external/bsd/file/dist/src/compress.c

   1 /*      $NetBSD: compress.c,v 1.1.1.1 2009/05/08 16:35:06 christos Exp $        */
   2
   3 /*
   4  * Copyright (c) Ian F. Darwin 1986-1995.
   5  * Software written by Ian F. Darwin and others;
   6  * maintained 1995-present by Christos Zoulas and others.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice immediately at the beginning of the file, without modification,
  13  *    this list of conditions, and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  22  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30 /*
  31  * compress routines:
  32  *      zmagic() - returns 0 if not recognized, uncompresses and prints
  33  *                 information if recognized
  34  *      uncompress(method, old, n, newch) - uncompress old into new,
  35  *                                          using method, return sizeof new
  36  */
  37 #include "file.h"
  38
  39 #ifndef lint
  40 #if 0
  41 FILE_RCSID("@(#)$File: compress.c,v 1.63 2009/03/23 14:21:51 christos Exp $")
  42 #else
  43 __RCSID("$NetBSD: compress.c,v 1.1.1.1 2009/05/08 16:35:06 christos Exp $");
  44 #endif
  45 #endif
  46
  47 #include "magic.h"
  48 #include <stdlib.h>
  49 #ifdef HAVE_UNISTD_H
  50 #include <unistd.h>
  51 #endif
  52 #include <string.h>
  53 #include <errno.h>
  54 #include <sys/ioctl.h>
  55 #ifdef HAVE_SYS_WAIT_H
  56 #include <sys/wait.h>
  57 #endif
  58 #if defined(HAVE_SYS_TIME_H)
  59 #include <sys/time.h>
  60 #endif
  61 #if defined(HAVE_ZLIB_H) && defined(HAVE_LIBZ)
  62 #define BUILTIN_DECOMPRESS
  63 #include <zlib.h>
  64 #endif
  65
  66 private const struct {
  67         const char magic[8];
  68         size_t maglen;
  69         const char *argv[3];
  70         int silent;
  71 } compr[] = {
  72         { "\037\235", 2, { "gzip", "-cdq", NULL }, 1 },         /* compressed */
  73         /* Uncompress can get stuck; so use gzip first if we have it
  74          * Idea from Damien Clark, thanks! */
  75         { "\037\235", 2, { "uncompress", "-c", NULL }, 1 },     /* compressed */
  76         { "\037\213", 2, { "gzip", "-cdq", NULL }, 1 },         /* gzipped */
  77         { "\037\236", 2, { "gzip", "-cdq", NULL }, 1 },         /* frozen */
  78         { "\037\240", 2, { "gzip", "-cdq", NULL }, 1 },         /* SCO LZH */
  79         /* the standard pack utilities do not accept standard input */
  80         { "\037\036", 2, { "gzip", "-cdq", NULL }, 0 },         /* packed */
  81         { "PK\3\4",   4, { "gzip", "-cdq", NULL }, 1 },         /* pkzipped, */
  82                                             /* ...only first file examined */
  83         { "BZh",      3, { "bzip2", "-cd", NULL }, 1 },         /* bzip2-ed */
  84         { "LZIP",     4, { "lzip", "-cdq", NULL }, 1 },
  85         { "\3757zXZ\0",6,{ "xz", "-cd", NULL }, 1 },            /* XZ Utils */
  86 };
  87
  88 private size_t ncompr = sizeof(compr) / sizeof(compr[0]);
  89
  90 #define NODATA ((size_t)~0)
  91
  92
  93 private ssize_t swrite(int, const void *, size_t);
  94 private size_t uncompressbuf(struct magic_set *, int, size_t,
  95     const unsigned char *, unsigned char **, size_t);
  96 #ifdef BUILTIN_DECOMPRESS
  97 private size_t uncompressgzipped(struct magic_set *, const unsigned char *,
  98     unsigned char **, size_t);
  99 #endif
 100
 101 protected int
 102 file_zmagic(struct magic_set *ms, int fd, const char *name,
 103     const unsigned char *buf, size_t nbytes)
 104 {
 105         unsigned char *newbuf = NULL;
 106         size_t i, nsz;
 107         int rv = 0;
 108         int mime = ms->flags & MAGIC_MIME;
 109
 110         if ((ms->flags & MAGIC_COMPRESS) == 0)
 111                 return 0;
 112
 113         for (i = 0; i < ncompr; i++) {
 114                 if (nbytes < compr[i].maglen)
 115                         continue;
 116                 if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 &&
 117                     (nsz = uncompressbuf(ms, fd, i, buf, &newbuf,
 118                     nbytes)) != NODATA) {
 119                         ms->flags &= ~MAGIC_COMPRESS;
 120                         rv = -1;
 121                         if (file_buffer(ms, -1, name, newbuf, nsz) == -1)
 122                                 goto error;
 123
 124                         if (mime == MAGIC_MIME || mime == 0) {
 125                                 if (file_printf(ms, mime ?
