inflate.c revision 3417
1/* 2 * Parts of this file are not covered by: 3 * ---------------------------------------------------------------------------- 4 * "THE BEER-WARE LICENSE" (Revision 42): 5 * <phk@login.dknet.dk> wrote this file. As long as you retain this notice you 6 * can do whatever you want with this stuff. If we meet some day, and you think 7 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 8 * ---------------------------------------------------------------------------- 9 * 10 * $Id: imgact_gzip.c,v 1.4 1994/10/04 06:51:42 phk Exp $ 11 * 12 * This module handles execution of a.out files which have been run through 13 * "gzip -9". 14 * 15 * For now you need to use exactly this command to compress the binaries: 16 * 17 * gzip -9 -v < /bin/sh > /tmp/sh 18 * 19 * TODO: 20 * text-segments should be made R/O after being filled 21 * is the vm-stuff safe ? 22 * should handle the entire header of gzip'ed stuff. 23 * inflate isn't quite reentrant yet... 24 * error-handling is a mess... 25 * so is the rest... 26 */ 27 28#include <sys/param.h> 29#include <sys/systm.h> 30#include <sys/resourcevar.h> 31#include <sys/exec.h> 32#include <sys/inflate.h> 33#include <sys/mman.h> 34#include <sys/malloc.h> 35#include <sys/imgact.h> 36#include <sys/imgact_aout.h> 37#include <sys/kernel.h> 38#include <sys/sysent.h> 39 40#include <vm/vm.h> 41#include <vm/vm_kern.h> 42 43/* Stuff to make inflate() work */ 44# define uch u_char 45# define ush u_short 46# define ulg u_long 47# define memzero(dest,len) bzero(dest,len) 48# define NOMEMCPY 49#define FPRINTF printf 50 51#define EOF -1 52#define CHECK_EOF 53static int 54NextByte(struct gzip *gz) 55{ 56 int error; 57 58 if(gz->idx >= gz->len) { 59 gz->where = __LINE__; 60 return EOF; 61 } 62 63 if((!gz->inbuf) || gz->idx >= (gz->offset+PAGE_SIZE)) { 64 if(gz->inbuf) { 65 error = vm_deallocate(kernel_map, 66 (vm_offset_t)gz->inbuf, PAGE_SIZE); 67 if(error) { 68 gz->where = __LINE__; 69 gz->error = error; 70 return EOF; 71 } 72 } 73 74 gz->offset += PAGE_SIZE; 75 76 error = vm_mmap(kernel_map, /* map */ 77 (vm_offset_t *)&gz->inbuf, /* address */ 78 PAGE_SIZE, /* size */ 79 VM_PROT_READ, /* protection */ 80 VM_PROT_READ, /* max protection */ 81 0, /* flags */ 82 (caddr_t)gz->ip->vnodep, /* vnode */ 83 gz->offset); /* offset */ 84 if(error) { 85 gz->where = __LINE__; 86 gz->error = error; 87 return EOF; 88 } 89 90 } 91 return gz->inbuf[(gz->idx++) - gz->offset]; 92} 93 94#define NEXTBYTE NextByte(gz) 95 96static int 97Flush(struct gzip *gz,u_long siz) 98{ 99 u_char *p = slide,*q; 100 int i; 101 102 /* First, find a a.out-header */ 103 if(gz->output < sizeof gz->a_out) { 104 q = (u_char*) &gz->a_out; 105 i = min(siz,sizeof gz->a_out - gz->output); 106 bcopy(p,q+gz->output,i); 107 gz->output += i; 108 p += i; 109 siz -= i; 110 if(gz->output == sizeof gz->a_out) { 111 i = do_aout_hdr(gz); 112 if (i == -1) { 113 gz->where = __LINE__; 114 gz->error = ENOEXEC; 115 return ENOEXEC; 116 } else if (i) { 117 gz->where = __LINE__; 118 gz->error = i; 119 return ENOEXEC; 120 } 121 if(gz->file_offset < sizeof gz->a_out) { 122 q = (u_char*) gz->virtual_offset + gz->output - gz->file_offset; 123 bcopy(&gz->a_out,q,sizeof gz->a_out - gz->file_offset); 124 } 125 } 126 } 127 /* Skip over zero-padded first PAGE if needed */ 128 if(gz->output < gz->file_offset && (gz->output+siz) > gz->file_offset) { 129 i = min(siz, gz->file_offset - gz->output); 130 gz->output += i; 131 p += i; 132 siz -= i; 133 } 134 if(gz->output >= gz->file_offset && gz->output < gz->file_end) { 135 i = min(siz, gz->file_end - gz->output); 136 q = (u_char*) gz->virtual_offset + gz->output - gz->file_offset; 137 bcopy(p,q,i); 138 gz->output += i; 139 p += i; 140 siz -= i; 141 } 142 gz->output += siz; 143 return 0; 144} 145 146#define FLUSH(x,y) {int foo = Flush(x,y); if (foo) return foo;} 147static 148void * 149myalloc(u_long size) 150{ 151 return malloc(size, M_GZIP, M_NOWAIT); 152} 153#define malloc myalloc 154 155static 156void 157myfree(void * ptr) 158{ 159 free(ptr,M_GZIP); 160} 161#define free myfree 162 163static const int qflag = 0; 164#define Trace(x) /* */ 165 166 167/* This came from unzip-5.12. I have changed it to pass a "gz" pointer 168 * around, thus hopefully making it re-entrant. Poul-Henningi 169 */ 170 171/* inflate.c -- put in the public domain by Mark Adler 172 version c14o, 23 August 1994 */ 173 174/* You can do whatever you like with this source file, though I would 175 prefer that if you modify it and redistribute it that you include 176 comments to that effect with your name and the date. Thank you. 177 178 History: 179 vers date who what 180 ---- --------- -------------- ------------------------------------ 181 a ~~ Feb 92 M. Adler used full (large, one-step) lookup table 182 b1 21 Mar 92 M. Adler first version with partial lookup tables 183 b2 21 Mar 92 M. Adler fixed bug in fixed-code blocks 184 b3 22 Mar 92 M. Adler sped up match copies, cleaned up some 185 b4 25 Mar 92 M. Adler added prototypes; removed window[] (now 186 is the responsibility of unzip.h--also 187 changed name to slide[]), so needs diffs 188 for unzip.c and unzip.h (this allows 189 compiling in the small model on MSDOS); 190 fixed cast of q in huft_build(); 191 b5 26 Mar 92 M. Adler got rid of unintended macro recursion. 