aboutsummaryrefslogtreecommitdiffstats
path: root/wiretap/file_access.c
blob: 08b4d72384c5b09ed8423ef7d075f0c8348c0ffe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
/* file_access.c
 *
 * $Id$
 *
 * Wiretap Library
 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <errno.h>

#ifdef HAVE_IO_H
#include <io.h>	/* open/close on win32 */
#endif

#include "wtap-int.h"
#include "file_wrappers.h"
#include "buffer.h"
#include "lanalyzer.h"
#include "airopeek9.h"
#include "ngsniffer.h"
#include "radcom.h"
#include "ascend.h"
#include "nettl.h"
#include "libpcap.h"
#include "snoop.h"
#include "iptrace.h"
#include "netmon.h"
#include "netxray.h"
#include "toshiba.h"
#include "eyesdn.h"
#include "i4btrace.h"
#include "csids.h"
#include "pppdump.h"
#include "etherpeek.h"
#include "vms.h"
#include "dbs-etherwatch.h"
#include "visual.h"
#include "cosine.h"
#include "5views.h"
#include "erf.h"
#include "hcidump.h"
#include "network_instruments.h"
#include "k12.h"

/* The open_file_* routines should return:
 *
 *	-1 on an I/O error;
 *
 *	1 if the file they're reading is one of the types it handles;
 *
 *	0 if the file they're reading isn't the type they're checking for.
 *
 * If the routine handles this type of file, it should set the "file_type"
 * field in the "struct wtap" to the type of the file.
 *
 * Put the trace files that are merely saved telnet-sessions last, since it's
 * possible that you could have captured someone a router telnet-session
 * using another tool. So, a libpcap trace of an toshiba "snoop" session
 * should be discovered as a libpcap file, not a toshiba file.
 */

static int (*const open_routines[])(wtap *, int *, char **) = {
	/* Files that have magic bytes in fixed locations. These
	 * are easy to identify.
	 */
	libpcap_open,
	lanalyzer_open,
	ngsniffer_open,
	snoop_open,
	iptrace_open,
	netmon_open,
	netxray_open,
	radcom_open,
	nettl_open,
	visual_open,
	_5views_open,
	network_instruments_open,
	airopeek9_open,
	dbs_etherwatch_open,
	k12_open,
	
	/* Files that don't have magic bytes at a fixed location,
	 * but that instead require a heuristic of some sort to
	 * identify them.  This includes the ASCII trace files that
	 * would be, for example, saved copies of a Telnet session
	 * to some box.
	 */
	etherpeek_open,
	pppdump_open,
	ascend_open,
	eyesdn_open,
	toshiba_open,
	i4btrace_open,
	csids_open,
	vms_open,
	cosine_open,
	erf_open,
	hcidump_open,
};

#define	N_FILE_TYPES	(sizeof open_routines / sizeof open_routines[0])

/*
 * Visual C++ on Win32 systems doesn't define these.  (Old UNIX systems don't
 * define them either.)
 *
 * Visual C++ on Win32 systems doesn't define S_IFIFO, it defines _S_IFIFO.
 */
#ifndef S_ISREG
#define S_ISREG(mode)   (((mode) & S_IFMT) == S_IFREG)
#endif
#ifndef S_IFIFO
#define S_IFIFO	_S_IFIFO
#endif
#ifndef S_ISFIFO
#define S_ISFIFO(mode)  (((mode) & S_IFMT) == S_IFIFO)
#endif
#ifndef S_ISDIR
#define S_ISDIR(mode)   (((mode) & S_IFMT) == S_IFDIR)
#endif

/* Opens a file and prepares a wtap struct.
   If "do_random" is TRUE, it opens the file twice; the second open
   allows the application to do random-access I/O without moving
   the seek offset for sequential I/O, which is used by Ethereal
   so that it can do sequential I/O to a capture file that's being
   written to as new packets arrive independently of random I/O done
   to display protocol trees for packets when they're selected. */
wtap* wtap_open_offline(const char *filename, int *err, char **err_info,
    gboolean do_random)
{
	struct stat statb;
	wtap	*wth;
	unsigned int	i;
	gboolean use_stdin = FALSE;

	/* open standard input if filename is '-' */
	if (strcmp(filename, "-") == 0)
		use_stdin = TRUE;

