funcs.c revision 284778 
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 1.82 2015/06/03 18:01:20 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
162
163static int
164checkdone(struct magic_set *ms, int *rv)
165{
166	if ((ms->flags & MAGIC_CONTINUE) == 0)
167		return 1;
168	if (file_printf(ms, "\n- ") == -1)
169		*rv = -1;
170	return 0;
171}
172
173/*ARGSUSED*/
174protected int
175file_buffer(struct magic_set *ms, int fd, const char *inname __attribute__ ((__unused__)),
176    const void *buf, size_t nb)
177{
178	int m = 0, rv = 0, looks_text = 0;
179	int mime = ms->flags & MAGIC_MIME;
180	const unsigned char *ubuf = CAST(const unsigned char *, buf);
181	unichar *u8buf = NULL;
182	size_t ulen;
183	const char *code = NULL;
184	const char *code_mime = "binary";
185	const char *type = "application/octet-stream";
186	const char *def = "data";
187	const char *ftype = NULL;
188
189	if (nb == 0) {
190		def = "empty";
191		type = "application/x-empty";
192		goto simple;
193	} else if (nb == 1) {
194		def = "very short file (no magic)";
195		goto simple;
196	}
197
198	if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) {
199		looks_text = file_encoding(ms, ubuf, nb, &u8buf, &ulen,
200		    &code, &code_mime, &ftype);
201	}
202
203#ifdef __EMX__
204	if ((ms->flags & MAGIC_NO_CHECK_APPTYPE) == 0 && inname) {
205		switch (file_os2_apptype(ms, inname, buf, nb)) {
206		case -1:
207			return -1;
208		case 0:
209			break;
210		default:
211			return 1;
212		}
213	}
214#endif
215#if HAVE_FORK
216	/* try compression stuff */
217	if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) == 0)
218		if ((m = file_zmagic(ms, fd, inname, ubuf, nb)) != 0) {
219			if ((ms->flags & MAGIC_DEBUG) != 0)
220				(void)fprintf(stderr, "zmagic %d\n", m);
221			goto done_encoding;
222		}
223#endif
224	/* Check if we have a tar file */
225	if ((ms->flags & MAGIC_NO_CHECK_TAR) == 0)
226		if ((m = file_is_tar(ms, ubuf, nb)) != 0) {
227			if ((ms->flags & MAGIC_DEBUG) != 0)
228				(void)fprintf(stderr, "tar %d\n", m);
229			if (checkdone(ms, &rv))
230				goto done;
231		}
232
233	/* Check if we have a CDF file */
234	if ((ms->flags & MAGIC_NO_CHECK_CDF) == 0)
235		if ((m = file_trycdf(ms, fd, ubuf, nb)) != 0) {
236			if ((ms->flags & MAGIC_DEBUG) != 0)
237				(void)fprintf(stderr, "cdf %d\n", m);
238			if (checkdone(ms, &rv))
239				goto done;
240		}
241
242	/* try soft magic tests */
243	if ((ms->flags & MAGIC_NO_CHECK_SOFT) == 0)
244		if ((m = file_softmagic(ms, ubuf, nb, 0, NULL, BINTEST,
245		    looks_text)) != 0) {
246			if ((ms->flags & MAGIC_DEBUG) != 0)
247				(void)fprintf(stderr, "softmagic %d\n", m);
248#ifdef BUILTIN_ELF
249			if ((ms->flags & MAGIC_NO_CHECK_ELF) == 0 && m == 1 &&
250			    nb > 5 && fd != -1) {
251				/*
252				 * We matched something in the file, so this
253				 * *might* be an ELF file, and the file is at
254				 * least 5 bytes long, so if it's an ELF file
255				 * it has at least one byte past the ELF magic
256				 * number - try extracting information from the
257				 * ELF headers that cannot easily * be
258				 * extracted with rules in the magic file.
