1 /*-
2 * Copyright (c) 2003-2007 Tim Kientzle
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 /*
27 * This code borrows heavily from "compress" source code, which is
28 * protected by the following copyright. (Clause 3 dropped by request
29 * of the Regents.)
30 */
31
32 /*-
33 * Copyright (c) 1985, 1986, 1992, 1993
34 * The Regents of the University of California. All rights reserved.
35 *
36 * This code is derived from software contributed to Berkeley by
37 * Diomidis Spinellis and James A. Woods, derived from original
38 * work by Spencer Thomas and Joseph Orost.
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
48 * 4. Neither the name of the University nor the names of its contributors
49 * may be used to endorse or promote products derived from this software
50 * without specific prior written permission.
51 *
52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62 * SUCH DAMAGE.
63 */
64
65
66 #include "archive_platform.h"
67 __FBSDID("$FreeBSD: head/lib/libarchive/archive_read_support_compression_compress.c 201094 2009-12-28 02:29:21Z kientzle $");
68
69 #ifdef HAVE_ERRNO_H
70 #include <errno.h>
71 #endif
72 #ifdef HAVE_STDLIB_H
73 #include <stdlib.h>
74 #endif
75 #ifdef HAVE_STRING_H
76 #include <string.h>
77 #endif
78 #ifdef HAVE_UNISTD_H
79 #include <unistd.h>
80 #endif
81
82 #include "archive.h"
83 #include "archive_private.h"
84 #include "archive_read_private.h"
85
86 /*
87 * Because LZW decompression is pretty simple, I've just implemented
88 * the whole decompressor here (cribbing from "compress" source code,
89 * of course), rather than relying on an external library. I have
90 * made an effort to clarify and simplify the algorithm, so the
91 * names and structure here don't exactly match those used by compress.
92 */
93
94 struct private_data {
95 /* Input variables. */
96 const unsigned char *next_in;
97 size_t avail_in;
98 int bit_buffer;
99 int bits_avail;
100 size_t bytes_in_section;
101
102 /* Output variables. */
103 size_t out_block_size;
104 void *out_block;
105
106 /* Decompression status variables. */
107 int use_reset_code;
108 int end_of_stream; /* EOF status. */
109 int maxcode; /* Largest code. */
110 int maxcode_bits; /* Length of largest code. */
111 int section_end_code; /* When to increase bits. */
112 int bits; /* Current code length. */
113 int oldcode; /* Previous code. */
114 int finbyte; /* Last byte of prev code. */
115
116 /* Dictionary. */
117 int free_ent; /* Next dictionary entry. */
118 unsigned char suffix[65536];
119 uint16_t prefix[65536];
120
121 /*
122 * Scratch area for expanding dictionary entries. Note:
123 * "worst" case here comes from compressing /dev/zero: the
124 * last code in the dictionary will code a sequence of
125 * 65536-256 zero bytes. Thus, we need stack space to expand
126 * a 65280-byte dictionary entry. (Of course, 32640:1
127 * compression could also be considered the "best" case. ;-)
128 */
129 unsigned char *stackp;
130 unsigned char stack[65300];
131 };
132
133 static int compress_bidder_bid(struct archive_read_filter_bidder *, struct archive_read_filter *);
134 static int compress_bidder_init(struct archive_read_filter *);
135 static int compress_bidder_free(struct archive_read_filter_bidder *);
136
137 static ssize_t compress_filter_read(struct archive_read_filter *, const void **);
138 static int compress_filter_close(struct archive_read_filter *);
139
140 static int getbits(struct archive_read_filter *, int n);
141 static int next_code(struct archive_read_filter *);
142
143 int
archive_read_support_compression_compress(struct archive * _a)144 archive_read_support_compression_compress(struct archive *_a)
145 {
146 struct archive_read *a = (struct archive_read *)_a;
147 struct archive_read_filter_bidder *bidder = __archive_read_get_bidder(a);
148
149 if (bidder == NULL)
150 return (ARCHIVE_FATAL);
151
152 bidder->data = NULL;
153 bidder->bid = compress_bidder_bid;
154 bidder->init = compress_bidder_init;
155 bidder->options = NULL;
156 bidder->free = compress_bidder_free;
157 return (ARCHIVE_OK);
158 }
159
160 /*
161 * Test whether we can handle this data.
162 *
163 * This logic returns zero if any part of the signature fails. It
164 * also tries to Do The Right Thing if a very short buffer prevents us
165 * from verifying as much as we would like.