	/* First, make sure the file is valid */
	if (use_stdin) {
		if (fstat(0, &statb) < 0) {
			*err = errno;
			return NULL;
		}
	} else {
		if (stat(filename, &statb) < 0) {
			*err = errno;
			return NULL;
		}
	}
	if (S_ISFIFO(statb.st_mode)) {
		/*
		 * Opens of FIFOs are allowed only when not opening
		 * for random access.
		 *
		 * XXX - currently, we do seeking when trying to find
		 * out the file type, so we don't actually support
		 * opening FIFOs.  However, we may eventually
		 * do buffering that allows us to do at least some
		 * file type determination even on pipes, so we
		 * allow FIFO opens and let things fail later when
		 * we try to seek.
		 */
		if (do_random) {
			*err = WTAP_ERR_RANDOM_OPEN_PIPE;
			return NULL;
		}
	} else if (S_ISDIR(statb.st_mode)) {
		/*
		 * Return different errors for "this is a directory"
		 * and "this is some random special file type", so
		 * the user can get a potentially more helpful error.
		 */
		*err = EISDIR;
		return NULL;
	} else if (! S_ISREG(statb.st_mode)) {
		*err = WTAP_ERR_NOT_REGULAR_FILE;
		return NULL;
	}

	/*
	 * We need two independent descriptors for random access, so
	 * they have different file positions.  If we're opening the
	 * standard input, we can only dup it to get additional
	 * descriptors, so we can't have two independent descriptors,
	 * and thus can't do random access.
	 */
	if (use_stdin && do_random) {
		*err = WTAP_ERR_RANDOM_OPEN_STDIN;
		return NULL;
	}

	errno = ENOMEM;
	wth = g_malloc(sizeof(wtap));
	if (wth == NULL) {
		*err = errno;
		return NULL;
	}

/* Win32 needs the O_BINARY flag for open() */
#ifndef O_BINARY
#define O_BINARY	0
#endif

	/* Open the file */
	errno = WTAP_ERR_CANT_OPEN;
	if (use_stdin) {
		/*
		 * We dup FD 0, so that we don't have to worry about
		 * an fclose or gzclose of wth->fh closing the standard
		 * input of the process.
		 */
		wth->fd = dup(0);
#ifdef _WIN32
		_setmode(wth->fd, O_BINARY);
#endif
	} else
		wth->fd = open(filename, O_RDONLY|O_BINARY);
	if (wth->fd < 0) {
		*err = errno;
		g_free(wth);
		return NULL;
	}
	if (!(wth->fh = filed_open(wth->fd, "rb"))) {
		*err = errno;
		close(wth->fd);
		g_free(wth);
		return NULL;
	}

	if (do_random) {
		if (!(wth->random_fh = file_open(filename, "rb"))) {
			*err = errno;
			file_close(wth->fh);
			g_free(wth);
			return NULL;
		}
	} else
		wth->random_fh = NULL;

	/* initialization */
	wth->file_encap = WTAP_ENCAP_UNKNOWN;
	wth->data_offset = 0;
	wth->subtype_sequential_close = NULL;
	wth->subtype_close = NULL;
	wth->tsprecision = WTAP_FILE_TSPREC_USEC;

	/* Try all file types */
	for (i = 0; i < N_FILE_TYPES; i++) {
		/* Seek back to the beginning of the file; the open routine
		   for the previous file type may have left the file
		   position somewhere other than the beginning, and the
		   open routine for this file type will probably want
		   to start reading at the beginning.

		   Initialize the data offset while we're at it. */
		if (file_seek(wth->fh, 0, SEEK_SET, err) == -1) {
			/* I/O error - give up */
			if (wth->random_fh != NULL)
				file_close(wth->random_fh);
			file_close(wth->fh);
			g_free(wth);
			return NULL;
		}
		wth->data_offset = 0;
		
		switch ((*open_routines[i])(wth, err, err_info)) {

		case -1:
			/* I/O error - give up */
			if (wth->random_fh != NULL)
				file_close(wth->random_fh);
			file_close(wth->fh);
			g_free(wth);
			return NULL;

		case 0:
			/* No I/O error, but not that type of file */
			break;

		case 1:
			/* We found the file type */
			goto success;
		}
	}

	/* Well, it's not one of the types of file we know about. */
	if (wth->random_fh != NULL)
		file_close(wth->random_fh);
	file_close(wth->fh);
	g_free(wth);
	*err = WTAP_ERR_FILE_UNKNOWN_FORMAT;
	return NULL;

success:
	wth->frame_buffer = g_malloc(sizeof(struct Buffer));
	buffer_init(wth->frame_buffer, 1500);
	return wth;
}

