1/* $NetBSD: cread.c,v 1.9 2009/03/18 17:06:43 cegger Exp $ */ 2 3/* 4 * Copyright (c) 1996 5 * Matthias Drochner. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 */ 28 29/* 30 * Support for compressed bootfiles (only read) 31 * 32 * - provides copen(), cclose(), cread(), clseek(). 33 * - compression parts stripped from zlib:gzio.c 34 * - copied from libsa with small modifications for my MiNT environment. 35 * Note that everything in the 'tostools' hierarchy is made to function 36 * in my local MiNT environment. 37 */ 38 39/* gzio.c -- IO on .gz files 40 * Copyright (C) 1995-1996 Jean-loup Gailly. 41 * For conditions of distribution and use, see copyright notice in zlib.h 42 */ 43 44#define _CREAD_C /* Turn of open/close/read redefines */ 45 46#include <unistd.h> 47#include <string.h> 48#include <memory.h> 49#include <fcntl.h> 50#include <errno.h> 51#include <zlib.h> 52#include <cread.h> 53 54#define __P(proto) proto 55#define SOPEN_MAX 1 56 57 58#define EOF (-1) /* needed by compression code */ 59 60#ifdef SAVE_MEMORY 61#define Z_BUFSIZE 1024 62#else 63#define Z_BUFSIZE 32*1024 64#endif 65 66static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */ 67 68/* gzip flag byte */ 69#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ 70#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ 71#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 72#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 73#define COMMENT 0x10 /* bit 4 set: file comment present */ 74#define RESERVED 0xE0 /* bits 5..7: reserved */ 75 76static struct sd { 77 z_stream stream; 78 int z_err; /* error code for last stream operation */ 79 int z_eof; /* set if end of input file */ 80 int fd; 81 unsigned char *inbuf; /* input buffer */ 82 unsigned long crc; /* crc32 of uncompressed data */ 83 int compressed; /* 1 if input file is a .gz file */ 84} *ss[SOPEN_MAX]; 85 86static int get_byte(struct sd *); 87static unsigned long getLong(struct sd *); 88static void check_header(struct sd *); 89 90/* XXX - find suitable headerf ile for these: */ 91void *zcalloc(void *, unsigned int, unsigned int); 92void zcfree(void *, void *); 93void zmemcpy(unsigned char *, unsigned char *, unsigned int); 94 95 96/* 97 * compression utilities 98 */ 99 100void * 101zcalloc (void *opaque, unsigned items, unsigned size) 102{ 103 return(malloc(items * size)); 104} 105 106void 107zcfree (void *opaque, void *ptr) 108{ 109 free(ptr); 110} 111 112void 113zmemcpy(unsigned char *dest, unsigned char *source, unsigned int len) 114{ 115 memcpy(dest, source, len); 116} 117 118static int 119get_byte(struct sd *s) 120{ 121 if (s->z_eof) 122 return (EOF); 123 124 if (s->stream.avail_in == 0) { 125 int got; 126 127 errno = 0; 128 got = cread(s->fd, s->inbuf, Z_BUFSIZE); 129 if (got <= 0) { 130 s->z_eof = 1; 131 if (errno) s->z_err = Z_ERRNO; 132 return EOF; 133 } 134 s->stream.avail_in = got; 135 s->stream.next_in = s->inbuf; 136 } 137 s->stream.avail_in--; 138 return *(s->stream.next_in)++; 139} 140 141static unsigned long 142getLong (struct sd *s) 143{ 144 unsigned long x = (unsigned long)get_byte(s); 145 int c; 146 147 x += ((unsigned long)get_byte(s)) << 8; 148 x += ((unsigned long)get_byte(s)) << 16; 149 c = get_byte(s); 150 if (c == EOF) 151 s->z_err = Z_DATA_ERROR; 152 x += ((unsigned