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 1.73 2014/01/05 15:55:21 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 { "LRZI", 4, { "lrzip", "-dqo-", NULL }, 1 }, /* LRZIP */ 83 { "\004\"M\030", 4, { "lz4", "-cd", NULL }, 1 }, /* LZ4 */ 84 }; 85 86 #define NODATA ((size_t)~0) 87 88 private ssize_t swrite(int, const void *, size_t); 89 #if HAVE_FORK 90 private size_t ncompr = sizeof(compr) / sizeof(compr[0]); 91 private size_t uncompressbuf(struct magic_set *, int, size_t, 92 const unsigned char *, unsigned char **, size_t); 93 #ifdef BUILTIN_DECOMPRESS 94 private size_t uncompressgzipped(struct magic_set *, const unsigned char *, 95 unsigned char **, size_t); 96 #endif 97 98 protected int 99 file_zmagic(struct magic_set *ms, int fd, const char *name, 100 const unsigned char *buf, size_t nbytes) 101 { 102 unsigned char *newbuf = NULL; 103 size_t i, nsz; 104 int rv = 0; 105 int mime = ms->flags & MAGIC_MIME; 106 107 if ((ms->flags & MAGIC_COMPRESS) == 0) 108 return 0; 109 110 for (i = 0; i < ncompr; i++) { 111 if (nbytes < compr[i].maglen) 112 continue; 113 if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 && 114 (nsz = uncompressbuf(ms, fd, i, buf, &newbuf, 115 nbytes)) != NODATA) { 116 ms->flags &= ~MAGIC_COMPRESS; 117 rv = -1; 118 if (file_buffer(ms, -1, name, newbuf, nsz) == -1) 119 goto error; 120 121 if (mime == MAGIC_MIME || mime == 0) { 122 if (file_printf(ms, mime ? 123 " compressed-encoding=" : " (") == -1) 124 goto error; 125 if (file_buffer(ms, -1, NULL, buf, nbytes) == -1) 126 goto error; 127 if (!mime && file_printf(ms, ")") == -1) 128 goto error; 129 } 130 131 rv = 1; 132 break; 133 } 134 } 135 error: 136 free(newbuf); 137 ms->flags |= MAGIC_COMPRESS; 138 return rv; 139 } 140 #endif 141 /* 142 * `safe' write for sockets and pipes. 143 */ 144 private ssize_t 145 swrite(int fd, const void *buf, size_t n) 146 { 147 ssize_t rv; 148 size_t rn = n; 149 150 do 151 switch (rv = write(fd, buf, n)) { 152 case -1: 153 if (errno == EINTR) 154 continue; 155 return -1; 156 default: 157 n -= rv; 158 buf = CAST(const char *, buf) + rv; 159 break; 160 } 161 while (n > 0); 162 return rn; 163 } 164 165 166 /* 167 * `safe' read for sockets and pipes. 168 */ 169 protected ssize_t 170 sread(int fd, void *buf, size_t n, int canbepipe __attribute__((__unused__))) 171 { 172 ssize_t rv; 173 #ifdef FIONREAD 174 int t = 0; 175 #endif 176 size_t rn = n; 177 178 if (fd == STDIN_FILENO) 179 goto nocheck; 180 181 #ifdef FIONREAD 182 if (canbepipe && (ioctl(fd, FIONREAD, &t) == -1 || t == 0)) { 183 #ifdef FD_ZERO 184 ssize_t cnt; 185 for (cnt = 0;; cnt++) { 186 fd_set check; 187 struct timeval tout = {0, 100 * 1000}; 188 int selrv; 189 190 FD_ZERO(&check); 191 FD_SET(fd, &check); 192 193 /* 194 * Avoid soft deadlock: do not read if there 195 * is nothing to read from sockets and pipes. 