/* Table of the file types we know about. */
static const struct file_type_info {
	const char *name;
	const char *short_name;
	gboolean	can_compress;
	int	(*can_write_encap)(int);
	int	(*dump_open)(wtap_dumper *, gboolean, int *);
} dump_open_table[WTAP_NUM_FILE_TYPES] = {
	/* WTAP_FILE_UNKNOWN */
	{ NULL, NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_WTAP */
	{ "Wiretap (Ethereal)", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_PCAP */
	{ "libpcap (tcpdump, Ethereal, etc.)", "libpcap", TRUE,
	  libpcap_dump_can_write_encap, libpcap_dump_open },

	/* WTAP_FILE_PCAP_SS990417 */
	{ "RedHat Linux 6.1 libpcap (tcpdump)", "rh6_1libpcap", TRUE,
	  libpcap_dump_can_write_encap, libpcap_dump_open },

	/* WTAP_FILE_PCAP_SS990915 */
	{ "SuSE Linux 6.3 libpcap (tcpdump)", "suse6_3libpcap", TRUE,
	  libpcap_dump_can_write_encap, libpcap_dump_open },

	/* WTAP_FILE_PCAP_SS991029 */
	{ "modified libpcap (tcpdump)", "modlibpcap", TRUE,
	  libpcap_dump_can_write_encap, libpcap_dump_open },

	/* WTAP_FILE_PCAP_NOKIA */
	{ "Nokia libpcap (tcpdump)", "nokialibpcap", TRUE,
	  libpcap_dump_can_write_encap, libpcap_dump_open },

	/* WTAP_FILE_PCAP_AIX */
	{ "AIX libpcap (tcpdump)", NULL, TRUE,
	  NULL, NULL },

	/* WTAP_FILE_PCAP_NSEC */
	{ "Nanosecond libpcap (Ethereal)", "nseclibpcap", TRUE,
	  libpcap_dump_can_write_encap, libpcap_dump_open },

	/* WTAP_FILE_LANALYZER */
	{ "Novell LANalyzer","lanalyzer", FALSE,
	  lanalyzer_dump_can_write_encap, lanalyzer_dump_open },

	/* WTAP_FILE_NGSNIFFER_UNCOMPRESSED */
	{ "Network Associates Sniffer (DOS-based)", "ngsniffer", FALSE,
	  ngsniffer_dump_can_write_encap, ngsniffer_dump_open },

	/* WTAP_FILE_NGSNIFFER_COMPRESSED */
	{ "Network Associates Sniffer (DOS-based), compressed", "ngsniffer_comp", FALSE,
	  NULL, NULL },

	/* WTAP_FILE_SNOOP */
	{ "Sun snoop", "snoop", FALSE,
	  snoop_dump_can_write_encap, snoop_dump_open },

	/* WTAP_FILE_SHOMITI */
	{ "Shomiti/Finisar Surveyor", "shomiti", FALSE,
	  NULL, NULL },

	/* WTAP_FILE_IPTRACE_1_0 */
	{ "AIX iptrace 1.0", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_IPTRACE_2_0 */
	{ "AIX iptrace 2.0", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_NETMON_1_x */
	{ "Microsoft Network Monitor 1.x", "netmon1", FALSE,
	  netmon_dump_can_write_encap, netmon_dump_open },

	/* WTAP_FILE_NETMON_2_x */
	{ "Microsoft Network Monitor 2.x", "netmon2", FALSE,
	  netmon_dump_can_write_encap, netmon_dump_open },

	/* WTAP_FILE_NETXRAY_OLD */
	{ "Cinco Networks NetXRay 1.x", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_NETXRAY_1_0 */
	{ "Cinco Networks NetXRay 2.0 or later", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_NETXRAY_1_1 */
	{ "Network Associates Sniffer (Windows-based) 1.1", "ngwsniffer_1_1", FALSE,
	  netxray_dump_can_write_encap_1_1, netxray_dump_open_1_1 },

	/* WTAP_FILE_NETXRAY_2_00x */
	{ "Network Associates Sniffer (Windows-based) 2.00x", "ngwsniffer_2_0", FALSE,
	  netxray_dump_can_write_encap_2_0, netxray_dump_open_2_0 },

	/* WTAP_FILE_RADCOM */
	{ "RADCOM WAN/LAN analyzer", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_ASCEND */
	{ "Lucent/Ascend access server trace", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_NETTL */
	{ "HP-UX nettl trace", "nettl", FALSE,
	  nettl_dump_can_write_encap, nettl_dump_open },

	/* WTAP_FILE_TOSHIBA */
	{ "Toshiba Compact ISDN Router snoop trace", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_I4BTRACE */
	{ "I4B ISDN trace", NULL, FALSE,
	  NULL, NULL },

