source: MondoRescue/branches/2.2.9/mindi-busybox/archival/libarchive/decompress_uncompress.c@ 2725

Last change on this file since 2725 was 2725, checked in by Bruno Cornec, 13 years ago
  • Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3
  • Property svn:eol-style set to native
File size: 7.7 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 "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(int fd_in, int fd_out)
77{
78 IF_DESKTOP(long long total_written = 0;)
79 IF_DESKTOP(long long) int retval = -1;
80 unsigned char *stackp;
81 long code;
82 int finchar;
83 long oldcode;
84 long incode;
85 int inbits;
86 int posbits;
87 int outpos;
88 int insize;
89 int bitmask;
90 long free_ent;
91 long maxcode;
92 long maxmaxcode;
93 int n_bits;
94 int rsize = 0;
95 unsigned char *inbuf; /* were eating insane amounts of stack - */
96 unsigned char *outbuf; /* bad for some embedded targets */
97 unsigned char *htab;
98 unsigned short *codetab;
99
100 /* Hmm, these were statics - why?! */
101 /* user settable max # bits/code */
102 int maxbits; /* = BITS; */
103 /* block compress mode -C compatible with 2.0 */
104 int block_mode; /* = BLOCK_MODE; */
105
106 inbuf = xzalloc(IBUFSIZ + 64);
107 outbuf = xzalloc(OBUFSIZ + 2048);
108 htab = xzalloc(HSIZE); /* wsn't zeroed out before, maybe can xmalloc? */
109 codetab = xzalloc(HSIZE * sizeof(codetab[0]));
110
111 insize = 0;
112
113 /* xread isn't good here, we have to return - caller may want
114 * to do some cleanup (e.g. delete incomplete unpacked file etc) */
115 if (full_read(fd_in, inbuf, 1) != 1) {
116 bb_error_msg("short read");
117 goto err;
118 }
119
120 maxbits = inbuf[0] & BIT_MASK;
121 block_mode = inbuf[0] & BLOCK_MODE;
122 maxmaxcode = MAXCODE(maxbits);
123
124 if (maxbits > BITS) {
125 bb_error_msg("compressed with %d bits, can only handle "
126 BITS_STR" bits", maxbits);
127 goto err;
128 }
129
130 n_bits = INIT_BITS;
131 maxcode = MAXCODE(INIT_BITS) - 1;
132 bitmask = (1 << INIT_BITS) - 1;
133 oldcode = -1;
134 finchar = 0;
135 outpos = 0;
136 posbits = 0 << 3;
137
138 free_ent = ((block_mode) ? FIRST : 256);
139
140 /* As above, initialize the first 256 entries in the table. */
141 /*clear_tab_prefixof(); - done by xzalloc */
142
143 for (code = 255; code >= 0; --code) {
144 tab_suffixof(code) = (unsigned char) code;
145 }
146
147 do {
148 resetbuf:
149 {
150 int i;
151 int e;
152 int o;
153
154 o = posbits >> 3;
155 e = insize - o;
156
157 for (i = 0; i < e; ++i)
158 inbuf[i] = inbuf[i + o];
159
160 insize = e;
161 posbits = 0;
162 }
163
164 if (insize < (int) (IBUFSIZ + 64) - IBUFSIZ) {
165 rsize = safe_read(fd_in, inbuf + insize, IBUFSIZ);
166//error check??
167 insize += rsize;
168 }
169
170 inbits = ((rsize > 0) ? (insize - insize % n_bits) << 3 :
171 (insize << 3) - (n_bits - 1));
172
173 while (inbits > posbits) {
174 if (free_ent > maxcode) {
175 posbits =
176 ((posbits - 1) +
177 ((n_bits << 3) -
178 (posbits - 1 + (n_bits << 3)) % (n_bits << 3)));
179 ++n_bits;
180 if (n_bits == maxbits) {
181 maxcode = maxmaxcode;
182 } else {
183 maxcode = MAXCODE(n_bits) - 1;
184 }
185 bitmask = (1 << n_bits) - 1;
186 goto resetbuf;
187 }
188 {
189 unsigned char *p = &inbuf[posbits >> 3];
190
191 code = ((((long) (p[0])) | ((long) (p[1]) << 8) |
192 ((long) (p[2]) << 16)) >> (posbits & 0x7)) & bitmask;
193 }
194 posbits += n_bits;
195
196
197 if (oldcode == -1) {
198 oldcode = code;
199 finchar = (int) oldcode;
200 outbuf[outpos++] = (unsigned char) finchar;
201 continue;
202 }
203
204 if (code == CLEAR && block_mode) {
205 clear_tab_prefixof();
206 free_ent = FIRST - 1;
207 posbits =
208 ((posbits - 1) +
209 ((n_bits << 3) -
210 (posbits - 1 + (n_bits << 3)) % (n_bits << 3)));
211 n_bits = INIT_BITS;
212 maxcode = MAXCODE(INIT_BITS) - 1;
213 bitmask = (1 << INIT_BITS) - 1;
214 goto resetbuf;
215 }
216
217 incode = code;
218 stackp = de_stack;
219
220 /* Special case for KwKwK string. */
221 if (code >= free_ent) {
222 if (code > free_ent) {
223 unsigned char *p;
224
225 posbits -= n_bits;
226 p = &inbuf[posbits >> 3];
227
228 bb_error_msg
229 ("insize:%d posbits:%d inbuf:%02X %02X %02X %02X %02X (%d)",
230 insize, posbits, p[-1], p[0], p[1], p[2], p[3],
231 (posbits & 07));
232 bb_error_msg("corrupted data");
233 goto err;
234 }
235
236 *--stackp = (unsigned char) finchar;
237 code = oldcode;
238 }
239
240 /* Generate output characters in reverse order */
241 while ((long) code >= (long) 256) {
242 *--stackp = tab_suffixof(code);
243 code = tab_prefixof(code);
244 }
245
246 finchar = tab_suffixof(code);
247 *--stackp = (unsigned char) finchar;
248
249 /* And put them out in forward order */
250 {
251 int i;
252
253 i = de_stack - stackp;
254 if (outpos + i >= OBUFSIZ) {
255 do {
256 if (i > OBUFSIZ - outpos) {
257 i = OBUFSIZ - outpos;
258 }
259
260 if (i > 0) {
261 memcpy(outbuf + outpos, stackp, i);
262 outpos += i;
263 }
264
265 if (outpos >= OBUFSIZ) {
266 full_write(fd_out, outbuf, outpos);
267//error check??
268 IF_DESKTOP(total_written += outpos;)
269 outpos = 0;
270 }
271 stackp += i;
272 i = de_stack - stackp;
273 } while (i > 0);
274 } else {
275 memcpy(outbuf + outpos, stackp, i);
276 outpos += i;
277 }
278 }
279
280 /* Generate the new entry. */
281 code = free_ent;
282 if (code < maxmaxcode) {
283 tab_prefixof(code) = (unsigned short) oldcode;
284 tab_suffixof(code) = (unsigned char) finchar;
285 free_ent = code + 1;
286 }
287
288 /* Remember previous code. */
289 oldcode = incode;
290 }
291
292 } while (rsize > 0);
293
294 if (outpos > 0) {
295 full_write(fd_out, outbuf, outpos);
296//error check??
297 IF_DESKTOP(total_written += outpos;)
298 }
299
300 retval = IF_DESKTOP(total_written) + 0;
301 err:
302 free(inbuf);
303 free(outbuf);
304 free(htab);
305 free(codetab);
306 return retval;
307}
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