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
61 enum {
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
79 /*
80 * This single field is to be interpreted differently depending on the
81 * corresponding item type.
82 * For regular files: it is a 64bits-encoded logical size
83 * For directories: it is a 64bits-encoded number of children (ie st_nlink - 2)
84 * For packages: it is 40bits encoded size and 24bits number of children at root
85 */
86 typedef struct __attribute__((packed)) {
87 uint64_t value;
88 } decmpfs_raw_item_size;
89
90 #define DECMPFS_PKG_SIZE_MASK 0x000000ffffffffffULL
91 #define DECMPFS_PKG_COUNT_MASK 0xffffff
92 #define DECMPFS_PKG_CHLD_COUNT_SHIFT 40
93
94 #define DECMPFS_PKG_SIZE(x) ((x).value & DECMPFS_PKG_SIZE_MASK)
95 #define DECMPFS_PKG_CHLD_COUNT(x) ((uint32_t)(((x).value >> DECMPFS_PKG_CHLD_COUNT_SHIFT) & DECMPFS_PKG_COUNT_MASK))
96 #define DECMPFS_PKG_VALUE_FROM_SIZE_COUNT(size, count) \
97 (((size) & DECMPFS_PKG_SIZE_MASK) | ((uint64_t)(count) << DECMPFS_PKG_CHLD_COUNT_SHIFT))
98
99 /* Dataless file or directory */
100 #define DATALESS_CMPFS_TYPE 0x80000001
101
102 /* Dataless package, with number of root children and total size encoded on disk */
103 #define DATALESS_PKG_CMPFS_TYPE 0x80000002
104
105
106 static inline bool
decmpfs_type_is_dataless(uint32_t cmp_type)107 decmpfs_type_is_dataless(uint32_t cmp_type)
108 {
109 return cmp_type == DATALESS_CMPFS_TYPE || cmp_type == DATALESS_PKG_CMPFS_TYPE;
110 }
111
112 typedef struct __attribute__((packed)) {
113 /* this structure represents the xattr on disk; the fields below are little-endian */
114 uint32_t compression_magic;
115 uint32_t compression_type; /* see the enum below */
116 union {
117 uint64_t uncompressed_size; /* compatility accessor */
118 decmpfs_raw_item_size _size;
119 };
120 unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
121 } decmpfs_disk_header;
122
123 typedef struct __attribute__((packed)) {
124 /* this structure represents the xattr in memory; the fields below are host-endian */
125 uint32_t attr_size;
126 uint32_t compression_magic;
127 uint32_t compression_type;
128 union {
129 /*
130 * although uncompressed_size remains available for backward-compatibility reasons
131 * the uncompressed size and nchildren should be accessed using the inline helpers
132 * below
133 */
134 uint64_t uncompressed_size;
135 decmpfs_raw_item_size _size;
136 };
137 unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
138 } decmpfs_header;
139
140 static inline uint64_t
decmpfs_get_uncompressed_size(const decmpfs_header * hdr)141 decmpfs_get_uncompressed_size(const decmpfs_header *hdr)
142 {
143 if (hdr->compression_magic == DECMPFS_MAGIC && hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
144 return DECMPFS_PKG_SIZE(hdr->_size);
145 }
146
147 return hdr->uncompressed_size;
148 }
149
150 static inline uint32_t
decmpfs_get_directory_entries(const decmpfs_header * hdr)151 decmpfs_get_directory_entries(const decmpfs_header *hdr)
152 {
153 if (hdr->compression_magic == DECMPFS_MAGIC && hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
154 return DECMPFS_PKG_CHLD_COUNT(hdr->_size);
155 }
156
157 return (uint32_t)hdr->uncompressed_size;
158 }
159
160 /* compression_type values */
161 enum {
162 CMP_Type1 = 1,/* uncompressed data in xattr */
163
164 /* additional types defined in AppleFSCompression project */
165
166 CMP_MAX = 255/* Highest compression_type supported */
167 };
168
169 typedef struct {
170 void *buf;
171 user_ssize_t size;
172 } decmpfs_vector;
173
174 #ifdef KERNEL
175
176 #ifdef XNU_KERNEL_PRIVATE
177
178 #include <kern/locks.h>
179
180 struct decmpfs_cnode {
181 uint8_t cmp_state;
182 uint8_t cmp_minimal_xattr; /* if non-zero, this file's com.apple.decmpfs xattr contained only the minimal decmpfs_disk_header */
183 uint32_t cmp_type;
184 uint32_t lockcount;
185 void *lockowner; /* cnode's lock owner (if a thread is currently holding an exclusive lock) */
186 uint64_t uncompressed_size __attribute__((aligned(8)));
187 uint64_t nchildren __attribute__((aligned(8))); /* for dataless directories (incl. packages) */