        /* WTAP_FILE_CSIDS */
        { "CSIDS IPLog", NULL, FALSE,
          NULL, NULL },

        /* WTAP_FILE_PPPDUMP */
        { "pppd log (pppdump format)", NULL, FALSE,
          NULL, NULL },

	/* WTAP_FILE_ETHERPEEK_V56 */
	{ "EtherPeek/TokenPeek trace (V5 & V6 file format)", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_ETHERPEEK_V7 */
	{ "EtherPeek/TokenPeek/AiroPeek trace (V7 file format)", NULL, FALSE,
	  NULL, NULL },

	/* WTAP_FILE_VMS */
	{ "TCPIPtrace (VMS)", NULL, FALSE,
	  NULL, NULL},

	/* WTAP_FILE_DBS_ETHERWATCH */
	{ "DBS Etherwatch (VMS)", NULL, FALSE,
	  NULL, NULL},

	/* WTAP_FILE_VISUAL_NETWORKS */
	{ "Visual Networks traffic capture", "visual", FALSE,
	  visual_dump_can_write_encap, visual_dump_open },

	/* WTAP_FILE_COSINE */
	{ "CoSine IPSX L2 capture", "cosine", FALSE,
	  NULL, NULL },

	/* WTAP_FILE_5VIEWS */
	{ "Accellent 5Views capture", "5views", FALSE,
	  _5views_dump_can_write_encap, _5views_dump_open },

	/* WTAP_FILE_ERF */
	{ "Endace DAG capture", "erf", FALSE,
	  NULL, NULL },

	/* WTAP_FILE_HCIDUMP */
	{ "Bluetooth HCI dump", "hcidump", FALSE,
	  NULL, NULL },

	/* WTAP_FILE_NETWORK_INSTRUMENTS_V9 */
	{ "Network Instruments Observer version 9", "niobserverv9", FALSE,
	  network_instruments_dump_can_write_encap, network_instruments_dump_open },

	/* WTAP_FILE_AIROPEEK_V9 */
	{ "EtherPeek/AiroPeek trace (V9 file format)", NULL, FALSE,
	  NULL, NULL },
    
	/* WTAP_FILE_EYESDN */
	{ "EyeSDN USB S0/E1 ISDN trace format", NULL, FALSE,
		NULL, NULL },
    
	/* WTAP_FILE_K12 */
	{ "Tektronix K12xx 32-bit .rf5 format", "rf5", FALSE,
		k12_dump_can_write_encap, k12_dump_open },
};

/* Name that should be somewhat descriptive. */
const char *wtap_file_type_string(int filetype)
{
	if (filetype < 0 || filetype >= WTAP_NUM_FILE_TYPES) {
		g_error("Unknown capture file type %d", filetype);
		return NULL;
	} else
		return dump_open_table[filetype].name;
}

/* Name to use in, say, a command-line flag specifying the type. */
const char *wtap_file_type_short_string(int filetype)
{
	if (filetype < 0 || filetype >= WTAP_NUM_FILE_TYPES)
		return NULL;
	else
		return dump_open_table[filetype].short_name;
}

/* Translate a short name to a capture file type. */
int wtap_short_string_to_file_type(const char *short_name)
{
	int filetype;

	for (filetype = 0; filetype < WTAP_NUM_FILE_TYPES; filetype++) {
		if (dump_open_table[filetype].short_name != NULL &&
		    strcmp(short_name, dump_open_table[filetype].short_name) == 0)
			return filetype;
	}
	return -1;	/* no such file type, or we can't write it */
}

gboolean wtap_dump_can_open(int filetype)
{
	if (filetype < 0 || filetype >= WTAP_NUM_FILE_TYPES
	    || dump_open_table[filetype].dump_open == NULL)
		return FALSE;

	return TRUE;
}

gboolean wtap_dump_can_write_encap(int filetype, int encap)
{
	if (filetype < 0 || filetype >= WTAP_NUM_FILE_TYPES
	    || dump_open_table[filetype].can_write_encap == NULL)
		return FALSE;

	if ((*dump_open_table[filetype].can_write_encap)(encap) != 0)
		return FALSE;

	return TRUE;
}

gboolean wtap_dump_can_compress(int filetype)
{
#ifdef HAVE_LIBZ
	if (filetype < 0 || filetype >= WTAP_NUM_FILE_TYPES
	    || dump_open_table[filetype].can_compress == FALSE)
		return FALSE;