259				 */
260				if ((m = file_tryelf(ms, fd, ubuf, nb)) != 0)
261					if ((ms->flags & MAGIC_DEBUG) != 0)
262						(void)fprintf(stderr,
263						    "elf %d\n", m);
264			}
265#endif
266			if (checkdone(ms, &rv))
267				goto done;
268		}
269
270	/* try text properties */
271	if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) {
272
273		if ((m = file_ascmagic(ms, ubuf, nb, looks_text)) != 0) {
274			if ((ms->flags & MAGIC_DEBUG) != 0)
275				(void)fprintf(stderr, "ascmagic %d\n", m);
276			if (checkdone(ms, &rv))
277				goto done;
278		}
279	}
280
281simple:
282	/* give up */
283	m = 1;
284	if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
285	    file_printf(ms, "%s", mime ? type : def) == -1) {
286	    rv = -1;
287	}
288 done:
289	if ((ms->flags & MAGIC_MIME_ENCODING) != 0) {
290		if (ms->flags & MAGIC_MIME_TYPE)
291			if (file_printf(ms, "; charset=") == -1)
292				rv = -1;
293		if (file_printf(ms, "%s", code_mime) == -1)
294			rv = -1;
295	}
296#if HAVE_FORK
297 done_encoding:
298#endif
299	free(u8buf);
300	if (rv)
301		return rv;
302
303	return m;
304}
305#endif
306
307protected int
308file_reset(struct magic_set *ms)
309{
310	if (ms->mlist[0] == NULL) {
311		file_error(ms, 0, "no magic files loaded");
312		return -1;
313	}
314	if (ms->o.buf) {
315		free(ms->o.buf);
316		ms->o.buf = NULL;
317	}
318	if (ms->o.pbuf) {
319		free(ms->o.pbuf);
320		ms->o.pbuf = NULL;
321	}
322	ms->event_flags &= ~EVENT_HAD_ERR;
323	ms->error = -1;
324	return 0;
325}
326
327#define OCTALIFY(n, o)	\
328	/*LINTED*/ \
329	(void)(*(n)++ = '\\', \
330	*(n)++ = (((uint32_t)*(o) >> 6) & 3) + '0', \
331	*(n)++ = (((uint32_t)*(o) >> 3) & 7) + '0', \
332	*(n)++ = (((uint32_t)*(o) >> 0) & 7) + '0', \
333	(o)++)
334
335protected const char *
336file_getbuffer(struct magic_set *ms)
337{
338	char *pbuf, *op, *np;
339	size_t psize, len;
340
341	if (ms->event_flags & EVENT_HAD_ERR)
342		return NULL;
343
344	if (ms->flags & MAGIC_RAW)
345		return ms->o.buf;
346
347	if (ms->o.buf == NULL)
348		return NULL;
349
350	/* * 4 is for octal representation, + 1 is for NUL */
351	len = strlen(ms->o.buf);
352	if (len > (SIZE_MAX - 1) / 4) {
353		file_oomem(ms, len);
354		return NULL;
355	}
356	psize = len * 4 + 1;
357	if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) {
358		file_oomem(ms, psize);
359		return NULL;
360	}
361	ms->o.pbuf = pbuf;
362
363#if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
364	{
365		mbstate_t state;
366		wchar_t nextchar;
367		int mb_conv = 1;
368		size_t bytesconsumed;
369		char *eop;
370		(void)memset(&state, 0, sizeof(mbstate_t));
371
372		np = ms->o.pbuf;
373		op = ms->o.buf;
374		eop = op + len;
375
376		while (op < eop) {
377			bytesconsumed = mbrtowc(&nextchar, op,
378			    (size_t)(eop - op), &state);
379			if (bytesconsumed == (size_t)(-1) ||
380			    bytesconsumed == (size_t)(-2)) {
381				mb_conv = 0;
382				break;
383			}
384
385			if (iswprint(nextchar)) {
386				(void)memcpy(np, op, bytesconsumed);
387				op += bytesconsumed;
388				np += bytesconsumed;
389			} else {
390				while (bytesconsumed-- > 0)
391					OCTALIFY(np, op);
392			}
393		}
394		*np = '\0';
395
396		/* Parsing succeeded as a multi-byte sequence */
397		if (mb_conv != 0)
398			return ms->o.pbuf;
399	}
400#endif
401
402	for (np = ms->o.pbuf, op = ms->o.buf; *op;) {
403		if (isprint((unsigned char)*op)) {
404			*np++ = *op++;
405		} else {
406			OCTALIFY(np, op);
407		}
408	}
409	*np = '\0';
410	return ms->o.pbuf;
411}
412
413protected int
414file_check_mem(struct magic_set *ms, unsigned int level)
415{
416	size_t len;
417
418	if (level >= ms->c.len) {
419		len = (ms->c.len = 20 + level) * sizeof(*ms->c.li);
420		ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ?
