contrib/file/src/compress.c

   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 1.105 2017/05/25 00:13:03 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 #include <ctype.h>
  49 #include <stdarg.h>
  50 #ifdef HAVE_SIGNAL_H
  51 #include <signal.h>
  52 # ifndef HAVE_SIG_T
  53 typedef void (*sig_t)(int);
  54 # endif /* HAVE_SIG_T */
  55 #endif
  56 #if !defined(__MINGW32__) && !defined(WIN32)
  57 #include <sys/ioctl.h>
  58 #endif
  59 #ifdef HAVE_SYS_WAIT_H
  60 #include <sys/wait.h>
  61 #endif
  62 #if defined(HAVE_SYS_TIME_H)
  63 #include <sys/time.h>
  64 #endif
  65 #if defined(HAVE_ZLIB_H) && defined(ZLIBSUPPORT)
  66 #define BUILTIN_DECOMPRESS
  67 #include <zlib.h>
  68 #endif
  69 #ifdef DEBUG
  70 int tty = -1;
  71 #define DPRINTF(...)    do { \
  72         if (tty == -1) \
  73                 tty = open("/dev/tty", O_RDWR); \
  74         if (tty == -1) \
  75                 abort(); \
  76         dprintf(tty, __VA_ARGS__); \
  77 } while (/*CONSTCOND*/0)
  78 #else
  79 #define DPRINTF(...)
  80 #endif
  81
  82 #ifdef ZLIBSUPPORT
  83 /*
  84  * The following python code is not really used because ZLIBSUPPORT is only
  85  * defined if we have a built-in zlib, and the built-in zlib handles that.
  86  * That is not true for android where we have zlib.h and not -lz.
  87  */
  88 static const char zlibcode[] =
  89     "import sys, zlib; sys.stdout.write(zlib.decompress(sys.stdin.read()))";
  90
  91 static const char *zlib_args[] = { "python", "-c", zlibcode, NULL };
  92
  93 static int
  94 zlibcmp(const unsigned char *buf)
  95 {
  96         unsigned short x = 1;
  97         unsigned char *s = CAST(unsigned char *, CAST(void *, &x));
  98
  99         if ((buf[0] & 0xf) != 8 || (buf[0] & 0x80) != 0)
 100                 return 0;
 101         if (s[0] != 1)  /* endianness test */
 102                 x = buf[0] | (buf[1] << 8);
 103         else
 104                 x = buf[1] | (buf[0] << 8);
 105         if (x % 31)
 106                 return 0;
 107         return 1;
 108 }
 109 #endif
 110
 111 #define gzip_flags "-cd"
 112 #define lrzip_flags "-do"
 113 #define lzip_flags gzip_flags
 114
 115 static const char *gzip_args[] = {
 116         "gzip", gzip_flags, NULL
 117 };
 118 static const char *uncompress_args[] = {
 119         "uncompress", "-c", NULL
 120 };
 121 static const char *bzip2_args[] = {
 122         "bzip2", "-cd", NULL
 123 };
 124 static const char *lzip_args[] = {
 125         "lzip", lzip_flags, NULL
 126 };
 127 static const char *xz_args[] = {
 128         "xz", "-cd", NULL
 129 };
 130 static const char *lrzip_args[] = {
 131         "lrzip", lrzip_flags, NULL
 132 };
 133 static const char *lz4_args[] = {
 134         "lz4", "-cd", NULL
 135 };
 136 static const char *zstd_args[] = {
 137         "zstd", "-cd", NULL
 138 };
 139
 140 private const struct {
 141         const void *magic;
 142         size_t maglen;
 143         const char **argv;
 144 } compr[] = {
 145         { "\037\235",   2, gzip_args },         /* compressed */
 146         /* Uncompress can get stuck; so use gzip first if we have it
 147          * Idea from Damien Clark, thanks! */
 148         { "\037\235",   2, uncompress_args },   /* compressed */
 149         { "\037\213",   2, gzip_args },         /* gzipped */
 150         { "\037\236",   2, gzip_args },         /* frozen */
 151         { "\037\240",   2, gzip_args },         /* SCO LZH */
 152         /* the standard pack utilities do not accept standard input */
 153         { "\037\036",   2, gzip_args },         /* packed */
 154         { "PK\3\4",     4, gzip_args },         /* pkzipped, */
 155         /* ...only first file examined */
 156         { "BZh",        3, bzip2_args },        /* bzip2-ed */
 157         { "LZIP",       4, lzip_args },         /* lzip-ed */
