funcs.c revision 277592 
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 1.79 2014/12/16 20:52:49 christos Exp $")
31#endif	/* lint */
32
33#include "magic.h"
34#include <assert.h>
35#include <stdarg.h>
36#include <stdlib.h>
37#include <string.h>
38#include <ctype.h>
39#if defined(HAVE_WCHAR_H)
40#include <wchar.h>
41#endif
42#if defined(HAVE_WCTYPE_H)
43#include <wctype.h>
44#endif
45#if defined(HAVE_LIMITS_H)
46#include <limits.h>
47#endif
48
49#ifndef SIZE_MAX
50#define SIZE_MAX	((size_t)~0)
51#endif
52
53/*
54 * Like printf, only we append to a buffer.
55 */
56protected int
57file_vprintf(struct magic_set *ms, const char *fmt, va_list ap)
58{
59	int len;
60	char *buf, *newstr;
61
62	if (ms->event_flags & EVENT_HAD_ERR)
63		return 0;
64	len = vasprintf(&buf, fmt, ap);
65	if (len < 0)
66		goto out;
67
68	if (ms->o.buf != NULL) {
69		len = asprintf(&newstr, "%s%s", ms->o.buf, buf);
70		free(buf);
71		if (len < 0)
72			goto out;
73		free(ms->o.buf);
74		buf = newstr;
75	}
76	ms->o.buf = buf;
77	return 0;
78out:
79	file_error(ms, errno, "vasprintf failed");
80	return -1;
81}
82
83protected int
84file_printf(struct magic_set *ms, const char *fmt, ...)
85{
86	int rv;
87	va_list ap;
88
89	va_start(ap, fmt);
90	rv = file_vprintf(ms, fmt, ap);
91	va_end(ap);
92	return rv;
93}
94
95/*
96 * error - print best error message possible
97 */
98/*VARARGS*/
99__attribute__((__format__(__printf__, 3, 0)))
100private void
101file_error_core(struct magic_set *ms, int error, const char *f, va_list va,
102    size_t lineno)
103{
104	/* Only the first error is ok */
105	if (ms->event_flags & EVENT_HAD_ERR)
106		return;
107	if (lineno != 0) {
108		free(ms->o.buf);
109		ms->o.buf = NULL;
110		file_printf(ms, "line %" SIZE_T_FORMAT "u: ", lineno);
111	}
112	file_vprintf(ms, f, va);
113	if (error > 0)
114		file_printf(ms, " (%s)", strerror(error));
115	ms->event_flags |= EVENT_HAD_ERR;
116	ms->error = error;
117}
118
119/*VARARGS*/
120protected void
121file_error(struct magic_set *ms, int error, const char *f, ...)
122{
123	va_list va;
124	va_start(va, f);
125	file_error_core(ms, error, f, va, 0);
126	va_end(va);
127}
128
129/*
130 * Print an error with magic line number.
131 */
132/*VARARGS*/
133protected void
134file_magerror(struct magic_set *ms, const char *f, ...)
135{
136	va_list va;
137	va_start(va, f);
138	file_error_core(ms, 0, f, va, ms->line);
139	va_end(va);
140}
141
142protected void
143file_oomem(struct magic_set *ms, size_t len)
144{
145	file_error(ms, errno, "cannot allocate %" SIZE_T_FORMAT "u bytes",
146	    len);
147}
148
149protected void
150file_badseek(struct magic_set *ms)
151{
152	file_error(ms, errno, "error seeking");
153}
154
155protected void
156file_badread(struct magic_set *ms)
157{
158	file_error(ms, errno, "error reading");
159}
160
161#ifndef COMPILE_ONLY
162protected int
163file_buffer(struct magic_set *ms, int fd, const char *inname __attribute__ ((unused)),
164    const void *buf, size_t nb)
165{
166	int m = 0, rv = 0, looks_text = 0;
167	int mime = ms->flags & MAGIC_MIME;
168	const unsigned char *ubuf = CAST(const unsigned char *, buf);
169	unichar *u8buf = NULL;
170	size_t ulen;
171	const char *code = NULL;
172	const char *code_mime = "binary";
173	const char *type = "application/octet-stream";
174	const char *def = "data";
175	const char *ftype = NULL;
176
177	if (nb == 0) {
178		def = "empty";
179		type = "application/x-empty";
180		goto simple;
181	} else if (nb == 1) {
182		def = "very short file (no magic)";
183		goto simple;
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, &ftype);
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#if HAVE_FORK
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_encoding;
210		}
211#endif
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, 0, NULL, BINTEST,
231		    looks_text)) != 0) {
232			if ((ms->flags & MAGIC_DEBUG) != 0)
233				(void)fprintf(stderr, "softmagic %d\n", m);
234#ifdef BUILTIN_ELF
235			if ((ms->flags & MAGIC_NO_CHECK_ELF) == 0 && m == 1 &&
236			    nb > 5 && fd != -1) {
237				/*
238				 * We matched something in the file, so this
239				 * *might* be an ELF file, and the file is at
240				 * least 5 bytes long, so if it's an ELF file
241				 * it has at least one byte past the ELF magic
242				 * number - try extracting information from the
243				 * ELF headers that cannot easily * be
244				 * extracted with rules in the magic file.