421		    malloc(len) :
422		    realloc(ms->c.li, len));
423		if (ms->c.li == NULL) {
424			file_oomem(ms, len);
425			return -1;
426		}
427	}
428	ms->c.li[level].got_match = 0;
429#ifdef ENABLE_CONDITIONALS
430	ms->c.li[level].last_match = 0;
431	ms->c.li[level].last_cond = COND_NONE;
432#endif /* ENABLE_CONDITIONALS */
433	return 0;
434}
435
436protected size_t
437file_printedlen(const struct magic_set *ms)
438{
439	return ms->o.buf == NULL ? 0 : strlen(ms->o.buf);
440}
441
442protected int
443file_replace(struct magic_set *ms, const char *pat, const char *rep)
444{
445	file_regex_t rx;
446	int rc, rv = -1;
447
448	rc = file_regcomp(&rx, pat, REG_EXTENDED);
449	if (rc) {
450		file_regerror(&rx, rc, ms);
451	} else {
452		regmatch_t rm;
453		int nm = 0;
454		while (file_regexec(&rx, ms->o.buf, 1, &rm, 0) == 0) {
455			ms->o.buf[rm.rm_so] = '\0';
456			if (file_printf(ms, "%s%s", rep,
457			    rm.rm_eo != 0 ? ms->o.buf + rm.rm_eo : "") == -1)
458				goto out;
459			nm++;
460		}
461		rv = nm;
462	}
463out:
464	file_regfree(&rx);
465	return rv;
466}
467
468protected int
469file_regcomp(file_regex_t *rx, const char *pat, int flags)
470{
471#ifdef USE_C_LOCALE
472	rx->c_lc_ctype = newlocale(LC_CTYPE_MASK, "C", 0);
473	assert(rx->c_lc_ctype != NULL);
474	rx->old_lc_ctype = uselocale(rx->c_lc_ctype);
475	assert(rx->old_lc_ctype != NULL);
476#endif
477	rx->pat = pat;
478
479	return rx->rc = regcomp(&rx->rx, pat, flags);
480}
481
482protected int
483file_regexec(file_regex_t *rx, const char *str, size_t nmatch,
484    regmatch_t* pmatch, int eflags)
485{
486	assert(rx->rc == 0);
487	return regexec(&rx->rx, str, nmatch, pmatch, eflags);
488}
489
490protected void
491file_regfree(file_regex_t *rx)
492{
493	if (rx->rc == 0)
494		regfree(&rx->rx);
495#ifdef USE_C_LOCALE
496	(void)uselocale(rx->old_lc_ctype);
497	freelocale(rx->c_lc_ctype);
498#endif
499}
500
501protected void
502file_regerror(file_regex_t *rx, int rc, struct magic_set *ms)
503{
504	char errmsg[512];
505
506	(void)regerror(rc, &rx->rx, errmsg, sizeof(errmsg));
507	file_magerror(ms, "regex error %d for `%s', (%s)", rc, rx->pat,
508	    errmsg);
509}
510
511protected file_pushbuf_t *
512file_push_buffer(struct magic_set *ms)
513{
514	file_pushbuf_t *pb;
515
516	if (ms->event_flags & EVENT_HAD_ERR)
517		return NULL;
518
519	if ((pb = (CAST(file_pushbuf_t *, malloc(sizeof(*pb))))) == NULL)
520		return NULL;
521
522	pb->buf = ms->o.buf;
523	pb->offset = ms->offset;
524
525	ms->o.buf = NULL;
526	ms->offset = 0;
527
528	return pb;
529}
530
531protected char *
532file_pop_buffer(struct magic_set *ms, file_pushbuf_t *pb)
533{
534	char *rbuf;
535
536	if (ms->event_flags & EVENT_HAD_ERR) {
537		free(pb->buf);
538		free(pb);
539		return NULL;
540	}
541
542	rbuf = ms->o.buf;
543
544	ms->o.buf = pb->buf;
545	ms->offset = pb->offset;
546
547	free(pb);
548	return rbuf;
549}
550
551/*
552 * convert string to ascii printable format.
553 */
554protected char *
555file_printable(char *buf, size_t bufsiz, const char *str)
556{
557	char *ptr, *eptr;
558	const unsigned char *s = (const unsigned char *)str;
559
560	for (ptr = buf, eptr = ptr + bufsiz - 1; ptr < eptr && *s; s++) {
561		if (isprint(*s)) {
562			*ptr++ = *s;
563			continue;
564		}
565		if (ptr >= eptr - 3)
566			break;
567		*ptr++ = '\\';
568		*ptr++ = ((CAST(unsigned int, *s) >> 6) & 7) + '0';
569		*ptr++ = ((CAST(unsigned int, *s) >> 3) & 7) + '0';
570		*ptr++ = ((CAST(unsigned int, *s) >> 0) & 7) + '0';
571	}
572	*ptr = '\0';
573	return buf;
574}
575