196 */ 197 selrv = select(fd + 1, &check, NULL, NULL, &tout); 198 if (selrv == -1) { 199 if (errno == EINTR || errno == EAGAIN) 200 continue; 201 } else if (selrv == 0 && cnt >= 5) { 202 return 0; 203 } else 204 break; 205 } 206 #endif 207 (void)ioctl(fd, FIONREAD, &t); 208 } 209 210 if (t > 0 && (size_t)t < n) { 211 n = t; 212 rn = n; 213 } 214 #endif 215 216 nocheck: 217 do 218 switch ((rv = read(fd, buf, n))) { 219 case -1: 220 if (errno == EINTR) 221 continue; 222 return -1; 223 case 0: 224 return rn - n; 225 default: 226 n -= rv; 227 buf = ((char *)buf) + rv; 228 break; 229 } 230 while (n > 0); 231 return rn; 232 } 233 234 protected int 235 file_pipe2file(struct magic_set *ms, int fd, const void *startbuf, 236 size_t nbytes) 237 { 238 char buf[4096]; 239 ssize_t r; 240 int tfd; 241 242 (void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf); 243 #ifndef HAVE_MKSTEMP 244 { 245 char *ptr = mktemp(buf); 246 tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600); 247 r = errno; 248 (void)unlink(ptr); 249 errno = r; 250 } 251 #else 252 { 253 int te; 254 tfd = mkstemp(buf); 255 te = errno; 256 (void)unlink(buf); 257 errno = te; 258 } 259 #endif 260 if (tfd == -1) { 261 file_error(ms, errno, 262 "cannot create temporary file for pipe copy"); 263 return -1; 264 } 265 266 if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes) 267 r = 1; 268 else { 269 while ((r = sread(fd, buf, sizeof(buf), 1)) > 0) 270 if (swrite(tfd, buf, (size_t)r) != r) 271 break; 272 } 273 274 switch (r) { 275 case -1: 276 file_error(ms, errno, "error copying from pipe to temp file"); 277 return -1; 278 case 0: 279 break; 280 default: 281 file_error(ms, errno, "error while writing to temp file"); 282 return -1; 283 } 284 285 /* 286 * We duplicate the file descriptor, because fclose on a 287 * tmpfile will delete the file, but any open descriptors 288 * can still access the phantom inode. 289 */ 290 if ((fd = dup2(tfd, fd)) == -1) { 291 file_error(ms, errno, "could not dup descriptor for temp file"); 292 return -1; 293 } 294 (void)close(tfd); 295 if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) { 296 file_badseek(ms); 297 return -1; 298 } 299 return fd; 300 } 301 #if HAVE_FORK 302 #ifdef BUILTIN_DECOMPRESS 303 304 #define FHCRC (1 << 1) 305 #define FEXTRA (1 << 2) 306 #define FNAME (1 << 3) 307 #define FCOMMENT (1 << 4) 308 309 private size_t 310 uncompressgzipped(struct magic_set *ms, const unsigned char *old, 311 unsigned char **newch, size_t n) 312 { 313 unsigned char flg = old[3]; 314 size_t data_start = 10; 315 z_stream z; 316 int rc; 317 318 if (flg & FEXTRA) { 319 if (data_start+1 >= n) 320 return 0; 321 data_start += 2 + old[data_start] + old[data_start + 1] * 256; 322 } 323 if (flg & FNAME) { 324 while(data_start < n && old[data_start]) 325 data_start++; 326 data_start++; 327 } 328 if(flg & FCOMMENT) { 329 while(data_start < n && old[data_start]) 330 data_start++; 331 data_start++; 332 } 333 if(flg & FHCRC) 334 data_start += 2; 335 336 if (data_start >= n) 337 return 0; 338 if ((*newch = CAST(unsigned char *, malloc(HOWMANY + 1))) == NULL) { 339 return 0; 340 } 341 342 /* XXX: const castaway, via strchr */ 343 z.next_in = (Bytef *)strchr((const char *)old + data_start, 344 old[data_start]); 345 z.avail_in = CAST(uint32_t, (n - data_start)); 346 z.next_out = *newch; 347 z.avail_out = HOWMANY; 348 z.zalloc = Z_NULL; 349 z.zfree = Z_NULL; 350 z.opaque = Z_NULL; 351 352 /* LINTED bug in header macro */ 353 rc = inflateInit2(&z, -15); 354 if (rc != Z_OK) { 355 file_error(ms, 0, "zlib: %s", z.msg); 356 return 0; 357 } 358 359 rc = inflate(&z, Z_SYNC_FLUSH); 360 if (rc != Z_OK && rc != Z_STREAM_END) { 361 file_error(ms, 0, "zlib: %s", z.msg); 362 return 0; 363 } 364 365 n = (size_t)z.total_out; 366 (void)inflateEnd(&z); 367 368 /* let's keep the nul-terminate tradition */ 369 (*newch)[n] = '\0'; 370 371 return n; 372 } 373 #endif 374 375 private size_t 376 uncompressbuf(struct magic_set *ms, int fd, size_t method, 377 const unsigned char *old, unsigned char **newch, size_t n) 378 { 379 int fdin[2], fdout[2]; 380 ssize_t r; 381 pid_t pid; 382 383 #ifdef BUILTIN_DECOMPRESS 384 /* FIXME: This doesn't cope with bzip2 */ 385 if (method == 2) 386 return uncompressgzipped(ms, old, newch, n); 387 #endif 388 (void)fflush(stdout); 389 (void)fflush(stderr); 390 391 if ((fd != -1 && pipe(fdin) == -1) || pipe(fdout) == -1) { 392 file_error(ms, errno, "cannot create pipe"); 393 return NODATA; 394 } 395 switch (pid = fork()) { 396 case 0: /* child */ 397 (void) close(0); 398 if (fd != -1) { 399 if (dup(fd) == -1) 400 _exit(1); 401 (void) lseek(0, (off_t)0, SEEK_SET); 402 } else { 403 if (dup(fdin[0]) == -1) 404 _exit(1); 405 (void) close(fdin[0]); 406 (void) close(fdin[1]); 407 } 408 409 (void) close(1); 410 if (dup(fdout[1]) == -1) 411 _exit(1); 412 (void) close(fdout[0]); 413 (void) close(fdout[1]); 414 #ifndef DEBUG 415 if (compr[method].silent) 416 (void)close(2); 417 #endif 418 419 (void)execvp(compr[method].argv[0], 420 (char *const *)(intptr_t)compr[method].argv); 421 #ifdef DEBUG 422 (void)fprintf(stderr, "exec `%s' failed (%s)\n", 423 compr[method].argv[0], strerror(errno)); 424 #endif 425 exit(1); 426 /*NOTREACHED*/ 427 case -1: 428 file_error(ms, errno, "could not fork"); 429 return NODATA; 430 431 default: /* parent */ 432 (void) close(fdout[1]); 433 if (fd == -1) { 434 (void) close(fdin[0]); 435 /* 436 * fork again, to avoid blocking because both 437 * pipes filled 438 */ 439 switch (fork()) { 440 case 0: /* child */ 441 (void)close(fdout[0]); 442 if (swrite(fdin[1], old, n) != (ssize_t)n) { 443 #ifdef DEBUG 444 (void)fprintf(stderr, 445 "Write failed (%s)\n", 446 strerror(errno)); 447 #endif 448 exit(1); 449 } 450 exit(0); 451 /*NOTREACHED*/ 452 453 case -1: 454 #ifdef DEBUG 455 (void)fprintf(stderr, "Fork failed (%s)\n", 456 strerror(errno)); 457 #endif 458 exit(1); 459 /*NOTREACHED*/ 460 461 default: /* parent */ 462 break; 463 } 464 (void) close(fdin[1]); 465 fdin[1] = -1; 466 } 467 468 if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) { 469 #ifdef DEBUG 470 (void)fprintf(stderr, "Malloc failed (%s)\n", 471 strerror(errno)); 472 #endif 473 n = 0; 474 goto err; 475 } 476 if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) { 477 #ifdef DEBUG 478 (void)fprintf(stderr, "Read failed (%s)\n", 479 strerror(errno)); 480 #endif 481 free(*newch); 482 n = 0; 483 *newch = NULL; 484 goto err; 485 } else { 486 n = r; 487 } 488 /* NUL terminate, as every buffer is handled here. */ 489 (*newch)[n] = '\0'; 490 err: 491 if (fdin[1] != -1) 492 (void) close(fdin[1]); 493 (void) close(fdout[0]); 494 #ifdef WNOHANG 495 while (waitpid(pid, NULL, WNOHANG) != -1) 496 continue; 497 #else 498 (void)wait(NULL); 499 #endif 500 (void) close(fdin[0]); 501 502 return n; 503 } 504 } 505 #endif 506