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 1.67 2011/09/01 12:12:37 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 }; 84 85 #define NODATA ((size_t)~0) 86 87 private ssize_t swrite(int, const void *, size_t); 88 #if HAVE_FORK 89 private size_t ncompr = sizeof(compr) / sizeof(compr[0]); 90 private size_t uncompressbuf(struct magic_set *, int, size_t, 91 const unsigned char *, unsigned char **, size_t); 92 #ifdef BUILTIN_DECOMPRESS 93 private size_t uncompressgzipped(struct magic_set *, const unsigned char *, 94 unsigned char **, size_t); 95 #endif 96 97 protected int 98 file_zmagic(struct magic_set *ms, int fd, const char *name, 99 const unsigned char *buf, size_t nbytes) 100 { 101 unsigned char *newbuf = NULL; 102 size_t i, nsz; 103 int rv = 0; 104 int mime = ms->flags & MAGIC_MIME; 105 106 if ((ms->flags & MAGIC_COMPRESS) == 0) 107 return 0; 108 109 for (i = 0; i < ncompr; i++) { 110 if (nbytes < compr[i].maglen) 111 continue; 112 if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 && 113 (nsz = uncompressbuf(ms, fd, i, buf, &newbuf, 114 nbytes)) != NODATA) { 115 ms->flags &= ~MAGIC_COMPRESS; 116 rv = -1; 117 if (file_buffer(ms, -1, name, newbuf, nsz) == -1) 118 goto error; 119 120 if (mime == MAGIC_MIME || mime == 0) { 121 if (file_printf(ms, mime ? 122 " compressed-encoding=" : " (") == -1) 123 goto error; 124 } 125 126 if ((mime == 0 || mime & MAGIC_MIME_ENCODING) && 127 file_buffer(ms, -1, NULL, buf, nbytes) == -1) 128 goto error; 129 130 if (!mime && file_printf(ms, ")") == -1) 131 goto error; 132 rv = 1; 133 break; 134 } 135 } 136 error: 137 if (newbuf) 138 free(newbuf); 139 ms->flags |= MAGIC_COMPRESS; 140 return rv; 141 } 142 #endif 143 /* 144 * `safe' write for sockets and pipes. 145 */ 146 private ssize_t 147 swrite(int fd, const void *buf, size_t n) 148 { 149 ssize_t rv; 150 size_t rn = n; 151 152 do 153 switch (rv = write(fd, buf, n)) { 154 case -1: 155 if (errno == EINTR) 156 continue; 157 return -1; 158 default: 159 n -= rv; 160 buf = CAST(const char *, buf) + rv; 161 break; 162 } 163 while (n > 0); 164 return rn; 165 } 166 167 168 /* 169 * `safe' read for sockets and pipes. 170 */ 171 protected ssize_t 172 sread(int fd, void *buf, size_t n, int canbepipe __attribute__ ((unused))) 173 { 174 ssize_t rv; 175 #ifdef FD_ZERO 176 ssize_t cnt; 177 #endif 178 #ifdef FIONREAD 179 int t = 0; 180 #endif 181 size_t rn = n; 182 183 if (fd == STDIN_FILENO) 184 goto nocheck; 185 186 #ifdef FIONREAD 187 if ((canbepipe && (ioctl(fd, FIONREAD, &t) == -1)) || (t == 0)) { 188 #ifdef FD_ZERO 189 for (cnt = 0;; cnt++) { 190 fd_set check; 191 struct timeval tout = {0, 100 * 1000}; 192 int selrv; 193 194 FD_ZERO(&check); 195 FD_SET(fd, &check); 196 197 /* 198 * Avoid soft deadlock: do not read if there 199 * is nothing to read from sockets and pipes. 