 126                                     " compressed-encoding=" : " (") == -1)
 127                                         goto error;
 128                         }
 129
 130                         if ((mime == 0 || mime & MAGIC_MIME_ENCODING) &&
 131                             file_buffer(ms, -1, NULL, buf, nbytes) == -1)
 132                                 goto error;
 133
 134                         if (!mime && file_printf(ms, ")") == -1)
 135                                 goto error;
 136                         rv = 1;
 137                         break;
 138                 }
 139         }
 140 error:
 141         if (newbuf)
 142                 free(newbuf);
 143         ms->flags |= MAGIC_COMPRESS;
 144         return rv;
 145 }
 146
 147 /*
 148  * `safe' write for sockets and pipes.
 149  */
 150 private ssize_t
 151 swrite(int fd, const void *buf, size_t n)
 152 {
 153         ssize_t rv;
 154         size_t rn = n;
 155
 156         do
 157                 switch (rv = write(fd, buf, n)) {
 158                 case -1:
 159                         if (errno == EINTR)
 160                                 continue;
 161                         return -1;
 162                 default:
 163                         n -= rv;
 164                         buf = CAST(const char *, buf) + rv;
 165                         break;
 166                 }
 167         while (n > 0);
 168         return rn;
 169 }
 170
 171
 172 /*
 173  * `safe' read for sockets and pipes.
 174  */
 175 protected ssize_t
 176 sread(int fd, void *buf, size_t n, int canbepipe)
 177 {
 178         ssize_t rv, cnt;
 179 #ifdef FIONREAD
 180         int t = 0;
 181 #endif
 182         size_t rn = n;
 183
 184         if (fd == STDIN_FILENO)
 185                 goto nocheck;
 186
 187 #ifdef FIONREAD
 188         if ((canbepipe && (ioctl(fd, FIONREAD, &t) == -1)) || (t == 0)) {
 189 #ifdef FD_ZERO
 190                 for (cnt = 0;; cnt++) {
 191                         fd_set check;
 192                         struct timeval tout = {0, 100 * 1000};
 193                         int selrv;
 194
 195                         FD_ZERO(&check);
 196                         FD_SET(fd, &check);
 197
 198                         /*
 199                          * Avoid soft deadlock: do not read if there
 200                          * is nothing to read from sockets and pipes.
 201                          */
 202                         selrv = select(fd + 1, &check, NULL, NULL, &tout);
 203                         if (selrv == -1) {
 204                                 if (errno == EINTR || errno == EAGAIN)
 205                                         continue;
 206                         } else if (selrv == 0 && cnt >= 5) {
 207                                 return 0;
 208                         } else
 209                                 break;
 210                 }
 211 #endif
 212                 (void)ioctl(fd, FIONREAD, &t);
 213         }
 214
 215         if (t > 0 && (size_t)t < n) {
 216                 n = t;
 217                 rn = n;
 218         }
 219 #endif
 220
 221 nocheck:
 222         do
 223                 switch ((rv = read(fd, buf, n))) {
 224                 case -1:
 225                         if (errno == EINTR)
 226                                 continue;
 227                         return -1;
 228                 case 0:
 229                         return rn - n;
 230                 default:
 231                         n -= rv;
 232                         buf = ((char *)buf) + rv;
 233                         break;
 234                 }
 235         while (n > 0);
 236         return rn;
 237 }
 238
 239 protected int
 240 file_pipe2file(struct magic_set *ms, int fd, const void *startbuf,
 241     size_t nbytes)
 242 {
 243         char buf[4096];
 244         ssize_t r;
 245         int tfd, te;
 246
 247         (void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf);
 248 #ifndef HAVE_MKSTEMP
 249         {
 250                 char *ptr = mktemp(buf);
 251                 tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600);
 252                 r = errno;
 253                 (void)unlink(ptr);
 254                 errno = r;
 255         }
 256 #else
 257         tfd = mkstemp(buf);
 258         te = errno;
 259         (void)unlink(buf);
 260         errno = te;
