funcs.c revision 328875 
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 1.93 2017/08/28 13:39:18 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	fprintf(stderr, "vasprintf failed (%s)", strerror(errno));
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	const unsigned char *ubuf = CAST(const unsigned char *, buf);
182	unichar *u8buf = NULL;
183	size_t ulen;
184	const char *code = NULL;
185	const char *code_mime = "binary";
186	const char *type = "application/octet-stream";
187	const char *def = "data";
188	const char *ftype = NULL;
189
190	if (nb == 0) {
191		def = "empty";
192		type = "application/x-empty";
193		goto simple;
194	} else if (nb == 1) {
195		def = "very short file (no magic)";
196		goto simple;
197	}
198
199	if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
200		looks_text = file_encoding(ms, ubuf, nb, &u8buf, &ulen,
201		    &code, &code_mime, &ftype);
202	}
203
204#ifdef __EMX__
205	if ((ms->flags & MAGIC_NO_CHECK_APPTYPE) == 0 && inname) {
206		m = file_os2_apptype(ms, inname, buf, nb);
207		if ((ms->flags & MAGIC_DEBUG) != 0)
208			(void)fprintf(stderr, "[try os2_apptype %d]\n", m);
209		switch (m) {
210		case -1:
211			return -1;
212		case 0:
213			break;
214		default:
215			return 1;
216		}
217	}
218#endif
219#if HAVE_FORK
220	/* try compression stuff */
221	if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) == 0) {
222		m = file_zmagic(ms, fd, inname, ubuf, nb);
223		if ((ms->flags & MAGIC_DEBUG) != 0)
224			(void)fprintf(stderr, "[try zmagic %d]\n", m);
225		if (m) {
226			goto done_encoding;
227		}
228	}
229#endif
230	/* Check if we have a tar file */
231	if ((ms->flags & MAGIC_NO_CHECK_TAR) == 0) {
232		m = file_is_tar(ms, ubuf, nb);
233		if ((ms->flags & MAGIC_DEBUG) != 0)
234			(void)fprintf(stderr, "[try tar %d]\n", m);
235		if (m) {
236			if (checkdone(ms, &rv))
237				goto done;
238		}
239	}
240
241	/* Check if we have a CDF file */
242	if ((ms->flags & MAGIC_NO_CHECK_CDF) == 0) {
243		m = file_trycdf(ms, fd, ubuf, nb);
244		if ((ms->flags & MAGIC_DEBUG) != 0)
245			(void)fprintf(stderr, "[try cdf %d]\n", m);
246		if (m) {
247			if (checkdone(ms, &rv))
248				goto done;
249		}
250	}
251
252	/* try soft magic tests */
253	if ((ms->flags & MAGIC_NO_CHECK_SOFT) == 0) {
254		m = file_softmagic(ms, ubuf, nb, NULL, NULL, BINTEST,
255		    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
282	/* try text properties */
283	if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) {
284
285		m = file_ascmagic(ms, ubuf, nb, looks_text);
286		if ((ms->flags & MAGIC_DEBUG) != 0)
287			(void)fprintf(stderr, "[try ascmagic %d]\n", m);
288		if (m) {
289			if (checkdone(ms, &rv))
290				goto done;
291		}
292	}
293
294simple:
295	/* give up */
296	m = 1;
297	if (ms->flags & MAGIC_MIME) {
298		if ((ms->flags & MAGIC_MIME_TYPE) &&
299		    file_printf(ms, "%s", type) == -1)
300			rv = -1;
301	} else if (ms->flags & MAGIC_APPLE) {
302		if (file_printf(ms, "UNKNUNKN") == -1)
303			rv = -1;
304	} else if (ms->flags & MAGIC_EXTENSION) {
305		if (file_printf(ms, "???") == -1)
306			rv = -1;