200 */ 201 selrv = select(fd + 1, &check, NULL, NULL, &tout); 202 if (selrv == -1) { 203 if (errno == EINTR || errno == EAGAIN) 204 continue; 205 } else if (selrv == 0 && cnt >= 5) { 206 return 0; 207 } else 208 break; 209 } 210 #endif 211 (void)ioctl(fd, FIONREAD, &t); 212 } 213 214 if (t > 0 && (size_t)t < n) { 215 n = t; 216 rn = n; 217 } 218 #endif 219 220 nocheck: 221 do 222 switch ((rv = read(fd, buf, n))) { 223 case -1: 224 if (errno == EINTR) 225 continue; 226 return -1; 227 case 0: 228 return rn - n; 229 default: 230 n -= rv; 231 buf = ((char *)buf) + rv; 232 break; 233 } 234 while (n > 0); 235 return rn; 236 } 237 238 protected int 239 file_pipe2file(struct magic_set *ms, int fd, const void *startbuf, 240 size_t nbytes) 241 { 242 char buf[4096]; 243 ssize_t r; 244 int tfd; 245 #ifdef HAVE_MKSTEMP 246 int te; 247 #endif 248 249 (void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf); 250 #ifndef HAVE_MKSTEMP 251 { 252 char *ptr = mktemp(buf); 253 tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600); 254 r = errno; 255 (void)unlink(ptr); 256 errno = r; 257 } 258 #else 259 tfd = mkstemp(buf); 260 te = errno; 261 (void)unlink(buf); 262 errno = te; 263 #endif 264 if (tfd == -1) { 265 file_error(ms, errno, 266 "cannot create temporary file for pipe copy"); 267 return -1; 268 } 269 270 if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes) 271 r = 1; 272 else { 273 while ((r = sread(fd, buf, sizeof(buf), 1)) > 0) 274 if (swrite(tfd, buf, (size_t)r) != r) 275 break; 276 } 277 278 switch (r) { 279 case -1: 280 file_error(ms, errno, "error copying from pipe to temp file"); 281 return -1; 282 case 0: 283 break; 284 default: 285 file_error(ms, errno, "error while writing to temp file"); 286 return -1; 287 } 288 289 /* 290 * We duplicate the file descriptor, because fclose on a 291 * tmpfile will delete the file, but any open descriptors 292 * can still access the phantom inode. 293 */ 294 if ((fd = dup2(tfd, fd)) == -1) { 295 file_error(ms, errno, "could not dup descriptor for temp file"); 296 return -1; 297 } 298 (void)close(tfd); 299 if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) { 300 file_badseek(ms); 301 return -1; 302 } 303 return fd; 304 } 305 #if HAVE_FORK 306 #ifdef BUILTIN_DECOMPRESS 307 308 #define FHCRC (1 << 1) 309 #define FEXTRA (1 << 2) 310 #define FNAME (1 << 3) 311 #define FCOMMENT (1 << 4) 312 313 private size_t 314 uncompressgzipped(struct magic_set *ms, const unsigned char *old, 315 unsigned char **newch, size_t n) 316 { 317 unsigned char flg = old[3]; 318 size_t data_start = 10; 319 z_stream z; 320 int rc; 321 322 if (flg & FEXTRA) { 323 if (data_start+1 >= n) 324 return 0; 325 data_start += 2 + old[data_start] + old[data_start + 1] * 256; 326 } 327 if (flg & FNAME) { 328 while(data_start < n && old[data_start]) 329 data_start++; 330 data_start++; 331 } 332 if(flg & FCOMMENT) { 333 while(data_start < n && old[data_start]) 334 data_start++; 335 data_start++; 336 } 337 if(flg & FHCRC) 338 data_start += 2; 339 340 if (data_start >= n) 341 return 0; 342 if ((*newch = CAST(unsigned char *, malloc(HOWMANY + 1))) == NULL) { 343 return 0; 344 } 345 346 /* XXX: const castaway, via strchr */ 347 z.next_in = (Bytef *)strchr((const char *)old + data_start, 348 old[data_start]); 349 z.avail_in = CAST(uint32_t, (n - data_start)); 350 z.next_out = *newch; 351 z.avail_out = HOWMANY; 352 z.zalloc = Z_NULL; 353 z.zfree = Z_NULL; 354 z.opaque = Z_NULL; 355 356 /* LINTED bug in header macro */ 357 rc = inflateInit2(&z, -15); 358 if (rc != Z_OK) { 359 file_error(ms, 0, "zlib: %s", z.msg); 