contrib/file/src/compress.c

/*
 * Copyright (c) Ian F. Darwin 1986-1995.
 * Software written by Ian F. Darwin and others;
 * maintained 1995-present by Christos Zoulas and others.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice immediately at the beginning of the file, without modification,
 *    this list of conditions, and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * compress routines:
 *	zmagic() - returns 0 if not recognized, uncompresses and prints
 *		   information if recognized
 *	uncompress(method, old, n, newch) - uncompress old into new,
 *					    using method, return sizeof new
 */
#include "file.h"

#ifndef lint
FILE_RCSID("@(#)$File: compress.c,v 1.68 2011/12/08 12:38:24 rrt Exp $")
#endif

#include "magic.h"
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <string.h>
#include <errno.h>
#ifndef __MINGW32__
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#if defined(HAVE_SYS_TIME_H)
#include <sys/time.h>
#endif
#if defined(HAVE_ZLIB_H) && defined(HAVE_LIBZ)
#define BUILTIN_DECOMPRESS
#include <zlib.h>
#endif

private const struct {
	const char magic[8];
	size_t maglen;
	const char *argv[3];
	int silent;
} compr[] = {
	{ "\037\235", 2, { "gzip", "-cdq", NULL }, 1 },		/* compressed */
	/* Uncompress can get stuck; so use gzip first if we have it
	 * Idea from Damien Clark, thanks! */
	{ "\037\235", 2, { "uncompress", "-c", NULL }, 1 },	/* compressed */
	{ "\037\213", 2, { "gzip", "-cdq", NULL }, 1 },		/* gzipped */
	{ "\037\236", 2, { "gzip", "-cdq", NULL }, 1 },		/* frozen */
	{ "\037\240", 2, { "gzip", "-cdq", NULL }, 1 },		/* SCO LZH */
	/* the standard pack utilities do not accept standard input */
	{ "\037\036", 2, { "gzip", "-cdq", NULL }, 0 },		/* packed */
	{ "PK\3\4",   4, { "gzip", "-cdq", NULL }, 1 },		/* pkzipped, */
					    /* ...only first file examined */
	{ "BZh",      3, { "bzip2", "-cd", NULL }, 1 },		/* bzip2-ed */
	{ "LZIP",     4, { "lzip", "-cdq", NULL }, 1 },
 	{ "\3757zXZ\0",6,{ "xz", "-cd", NULL }, 1 },		/* XZ Utils */
 	{ "LRZI",     4, { "lrzip", "-dqo-", NULL }, 1 },	/* LRZIP */
};

#define NODATA ((size_t)~0)

private ssize_t swrite(int, const void *, size_t);
#if HAVE_FORK
private size_t ncompr = sizeof(compr) / sizeof(compr[0]);
private size_t uncompressbuf(struct magic_set *, int, size_t,
    const unsigned char *, unsigned char **, size_t);
#ifdef BUILTIN_DECOMPRESS
private size_t uncompressgzipped(struct magic_set *, const unsigned char *,
    unsigned char **, size_t);
#endif

protected int
file_zmagic(struct magic_set *ms, int fd, const char *name,
    const unsigned char *buf, size_t nbytes)
{
	unsigned char *newbuf = NULL;
	size_t i, nsz;
	int rv = 0;
	int mime = ms->flags & MAGIC_MIME;

	if ((ms->flags & MAGIC_COMPRESS) == 0)
		return 0;

	for (i = 0; i < ncompr; i++) {
		if (nbytes < compr[i].maglen)
			continue;
		if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 &&
		    (nsz = uncompressbuf(ms, fd, i, buf, &newbuf,
		    nbytes)) != NODATA) {
			ms->flags &= ~MAGIC_COMPRESS;
			rv = -1;
			if (file_buffer(ms, -1, name, newbuf, nsz) == -1)
				goto error;

			if (mime == MAGIC_MIME || mime == 0) {
				if (file_printf(ms, mime ?
				    " compressed-encoding=" : " (") == -1)
					goto error;
			}

			if ((mime == 0 || mime & MAGIC_MIME_ENCODING) &&
			    file_buffer(ms, -1, NULL, buf, nbytes) == -1)
				goto error;