166 */
167 static int
compress_bidder_bid(struct archive_read_filter_bidder * self,struct archive_read_filter * filter)168 compress_bidder_bid(struct archive_read_filter_bidder *self,
169 struct archive_read_filter *filter)
170 {
171 const unsigned char *buffer;
172 ssize_t avail;
173 int bits_checked;
174
175 (void)self; /* UNUSED */
176
177 buffer = __archive_read_filter_ahead(filter, 2, &avail);
178
179 if (buffer == NULL)
180 return (0);
181
182 bits_checked = 0;
183 if (buffer[0] != 037) /* Verify first ID byte. */
184 return (0);
185 bits_checked += 8;
186
187 if (buffer[1] != 0235) /* Verify second ID byte. */
188 return (0);
189 bits_checked += 8;
190
191 /*
192 * TODO: Verify more.
193 */
194
195 return (bits_checked);
196 }
197
198 /*
199 * Setup the callbacks.
200 */
201 static int
compress_bidder_init(struct archive_read_filter * self)202 compress_bidder_init(struct archive_read_filter *self)
203 {
204 struct private_data *state;
205 static const size_t out_block_size = 64 * 1024;
206 void *out_block;
207 int code;
208
209 self->code = ARCHIVE_COMPRESSION_COMPRESS;
210 self->name = "compress (.Z)";
211
212 state = (struct private_data *)calloc(sizeof(*state), 1);
213 out_block = malloc(out_block_size);
214 if (state == NULL || out_block == NULL) {
215 free(out_block);
216 free(state);
217 archive_set_error(&self->archive->archive, ENOMEM,
218 "Can't allocate data for %s decompression",
219 self->name);
220 return (ARCHIVE_FATAL);
221 }
222
223 self->data = state;
224 state->out_block_size = out_block_size;
225 state->out_block = out_block;
226 self->read = compress_filter_read;
227 self->skip = NULL; /* not supported */
228 self->close = compress_filter_close;
229
230 /* XXX MOVE THE FOLLOWING OUT OF INIT() XXX */
231
232 (void)getbits(self, 8); /* Skip first signature byte. */
233 (void)getbits(self, 8); /* Skip second signature byte. */
234
235 code = getbits(self, 8);
236 state->maxcode_bits = code & 0x1f;
237 state->maxcode = (1 << state->maxcode_bits);
238 state->use_reset_code = code & 0x80;
239
240 /* Initialize decompressor. */
241 state->free_ent = 256;
242 state->stackp = state->stack;
243 if (state->use_reset_code)
244 state->free_ent++;
245 state->bits = 9;
246 state->section_end_code = (1<<state->bits) - 1;
247 state->oldcode = -1;
248 for (code = 255; code >= 0; code--) {
249 state->prefix[code] = 0;
250 state->suffix[code] = code;
251 }
252 next_code(self);
253
254 return (ARCHIVE_OK);
255 }
256
257 /*
258 * Return a block of data from the decompression buffer. Decompress more
259 * as necessary.
260 */
261 static ssize_t
compress_filter_read(struct archive_read_filter * self,const void ** pblock)262 compress_filter_read(struct archive_read_filter *self, const void **pblock)
263 {
264 struct private_data *state;
265 unsigned char *p, *start, *end;
266 int ret;
267
268 state = (struct private_data *)self->data;
269 if (state->end_of_stream) {
270 *pblock = NULL;
271 return (0);
272 }
273 p = start = (unsigned char *)state->out_block;
274 end = start + state->out_block_size;
275
276 while (p < end && !state->end_of_stream) {
277 if (state->stackp > state->stack) {
278 *p++ = *--state->stackp;
279 } else {
280 ret = next_code(self);
281 if (ret == -1)
282 state->end_of_stream = ret;
283 else if (ret != ARCHIVE_OK)
284 return (ret);
285 }
286 }
287
288 *pblock = start;
289 return (p - start);
290 }
291
292 /*
293 * Clean up the reader.
294 */
295 static int
compress_bidder_free(struct archive_read_filter_bidder * self)296 compress_bidder_free(struct archive_read_filter_bidder *self)
297 {
298 self->data = NULL;
299 return (ARCHIVE_OK);
300 }
301
302 /*
303 * Close and release the filter.