long)c)<<24; 153 return x; 154} 155 156static void 157check_header(struct sd *s) 158{ 159 int method; /* method byte */ 160 int flags; /* flags byte */ 161 unsigned int len; 162 int c; 163 164 /* Check the gzip magic header */ 165 for (len = 0; len < 2; len++) { 166 c = get_byte(s); 167 if (c == gz_magic[len]) 168 continue; 169 if ((c == EOF) && (len == 0)) { 170 /* 171 * We must not change s->compressed if we are at EOF; 172 * we may have come to the end of a gzipped file and be 173 * check to see if another gzipped file is concatenated 174 * to this one. If one isn't, we still need to be able 175 * to lseek on this file as a compressed file. 176 */ 177 return; 178 } 179 s->compressed = 0; 180 if (c != EOF) { 181 s->stream.avail_in++; 182 s->stream.next_in--; 183 } 184 s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END; 185 return; 186 } 187 s->compressed = 1; 188 method = get_byte(s); 189 flags = get_byte(s); 190 if (method != Z_DEFLATED || (flags & RESERVED) != 0) { 191 s->z_err = Z_DATA_ERROR; 192 return; 193 } 194 195 /* Discard time, xflags and OS code: */ 196 for (len = 0; len < 6; len++) 197 (void)get_byte(s); 198 199 if ((flags & EXTRA_FIELD) != 0) { 200 /* skip the extra field */ 201 len = (unsigned int)get_byte(s); 202 len += ((unsigned int)get_byte(s)) << 8; 203 /* len is garbage if EOF but the loop below will quit anyway */ 204 while (len-- != 0 && get_byte(s) != EOF) /*void*/; 205 } 206 if ((flags & ORIG_NAME) != 0) { 207 /* skip the original file name */ 208 while ((c = get_byte(s)) != 0 && c != EOF) /*void*/; 209 } 210 if ((flags & COMMENT) != 0) { 211 /* skip the .gz file comment */ 212 while ((c = get_byte(s)) != 0 && c != EOF) /*void*/; 213 } 214 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ 215 for (len = 0; len < 2; len++) 216 (void)get_byte(s); 217 } 218 s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK; 219} 220 221/* 222 * new open(), close(), read(), lseek() 223 */ 224 225int 226copen(const char *fname, int mode) 227{ 228 int fd; 229 struct sd *s = 0; 230 231 if ( ((fd = open(fname, mode)) == -1) || (mode != O_RDONLY) ) 232 /* compression only for read */ 233 return(fd); 234 235 ss[fd] = s = malloc(sizeof(struct sd)); 236 if (s == 0) 237 goto errout; 238 memset(s, 0, sizeof(struct sd)); 239 240 if (inflateInit2(&(s->stream), -15) != Z_OK) 241 goto errout; 242 243 s->stream.next_in = s->inbuf = (unsigned char*)malloc(Z_BUFSIZE); 244 if (s->inbuf == 0) { 245 inflateEnd(&(s->stream)); 246 goto errout; 247 } 248 249 s->fd = fd; 250 check_header(s); /* skip the .gz header */ 251 return(fd); 252 253errout: 254 if (s != 0) 255 free(s); 256 close(fd); 257 return (-1); 258} 259 260int 261cclose(int fd) 262{ 263 struct sd *s; 264 265 s = ss[fd]; 266 267 inflateEnd(&(s->stream)); 268 269 free(s->inbuf); 270 free(s); 271 272 return (close(fd)); 273} 274 275size_t 276cread(int fd, void *buf, size_t len) 277{ 278 struct sd *s; 279 unsigned char *start = buf; /* starting point for crc computation */ 280 281 s = ss[fd]; 282 283 if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) 284 return (-1); 285 if (s->z_err == Z_STREAM_END) 286 return (0); /* EOF */ 287 288 s->stream.next_out = buf; 289 s->stream.avail_out = len; 290 291 while (s->stream.avail_out != 0) { 292 293 if (s->compressed == 