192 b6 27 Mar 92 M. Adler got rid of nextbyte() routine. fixed 193 bug in inflate_fixed(). 194 c1 30 Mar 92 M. Adler removed lbits, dbits environment variables. 195 changed BMAX to 16 for explode. Removed 196 OUTB usage, and replaced it with flush()-- 197 this was a 20% speed improvement! Added 198 an explode.c (to replace unimplod.c) that 199 uses the huft routines here. Removed 200 register union. 201 c2 4 Apr 92 M. Adler fixed bug for file sizes a multiple of 32k. 202 c3 10 Apr 92 M. Adler reduced memory of code tables made by 203 huft_build significantly (factor of two to 204 three). 205 c4 15 Apr 92 M. Adler added NOMEMCPY do kill use of memcpy(). 206 worked around a Turbo C optimization bug. 207 c5 21 Apr 92 M. Adler added the WSIZE #define to allow reducing 208 the 32K window size for specialized 209 applications. 210 c6 31 May 92 M. Adler added some typecasts to eliminate warnings 211 c7 27 Jun 92 G. Roelofs added some more typecasts (444: MSC bug). 212 c8 5 Oct 92 J-l. Gailly added ifdef'd code to deal with PKZIP bug. 213 c9 9 Oct 92 M. Adler removed a memory error message (~line 416). 214 c10 17 Oct 92 G. Roelofs changed ULONG/UWORD/byte to ulg/ush/uch, 215 removed old inflate, renamed inflate_entry 216 to inflate, added Mark's fix to a comment. 217 c10.5 14 Dec 92 M. Adler fix up error messages for incomplete trees. 218 c11 2 Jan 93 M. Adler fixed bug in detection of incomplete 219 tables, and removed assumption that EOB is 220 the longest code (bad assumption). 221 c12 3 Jan 93 M. Adler make tables for fixed blocks only once. 222 c13 5 Jan 93 M. Adler allow all zero length codes (pkzip 2.04c 223 outputs one zero length code for an empty 224 distance tree). 225 c14 12 Mar 93 M. Adler made inflate.c standalone with the 226 introduction of inflate.h. 227 c14b 16 Jul 93 G. Roelofs added (unsigned) typecast to w at 470. 228 c14c 19 Jul 93 J. Bush changed v[N_MAX], l[288], ll[28x+3x] arrays 229 to static for Amiga. 230 c14d 13 Aug 93 J-l. Gailly de-complicatified Mark's c[*p++]++ thing. 231 c14e 8 Oct 93 G. Roelofs changed memset() to memzero(). 232 c14f 22 Oct 93 G. Roelofs renamed quietflg to qflag; made Trace() 233 conditional; added inflate_free(). 234 c14g 28 Oct 93 G. Roelofs changed l/(lx+1) macro to pointer (Cray bug) 235 c14h 7 Dec 93 C. Ghisler huft_build() optimizations. 236 c14i 9 Jan 94 A. Verheijen set fixed_t{d,l} to NULL after freeing; 237 G. Roelofs check NEXTBYTE macro for EOF. 238 c14j 23 Jan 94 G. Roelofs removed Ghisler "optimizations"; ifdef'd 239 EOF check. 240 c14k 27 Feb 94 G. Roelofs added some typecasts to avoid warnings. 241 c14l 9 Apr 94 G. Roelofs fixed split comments on preprocessor lines 242 to avoid bug in Encore compiler. 243 c14m 7 Jul 94 P. Kienitz modified to allow assembler version of 244 inflate_codes() (define ASM_INFLATECODES) 245 c14n 22 Jul 94 G. Roelofs changed fprintf to FPRINTF for DLL versions 246 c14o 23 Aug 94 C. Spieler added a newline to a debug statement; 247 G. Roelofs added another typecast to avoid MSC warning 248 */ 249 250 251/* 252 Inflate deflated (PKZIP's method 8 compressed) data. The compression 253 method searches for as much of the current string of bytes (up to a 254 length of 258) in the previous 32K bytes. If it doesn't find any 255 matches (of at least length 3), it codes the next byte. Otherwise, it 256 codes the length of the matched string and its distance backwards from 257 the current position. There is a single Huffman code that codes both 258 single bytes (called "literals") and match lengths. A second Huffman 259 code codes the distance information, which follows a length code. Each 260 length or distance code actually represents a base value and a number 261 of "extra" (sometimes zero) bits to get to add to the base value. At 262 the end of each deflated block is a special end-of-block (EOB) literal/ 263 length code. The decoding process is basically: get a literal/length 264 code; if EOB then done; if a literal, emit the decoded byte; if a 265 length then get the distance and emit the referred-to bytes from the 266 sliding window of previously emitted data. 267 268 There are (currently) three kinds of inflate blocks: stored, fixed, and 269 dynamic. The compressor outputs a chunk of data at a time and decides 270 which method to use on a chunk-by-chunk basis. A chunk might typically 271 be 32K to 64K, uncompressed. If the chunk is uncompressible, then the 272 "stored" method is used. In this case, the bytes are simply stored as 273 is, eight bits per byte, with none of the above coding. The bytes are 274 preceded by a count, since there is no longer an EOB code. 275 276 If the data is compressible, then either the fixed or dynamic methods 