 261 #endif
 262         if (tfd == -1) {
 263                 file_error(ms, errno,
 264                     "cannot create temporary file for pipe copy");
 265                 return -1;
 266         }
 267
 268         if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes)
 269                 r = 1;
 270         else {
 271                 while ((r = sread(fd, buf, sizeof(buf), 1)) > 0)
 272                         if (swrite(tfd, buf, (size_t)r) != r)
 273                                 break;
 274         }
 275
 276         switch (r) {
 277         case -1:
 278                 file_error(ms, errno, "error copying from pipe to temp file");
 279                 return -1;
 280         case 0:
 281                 break;
 282         default:
 283                 file_error(ms, errno, "error while writing to temp file");
 284                 return -1;
 285         }
 286
 287         /*
 288          * We duplicate the file descriptor, because fclose on a
 289          * tmpfile will delete the file, but any open descriptors
 290          * can still access the phantom inode.
 291          */
 292         if ((fd = dup2(tfd, fd)) == -1) {
 293                 file_error(ms, errno, "could not dup descriptor for temp file");
 294                 return -1;
 295         }
 296         (void)close(tfd);
 297         if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
 298                 file_badseek(ms);
 299                 return -1;
 300         }
 301         return fd;
 302 }
 303
 304 #ifdef BUILTIN_DECOMPRESS
 305
 306 #define FHCRC           (1 << 1)
 307 #define FEXTRA          (1 << 2)
 308 #define FNAME           (1 << 3)
 309 #define FCOMMENT        (1 << 4)
 310
 311 private size_t
 312 uncompressgzipped(struct magic_set *ms, const unsigned char *old,
 313     unsigned char **newch, size_t n)
 314 {
 315         unsigned char flg = old[3];
 316         size_t data_start = 10;
 317         z_stream z;
 318         int rc;
 319
 320         if (flg & FEXTRA) {
 321                 if (data_start+1 >= n)
 322                         return 0;
 323                 data_start += 2 + old[data_start] + old[data_start + 1] * 256;
 324         }
 325         if (flg & FNAME) {
 326                 while(data_start < n && old[data_start])
 327                         data_start++;
 328                 data_start++;
 329         }
 330         if(flg & FCOMMENT) {
 331                 while(data_start < n && old[data_start])
 332                         data_start++;
 333                 data_start++;
 334         }
 335         if(flg & FHCRC)
 336                 data_start += 2;
 337
 338         if (data_start >= n)
 339                 return 0;
 340         if ((*newch = CAST(unsigned char *, malloc(HOWMANY + 1))) == NULL) {
 341                 return 0;
 342         }
 343
 344         /* XXX: const castaway, via strchr */
 345         z.next_in = (Bytef *)strchr((const char *)old + data_start,
 346             old[data_start]);
 347         z.avail_in = CAST(uint32_t, (n - data_start));
 348         z.next_out = *newch;
 349         z.avail_out = HOWMANY;
 350         z.zalloc = Z_NULL;
 351         z.zfree = Z_NULL;
 352         z.opaque = Z_NULL;
 353
 354         /* LINTED bug in header macro */
 355         rc = inflateInit2(&z, -15);
 356         if (rc != Z_OK) {
 357                 file_error(ms, 0, "zlib: %s", z.msg);
 358                 return 0;
 359         }
 360
 361         rc = inflate(&z, Z_SYNC_FLUSH);
 362         if (rc != Z_OK && rc != Z_STREAM_END) {
 363                 file_error(ms, 0, "zlib: %s", z.msg);
 364                 return 0;
 365         }
 366
 367         n = (size_t)z.total_out;
 368         (void)inflateEnd(&z);
 369
 370         /* let's keep the nul-terminate tradition */
 371         (*newch)[n] = '\0';
 372
 373         return n;
 374 }
 375 #endif
 376
 377 private size_t
 378 uncompressbuf(struct magic_set *ms, int fd, size_t method,
 379     const unsigned char *old, unsigned char **newch, size_t n)
 380 {
 381         int fdin[2], fdout[2];
 382         ssize_t r;
 383
 384 #ifdef BUILTIN_DECOMPRESS
 385         /* FIXME: This doesn't cope with bzip2 */
 386         if (method == 2)
 387                 return uncompressgzipped(ms, old, newch, n);
 388 #endif
 389         (void)fflush(stdout);
 390         (void)fflush(stderr);
