funcs.c revision 290152 
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 1.84 2015/09/10 13:32:19 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	if (ms->o.buf && *ms->o.buf)
113		file_printf(ms, " ");
114	file_vprintf(ms, f, va);
115	if (error > 0)
116		file_printf(ms, " (%s)", strerror(error));
117	ms->event_flags |= EVENT_HAD_ERR;
118	ms->error = error;
119}
120
121/*VARARGS*/
122protected void
123file_error(struct magic_set *ms, int error, const char *f, ...)
124{
125	va_list va;
126	va_start(va, f);
127	file_error_core(ms, error, f, va, 0);
128	va_end(va);
129}
130
131/*
132 * Print an error with magic line number.
133 */
134/*VARARGS*/
135protected void
136file_magerror(struct magic_set *ms, const char *f, ...)
137{
138	va_list va;
139	va_start(va, f);
140	file_error_core(ms, 0, f, va, ms->line);
141	va_end(va);
142}
143
144protected void
145file_oomem(struct magic_set *ms, size_t len)
146{
147	file_error(ms, errno, "cannot allocate %" SIZE_T_FORMAT "u bytes",
148	    len);
149}
150
151protected void
152file_badseek(struct magic_set *ms)
153{
154	file_error(ms, errno, "error seeking");
155}
156
157protected void
158file_badread(struct magic_set *ms)
159{
160	file_error(ms, errno, "error reading");
161}
162
163#ifndef COMPILE_ONLY
164
165static int
166checkdone(struct magic_set *ms, int *rv)
167{
168	if ((ms->flags & MAGIC_CONTINUE) == 0)
169		return 1;
170	if (file_printf(ms, "\n- ") == -1)
171		*rv = -1;
172	return 0;
173}
174
175/*ARGSUSED*/
176protected int
177file_buffer(struct magic_set *ms, int fd, const char *inname __attribute__ ((__unused__)),
178    const void *buf, size_t nb)
179{
180	int m = 0, rv = 0, looks_text = 0;
181	int mime = ms->flags & MAGIC_MIME;
182	const unsigned char *ubuf = CAST(const unsigned char *, buf);
183	unichar *u8buf = NULL;
184	size_t ulen;
185	const char *code = NULL;
186	const char *code_mime = "binary";
187	const char *type = "application/octet-stream";
188	const char *def = "data";
189	const char *ftype = NULL;
190
191	if (nb == 0) {
192		def = "empty";
193		type = "application/x-empty";
194		goto simple;
195	} else if (nb == 1) {
196		def = "very short file (no magic)";
197		goto simple;
198	}
199
200	if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
201		looks_text = file_encoding(ms, ubuf, nb, &u8buf, &ulen,
202		    &code, &code_mime, &ftype);
203	}
204
205#ifdef __EMX__
206	if ((ms->flags & MAGIC_NO_CHECK_APPTYPE) == 0 && inname) {
207		m = file_os2_apptype(ms, inname, buf, nb);
208		if ((ms->flags & MAGIC_DEBUG) != 0)
209			(void)fprintf(stderr, "[try os2_apptype %d]\n", m);
210		switch (m) {
211		case -1:
212			return -1;
213		case 0:
214			break;
215		default:
216			return 1;
217		}
218	}
219#endif
220#if HAVE_FORK
221	/* try compression stuff */
222	if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) == 0) {
223		m = file_zmagic(ms, fd, inname, ubuf, nb);
224		if ((ms->flags & MAGIC_DEBUG) != 0)
225			(void)fprintf(stderr, "[try zmagic %d]\n", m);
226		if (m) {
227			goto done_encoding;
228		}
229	}
230#endif
231	/* Check if we have a tar file */
232	if ((ms->flags & MAGIC_NO_CHECK_TAR) == 0) {
233		m = file_is_tar(ms, ubuf, nb);
234		if ((ms->flags & MAGIC_DEBUG) != 0)
235			(void)fprintf(stderr, "[try tar %d]\n", m);
236		if (m) {
237			if (checkdone(ms, &rv))
238				goto done;
239		}
240	}
241
242	/* Check if we have a CDF file */
243	if ((ms->flags & MAGIC_NO_CHECK_CDF) == 0) {
244		m = file_trycdf(ms, fd, ubuf, nb);
245		if ((ms->flags & MAGIC_DEBUG) != 0)
246			(void)fprintf(stderr, "[try cdf %d]\n", m);
247		if (m) {
248			if (checkdone(ms, &rv))
249				goto done;
250		}
251	}
252
253	/* try soft magic tests */
254	if ((ms->flags & MAGIC_NO_CHECK_SOFT) == 0)
255		m = file_softmagic(ms, ubuf, nb, 0, NULL, BINTEST, looks_text);
256		if ((ms->flags & MAGIC_DEBUG) != 0)
257			(void)fprintf(stderr, "[try softmagic %d]\n", m);
258		if (m) {
259#ifdef BUILTIN_ELF
260			if ((ms->flags & MAGIC_NO_CHECK_ELF) == 0 && m == 1 &&
261			    nb > 5 && fd != -1) {
262				/*
263				 * We matched something in the file, so this
264				 * *might* be an ELF file, and the file is at
265				 * least 5 bytes long, so if it's an ELF file
266				 * it has at least one byte past the ELF magic
267				 * number - try extracting information from the
268				 * ELF headers that cannot easily * be
269				 * extracted with rules in the magic file.
