cread.c revision 1.26.6.2
1 /* $NetBSD: cread.c,v 1.26.6.2 2016/03/19 11:30:31 skrll 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 * - replaces open(), close(), read(), lseek(). 33 * - original libsa open(), close(), read(), lseek() are called 34 * as oopen(), oclose(), oread() resp. olseek(). 35 * - compression parts stripped from zlib:gzio.c 36 */ 37 38 /* gzio.c -- IO on .gz files 39 * Copyright (C) 1995-1996 Jean-loup Gailly. 40 * For conditions of distribution and use, see copyright notice in zlib.h 41 */ 42 43 #include "stand.h" 44 #ifdef _STANDALONE 45 #include <lib/libkern/libkern.h> 46 #include <lib/libz/libz.h> 47 #else 48 #include <string.h> 49 #include <zlib.h> 50 #endif 51 52 #define EOF (-1) /* needed by compression code */ 53 54 #ifdef SAVE_MEMORY 55 #define Z_BUFSIZE 1024 56 #else 57 #define Z_BUFSIZE 4096 58 #endif 59 60 static const int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */ 61 62 /* gzip flag byte */ 63 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ 64 #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ 65 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 66 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 67 #define COMMENT 0x10 /* bit 4 set: file comment present */ 68 #define RESERVED 0xE0 /* bits 5..7: reserved */ 69 70 static struct sd { 71 z_stream stream; 72 int z_err; /* error code for last stream operation */ 73 int z_eof; /* set if end of input file */ 74 int fd; 75 unsigned char *inbuf; /* input buffer */ 76 unsigned long crc; /* crc32 of uncompressed data */ 77 int compressed; /* 1 if input file is a .gz file */ 78 } *ss[SOPEN_MAX]; 79 80 static int get_byte(struct sd *); 81 static unsigned long getLong(struct sd *); 82 static void check_header(struct sd *); 83 84 /* XXX - find suitable header file for these: */ 85 void *zcalloc(void *, unsigned int, unsigned int); 86 void zcfree(void *, void *); 87 void zmemcpy(unsigned char *, unsigned char *, unsigned int); 88 89 /* 90 * This is the double-loop version of LE CRC32 from if_ethersubr, 91 * lightly modified -- it is ~1KB smaller than libkern version with 92 * DYNAMIC_CRC_TABLE but too much slower especially on ancient poor CPUs. 93 */ 94 #ifndef ETHER_CRC_POLY_LE 95 #define ETHER_CRC_POLY_LE 0xedb88320 96 #endif 97 uint32_t 98 crc32(uint32_t crc, const uint8_t *const buf, size_t len) 99 { 100 #if defined(LIBSA_CREAD_NOCRC) 101 /* XXX provide a stub to avoid pulling a larger libkern version */ 102 return crc; 103 #else 104 uint32_t c, carry; 105 size_t i, j; 106 107 crc = 0xffffffffU ^ crc; 108 for (i = 0; i < len; i++) { 109 c = buf[i]; 110 for (j = 0; j < 8; j++) { 111 carry = ((crc & 0x01) ? 1 : 0) ^ (c & 0x01); 112 crc >>= 1; 113 c >>= 1; 114 if (carry) { 115 crc = (crc ^ ETHER_CRC_POLY_LE); 116 } 117 } 118 } 119 return (crc ^ 0xffffffffU); 120 #endif /* defined(LIBSA_CREAD_NOCRC) */ 121 } 122 123 /* 124 * compression utilities 125 */ 126 127 void * 128 zcalloc(void *opaque, unsigned int items, unsigned int size) 129 { 130 131 return alloc(items * size); 132 } 133 134 void 135 zcfree(void *opaque, void *ptr) 136 { 137 138 dealloc(ptr, 0); /* XXX works only with modified allocator */ 139 } 140 141 void 142 zmemcpy(unsigned char *dest, unsigned char *source, unsigned int len) 143 { 144 145 memcpy(dest, source, len); 146 } 147 148 static int 149 get_byte(struct sd *s) 150 { 151 if (s->z_eof) 152 return EOF; 153 154 if (s->stream.avail_in == 0) { 155 int got; 156 157 errno = 0; 158 got = oread(s->fd, s->inbuf, Z_BUFSIZE); 159 if (got <= 0) { 160 s->z_eof = 1; 161 if (errno) 162 s->z_err = Z_ERRNO; 163 return EOF; 164 } 165 s->stream.avail_in = got; 166 s->stream.next_in = s->inbuf; 167 } 168 s->stream.avail_in--; 169 return *(s->stream.next_in)++; 170 } 171 172 static unsigned long 173 getLong(struct sd *s) 174 { 175 unsigned long x; 176 int c; 177 178 x = (unsigned