304 */
305 static int
compress_filter_close(struct archive_read_filter * self)306 compress_filter_close(struct archive_read_filter *self)
307 {
308 struct private_data *state = (struct private_data *)self->data;
309
310 free(state->out_block);
311 free(state);
312 return (ARCHIVE_OK);
313 }
314
315 /*
316 * Process the next code and fill the stack with the expansion
317 * of the code. Returns ARCHIVE_FATAL if there is a fatal I/O or
318 * format error, ARCHIVE_EOF if we hit end of data, ARCHIVE_OK otherwise.
319 */
320 static int
next_code(struct archive_read_filter * self)321 next_code(struct archive_read_filter *self)
322 {
323 struct private_data *state = (struct private_data *)self->data;
324 int code, newcode;
325
326 static int debug_buff[1024];
327 static unsigned debug_index;
328
329 code = newcode = getbits(self, state->bits);
330 if (code < 0)
331 return (code);
332
333 debug_buff[debug_index++] = code;
334 if (debug_index >= sizeof(debug_buff)/sizeof(debug_buff[0]))
335 debug_index = 0;
336
337 /* If it's a reset code, reset the dictionary. */
338 if ((code == 256) && state->use_reset_code) {
339 /*
340 * The original 'compress' implementation blocked its
341 * I/O in a manner that resulted in junk bytes being
342 * inserted after every reset. The next section skips
343 * this junk. (Yes, the number of *bytes* to skip is
344 * a function of the current *bit* length.)
345 */
346 int skip_bytes = state->bits -
347 (state->bytes_in_section % state->bits);
348 skip_bytes %= state->bits;
349 state->bits_avail = 0; /* Discard rest of this byte. */
350 while (skip_bytes-- > 0) {
351 code = getbits(self, 8);
352 if (code < 0)
353 return (code);
354 }
355 /* Now, actually do the reset. */
356 state->bytes_in_section = 0;
357 state->bits = 9;
358 state->section_end_code = (1 << state->bits) - 1;
359 state->free_ent = 257;
360 state->oldcode = -1;
361 return (next_code(self));
362 }
363
364 if (code > state->free_ent) {
365 /* An invalid code is a fatal error. */
366 archive_set_error(&(self->archive->archive), -1,
367 "Invalid compressed data");
368 return (ARCHIVE_FATAL);
369 }
370
371 /* Special case for KwKwK string. */
372 if (code >= state->free_ent) {
373 *state->stackp++ = state->finbyte;
374 code = state->oldcode;
375 }
376
377 /* Generate output characters in reverse order. */
378 while (code >= 256) {
379 *state->stackp++ = state->suffix[code];
380 code = state->prefix[code];
381 }
382 *state->stackp++ = state->finbyte = code;
383
384 /* Generate the new entry. */
385 code = state->free_ent;
386 if (code < state->maxcode && state->oldcode >= 0) {
387 state->prefix[code] = state->oldcode;
388 state->suffix[code] = state->finbyte;
389 ++state->free_ent;
390 }
391 if (state->free_ent > state->section_end_code) {
392 state->bits++;
393 state->bytes_in_section = 0;
394 if (state->bits == state->maxcode_bits)
395 state->section_end_code = state->maxcode;
396 else
397 state->section_end_code = (1 << state->bits) - 1;
398 }
399
400 /* Remember previous code. */
401 state->oldcode = newcode;
402 return (ARCHIVE_OK);
403 }
404
405 /*
406 * Return next 'n' bits from stream.
407 *
408 * -1 indicates end of available data.
409 */
410 static int
getbits(struct archive_read_filter * self,int n)411 getbits(struct archive_read_filter *self, int n)
412 {
413 struct private_data *state = (struct private_data *)self->data;
414 int code;
415 ssize_t ret;
416 static const int mask[] = {
417 0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff,
418 0x1ff, 0x3ff, 0x7ff, 0xfff, 0x1fff, 0x3fff, 0x7fff, 0xffff
419 };
420
421 while (state->bits_avail < n) {
422 if (state->avail_in <= 0) {
423 state->next_in
424 = __archive_read_filter_ahead(self->upstream,
425 1, &ret);
426 if (ret == 0)
427 return (-1);
428 if (ret < 0 || state->next_in == NULL)
429 return (ARCHIVE_FATAL);
430 state->avail_in = ret;
431 __archive_read_filter_consume(self->upstream, ret);
432 }
433 state->bit_buffer |= *state->next_in++ << state->bits_avail;
434 state->avail_in--;
435 state->bits_avail += 8;
436 state->bytes_in_section++;
437 }
438
439 code = state->bit_buffer;
440 state->bit_buffer >>= n;
441 state->bits_avail -= n;
442
443 return (code & mask[n]);
444 }
445