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