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 <stdbool.h>
32#include <sys/kdebug.h>
33#include <sys/kernel_types.h>
34#include <sys/vnode.h>
35
36/*
37 * Please switch on @DECMPFS_ENABLE_KDEBUG_TRACES to enable tracepoints.
38 * Tracepoints are compiled out by default to eliminate any overhead due to
39 * kernel tracing.
40 *
41 * #define DECMPFS_ENABLE_KDEBUG_TRACES 1
42 */
43#if DECMPFS_ENABLE_KDEBUG_TRACES
44#define DECMPFS_EMIT_TRACE_ENTRY(D, ...)\
45 KDBG_FILTERED((D) | DBG_FUNC_START, ## __VA_ARGS__)
46#define DECMPFS_EMIT_TRACE_RETURN(D, ...)\
47 KDBG_FILTERED((D) | DBG_FUNC_END, ##__VA_ARGS__)
48#else
49#define DECMPFS_EMIT_TRACE_ENTRY(D, ...) do {} while (0)
50#define DECMPFS_EMIT_TRACE_RETURN(D, ...) do {} while (0)
51#endif /* DECMPFS_ENABLE_KDEBUG_TRACES */
52
53/*
54 * KERNEL_DEBUG related definitions for decmpfs.
55 *
56 * Please NOTE: The Class DBG_FSYSTEM = 3, and Subclass DBG_DECMP = 0x12, so
57 * these debug codes are of the form 0x0312nnnn.
58 */
59#define DECMPDBG_CODE(code) FSDBG_CODE(DBG_DECMP, code)
60
61enum {
62 DECMPDBG_DECOMPRESS_FILE = DECMPDBG_CODE(0), /* 0x03120000 */
63 DECMPDBG_FETCH_COMPRESSED_HEADER = DECMPDBG_CODE(1), /* 0x03120004 */
64 DECMPDBG_FETCH_UNCOMPRESSED_DATA = DECMPDBG_CODE(2), /* 0x03120008 */
65 DECMPDBG_FREE_COMPRESSED_DATA = DECMPDBG_CODE(4), /* 0x03120010 */
66 DECMPDBG_FILE_IS_COMPRESSED = DECMPDBG_CODE(5), /* 0x03120014 */
67};
68
69#define MAX_DECMPFS_XATTR_SIZE 3802
70
71/*
72 NOTE: decmpfs can only be used by thread-safe filesystems
73 */
74
75#define DECMPFS_MAGIC 0x636d7066 /* cmpf */
76
77#define DECMPFS_XATTR_NAME "com.apple.decmpfs" /* extended attribute to use for decmpfs */
78
79typedef struct __attribute__((packed)) {
80 /* this structure represents the xattr on disk; the fields below are little-endian */
81 uint32_t compression_magic;
82 uint32_t compression_type; /* see the enum below */
83 uint64_t uncompressed_size;
84 unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
85} decmpfs_disk_header;
86
87typedef struct __attribute__((packed)) {
88 /* this structure represents the xattr in memory; the fields below are host-endian */
89 uint32_t attr_size;
90 uint32_t compression_magic;
91 uint32_t compression_type;
92 uint64_t uncompressed_size;
93 unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
94} decmpfs_header;
95
96/* compression_type values */
97enum {
98 CMP_Type1 = 1, /* uncompressed data in xattr */
99
100 /* additional types defined in AppleFSCompression project */
101
102 CMP_MAX = 255 /* Highest compression_type supported */
103};
104
105typedef struct {
106 void *buf;
107 user_ssize_t size;
108} decmpfs_vector;
109
110#ifdef KERNEL
111
112#ifdef XNU_KERNEL_PRIVATE
113
114#include <kern/locks.h>
115
116struct decmpfs_cnode {
117 uint8_t cmp_state;
118 uint8_t cmp_minimal_xattr; /* if non-zero, this file's com.apple.decmpfs xattr contained only the minimal decmpfs_disk_header */
119 uint32_t cmp_type;
120 uint32_t lockcount;
121 void *lockowner; /* cnode's lock owner (if a thread is currently holding an exclusive lock) */
122 uint64_t uncompressed_size __attribute__((aligned(8)));
123 uint64_t decompression_flags;
124 lck_rw_t compressed_data_lock;
125};
126
127#endif // XNU_KERNEL_PRIVATE
128
129typedef struct decmpfs_cnode decmpfs_cnode;
130
131/* return values from decmpfs_file_is_compressed */
