funcs.c revision 267829 
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 1.60 2011/12/08 12:38:24 rrt 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    size_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 %" SIZE_T_FORMAT "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 %" SIZE_T_FORMAT "u bytes",
142	    len);
143}
144
145protected void
146file_badseek(struct magic_set *ms)
147{
148	file_error(ms, errno, "error seeking");
149}
150
151protected void
152file_badread(struct magic_set *ms)
153{
154	file_error(ms, errno, "error reading");
155}
156
157#ifndef COMPILE_ONLY
158protected int
159file_buffer(struct magic_set *ms, int fd, const char *inname __attribute__ ((unused)),
160    const void *buf, size_t nb)
161{
162	int m = 0, rv = 0, looks_text = 0;
163	int mime = ms->flags & MAGIC_MIME;
164	const unsigned char *ubuf = CAST(const unsigned char *, buf);
165	unichar *u8buf = NULL;
166	size_t ulen;
167	const char *code = NULL;
168	const char *code_mime = "binary";
169	const char *type = NULL;
170
171
172
173	if (nb == 0) {
174		if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
175		    file_printf(ms, mime ? "application/x-empty" :
176		    "empty") == -1)
177			return -1;
178		return 1;
179	} else if (nb == 1) {
180		if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
181		    file_printf(ms, mime ? "application/octet-stream" :
182		    "very short file (no magic)") == -1)
183			return -1;
184		return 1;
185	}
186
187	if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
188		looks_text = file_encoding(ms, ubuf, nb, &u8buf, &ulen,
189		    &code, &code_mime, &type);
190	}
191
192#ifdef __EMX__
193	if ((ms->flags & MAGIC_NO_CHECK_APPTYPE) == 0 && inname) {
194		switch (file_os2_apptype(ms, inname, buf, nb)) {
195		case -1:
196			return -1;
197		case 0:
198			break;
199		default:
200			return 1;
201		}
202	}
203#endif
204#if HAVE_FORK
205	/* try compression stuff */
206	if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) == 0)
207		if ((m = file_zmagic(ms, fd, inname, ubuf, nb)) != 0) {
208			if ((ms->flags & MAGIC_DEBUG) != 0)
209				(void)fprintf(stderr, "zmagic %d\n", m);
210			goto done;
211		}
212#endif
213	/* Check if we have a tar file */
214	if ((ms->flags & MAGIC_NO_CHECK_TAR) == 0)
215		if ((m = file_is_tar(ms, ubuf, nb)) != 0) {
216			if ((ms->flags & MAGIC_DEBUG) != 0)
217				(void)fprintf(stderr, "tar %d\n", m);
218			goto done;
219		}
220
221	/* Check if we have a CDF file */
222	if ((ms->flags & MAGIC_NO_CHECK_CDF) == 0)
223		if ((m = file_trycdf(ms, fd, ubuf, nb)) != 0) {
224			if ((ms->flags & MAGIC_DEBUG) != 0)
225				(void)fprintf(stderr, "cdf %d\n", m);
226			goto done;
227		}
228
229	/* try soft magic tests */
230	if ((ms->flags & MAGIC_NO_CHECK_SOFT) == 0)
231		if ((m = file_softmagic(ms, ubuf, nb, 0, BINTEST,
232		    looks_text)) != 0) {
233			if ((ms->flags & MAGIC_DEBUG) != 0)
234				(void)fprintf(stderr, "softmagic %d\n", m);
235#ifdef BUILTIN_ELF
236			if ((ms->flags & MAGIC_NO_CHECK_ELF) == 0 && m == 1 &&
237			    nb > 5 && fd != -1) {
238				/*
239				 * We matched something in the file, so this
240				 * *might* be an ELF file, and the file is at
241				 * least 5 bytes long, so if it's an ELF file
242				 * it has at least one byte past the ELF magic
243				 * number - try extracting information from the
244				 * ELF headers that cannot easily * be
245				 * extracted with rules in the magic file.