			if (!mime && file_printf(ms, ")") == -1)
				goto error;
			rv = 1;
			break;
		}
	}
error:
	free(newbuf);
	ms->flags |= MAGIC_COMPRESS;
	return rv;
}
#endif
/*
 * `safe' write for sockets and pipes.
 */
private ssize_t
swrite(int fd, const void *buf, size_t n)
{
	ssize_t rv;
	size_t rn = n;

	do
		switch (rv = write(fd, buf, n)) {
		case -1:
			if (errno == EINTR)
				continue;
			return -1;
		default:
			n -= rv;
			buf = CAST(const char *, buf) + rv;
			break;
		}
	while (n > 0);
	return rn;
}


/*
 * `safe' read for sockets and pipes.
 */
protected ssize_t
sread(int fd, void *buf, size_t n, int canbepipe __attribute__ ((unused)))
{
	ssize_t rv;
#ifdef FD_ZERO
	ssize_t cnt;
#endif
#ifdef FIONREAD
	int t = 0;
#endif
	size_t rn = n;

	if (fd == STDIN_FILENO)
		goto nocheck;

#ifdef FIONREAD
	if ((canbepipe && (ioctl(fd, FIONREAD, &t) == -1)) || (t == 0)) {
#ifdef FD_ZERO
		for (cnt = 0;; cnt++) {
			fd_set check;
			struct timeval tout = {0, 100 * 1000};
			int selrv;

			FD_ZERO(&check);
			FD_SET(fd, &check);

			/*
			 * Avoid soft deadlock: do not read if there
			 * is nothing to read from sockets and pipes.
			 */
			selrv = select(fd + 1, &check, NULL, NULL, &tout);
			if (selrv == -1) {
				if (errno == EINTR || errno == EAGAIN)
					continue;
			} else if (selrv == 0 && cnt >= 5) {
				return 0;
			} else
				break;
		}
#endif
		(void)ioctl(fd, FIONREAD, &t);
	}

	if (t > 0 && (size_t)t < n) {
		n = t;
		rn = n;
	}
#endif

nocheck:
	do
		switch ((rv = read(fd, buf, n))) {
		case -1:
			if (errno == EINTR)
				continue;
			return -1;
		case 0:
			return rn - n;
		default:
			n -= rv;
			buf = ((char *)buf) + rv;
			break;
		}
	while (n > 0);
	return rn;
}

protected int
file_pipe2file(struct magic_set *ms, int fd, const void *startbuf,
    size_t nbytes)
{
	char buf[4096];
	ssize_t r;
	int tfd;
#ifdef HAVE_MKSTEMP
	int te;
#endif

	(void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf);
#ifndef HAVE_MKSTEMP
	{
		char *ptr = mktemp(buf);
		tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600);
		r = errno;
		(void)unlink(ptr);
		errno = r;
	}
#else
	tfd = mkstemp(buf);
	te = errno;
	(void)unlink(buf);
	errno = te;
#endif
	if (tfd == -1) {
		file_error(ms, errno,
		    "cannot create temporary file for pipe copy");
		return -1;
	}

	if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes)
		r = 1;
	else {
		while ((r = sread(fd, buf, sizeof(buf), 1)) > 0)
			if (swrite(tfd, buf, (size_t)r) != r)
				break;
	}

	switch (r) {
	case -1:
		file_error(ms, errno, "error copying from pipe to temp file");
		return -1;
	case 0:
		break;
	default:
		file_error(ms, errno, "error while writing to temp file");
		return -1;
	}

	/*
	 * We duplicate the file descriptor, because fclose on a
	 * tmpfile will delete the file, but any open descriptors
	 * can still access the phantom inode.
	 */
	if ((fd = dup2(tfd, fd)) == -1) {
		file_error(ms, errno, "could not dup descriptor for temp file");
		return -1;
	}
	(void)close(tfd);
	if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
		file_badseek(ms);
		return -1;
	}
	return fd;
}
#if HAVE_FORK
#ifdef BUILTIN_DECOMPRESS

