xref: /freebsd/contrib/file/src/compress.c (revision 18849b5da0c5eaa88500b457be05b038813b51b1)
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 1.96 2016/04/20 00:00:26 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(HAVE_LIBZ)
66 #define BUILTIN_DECOMPRESS
67 #include <zlib.h>
68 #define ZLIBSUPPORT
69 #endif
70 #ifdef DEBUG
71 int tty = -1;
72 #define DPRINTF(...)	do { \
73 	if (tty == -1) \
74 		tty = open("/dev/tty", O_RDWR); \
75 	if (tty == -1) \
76 		abort(); \
77 	dprintf(tty, __VA_ARGS__); \
78 } while (/*CONSTCOND*/0)
79 #else
80 #define DPRINTF(...)
81 #endif
82 
83 #ifdef ZLIBSUPPORT
84 /*
85  * The following python code is not really used because ZLIBSUPPORT is only
86  * defined if we have a built-in zlib, and the built-in zlib handles that.
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 = (unsigned char *)&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 
137 private const struct {
138 	const void *magic;
139 	size_t maglen;
140 	const char **argv;
141 } compr[] = {
142 	{ "\037\235",	2, gzip_args },		/* compressed */
143 	/* Uncompress can get stuck; so use gzip first if we have it
144 	 * Idea from Damien Clark, thanks! */
145 	{ "\037\235",	2, uncompress_args },	/* compressed */
146 	{ "\037\213",	2, gzip_args },		/* gzipped */
147 	{ "\037\236",	2, gzip_args },		/* frozen */
148 	{ "\037\240",	2, gzip_args },		/* SCO LZH */
149 	/* the standard pack utilities do not accept standard input */
150 	{ "\037\036",	2, gzip_args },		/* packed */
151 	{ "PK\3\4",	4, gzip_args },		/* pkzipped, */
152 	/* ...only first file examined */
153 	{ "BZh",	3, bzip2_args },	/* bzip2-ed */
154 	{ "LZIP",	4, lzip_args },		/* lzip-ed */
155  	{ "\3757zXZ\0",	6, xz_args },		/* XZ Utils */
156  	{ "LRZI",	4, lrzip_args },	/* LRZIP */
157  	{ "\004\"M\030",4, lz4_args },		/* LZ4 */
158 #ifdef ZLIBSUPPORT
159 	{ zlibcmp,	0, zlib_args },		/* zlib */
160 #endif
161 };
162 
163 #define OKDATA 	0
164 #define NODATA	1
165 #define ERRDATA	2
166 
167 private ssize_t swrite(int, const void *, size_t);
168 #if HAVE_FORK
169 private size_t ncompr = sizeof(compr) / sizeof(compr[0]);
170 private int uncompressbuf(int, size_t, size_t, const unsigned char *,
171     unsigned char **, size_t *);
172 #ifdef BUILTIN_DECOMPRESS
173 private int uncompresszlib(const unsigned char *, unsigned char **, size_t,
174     size_t *, int);
175 private int uncompressgzipped(const unsigned char *, unsigned char **, size_t,
176     size_t *);
177 #endif
178 static int makeerror(unsigned char **, size_t *, const char *, ...)
179     __attribute__((__format__(__printf__, 3, 4)));
180 private const char *methodname(size_t);
181 
182 protected int
183 file_zmagic(struct magic_set *ms, int fd, const char *name,
184     const unsigned char *buf, size_t nbytes)
185 {
186 	unsigned char *newbuf = NULL;
187 	size_t i, nsz;
188 	char *rbuf;
189 	file_pushbuf_t *pb;
190 	int urv, prv, rv = 0;
191 	int mime = ms->flags & MAGIC_MIME;
192 #ifdef HAVE_SIGNAL_H
193 	sig_t osigpipe;
194 #endif
195 
196 	if ((ms->flags & MAGIC_COMPRESS) == 0)
197 		return 0;
198 
199 #ifdef HAVE_SIGNAL_H
200 	osigpipe = signal(SIGPIPE, SIG_IGN);
201 #endif
202 	for (i = 0; i < ncompr; i++) {
203 		int zm;
204 		if (nbytes < compr[i].maglen)
205 			continue;
206 #ifdef ZLIBSUPPORT
207 		if (compr[i].maglen == 0)
208 			zm = (CAST(int (*)(const unsigned char *),
209 			    CCAST(void *, compr[i].magic)))(buf);
210 		else
211 #endif
212 			zm = memcmp(buf, compr[i].magic, compr[i].maglen) == 0;
213 
214 		if (!zm)
215 			continue;
216 		nsz = nbytes;
217 		urv = uncompressbuf(fd, ms->bytes_max, i, buf, &newbuf, &nsz);
218 		DPRINTF("uncompressbuf = %d, %s, %zu\n", urv, (char *)newbuf,
219 		    nsz);
220 		switch (urv) {
221 		case OKDATA:
222 		case ERRDATA:
223 
224 			ms->flags &= ~MAGIC_COMPRESS;
225 			if (urv == ERRDATA)
226 				prv = file_printf(ms, "%s ERROR: %s",
227 				    methodname(i), newbuf);
228 			else
229 				prv = file_buffer(ms, -1, name, newbuf, nsz);
230 			if (prv == -1)
231 				goto error;
232 			rv = 1;
233 			if ((ms->flags & MAGIC_COMPRESS_TRANSP) != 0)
234 				goto out;
235 			if (mime != MAGIC_MIME && mime != 0)
236 				goto out;
237 			if ((file_printf(ms,
238 			    mime ? " compressed-encoding=" : " (")) == -1)
239 				goto error;
240 			if ((pb = file_push_buffer(ms)) == NULL)
241 				goto error;
242 			/*
243 			 * XXX: If file_buffer fails here, we overwrite
244 			 * the compressed text. FIXME.