245				 */
246				if ((m = file_tryelf(ms, fd, ubuf, nb)) != 0)
247					if ((ms->flags & MAGIC_DEBUG) != 0)
248						(void)fprintf(stderr,
249						    "elf %d\n", m);
250			}
251#endif
252			goto done;
253		}
254
255	/* try text properties */
256	if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) {
257
258		if ((m = file_ascmagic(ms, ubuf, nb, looks_text)) != 0) {
259			if ((ms->flags & MAGIC_DEBUG) != 0)
260				(void)fprintf(stderr, "ascmagic %d\n", m);
261			goto done;
262		}
263	}
264
265simple:
266	/* give up */
267	m = 1;
268	if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
269	    file_printf(ms, "%s", mime ? type : def) == -1) {
270	    rv = -1;
271	}
272 done:
273	if ((ms->flags & MAGIC_MIME_ENCODING) != 0) {
274		if (ms->flags & MAGIC_MIME_TYPE)
275			if (file_printf(ms, "; charset=") == -1)
276				rv = -1;
277		if (file_printf(ms, "%s", code_mime) == -1)
278			rv = -1;
279	}
280#if HAVE_FORK
281 done_encoding:
282#endif
283	free(u8buf);
284	if (rv)
285		return rv;
286
287	return m;
288}
289#endif
290
291protected int
292file_reset(struct magic_set *ms)
293{
294	if (ms->mlist[0] == NULL) {
295		file_error(ms, 0, "no magic files loaded");
296		return -1;
297	}
298	if (ms->o.buf) {
299		free(ms->o.buf);
300		ms->o.buf = NULL;
301	}
302	if (ms->o.pbuf) {
303		free(ms->o.pbuf);
304		ms->o.pbuf = NULL;
305	}
306	ms->event_flags &= ~EVENT_HAD_ERR;
307	ms->error = -1;
308	return 0;
309}
310
311#define OCTALIFY(n, o)	\
312	/*LINTED*/ \
313	(void)(*(n)++ = '\\', \
314	*(n)++ = (((uint32_t)*(o) >> 6) & 3) + '0', \
315	*(n)++ = (((uint32_t)*(o) >> 3) & 7) + '0', \
316	*(n)++ = (((uint32_t)*(o) >> 0) & 7) + '0', \
317	(o)++)
318
319protected const char *
320file_getbuffer(struct magic_set *ms)
321{
322	char *pbuf, *op, *np;
323	size_t psize, len;
324
325	if (ms->event_flags & EVENT_HAD_ERR)
326		return NULL;
327
328	if (ms->flags & MAGIC_RAW)
329		return ms->o.buf;
330
331	if (ms->o.buf == NULL)
332		return NULL;
333
334	/* * 4 is for octal representation, + 1 is for NUL */
335	len = strlen(ms->o.buf);
336	if (len > (SIZE_MAX - 1) / 4) {
337		file_oomem(ms, len);
338		return NULL;
339	}
340	psize = len * 4 + 1;
341	if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) {
342		file_oomem(ms, psize);
343		return NULL;
344	}
345	ms->o.pbuf = pbuf;
346
347#if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
348	{
349		mbstate_t state;
350		wchar_t nextchar;
351		int mb_conv = 1;
352		size_t bytesconsumed;
353		char *eop;
354		(void)memset(&state, 0, sizeof(mbstate_t));
355
356		np = ms->o.pbuf;
357		op = ms->o.buf;
358		eop = op + len;
359
360		while (op < eop) {
361			bytesconsumed = mbrtowc(&nextchar, op,
362			    (size_t)(eop - op), &state);
363			if (bytesconsumed == (size_t)(-1) ||
364			    bytesconsumed == (size_t)(-2)) {
365				mb_conv = 0;
366				break;
367			}
368
369			if (iswprint(nextchar)) {
370				(void)memcpy(np, op, bytesconsumed);
371				op += bytesconsumed;
372				np += bytesconsumed;
373			} else {
374				while (bytesconsumed-- > 0)
375					OCTALIFY(np, op);
376			}
377		}
378		*np = '\0';
379
380		/* Parsing succeeded as a multi-byte sequence */
381		if (mb_conv != 0)
382			return ms->o.pbuf;
383	}
384#endif
385
386	for (np = ms->o.pbuf, op = ms->o.buf; *op;) {
387		if (isprint((unsigned char)*op)) {
388			*np++ = *op++;
389		} else {
390			OCTALIFY(np, op);
391		}
392	}
393	*np = '\0';
394	return ms->o.pbuf;
395}
396
397protected int
398file_check_mem(struct magic_set *ms, unsigned int level)
399{
400	size_t len;
401
402	if (level >= ms->c.len) {
403		len = (ms->c.len += 20) * sizeof(*ms->c.li);
404		ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ?