#define FHCRC		(1 << 1)
#define FEXTRA		(1 << 2)
#define FNAME		(1 << 3)
#define FCOMMENT	(1 << 4)

private size_t
uncompressgzipped(struct magic_set *ms, const unsigned char *old,
    unsigned char **newch, size_t n)
{
	unsigned char flg = old[3];
	size_t data_start = 10;
	z_stream z;
	int rc;

	if (flg & FEXTRA) {
		if (data_start+1 >= n)
			return 0;
		data_start += 2 + old[data_start] + old[data_start + 1] * 256;
	}
	if (flg & FNAME) {
		while(data_start < n && old[data_start])
			data_start++;
		data_start++;
	}
	if(flg & FCOMMENT) {
		while(data_start < n && old[data_start])
			data_start++;
		data_start++;
	}
	if(flg & FHCRC)
		data_start += 2;

	if (data_start >= n)
		return 0;
	if ((*newch = CAST(unsigned char *, malloc(HOWMANY + 1))) == NULL) {
		return 0;
	}

	/* XXX: const castaway, via strchr */
	z.next_in = (Bytef *)strchr((const char *)old + data_start,
	    old[data_start]);
	z.avail_in = CAST(uint32_t, (n - data_start));
	z.next_out = *newch;
	z.avail_out = HOWMANY;
	z.zalloc = Z_NULL;
	z.zfree = Z_NULL;
	z.opaque = Z_NULL;

	/* LINTED bug in header macro */
	rc = inflateInit2(&z, -15);
	if (rc != Z_OK) {
		file_error(ms, 0, "zlib: %s", z.msg);
		return 0;
	}

	rc = inflate(&z, Z_SYNC_FLUSH);
	if (rc != Z_OK && rc != Z_STREAM_END) {
		file_error(ms, 0, "zlib: %s", z.msg);
		return 0;
	}

	n = (size_t)z.total_out;
	(void)inflateEnd(&z);

	/* let's keep the nul-terminate tradition */
	(*newch)[n] = '\0';

	return n;
}
#endif

private size_t
uncompressbuf(struct magic_set *ms, int fd, size_t method,
    const unsigned char *old, unsigned char **newch, size_t n)
{
	int fdin[2], fdout[2];
	ssize_t r;
	pid_t pid;

#ifdef BUILTIN_DECOMPRESS
        /* FIXME: This doesn't cope with bzip2 */
	if (method == 2)
		return uncompressgzipped(ms, old, newch, n);
#endif
	(void)fflush(stdout);
	(void)fflush(stderr);

	if ((fd != -1 && pipe(fdin) == -1) || pipe(fdout) == -1) {
		file_error(ms, errno, "cannot create pipe");
		return NODATA;
	}
	switch (pid = fork()) {
	case 0:	/* child */
		(void) close(0);
		if (fd != -1) {
		    (void) dup(fd);
		    (void) lseek(0, (off_t)0, SEEK_SET);
		} else {
		    (void) dup(fdin[0]);
		    (void) close(fdin[0]);
		    (void) close(fdin[1]);
		}

		(void) close(1);
		(void) dup(fdout[1]);
		(void) close(fdout[0]);
		(void) close(fdout[1]);
#ifndef DEBUG
		if (compr[method].silent)
			(void)close(2);
#endif

		(void)execvp(compr[method].argv[0],
		    (char *const *)(intptr_t)compr[method].argv);
#ifdef DEBUG
		(void)fprintf(stderr, "exec `%s' failed (%s)\n",
		    compr[method].argv[0], strerror(errno));
#endif
		exit(1);
		/*NOTREACHED*/
	case -1:
		file_error(ms, errno, "could not fork");
		return NODATA;

	default: /* parent */
		(void) close(fdout[1]);
		if (fd == -1) {
			(void) close(fdin[0]);
			/*
			 * fork again, to avoid blocking because both
			 * pipes filled
			 */
			switch (fork()) {
			case 0: /* child */
				(void)close(fdout[0]);
				if (swrite(fdin[1], old, n) != (ssize_t)n) {
#ifdef DEBUG
					(void)fprintf(stderr,
					    "Write failed (%s)\n",
					    strerror(errno));
#endif
					exit(1);
				}
				exit(0);
				/*NOTREACHED*/

			case -1:
#ifdef DEBUG
				(void)fprintf(stderr, "Fork failed (%s)\n",
				    strerror(errno));
#endif
				exit(1);
				/*NOTREACHED*/

