1 /* 2 * Copyright (c) Ian F. Darwin 1986-1995. 3 * Software written by Ian F. Darwin and others; 4 * maintained 1995-present by Christos Zoulas and others. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice immediately at the beginning of the file, without modification, 11 * 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 AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 /* 29 * compress routines: 30 * zmagic() - returns 0 if not recognized, uncompresses and prints 31 * information if recognized 32 * uncompress(method, old, n, newch) - uncompress old into new, 33 * using method, return sizeof new 34 */ 35 #include "file.h" 36 37 #ifndef lint 38 FILE_RCSID("@(#)$File: compress.c,v 1.65 2010/07/21 16:47:17 christos Exp $") 39 #endif 40 41 #include "magic.h" 42 #include <stdlib.h> 43 #ifdef HAVE_UNISTD_H 44 #include <unistd.h> 45 #endif 46 #include <string.h> 47 #include <errno.h> 48 #ifndef __MINGW32__ 49 #include <sys/ioctl.h> 50 #endif 51 #ifdef HAVE_SYS_WAIT_H 52 #include <sys/wait.h> 53 #endif 54 #if defined(HAVE_SYS_TIME_H) 55 #include <sys/time.h> 56 #endif 57 #if defined(HAVE_ZLIB_H) && defined(HAVE_LIBZ) 58 #define BUILTIN_DECOMPRESS 59 #include <zlib.h> 60 #endif 61 62 private const struct { 63 const char magic[8]; 64 size_t maglen; 65 const char *argv[3]; 66 int silent; 67 } compr[] = { 68 { "\037\235", 2, { "gzip", "-cdq", NULL }, 1 }, /* compressed */ 69 /* Uncompress can get stuck; so use gzip first if we have it 70 * Idea from Damien Clark, thanks! */ 71 { "\037\235", 2, { "uncompress", "-c", NULL }, 1 }, /* compressed */ 72 { "\037\213", 2, { "gzip", "-cdq", NULL }, 1 }, /* gzipped */ 73 { "\037\236", 2, { "gzip", "-cdq", NULL }, 1 }, /* frozen */ 74 { "\037\240", 2, { "gzip", "-cdq", NULL }, 1 }, /* SCO LZH */ 75 /* the standard pack utilities do not accept standard input */ 76 { "\037\036", 2, { "gzip", "-cdq", NULL }, 0 }, /* packed */ 77 { "PK\3\4", 4, { "gzip", "-cdq", NULL }, 1 }, /* pkzipped, */ 78 /* ...only first file examined */ 79 { "BZh", 3, { "bzip2", "-cd", NULL }, 1 }, /* bzip2-ed */ 80 { "LZIP", 4, { "lzip", "-cdq", NULL }, 1 }, 81 { "\3757zXZ\0",6,{ "xz", "-cd", NULL }, 1 }, /* XZ Utils */ 82 }; 83 84 #define NODATA ((size_t)~0) 85 86 private ssize_t swrite(int, const void *, size_t); 87 #if HAVE_FORK 88 private size_t ncompr = sizeof(compr) / sizeof(compr[0]); 89 private size_t uncompressbuf(struct magic_set *, int, size_t, 90 const unsigned char *, unsigned char **, size_t); 91 #ifdef BUILTIN_DECOMPRESS 92 private size_t uncompressgzipped(struct magic_set *, const unsigned char *, 93 unsigned char **, size_t); 94 #endif 95 96 protected int 97 file_zmagic(struct magic_set *ms, int fd, const char *name, 98 const unsigned char *buf, size_t nbytes) 99 { 100 unsigned char *newbuf = NULL; 101 size_t i, nsz; 102 int rv = 0; 103 int mime = ms->flags & MAGIC_MIME; 104 105 if ((ms->flags & MAGIC_COMPRESS) == 0) 106 return 0; 107 108 for (i = 0; i < ncompr; i++) { 109 if (nbytes < compr[i].maglen) 110 continue; 111 if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 && 112 (nsz = uncompressbuf(ms, fd, i, buf, &newbuf, 113 nbytes)) != NODATA) { 114 ms->flags &= ~MAGIC_COMPRESS; 115 rv = -1; 116 if (file_buffer(ms, -1, name, newbuf, nsz) == -1) 117 goto error; 118 119 if (mime == MAGIC_MIME || mime == 0) { 120 if (file_printf(ms, mime ? 121 " compressed-encoding=" : " (") == -1) 122 goto error; 123 } 124 125 if ((mime == 0 || mime & MAGIC_MIME_ENCODING) && 126 file_buffer(ms, -1, NULL, buf, nbytes) == -1) 127 goto error; 128 129 if (!mime && file_printf(ms, ")") == -1) 130 goto error; 131 rv = 1; 132 break; 133 } 134 } 135 error: 136 if (newbuf) 137 free(newbuf); 138 ms->flags |= MAGIC_COMPRESS; 139 return rv; 140 } 141 #endif 142 /* 143 * `safe' write for sockets and pipes. 