1 /* SPDX-License-Identifier: 0BSD */ <<
2 <<
3 /* 1 /*
4 * XZ decompressor 2 * XZ decompressor
5 * 3 *
6 * Authors: Lasse Collin <lasse.collin@tukaani 4 * Authors: Lasse Collin <lasse.collin@tukaani.org>
7 * Igor Pavlov <https://7-zip.org/> !! 5 * Igor Pavlov <http://7-zip.org/>
>> 6 *
>> 7 * This file has been put into the public domain.
>> 8 * You can do whatever you want with this file.
8 */ 9 */
9 10
10 #ifndef XZ_H 11 #ifndef XZ_H
11 #define XZ_H 12 #define XZ_H
12 13
13 #ifdef __KERNEL__ 14 #ifdef __KERNEL__
14 # include <linux/stddef.h> 15 # include <linux/stddef.h>
15 # include <linux/types.h> 16 # include <linux/types.h>
16 #else 17 #else
17 # include <stddef.h> 18 # include <stddef.h>
18 # include <stdint.h> 19 # include <stdint.h>
19 #endif 20 #endif
20 21
>> 22 /* In Linux, this is used to make extern functions static when needed. */
>> 23 #ifndef XZ_EXTERN
>> 24 # define XZ_EXTERN extern
>> 25 #endif
>> 26
21 /** 27 /**
22 * enum xz_mode - Operation mode 28 * enum xz_mode - Operation mode
23 * 29 *
24 * @XZ_SINGLE: Single-call mode. 30 * @XZ_SINGLE: Single-call mode. This uses less RAM than
25 * multi-call modes, !! 31 * than multi-call modes, because the LZMA2
26 * dictionary doesn't 32 * dictionary doesn't need to be allocated as
27 * part of the decode 33 * part of the decoder state. All required data
28 * structures are all 34 * structures are allocated at initialization,
29 * so xz_dec_run() ca 35 * so xz_dec_run() cannot return XZ_MEM_ERROR.
30 * @XZ_PREALLOC: Multi-call mode wi 36 * @XZ_PREALLOC: Multi-call mode with preallocated LZMA2
31 * dictionary buffer. 37 * dictionary buffer. All data structures are
32 * allocated at initi 38 * allocated at initialization, so xz_dec_run()
33 * cannot return XZ_M 39 * cannot return XZ_MEM_ERROR.
34 * @XZ_DYNALLOC: Multi-call mode. T 40 * @XZ_DYNALLOC: Multi-call mode. The LZMA2 dictionary is
35 * allocated once the 41 * allocated once the required size has been
36 * parsed from the st 42 * parsed from the stream headers. If the
37 * allocation fails, 43 * allocation fails, xz_dec_run() will return
38 * XZ_MEM_ERROR. 44 * XZ_MEM_ERROR.
39 * 45 *
40 * It is possible to enable support only for a 46 * It is possible to enable support only for a subset of the above
41 * modes at compile time by defining XZ_DEC_SI 47 * modes at compile time by defining XZ_DEC_SINGLE, XZ_DEC_PREALLOC,
42 * or XZ_DEC_DYNALLOC. The xz_dec kernel modul 48 * or XZ_DEC_DYNALLOC. The xz_dec kernel module is always compiled
43 * with support for all operation modes, but t 49 * with support for all operation modes, but the preboot code may
44 * be built with fewer features to minimize co 50 * be built with fewer features to minimize code size.
45 */ 51 */
46 enum xz_mode { 52 enum xz_mode {
47 XZ_SINGLE, 53 XZ_SINGLE,
48 XZ_PREALLOC, 54 XZ_PREALLOC,
49 XZ_DYNALLOC 55 XZ_DYNALLOC
50 }; 56 };
51 57
52 /** 58 /**
53 * enum xz_ret - Return codes 59 * enum xz_ret - Return codes
54 * @XZ_OK: Everything is OK s 60 * @XZ_OK: Everything is OK so far. More input or more
55 * output space is re 61 * output space is required to continue. This
56 * return code is pos 62 * return code is possible only in multi-call mode
57 * (XZ_PREALLOC or XZ 63 * (XZ_PREALLOC or XZ_DYNALLOC).
