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 #include <sys/cdefs.h>
36
37 __BEGIN_DECLS
38 /*
39 * Please switch on @DECMPFS_ENABLE_KDEBUG_TRACES to enable tracepoints.
40 * Tracepoints are compiled out by default to eliminate any overhead due to
41 * kernel tracing.
42 *
43 * #define DECMPFS_ENABLE_KDEBUG_TRACES 1
44 */
45 #if DECMPFS_ENABLE_KDEBUG_TRACES
46 #define DECMPFS_EMIT_TRACE_ENTRY(D, ...) \
47 KDBG_FILTERED((D) | DBG_FUNC_START, ## __VA_ARGS__)
48 #define DECMPFS_EMIT_TRACE_RETURN(D, ...) \
49 KDBG_FILTERED((D) | DBG_FUNC_END, ##__VA_ARGS__)
50 #else
51 #define DECMPFS_EMIT_TRACE_ENTRY(D, ...) do {} while (0)
52 #define DECMPFS_EMIT_TRACE_RETURN(D, ...) do {} while (0)
53 #endif /* DECMPFS_ENABLE_KDEBUG_TRACES */
54
55 /*
56 * KERNEL_DEBUG related definitions for decmpfs.
57 *
58 * Please NOTE: The Class DBG_FSYSTEM = 3, and Subclass DBG_DECMP = 0x12, so
59 * these debug codes are of the form 0x0312nnnn.
60 */
61 #define DECMPDBG_CODE(code) FSDBG_CODE(DBG_DECMP, code)
62
63 enum {
64 DECMPDBG_DECOMPRESS_FILE = DECMPDBG_CODE(0),/* 0x03120000 */
65 DECMPDBG_FETCH_COMPRESSED_HEADER = DECMPDBG_CODE(1),/* 0x03120004 */
66 DECMPDBG_FETCH_UNCOMPRESSED_DATA = DECMPDBG_CODE(2),/* 0x03120008 */
67 DECMPDBG_FREE_COMPRESSED_DATA = DECMPDBG_CODE(4),/* 0x03120010 */
68 DECMPDBG_FILE_IS_COMPRESSED = DECMPDBG_CODE(5),/* 0x03120014 */
69 };
70
71 #define MAX_DECMPFS_XATTR_SIZE 3802
72
73 /*
74 * NOTE: decmpfs can only be used by thread-safe filesystems
75 */
76
77 #define DECMPFS_MAGIC 0x636d7066 /* cmpf */
78
79 #define DECMPFS_XATTR_NAME "com.apple.decmpfs" /* extended attribute to use for decmpfs */
80
81 /*
82 * This single field is to be interpreted differently depending on the
83 * corresponding item type.
84 * For regular files: it is a 64bits-encoded logical size
85 * For directories: it is a 64bits-encoded number of children (ie st_nlink - 2)
86 * For packages: it is 40bits encoded size and 24bits number of children at root
87 */
88 typedef struct __attribute__((packed)) {
89 uint64_t value;
90 } decmpfs_raw_item_size;
91
92 #define DECMPFS_PKG_SIZE_MASK 0x000000ffffffffffULL
93 #define DECMPFS_PKG_COUNT_MASK 0xffffff
94 #define DECMPFS_PKG_CHLD_COUNT_SHIFT 40
95
96 #define DECMPFS_PKG_SIZE(x) ((x).value & DECMPFS_PKG_SIZE_MASK)
97 #define DECMPFS_PKG_CHLD_COUNT(x) ((uint32_t)(((x).value >> DECMPFS_PKG_CHLD_COUNT_SHIFT) & DECMPFS_PKG_COUNT_MASK))
98 #define DECMPFS_PKG_VALUE_FROM_SIZE_COUNT(size, count) \
99 (((size) & DECMPFS_PKG_SIZE_MASK) | ((uint64_t)(count) << DECMPFS_PKG_CHLD_COUNT_SHIFT))
100
101 /* Dataless file or directory */
102 #define DATALESS_CMPFS_TYPE 0x80000001
103
104 /* Dataless package, with number of root children and total size encoded on disk */
105 #define DATALESS_PKG_CMPFS_TYPE 0x80000002
106
107
108 static inline bool
decmpfs_type_is_dataless(uint32_t cmp_type)109 decmpfs_type_is_dataless(uint32_t cmp_type)
110 {
111 return cmp_type == DATALESS_CMPFS_TYPE || cmp_type == DATALESS_PKG_CMPFS_TYPE;
112 }
113
114 typedef struct __attribute__((packed)) {
115 /* this structure represents the xattr on disk; the fields below are little-endian */
116 uint32_t compression_magic;
117 uint32_t compression_type; /* see the enum below */
118 union {
119 uint64_t uncompressed_size; /* compatility accessor */