307	} else {
308		if (file_printf(ms, "%s", def) == -1)
309			rv = -1;
310	}
311 done:
312	if ((ms->flags & MAGIC_MIME_ENCODING) != 0) {
313		if (ms->flags & MAGIC_MIME_TYPE)
314			if (file_printf(ms, "; charset=") == -1)
315				rv = -1;
316		if (file_printf(ms, "%s", code_mime) == -1)
317			rv = -1;
318	}
319#if HAVE_FORK
320 done_encoding:
321#endif
322	free(u8buf);
323	if (rv)
324		return rv;
325
326	return m;
327}
328#endif
329
330protected int
331file_reset(struct magic_set *ms, int checkloaded)
332{
333	if (checkloaded && ms->mlist[0] == NULL) {
334		file_error(ms, 0, "no magic files loaded");
335		return -1;
336	}
337	if (ms->o.buf) {
338		free(ms->o.buf);
339		ms->o.buf = NULL;
340	}
341	if (ms->o.pbuf) {
342		free(ms->o.pbuf);
343		ms->o.pbuf = NULL;
344	}
345	ms->event_flags &= ~EVENT_HAD_ERR;
346	ms->error = -1;
347	return 0;
348}
349
350#define OCTALIFY(n, o)	\
351	/*LINTED*/ \
352	(void)(*(n)++ = '\\', \
353	*(n)++ = (((uint32_t)*(o) >> 6) & 3) + '0', \
354	*(n)++ = (((uint32_t)*(o) >> 3) & 7) + '0', \
355	*(n)++ = (((uint32_t)*(o) >> 0) & 7) + '0', \
356	(o)++)
357
358protected const char *
359file_getbuffer(struct magic_set *ms)
360{
361	char *pbuf, *op, *np;
362	size_t psize, len;
363
364	if (ms->event_flags & EVENT_HAD_ERR)
365		return NULL;
366
367	if (ms->flags & MAGIC_RAW)
368		return ms->o.buf;
369
370	if (ms->o.buf == NULL)
371		return NULL;
372
373	/* * 4 is for octal representation, + 1 is for NUL */
374	len = strlen(ms->o.buf);
375	if (len > (SIZE_MAX - 1) / 4) {
376		file_oomem(ms, len);
377		return NULL;
378	}
379	psize = len * 4 + 1;
380	if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) {
381		file_oomem(ms, psize);
382		return NULL;
383	}
384	ms->o.pbuf = pbuf;
385
386#if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
387	{
388		mbstate_t state;
389		wchar_t nextchar;
390		int mb_conv = 1;
391		size_t bytesconsumed;
392		char *eop;
393		(void)memset(&state, 0, sizeof(mbstate_t));
394
395		np = ms->o.pbuf;
396		op = ms->o.buf;
397		eop = op + len;
398
399		while (op < eop) {
400			bytesconsumed = mbrtowc(&nextchar, op,
401			    (size_t)(eop - op), &state);
402			if (bytesconsumed == (size_t)(-1) ||
403			    bytesconsumed == (size_t)(-2)) {
404				mb_conv = 0;
405				break;
406			}
407
408			if (iswprint(nextchar)) {
409				(void)memcpy(np, op, bytesconsumed);
410				op += bytesconsumed;
411				np += bytesconsumed;
412			} else {
413				while (bytesconsumed-- > 0)
414					OCTALIFY(np, op);
415			}
416		}
417		*np = '\0';
418
419		/* Parsing succeeded as a multi-byte sequence */
420		if (mb_conv != 0)
421			return ms->o.pbuf;
422	}
423#endif
424
425	for (np = ms->o.pbuf, op = ms->o.buf; *op;) {
426		if (isprint((unsigned char)*op)) {
427			*np++ = *op++;
428		} else {
429			OCTALIFY(np, op);
430		}
431	}
432	*np = '\0';
433	return ms->o.pbuf;
434}
435
436protected int
437file_check_mem(struct magic_set *ms, unsigned int level)
438{
439	size_t len;
440
441	if (level >= ms->c.len) {
442		len = (ms->c.len = 20 + level) * sizeof(*ms->c.li);
443		ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ?