58 * @XZ_STREAM_END: Operation finished 64 * @XZ_STREAM_END: Operation finished successfully.
59 * @XZ_UNSUPPORTED_CHECK: Integrity check ty 65 * @XZ_UNSUPPORTED_CHECK: Integrity check type is not supported. Decoding
60 * is still possible 66 * is still possible in multi-call mode by simply
61 * calling xz_dec_run 67 * calling xz_dec_run() again.
62 * Note that this ret 68 * Note that this return value is used only if
63 * XZ_DEC_ANY_CHECK w 69 * XZ_DEC_ANY_CHECK was defined at build time,
64 * which is not used 70 * which is not used in the kernel. Unsupported
65 * check types return 71 * check types return XZ_OPTIONS_ERROR if
66 * XZ_DEC_ANY_CHECK w 72 * XZ_DEC_ANY_CHECK was not defined at build time.
67 * @XZ_MEM_ERROR: Allocating memory 73 * @XZ_MEM_ERROR: Allocating memory failed. This return code is
68 * possible only if t 74 * possible only if the decoder was initialized
69 * with XZ_DYNALLOC. 75 * with XZ_DYNALLOC. The amount of memory that was
70 * tried to be alloca 76 * tried to be allocated was no more than the
71 * dict_max argument 77 * dict_max argument given to xz_dec_init().
72 * @XZ_MEMLIMIT_ERROR: A bigger LZMA2 dic 78 * @XZ_MEMLIMIT_ERROR: A bigger LZMA2 dictionary would be needed than
73 * allowed by the dic 79 * allowed by the dict_max argument given to
74 * xz_dec_init(). Thi 80 * xz_dec_init(). This return value is possible
75 * only in multi-call 81 * only in multi-call mode (XZ_PREALLOC or
76 * XZ_DYNALLOC); the 82 * XZ_DYNALLOC); the single-call mode (XZ_SINGLE)
77 * ignores the dict_m 83 * ignores the dict_max argument.
78 * @XZ_FORMAT_ERROR: File format was no 84 * @XZ_FORMAT_ERROR: File format was not recognized (wrong magic
79 * bytes). 85 * bytes).
80 * @XZ_OPTIONS_ERROR: This implementatio 86 * @XZ_OPTIONS_ERROR: This implementation doesn't support the requested
81 * compression option 87 * compression options. In the decoder this means
82 * that the header CR 88 * that the header CRC32 matches, but the header
83 * itself specifies s 89 * itself specifies something that we don't support.
84 * @XZ_DATA_ERROR: Compressed data is 90 * @XZ_DATA_ERROR: Compressed data is corrupt.
85 * @XZ_BUF_ERROR: Cannot make any pr 91 * @XZ_BUF_ERROR: Cannot make any progress. Details are slightly
86 * different between 92 * different between multi-call and single-call
87 * mode; more informa 93 * mode; more information below.
88 * 94 *
89 * In multi-call mode, XZ_BUF_ERROR is returne 95 * In multi-call mode, XZ_BUF_ERROR is returned when two consecutive calls
90 * to XZ code cannot consume any input and can 96 * to XZ code cannot consume any input and cannot produce any new output.
91 * This happens when there is no new input ava 97 * This happens when there is no new input available, or the output buffer
92 * is full while at least one output byte is s 98 * is full while at least one output byte is still pending. Assuming your
93 * code is not buggy, you can get this error o 99 * code is not buggy, you can get this error only when decoding a compressed
94 * stream that is truncated or otherwise corru 100 * stream that is truncated or otherwise corrupt.
95 * 101 *
96 * In single-call mode, XZ_BUF_ERROR is return 102 * In single-call mode, XZ_BUF_ERROR is returned only when the output buffer
97 * is too small or the compressed input is cor 103 * is too small or the compressed input is corrupt in a way that makes the
98 * decoder produce more output than the caller 104 * decoder produce more output than the caller expected. When it is
99 * (relatively) clear that the compressed inpu 105 * (relatively) clear that the compressed input is truncated, XZ_DATA_ERROR
100 * is used instead of XZ_BUF_ERROR. 106 * is used instead of XZ_BUF_ERROR.