long)get_byte(s); 179 x += ((unsigned long)get_byte(s)) << 8; 180 x += ((unsigned long)get_byte(s)) << 16; 181 c = get_byte(s); 182 if (c == EOF) 183 s->z_err = Z_DATA_ERROR; 184 x += ((unsigned long)c) << 24; 185 return x; 186 } 187 188 static void 189 check_header(struct sd *s) 190 { 191 int method; /* method byte */ 192 int flags; /* flags byte */ 193 unsigned int len; 194 int c; 195 196 /* Check the gzip magic header */ 197 for (len = 0; len < 2; len++) { 198 c = get_byte(s); 199 if (c == gz_magic[len]) 200 continue; 201 if ((c == EOF) && (len == 0)) { 202 /* 203 * We must not change s->compressed if we are at EOF; 204 * we may have come to the end of a gzipped file and be 205 * check to see if another gzipped file is concatenated 206 * to this one. If one isn't, we still need to be able 207 * to lseek on this file as a compressed file. 208 */ 209 return; 210 } 211 s->compressed = 0; 212 if (c != EOF) { 213 s->stream.avail_in++; 214 s->stream.next_in--; 215 } 216 s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END; 217 return; 218 } 219 s->compressed = 1; 220 method = get_byte(s); 221 flags = get_byte(s); 222 if (method != Z_DEFLATED || (flags & RESERVED) != 0) { 223 s->z_err = Z_DATA_ERROR; 224 return; 225 } 226 227 /* Discard time, xflags and OS code: */ 228 for (len = 0; len < 6; len++) 229 (void)get_byte(s); 230 231 if ((flags & EXTRA_FIELD) != 0) { 232 /* skip the extra field */ 233 len = (unsigned int)get_byte(s); 234 len += ((unsigned int)get_byte(s)) << 8; 235 /* len is garbage if EOF but the loop below will quit anyway */ 236 while (len-- != 0 && get_byte(s) != EOF) 237 /*void*/; 238 } 239 if ((flags & ORIG_NAME) != 0) { 240 /* skip the original file name */ 241 while ((c = get_byte(s)) != 0 && c != EOF) 242 /*void*/; 243 } 244 if ((flags & COMMENT) != 0) { 245 /* skip the .gz file comment */ 246 while ((c = get_byte(s)) != 0 && c != EOF) 247 /*void*/; 248 } 249 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ 250 for (len = 0; len < 2; len++) 251 (void)get_byte(s); 252 } 253 s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK; 254 } 255 256 /* 257 * new open(), close(), read(), lseek() 258 */ 259 260 int 261 open(const char *fname, int mode) 262 { 263 int fd; 264 struct sd *s = 0; 265 266 if (((fd = oopen(fname, mode)) == -1) || (mode != 0)) 267 /* compression only for read */ 268 return fd; 269 270 ss[fd] = s = alloc(sizeof(struct sd)); 271 if (s == 0) 272 goto errout; 273 (void)memset(s, 0, sizeof(struct sd)); 274 275 if (inflateInit2(&(s->stream), -15) != Z_OK) 276 goto errout; 277 278 s->stream.next_in = s->inbuf = (unsigned char *)alloc(Z_BUFSIZE); 279 if (s->inbuf == 0) { 280 inflateEnd(&(s->stream)); 281 goto errout; 282 } 283 284 s->fd = fd; 285 check_header(s); /* skip the .gz header */ 286 return fd; 287 288 errout: 289 if (s != 0) 290 dealloc(s, sizeof(struct sd)); 291 ss[fd] = NULL; 292 oclose(fd); 293 return -1; 294 } 295 296 int 297 close(int fd) 298 { 299 struct sd *s; 300 301 #if !defined(LIBSA_NO_FD_CHECKING) 302 if ((unsigned int)fd >= SOPEN_MAX) { 303 errno = EBADF; 304 return -1; 305 } 306 #endif 307 308 s = ss[fd]; 309 310 if (s != NULL) { 311 inflateEnd(&(s->stream)); 312 313 dealloc(s->inbuf, Z_BUFSIZE); 314 dealloc(s, sizeof(struct sd)); 315 } 316 317 return oclose(fd); 318 } 319 320 ssize_t 321 read(int fd, void *buf, size_t len) 322 { 323 struct sd *s; 324 #if !defined(LIBSA_CREAD_NOCRC) 325 unsigned char *start = buf; /* starting point for crc computation */ 326 #endif 327 328 s = ss[fd]; 329 330 if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) 331 return -1; 332 if (s->z_err == Z_STREAM_END) 333 return 0; /* EOF */ 334 335 s->stream.next_out = buf; 336 s->stream.avail_out = len; 337 338 while (s->stream.avail_out != 0) { 339 340 if (s->compressed == 0) { 341 /* Copy first the lookahead bytes: */ 342 unsigned int n = s->stream.avail_in; 343 if (n > s->stream.avail_out) 344 n = s->stream.avail_out; 345 if (n > 0) { 346 zmemcpy(s->stream.next_out, 347 s->stream.next_in, n); 348 s->stream.next_out += n; 349 s->stream.next_in += n; 350 s->stream.avail_out -= n; 351 s->stream.avail_in -= n; 352 } 353 if (s->stream.avail_out > 0) { 354 int got; 355 got = oread(s->fd, s->stream.next_out, 356 s->stream.avail_out); 357 if (got == -1) 358 return got; 359 s->stream.avail_out -= got; 360 } 361 return (int)(len - s->stream.avail_out); 362 } 363 364 if (s->stream.avail_in == 0 && !s->z_eof) { 365 int got; 366 errno = 0; 367 got = oread(fd, s->inbuf, Z_BUFSIZE); 368 if (got <= 0) { 369 s->z_eof = 1; 370 if (errno) { 371 s->z_err = Z_ERRNO; 372 break; 373 } 374 } 375 s->stream.avail_in = got; 376 s->stream.next_in = s->inbuf; 377 } 378 379 s->z_err = inflate(&(s->stream), Z_NO_FLUSH); 380 381 if (s->z_err == Z_STREAM_END) { 382 uint32_t total_out; 383 #if !defined(LIBSA_CREAD_NOCRC) 384 uint32_t crc; 385 /* Check CRC and original size */ 386 s->crc = crc32(s->crc, start, (unsigned int) 387 (s->stream.next_out - start)); 388 start = s->stream.next_out; 389 crc = getLong(s); 390 #else 391 (void)getLong(s); 392 #endif 393 total_out = getLong(s); 394 395 if ( 396 #if !defined(LIBSA_CREAD_NOCRC) 397 crc != s->crc || 398 #endif 399 total_out != s->stream.total_out) { 400 401 s->z_err = Z_DATA_ERROR; 402 } else { 403 /* Check for concatenated .gz files: */ 404 check_header(s); 405 if (s->z_err == Z_OK) { 406 inflateReset(&(s->stream)); 407 #if !defined(LIBSA_CREAD_NOCRC) 408 s->crc = crc32(0L, Z_NULL, 0); 409 #endif 410 } 411 } 412 } 413 if (s->z_err != Z_OK || s->z_eof) 414 break; 415 } 416 417 #if !defined(LIBSA_CREAD_NOCRC) 418 s->crc = crc32(s->crc, start, 419 (unsigned int)(s->stream.next_out - start)); 420 #endif 421 422 return (int)(len - s->stream.avail_out); 423 } 424 425 off_t 426 lseek(int fd, off_t offset, int where) 427 { 428 struct open_file *f; 429 struct sd *s; 430 431 #if !defined(LIBSA_NO_FD_CHECKING) 432 if ((unsigned int)fd >= SOPEN_MAX) { 433 errno = EBADF; 434 return -1; 435 } 436 #endif 437 f = &files[fd]; 438 439 if ((f->f_flags & F_READ) == 0) 440 return olseek(fd, offset, where); 441 442 s = ss[fd]; 443 444 if(s->compressed == 0) { 445 off_t res = olseek(fd, offset, where); 446 if (res != (off_t)-1) { 447 /* make sure the lookahead buffer is invalid */ 448 s->stream.avail_in = 0; 449 } 450 return res; 451 } 452 453 switch(where) { 454 case SEEK_CUR: 455 offset += s->stream.total_out; 456 case SEEK_SET: 457 /* if seek backwards, simply start from the beginning */ 458 if (offset < s->stream.total_out) { 459 off_t res; 460 void *sav_inbuf; 461 462 res = olseek(fd, 0, SEEK_SET); 463 if(res == (off_t)-1) 464 return res; 465 /* ??? perhaps fallback to close / open */ 466 467 inflateEnd(&(s->stream)); 468 469 sav_inbuf = s->inbuf; /* don't allocate again */ 470 (void)memset(s, 0, sizeof(struct sd)); 471 /* this resets total_out to 0! */ 472 473 inflateInit2(&(s->stream), -15); 474 s->stream.next_in = s->inbuf = sav_inbuf; 475 476 s->fd = fd; 477 check_header(s); /* skip the .gz header */ 478 } 479 480 /* to seek forwards, throw away data */ 481 if (offset > s->stream.total_out) { 482 off_t toskip = offset - s->stream.total_out; 483 484 while (toskip > 0) { 485 #define DUMMYBUFSIZE 256 486 char dummybuf[DUMMYBUFSIZE]; 487 off_t len = toskip; 488 489 if (len > DUMMYBUFSIZE) 490 len = DUMMYBUFSIZE; 491 if (read(fd, dummybuf, len) != len) { 492 errno = EOFFSET; 493 return (off_t)-1; 494 } 495 toskip -= len; 496 } 497 } 498 #ifdef DEBUG 499 if (offset != s->stream.total_out) 500 panic("lseek compressed"); 501 #endif 502 return offset; 503 case SEEK_END: 504 errno = EOFFSET; 505 break; 506 default: 507 errno = EINVAL; 508 break; 509 } 510 511 return (off_t)-1; 512 } 513
Indexes created Thu Oct 23 22:10:10 GMT 2025