120 decmpfs_raw_item_size _size;
121 };
122 unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
123 } decmpfs_disk_header;
124
125 typedef struct __attribute__((packed)) {
126 /* this structure represents the xattr in memory; the fields below are host-endian */
127 uint32_t attr_size;
128 uint32_t compression_magic;
129 uint32_t compression_type;
130 union {
131 /*
132 * although uncompressed_size remains available for backward-compatibility reasons
133 * the uncompressed size and nchildren should be accessed using the inline helpers
134 * below
135 */
136 uint64_t uncompressed_size;
137 decmpfs_raw_item_size _size;
138 };
139 unsigned char attr_bytes[0]; /* the bytes of the attribute after the header */
140 } decmpfs_header;
141
142 static inline uint64_t
decmpfs_get_uncompressed_size(const decmpfs_header * hdr)143 decmpfs_get_uncompressed_size(const decmpfs_header *hdr)
144 {
145 if (hdr->compression_magic == DECMPFS_MAGIC && hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
146 return DECMPFS_PKG_SIZE(hdr->_size);
147 }
148
149 return hdr->uncompressed_size;
150 }
151
152 static inline uint32_t
decmpfs_get_directory_entries(const decmpfs_header * hdr)153 decmpfs_get_directory_entries(const decmpfs_header *hdr)
154 {
155 if (hdr->compression_magic == DECMPFS_MAGIC && hdr->compression_type == DATALESS_PKG_CMPFS_TYPE) {
156 return DECMPFS_PKG_CHLD_COUNT(hdr->_size);
157 }
158
159 return (uint32_t)hdr->uncompressed_size;
160 }
161
162 /* compression_type values */
163 enum {
164 CMP_Type1 = 1,/* uncompressed data in xattr */
165
166 /* additional types defined in AppleFSCompression project */
167
168 CMP_MAX = 255/* Highest compression_type supported */
169 };
170
171 typedef struct {
172 void *buf;
173 user_ssize_t size;
174 } decmpfs_vector;
175
176 __END_DECLS
177
178 #ifdef KERNEL
179
180 #ifdef XNU_KERNEL_PRIVATE
181
182 #include <kern/locks.h>
183
184 __BEGIN_DECLS
185
186 struct decmpfs_cnode {
187 uint8_t cmp_state;
188 uint8_t cmp_minimal_xattr; /* if non-zero, this file's com.apple.decmpfs xattr contained only the minimal decmpfs_disk_header */
189 uint32_t cmp_type;
190 uint32_t lockcount;
191 void *lockowner; /* cnode's lock owner (if a thread is currently holding an exclusive lock) */
192 uint64_t uncompressed_size __attribute__((aligned(8)));
193 uint64_t nchildren __attribute__((aligned(8))); /* for dataless directories (incl. packages) */
194 uint64_t total_size __attribute__((aligned(8)));/* for dataless directories (incl. packages) */
195 uint64_t decompression_flags;
196 lck_rw_t compressed_data_lock;
197 };
198
199 __END_DECLS
200
201 #endif // XNU_KERNEL_PRIVATE
202
203 __BEGIN_DECLS
204
205 typedef struct decmpfs_cnode decmpfs_cnode;
206
207 /* return values from decmpfs_file_is_compressed */
208 enum {
209 FILE_TYPE_UNKNOWN = 0,
210 FILE_IS_NOT_COMPRESSED = 1,
211 FILE_IS_COMPRESSED = 2,
212 FILE_IS_CONVERTING = 3/* file is converting from compressed to decompressed */
213 };
214
215 /* vfs entrypoints */
216 extern vfs_context_t decmpfs_ctx;
217
218 /* client filesystem entrypoints */
219 void decmpfs_init(void);
220 decmpfs_cnode *decmpfs_cnode_alloc(void);
221 void decmpfs_cnode_free(decmpfs_cnode *dp);
222 void decmpfs_cnode_init(decmpfs_cnode *cp);