 158         { "\3757zXZ\0", 6, xz_args },           /* XZ Utils */
 159         { "LRZI",       4, lrzip_args },        /* LRZIP */
 160         { "\004\"M\030",4, lz4_args },          /* LZ4 */
 161         { "\x28\xB5\x2F\xFD", 4, zstd_args },   /* zstd */
 162 #ifdef ZLIBSUPPORT
 163         { RCAST(const void *, zlibcmp), 0, zlib_args },         /* zlib */
 164 #endif
 165 };
 166
 167 #define OKDATA  0
 168 #define NODATA  1
 169 #define ERRDATA 2
 170
 171 private ssize_t swrite(int, const void *, size_t);
 172 #if HAVE_FORK
 173 private size_t ncompr = sizeof(compr) / sizeof(compr[0]);
 174 private int uncompressbuf(int, size_t, size_t, const unsigned char *,
 175     unsigned char **, size_t *);
 176 #ifdef BUILTIN_DECOMPRESS
 177 private int uncompresszlib(const unsigned char *, unsigned char **, size_t,
 178     size_t *, int);
 179 private int uncompressgzipped(const unsigned char *, unsigned char **, size_t,
 180     size_t *);
 181 #endif
 182 static int makeerror(unsigned char **, size_t *, const char *, ...)
 183     __attribute__((__format__(__printf__, 3, 4)));
 184 private const char *methodname(size_t);
 185
 186 protected int
 187 file_zmagic(struct magic_set *ms, int fd, const char *name,
 188     const unsigned char *buf, size_t nbytes)
 189 {
 190         unsigned char *newbuf = NULL;
 191         size_t i, nsz;
 192         char *rbuf;
 193         file_pushbuf_t *pb;
 194         int urv, prv, rv = 0;
 195         int mime = ms->flags & MAGIC_MIME;
 196 #ifdef HAVE_SIGNAL_H
 197         sig_t osigpipe;
 198 #endif
 199
 200         if ((ms->flags & MAGIC_COMPRESS) == 0)
 201                 return 0;
 202
 203 #ifdef HAVE_SIGNAL_H
 204         osigpipe = signal(SIGPIPE, SIG_IGN);
 205 #endif
 206         for (i = 0; i < ncompr; i++) {
 207                 int zm;
 208                 if (nbytes < compr[i].maglen)
 209                         continue;
 210 #ifdef ZLIBSUPPORT
 211                 if (compr[i].maglen == 0)
 212                         zm = (RCAST(int (*)(const unsigned char *),
 213                             CCAST(void *, compr[i].magic)))(buf);
 214                 else
 215 #endif
 216                         zm = memcmp(buf, compr[i].magic, compr[i].maglen) == 0;
 217
 218                 if (!zm)
 219                         continue;
 220                 nsz = nbytes;
 221                 urv = uncompressbuf(fd, ms->bytes_max, i, buf, &newbuf, &nsz);
 222                 DPRINTF("uncompressbuf = %d, %s, %zu\n", urv, (char *)newbuf,
 223                     nsz);
 224                 switch (urv) {
 225                 case OKDATA:
 226                 case ERRDATA:
 227
 228                         ms->flags &= ~MAGIC_COMPRESS;
 229                         if (urv == ERRDATA)
 230                                 prv = file_printf(ms, "%s ERROR: %s",
 231                                     methodname(i), newbuf);
 232                         else
 233                                 prv = file_buffer(ms, -1, name, newbuf, nsz);
 234                         if (prv == -1)
 235                                 goto error;
 236                         rv = 1;
 237                         if ((ms->flags & MAGIC_COMPRESS_TRANSP) != 0)
 238                                 goto out;
 239                         if (mime != MAGIC_MIME && mime != 0)
 240                                 goto out;
 241                         if ((file_printf(ms,
 242                             mime ? " compressed-encoding=" : " (")) == -1)
 243                                 goto error;
 244                         if ((pb = file_push_buffer(ms)) == NULL)
 245                                 goto error;
 246                         /*
 247                          * XXX: If file_buffer fails here, we overwrite
 248                          * the compressed text. FIXME.