245 			 */
246 			if (file_buffer(ms, -1, NULL, buf, nbytes) == -1)
247 				goto error;
248 			if ((rbuf = file_pop_buffer(ms, pb)) != NULL) {
249 				if (file_printf(ms, "%s", rbuf) == -1) {
250 					free(rbuf);
251 					goto error;
252 				}
253 				free(rbuf);
254 			}
255 			if (!mime && file_printf(ms, ")") == -1)
256 				goto error;
257 			/*FALLTHROUGH*/
258 		case NODATA:
259 			break;
260 		default:
261 			abort();
262 			/*NOTREACHED*/
263 		error:
264 			rv = -1;
265 			break;
266 		}
267 	}
268 out:
269 	DPRINTF("rv = %d\n", rv);
270 
271 #ifdef HAVE_SIGNAL_H
272 	(void)signal(SIGPIPE, osigpipe);
273 #endif
274 	free(newbuf);
275 	ms->flags |= MAGIC_COMPRESS;
276 	DPRINTF("Zmagic returns %d\n", rv);
277 	return rv;
278 }
279 #endif
280 /*
281  * `safe' write for sockets and pipes.
282  */
283 private ssize_t
284 swrite(int fd, const void *buf, size_t n)
285 {
286 	ssize_t rv;
287 	size_t rn = n;
288 
289 	do
290 		switch (rv = write(fd, buf, n)) {
291 		case -1:
292 			if (errno == EINTR)
293 				continue;
294 			return -1;
295 		default:
296 			n -= rv;
297 			buf = CAST(const char *, buf) + rv;
298 			break;
299 		}
300 	while (n > 0);
301 	return rn;
302 }
303 
304 
305 /*
306  * `safe' read for sockets and pipes.
307  */
308 protected ssize_t
309 sread(int fd, void *buf, size_t n, int canbepipe __attribute__((__unused__)))
310 {
311 	ssize_t rv;
312 #ifdef FIONREAD
313 	int t = 0;
314 #endif
315 	size_t rn = n;
316 
317 	if (fd == STDIN_FILENO)
318 		goto nocheck;
319 
320 #ifdef FIONREAD
321 	if (canbepipe && (ioctl(fd, FIONREAD, &t) == -1 || t == 0)) {
322 #ifdef FD_ZERO
323 		ssize_t cnt;
324 		for (cnt = 0;; cnt++) {
325 			fd_set check;
326 			struct timeval tout = {0, 100 * 1000};
327 			int selrv;
328 
329 			FD_ZERO(&check);
330 			FD_SET(fd, &check);
331 
332 			/*
333 			 * Avoid soft deadlock: do not read if there
334 			 * is nothing to read from sockets and pipes.