			default:  /* parent */
				break;
			}
			(void) close(fdin[1]);
			fdin[1] = -1;
		}

		if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) {
#ifdef DEBUG
			(void)fprintf(stderr, "Malloc failed (%s)\n",
			    strerror(errno));
#endif
			n = 0;
			goto err;
		}
		if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) {
#ifdef DEBUG
			(void)fprintf(stderr, "Read failed (%s)\n",
			    strerror(errno));
#endif
			free(*newch);
			n = 0;
			newch[0] = '\0';
			goto err;
		} else {
			n = r;
		}
 		/* NUL terminate, as every buffer is handled here. */
 		(*newch)[n] = '\0';
err:
		if (fdin[1] != -1)
			(void) close(fdin[1]);
		(void) close(fdout[0]);
#ifdef WNOHANG
		while (waitpid(pid, NULL, WNOHANG) != -1)
			continue;
#else
		(void)wait(NULL);
#endif
		(void) close(fdin[0]);

		return n;
	}
}
#endif
Commit	Line	Data
	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 1.68 2011/12/08 12:38:24 rrt 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	free(newbuf);
	138	ms->flags \|= MAGIC_COMPRESS;
	139	return rv;
	140	}
	141	#endif
	142	/*
	143	* `safe' write for sockets and pipes.
	144	*/
	145	private ssize_t
	146	swrite(int fd, const void *buf, size_t n)
	147	{
	148	ssize_t rv;
	149	size_t rn = n;
	150
	151	do
	152	switch (rv = write(fd, buf, n)) {
	153	case -1:
	154	if (errno == EINTR)
	155	continue;
	156	return -1;
	157	default:
	158	n -= rv;
	159	buf = CAST(const char *, buf) + rv;
	160	break;
	161	}
	162	while (n > 0);
	163	return rn;
	164	}
	165
	166
	167	/*
	168	* `safe' read for sockets and pipes.
	169	*/
	170	protected ssize_t
	171	sread(int fd, void *buf, size_t n, int canbepipe __attribute__ ((unused)))
	172	{
	173	ssize_t rv;
	174	#ifdef FD_ZERO
	175	ssize_t cnt;
	176	#endif
	177	#ifdef FIONREAD
	178	int t = 0;
	179	#endif
	180	size_t rn = n;
	181
	182	if (fd == STDIN_FILENO)
	183	goto nocheck;
	184
	185	#ifdef FIONREAD
	186	if ((canbepipe && (ioctl(fd, FIONREAD, &t) == -1)) \|\| (t == 0)) {
	187	#ifdef FD_ZERO
	188	for (cnt = 0;; cnt++) {
	189	fd_set check;
	190	struct timeval tout = {0, 100 * 1000};
	191	int selrv;
	192
	193	FD_ZERO(&check);
	194	FD_SET(fd, &check);
	195
	196	/*
	197	* Avoid soft deadlock: do not read if there
	198	* is nothing to read from sockets and pipes.
	199	*/
	200	selrv = select(fd + 1, &check, NULL, NULL, &tout);
	201	if (selrv == -1) {
	202	if (errno == EINTR \|\| errno == EAGAIN)
	203	continue;
	204	} else if (selrv == 0 && cnt >= 5) {
	205	return 0;
	206	} else
	207	break;
	208	}
	209	#endif
	210	(void)ioctl(fd, FIONREAD, &t);
	211	}
	212
	213	if (t > 0 && (size_t)t < n) {
	214	n = t;
	215	rn = n;
	216	}
	217	#endif
	218
	219	nocheck:
	220	do
	221	switch ((rv = read(fd, buf, n))) {
	222	case -1:
	223	if (errno == EINTR)
	224	continue;
	225	return -1;
	226	case 0:
	227	return rn - n;
	228	default:
	229	n -= rv;
	230	buf = ((char *)buf) + rv;
	231	break;
	232	}
	233	while (n > 0);
	234	return rn;
	235	}
	236
	237	protected int
	238	file_pipe2file(struct magic_set ms, int fd, const void startbuf,
	239	size_t nbytes)
	240	{
	241	char buf[4096];
	242	ssize_t r;
	243	int tfd;
	244	#ifdef HAVE_MKSTEMP