101 */ 107 */
102 enum xz_ret { 108 enum xz_ret {
103 XZ_OK, 109 XZ_OK,
104 XZ_STREAM_END, 110 XZ_STREAM_END,
105 XZ_UNSUPPORTED_CHECK, 111 XZ_UNSUPPORTED_CHECK,
106 XZ_MEM_ERROR, 112 XZ_MEM_ERROR,
107 XZ_MEMLIMIT_ERROR, 113 XZ_MEMLIMIT_ERROR,
108 XZ_FORMAT_ERROR, 114 XZ_FORMAT_ERROR,
109 XZ_OPTIONS_ERROR, 115 XZ_OPTIONS_ERROR,
110 XZ_DATA_ERROR, 116 XZ_DATA_ERROR,
111 XZ_BUF_ERROR 117 XZ_BUF_ERROR
112 }; 118 };
113 119
114 /** 120 /**
115 * struct xz_buf - Passing input and output bu 121 * struct xz_buf - Passing input and output buffers to XZ code
116 * @in: Beginning of the input buffer. 122 * @in: Beginning of the input buffer. This may be NULL if and only
117 * if in_pos is equal to in_size. 123 * if in_pos is equal to in_size.
118 * @in_pos: Current position in the input 124 * @in_pos: Current position in the input buffer. This must not exceed
119 * in_size. 125 * in_size.
120 * @in_size: Size of the input buffer 126 * @in_size: Size of the input buffer
121 * @out: Beginning of the output buffer 127 * @out: Beginning of the output buffer. This may be NULL if and only
122 * if out_pos is equal to out_siz 128 * if out_pos is equal to out_size.
123 * @out_pos: Current position in the output 129 * @out_pos: Current position in the output buffer. This must not exceed
124 * out_size. 130 * out_size.
125 * @out_size: Size of the output buffer 131 * @out_size: Size of the output buffer
126 * 132 *
127 * Only the contents of the output buffer from 133 * Only the contents of the output buffer from out[out_pos] onward, and
128 * the variables in_pos and out_pos are modifi 134 * the variables in_pos and out_pos are modified by the XZ code.
129 */ 135 */
130 struct xz_buf { 136 struct xz_buf {
131 const uint8_t *in; 137 const uint8_t *in;
132 size_t in_pos; 138 size_t in_pos;
133 size_t in_size; 139 size_t in_size;
134 140
135 uint8_t *out; 141 uint8_t *out;
136 size_t out_pos; 142 size_t out_pos;
137 size_t out_size; 143 size_t out_size;
138 }; 144 };
139 145
140 /* !! 146 /**
141 * struct xz_dec - Opaque type to hold the XZ 147 * struct xz_dec - Opaque type to hold the XZ decoder state
142 */ 148 */
143 struct xz_dec; 149 struct xz_dec;
144 150
145 /** 151 /**
146 * xz_dec_init() - Allocate and initialize a X 152 * xz_dec_init() - Allocate and initialize a XZ decoder state
147 * @mode: Operation mode 153 * @mode: Operation mode
148 * @dict_max: Maximum size of the LZMA2 dict 154 * @dict_max: Maximum size of the LZMA2 dictionary (history buffer) for
149 * multi-call decoding. This is i 155 * multi-call decoding. This is ignored in single-call mode
150 * (mode == XZ_SINGLE). LZMA2 dic 156 * (mode == XZ_SINGLE). LZMA2 dictionary is always 2^n bytes
151 * or 2^n + 2^(n-1) bytes (the la 157 * or 2^n + 2^(n-1) bytes (the latter sizes are less common
152 * in practice), so other values 158 * in practice), so other values for dict_max don't make sense.
153 * In the kernel, dictionary size 159 * In the kernel, dictionary sizes of 64 KiB, 128 KiB, 256 KiB,
154 * 512 KiB, and 1 MiB are probabl 160 * 512 KiB, and 1 MiB are probably the only reasonable values,
155 * except for kernel and initramf 161 * except for kernel and initramfs images where a bigger
156 * dictionary can be fine and use 162 * dictionary can be fine and useful.