277 are used. In the dynamic method, the compressed data is preceded by 278 an encoding of the literal/length and distance Huffman codes that are 279 to be used to decode this block. The representation is itself Huffman 280 coded, and so is preceded by a description of that code. These code 281 descriptions take up a little space, and so for small blocks, there is 282 a predefined set of codes, called the fixed codes. The fixed method is 283 used if the block ends up smaller that way (usually for quite small 284 chunks); otherwise the dynamic method is used. In the latter case, the 285 codes are customized to the probabilities in the current block and so 286 can code it much better than the pre-determined fixed codes can. 287 288 The Huffman codes themselves are decoded using a mutli-level table 289 lookup, in order to maximize the speed of decoding plus the speed of 290 building the decoding tables. See the comments below that precede the 291 lbits and dbits tuning parameters. 292 */ 293 294 295/* 296 Notes beyond the 1.93a appnote.txt: 297 298 1. Distance pointers never point before the beginning of the output 299 stream. 300 2. Distance pointers can point back across blocks, up to 32k away. 301 3. There is an implied maximum of 7 bits for the bit length table and 302 15 bits for the actual data. 303 4. If only one code exists, then it is encoded using one bit. (Zero 304 would be more efficient, but perhaps a little confusing.) If two 305 codes exist, they are coded using one bit each (0 and 1). 306 5. There is no way of sending zero distance codes--a dummy must be 307 sent if there are none. (History: a pre 2.0 version of PKZIP would 308 store blocks with no distance codes, but this was discovered to be 309 too harsh a criterion.) Valid only for 1.93a. 2.04c does allow 310 zero distance codes, which is sent as one code of zero bits in 311 length. 312 6. There are up to 286 literal/length codes. Code 256 represents the 313 end-of-block. Note however that the static length tree defines 314 288 codes just to fill out the Huffman codes. Codes 286 and 287 315 cannot be used though, since there is no length base or extra bits 316 defined for them. Similarily, there are up to 30 distance codes. 317 However, static trees define 32 codes (all 5 bits) to fill out the 318 Huffman codes, but the last two had better not show up in the data. 319 7. Unzip can check dynamic Huffman blocks for complete code sets. 320 The exception is that a single code would not be complete (see #4). 321 8. The five bits following the block type is really the number of 322 literal codes sent minus 257. 323 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits 324 (1+6+6). Therefore, to output three times the length, you output 325 three codes (1+1+1), whereas to output four times the same length, 326 you only need two codes (1+3). Hmm. 327 10. In the tree reconstruction algorithm, Code = Code + Increment 328 only if BitLength(i) is not zero. (Pretty obvious.) 329 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) 330 12. Note: length code 284 can represent 227-258, but length code 285 331 really is 258. The last length deserves its own, short code 332 since it gets used a lot in very redundant files. The length 333 258 is special since 258 - 3 (the min match length) is 255. 334 13. The literal/length and distance code bit lengths are read as a 335 single stream of lengths. It is possible (and advantageous) for 336 a repeat code (16, 17, or 18) to go across the boundary between 337 the two sets of lengths. 338 */ 339 340 341#define PKZIP_BUG_WORKAROUND /* PKZIP 1.93a problem--live with it */ 342 343/* 344 inflate.h must supply the uch slide[WSIZE] array and the NEXTBYTE, 345 FLUSH() and memzero macros. If the window size is not 32K, it 346 should also define WSIZE. If INFMOD is defined, it can include 347 compiled functions to support the NEXTBYTE and/or FLUSH() macros. 348 There are defaults for NEXTBYTE and FLUSH() below for use as 349 examples of what those functions need to do. Normally, you would 350 also want FLUSH() to compute a crc on the data. inflate.h also 351 needs to provide these typedefs: 352 353 typedef unsigned char uch; 354 typedef unsigned short ush; 355 typedef unsigned long ulg; 356 357 This module uses the external functions malloc() and free() (and 358 probably memset() or bzero() in the memzero() macro). Their 359 prototypes are normally found in <string.h> and <stdlib.h>. 360 */ 361#define INFMOD /* tell inflate.h to include code to be compiled */ 362 363/* Huffman code lookup table entry--this entry is four bytes for machines 364 that have 16-bit pointers (e.g. PC's in the small or medium model). 