	245	int te;
	246	#endif
	247
	248	(void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf);
	249	#ifndef HAVE_MKSTEMP
	250	{
	251	char *ptr = mktemp(buf);
	252	tfd = open(ptr, O_RDWR\|O_TRUNC\|O_EXCL\|O_CREAT, 0600);
	253	r = errno;
	254	(void)unlink(ptr);
	255	errno = r;
	256	}
	257	#else
	258	tfd = mkstemp(buf);
	259	te = errno;
	260	(void)unlink(buf);
	261	errno = te;
	262	#endif
	263	if (tfd == -1) {
	264	file_error(ms, errno,
	265	"cannot create temporary file for pipe copy");
	266	return -1;
	267	}
	268
	269	if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes)
	270	r = 1;
	271	else {
	272	while ((r = sread(fd, buf, sizeof(buf), 1)) > 0)
	273	if (swrite(tfd, buf, (size_t)r) != r)
	274	break;
	275	}
	276
	277	switch (r) {
	278	case -1:
	279	file_error(ms, errno, "error copying from pipe to temp file");
	280	return -1;
	281	case 0:
	282	break;
	283	default:
	284	file_error(ms, errno, "error while writing to temp file");
	285	return -1;
	286	}
	287
	288	/*
	289	* We duplicate the file descriptor, because fclose on a
	290	* tmpfile will delete the file, but any open descriptors
	291	* can still access the phantom inode.
	292	*/
	293	if ((fd = dup2(tfd, fd)) == -1) {
	294	file_error(ms, errno, "could not dup descriptor for temp file");
	295	return -1;
	296	}
	297	(void)close(tfd);
	298	if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
	299	file_badseek(ms);
	300	return -1;
	301	}
	302	return fd;
	303	}
	304	#if HAVE_FORK
	305	#ifdef BUILTIN_DECOMPRESS
	306
	307	#define FHCRC (1 << 1)
	308	#define FEXTRA (1 << 2)
	309	#define FNAME (1 << 3)
	310	#define FCOMMENT (1 << 4)
	311
	312	private size_t
	313	uncompressgzipped(struct magic_set ms, const unsigned char old,
	314	unsigned char **newch, size_t n)
	315	{
	316	unsigned char flg = old[3];
	317	size_t data_start = 10;
	318	z_stream z;
	319	int rc;
	320
	321	if (flg & FEXTRA) {
	322	if (data_start+1 >= n)
	323	return 0;
	324	data_start += 2 + old[data_start] + old[data_start + 1] * 256;
	325	}
	326	if (flg & FNAME) {
	327	while(data_start < n && old[data_start])
	328	data_start++;
	329	data_start++;
	330	}
	331	if(flg & FCOMMENT) {
	332	while(data_start < n && old[data_start])
	333	data_start++;
	334	data_start++;
	335	}
	336	if(flg & FHCRC)
	337	data_start += 2;
	338
	339	if (data_start >= n)
	340	return 0;
	341	if ((newch = CAST(unsigned char , malloc(HOWMANY + 1))) == NULL) {
	342	return 0;
	343	}
	344
	345	/* XXX: const castaway, via strchr */
	346	z.next_in = (Bytef )strchr((const char )old + data_start,
	347	old[data_start]);
	348	z.avail_in = CAST(uint32_t, (n - data_start));
	349	z.next_out = *newch;
	350	z.avail_out = HOWMANY;
	351	z.zalloc = Z_NULL;
	352	z.zfree = Z_NULL;
	353	z.opaque = Z_NULL;
	354
	355	/* LINTED bug in header macro */
	356	rc = inflateInit2(&z, -15);
	357	if (rc != Z_OK) {
	358	file_error(ms, 0, "zlib: %s", z.msg);
	359	return 0;
	360	}
	361
	362	rc = inflate(&z, Z_SYNC_FLUSH);
	363	if (rc != Z_OK && rc != Z_STREAM_END) {
	364	file_error(ms, 0, "zlib: %s", z.msg);
	365	return 0;
	366	}
	367
	368	n = (size_t)z.total_out;
	369	(void)inflateEnd(&z);