157 * 163 *
158 * Single-call mode (XZ_SINGLE): xz_dec_run() 164 * Single-call mode (XZ_SINGLE): xz_dec_run() decodes the whole stream at
159 * once. The caller must provide enough output 165 * once. The caller must provide enough output space or the decoding will
160 * fail. The output space is used as the dicti 166 * fail. The output space is used as the dictionary buffer, which is why
161 * there is no need to allocate the dictionary 167 * there is no need to allocate the dictionary as part of the decoder's
162 * internal state. 168 * internal state.
163 * 169 *
164 * Because the output buffer is used as the wo 170 * Because the output buffer is used as the workspace, streams encoded using
165 * a big dictionary are not a problem in singl 171 * a big dictionary are not a problem in single-call mode. It is enough that
166 * the output buffer is big enough to hold the 172 * the output buffer is big enough to hold the actual uncompressed data; it
167 * can be smaller than the dictionary size sto 173 * can be smaller than the dictionary size stored in the stream headers.
168 * 174 *
169 * Multi-call mode with preallocated dictionar 175 * Multi-call mode with preallocated dictionary (XZ_PREALLOC): dict_max bytes
170 * of memory is preallocated for the LZMA2 dic 176 * of memory is preallocated for the LZMA2 dictionary. This way there is no
171 * risk that xz_dec_run() could run out of mem 177 * risk that xz_dec_run() could run out of memory, since xz_dec_run() will
172 * never allocate any memory. Instead, if the 178 * never allocate any memory. Instead, if the preallocated dictionary is too
173 * small for decoding the given input stream, 179 * small for decoding the given input stream, xz_dec_run() will return
174 * XZ_MEMLIMIT_ERROR. Thus, it is important to 180 * XZ_MEMLIMIT_ERROR. Thus, it is important to know what kind of data will be
175 * decoded to avoid allocating excessive amoun 181 * decoded to avoid allocating excessive amount of memory for the dictionary.
176 * 182 *
177 * Multi-call mode with dynamically allocated 183 * Multi-call mode with dynamically allocated dictionary (XZ_DYNALLOC):
178 * dict_max specifies the maximum allowed dict 184 * dict_max specifies the maximum allowed dictionary size that xz_dec_run()
179 * may allocate once it has parsed the diction 185 * may allocate once it has parsed the dictionary size from the stream
180 * headers. This way excessive allocations can 186 * headers. This way excessive allocations can be avoided while still
181 * limiting the maximum memory usage to a sane 187 * limiting the maximum memory usage to a sane value to prevent running the
182 * system out of memory when decompressing str 188 * system out of memory when decompressing streams from untrusted sources.
183 * 189 *
184 * On success, xz_dec_init() returns a pointer 190 * On success, xz_dec_init() returns a pointer to struct xz_dec, which is
185 * ready to be used with xz_dec_run(). If memo 191 * ready to be used with xz_dec_run(). If memory allocation fails,
186 * xz_dec_init() returns NULL. 192 * xz_dec_init() returns NULL.
187 */ 193 */
188 struct xz_dec *xz_dec_init(enum xz_mode mode, !! 194 XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max);
189 195
190 /** 196 /**
191 * xz_dec_run() - Run the XZ decoder 197 * xz_dec_run() - Run the XZ decoder
192 * @s: Decoder state allocated using 198 * @s: Decoder state allocated using xz_dec_init()
193 * @b: Input and output buffers 199 * @b: Input and output buffers
194 * 200 *
195 * The possible return values depend on build 201 * The possible return values depend on build options and operation mode.
196 * See enum xz_ret for details. 202 * See enum xz_ret for details.
197 * 203 *
198 * Note that if an error occurs in single-call 204 * Note that if an error occurs in single-call mode (return value is not
199 * XZ_STREAM_END), b->in_pos and b->out_pos ar 205 * XZ_STREAM_END), b->in_pos and b->out_pos are not modified and the
200 * contents of the output buffer from b->out[b 206 * contents of the output buffer from b->out[b->out_pos] onward are
201 * undefined. This is true even after XZ_BUF_E 207 * undefined. This is true even after XZ_BUF_ERROR, because with some filter
202 * chains, there may be a second pass over the 208 * chains, there may be a second pass over the output buffer, and this pass
203 * cannot be properly done if the output buffe 209 * cannot be properly done if the output buffer is truncated. Thus, you
204 * cannot give the single-call decoder a too s 210 * cannot give the single-call decoder a too small buffer and then expect to
205 * get that amount valid data from the beginni 211 * get that amount valid data from the beginning of the stream. You must use
206 * the multi-call decoder if you don't want to 212 * the multi-call decoder if you don't want to uncompress the whole stream.