365 Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16 366 means that v is a literal, 16 < e < 32 means that v is a pointer to 367 the next table, which codes e - 16 bits, and lastly e == 99 indicates 368 an unused code. If a code with e == 99 is looked up, this implies an 369 error in the data. */ 370struct huft { 371 uch e; /* number of extra bits or operation */ 372 uch b; /* number of bits in this code or subcode */ 373 union { 374 ush n; /* literal, length base, or distance base */ 375 struct huft *t; /* pointer to next level of table */ 376 } v; 377}; 378 379 380/* Function prototypes */ 381#ifndef OF 382# ifdef __STDC__ 383# define OF(a) a 384# else /* !__STDC__ */ 385# define OF(a) () 386# endif /* ?__STDC__ */ 387#endif 388static int huft_build OF((struct gzip *,unsigned *, unsigned, unsigned, const ush *, const ush *, 389 struct huft **, int *)); 390static int huft_free OF((struct gzip *,struct huft *)); 391static int inflate_codes OF((struct gzip *,struct huft *, struct huft *, int, int)); 392static int inflate_stored OF((struct gzip *)); 393static int inflate_fixed OF((struct gzip *)); 394static int inflate_dynamic OF((struct gzip *)); 395static int inflate_block OF((struct gzip *,int *)); 396static int inflate_free OF((struct gzip *)); 397 398 399/* The inflate algorithm uses a sliding 32K byte window on the uncompressed 400 stream to find repeated byte strings. This is implemented here as a 401 circular buffer. The index is updated simply by incrementing and then 402 and'ing with 0x7fff (32K-1). */ 403/* It is left to other modules to supply the 32K area. It is assumed 404 to be usable as if it were declared "uch slide[32768];" or as just 405 "uch *slide;" and then malloc'ed in the latter case. The definition 406 must be in unzip.h, included above. */ 407 408 409/* Tables for deflate from PKZIP's appnote.txt. */ 410static const unsigned border[] = { /* Order of the bit length code lengths */ 411 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; 412static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */ 413 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 414 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; 415 /* note: see note #13 above about the 258 in this list. */ 416static const ush cplext[] = { /* Extra bits for literal codes 257..285 */ 417 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 418 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */ 419static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */ 420 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 421 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 422 8193, 12289, 16385, 24577}; 423static const ush cpdext[] = { /* Extra bits for distance codes */ 424 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 425 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 426 12, 12, 13, 13}; 427 428/* And'ing with mask[n] masks the lower n bits */ 429const ush mask[] = { 430 0x0000, 431 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, 432 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff 433}; 434 435 436/* Macros for inflate() bit peeking and grabbing. 437 The usage is: 438 439 NEEDBITS(j) 440 x = b & mask[j]; 441 DUMPBITS(j) 442 443 where NEEDBITS makes sure that b has at least j bits in it, and 444 DUMPBITS removes the bits from b. The macros use the variable k 445 for the number of bits in b. Normally, b and k are register 446 variables for speed, and are initialized at the begining of a 447 routine that uses these macros from a global bit buffer and count. 448 449 In order to not ask for more bits than there are in the compressed 450 stream, the Huffman tables are constructed to only ask for just 451 enough bits to make up the end-of-block code (value 256). Then no 452 bytes need to be "returned" to the buffer at the end of the last 453 block. See the huft_build() routine. 454 */ 455 456/* !!! XXX !!! */ 457ulg bb; /* bit buffer */ 458unsigned bk; /* bits in bit buffer */ 459 460#ifndef CHECK_EOF 461# define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE)<<k;k+=8;}} 462#else 463# define NEEDBITS(n) {while(k<(n)){int c=NEXTBYTE;if(c==EOF)return 1;\ 464 b|=((ulg)c)<<k;k+=8;}} 465#endif /* Piet Plomp: change "return 1" to "break" */ 466 467#define DUMPBITS(n) {b>>=(n);k-=(n);} 468 469 470/* 471 Huffman code decoding is performed using a multi-level table lookup. 472 The fastest way to decode is to simply build a lookup table whose 473 size is determined by the longest code. However, the time it takes 474 to build this table can also be a factor if the data being decoded 475 is not very long. The most common codes are necessarily the 476 shortest codes, so those codes dominate the decoding time, and hence 477 the speed. The idea is you can have a shorter table that decodes the 478 shorter, more probable codes, and then point to subsidiary tables for 479 the longer codes. The time it costs to decode the longer codes is 480 then traded against the time it takes to make longer tables. 