405		    malloc(len) :
406		    realloc(ms->c.li, len));
407		if (ms->c.li == NULL) {
408			file_oomem(ms, len);
409			return -1;
410		}
411	}
412	ms->c.li[level].got_match = 0;
413#ifdef ENABLE_CONDITIONALS
414	ms->c.li[level].last_match = 0;
415	ms->c.li[level].last_cond = COND_NONE;
416#endif /* ENABLE_CONDITIONALS */
417	return 0;
418}
419
420protected size_t
421file_printedlen(const struct magic_set *ms)
422{
423	return ms->o.buf == NULL ? 0 : strlen(ms->o.buf);
424}
425
426protected int
427file_replace(struct magic_set *ms, const char *pat, const char *rep)
428{
429	file_regex_t rx;
430	int rc, rv = -1;
431
432	rc = file_regcomp(&rx, pat, REG_EXTENDED);
433	if (rc) {
434		file_regerror(&rx, rc, ms);
435	} else {
436		regmatch_t rm;
437		int nm = 0;
438		while (file_regexec(&rx, ms->o.buf, 1, &rm, 0) == 0) {
439			ms->o.buf[rm.rm_so] = '\0';
440			if (file_printf(ms, "%s%s", rep,
441			    rm.rm_eo != 0 ? ms->o.buf + rm.rm_eo : "") == -1)
442				goto out;
443			nm++;
444		}
445		rv = nm;
446	}
447out:
448	file_regfree(&rx);
449	return rv;
450}
451
452protected int
453file_regcomp(file_regex_t *rx, const char *pat, int flags)
454{
455#ifdef USE_C_LOCALE
456	rx->c_lc_ctype = newlocale(LC_CTYPE_MASK, "C", 0);
457	assert(rx->c_lc_ctype != NULL);
458	rx->old_lc_ctype = uselocale(rx->c_lc_ctype);
459	assert(rx->old_lc_ctype != NULL);
460#endif
461	rx->pat = pat;
462
463	return rx->rc = regcomp(&rx->rx, pat, flags);
464}
465
466protected int
467file_regexec(file_regex_t *rx, const char *str, size_t nmatch,
468    regmatch_t* pmatch, int eflags)
469{
470	assert(rx->rc == 0);
471	return regexec(&rx->rx, str, nmatch, pmatch, eflags);
472}
473
474protected void
475file_regfree(file_regex_t *rx)
476{
477	if (rx->rc == 0)
478		regfree(&rx->rx);
479#ifdef USE_C_LOCALE
480	(void)uselocale(rx->old_lc_ctype);
481	freelocale(rx->c_lc_ctype);
482#endif
483}
484
485protected void
486file_regerror(file_regex_t *rx, int rc, struct magic_set *ms)
487{
488	char errmsg[512];
489
490	(void)regerror(rc, &rx->rx, errmsg, sizeof(errmsg));
491	file_magerror(ms, "regex error %d for `%s', (%s)", rc, rx->pat,
492	    errmsg);
493}
494
495protected file_pushbuf_t *
496file_push_buffer(struct magic_set *ms)
497{
498	file_pushbuf_t *pb;
499
500	if (ms->event_flags & EVENT_HAD_ERR)
501		return NULL;
502
503	if ((pb = (CAST(file_pushbuf_t *, malloc(sizeof(*pb))))) == NULL)
504		return NULL;
505
506	pb->buf = ms->o.buf;
507	pb->offset = ms->offset;
508
509	ms->o.buf = NULL;
510	ms->offset = 0;
511
512	return pb;
513}
514
515protected char *
516file_pop_buffer(struct magic_set *ms, file_pushbuf_t *pb)
517{
518	char *rbuf;
519
520	if (ms->event_flags & EVENT_HAD_ERR) {
521		free(pb->buf);
522		free(pb);
523		return NULL;
524	}
525
526	rbuf = ms->o.buf;
527
528	ms->o.buf = pb->buf;
529	ms->offset = pb->offset;
530
531	free(pb);
532	return rbuf;
533}
534
535/*
536 * convert string to ascii printable format.
537 */
538protected char *
539file_printable(char *buf, size_t bufsiz, const char *str)
540{
541	char *ptr, *eptr;
542	const unsigned char *s = (const unsigned char *)str;
543
544	for (ptr = buf, eptr = ptr + bufsiz - 1; ptr < eptr && *s; s++) {
545		if (isprint(*s)) {
546			*ptr++ = *s;
547			continue;
548		}
549		if (ptr >= eptr - 3)
550			break;
551		*ptr++ = '\\';
552		*ptr++ = ((*s >> 6) & 7) + '0';
553		*ptr++ = ((*s >> 3) & 7) + '0';
554		*ptr++ = ((*s >> 0) & 7) + '0';
555	}
556	*ptr = '\0';
557	return buf;
558}
559