360 return 0; 361 } 362 363 rc = inflate(&z, Z_SYNC_FLUSH); 364 if (rc != Z_OK && rc != Z_STREAM_END) { 365 file_error(ms, 0, "zlib: %s", z.msg); 366 return 0; 367 } 368 369 n = (size_t)z.total_out; 370 (void)inflateEnd(&z); 371 372 /* let's keep the nul-terminate tradition */ 373 (*newch)[n] = '\0'; 374 375 return n; 376 } 377 #endif 378 379 private size_t 380 uncompressbuf(struct magic_set *ms, int fd, size_t method, 381 const unsigned char *old, unsigned char **newch, size_t n) 382 { 383 int fdin[2], fdout[2]; 384 ssize_t r; 385 pid_t pid; 386 387 #ifdef BUILTIN_DECOMPRESS 388 /* FIXME: This doesn't cope with bzip2 */ 389 if (method == 2) 390 return uncompressgzipped(ms, old, newch, n); 391 #endif 392 (void)fflush(stdout); 393 (void)fflush(stderr); 394 395 if ((fd != -1 && pipe(fdin) == -1) || pipe(fdout) == -1) { 396 file_error(ms, errno, "cannot create pipe"); 397 return NODATA; 398 } 399 switch (pid = fork()) { 400 case 0: /* child */ 401 (void) close(0); 402 if (fd != -1) { 403 (void) dup(fd); 404 (void) lseek(0, (off_t)0, SEEK_SET); 405 } else { 406 (void) dup(fdin[0]); 407 (void) close(fdin[0]); 408 (void) close(fdin[1]); 409 } 410 411 (void) close(1); 412 (void) dup(fdout[1]); 413 (void) close(fdout[0]); 414 (void) close(fdout[1]); 415 #ifndef DEBUG 416 if (compr[method].silent) 417 (void)close(2); 418 #endif 419 420 (void)execvp(compr[method].argv[0], 421 (char *const *)(intptr_t)compr[method].argv); 422 #ifdef DEBUG 423 (void)fprintf(stderr, "exec `%s' failed (%s)\n", 424 compr[method].argv[0], strerror(errno)); 425 #endif 426 exit(1); 427 /*NOTREACHED*/ 428 case -1: 429 file_error(ms, errno, "could not fork"); 430 return NODATA; 431 432 default: /* parent */ 433 (void) close(fdout[1]); 434 if (fd == -1) { 435 (void) close(fdin[0]); 436 /* 437 * fork again, to avoid blocking because both 438 * pipes filled 439 */ 440 switch (fork()) { 441 case 0: /* child */ 442 (void)close(fdout[0]); 443 if (swrite(fdin[1], old, n) != (ssize_t)n) { 444 #ifdef DEBUG 445 (void)fprintf(stderr, 446 "Write failed (%s)\n", 447 strerror(errno)); 448 #endif 449 exit(1); 450 } 451 exit(0); 452 /*NOTREACHED*/ 453 454 case -1: 455 #ifdef DEBUG 456 (void)fprintf(stderr, "Fork failed (%s)\n", 457 strerror(errno)); 458 #endif 459 exit(1); 460 /*NOTREACHED*/ 461 462 default: /* parent */ 463 break; 464 } 465 (void) close(fdin[1]); 466 fdin[1] = -1; 467 } 468 469 if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) { 470 #ifdef DEBUG 471 (void)fprintf(stderr, "Malloc failed (%s)\n", 472 strerror(errno)); 473 #endif 474 n = 0; 475 goto err; 476 } 477 if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) { 478 #ifdef DEBUG 479 (void)fprintf(stderr, "Read failed (%s)\n", 480 strerror(errno)); 481 #endif 482 free(*newch); 483 n = 0; 484 newch[0] = '\0'; 485 goto err; 486 } else { 487 n = r; 488 } 489 /* NUL terminate, as every buffer is handled here. */ 490 (*newch)[n] = '\0'; 491 err: 492 if (fdin[1] != -1) 493 (void) close(fdin[1]); 494 (void) close(fdout[0]); 495 #ifdef WNOHANG 496 while (waitpid(pid, NULL, WNOHANG) != -1) 497 continue; 498 #else 499 (void)wait(NULL); 500 #endif 501 (void) close(fdin[0]); 502 503 return n; 504 } 505 } 506 #endif 507