481 482 This results of this trade are in the variables lbits and dbits 483 below. lbits is the number of bits the first level table for literal/ 484 length codes can decode in one step, and dbits is the same thing for 485 the distance codes. Subsequent tables are also less than or equal to 486 those sizes. These values may be adjusted either when all of the 487 codes are shorter than that, in which case the longest code length in 488 bits is used, or when the shortest code is *longer* than the requested 489 table size, in which case the length of the shortest code in bits is 490 used. 491 492 There are two different values for the two tables, since they code a 493 different number of possibilities each. The literal/length table 494 codes 286 possible values, or in a flat code, a little over eight 495 bits. The distance table codes 30 possible values, or a little less 496 than five bits, flat. The optimum values for speed end up being 497 about one bit more than those, so lbits is 8+1 and dbits is 5+1. 498 The optimum values may differ though from machine to machine, and 499 possibly even between compilers. Your mileage may vary. 500 */ 501 502 503const int lbits = 9; /* bits in base literal/length lookup table */ 504const int dbits = 6; /* bits in base distance lookup table */ 505 506 507/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */ 508#define BMAX 16 /* maximum bit length of any code (16 for explode) */ 509#define N_MAX 288 /* maximum number of codes in any set */ 510 511/* !!! XXX !!! */ 512unsigned hufts; /* track memory usage */ 513 514 515static int huft_build(gz,b, n, s, d, e, t, m) 516struct gzip *gz; 517unsigned *b; /* code lengths in bits (all assumed <= BMAX) */ 518unsigned n; /* number of codes (assumed <= N_MAX) */ 519unsigned s; /* number of simple-valued codes (0..s-1) */ 520const ush *d; /* list of base values for non-simple codes */ 521const ush *e; /* list of extra bits for non-simple codes */ 522struct huft **t; /* result: starting table */ 523int *m; /* maximum lookup bits, returns actual */ 524/* Given a list of code lengths and a maximum table size, make a set of 525 tables to decode that set of codes. Return zero on success, one if 526 the given code set is incomplete (the tables are still built in this 527 case), two if the input is invalid (all zero length codes or an 528 oversubscribed set of lengths), and three if not enough memory. 529 The code with value 256 is special, and the tables are constructed 530 so that no bits beyond that code are fetched when that code is 531 decoded. */ 532{ 533 unsigned a; /* counter for codes of length k */ 534 unsigned c[BMAX+1]; /* bit length count table */ 535 unsigned el; /* length of EOB code (value 256) */ 536 unsigned f; /* i repeats in table every f entries */ 537 int g; /* maximum code length */ 538 int h; /* table level */ 539 register unsigned i; /* counter, current code */ 540 register unsigned j; /* counter */ 541 register int k; /* number of bits in current code */ 542 int lx[BMAX+1]; /* memory for l[-1..BMAX-1] */ 543 int *l = lx+1; /* stack of bits per table */ 544 register unsigned *p; /* pointer into c[], b[], or v[] */ 545 register struct huft *q; /* points to current table */ 546 struct huft r; /* table entry for structure assignment */ 547 struct huft *u[BMAX]; /* table stack */ 548 static unsigned v[N_MAX]; /* values in order of bit length */ 549 register int w; /* bits before this table == (l * h) */ 550 unsigned x[BMAX+1]; /* bit offsets, then code stack */ 551 unsigned *xp; /* pointer into x */ 552 int y; /* number of dummy codes added */ 553 unsigned z; /* number of entries in current table */ 554 555 556 /* Generate counts for each bit length */ 557 el = n > 256 ? b[256] : BMAX; /* set length of EOB code, if any */ 558 memzero((char *)c, sizeof(c)); 559 p = b; i = n; 560 do { 561 c[*p]++; p++; /* assume all entries <= BMAX */ 562 } while (--i); 563 if (c[0] == n) /* null input--all zero length codes */ 564 { 565 *t = (struct huft *)NULL; 566 *m = 0; 567 return 0; 568 } 569 570 571 /* Find minimum and maximum length, bound *m by those */ 572 for (j = 1; j <= BMAX; j++) 573 if (c[j]) 574 break; 575 k = j; /* minimum code length */ 576 if ((unsigned)*m < j) 577 *m = j; 578 for (i = BMAX; i; i--) 579 if (c[i]) 580 break; 581 g = i; /* maximum code length */ 582 if ((unsigned)*m > i) 583 *m = i; 584 585 586 /* Adjust last length count to fill out codes, if needed */ 587 for (y = 1 << j; j < i; j++, y <<= 1) 588 if ((y -= c[j]) < 0) 589 return 2; /* bad input: more codes than bits */ 590 if ((y -= c[i]) < 0) 591 return 2; 592 c[i] += y; 593 594 595 /* Generate starting offsets into the value table for each length */ 596 x[1] = j = 0; 597 p = c + 1; xp = x + 2; 598 while (--i) { /* note that i == g from above */ 599 *xp++ = (j += *p++); 600 } 601 602 603 /* Make a table of values in order of bit lengths */ 604 p = b; i = 0; 605 do { 606 if ((j = *p++) != 0) 607 v[x[j]++] = i; 608 } while (++i < n); 609 610 611 /* Generate the Huffman codes and for each, make the table entries */ 612 x[0] = i = 0; /* first Huffman code is zero */ 613 p = v; /* grab values in bit order */ 614 h = -1; /* no tables yet--level -1 */ 615 w = l[-1] = 0; /* no bits decoded yet */ 616 u[0] = (struct huft *)NULL; /* just to keep compilers