cread.c revision 1.5
1 /* $NetBSD: cread.c,v 1.5 2009/03/14 14:45:57 dsl 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 66 static 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 76 static 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 86 static int get_byte(struct sd *); 87 static unsigned long getLong(struct sd *); 88 static void check_header(struct sd *); 89 90 /* XXX - find suitable headerf ile for these: */ 91 void *zcalloc(void *, unsigned int, unsigned int); 92 void zcfree(void *, void *); 93 void zmemcpy(unsigned char *, unsigned char *, unsigned int); 94 95 96 /* 97 * compression utilities 98 */ 99 100 void * 101 zcalloc (opaque, items, size) 102 void *opaque; 103 unsigned items; 104 unsigned size; 105 { 106 return(malloc(items * size)); 107 } 108 109 void 110 zcfree (opaque, ptr) 111 void *opaque; 112 void *ptr; 113 { 114 free(ptr); 115 } 116 117 void 118 zmemcpy(dest, source, len) 119 unsigned char *dest; 120 unsigned char *source; 121 unsigned int len; 122 { 123 bcopy(source, dest, len); 124 } 125 126 static int 127 get_byte(s) 128 struct sd *s; 129 { 130 if (s->z_eof) 131 return (EOF); 132 133 if (s->stream.avail_in == 0) { 134 int got; 135 136 errno = 0; 137 got = cread(s->fd, s->inbuf, Z_BUFSIZE); 138 if (got <= 0) { 139 s->z_eof = 1; 140 if (errno) s->z_err = Z_ERRNO; 141 return EOF; 142 } 143 s->stream.avail_in = got; 144 s->stream.next_in = s->inbuf; 145 } 146 s->stream.avail_in--; 147 return *(s->stream.next_in)++; 148 } 149 150 static unsigned long 151 getLong (s) 152 struct sd *s; 153 { 154 unsigned long x = (unsigned long)get_byte(s); 155 int c; 156 157 x += ((unsigned long)get_byte(s)) << 8; 158 x += ((unsigned long)get_byte(s)) << 16; 159 c = get_byte(s); 160 if (c == EOF) 161 s->z_err = Z_DATA_ERROR; 162 x += ((unsigned long)c)<<24; 163 return x; 164 } 165 166 static void 167 check_header(s) 168 struct sd *s; 169 { 170 int method; /* method byte */ 171 int flags; /* flags byte */ 172 unsigned int len; 173 int c; 174 175 /* Check the gzip magic header */ 176 for (len = 0; len < 2; len++) { 177 c = get_byte(s); 178 if (c == gz_magic[len]) 179 continue; 180 if ((c == EOF) && (len == 0)) { 181 /* 182 * We must not change s->compressed if we are at EOF; 183 * we may have come to the end of a gzipped file and be 184 * check to see if another gzipped file is concatenated 185 * to this one. If one isn't, we still need to be able 186 * to lseek on this file as a compressed file. 187 */ 188 return; 189 } 190 s->compressed = 0; 191 if (c != EOF) { 192 s->stream.avail_in++; 193 s->stream.next_in--; 194 } 195 s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END; 196 return; 197 } 198 s->compressed = 1; 199 method = get_byte(s); 200 flags = get_byte(s); 201 if (method != Z_DEFLATED || (flags & RESERVED) != 0) { 202 s->z_err = Z_DATA_ERROR; 203 return; 204 } 205 206 /* Discard time, xflags and OS code: */ 207 for (len = 0; len < 6; len++) 208 (void)get_byte(s); 209 210 if ((flags & EXTRA_FIELD) != 0) { 211 /* skip the extra field */ 212 len = (unsigned int)get_byte(s); 213 len += ((unsigned int)get_byte(s)) << 8; 214 /* len is garbage if EOF but the loop below will quit anyway */ 215 while (len-- != 0 && get_byte(s) != EOF) /*void*/; 216 } 217 if ((flags & ORIG_NAME) != 0) { 218 /* skip the original file name */ 219 while ((c = get_byte(s)) != 0 && c != EOF) /*void*/; 220 } 221 if ((flags & COMMENT) != 0) { 222 /* skip the .gz file comment */ 223 while ((c = get_byte(s)) != 0 && c != EOF) /*void*/; 224 } 225 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ 226 for (len = 0; len < 2; len++) 227 (void)get_byte(s); 228 } 229 s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK; 230 } 231 232 /* 233 * new open(), close(), read(), lseek() 234 */ 235 236 int 237 copen(fname, mode) 238 const char *fname; 239 int mode; 240 { 241 int fd; 242 struct sd *s = 0; 243 244 if ( ((fd = open(fname, mode)) == -1) || (mode != O_RDONLY) ) 245 /* compression only for read */ 246 return(fd); 247 248 ss[fd] = s = malloc(sizeof(struct sd)); 249 if (s == 0) 250 goto errout; 251 bzero(s, sizeof(struct sd)); 252 253 if (inflateInit2(&(s->stream), -15) != Z_OK) 254 goto errout; 255 256 s->stream.next_in = s->inbuf = (unsigned char*)malloc(Z_BUFSIZE); 257 if (s->inbuf == 0) { 258 inflateEnd(&(s->stream)); 259 goto errout; 260 } 261 262 s->fd = fd; 263 check_header(s); /* skip the .gz header */ 264 return(fd); 265 266 errout: 267 if (s != 0) 268 free(s); 269 close(fd); 270 return (-1); 271 } 272 273 int 274 cclose(fd) 275 int fd; 276 { 277 struct sd *s; 278 279 s = ss[fd]; 280 281 inflateEnd(&(s->stream)); 282 283 free(s->inbuf); 284 free(s); 285 286 return (close(fd)); 287 } 288 289 size_t 290 cread(fd, buf, len) 291 int fd; 292 void *buf; 293 size_t len; 294 { 295 struct sd *s; 296 unsigned char *start = buf; /* starting point for crc computation */ 297 298 s = ss[fd]; 299 300 if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) 301 return (-1); 302 if (s->z_err == Z_STREAM_END) 303 return (0); /* EOF */ 304 305 s->stream.next_out = buf; 306 s->stream.avail_out = len; 307 308 while (s->stream.avail_out != 0) { 309 310 if (s->compressed == 0) { 311 /* Copy first the lookahead bytes: */ 312 unsigned int n = s->stream.avail_in; 313 if (n > s->stream.avail_out) 314 n = s->stream.avail_out; 315 if (n > 0) { 316 zmemcpy(s->stream.next_out, 317 s->stream.next_in, n); 318 s->stream.next_out += n; 319 s->stream.next_in += n; 320 s->stream.avail_out -= n; 321 s->stream.avail_in -= n; 322 } 323 if (s->stream.avail_out > 0) { 324 int got; 325 got = read(s->fd, s->stream.next_out, 326 s->stream.avail_out); 327 if (got == -1) 328 return (got); 329 s->stream.avail_out -= got; 330 } 331 return (int)(len - s->stream.avail_out); 332 } 333 334 if (s->stream.avail_in == 0 && !s->z_eof) { 335 int got; 336 errno = 0; 337 got = read(fd, s->inbuf, Z_BUFSIZE); 338 if (got <= 0) { 339 s->z_eof = 1; 340 if (errno) { 341 s->z_err = Z_ERRNO; 342 break; 343 } 344 } 345 s->stream.avail_in = got; 346 s->stream.next_in = s->inbuf; 347 } 348 349 s->z_err = inflate(&(s->stream), Z_NO_FLUSH); 350 351 if (s->z_err == Z_STREAM_END) { 352 /* Check CRC and original size */ 353 s->crc = crc32(s->crc, start, (unsigned int) 354 (s->stream.next_out - start)); 355 start = s->stream.next_out; 356 357 if (getLong(s) != s->crc || 358 getLong(s) != s->stream.total_out) { 359 360 s->z_err = Z_DATA_ERROR; 361 } else { 362 /* Check for concatenated .gz files: */ 363 check_header(s); 364 if (s->z_err == Z_OK) { 365 inflateReset(&(s->stream)); 366 s->crc = crc32(0L, Z_NULL, 0); 367 } 368 } 369 } 370 if (s->z_err != Z_OK || s->z_eof) 371 break; 372 } 373 374 s->crc = crc32(s->crc, start, 375 (unsigned int)(s->stream.next_out - start)); 376 377 return (int)(len - s->stream.avail_out); 378 } 379 380 off_t 381 clseek(fd, offset, where) 382 int fd; 383 off_t offset; 384 int where; 385 { 386 struct sd *s; 387 388 s = ss[fd]; 389 390 if(s->compressed == 0) { 391 off_t res = lseek(fd, offset, where); 392 if (res != (off_t)-1) { 393 /* make sure the lookahead buffer is invalid */ 394 s->stream.avail_in = 0; 395 } 396 return (res); 397 } 398 399 switch(where) { 400 case SEEK_CUR: 401 offset += s->stream.total_out; 402 case SEEK_SET: 403 /* if seek backwards, simply start from the beginning */ 404 if (offset < s->stream.total_out) { 405 off_t res; 406 void *sav_inbuf; 407 408 res = lseek(fd, 0, SEEK_SET); 409 if(res == (off_t)-1) 410 return(res); 411 /* ??? perhaps fallback to close / open */ 412 413 inflateEnd(&(s->stream)); 414 415 sav_inbuf = s->inbuf; /* don't allocate again */ 416 bzero(s, sizeof(struct sd)); /* this resets total_out to 0! */ 417 418 inflateInit2(&(s->stream), -15); 419 s->stream.next_in = s->inbuf = sav_inbuf; 420 421 s->fd = fd; 422 check_header(s); /* skip the .gz header */ 423 } 424 425 /* to seek forwards, throw away data */ 426 if (offset > s->stream.total_out) { 427 off_t toskip = offset - s->stream.total_out; 428 429 while (toskip > 0) { 430 #define DUMMYBUFSIZE 256 431 char dummybuf[DUMMYBUFSIZE]; 432 off_t len = toskip; 433 if (len > DUMMYBUFSIZE) len = DUMMYBUFSIZE; 434 if (cread(fd, dummybuf, len) != len) { 435 errno = EINVAL; 436 return ((off_t)-1); 437 } 438 toskip -= len; 439 } 440 } 441 #ifdef DEBUG 442 if (offset != s->stream.total_out) 443 panic("lseek compressed"); 444 #endif 445 return (offset); 446 case SEEK_END: 447 errno = EINVAL; 448 break; 449 default: 450 errno = EINVAL; 451 } 452 453 return((off_t)-1); 454 } 455
Indexes created Mon Sep 29 21:09:56 GMT 2025