 249                          */
 250                         if (file_buffer(ms, -1, NULL, buf, nbytes) == -1)
 251                                 goto error;
 252                         if ((rbuf = file_pop_buffer(ms, pb)) != NULL) {
 253                                 if (file_printf(ms, "%s", rbuf) == -1) {
 254                                         free(rbuf);
 255                                         goto error;
 256                                 }
 257                                 free(rbuf);
 258                         }
 259                         if (!mime && file_printf(ms, ")") == -1)
 260                                 goto error;
 261                         /*FALLTHROUGH*/
 262                 case NODATA:
 263                         break;
 264                 default:
 265                         abort();
 266                         /*NOTREACHED*/
 267                 error:
 268                         rv = -1;
 269                         break;
 270                 }
 271         }
 272 out:
 273         DPRINTF("rv = %d\n", rv);
 274
 275 #ifdef HAVE_SIGNAL_H
 276         (void)signal(SIGPIPE, osigpipe);
 277 #endif
 278         free(newbuf);
 279         ms->flags |= MAGIC_COMPRESS;
 280         DPRINTF("Zmagic returns %d\n", rv);
 281         return rv;
 282 }
 283 #endif
 284 /*
 285  * `safe' write for sockets and pipes.
 286  */
 287 private ssize_t
 288 swrite(int fd, const void *buf, size_t n)
 289 {
 290         ssize_t rv;
 291         size_t rn = n;
 292
 293         do
 294                 switch (rv = write(fd, buf, n)) {
 295                 case -1:
 296                         if (errno == EINTR)
 297                                 continue;
 298                         return -1;
 299                 default:
 300                         n -= rv;
 301                         buf = CAST(const char *, buf) + rv;
 302                         break;
 303                 }
 304         while (n > 0);
 305         return rn;
 306 }
 307
 308
 309 /*
 310  * `safe' read for sockets and pipes.
 311  */
 312 protected ssize_t
 313 sread(int fd, void *buf, size_t n, int canbepipe __attribute__((__unused__)))
 314 {
 315         ssize_t rv;
 316 #ifdef FIONREAD
 317         int t = 0;
 318 #endif
 319         size_t rn = n;
 320
 321         if (fd == STDIN_FILENO)
 322                 goto nocheck;
 323
 324 #ifdef FIONREAD
 325         if (canbepipe && (ioctl(fd, FIONREAD, &t) == -1 || t == 0)) {
 326 #ifdef FD_ZERO
 327                 ssize_t cnt;
 328                 for (cnt = 0;; cnt++) {
 329                         fd_set check;
 330                         struct timeval tout = {0, 100 * 1000};
 331                         int selrv;
 332
 333                         FD_ZERO(&check);
 334                         FD_SET(fd, &check);
 335
 336                         /*
 337                          * Avoid soft deadlock: do not read if there
 338                          * is nothing to read from sockets and pipes.
 339                          */
 340                         selrv = select(fd + 1, &check, NULL, NULL, &tout);
 341                         if (selrv == -1) {
 342                                 if (errno == EINTR || errno == EAGAIN)
 343                                         continue;
 344                         } else if (selrv == 0 && cnt >= 5) {
 345                                 return 0;
 346                         } else
 347                                 break;
 348                 }
 349 #endif
 350                 (void)ioctl(fd, FIONREAD, &t);
 351         }
 352
 353         if (t > 0 && (size_t)t < n) {
 354                 n = t;
 355                 rn = n;
 356         }
 357 #endif
 358
 359 nocheck:
 360         do
 361                 switch ((rv = read(fd, buf, n))) {
 362                 case -1:
 363                         if (errno == EINTR)
 364                                 continue;
 365                         return -1;
 366                 case 0:
 367                         return rn - n;
 368                 default:
 369                         n -= rv;
 370                         buf = CAST(char *, CCAST(void *, buf)) + rv;
 371                         break;
 372                 }
 373         while (n > 0);
 374         return rn;
 375 }
 376
 377 protected int
 378 file_pipe2file(struct magic_set *ms, int fd, const void *startbuf,
 379     size_t nbytes)
 380 {
 381         char buf[4096];
 382         ssize_t r;
 383         int tfd;
 384
 385         (void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf);
 386 #ifndef HAVE_MKSTEMP
 387         {
 388                 char *ptr = mktemp(buf);
 389                 tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600);
 390                 r = errno;
 391                 (void)unlink(ptr);
 392                 errno = r;
 393         }
 394 #else
 395         {
 396                 int te;
 397                 tfd = mkstemp(buf);
 398                 te = errno;
 399                 (void)unlink(buf);
 400                 errno = te;
 401         }
 402 #endif
 403         if (tfd == -1) {
 404                 file_error(ms, errno,
 405                     "cannot create temporary file for pipe copy");
 406                 return -1;
 407         }
 408
 409         if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes)
 410                 r = 1;
 411         else {
 412                 while ((r = sread(fd, buf, sizeof(buf), 1)) > 0)
 413                         if (swrite(tfd, buf, (size_t)r) != r)
 414                                 break;
 415         }
 416
 417         switch (r) {
 418         case -1:
 419                 file_error(ms, errno, "error copying from pipe to temp file");
 420                 return -1;
 421         case 0:
 422                 break;
 423         default:
 424                 file_error(ms, errno, "error while writing to temp file");
 425                 return -1;
 426         }
 427
 428         /*
 429          * We duplicate the file descriptor, because fclose on a
 430          * tmpfile will delete the file, but any open descriptors
 431          * can still access the phantom inode.
