funcs.c revision 191736 
1/*
2 * Copyright (c) Christos Zoulas 2003.
3 * All Rights Reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice immediately at the beginning of the file, without modification,
10 *    this list of conditions, and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
19 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27#include "file.h"
28
29#ifndef	lint
30FILE_RCSID("@(#)$File: funcs.c,v 1.51 2008/11/07 18:57:28 christos Exp $")
31#endif	/* lint */
32
33#include "magic.h"
34#include <stdarg.h>
35#include <stdlib.h>
36#include <string.h>
37#include <ctype.h>
38#if defined(HAVE_WCHAR_H)
39#include <wchar.h>
40#endif
41#if defined(HAVE_WCTYPE_H)
42#include <wctype.h>
43#endif
44#if defined(HAVE_LIMITS_H)
45#include <limits.h>
46#endif
47
48#ifndef SIZE_MAX
49#define SIZE_MAX	((size_t)~0)
50#endif
51
52/*
53 * Like printf, only we append to a buffer.
54 */
55protected int
56file_vprintf(struct magic_set *ms, const char *fmt, va_list ap)
57{
58	int len;
59	char *buf, *newstr;
60
61	len = vasprintf(&buf, fmt, ap);
62	if (len < 0)
63		goto out;
64
65	if (ms->o.buf != NULL) {
66		len = asprintf(&newstr, "%s%s", ms->o.buf, buf);
67		free(buf);
68		if (len < 0)
69			goto out;
70		free(ms->o.buf);
71		buf = newstr;
72	}
73	ms->o.buf = buf;
74	return 0;
75out:
76	file_error(ms, errno, "vasprintf failed");
77	return -1;
78}
79
80protected int
81file_printf(struct magic_set *ms, const char *fmt, ...)
82{
83	int rv;
84	va_list ap;
85
86	va_start(ap, fmt);
87	rv = file_vprintf(ms, fmt, ap);
88	va_end(ap);
89	return rv;
90}
91
92/*
93 * error - print best error message possible
94 */
95/*VARARGS*/
96private void
97file_error_core(struct magic_set *ms, int error, const char *f, va_list va,
98    uint32_t lineno)
99{
100	/* Only the first error is ok */
101	if (ms->event_flags & EVENT_HAD_ERR)
102		return;
103	if (lineno != 0) {
104		free(ms->o.buf);
105		ms->o.buf = NULL;
106		file_printf(ms, "line %u: ", lineno);
107	}
108	file_vprintf(ms, f, va);
109	if (error > 0)
110		file_printf(ms, " (%s)", strerror(error));
111	ms->event_flags |= EVENT_HAD_ERR;
112	ms->error = error;
113}
114
115/*VARARGS*/
116protected void
117file_error(struct magic_set *ms, int error, const char *f, ...)
118{
119	va_list va;
120	va_start(va, f);
121	file_error_core(ms, error, f, va, 0);
122	va_end(va);
123}
124
125/*
126 * Print an error with magic line number.
127 */
128/*VARARGS*/
129protected void
130file_magerror(struct magic_set *ms, const char *f, ...)
