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
38FILE_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
62private 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
87private ssize_t swrite(int, const void *, size_t);
88#if HAVE_FORK
89private size_t ncompr = sizeof(compr) / sizeof(compr[0]);
90private size_t uncompressbuf(struct magic_set *, int, size_t,
91    const unsigned char *, unsigned char **, size_t);
92#ifdef BUILTIN_DECOMPRESS
93private size_t uncompressgzipped(struct magic_set *, const unsigned char *,
94    unsigned char **, size_t);
95#endif
96
97protected int
98file_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	}
136error:
137	free(newbuf);
138	ms->flags |= MAGIC_COMPRESS;
139	return rv;
140}
141#endif
142/*
143 * `safe' write for sockets and pipes.
144 */
145private ssize_t
146swrite(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 */
170protected ssize_t
171sread(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
219nocheck:
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
237protected int
238file_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
312private size_t
313uncompressgzipped(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
378private size_t
379uncompressbuf(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';
490err:
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
506