0) { 294 /* Copy first the lookahead bytes: */ 295 unsigned int n = s->stream.avail_in; 296 if (n > s->stream.avail_out) 297 n = s->stream.avail_out; 298 if (n > 0) { 299 zmemcpy(s->stream.next_out, 300 s->stream.next_in, n); 301 s->stream.next_out += n; 302 s->stream.next_in += n; 303 s->stream.avail_out -= n; 304 s->stream.avail_in -= n; 305 } 306 if (s->stream.avail_out > 0) { 307 int got; 308 got = read(s->fd, s->stream.next_out, 309 s->stream.avail_out); 310 if (got == -1) 311 return (got); 312 s->stream.avail_out -= got; 313 } 314 return (int)(len - s->stream.avail_out); 315 } 316 317 if (s->stream.avail_in == 0 && !s->z_eof) { 318 int got; 319 errno = 0; 320 got = read(fd, s->inbuf, Z_BUFSIZE); 321 if (got <= 0) { 322 s->z_eof = 1; 323 if (errno) { 324 s->z_err = Z_ERRNO; 325 break; 326 } 327 } 328 s->stream.avail_in = got; 329 s->stream.next_in = s->inbuf; 330 } 331 332 s->z_err = inflate(&(s->stream), Z_NO_FLUSH); 333 334 if (s->z_err == Z_STREAM_END) { 335 /* Check CRC and original size */ 336 s->crc = crc32(s->crc, start, (unsigned int) 337 (s->stream.next_out - start)); 338 start = s->stream.next_out; 339 340 if (getLong(s) != s->crc || 341 getLong(s) != s->stream.total_out) { 342 343 s->z_err = Z_DATA_ERROR; 344 } else { 345 /* Check for concatenated .gz files: */ 346 check_header(s); 347 if (s->z_err == Z_OK) { 348 inflateReset(&(s->stream)); 349 s->crc = crc32(0L, Z_NULL, 0); 350 } 351 } 352 } 353 if (s->z_err != Z_OK || s->z_eof) 354 break; 355 } 356 357 s->crc = crc32(s->crc, start, 358 (unsigned int)(s->stream.next_out - start)); 359 360 return (int)(len - s->stream.avail_out); 361} 362 363off_t 364clseek(int fd, off_t offset, int where) 365{ 366 struct sd *s; 367 368 s = ss[fd]; 369 370 if(s->compressed == 0) { 371 off_t res = lseek(fd, offset, where); 372 if (res != (off_t)-1) { 373 /* make sure the lookahead buffer is invalid */ 374 s->stream.avail_in = 0; 375 } 376 return (res); 377 } 378 379 switch(where) { 380 case SEEK_CUR: 381 offset += s->stream.total_out; 382 case SEEK_SET: 383 /* if seek backwards, simply start from the beginning */ 384 if (offset < s->stream.total_out) { 385 off_t res; 386 void *sav_inbuf; 387 388 res = lseek(fd, 0, SEEK_SET); 389 if(res == (off_t)-1) 390 return(res); 391 /* ??? perhaps fallback to close / open */ 392 393 inflateEnd(&(s->stream)); 394 395 sav_inbuf = s->inbuf; /* don't allocate again */ 396 memset(s, 0, sizeof(struct sd)); /* this resets total_out to 0! */ 397 398 inflateInit2(&(s->stream), -15); 399 s->stream.next_in = s->inbuf = sav_inbuf; 400 401 s->fd = fd; 402 check_header(s); /* skip the .gz header */ 403 } 404 405 /* to seek forwards, throw away data */ 406 if (offset > s->stream.total_out) { 407 off_t toskip = offset - s->stream.total_out; 408 409 while (toskip > 0) { 410#define DUMMYBUFSIZE 256 411 char dummybuf[DUMMYBUFSIZE]; 412 off_t len = toskip; 413 if (len > DUMMYBUFSIZE) len = DUMMYBUFSIZE; 414 if (cread(fd, dummybuf, len) != len) { 415 errno = EINVAL; 416 return ((off_t)-1); 417 } 418 toskip -= len; 419 } 420 } 421#ifdef DEBUG 422 if (offset != s->stream.total_out) 423 panic("lseek compressed"); 424#endif 425 return (offset); 426 case SEEK_END: 427 errno = EINVAL; 428 break; 429 default: 430 errno = EINVAL; 431 } 432 433 return((off_t)-1); 434} 435