335 			 */
336 			selrv = select(fd + 1, &check, NULL, NULL, &tout);
337 			if (selrv == -1) {
338 				if (errno == EINTR || errno == EAGAIN)
339 					continue;
340 			} else if (selrv == 0 && cnt >= 5) {
341 				return 0;
342 			} else
343 				break;
344 		}
345 #endif
346 		(void)ioctl(fd, FIONREAD, &t);
347 	}
348 
349 	if (t > 0 && (size_t)t < n) {
350 		n = t;
351 		rn = n;
352 	}
353 #endif
354 
355 nocheck:
356 	do
357 		switch ((rv = read(fd, buf, n))) {
358 		case -1:
359 			if (errno == EINTR)
360 				continue;
361 			return -1;
362 		case 0:
363 			return rn - n;
364 		default:
365 			n -= rv;
366 			buf = ((char *)buf) + rv;
367 			break;
368 		}
369 	while (n > 0);
370 	return rn;
371 }
372 
373 protected int
374 file_pipe2file(struct magic_set *ms, int fd, const void *startbuf,
375     size_t nbytes)
376 {
377 	char buf[4096];
378 	ssize_t r;
379 	int tfd;
380 
381 	(void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf);
382 #ifndef HAVE_MKSTEMP
383 	{
384 		char *ptr = mktemp(buf);
385 		tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600);
386 		r = errno;
387 		(void)unlink(ptr);
388 		errno = r;
389 	}
390 #else
391 	{
392 		int te;
393 		tfd = mkstemp(buf);
394 		te = errno;
395 		(void)unlink(buf);
396 		errno = te;
397 	}
398 #endif
399 	if (tfd == -1) {
400 		file_error(ms, errno,
401 		    "cannot create temporary file for pipe copy");
402 		return -1;
403 	}
404 
405 	if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes)
406 		r = 1;
407 	else {
408 		while ((r = sread(fd, buf, sizeof(buf), 1)) > 0)
409 			if (swrite(tfd, buf, (size_t)r) != r)
410 				break;
411 	}
412 
413 	switch (r) {
414 	case -1:
415 		file_error(ms, errno, "error copying from pipe to temp file");
416 		return -1;
417 	case 0:
418 		break;
419 	default:
420 		file_error(ms, errno, "error while writing to temp file");
421 		return -1;
422 	}
423 
424 	/*
425 	 * We duplicate the file descriptor, because fclose on a
426 	 * tmpfile will delete the file, but any open descriptors
427 	 * can still access the phantom inode.
428 	 */
429 	if ((fd = dup2(tfd, fd)) == -1) {
430 		file_error(ms, errno, "could not dup descriptor for temp file");
431 		return -1;
432 	}
433 	(void)close(tfd);
434 	if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
435 		file_badseek(ms);
436 		return -1;
437 	}
438 	return fd;
439 }
440 #if HAVE_FORK
441 #ifdef BUILTIN_DECOMPRESS
442 
443 #define FHCRC		(1 << 1)
444 #define FEXTRA		(1 << 2)
445 #define FNAME		(1 << 3)
446 #define FCOMMENT	(1 << 4)
447 
448 
449 private int
450 uncompressgzipped(const unsigned char *old, unsigned char **newch,
451     size_t bytes_max, size_t *n)
452 {
453 	unsigned char flg = old[3];
454 	size_t data_start = 10;
455 
456 	if (flg & FEXTRA) {
457 		if (data_start + 1 >= *n)
458 			goto err;
459 		data_start += 2 + old[data_start] + old[data_start + 1] * 256;
460 	}
461 	if (flg & FNAME) {
462 		while(data_start < *n && old[data_start])
463 			data_start++;
464 		data_start++;
465 	}
466 	if (flg & FCOMMENT) {
467 		while(data_start < *n && old[data_start])
468 			data_start++;
469 		data_start++;
470 	}
471 	if (flg & FHCRC)
472 		data_start += 2;
473 
474 	if (data_start >= *n)
475 		goto err;
476 
477 	*n -= data_start;
478 	old += data_start;
479 	return uncompresszlib(old, newch, bytes_max, n, 0);
480 err:
481 	return makeerror(newch, n, "File too short");
482 }
483 
484 private int
485 uncompresszlib(const unsigned char *old, unsigned char **newch,
486     size_t bytes_max, size_t *n, int zlib)
487 {
488 	int rc;
489 	z_stream z;
490 
491 	if ((*newch = CAST(unsigned char *, malloc(bytes_max + 1))) == NULL)
492 		return makeerror(newch, n, "No buffer, %s", strerror(errno));
493 
494 	z.next_in = CCAST(Bytef *, old);
495 	z.avail_in = CAST(uint32_t, *n);
496 	z.next_out = *newch;
497 	z.avail_out = bytes_max;
498 	z.zalloc = Z_NULL;
499 	z.zfree = Z_NULL;
500 	z.opaque = Z_NULL;
501 
502 	/* LINTED bug in header macro */
503 	rc = zlib ? inflateInit(&z) : inflateInit2(&z, -15);
504 	if (rc != Z_OK)
505 		goto err;
506 
507 	rc = inflate(&z, Z_SYNC_FLUSH);
508 	if (rc != Z_OK && rc != Z_STREAM_END)
509 		goto err;
510 
511 	*n = (size_t)z.total_out;
512 	rc = inflateEnd(&z);
513 	if (rc != Z_OK)
514 		goto err;
515 
516 	/* let's keep the nul-terminate tradition */
517 	(*newch)[*n] = '\0';
518 
519 	return OKDATA;
520 err:
521 	strlcpy((char *)*newch, z.msg, bytes_max);
522 	*n = strlen((char *)*newch);
523 	return ERRDATA;
524 }
525 #endif
526 
527 static int
528 makeerror(unsigned char **buf, size_t *len, const char *fmt, ...)