144 */ 145 private ssize_t 146 swrite(int fd, const void *buf, size_t n) 147 { 148 ssize_t rv; 149 size_t rn = n; 150 151 do 152 switch (rv = write(fd, buf, n)) { 153 case -1: 154 if (errno == EINTR) 155 continue; 156 return -1; 157 default: 158 n -= rv; 159 buf = CAST(const char *, buf) + rv; 160 break; 161 } 162 while (n > 0); 163 return rn; 164 } 165 166 167 /* 168 * `safe' read for sockets and pipes. 169 */ 170 protected ssize_t 171 sread(int fd, void *buf, size_t n, int canbepipe __attribute__ ((unused))) 172 { 173 ssize_t rv; 174 #ifdef FD_ZERO 175 ssize_t cnt; 176 #endif 177 #ifdef FIONREAD 178 int t = 0; 179 #endif 180 size_t rn = n; 181 182 if (fd == STDIN_FILENO) 183 goto nocheck; 184 185 #ifdef FIONREAD 186 if ((canbepipe && (ioctl(fd, FIONREAD, &t) == -1)) || (t == 0)) { 187 #ifdef FD_ZERO 188 for (cnt = 0;; cnt++) { 189 fd_set check; 190 struct timeval tout = {0, 100 * 1000}; 191 int selrv; 192 193 FD_ZERO(&check); 194 FD_SET(fd, &check); 195 196 /* 197 * Avoid soft deadlock: do not read if there 198 * is nothing to read from sockets and pipes. 199 */ 200 selrv = select(fd + 1, &check, NULL, NULL, &tout); 201 if (selrv == -1) { 202 if (errno == EINTR || errno == EAGAIN) 203 continue; 204 } else if (selrv == 0 && cnt >= 5) { 205 return 0; 206 } else 207 break; 208 } 209 #endif 210 (void)ioctl(fd, FIONREAD, &t); 211 } 212 213 if (t > 0 && (size_t)t < n) { 214 n = t; 215 rn = n; 216 } 217 #endif 218 219 nocheck: 220 do 221 switch ((rv = read(fd, buf, n))) { 222 case -1: 223 if (errno == EINTR) 224 continue; 225 return -1; 226 case 0: 227 return rn - n; 228 default: 229 n -= rv; 230 buf = ((char *)buf) + rv; 231 break; 232 } 233 while (n > 0); 234 return rn; 235 } 236 237 protected int 238 file_pipe2file(struct magic_set *ms, int fd, const void *startbuf, 239 size_t nbytes) 240 { 241 char buf[4096]; 242 ssize_t r; 243 int tfd; 244 #ifdef HAVE_MKSTEMP 245 int te; 246 #endif 247 248 (void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf); 249 #ifndef HAVE_MKSTEMP 250 { 251 char *ptr = mktemp(buf); 252 tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600); 253 r = errno; 254 (void)unlink(ptr); 255 errno = r; 256 } 257 #else 258 tfd = mkstemp(buf); 259 te = errno; 260 (void)unlink(buf); 261 errno = te; 262 #endif 263 if (tfd == -1) { 264 file_error(ms, errno, 265 "cannot create temporary file for pipe copy"); 266 return -1; 267 } 268 269 if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes) 270 r = 1; 271 else { 272 while ((r = sread(fd, buf, sizeof(buf), 1)) > 0) 273 if (swrite(tfd, buf, (size_t)r) != r) 274 break; 275 } 276 277 switch (r) { 278 case -1: 279 file_error(ms, errno, "error copying from pipe to temp file"); 280 return -1; 281 case 0: 282 break; 283 default: 284 file_error(ms, errno, "error while writing to temp file"); 285 return -1; 286 } 287 288 /* 289 * We duplicate the file descriptor, because fclose on a 290 * tmpfile will delete the file, but any open descriptors 291 * can still access the phantom inode. 292 */ 293 if ((fd = dup2(tfd, fd)) == -1) { 294 file_error(ms, errno, "could not dup descriptor for temp file"); 295 return -1; 296 } 297 (void)close(tfd); 298 if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) { 299 file_badseek(ms); 300 return -1; 301 } 302 return fd; 303 } 304 #if HAVE_FORK 305 #ifdef BUILTIN_DECOMPRESS 306 307 #define FHCRC (1 << 1) 308 #define FEXTRA (1 << 2) 309 #define FNAME (1 << 3) 310 #define FCOMMENT (1 << 4) 311 312 private size_t 313 uncompressgzipped(struct magic_set *ms, const unsigned char *old, 314 unsigned char **newch, size_t n) 315 { 316 unsigned char flg = old[3]; 317 size_t data_start = 10; 318 z_stream z; 319 int rc; 320 321 if (flg & FEXTRA) { 322 if (data_start+1 >= n) 323 return 0; 324 data_start += 2 + old[data_start] + old[data_start + 1] * 256; 325 } 326 if (flg & FNAME) { 327 while(data_start < n && old[data_start]) 328 data_start++; 329 data_start++; 330 } 331 if(flg & FCOMMENT) { 332 