246				 */
247				if ((m = file_tryelf(ms, fd, ubuf, nb)) != 0)
248					if ((ms->flags & MAGIC_DEBUG) != 0)
249						(void)fprintf(stderr,
250						    "elf %d\n", m);
251			}
252#endif
253			goto done;
254		}
255
256	/* try text properties */
257	if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) {
258
259		if ((m = file_ascmagic(ms, ubuf, nb, looks_text)) != 0) {
260			if ((ms->flags & MAGIC_DEBUG) != 0)
261				(void)fprintf(stderr, "ascmagic %d\n", m);
262			goto done;
263		}
264
265		/* try to discover text encoding */
266		if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
267			if (looks_text == 0)
268				if ((m = file_ascmagic_with_encoding( ms, ubuf,
269				    nb, u8buf, ulen, code, type, looks_text))
270				    != 0) {
271					if ((ms->flags & MAGIC_DEBUG) != 0)
272						(void)fprintf(stderr,
273						    "ascmagic/enc %d\n", m);
274					goto done;
275				}
276		}
277	}
278
279	/* give up */
280	m = 1;
281	if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
282	    file_printf(ms, mime ? "application/octet-stream" : "data") == -1) {
283	    rv = -1;
284	}
285 done:
286	if ((ms->flags & MAGIC_MIME_ENCODING) != 0) {
287		if (ms->flags & MAGIC_MIME_TYPE)
288			if (file_printf(ms, "; charset=") == -1)
289				rv = -1;
290		if (file_printf(ms, "%s", code_mime) == -1)
291			rv = -1;
292	}
293	free(u8buf);
294	if (rv)
295		return rv;
296
297	return m;
298}
299#endif
300
301protected int
302file_reset(struct magic_set *ms)
303{
304	if (ms->mlist == NULL) {
305		file_error(ms, 0, "no magic files loaded");
306		return -1;
307	}
308	if (ms->o.buf) {
309		free(ms->o.buf);
310		ms->o.buf = NULL;
311	}
312	if (ms->o.pbuf) {
313		free(ms->o.pbuf);
314		ms->o.pbuf = NULL;
315	}
316	ms->event_flags &= ~EVENT_HAD_ERR;
317	ms->error = -1;
318	return 0;
319}
320
321#define OCTALIFY(n, o)	\
322	/*LINTED*/ \
323	(void)(*(n)++ = '\\', \
324	*(n)++ = (((uint32_t)*(o) >> 6) & 3) + '0', \
325	*(n)++ = (((uint32_t)*(o) >> 3) & 7) + '0', \
326	*(n)++ = (((uint32_t)*(o) >> 0) & 7) + '0', \
327	(o)++)
328
329protected const char *
330file_getbuffer(struct magic_set *ms)
331{
332	char *pbuf, *op, *np;
333	size_t psize, len;
334
335	if (ms->event_flags & EVENT_HAD_ERR)
336		return NULL;
337
338	if (ms->flags & MAGIC_RAW)
339		return ms->o.buf;
340
341	if (ms->o.buf == NULL)
342		return NULL;
343
344	/* * 4 is for octal representation, + 1 is for NUL */
345	len = strlen(ms->o.buf);
346	if (len > (SIZE_MAX - 1) / 4) {
347		file_oomem(ms, len);
348		return NULL;
349	}
350	psize = len * 4 + 1;
351	if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) {
352		file_oomem(ms, psize);
353		return NULL;
354	}
355	ms->o.pbuf = pbuf;
356
357#if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
358	{
359		mbstate_t state;
360		wchar_t nextchar;
361		int mb_conv = 1;
362		size_t bytesconsumed;
363		char *eop;
364		(void)memset(&state, 0, sizeof(mbstate_t));
365
366		np = ms->o.pbuf;
367		op = ms->o.buf;
368		eop = op + len;
369
370		while (op < eop) {
371			bytesconsumed = mbrtowc(&nextchar, op,
372			    (size_t)(eop - op), &state);
373			if (bytesconsumed == (size_t)(-1) ||
374			    bytesconsumed == (size_t)(-2)) {
375				mb_conv = 0;
376				break;
377			}
378
379			if (iswprint(nextchar)) {
380				(void)memcpy(np, op, bytesconsumed);
381				op += bytesconsumed;
382				np += bytesconsumed;
383			} else {
384				while (bytesconsumed-- > 0)
385					OCTALIFY(np, op);
386			}
387		}
388		*np = '\0';
389
390		/* Parsing succeeded as a multi-byte sequence */
391		if (mb_conv != 0)
392			return ms->o.pbuf;
393	}
394#endif
395
396	for (np = ms->o.pbuf, op = ms->o.buf; *op;) {
397		if (isprint((unsigned char)*op)) {
398			*np++ = *op++;
399		} else {
400			OCTALIFY(np, op);
401		}
402	}
403	*np = '\0';
404	return ms->o.pbuf;
405}
406
407protected int
408file_check_mem(struct magic_set *ms, unsigned int level)
409{
410	size_t len;
411
412	if (level >= ms->c.len) {
413		len = (ms->c.len += 20) * sizeof(*ms->c.li);
414		ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ?
415		    malloc(len) :
416		    realloc(ms->c.li, len));
417		if (ms->c.li == NULL) {
418			file_oomem(ms, len);
419			return -1;
420		}
421	}
422	ms->c.li[level].got_match = 0;
423#ifdef ENABLE_CONDITIONALS
424	ms->c.li[level].last_match = 0;
425	ms->c.li[level].last_cond = COND_NONE;
426#endif /* ENABLE_CONDITIONALS */
427	return 0;
428}
429
430protected size_t
431file_printedlen(const struct magic_set *ms)
432{
433	return ms->o.buf == NULL ? 0 : strlen(ms->o.buf);
434}
435
436protected int
437file_replace(struct magic_set *ms, const char *pat, const char *rep)
438{
439	regex_t rx;
440	int rc;
441
442	rc = regcomp(&rx, pat, REG_EXTENDED);
443	if (rc) {
444		char errmsg[512];
445		(void)regerror(rc, &rx, errmsg, sizeof(errmsg));
446		file_magerror(ms, "regex error %d, (%s)", rc, errmsg);
447		return -1;
448	} else {
449		regmatch_t rm;
450		int nm = 0;
451		while (regexec(&rx, ms->o.buf, 1, &rm, 0) == 0) {
452			ms->o.buf[rm.rm_so] = '\0';
453			if (file_printf(ms, "%s%s", rep,
454			    rm.rm_eo != 0 ? ms->o.buf + rm.rm_eo : "") == -1)
455				return -1;
456			nm++;
457		}
458		regfree(&rx);
459		return nm;
460	}
461}
462