529 {
530 	char *msg;
531 	va_list ap;
532 	int rv;
533 
534 	va_start(ap, fmt);
535 	rv = vasprintf(&msg, fmt, ap);
536 	va_end(ap);
537 	if (rv < 0) {
538 		*buf = NULL;
539 		*len = 0;
540 		return NODATA;
541 	}
542 	*buf = (unsigned char *)msg;
543 	*len = strlen(msg);
544 	return ERRDATA;
545 }
546 
547 static void
548 closefd(int *fd, size_t i)
549 {
550 	if (fd[i] == -1)
551 		return;
552 	(void) close(fd[i]);
553 	fd[i] = -1;
554 }
555 
556 static void
557 closep(int *fd)
558 {
559 	size_t i;
560 	for (i = 0; i < 2; i++)
561 		closefd(fd, i);
562 }
563 
564 static void
565 copydesc(int i, int *fd)
566 {
567 	int j = fd[i == STDIN_FILENO ? 0 : 1];
568 	if (j == i)
569 		return;
570 	if (dup2(j, i) == -1) {
571 		DPRINTF("dup(%d, %d) failed (%s)\n", j, i, strerror(errno));
572 		exit(1);
573 	}
574 	closep(fd);
575 }
576 
577 static void
578 writechild(int fdp[3][2], const void *old, size_t n)
579 {
580 	int status;
581 
582 	closefd(fdp[STDIN_FILENO], 0);
583 	/*
584 	 * fork again, to avoid blocking because both
585 	 * pipes filled
586 	 */
587 	switch (fork()) {
588 	case 0: /* child */
589 		closefd(fdp[STDOUT_FILENO], 0);
590 		if (swrite(fdp[STDIN_FILENO][1], old, n) != (ssize_t)n) {
591 			DPRINTF("Write failed (%s)\n", strerror(errno));
592 			exit(1);
593 		}
594 		exit(0);
595 		/*NOTREACHED*/
596 
597 	case -1:
598 		DPRINTF("Fork failed (%s)\n", strerror(errno));
599 		exit(1);
600 		/*NOTREACHED*/
601 
602 	default:  /* parent */
603 		if (wait(&status) == -1) {
604 			DPRINTF("Wait failed (%s)\n", strerror(errno));
605 			exit(1);
606 		}
607 		DPRINTF("Grandchild wait return %#x\n", status);
608 	}
609 	closefd(fdp[STDIN_FILENO], 1);
610 }
611 
612 static ssize_t
613 filter_error(unsigned char *ubuf, ssize_t n)
614 {
615 	char *p;
616 	char *buf;
617 
618 	ubuf[n] = '\0';
619 	buf = (char *)ubuf;
620 	while (isspace((unsigned char)*buf))
621 		buf++;
622 	DPRINTF("Filter error[[[%s]]]\n", buf);
623 	if ((p = strchr((char *)buf, '\n')) != NULL)
624 		*p = '\0';
625 	if ((p = strchr((char *)buf, ';')) != NULL)
626 		*p = '\0';
627 	if ((p = strrchr((char *)buf, ':')) != NULL) {
628 		++p;
629 		while (isspace((unsigned char)*p))
630 			p++;
631 		n = strlen(p);
632 		memmove(ubuf, p, n + 1);
633 	}
634 	DPRINTF("Filter error after[[[%s]]]\n", (char *)ubuf);
635 	if (islower(*ubuf))
636 		*ubuf = toupper(*ubuf);
637 	return n;
638 }
639 
640 private const char *
641 methodname(size_t method)
642 {
643 #ifdef BUILTIN_DECOMPRESS
644         /* FIXME: This doesn't cope with bzip2 */
645 	if (method == 2 || compr[method].maglen == 0)
646 	    return "zlib";
647 #endif
648 	return compr[method].argv[0];
649 }
650 
651 private int
652 uncompressbuf(int fd, size_t bytes_max, size_t method, const unsigned char *old,
653     unsigned char **newch, size_t* n)
654 {
655 	int fdp[3][2];
656 	int status, rv;
657 	size_t i;
658 	ssize_t r;
659 
660 #ifdef BUILTIN_DECOMPRESS
661         /* FIXME: This doesn't cope with bzip2 */
