source: MondoRescue/branches/3.2/mindi-busybox/archival/libarchive/decompress_uncompress.c@ 3232

Last change on this file since 3232 was 3232, checked in by Bruno Cornec, 10 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 7.9 KB
Line 
1/* vi: set sw=4 ts=4: */
2/* uncompress for busybox -- (c) 2002 Robert Griebl
3 *
4 * based on the original compress42.c source
5 * (see disclaimer below)
6 */
7
8/* (N)compress42.c - File compression ala IEEE Computer, Mar 1992.
9 *
10 * Authors:
11 * Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
12 * Jim McKie (decvax!mcvax!jim)
13 * Steve Davies (decvax!vax135!petsd!peora!srd)
14 * Ken Turkowski (decvax!decwrl!turtlevax!ken)
15 * James A. Woods (decvax!ihnp4!ames!jaw)
16 * Joe Orost (decvax!vax135!petsd!joe)
17 * Dave Mack (csu@alembic.acs.com)
18 * Peter Jannesen, Network Communication Systems
19 * (peter@ncs.nl)
20 *
21 * marc@suse.de : a small security fix for a buffer overflow
22 *
23 * [... History snipped ...]
24 *
25 */
26
27#include "libbb.h"
28#include "bb_archive.h"
29
30
31/* Default input buffer size */
32#define IBUFSIZ 2048
33
34/* Default output buffer size */
35#define OBUFSIZ 2048
36
37/* Defines for third byte of header */
38#define BIT_MASK 0x1f /* Mask for 'number of compresssion bits' */
39 /* Masks 0x20 and 0x40 are free. */
40 /* I think 0x20 should mean that there is */
41 /* a fourth header byte (for expansion). */
42#define BLOCK_MODE 0x80 /* Block compression if table is full and */
43 /* compression rate is dropping flush tables */
44 /* the next two codes should not be changed lightly, as they must not */
45 /* lie within the contiguous general code space. */
46#define FIRST 257 /* first free entry */
47#define CLEAR 256 /* table clear output code */
48
49#define INIT_BITS 9 /* initial number of bits/code */
50
51
52/* machine variants which require cc -Dmachine: pdp11, z8000, DOS */
53#define HBITS 17 /* 50% occupancy */
54#define HSIZE (1<<HBITS)
55#define HMASK (HSIZE-1) /* unused */
56#define HPRIME 9941 /* unused */
57#define BITS 16
58#define BITS_STR "16"
59#undef MAXSEG_64K /* unused */
60#define MAXCODE(n) (1L << (n))
61
62#define htabof(i) htab[i]
63#define codetabof(i) codetab[i]
64#define tab_prefixof(i) codetabof(i)
65#define tab_suffixof(i) ((unsigned char *)(htab))[i]
66#define de_stack ((unsigned char *)&(htab[HSIZE-1]))
67#define clear_tab_prefixof() memset(codetab, 0, 256)
68
69/*
70 * Decompress stdin to stdout. This routine adapts to the codes in the
71 * file building the "string" table on-the-fly; requiring no table to
72 * be stored in the compressed file.
73 */
74
75IF_DESKTOP(long long) int FAST_FUNC
76unpack_Z_stream(transformer_aux_data_t *aux, int src_fd, int dst_fd)
77{
78 IF_DESKTOP(long long total_written = 0;)
79 IF_DESKTOP(long long) int retval = -1;
80 unsigned char *stackp;
81 int finchar;
82 long oldcode;
83 long incode;
84 int inbits;
85 int posbits;
86 int outpos;
87 int insize;
88 int bitmask;
89 long free_ent;
90 long maxcode;
91 long maxmaxcode;
92 int n_bits;
93 int rsize = 0;
94 unsigned char *inbuf; /* were eating insane amounts of stack - */
95 unsigned char *outbuf; /* bad for some embedded targets */
96 unsigned char *htab;
97 unsigned short *codetab;
98
99 /* Hmm, these were statics - why?! */
100 /* user settable max # bits/code */
101 int maxbits; /* = BITS; */
102 /* block compress mode -C compatible with 2.0 */
103 int block_mode; /* = BLOCK_MODE; */
104
105 if (check_signature16(aux, src_fd, COMPRESS_MAGIC))
106 return -1;
107
108 inbuf = xzalloc(IBUFSIZ + 64);
109 outbuf = xzalloc(OBUFSIZ + 2048);
110 htab = xzalloc(HSIZE); /* wasn't zeroed out before, maybe can xmalloc? */
111 codetab = xzalloc(HSIZE * sizeof(codetab[0]));
112
113 insize = 0;
114
115 /* xread isn't good here, we have to return - caller may want
116 * to do some cleanup (e.g. delete incomplete unpacked file etc) */
117 if (full_read(src_fd, inbuf, 1) != 1) {
118 bb_error_msg("short read");
119 goto err;
120 }
121
122 maxbits = inbuf[0] & BIT_MASK;
123 block_mode = inbuf[0] & BLOCK_MODE;
124 maxmaxcode = MAXCODE(maxbits);
125
126 if (maxbits > BITS) {
127 bb_error_msg("compressed with %d bits, can only handle "