132enum {
133 FILE_TYPE_UNKNOWN = 0,
134 FILE_IS_NOT_COMPRESSED = 1,
135 FILE_IS_COMPRESSED = 2,
136 FILE_IS_CONVERTING = 3 /* file is converting from compressed to decompressed */
137};
138
139/* vfs entrypoints */
140extern vfs_context_t decmpfs_ctx;
141
142/* client filesystem entrypoints */
143void decmpfs_init(void);
144decmpfs_cnode *decmpfs_cnode_alloc(void);
145void decmpfs_cnode_free(decmpfs_cnode *dp);
146void decmpfs_cnode_init(decmpfs_cnode *cp);
147void decmpfs_cnode_destroy(decmpfs_cnode *cp);
148
149int decmpfs_hides_rsrc(vfs_context_t ctx, decmpfs_cnode *cp);
150int decmpfs_hides_xattr(vfs_context_t ctx, decmpfs_cnode *cp, const char *xattr);
151
152bool decmpfs_trylock_compressed_data(decmpfs_cnode *cp, int exclusive);
153void decmpfs_lock_compressed_data(decmpfs_cnode *cp, int exclusive);
154void decmpfs_unlock_compressed_data(decmpfs_cnode *cp, int exclusive);
155
156uint32_t decmpfs_cnode_get_vnode_state(decmpfs_cnode *cp);
157void decmpfs_cnode_set_vnode_state(decmpfs_cnode *cp, uint32_t state, int skiplock);
158uint64_t decmpfs_cnode_get_vnode_cached_size(decmpfs_cnode *cp);
159uint32_t decmpfs_cnode_cmp_type(decmpfs_cnode *cp);
160
161int decmpfs_file_is_compressed(vnode_t vp, decmpfs_cnode *cp);
162errno_t decmpfs_validate_compressed_file(vnode_t vp, decmpfs_cnode *cp);
163int decmpfs_decompress_file(vnode_t vp, decmpfs_cnode *cp, off_t toSize, int truncate_okay, int skiplock); /* if toSize == -1, decompress the entire file */
164int decmpfs_free_compressed_data(vnode_t vp, decmpfs_cnode *cp);
165int decmpfs_update_attributes(vnode_t vp, struct vnode_attr *vap);
166/* 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 */
167errno_t decmpfs_pagein_compressed(struct vnop_pagein_args *ap, int *is_compressed, decmpfs_cnode *cp);
168errno_t decmpfs_read_compressed(struct vnop_read_args *ap, int *is_compressed, decmpfs_cnode *cp);
169
170/* types shared between the kernel and kexts */
171typedef int (*decmpfs_validate_compressed_file_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
172typedef void (*decmpfs_adjust_fetch_region_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr, off_t *offset, user_ssize_t *size);
173typedef 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);
174typedef int (*decmpfs_free_compressed_data_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
175typedef 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
176
177enum {
178 DECMPFS_FLAGS_FORCE_FLUSH_ON_DECOMPRESS = 1 << 0,
179};
180
181/* Versions that are supported for binary compatibility */
182#define DECMPFS_REGISTRATION_VERSION_V1 1
183#define DECMPFS_REGISTRATION_VERSION_V3 3
184
185#define DECMPFS_REGISTRATION_VERSION (DECMPFS_REGISTRATION_VERSION_V3)
186
187typedef struct {
188 int decmpfs_registration;
189 decmpfs_validate_compressed_file_func validate;
190 decmpfs_adjust_fetch_region_func adjust_fetch;
191 decmpfs_fetch_uncompressed_data_func fetch;
192 decmpfs_free_compressed_data_func free_data;
193 decmpfs_get_decompression_flags_func get_flags;
194} decmpfs_registration;
195
196/* hooks for kexts to call */
197errno_t register_decmpfs_decompressor(uint32_t compression_type, const decmpfs_registration *registration);
198errno_t unregister_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
199
200#endif /* KERNEL */
201
202#endif /* _SYS_DECMPFS_H_ */
203