happy */ 617 q = (struct huft *)NULL; /* ditto */ 618 z = 0; /* ditto */ 619 620 /* go through the bit lengths (k already is bits in shortest code) */ 621 for (; k <= g; k++) 622 { 623 a = c[k]; 624 while (a--) 625 { 626 /* here i is the Huffman code of length k bits for value *p */ 627 /* make tables up to required level */ 628 while (k > w + l[h]) 629 { 630 w += l[h++]; /* add bits already decoded */ 631 632 /* compute minimum size table less than or equal to *m bits */ 633 z = (z = g - w) > (unsigned)*m ? *m : z; /* upper limit */ 634 if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */ 635 { /* too few codes for k-w bit table */ 636 f -= a + 1; /* deduct codes from patterns left */ 637 xp = c + k; 638 while (++j < z) /* try smaller tables up to z bits */ 639 { 640 if ((f <<= 1) <= *++xp) 641 break; /* enough codes to use up j bits */ 642 f -= *xp; /* else deduct codes from patterns */ 643 } 644 } 645 if ((unsigned)w + j > el && (unsigned)w < el) 646 j = el - w; /* make EOB code end at table */ 647 z = 1 << j; /* table entries for j-bit table */ 648 l[h] = j; /* set table size in stack */ 649 650 /* allocate and link in new table */ 651 if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) == 652 (struct huft *)NULL) 653 { 654 if (h) 655 huft_free(gz,u[0]); 656 return 3; /* not enough memory */ 657 } 658 hufts += z + 1; /* track memory usage */ 659 *t = q + 1; /* link to list for huft_free() */ 660 *(t = &(q->v.t)) = (struct huft *)NULL; 661 u[h] = ++q; /* table starts after link */ 662 663 /* connect to last table, if there is one */ 664 if (h) 665 { 666 x[h] = i; /* save pattern for backing up */ 667 r.b = (uch)l[h-1]; /* bits to dump before this table */ 668 r.e = (uch)(16 + j); /* bits in this table */ 669 r.v.t = q; /* pointer to this table */ 670 j = (i & ((1 << w) - 1)) >> (w - l[h-1]); 671 u[h-1][j] = r; /* connect to last table */ 672 } 673 } 674 675 /* set up table entry in r */ 676 r.b = (uch)(k - w); 677 if (p >= v + n) 678 r.e = 99; /* out of values--invalid code */ 679 else if (*p < s) 680 { 681 r.e = (uch)(*p < 256 ? 16 : 15); /* 256 is end-of-block code */ 682 r.v.n = *p++; /* simple code is just the value */ 683 } 684 else 685 { 686 r.e = (uch)e[*p - s]; /* non-simple--look up in lists */ 687 r.v.n = d[*p++ - s]; 688 } 689 690 /* fill code-like entries with r */ 691 f = 1 << (k - w); 692 for (j = i >> w; j < z; j += f) 693 q[j] = r; 694 695 /* backwards increment the k-bit code i */ 696 for (j = 1 << (k - 1); i & j; j >>= 1) 697 i ^= j; 698 i ^= j; 699 700 /* backup over finished tables */ 701 while ((i & ((1 << w) - 1)) != x[h]) 702 w -= l[--h]; /* don't need to update q */ 703 } 704 } 705 706 707 /* return actual size of base table */ 708 *m = l[0]; 709 710 711 /* Return true (1) if we were given an incomplete table */ 712 return y != 0 && g != 1; 713} 714 715 716 717static int huft_free(gz,t) 718struct gzip *gz; 719struct huft *t; /* table to free */ 720/* Free the malloc'ed tables built by huft_build(), which makes a linked 721 list of the tables it made, with the links in a dummy first entry of 722 each table. */ 723{ 724 register struct huft *p, *q; 725 726 727 /* Go through linked list, freeing from the malloced (t[-1]) address. */ 728 p = t; 729 while (p != (struct huft *)NULL) 730 { 731 q = (--p)->v.t; 732 free(p); 733 p = q; 734 } 735 return 0; 736} 737 738 739 740#ifdef ASM_INFLATECODES 741# define inflate_codes(tl,td,bl,bd) flate_codes(tl,td,bl,bd,(uch *)slide) 742 int flate_codes OF((struct huft *, struct huft *, int, int, uch *)); 743 744#else 745 746static int inflate_codes(gz,tl, td, bl, bd) 747struct gzip *gz; 748struct huft *tl, *td; /* literal/length and distance decoder tables */ 749int bl, bd; /* number of bits decoded by tl[] and td[] */ 750/* inflate (decompress) the codes in a deflated (compressed) block. 751 Return an error code or zero if it all goes ok. */ 752{ 753 register unsigned e; /* table entry flag/number of extra bits */ 754 unsigned n, d; /* length and index for copy */ 755 unsigned w; /* current window position */ 756 struct huft *t; /* pointer to table entry */ 757 unsigned ml, md; /* masks for bl and bd bits */ 758 register ulg b; /* bit buffer */ 759 register unsigned k; /* number of bits in bit buffer */ 760 761 762 /* make local copies of globals */ 763 b = bb; /* initialize bit buffer */ 764 k = bk; 765 w = wp; /* initialize window position */ 766 767 768 /* inflate the coded data */ 769 ml = mask[bl]; /* precompute masks for speed */ 770 md = mask[bd]; 771 while (1) /* do until end of block */ 772 { 773 NEEDBITS((unsigned)bl) 774 if ((e = (t = tl + ((unsigned)b & ml))->e) > 16) 775 do { 776 if (e == 99) 777 return 1; 778 DUMPBITS(t->b) 779 e -= 16; 780 NEEDBITS(e) 781 } while ((e = (t = t->v.t + ((unsigned)b & mask[e]))->e) > 16); 782 DUMPBITS(t->b) 783 if (e == 16) /* then it's a literal */ 784 { 785 slide[w++] = (uch)t->v.n; 786 if (w == WSIZE) 787 { 788 FLUSH(gz,w); 789 w = 0; 790 } 791 } 792 else /* it's an EOB or a length */ 793 { 