207 */ 213 */
208 enum xz_ret xz_dec_run(struct xz_dec *s, struc !! 214 XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b);
209 215
210 /** 216 /**
211 * xz_dec_reset() - Reset an already allocated 217 * xz_dec_reset() - Reset an already allocated decoder state
212 * @s: Decoder state allocated using 218 * @s: Decoder state allocated using xz_dec_init()
213 * 219 *
214 * This function can be used to reset the mult 220 * This function can be used to reset the multi-call decoder state without
215 * freeing and reallocating memory with xz_dec 221 * freeing and reallocating memory with xz_dec_end() and xz_dec_init().
216 * 222 *
217 * In single-call mode, xz_dec_reset() is alwa 223 * In single-call mode, xz_dec_reset() is always called in the beginning of
218 * xz_dec_run(). Thus, explicit call to xz_dec 224 * xz_dec_run(). Thus, explicit call to xz_dec_reset() is useful only in
219 * multi-call mode. 225 * multi-call mode.
220 */ 226 */
221 void xz_dec_reset(struct xz_dec *s); !! 227 XZ_EXTERN void xz_dec_reset(struct xz_dec *s);
222 228
223 /** 229 /**
224 * xz_dec_end() - Free the memory allocated fo 230 * xz_dec_end() - Free the memory allocated for the decoder state
225 * @s: Decoder state allocated using 231 * @s: Decoder state allocated using xz_dec_init(). If s is NULL,
226 * this function does nothing. 232 * this function does nothing.
227 */ 233 */
228 void xz_dec_end(struct xz_dec *s); !! 234 XZ_EXTERN void xz_dec_end(struct xz_dec *s);
229 <<
230 /** <<
231 * DOC: MicroLZMA decompressor <<
232 * <<
233 * This MicroLZMA header format was created fo <<
234 * by others too. **In most cases one needs th <<
235 * <<
236 * The compressed format supported by this dec <<
237 * whose first byte (always 0x00) has been rep <<
238 * of the LZMA properties (lc/lp/pb) byte. For <<
239 * 3/0/2, the first byte is 0xA2. This way the <<
240 * Just like with LZMA2, lc + lp <= 4 must be <<
241 * marker must not be used. The unused values <<
242 */ <<
243 <<
244 /* <<
245 * struct xz_dec_microlzma - Opaque type to ho <<
246 */ <<
247 struct xz_dec_microlzma; <<
248 <<
249 /** <<
250 * xz_dec_microlzma_alloc() - Allocate memory <<
251 * @mode: XZ_SINGLE or XZ_PREALLOC <<
252 * @dict_size: LZMA dictionary size. This mus <<
253 * at most 3 GiB. <<
254 * <<
255 * In contrast to xz_dec_init(), this function <<
256 * and remembers the dictionary size. xz_dec_m <<
257 * before calling xz_dec_microlzma_run(). <<
258 * <<
259 * The amount of allocated memory is a little <<
260 * With XZ_PREALLOC also a dictionary buffer o <<
261 * <<
262 * On success, xz_dec_microlzma_alloc() return <<
263 * struct xz_dec_microlzma. If memory allocati <<
264 * dict_size is invalid, NULL is returned. <<
265 */ <<
266 struct xz_dec_microlzma *xz_dec_microlzma_allo <<
267 <<
268 <<
269 /** <<
270 * xz_dec_microlzma_reset() - Reset the MicroL <<
271 * @s: Decoder state allocated using <<
272 * @comp_size: Compressed size of the input s <<
273 * @uncomp_size: Uncompressed size of the inp <<
274 * than the real uncompressed siz <<
275 * be specified if uncomp_size_is <<
276 * uncomp_size can never be set t <<
277 * expected real uncompressed siz <<
278 * result in XZ_DATA_ERROR. <<
279 * @uncomp_size_is_exact: This is an int inst <<
280 * requiring stdbool.h. This shou <<
281 * When this is set to false, err <<
282 */ <<
283 void xz_dec_microlzma_reset(struct xz_dec_micr <<
284 uint32_t uncomp_si <<
285 <<
286 /** <<
287 * xz_dec_microlzma_run() - Run the MicroLZMA <<