128 BITS_STR" bits", maxbits);
129 goto err;
130 }
131
132 n_bits = INIT_BITS;
133 maxcode = MAXCODE(INIT_BITS) - 1;
134 bitmask = (1 << INIT_BITS) - 1;
135 oldcode = -1;
136 finchar = 0;
137 outpos = 0;
138 posbits = 0 << 3;
139
140 free_ent = ((block_mode) ? FIRST : 256);
141
142 /* As above, initialize the first 256 entries in the table. */
143 /*clear_tab_prefixof(); - done by xzalloc */
144
145 {
146 int i;
147 for (i = 255; i >= 0; --i)
148 tab_suffixof(i) = (unsigned char) i;
149 }
150
151 do {
152 resetbuf:
153 {
154 int i;
155 int e;
156 int o;
157
158 o = posbits >> 3;
159 e = insize - o;
160
161 for (i = 0; i < e; ++i)
162 inbuf[i] = inbuf[i + o];
163
164 insize = e;
165 posbits = 0;
166 }
167
168 if (insize < (int) (IBUFSIZ + 64) - IBUFSIZ) {
169 rsize = safe_read(src_fd, inbuf + insize, IBUFSIZ);
170 if (rsize < 0)
171 bb_error_msg_and_die(bb_msg_read_error);
172 insize += rsize;
173 }
174
175 inbits = ((rsize > 0) ? (insize - insize % n_bits) << 3 :
176 (insize << 3) - (n_bits - 1));
177
178 while (inbits > posbits) {
179 long code;
180
181 if (free_ent > maxcode) {
182 posbits =
183 ((posbits - 1) +
184 ((n_bits << 3) -
185 (posbits - 1 + (n_bits << 3)) % (n_bits << 3)));
186 ++n_bits;
187 if (n_bits == maxbits) {
188 maxcode = maxmaxcode;
189 } else {
190 maxcode = MAXCODE(n_bits) - 1;
191 }
192 bitmask = (1 << n_bits) - 1;
193 goto resetbuf;
194 }
195 {
196 unsigned char *p = &inbuf[posbits >> 3];
197 code = ((p[0]
198 | ((long) (p[1]) << 8)
199 | ((long) (p[2]) << 16)) >> (posbits & 0x7)) & bitmask;
200 }
201 posbits += n_bits;
202
203 if (oldcode == -1) {
204 if (code >= 256)
205 bb_error_msg_and_die("corrupted data"); /* %ld", code); */
206 oldcode = code;
207 finchar = (int) oldcode;
208 outbuf[outpos++] = (unsigned char) finchar;
209 continue;
210 }
211
212 if (code == CLEAR && block_mode) {
213 clear_tab_prefixof();
214 free_ent = FIRST - 1;
215 posbits =
216 ((posbits - 1) +
217 ((n_bits << 3) -
218 (posbits - 1 + (n_bits << 3)) % (n_bits << 3)));
219 n_bits = INIT_BITS;
220 maxcode = MAXCODE(INIT_BITS) - 1;
221 bitmask = (1 << INIT_BITS) - 1;
222 goto resetbuf;
223 }
224
225 incode = code;
226 stackp = de_stack;
227
228 /* Special case for KwKwK string. */
229 if (code >= free_ent) {
230 if (code > free_ent) {
231/*
232 unsigned char *p;
233
234 posbits -= n_bits;
235 p = &inbuf[posbits >> 3];
236 bb_error_msg
237 ("insize:%d posbits:%d inbuf:%02X %02X %02X %02X %02X (%d)",
238 insize, posbits, p[-1], p[0], p[1], p[2], p[3],
239 (posbits & 07));
240*/
241 bb_error_msg("corrupted data");
242 goto err;
243 }
244
245 *--stackp = (unsigned char) finchar;
246 code = oldcode;
247 }
248
249 /* Generate output characters in reverse order */
250 while (code >= 256) {
251 if (stackp <= &htabof(0))
252 bb_error_msg_and_die("corrupted data");
253 *--stackp = tab_suffixof(code);
254 code = tab_prefixof(code);
255 }
256
257 finchar = tab_suffixof(code);
258 *--stackp = (unsigned char) finchar;
259
260 /* And put them out in forward order */
261 {
262 int i;
263
264 i = de_stack - stackp;
265 if (outpos + i >= OBUFSIZ) {
266 do {
267 if (i > OBUFSIZ - outpos) {
268 i = OBUFSIZ - outpos;
269 }
270
271 if (i > 0) {
272 memcpy(outbuf + outpos, stackp, i);
273 outpos += i;
274 }
275
276 if (outpos >= OBUFSIZ) {
277 xwrite(dst_fd, outbuf, outpos);
278 IF_DESKTOP(total_written += outpos;)
279 outpos = 0;
280 }
281 stackp += i;
282 i = de_stack - stackp;
283 } while (i > 0);
284 } else {
285 memcpy(outbuf + outpos, stackp, i);
286 outpos += i;
287 }
288 }
289
290 /* Generate the new entry. */
291 if (free_ent < maxmaxcode) {
292 tab_prefixof(free_ent) = (unsigned short) oldcode;
293 tab_suffixof(free_ent) = (unsigned char) finchar;
294 free_ent++;
295 }
296
297 /* Remember previous code. */
298 oldcode = incode;
299 }
300
301 } while (rsize > 0);
302
303 if (outpos > 0) {
304 xwrite(dst_fd, outbuf, outpos);
305 IF_DESKTOP(total_written += outpos;)
306 }
307
308 retval = IF_DESKTOP(total_written) + 0;
309 err:
310 free(inbuf);
311 free(outbuf);
312 free(htab);
313 free(codetab);
314 return retval;
315}
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