662 	if (method == 2)
663 		return uncompressgzipped(old, newch, bytes_max, n);
664 	if (compr[method].maglen == 0)
665 		return uncompresszlib(old, newch, bytes_max, n, 1);
666 #endif
667 	(void)fflush(stdout);
668 	(void)fflush(stderr);
669 
670 	for (i = 0; i < __arraycount(fdp); i++)
671 		fdp[i][0] = fdp[i][1] = -1;
672 
673 	if ((fd == -1 && pipe(fdp[STDIN_FILENO]) == -1) ||
674 	    pipe(fdp[STDOUT_FILENO]) == -1 || pipe(fdp[STDERR_FILENO]) == -1) {
675 		closep(fdp[STDIN_FILENO]);
676 		closep(fdp[STDOUT_FILENO]);
677 		return makeerror(newch, n, "Cannot create pipe, %s",
678 		    strerror(errno));
679 	}
680 	switch (fork()) {
681 	case 0:	/* child */
682 		if (fd != -1) {
683 			fdp[STDIN_FILENO][0] = fd;
684 			(void) lseek(fd, (off_t)0, SEEK_SET);
685 		}
686 
687 		for (i = 0; i < __arraycount(fdp); i++)
688 			copydesc(i, fdp[i]);
689 
690 		(void)execvp(compr[method].argv[0],
691 		    (char *const *)(intptr_t)compr[method].argv);
692 		dprintf(STDERR_FILENO, "exec `%s' failed, %s",
693 		    compr[method].argv[0], strerror(errno));
694 		exit(1);
695 		/*NOTREACHED*/
696 	case -1:
697 		return makeerror(newch, n, "Cannot fork, %s",
698 		    strerror(errno));
699 
700 	default: /* parent */
701 		for (i = 1; i < __arraycount(fdp); i++)
702 			closefd(fdp[i], 1);
703 
704 		/* Write the buffer data to the child, if we don't have fd */
705 		if (fd == -1)
706 			writechild(fdp, old, *n);
707 
708 		*newch = CAST(unsigned char *, malloc(bytes_max + 1));
709 		if (*newch == NULL) {
710 			rv = makeerror(newch, n, "No buffer, %s",
711 			    strerror(errno));
712 			goto err;
713 		}
714 		rv = OKDATA;
715 		if ((r = sread(fdp[STDOUT_FILENO][0], *newch, bytes_max, 0)) > 0)
716 			break;
717 		DPRINTF("Read stdout failed %d (%s)\n", fdp[STDOUT_FILENO][0],
718 		    r != -1 ? strerror(errno) : "no data");
719 
720 		rv = ERRDATA;
721 		if (r == 0 &&
722 		    (r = sread(fdp[STDERR_FILENO][0], *newch, bytes_max, 0)) > 0)
723 		{
724 			r = filter_error(*newch, r);
725 			break;
726 		}
727 		free(*newch);
728 		if  (r == 0)
729 			rv = makeerror(newch, n, "Read failed, %s",
730 			    strerror(errno));
731 		else
732 			rv = makeerror(newch, n, "No data");
733 		goto err;
734 	}
735 
736 	*n = r;
737 	/* NUL terminate, as every buffer is handled here. */
738 	(*newch)[*n] = '\0';
739 err:
740 	closefd(fdp[STDIN_FILENO], 1);
741 	closefd(fdp[STDOUT_FILENO], 0);
742 	closefd(fdp[STDERR_FILENO], 0);
743 	if (wait(&status) == -1) {
744 		free(*newch);
745 		rv = makeerror(newch, n, "Wait failed, %s", strerror(errno));
746 		DPRINTF("Child wait return %#x\n", status);
747 	} else if (!WIFEXITED(status)) {
748 		DPRINTF("Child not exited (0x%x)\n", status);
749 	} else if (WEXITSTATUS(status) != 0) {
750 		DPRINTF("Child exited (0x%d)\n", WEXITSTATUS(status));
751 	}
752 
753 	closefd(fdp[STDIN_FILENO], 0);
754 	DPRINTF("Returning %p n=%zu rv=%d\n", *newch, *n, rv);
755 
756 	return rv;
757 }
758 #endif
759