270				 */
271				m = file_tryelf(ms, fd, ubuf, nb);
272				if ((ms->flags & MAGIC_DEBUG) != 0)
273					(void)fprintf(stderr, "[try elf %d]\n",
274					    m);
275			}
276#endif
277			if (checkdone(ms, &rv))
278				goto done;
279		}
280
281	/* try text properties */
282	if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) {
283
284		m = file_ascmagic(ms, ubuf, nb, looks_text);
285		if ((ms->flags & MAGIC_DEBUG) != 0)
286			(void)fprintf(stderr, "[try ascmagic %d]\n", m);
287		if (m) {
288			if (checkdone(ms, &rv))
289				goto done;
290		}
291	}
292
293simple:
294	/* give up */
295	m = 1;
296	if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
297	    file_printf(ms, "%s", mime ? type : def) == -1) {
298	    rv = -1;
299	}
300 done:
301	if ((ms->flags & MAGIC_MIME_ENCODING) != 0) {
302		if (ms->flags & MAGIC_MIME_TYPE)
303			if (file_printf(ms, "; charset=") == -1)
304				rv = -1;
305		if (file_printf(ms, "%s", code_mime) == -1)
306			rv = -1;
307	}
308#if HAVE_FORK
309 done_encoding:
310#endif
311	free(u8buf);
312	if (rv)
313		return rv;
314
315	return m;
316}
317#endif
318
319protected int
320file_reset(struct magic_set *ms)
321{
322	if (ms->mlist[0] == NULL) {
323		file_error(ms, 0, "no magic files loaded");
324		return -1;
325	}
326	if (ms->o.buf) {
327		free(ms->o.buf);
328		ms->o.buf = NULL;
329	}
330	if (ms->o.pbuf) {
331		free(ms->o.pbuf);
332		ms->o.pbuf = NULL;
333	}
334	ms->event_flags &= ~EVENT_HAD_ERR;
335	ms->error = -1;
336	return 0;
337}
338
339#define OCTALIFY(n, o)	\
340	/*LINTED*/ \
341	(void)(*(n)++ = '\\', \
342	*(n)++ = (((uint32_t)*(o) >> 6) & 3) + '0', \
343	*(n)++ = (((uint32_t)*(o) >> 3) & 7) + '0', \
344	*(n)++ = (((uint32_t)*(o) >> 0) & 7) + '0', \
345	(o)++)
346
347protected const char *
348file_getbuffer(struct magic_set *ms)
349{
350	char *pbuf, *op, *np;
351	size_t psize, len;
352
353	if (ms->event_flags & EVENT_HAD_ERR)
354		return NULL;
355
356	if (ms->flags & MAGIC_RAW)
357		return ms->o.buf;
358
359	if (ms->o.buf == NULL)
360		return NULL;
361
362	/* * 4 is for octal representation, + 1 is for NUL */
363	len = strlen(ms->o.buf);
364	if (len > (SIZE_MAX - 1) / 4) {
365		file_oomem(ms, len);
366		return NULL;
367	}
368	psize = len * 4 + 1;
369	if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) {
370		file_oomem(ms, psize);
371		return NULL;
372	}
373	ms->o.pbuf = pbuf;
374
375#if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
376	{
377		mbstate_t state;
378		wchar_t nextchar;
379		int mb_conv = 1;
380		size_t bytesconsumed;
381		char *eop;
382		(void)memset(&state, 0, sizeof(mbstate_t));
383
384		np = ms->o.pbuf;
385		op = ms->o.buf;
386		eop = op + len;
387
388		while (op < eop) {
389			bytesconsumed = mbrtowc(&nextchar, op,
390			    (size_t)(eop - op), &state);
391			if (bytesconsumed == (size_t)(-1) ||
392			    bytesconsumed == (size_t)(-2)) {
393				mb_conv = 0;
394				break;
395			}
396
397			if (iswprint(nextchar)) {
398				(void)memcpy(np, op, bytesconsumed);
399				op += bytesconsumed;
400				np += bytesconsumed;
401			} else {
402				while (bytesconsumed-- > 0)
403					OCTALIFY(np, op);
404			}
405		}
406		*np = '\0';
407
408		/* Parsing succeeded as a multi-byte sequence */
409		if (mb_conv != 0)
410			return ms->o.pbuf;
411	}
412#endif
413
414	for (np = ms->o.pbuf, op = ms->o.buf; *op;) {
415		if (isprint((unsigned char)*op)) {
416			*np++ = *op++;
417		} else {
418			OCTALIFY(np, op);
419		}
420	}
421	*np = '\0';
422	return ms->o.pbuf;
423}
424
425protected int
426file_check_mem(struct magic_set *ms, unsigned int level)
427{
428	size_t len;
429
430	if (level >= ms->c.len) {
431		len = (ms->c.len = 20 + level) * sizeof(*ms->c.li);
432		ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ?