794 /* exit if end of block */ 795 if (e == 15) 796 break; 797 798 /* get length of block to copy */ 799 NEEDBITS(e) 800 n = t->v.n + ((unsigned)b & mask[e]); 801 DUMPBITS(e); 802 803 /* decode distance of block to copy */ 804 NEEDBITS((unsigned)bd) 805 if ((e = (t = td + ((unsigned)b & md))->e) > 16) 806 do { 807 if (e == 99) 808 return 1; 809 DUMPBITS(t->b) 810 e -= 16; 811 NEEDBITS(e) 812 } while ((e = (t = t->v.t + ((unsigned)b & mask[e]))->e) > 16); 813 DUMPBITS(t->b) 814 NEEDBITS(e) 815 d = w - t->v.n - ((unsigned)b & mask[e]); 816 DUMPBITS(e) 817 818 /* do the copy */ 819 do { 820 n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); 821#ifndef NOMEMCPY 822 if (w - d >= e) /* (this test assumes unsigned comparison) */ 823 { 824 memcpy(slide + w, slide + d, e); 825 w += e; 826 d += e; 827 } 828 else /* do it slow to avoid memcpy() overlap */ 829#endif /* !NOMEMCPY */ 830 do { 831 slide[w++] = slide[d++]; 832 } while (--e); 833 if (w == WSIZE) 834 { 835 FLUSH(gz,w); 836 w = 0; 837 } 838 } while (n); 839 } 840 } 841 842 843 /* restore the globals from the locals */ 844 wp = w; /* restore global window pointer */ 845 bb = b; /* restore global bit buffer */ 846 bk = k; 847 848 849 /* done */ 850 return 0; 851} 852 853#endif /* ASM_INFLATECODES */ 854 855 856 857static int inflate_stored(gz) 858struct gzip *gz; 859/* "decompress" an inflated type 0 (stored) block. */ 860{ 861 unsigned n; /* number of bytes in block */ 862 unsigned w; /* current window position */ 863 register ulg b; /* bit buffer */ 864 register unsigned k; /* number of bits in bit buffer */ 865 866 867 /* make local copies of globals */ 868 Trace((stderr, "\nstored block")); 869 b = bb; /* initialize bit buffer */ 870 k = bk; 871 w = wp; /* initialize window position */ 872 873 874 /* go to byte boundary */ 875 n = k & 7; 876 DUMPBITS(n); 877 878 879 /* get the length and its complement */ 880 NEEDBITS(16) 881 n = ((unsigned)b & 0xffff); 882 DUMPBITS(16) 883 NEEDBITS(16) 884 if (n != (unsigned)((~b) & 0xffff)) 885 return 1; /* error in compressed data */ 886 DUMPBITS(16) 887 888 889 /* read and output the compressed data */ 890 while (n--) 891 { 892 NEEDBITS(8) 893 slide[w++] = (uch)b; 894 if (w == WSIZE) 895 { 896 FLUSH(gz,w); 897 w = 0; 898 } 899 DUMPBITS(8) 900 } 901 902 903 /* restore the globals from the locals */ 904 wp = w; /* restore global window pointer */ 905 bb = b; /* restore global bit buffer */ 906 bk = k; 907 return 0; 908} 909 910 911/* Globals for literal tables (built once) */ 912/* !!! XXX !!! */ 913struct huft *fixed_tl = (struct huft *)NULL; 914struct huft *fixed_td; 915int fixed_bl, fixed_bd; 916 917static int inflate_fixed(gz) 918struct gzip *gz; 919/* decompress an inflated type 1 (fixed Huffman codes) block. We should 920 either replace this with a custom decoder, or at least precompute the 921 Huffman tables. */ 922{ 923 /* if first time, set up tables for fixed blocks */ 924 Trace((stderr, "\nliteral block")); 925 if (fixed_tl == (struct huft *)NULL) 926 { 927 int i; /* temporary variable */ 928 static unsigned l[288]; /* length list for huft_build */ 929 930 /* literal table */ 931 for (i = 0; i < 144; i++) 932 l[i] = 8; 933 for (; i < 256; i++) 934 l[i] = 9; 935 for (; i < 280; i++) 936 l[i] = 7; 937 for (; i < 288; i++) /* make a complete, but wrong code set */ 938 l[i] = 8; 939 fixed_bl = 7; 940 if ((i = huft_build(gz,l, 288, 257, cplens, cplext, 941 &fixed_tl, &fixed_bl)) != 0) 942 { 943 fixed_tl = (struct huft *)NULL; 944 return i; 945 } 946 947 /* distance table */ 948 for (i = 0; i < 30; i++) /* make an incomplete code set */ 949 l[i] = 5; 950 fixed_bd = 5; 951 if ((i = huft_build(gz,l, 30, 0, cpdist, cpdext, &fixed_td, &fixed_bd)) > 1) 952 { 953 huft_free(gz,fixed_tl); 954 fixed_tl = (struct huft *)NULL; 955 return i; 956 } 957 } 958 959 960 /* decompress until an end-of-block code */ 961 return inflate_codes(gz,fixed_tl, fixed_td, fixed_bl, fixed_bd) != 0; 962} 963 964 965 966static int inflate_dynamic(gz) 967struct gzip *gz; 968/* decompress an inflated type 2 (dynamic Huffman codes) block. */ 969{ 970 int i; /* temporary variables */ 971 unsigned j; 972 unsigned l; /* last length */ 973 unsigned m; /* mask for bit lengths table */ 974 unsigned n; /* number of lengths to get */ 975 struct huft *tl; /* literal/length code table */ 976 struct huft *td; /* distance code table */ 977 int bl; /* lookup bits for tl */ 978 int bd; /* lookup bits for td */ 979 unsigned nb; /* number of bit length codes */ 980 unsigned nl; /* number of literal/length codes */ 981 unsigned nd; /* number of distance codes */ 982#ifdef PKZIP_BUG_WORKAROUND 983 static unsigned ll[288+32]; /* literal/length and distance code lengths */ 984#else 985 static unsigned ll[286+30]; /* literal/length and distance code lengths */ 986#endif 987 register ulg b; /* bit buffer */ 988 register unsigned k; /* number of bits in bit buffer */ 989 990 991 /* make local bit buffer */ 992 Trace((stderr, "\ndynamic block")); 993 b = bb; 994 k = bk; 