188 uint64_t total_size __attribute__((aligned(8)));/* for dataless directories (incl. packages) */
189 uint64_t decompression_flags;
190 lck_rw_t compressed_data_lock;
191 };
192
193 #endif // XNU_KERNEL_PRIVATE
194
195 typedef struct decmpfs_cnode decmpfs_cnode;
196
197 /* return values from decmpfs_file_is_compressed */
198 enum {
199 FILE_TYPE_UNKNOWN = 0,
200 FILE_IS_NOT_COMPRESSED = 1,
201 FILE_IS_COMPRESSED = 2,
202 FILE_IS_CONVERTING = 3/* file is converting from compressed to decompressed */
203 };
204
205 /* vfs entrypoints */
206 extern vfs_context_t decmpfs_ctx;
207
208 /* client filesystem entrypoints */
209 void decmpfs_init(void);
210 decmpfs_cnode *decmpfs_cnode_alloc(void);
211 void decmpfs_cnode_free(decmpfs_cnode *dp);
212 void decmpfs_cnode_init(decmpfs_cnode *cp);
213 void decmpfs_cnode_destroy(decmpfs_cnode *cp);
214
215 int decmpfs_hides_rsrc(vfs_context_t ctx, decmpfs_cnode *cp);
216 int decmpfs_hides_xattr(vfs_context_t ctx, decmpfs_cnode *cp, const char *xattr);
217
218 bool decmpfs_trylock_compressed_data(decmpfs_cnode *cp, int exclusive);
219 void decmpfs_lock_compressed_data(decmpfs_cnode *cp, int exclusive);
220 void decmpfs_unlock_compressed_data(decmpfs_cnode *cp, int exclusive);
221
222 uint32_t decmpfs_cnode_get_vnode_state(decmpfs_cnode *cp);
223 void decmpfs_cnode_set_vnode_state(decmpfs_cnode *cp, uint32_t state, int skiplock);
224 uint64_t decmpfs_cnode_get_vnode_cached_size(decmpfs_cnode *cp);
225 uint64_t decmpfs_cnode_get_vnode_cached_nchildren(decmpfs_cnode *cp);
226 uint64_t decmpfs_cnode_get_vnode_cached_total_size(decmpfs_cnode *cp);
227 void decmpfs_cnode_set_vnode_cached_size(decmpfs_cnode *cp, uint64_t size);
228 void decmpfs_cnode_set_vnode_cached_nchildren(decmpfs_cnode *cp, uint64_t nchildren);
229 void decmpfs_cnode_set_vnode_cached_total_size(decmpfs_cnode *cp, uint64_t total_sz);
230 uint32_t decmpfs_cnode_cmp_type(decmpfs_cnode *cp);
231
232 int decmpfs_file_is_compressed(vnode_t vp, decmpfs_cnode *cp);
233 errno_t decmpfs_validate_compressed_file(vnode_t vp, decmpfs_cnode *cp);
234 int decmpfs_decompress_file(vnode_t vp, decmpfs_cnode *cp, off_t toSize, int truncate_okay, int skiplock); /* if toSize == -1, decompress the entire file */
235 int decmpfs_free_compressed_data(vnode_t vp, decmpfs_cnode *cp);
236 int decmpfs_update_attributes(vnode_t vp, struct vnode_attr *vap);
237 /* 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 */
238 errno_t decmpfs_pagein_compressed(struct vnop_pagein_args *ap, int *is_compressed, decmpfs_cnode *cp);
239 errno_t decmpfs_read_compressed(struct vnop_read_args *ap, int *is_compressed, decmpfs_cnode *cp);
240
241 /* types shared between the kernel and kexts */
242 typedef int (*decmpfs_validate_compressed_file_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
243 typedef void (*decmpfs_adjust_fetch_region_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr, off_t *offset, user_ssize_t *size);
244 typedef 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);
245 typedef int (*decmpfs_free_compressed_data_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
246 typedef 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
247
248 enum {
249 DECMPFS_FLAGS_FORCE_FLUSH_ON_DECOMPRESS = 1 << 0,
250 };
251
252 /* Versions that are supported for binary compatibility */
253 #define DECMPFS_REGISTRATION_VERSION_V1 1
254 #define DECMPFS_REGISTRATION_VERSION_V3 3
255
256 #define DECMPFS_REGISTRATION_VERSION (DECMPFS_REGISTRATION_VERSION_V3)
257
258 typedef struct {
259 int decmpfs_registration;
260 decmpfs_validate_compressed_file_func validate;
261 decmpfs_adjust_fetch_region_func adjust_fetch;
262 decmpfs_fetch_uncompressed_data_func fetch;
263 decmpfs_free_compressed_data_func free_data;
264 decmpfs_get_decompression_flags_func get_flags;
265 } decmpfs_registration;
266
267 /* hooks for kexts to call */
268 errno_t register_decmpfs_decompressor(uint32_t compression_type, const decmpfs_registration *registration);
269 errno_t unregister_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
270
271 #endif /* KERNEL */
272
273 #endif /* _SYS_DECMPFS_H_ */
274