 432          */
 433         if ((fd = dup2(tfd, fd)) == -1) {
 434                 file_error(ms, errno, "could not dup descriptor for temp file");
 435                 return -1;
 436         }
 437         (void)close(tfd);
 438         if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
 439                 file_badseek(ms);
 440                 return -1;
 441         }
 442         return fd;
 443 }
 444 #if HAVE_FORK
 445 #ifdef BUILTIN_DECOMPRESS
 446
 447 #define FHCRC           (1 << 1)
 448 #define FEXTRA          (1 << 2)
 449 #define FNAME           (1 << 3)
 450 #define FCOMMENT        (1 << 4)
 451
 452
 453 private int
 454 uncompressgzipped(const unsigned char *old, unsigned char **newch,
 455     size_t bytes_max, size_t *n)
 456 {
 457         unsigned char flg = old[3];
 458         size_t data_start = 10;
 459
 460         if (flg & FEXTRA) {
 461                 if (data_start + 1 >= *n)
 462                         goto err;
 463                 data_start += 2 + old[data_start] + old[data_start + 1] * 256;
 464         }
 465         if (flg & FNAME) {
 466                 while(data_start < *n && old[data_start])
 467                         data_start++;
 468                 data_start++;
 469         }
 470         if (flg & FCOMMENT) {
 471                 while(data_start < *n && old[data_start])
 472                         data_start++;
 473                 data_start++;
 474         }
 475         if (flg & FHCRC)
 476                 data_start += 2;
 477
 478         if (data_start >= *n)
 479                 goto err;
 480
 481         *n -= data_start;
 482         old += data_start;
 483         return uncompresszlib(old, newch, bytes_max, n, 0);
 484 err:
 485         return makeerror(newch, n, "File too short");
 486 }
 487
 488 private int
 489 uncompresszlib(const unsigned char *old, unsigned char **newch,
 490     size_t bytes_max, size_t *n, int zlib)
 491 {
 492         int rc;
 493         z_stream z;
 494
 495         if ((*newch = CAST(unsigned char *, malloc(bytes_max + 1))) == NULL)
 496                 return makeerror(newch, n, "No buffer, %s", strerror(errno));
 497
 498         z.next_in = CCAST(Bytef *, old);
 499         z.avail_in = CAST(uint32_t, *n);
 500         z.next_out = *newch;
 501         z.avail_out = CAST(unsigned int, bytes_max);
 502         z.zalloc = Z_NULL;
 503         z.zfree = Z_NULL;
 504         z.opaque = Z_NULL;
 505
 506         /* LINTED bug in header macro */
 507         rc = zlib ? inflateInit(&z) : inflateInit2(&z, -15);
 508         if (rc != Z_OK)
 509                 goto err;
 510
 511         rc = inflate(&z, Z_SYNC_FLUSH);
 512         if (rc != Z_OK && rc != Z_STREAM_END)
 513                 goto err;
 514
 515         *n = (size_t)z.total_out;
 516         rc = inflateEnd(&z);
 517         if (rc != Z_OK)
 518                 goto err;
 519
 520         /* let's keep the nul-terminate tradition */
 521         (*newch)[*n] = '\0';
 522
 523         return OKDATA;
 524 err:
 525         strlcpy((char *)*newch, z.msg ? z.msg : zError(rc), bytes_max);
 526         *n = strlen((char *)*newch);
 527         return ERRDATA;
 528 }
 529 #endif
 530
 531 static int
 532 makeerror(unsigned char **buf, size_t *len, const char *fmt, ...)
