134typedef uint64_t (*decmpfs_get_decompression_flags_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr); // returns flags from the DECMPFS_FLAGS enumeration below
135
136enum {
137    DECMPFS_FLAGS_FORCE_FLUSH_ON_DECOMPRESS = 1 << 0,
138};
139
140/* Versions that are supported for binary compatibility */
141#define DECMPFS_REGISTRATION_VERSION_V1 1
142#define DECMPFS_REGISTRATION_VERSION_V3 3
143
144#define DECMPFS_REGISTRATION_VERSION (DECMPFS_REGISTRATION_VERSION_V3)
145
146typedef struct {
147    int                                   decmpfs_registration;
148    decmpfs_validate_compressed_file_func validate;
149    decmpfs_adjust_fetch_region_func      adjust_fetch;
150    decmpfs_fetch_uncompressed_data_func  fetch;
151    decmpfs_free_compressed_data_func     free_data;
152    decmpfs_get_decompression_flags_func  get_flags;
153} decmpfs_registration;
154
155/* hooks for kexts to call */
156errno_t register_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
157errno_t unregister_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
158
159#endif /* KERNEL */
160
161#endif /* _SYS_DECMPFS_H_ */
162