xref: /freebsd/contrib/file/src/compress.c (revision ea825d02749f382c3f7e17f28247f20a48733eab)
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
763