 533 {
 534         char *msg;
 535         va_list ap;
 536         int rv;
 537
 538         va_start(ap, fmt);
 539         rv = vasprintf(&msg, fmt, ap);
 540         va_end(ap);
 541         if (rv < 0) {
 542                 *buf = NULL;
 543                 *len = 0;
 544                 return NODATA;
 545         }
 546         *buf = (unsigned char *)msg;
 547         *len = strlen(msg);
 548         return ERRDATA;
 549 }
 550
 551 static void
 552 closefd(int *fd, size_t i)
 553 {
 554         if (fd[i] == -1)
 555                 return;
 556         (void) close(fd[i]);
 557         fd[i] = -1;
 558 }
 559
 560 static void
 561 closep(int *fd)
 562 {
 563         size_t i;
 564         for (i = 0; i < 2; i++)
 565                 closefd(fd, i);
 566 }
 567
 568 static void
 569 copydesc(int i, int *fd)
 570 {
 571         int j = fd[i == STDIN_FILENO ? 0 : 1];
 572         if (j == i)
 573                 return;
 574         if (dup2(j, i) == -1) {
 575                 DPRINTF("dup(%d, %d) failed (%s)\n", j, i, strerror(errno));
 576                 exit(1);
 577         }
 578         closep(fd);
 579 }
 580
 581 static void
 582 writechild(int fdp[3][2], const void *old, size_t n)
 583 {
 584         int status;
 585
 586         closefd(fdp[STDIN_FILENO], 0);
 587         /*
 588          * fork again, to avoid blocking because both
 589          * pipes filled
 590          */
 591         switch (fork()) {
 592         case 0: /* child */
 593                 closefd(fdp[STDOUT_FILENO], 0);
 594                 if (swrite(fdp[STDIN_FILENO][1], old, n) != (ssize_t)n) {
 595                         DPRINTF("Write failed (%s)\n", strerror(errno));
 596                         exit(1);
 597                 }
 598                 exit(0);
 599                 /*NOTREACHED*/
 600
 601         case -1:
 602                 DPRINTF("Fork failed (%s)\n", strerror(errno));
 603                 exit(1);
 604                 /*NOTREACHED*/
 605
 606         default:  /* parent */
 607                 if (wait(&status) == -1) {
 608                         DPRINTF("Wait failed (%s)\n", strerror(errno));
 609                         exit(1);
 610                 }
 611                 DPRINTF("Grandchild wait return %#x\n", status);
 612         }
 613         closefd(fdp[STDIN_FILENO], 1);
 614 }
 615
 616 static ssize_t
 617 filter_error(unsigned char *ubuf, ssize_t n)
 618 {
 619         char *p;
 620         char *buf;
 621
 622         ubuf[n] = '\0';
 623         buf = (char *)ubuf;
 624         while (isspace((unsigned char)*buf))
 625                 buf++;
 626         DPRINTF("Filter error[[[%s]]]\n", buf);
 627         if ((p = strchr((char *)buf, '\n')) != NULL)
 628                 *p = '\0';
 629         if ((p = strchr((char *)buf, ';')) != NULL)
 630                 *p = '\0';
 631         if ((p = strrchr((char *)buf, ':')) != NULL) {
 632                 ++p;
 633                 while (isspace((unsigned char)*p))
 634                         p++;
 635                 n = strlen(p);
 636                 memmove(ubuf, p, CAST(size_t, n + 1));
 637         }
 638         DPRINTF("Filter error after[[[%s]]]\n", (char *)ubuf);
 639         if (islower(*ubuf))
 640                 *ubuf = toupper(*ubuf);
 641         return n;
 642 }
 643
 644 private const char *
 645 methodname(size_t method)
 646 {
 647 #ifdef BUILTIN_DECOMPRESS
 648         /* FIXME: This doesn't cope with bzip2 */
 649         if (method == 2 || compr[method].maglen == 0)
 650             return "zlib";
 651 #endif
 652         return compr[method].argv[0];
 653 }
 654
 655 private int
 656 uncompressbuf(int fd, size_t bytes_max, size_t method, const unsigned char *old,
 657     unsigned char **newch, size_t* n)
 658 {
 659         int fdp[3][2];
 660         int status, rv;
 661         size_t i;
 662         ssize_t r;
 663
 664 #ifdef BUILTIN_DECOMPRESS
 665         /* FIXME: This doesn't cope with bzip2 */
 666         if (method == 2)
 667                 return uncompressgzipped(old, newch, bytes_max, n);