	370
	371	/* let's keep the nul-terminate tradition */
	372	(*newch)[n] = '\0';
	373
	374	return n;
	375	}
	376	#endif
	377
	378	private size_t
	379	uncompressbuf(struct magic_set *ms, int fd, size_t method,
	380	const unsigned char old, unsigned char *newch, size_t n)
	381	{
	382	int fdin[2], fdout[2];
	383	ssize_t r;
	384	pid_t pid;
	385
	386	#ifdef BUILTIN_DECOMPRESS
	387	/* FIXME: This doesn't cope with bzip2 */
	388	if (method == 2)
	389	return uncompressgzipped(ms, old, newch, n);
	390	#endif
	391	(void)fflush(stdout);
	392	(void)fflush(stderr);
	393
	394	if ((fd != -1 && pipe(fdin) == -1) \|\| pipe(fdout) == -1) {
	395	file_error(ms, errno, "cannot create pipe");
	396	return NODATA;
	397	}
	398	switch (pid = fork()) {
	399	case 0: /* child */
	400	(void) close(0);
	401	if (fd != -1) {
	402	(void) dup(fd);
	403	(void) lseek(0, (off_t)0, SEEK_SET);
	404	} else {
	405	(void) dup(fdin[0]);
	406	(void) close(fdin[0]);
	407	(void) close(fdin[1]);
	408	}
	409
	410	(void) close(1);
	411	(void) dup(fdout[1]);
	412	(void) close(fdout[0]);
	413	(void) close(fdout[1]);
	414	#ifndef DEBUG
	415	if (compr[method].silent)
	416	(void)close(2);
	417	#endif
	418
	419	(void)execvp(compr[method].argv[0],
	420	(char const )(intptr_t)compr[method].argv);
	421	#ifdef DEBUG
	422	(void)fprintf(stderr, "exec `%s' failed (%s)\n",
	423	compr[method].argv[0], strerror(errno));
	424	#endif
	425	exit(1);
	426	/NOTREACHED/
	427	case -1:
	428	file_error(ms, errno, "could not fork");
	429	return NODATA;
	430
	431	default: /* parent */
	432	(void) close(fdout[1]);
	433	if (fd == -1) {
	434	(void) close(fdin[0]);
	435	/*
	436	* fork again, to avoid blocking because both
	437	* pipes filled
	438	*/
	439	switch (fork()) {
	440	case 0: /* child */
	441	(void)close(fdout[0]);
	442	if (swrite(fdin[1], old, n) != (ssize_t)n) {
	443	#ifdef DEBUG
	444	(void)fprintf(stderr,
	445	"Write failed (%s)\n",
	446	strerror(errno));
	447	#endif
	448	exit(1);
	449	}
	450	exit(0);
	451	/NOTREACHED/
	452
	453	case -1:
	454	#ifdef DEBUG
	455	(void)fprintf(stderr, "Fork failed (%s)\n",
	456	strerror(errno));
	457	#endif
	458	exit(1);
	459	/NOTREACHED/
	460
	461	default: /* parent */
	462	break;
	463	}
	464	(void) close(fdin[1]);
	465	fdin[1] = -1;
	466	}
	467
	468	if ((newch = (unsigned char ) malloc(HOWMANY + 1)) == NULL) {
	469	#ifdef DEBUG
	470	(void)fprintf(stderr, "Malloc failed (%s)\n",
	471	strerror(errno));
	472	#endif
	473	n = 0;
	474	goto err;
	475	}
	476	if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) {
	477	#ifdef DEBUG
	478	(void)fprintf(stderr, "Read failed (%s)\n",
	479	strerror(errno));
	480	#endif
	481	free(*newch);
	482	n = 0;
	483	newch[0] = '\0';
	484	goto err;
	485	} else {
	486	n = r;
	487	}
	488	/* NUL terminate, as every buffer is handled here. */
	489	(*newch)[n] = '\0';
	490	err:
	491	if (fdin[1] != -1)
	492	(void) close(fdin[1]);
	493	(void) close(fdout[0]);
	494	#ifdef WNOHANG
	495	while (waitpid(pid, NULL, WNOHANG) != -1)
	496	continue;
	497	#else
	498	(void)wait(NULL);
	499	#endif
	500	(void) close(fdin[0]);
	501
	502	return n;
	503	}
	504	}
	505	#endif