131{
132	va_list va;
133	va_start(va, f);
134	file_error_core(ms, 0, f, va, ms->line);
135	va_end(va);
136}
137
138protected void
139file_oomem(struct magic_set *ms, size_t len)
140{
141	file_error(ms, errno, "cannot allocate %zu bytes", len);
142}
143
144protected void
145file_badseek(struct magic_set *ms)
146{
147	file_error(ms, errno, "error seeking");
148}
149
150protected void
151file_badread(struct magic_set *ms)
152{
153	file_error(ms, errno, "error reading");
154}
155
156#ifndef COMPILE_ONLY
157protected int
158file_buffer(struct magic_set *ms, int fd, const char *inname, const void *buf,
159    size_t nb)
160{
161	int m = 0, rv = 0, looks_text = 0;
162	int mime = ms->flags & MAGIC_MIME;
163	const unsigned char *ubuf = CAST(const unsigned char *, buf);
164	unichar *u8buf = NULL;
165	size_t ulen;
166	const char *code = NULL;
167	const char *code_mime = "binary";
168	const char *type = NULL;
169
170
171
172	if (nb == 0) {
173		if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
174		    file_printf(ms, mime ? "application/x-empty" :
175		    "empty") == -1)
176			return -1;
177		return 1;
178	} else if (nb == 1) {
179		if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
180		    file_printf(ms, mime ? "application/octet-stream" :
181		    "very short file (no magic)") == -1)
182			return -1;
183		return 1;
184	}
185
186	if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
187		looks_text = file_encoding(ms, ubuf, nb, &u8buf, &ulen,
188		    &code, &code_mime, &type);
189	}
190
191#ifdef __EMX__
192	if ((ms->flags & MAGIC_NO_CHECK_APPTYPE) == 0 && inname) {
193		switch (file_os2_apptype(ms, inname, buf, nb)) {
194		case -1:
195			return -1;
196		case 0:
197			break;
198		default:
199			return 1;
200		}
201	}
202#endif
203
204	/* try compression stuff */
205	if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) == 0)
206		if ((m = file_zmagic(ms, fd, inname, ubuf, nb)) != 0) {
207			if ((ms->flags & MAGIC_DEBUG) != 0)
208				(void)fprintf(stderr, "zmagic %d\n", m);
209			goto done;
210		}
211
212	/* Check if we have a tar file */
213	if ((ms->flags & MAGIC_NO_CHECK_TAR) == 0)
214		if ((m = file_is_tar(ms, ubuf, nb)) != 0) {
215			if ((ms->flags & MAGIC_DEBUG) != 0)
216				(void)fprintf(stderr, "tar %d\n", m);
217			goto done;
218		}
219
220	/* Check if we have a CDF file */
221	if ((ms->flags & MAGIC_NO_CHECK_CDF) == 0)
222		if ((m = file_trycdf(ms, fd, ubuf, nb)) != 0) {
223			if ((ms->flags & MAGIC_DEBUG) != 0)
224				(void)fprintf(stderr, "cdf %d\n", m);
225			goto done;
226		}
227
228	/* try soft magic tests */
229	if ((ms->flags & MAGIC_NO_CHECK_SOFT) == 0)
230		if ((m = file_softmagic(ms, ubuf, nb, BINTEST)) != 0) {
231			if ((ms->flags & MAGIC_DEBUG) != 0)
232				(void)fprintf(stderr, "softmagic %d\n", m);
233#ifdef BUILTIN_ELF
234			if ((ms->flags & MAGIC_NO_CHECK_ELF) == 0 && m == 1 &&
235			    nb > 5 && fd != -1) {
236				/*
237				 * We matched something in the file, so this
238				 * *might* be an ELF file, and the file is at
239				 * least 5 bytes long, so if it's an ELF file
240				 * it has at least one byte past the ELF magic
241				 * number - try extracting information from the
242				 * ELF headers that cannot easily * be
243				 * extracted with rules in the magic file.
244				 */
245				if ((m = file_tryelf(ms, fd, ubuf, nb)) != 0)
246					if ((ms->flags & MAGIC_DEBUG) != 0)
247						(void)fprintf(stderr,
248						    "elf %d\n", m);
249			}
250#endif
251			goto done;
252		}
253
254	/* try text properties (and possibly text tokens) */
255	if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) {
256
257		if ((m = file_ascmagic(ms, ubuf, nb)) != 0) {
258			if ((ms->flags & MAGIC_DEBUG) != 0)
259				(void)fprintf(stderr, "ascmagic %d\n", m);
260			goto done;