223 void decmpfs_cnode_destroy(decmpfs_cnode *cp);
224
225 int decmpfs_hides_rsrc(vfs_context_t ctx, decmpfs_cnode *cp);
226 int decmpfs_hides_xattr(vfs_context_t ctx, decmpfs_cnode *cp, const char *xattr);
227
228 bool decmpfs_trylock_compressed_data(decmpfs_cnode *cp, int exclusive);
229 void decmpfs_lock_compressed_data(decmpfs_cnode *cp, int exclusive);
230 void decmpfs_unlock_compressed_data(decmpfs_cnode *cp, int exclusive);
231
232 uint32_t decmpfs_cnode_get_vnode_state(decmpfs_cnode *cp);
233 void decmpfs_cnode_set_vnode_state(decmpfs_cnode *cp, uint32_t state, int skiplock);
234 uint64_t decmpfs_cnode_get_vnode_cached_size(decmpfs_cnode *cp);
235 uint64_t decmpfs_cnode_get_vnode_cached_nchildren(decmpfs_cnode *cp);
236 uint64_t decmpfs_cnode_get_vnode_cached_total_size(decmpfs_cnode *cp);
237 void decmpfs_cnode_set_vnode_cached_size(decmpfs_cnode *cp, uint64_t size);
238 void decmpfs_cnode_set_vnode_cached_nchildren(decmpfs_cnode *cp, uint64_t nchildren);
239 void decmpfs_cnode_set_vnode_cached_total_size(decmpfs_cnode *cp, uint64_t total_sz);
240 uint32_t decmpfs_cnode_cmp_type(decmpfs_cnode *cp);
241
242 int decmpfs_file_is_compressed(vnode_t vp, decmpfs_cnode *cp);
243 errno_t decmpfs_validate_compressed_file(vnode_t vp, decmpfs_cnode *cp);
244 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 */
245 int decmpfs_free_compressed_data(vnode_t vp, decmpfs_cnode *cp);
246 int decmpfs_update_attributes(vnode_t vp, struct vnode_attr *vap);
247 /* 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 */
248 errno_t decmpfs_pagein_compressed(struct vnop_pagein_args *ap, int *is_compressed, decmpfs_cnode *cp);
249 errno_t decmpfs_read_compressed(struct vnop_read_args *ap, int *is_compressed, decmpfs_cnode *cp);
250
251 /* types shared between the kernel and kexts */
252 typedef int (*decmpfs_validate_compressed_file_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
253 typedef void (*decmpfs_adjust_fetch_region_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr, off_t *offset, user_ssize_t *size);
254 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);
255 typedef int (*decmpfs_free_compressed_data_func)(vnode_t vp, vfs_context_t ctx, decmpfs_header *hdr);
256 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
257
258 enum {
259 DECMPFS_FLAGS_FORCE_FLUSH_ON_DECOMPRESS = 1 << 0,
260 };
261
262 /* Versions that are supported for binary compatibility */
263 #define DECMPFS_REGISTRATION_VERSION_V1 1
264 #define DECMPFS_REGISTRATION_VERSION_V3 3
265
266 #define DECMPFS_REGISTRATION_VERSION (DECMPFS_REGISTRATION_VERSION_V3)
267
268 typedef struct {
269 int decmpfs_registration;
270 decmpfs_validate_compressed_file_func validate;
271 decmpfs_adjust_fetch_region_func adjust_fetch;
272 decmpfs_fetch_uncompressed_data_func fetch;
273 decmpfs_free_compressed_data_func free_data;
274 decmpfs_get_decompression_flags_func get_flags;
275 } decmpfs_registration;
276
277 /* hooks for kexts to call */
278 errno_t register_decmpfs_decompressor(uint32_t compression_type, const decmpfs_registration *registration);
279 errno_t unregister_decmpfs_decompressor(uint32_t compression_type, decmpfs_registration *registration);
280
281 __END_DECLS
282 #endif /* KERNEL */
283
284 #endif /* _SYS_DECMPFS_H_ */
285