while(data_start < n && old[data_start]) 333 data_start++; 334 data_start++; 335 } 336 if(flg & FHCRC) 337 data_start += 2; 338 339 if (data_start >= n) 340 return 0; 341 if ((*newch = CAST(unsigned char *, malloc(HOWMANY + 1))) == NULL) { 342 return 0; 343 } 344 345 /* XXX: const castaway, via strchr */ 346 z.next_in = (Bytef *)strchr((const char *)old + data_start, 347 old[data_start]); 348 z.avail_in = CAST(uint32_t, (n - data_start)); 349 z.next_out = *newch; 350 z.avail_out = HOWMANY; 351 z.zalloc = Z_NULL; 352 z.zfree = Z_NULL; 353 z.opaque = Z_NULL; 354 355 /* LINTED bug in header macro */ 356 rc = inflateInit2(&z, -15); 357 if (rc != Z_OK) { 358 file_error(ms, 0, "zlib: %s", z.msg); 359 return 0; 360 } 361 362 rc = inflate(&z, Z_SYNC_FLUSH); 363 if (rc != Z_OK && rc != Z_STREAM_END) { 364 file_error(ms, 0, "zlib: %s", z.msg); 365 return 0; 366 } 367 368 n = (size_t)z.total_out; 369 (void)inflateEnd(&z); 370 371 /* let's keep the nul-terminate tradition */ 372 (*newch)[n] = '\0'; 373 374 return n; 375 } 376 #endif 377 378 private size_t 379 uncompressbuf(struct magic_set *ms, int fd, size_t method, 380 const unsigned char *old, unsigned char **newch, size_t n) 381 { 382 int fdin[2], fdout[2]; 383 ssize_t r; 384 385 #ifdef BUILTIN_DECOMPRESS 386 /* FIXME: This doesn't cope with bzip2 */ 387 if (method == 2) 388 return uncompressgzipped(ms, old, newch, n); 389 #endif 390 (void)fflush(stdout); 391 (void)fflush(stderr); 392 393 if ((fd != -1 && pipe(fdin) == -1) || pipe(fdout) == -1) { 394 file_error(ms, errno, "cannot create pipe"); 395 return NODATA; 396 } 397 switch (fork()) { 398 case 0: /* child */ 399 (void) close(0); 400 if (fd != -1) { 401 (void) dup(fd); 402 (void) lseek(0, (off_t)0, SEEK_SET); 403 } else { 404 (void) dup(fdin[0]); 405 (void) close(fdin[0]); 406 (void) close(fdin[1]); 407 } 408 409 (void) close(1); 410 (void) dup(fdout[1]); 411 (void) close(fdout[0]); 412 (void) close(fdout[1]); 413 #ifndef DEBUG 414 if (compr[method].silent) 415 (void)close(2); 416 #endif 417 418 (void)execvp(compr[method].argv[0], 419 (char *const *)(intptr_t)compr[method].argv); 420 #ifdef DEBUG 421 (void)fprintf(stderr, "exec `%s' failed (%s)\n", 422 compr[method].argv[0], strerror(errno)); 423 #endif 424 exit(1); 425 /*NOTREACHED*/ 426 case -1: 427 file_error(ms, errno, "could not fork"); 428 return NODATA; 429 430 default: /* parent */ 431 (void) close(fdout[1]); 432 if (fd == -1) { 433 (void) close(fdin[0]); 434 /* 435 * fork again, to avoid blocking because both 436 * pipes filled 437 */ 438 switch (fork()) { 439 case 0: /* child */ 440 (void)close(fdout[0]); 441 if (swrite(fdin[1], old, n) != (ssize_t)n) { 442 #ifdef DEBUG 443 (void)fprintf(stderr, 444 "Write failed (%s)\n", 445 strerror(errno)); 446 #endif 447 exit(1); 448 } 449 exit(0); 450 /*NOTREACHED*/ 451 452 case -1: 453 #ifdef DEBUG 454 (void)fprintf(stderr, "Fork failed (%s)\n", 455 strerror(errno)); 456 #endif 457 exit(1); 458 /*NOTREACHED*/ 459 460 default: /* parent */ 461 break; 462 } 463 (void) close(fdin[1]); 464 fdin[1] = -1; 465 } 466 467 if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) { 468 #ifdef DEBUG 469 (void)fprintf(stderr, "Malloc failed (%s)\n", 470 strerror(errno)); 471 #endif 472 n = 0; 473 goto err; 474 } 475 if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) { 476 #ifdef DEBUG 477 (void)fprintf(stderr, "Read failed (%s)\n", 478 strerror(errno)); 479 #endif 480 free(*newch); 481 n = 0; 482 newch[0] = '\0'; 483 goto err; 484 } else { 485 n = r; 486 } 487 /* NUL terminate, as every buffer is handled here. */ 488 (*newch)[n] = '\0'; 489 err: 490 if (fdin[1] != -1) 491 (void) close(fdin[1]); 492 (void) close(fdout[0]); 493 #ifdef WNOHANG 494 while (waitpid(-1, NULL, WNOHANG) != -1) 495 continue; 496 #else 497 (void)wait(NULL); 498 #endif 499 (void) close(fdin[0]); 500 501 return n; 502 } 503 } 504 #endif 505