 391
 392         if ((fd != -1 && pipe(fdin) == -1) || pipe(fdout) == -1) {
 393                 file_error(ms, errno, "cannot create pipe");
 394                 return NODATA;
 395         }
 396         switch (fork()) {
 397         case 0: /* child */
 398                 (void) close(0);
 399                 if (fd != -1) {
 400                     (void) dup(fd);
 401                     (void) lseek(0, (off_t)0, SEEK_SET);
 402                 } else {
 403                     (void) dup(fdin[0]);
 404                     (void) close(fdin[0]);
 405                     (void) close(fdin[1]);
 406                 }
 407
 408                 (void) close(1);
 409                 (void) dup(fdout[1]);
 410                 (void) close(fdout[0]);
 411                 (void) close(fdout[1]);
 412 #ifndef DEBUG
 413                 if (compr[method].silent)
 414                         (void)close(2);
 415 #endif
 416
 417                 (void)execvp(compr[method].argv[0],
 418                     (char *const *)(intptr_t)compr[method].argv);
 419 #ifdef DEBUG
 420                 (void)fprintf(stderr, "exec `%s' failed (%s)\n",
 421                     compr[method].argv[0], strerror(errno));
 422 #endif
 423                 exit(1);
 424                 /*NOTREACHED*/
 425         case -1:
 426                 file_error(ms, errno, "could not fork");
 427                 return NODATA;
 428
 429         default: /* parent */
 430                 (void) close(fdout[1]);
 431                 if (fd == -1) {
 432                         (void) close(fdin[0]);
 433                         /*
 434                          * fork again, to avoid blocking because both
 435                          * pipes filled
 436                          */
 437                         switch (fork()) {
 438                         case 0: /* child */
 439                                 (void)close(fdout[0]);
 440                                 if (swrite(fdin[1], old, n) != (ssize_t)n) {
 441 #ifdef DEBUG
 442                                         (void)fprintf(stderr,
 443                                             "Write failed (%s)\n",
 444                                             strerror(errno));
 445 #endif
 446                                         exit(1);
 447                                 }
 448                                 exit(0);
 449                                 /*NOTREACHED*/
 450
 451                         case -1:
 452 #ifdef DEBUG
 453                                 (void)fprintf(stderr, "Fork failed (%s)\n",
 454                                     strerror(errno));
 455 #endif
 456                                 exit(1);
 457                                 /*NOTREACHED*/
 458
 459                         default:  /* parent */
 460                                 break;
 461                         }
 462                         (void) close(fdin[1]);
 463                         fdin[1] = -1;
 464                 }
 465
 466                 if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) {
 467 #ifdef DEBUG
 468                         (void)fprintf(stderr, "Malloc failed (%s)\n",
 469                             strerror(errno));
 470 #endif
 471                         n = 0;
 472                         goto err;
 473                 }
 474                 if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) {
 475 #ifdef DEBUG
 476                         (void)fprintf(stderr, "Read failed (%s)\n",
 477                             strerror(errno));
 478 #endif
 479                         free(*newch);
 480                         n = 0;
 481                         newch[0] = '\0';
 482                         goto err;
 483                 } else {
 484                         n = r;
 485                 }
 486                 /* NUL terminate, as every buffer is handled here. */
 487                 (*newch)[n] = '\0';
 488 err:
 489                 if (fdin[1] != -1)
 490                         (void) close(fdin[1]);
 491                 (void) close(fdout[0]);
 492 #ifdef WNOHANG
 493                 while (waitpid(-1, NULL, WNOHANG) != -1)
 494                         continue;
 495 #else
 496                 (void)wait(NULL);
 497 #endif
 498                 (void) close(fdin[0]);
 499
 500                 return n;
 501         }
 502 }