995 996 997 /* read in table lengths */ 998 NEEDBITS(5) 999 nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */ 1000 DUMPBITS(5) 1001 NEEDBITS(5) 1002 nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */ 1003 DUMPBITS(5) 1004 NEEDBITS(4) 1005 nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */ 1006 DUMPBITS(4) 1007#ifdef PKZIP_BUG_WORKAROUND 1008 if (nl > 288 || nd > 32) 1009#else 1010 if (nl > 286 || nd > 30) 1011#endif 1012 return 1; /* bad lengths */ 1013 1014 1015 /* read in bit-length-code lengths */ 1016 for (j = 0; j < nb; j++) 1017 { 1018 NEEDBITS(3) 1019 ll[border[j]] = (unsigned)b & 7; 1020 DUMPBITS(3) 1021 } 1022 for (; j < 19; j++) 1023 ll[border[j]] = 0; 1024 1025 1026 /* build decoding table for trees--single level, 7 bit lookup */ 1027 bl = 7; 1028 if ((i = huft_build(gz,ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) 1029 { 1030 if (i == 1) 1031 huft_free(gz,tl); 1032 return i; /* incomplete code set */ 1033 } 1034 1035 1036 /* read in literal and distance code lengths */ 1037 n = nl + nd; 1038 m = mask[bl]; 1039 i = l = 0; 1040 while ((unsigned)i < n) 1041 { 1042 NEEDBITS((unsigned)bl) 1043 j = (td = tl + ((unsigned)b & m))->b; 1044 DUMPBITS(j) 1045 j = td->v.n; 1046 if (j < 16) /* length of code in bits (0..15) */ 1047 ll[i++] = l = j; /* save last length in l */ 1048 else if (j == 16) /* repeat last length 3 to 6 times */ 1049 { 1050 NEEDBITS(2) 1051 j = 3 + ((unsigned)b & 3); 1052 DUMPBITS(2) 1053 if ((unsigned)i + j > n) 1054 return 1; 1055 while (j--) 1056 ll[i++] = l; 1057 } 1058 else if (j == 17) /* 3 to 10 zero length codes */ 1059 { 1060 NEEDBITS(3) 1061 j = 3 + ((unsigned)b & 7); 1062 DUMPBITS(3) 1063 if ((unsigned)i + j > n) 1064 return 1; 1065 while (j--) 1066 ll[i++] = 0; 1067 l = 0; 1068 } 1069 else /* j == 18: 11 to 138 zero length codes */ 1070 { 1071 NEEDBITS(7) 1072 j = 11 + ((unsigned)b & 0x7f); 1073 DUMPBITS(7) 1074 if ((unsigned)i + j > n) 1075 return 1; 1076 while (j--) 1077 ll[i++] = 0; 1078 l = 0; 1079 } 1080 } 1081 1082 1083 /* free decoding table for trees */ 1084 huft_free(gz,tl); 1085 1086 1087 /* restore the global bit buffer */ 1088 bb = b; 1089 bk = k; 1090 1091 1092 /* build the decoding tables for literal/length and distance codes */ 1093 bl = lbits; 1094 if ((i = huft_build(gz,ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) 1095 { 1096 if (i == 1 && !qflag) { 1097 FPRINTF( "(incomplete l-tree) "); 1098 huft_free(gz,tl); 1099 } 1100 return i; /* incomplete code set */ 1101 } 1102 bd = dbits; 1103 if ((i = huft_build(gz,ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) 1104 { 1105 if (i == 1 && !qflag) { 1106 FPRINTF( "(incomplete d-tree) "); 1107#ifdef PKZIP_BUG_WORKAROUND 1108 i = 0; 1109 } 1110#else 1111 huft_free(gz,td); 1112 } 1113 huft_free(gz,tl); 1114 return i; /* incomplete code set */ 1115#endif 1116 } 1117 1118 1119 /* decompress until an end-of-block code */ 1120 if (inflate_codes(gz,tl, td, bl, bd)) 1121 return 1; 1122 1123 1124 /* free the decoding tables, return */ 1125 huft_free(gz,tl); 1126 huft_free(gz,td); 1127 return 0; 1128} 1129 1130 1131 1132static int inflate_block(gz,e) 1133struct gzip *gz; 1134int *e; /* last block flag */ 1135/* decompress an inflated block */ 1136{ 1137 unsigned t; /* block type */ 1138 register ulg b; /* bit buffer */ 1139 register unsigned k; /* number of bits in bit buffer */ 1140 1141 1142 /* make local bit buffer */ 1143 b = bb; 1144 k = bk; 1145 1146 1147 /* read in last block bit */ 1148 NEEDBITS(1) 1149 *e = (int)b & 1; 1150 DUMPBITS(1) 1151 1152 1153 /* read in block type */ 1154 NEEDBITS(2) 1155 t = (unsigned)b & 3; 1156 DUMPBITS(2) 1157 1158 1159 /* restore the global bit buffer */ 1160 bb = b; 1161 bk = k; 1162 1163 1164 /* inflate that block type */ 1165 if (t == 2) 1166 return inflate_dynamic(gz); 1167 if (t == 0) 1168 return inflate_stored(gz); 1169 if (t == 1) 1170 return inflate_fixed(gz); 1171 1172 1173 /* bad block type */ 1174 return 2; 1175} 1176 1177 1178 1179int inflate(gz, glbl) 1180struct gzip *gz; 1181struct gz_global * glbl; 1182/* decompress an inflated entry */ 1183{ 1184 int e; /* last block flag */ 1185 int r; /* result code */ 1186 unsigned h; /* maximum struct huft's malloc'ed */ 1187 1188 1189 /* initialize window, bit buffer */ 1190 wp = 0; 1191 bk = 0; 1192 bb = 0; 1193 1194 1195 /* decompress until the last block */ 1196 h = 0; 1197 do { 1198 hufts = 0; 1199 if ((r = inflate_block(gz,&e)) != 0) 1200 return r; 1201 if (hufts > h) 1202 h = hufts; 1203 } while (!e); 1204 1205 1206 /* flush out slide */ 1207 FLUSH(gz,wp); 1208 1209 1210 /* return success */ 1211 Trace((stderr, "\n%u bytes in Huffman tables (%d/entry)\n", 1212 h * sizeof(struct huft), sizeof(struct huft))); 1213 return 0; 1214} 1215 1216 1217 1218static int inflate_free(gz) 1219struct gzip *gz; 1220{ 1221 if (fixed_tl != (struct huft *)NULL) 1222 { 1223 huft_free(gz,fixed_td); 1224 huft_free(gz,fixed_tl); 1225 fixed_td = fixed_tl = (struct huft *)NULL; 1226 } 1227 return 0; 1228} 1229