 668         if (compr[method].maglen == 0)
 669                 return uncompresszlib(old, newch, bytes_max, n, 1);
 670 #endif
 671         (void)fflush(stdout);
 672         (void)fflush(stderr);
 673
 674         for (i = 0; i < __arraycount(fdp); i++)
 675                 fdp[i][0] = fdp[i][1] = -1;
 676
 677         if ((fd == -1 && pipe(fdp[STDIN_FILENO]) == -1) ||
 678             pipe(fdp[STDOUT_FILENO]) == -1 || pipe(fdp[STDERR_FILENO]) == -1) {
 679                 closep(fdp[STDIN_FILENO]);
 680                 closep(fdp[STDOUT_FILENO]);
 681                 return makeerror(newch, n, "Cannot create pipe, %s",
 682                     strerror(errno));
 683         }
 684         switch (fork()) {
 685         case 0: /* child */
 686                 if (fd != -1) {
 687                         fdp[STDIN_FILENO][0] = fd;
 688                         (void) lseek(fd, (off_t)0, SEEK_SET);
 689                 }
 690
 691                 for (i = 0; i < __arraycount(fdp); i++)
 692                         copydesc(CAST(int, i), fdp[i]);
 693
 694                 (void)execvp(compr[method].argv[0],
 695                     (char *const *)(intptr_t)compr[method].argv);
 696                 dprintf(STDERR_FILENO, "exec `%s' failed, %s",
 697                     compr[method].argv[0], strerror(errno));
 698                 exit(1);
 699                 /*NOTREACHED*/
 700         case -1:
 701                 return makeerror(newch, n, "Cannot fork, %s",
 702                     strerror(errno));
 703
 704         default: /* parent */
 705                 for (i = 1; i < __arraycount(fdp); i++)
 706                         closefd(fdp[i], 1);
 707
 708                 /* Write the buffer data to the child, if we don't have fd */
 709                 if (fd == -1)
 710                         writechild(fdp, old, *n);
 711
 712                 *newch = CAST(unsigned char *, malloc(bytes_max + 1));
 713                 if (*newch == NULL) {
 714                         rv = makeerror(newch, n, "No buffer, %s",
 715                             strerror(errno));
 716                         goto err;
 717                 }
 718                 rv = OKDATA;
 719                 if ((r = sread(fdp[STDOUT_FILENO][0], *newch, bytes_max, 0)) > 0)
 720                         break;
 721                 DPRINTF("Read stdout failed %d (%s)\n", fdp[STDOUT_FILENO][0],
 722                     r != -1 ? strerror(errno) : "no data");
 723
 724                 rv = ERRDATA;
 725                 if (r == 0 &&
 726                     (r = sread(fdp[STDERR_FILENO][0], *newch, bytes_max, 0)) > 0)
 727                 {
 728                         r = filter_error(*newch, r);
 729                         break;
 730                 }
 731                 free(*newch);
 732                 if  (r == 0)
 733                         rv = makeerror(newch, n, "Read failed, %s",
 734                             strerror(errno));
 735                 else
 736                         rv = makeerror(newch, n, "No data");
 737                 goto err;
 738         }
 739
 740         *n = r;
 741         /* NUL terminate, as every buffer is handled here. */
 742         (*newch)[*n] = '\0';
 743 err:
 744         closefd(fdp[STDIN_FILENO], 1);
 745         closefd(fdp[STDOUT_FILENO], 0);
 746         closefd(fdp[STDERR_FILENO], 0);
 747         if (wait(&status) == -1) {
 748                 free(*newch);
 749                 rv = makeerror(newch, n, "Wait failed, %s", strerror(errno));
 750                 DPRINTF("Child wait return %#x\n", status);
 751         } else if (!WIFEXITED(status)) {
 752                 DPRINTF("Child not exited (%#x)\n", status);
 753         } else if (WEXITSTATUS(status) != 0) {
 754                 DPRINTF("Child exited (%#x)\n", WEXITSTATUS(status));
 755         }
 756
 757         closefd(fdp[STDIN_FILENO], 0);
 758         DPRINTF("Returning %p n=%zu rv=%d\n", *newch, *n, rv);
 759
 760         return rv;
 761 }
 762 #endif