444		    malloc(len) :
445		    realloc(ms->c.li, len));
446		if (ms->c.li == NULL) {
447			file_oomem(ms, len);
448			return -1;
449		}
450	}
451	ms->c.li[level].got_match = 0;
452#ifdef ENABLE_CONDITIONALS
453	ms->c.li[level].last_match = 0;
454	ms->c.li[level].last_cond = COND_NONE;
455#endif /* ENABLE_CONDITIONALS */
456	return 0;
457}
458
459protected size_t
460file_printedlen(const struct magic_set *ms)
461{
462	return ms->o.buf == NULL ? 0 : strlen(ms->o.buf);
463}
464
465protected int
466file_replace(struct magic_set *ms, const char *pat, const char *rep)
467{
468	file_regex_t rx;
469	int rc, rv = -1;
470
471	rc = file_regcomp(&rx, pat, REG_EXTENDED);
472	if (rc) {
473		file_regerror(&rx, rc, ms);
474	} else {
475		regmatch_t rm;
476		int nm = 0;
477		while (file_regexec(&rx, ms->o.buf, 1, &rm, 0) == 0) {
478			ms->o.buf[rm.rm_so] = '\0';
479			if (file_printf(ms, "%s%s", rep,
480			    rm.rm_eo != 0 ? ms->o.buf + rm.rm_eo : "") == -1)
481				goto out;
482			nm++;
483		}
484		rv = nm;
485	}
486out:
487	file_regfree(&rx);
488	return rv;
489}
490
491protected int
492file_regcomp(file_regex_t *rx, const char *pat, int flags)
493{
494#ifdef USE_C_LOCALE
495	rx->c_lc_ctype = newlocale(LC_CTYPE_MASK, "C", 0);
496	assert(rx->c_lc_ctype != NULL);
497	rx->old_lc_ctype = uselocale(rx->c_lc_ctype);
498	assert(rx->old_lc_ctype != NULL);
499#else
500	rx->old_lc_ctype = setlocale(LC_CTYPE, "C");
501#endif
502	rx->pat = pat;
503
504	return rx->rc = regcomp(&rx->rx, pat, flags);
505}
506
507protected int
508file_regexec(file_regex_t *rx, const char *str, size_t nmatch,
509    regmatch_t* pmatch, int eflags)
510{
511	assert(rx->rc == 0);
512	/* XXX: force initialization because glibc does not always do this */
513	memset(pmatch, 0, nmatch * sizeof(*pmatch));
514	return regexec(&rx->rx, str, nmatch, pmatch, eflags);
515}
516
517protected void
518file_regfree(file_regex_t *rx)
519{
520	if (rx->rc == 0)
521		regfree(&rx->rx);
522#ifdef USE_C_LOCALE
523	(void)uselocale(rx->old_lc_ctype);
524	freelocale(rx->c_lc_ctype);
525#else
526	(void)setlocale(LC_CTYPE, rx->old_lc_ctype);
527#endif
528}
529
530protected void
531file_regerror(file_regex_t *rx, int rc, struct magic_set *ms)
532{
533	char errmsg[512];
534
535	(void)regerror(rc, &rx->rx, errmsg, sizeof(errmsg));
536	file_magerror(ms, "regex error %d for `%s', (%s)", rc, rx->pat,
537	    errmsg);
538}
539
540protected file_pushbuf_t *
541file_push_buffer(struct magic_set *ms)
542{
543	file_pushbuf_t *pb;
544
545	if (ms->event_flags & EVENT_HAD_ERR)
546		return NULL;
547
548	if ((pb = (CAST(file_pushbuf_t *, malloc(sizeof(*pb))))) == NULL)
549		return NULL;
550
551	pb->buf = ms->o.buf;
552	pb->offset = ms->offset;
553
554	ms->o.buf = NULL;
555	ms->offset = 0;
556
557	return pb;
558}
559
560protected char *
561file_pop_buffer(struct magic_set *ms, file_pushbuf_t *pb)
562{
563	char *rbuf;
564
565	if (ms->event_flags & EVENT_HAD_ERR) {
566		free(pb->buf);
567		free(pb);
568		return NULL;
569	}
570
571	rbuf = ms->o.buf;
572
573	ms->o.buf = pb->buf;
574	ms->offset = pb->offset;
575
576	free(pb);
577	return rbuf;
578}
579
580/*
581 * convert string to ascii printable format.
582 */
583protected char *
584file_printable(char *buf, size_t bufsiz, const char *str)
585{
586	char *ptr, *eptr;
587	const unsigned char *s = (const unsigned char *)str;
588
589	for (ptr = buf, eptr = ptr + bufsiz - 1; ptr < eptr && *s; s++) {
590		if (isprint(*s)) {
591			*ptr++ = *s;
592			continue;
593		}
594		if (ptr >= eptr - 3)
595			break;
596		*ptr++ = '\\';
597		*ptr++ = ((CAST(unsigned int, *s) >> 6) & 7) + '0';
598		*ptr++ = ((CAST(unsigned int, *s) >> 3) & 7) + '0';
599		*ptr++ = ((CAST(unsigned int, *s) >> 0) & 7) + '0';
600	}
601	*ptr = '\0';
602	return buf;
603}
604