433		    malloc(len) :
434		    realloc(ms->c.li, len));
435		if (ms->c.li == NULL) {
436			file_oomem(ms, len);
437			return -1;
438		}
439	}
440	ms->c.li[level].got_match = 0;
441#ifdef ENABLE_CONDITIONALS
442	ms->c.li[level].last_match = 0;
443	ms->c.li[level].last_cond = COND_NONE;
444#endif /* ENABLE_CONDITIONALS */
445	return 0;
446}
447
448protected size_t
449file_printedlen(const struct magic_set *ms)
450{
451	return ms->o.buf == NULL ? 0 : strlen(ms->o.buf);
452}
453
454protected int
455file_replace(struct magic_set *ms, const char *pat, const char *rep)
456{
457	file_regex_t rx;
458	int rc, rv = -1;
459
460	rc = file_regcomp(&rx, pat, REG_EXTENDED);
461	if (rc) {
462		file_regerror(&rx, rc, ms);
463	} else {
464		regmatch_t rm;
465		int nm = 0;
466		while (file_regexec(&rx, ms->o.buf, 1, &rm, 0) == 0) {
467			ms->o.buf[rm.rm_so] = '\0';
468			if (file_printf(ms, "%s%s", rep,
469			    rm.rm_eo != 0 ? ms->o.buf + rm.rm_eo : "") == -1)
470				goto out;
471			nm++;
472		}
473		rv = nm;
474	}
475out:
476	file_regfree(&rx);
477	return rv;
478}
479
480protected int
481file_regcomp(file_regex_t *rx, const char *pat, int flags)
482{
483#ifdef USE_C_LOCALE
484	rx->c_lc_ctype = newlocale(LC_CTYPE_MASK, "C", 0);
485	assert(rx->c_lc_ctype != NULL);
486	rx->old_lc_ctype = uselocale(rx->c_lc_ctype);
487	assert(rx->old_lc_ctype != NULL);
488#endif
489	rx->pat = pat;
490
491	return rx->rc = regcomp(&rx->rx, pat, flags);
492}
493
494protected int
495file_regexec(file_regex_t *rx, const char *str, size_t nmatch,
496    regmatch_t* pmatch, int eflags)
497{
498	assert(rx->rc == 0);
499	return regexec(&rx->rx, str, nmatch, pmatch, eflags);
500}
501
502protected void
503file_regfree(file_regex_t *rx)
504{
505	if (rx->rc == 0)
506		regfree(&rx->rx);
507#ifdef USE_C_LOCALE
508	(void)uselocale(rx->old_lc_ctype);
509	freelocale(rx->c_lc_ctype);
510#endif
511}
512
513protected void
514file_regerror(file_regex_t *rx, int rc, struct magic_set *ms)
515{
516	char errmsg[512];
517
518	(void)regerror(rc, &rx->rx, errmsg, sizeof(errmsg));
519	file_magerror(ms, "regex error %d for `%s', (%s)", rc, rx->pat,
520	    errmsg);
521}
522
523protected file_pushbuf_t *
524file_push_buffer(struct magic_set *ms)
525{
526	file_pushbuf_t *pb;
527
528	if (ms->event_flags & EVENT_HAD_ERR)
529		return NULL;
530
531	if ((pb = (CAST(file_pushbuf_t *, malloc(sizeof(*pb))))) == NULL)
532		return NULL;
533
534	pb->buf = ms->o.buf;
535	pb->offset = ms->offset;
536
537	ms->o.buf = NULL;
538	ms->offset = 0;
539
540	return pb;
541}
542
543protected char *
544file_pop_buffer(struct magic_set *ms, file_pushbuf_t *pb)
545{
546	char *rbuf;
547
548	if (ms->event_flags & EVENT_HAD_ERR) {
549		free(pb->buf);
550		free(pb);
551		return NULL;
552	}
553
554	rbuf = ms->o.buf;
555
556	ms->o.buf = pb->buf;
557	ms->offset = pb->offset;
558
559	free(pb);
560	return rbuf;
561}
562
563/*
564 * convert string to ascii printable format.
565 */
566protected char *
567file_printable(char *buf, size_t bufsiz, const char *str)
568{
569	char *ptr, *eptr;
570	const unsigned char *s = (const unsigned char *)str;
571
572	for (ptr = buf, eptr = ptr + bufsiz - 1; ptr < eptr && *s; s++) {
573		if (isprint(*s)) {
574			*ptr++ = *s;
575			continue;
576		}
577		if (ptr >= eptr - 3)
578			break;
579		*ptr++ = '\\';
580		*ptr++ = ((CAST(unsigned int, *s) >> 6) & 7) + '0';
581		*ptr++ = ((CAST(unsigned int, *s) >> 3) & 7) + '0';
582		*ptr++ = ((CAST(unsigned int, *s) >> 0) & 7) + '0';
583	}
584	*ptr = '\0';
585	return buf;
586}
587