261		}
262
263		/* try to discover text encoding */
264		if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
265			if (looks_text == 0)
266				if ((m = file_ascmagic_with_encoding( ms, ubuf,
267				    nb, u8buf, ulen, code, type)) != 0) {
268					if ((ms->flags & MAGIC_DEBUG) != 0)
269						(void)fprintf(stderr,
270						    "ascmagic/enc %d\n", m);
271					goto done;
272				}
273		}
274	}
275
276	/* give up */
277	m = 1;
278	if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
279	    file_printf(ms, mime ? "application/octet-stream" : "data") == -1) {
280	    rv = -1;
281	}
282 done:
283	if ((ms->flags & MAGIC_MIME_ENCODING) != 0) {
284		if (ms->flags & MAGIC_MIME_TYPE)
285			if (file_printf(ms, "; charset=") == -1)
286				rv = -1;
287		if (file_printf(ms, "%s", code_mime) == -1)
288			rv = -1;
289	}
290	if (u8buf)
291		free(u8buf);
292	if (rv)
293		return rv;
294
295	return m;
296}
297#endif
298
299protected int
300file_reset(struct magic_set *ms)
301{
302	if (ms->mlist == NULL) {
303		file_error(ms, 0, "no magic files loaded");
304		return -1;
305	}
306	ms->o.buf = NULL;
307	ms->event_flags &= ~EVENT_HAD_ERR;
308	ms->error = -1;
309	return 0;
310}
311
312#define OCTALIFY(n, o)	\
313	/*LINTED*/ \
314	(void)(*(n)++ = '\\', \
315	*(n)++ = (((uint32_t)*(o) >> 6) & 3) + '0', \
316	*(n)++ = (((uint32_t)*(o) >> 3) & 7) + '0', \
317	*(n)++ = (((uint32_t)*(o) >> 0) & 7) + '0', \
318	(o)++)
319
320protected const char *
321file_getbuffer(struct magic_set *ms)
322{
323	char *pbuf, *op, *np;
324	size_t psize, len;
325
326	if (ms->event_flags & EVENT_HAD_ERR)
327		return NULL;
328
329	if (ms->flags & MAGIC_RAW)
330		return ms->o.buf;
331
332	if (ms->o.buf == NULL)
333		return NULL;
334
335	/* * 4 is for octal representation, + 1 is for NUL */
336	len = strlen(ms->o.buf);
337	if (len > (SIZE_MAX - 1) / 4) {
338		file_oomem(ms, len);
339		return NULL;
340	}
341	psize = len * 4 + 1;
342	if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) {
343		file_oomem(ms, psize);
344		return NULL;
345	}
346	ms->o.pbuf = pbuf;
347
348#if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
349	{
350		mbstate_t state;
351		wchar_t nextchar;
352		int mb_conv = 1;
353		size_t bytesconsumed;
354		char *eop;
355		(void)memset(&state, 0, sizeof(mbstate_t));
356
357		np = ms->o.pbuf;
358		op = ms->o.buf;
359		eop = op + len;
360
361		while (op < eop) {
362			bytesconsumed = mbrtowc(&nextchar, op,
363			    (size_t)(eop - op), &state);
364			if (bytesconsumed == (size_t)(-1) ||
365			    bytesconsumed == (size_t)(-2)) {
366				mb_conv = 0;
367				break;
368			}
369
370			if (iswprint(nextchar)) {
371				(void)memcpy(np, op, bytesconsumed);
372				op += bytesconsumed;
373				np += bytesconsumed;
374			} else {
375				while (bytesconsumed-- > 0)
376					OCTALIFY(np, op);
377			}
378		}
379		*np = '\0';
380
381		/* Parsing succeeded as a multi-byte sequence */
382		if (mb_conv != 0)
383			return ms->o.pbuf;
384	}
385#endif
386
387	for (np = ms->o.pbuf, op = ms->o.buf; *op; op++) {
388		if (isprint((unsigned char)*op)) {
389			*np++ = *op;
390		} else {
391			OCTALIFY(np, op);
392		}
393	}
394	*np = '\0';
395	return ms->o.pbuf;
396}
397
398protected int
399file_check_mem(struct magic_set *ms, unsigned int level)
400{
401	size_t len;
402
403	if (level >= ms->c.len) {
404		len = (ms->c.len += 20) * sizeof(*ms->c.li);
405		ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ?
406		    malloc(len) :
407		    realloc(ms->c.li, len));
408		if (ms->c.li == NULL) {
409			file_oomem(ms, len);
410			return -1;
411		}
412	}
413	ms->c.li[level].got_match = 0;
414#ifdef ENABLE_CONDITIONALS
415	ms->c.li[level].last_match = 0;
416	ms->c.li[level].last_cond = COND_NONE;
417#endif /* ENABLE_CONDITIONALS */
418	return 0;
419}
420