288 * @s: Decoder state initialized usin <<
289 * @b: Input and output buffers <<
290 * <<
291 * This works similarly to xz_dec_run() with a <<
292 * Only the differences are documented here. <<
293 * <<
294 * The only possible return values are XZ_OK, <<
295 * XZ_DATA_ERROR. This function cannot return <<
296 * is possible due to lack of input data or ou <<
297 * keep returning XZ_OK. Thus, the calling cod <<
298 * will eventually provide input and output sp <<
299 * comp_size and uncomp_size arguments given t <<
300 * If the caller cannot do this (for example, <<
301 * or otherwise corrupt), the caller must dete <<
302 * avoid an infinite loop. <<
303 * <<
304 * If the compressed data seems to be corrupt, <<
305 * This can happen also when incorrect diction <<
306 * compressed sizes have been specified. <<
307 * <<
308 * With XZ_PREALLOC only: As an extra feature, <<
309 * uncompressed data. This way the caller does <<
310 * output buffer for the bytes that will be ig <<
311 * <<
312 * With XZ_SINGLE only: In contrast to xz_dec_ <<
313 * is also possible and thus XZ_SINGLE is actu <<
314 * After XZ_OK the bytes decoded so far may be <<
315 * It is possible to continue decoding but the <<
316 * MUST NOT be changed by the caller. Increasi <<
317 * allowed to make more output space available <<
318 * space for the whole uncompressed data on th <<
319 * may be changed normally like with XZ_PREALL <<
320 * provided from non-contiguous memory. <<
321 */ <<
322 enum xz_ret xz_dec_microlzma_run(struct xz_dec <<
323 <<
324 /** <<
325 * xz_dec_microlzma_end() - Free the memory al <<
326 * @s: Decoder state allocated using <<
327 * If s is NULL, this function do <<
328 */ <<
329 void xz_dec_microlzma_end(struct xz_dec_microl <<
330 235
331 /* 236 /*
332 * Standalone build (userspace build or in-ker 237 * Standalone build (userspace build or in-kernel build for boot time use)
333 * needs a CRC32 implementation. For normal in 238 * needs a CRC32 implementation. For normal in-kernel use, kernel's own
334 * CRC32 module is used instead, and users of 239 * CRC32 module is used instead, and users of this module don't need to
335 * care about the functions below. 240 * care about the functions below.
336 */ 241 */
337 #ifndef XZ_INTERNAL_CRC32 242 #ifndef XZ_INTERNAL_CRC32
338 # ifdef __KERNEL__ 243 # ifdef __KERNEL__
339 # define XZ_INTERNAL_CRC32 0 244 # define XZ_INTERNAL_CRC32 0
340 # else 245 # else
341 # define XZ_INTERNAL_CRC32 1 246 # define XZ_INTERNAL_CRC32 1
342 # endif 247 # endif
343 #endif 248 #endif
344 249
345 #if XZ_INTERNAL_CRC32 250 #if XZ_INTERNAL_CRC32
346 /* 251 /*
347 * This must be called before any other xz_* f 252 * This must be called before any other xz_* function to initialize
348 * the CRC32 lookup table. 253 * the CRC32 lookup table.
349 */ 254 */
350 void xz_crc32_init(void); !! 255 XZ_EXTERN void xz_crc32_init(void);
351 256
352 /* 257 /*
353 * Update CRC32 value using the polynomial fro 258 * Update CRC32 value using the polynomial from IEEE-802.3. To start a new
354 * calculation, the third argument must be zer 259 * calculation, the third argument must be zero. To continue the calculation,
355 * the previously returned value is passed as 260 * the previously returned value is passed as the third argument.
356 */ 261 */
357 uint32_t xz_crc32(const uint8_t *buf, size_t s !! 262 XZ_EXTERN uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc);
358 #endif 263 #endif
359 #endif 264 #endif
360 265
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