	return TRUE;
#else
	return FALSE;
#endif
}


static gboolean wtap_dump_open_check(int filetype, int encap, gboolean comressed, int *err);
static wtap_dumper* wtap_dump_alloc_wdh(int filetype, int encap, int snaplen,
    gboolean compressed, int *err);
static gboolean wtap_dump_open_finish(wtap_dumper *wdh, int filetype, gboolean compressed, int *err);

static FILE *wtap_dump_file_open(wtap_dumper *wdh, const char *filename);
static FILE *wtap_dump_file_fdopen(wtap_dumper *wdh, int fd);
static int wtap_dump_file_close(wtap_dumper *wdh);

wtap_dumper* wtap_dump_open(const char *filename, int filetype, int encap,
				int snaplen, gboolean compressed, int *err)
{
	wtap_dumper *wdh;
	FILE *fh;

	/* Check whether we can open a capture file with that file type
	   and that encapsulation. */
	if (!wtap_dump_open_check(filetype, encap, compressed, err))
		return NULL;

	/* Allocate a data structure for the output stream. */
	wdh = wtap_dump_alloc_wdh(filetype, encap, snaplen, compressed, err);
	if (wdh == NULL)
		return NULL;	/* couldn't allocate it */

	/* Empty filename means stdout */
	if (*filename == '\0') {
		if(compressed) {
			g_free(wdh);
			return NULL;	/* compress won't work on stdout */
		}
#ifdef _WIN32
		setmode(fileno(stdout), O_BINARY);
#endif
		wdh->fh = stdout;
	} else {
		/* In case "fopen()" fails but doesn't set "errno", set "errno"
		   to a generic "the open failed" error. */
		errno = WTAP_ERR_CANT_OPEN;
		fh = wtap_dump_file_open(wdh, filename);
		if (fh == NULL) {
			*err = errno;
			g_free(wdh);
			return NULL;	/* can't create file */
		}
		wdh->fh = fh;
	}

	if (!wtap_dump_open_finish(wdh, filetype, compressed, err)) {
		/* Get rid of the file we created; we couldn't finish
		   opening it. */
		if (wdh->fh != stdout) {
			wtap_dump_file_close(wdh);
			unlink(filename);
		}
		g_free(wdh);
		return NULL;
	}
	return wdh;
}

wtap_dumper* wtap_dump_fdopen(int fd, int filetype, int encap, int snaplen,
				gboolean compressed, int *err)
{
	wtap_dumper *wdh;
	FILE *fh;

	/* Check whether we can open a capture file with that file type
	   and that encapsulation. */
	if (!wtap_dump_open_check(filetype, encap, compressed, err))
		return NULL;

	/* Allocate a data structure for the output stream. */
	wdh = wtap_dump_alloc_wdh(filetype, encap, snaplen, compressed, err);
	if (wdh == NULL)
		return NULL;	/* couldn't allocate it */

	/* In case "fopen()" fails but doesn't set "errno", set "errno"
	   to a generic "the open failed" error. */
	errno = WTAP_ERR_CANT_OPEN;
	fh = wtap_dump_file_fdopen(wdh, fd);
	if (fh == NULL) {
		*err = errno;
		g_free(wdh);
		return NULL;	/* can't create standard I/O stream */
	}
	wdh->fh = fh;

	if (!wtap_dump_open_finish(wdh, filetype, compressed, err)) {
		wtap_dump_file_close(wdh);
		g_free(wdh);
		return NULL;
	}
	return wdh;
}

static gboolean wtap_dump_open_check(int filetype, int encap, gboolean compressed, int *err)
{
	if (!wtap_dump_can_open(filetype)) {
		/* Invalid type, or type we don't know how to write. */
		*err = WTAP_ERR_UNSUPPORTED_FILE_TYPE;
		return FALSE;
	}

	/* OK, we know how to write that type; can we write the specified
	   encapsulation type? */
	*err = (*dump_open_table[filetype].can_write_encap)(encap);
	if (*err != 0)
		return FALSE;

	/* if compression is wanted, do we support this for this filetype? */
	if(compressed && !wtap_dump_can_compress(filetype)) {
		*err = WTAP_ERR_COMPRESSION_NOT_SUPPORTED;
		return FALSE;
	}

	*err = (*dump_open_table[filetype].can_write_encap)(encap);
	if (*err != 0)
		return FALSE;


	/* All systems go! */
	return TRUE;
}

static wtap_dumper* wtap_dump_alloc_wdh(int filetype, int encap, int snaplen,
					gboolean compressed, int *err)
{
	wtap_dumper *wdh;

	wdh = g_malloc(sizeof (wtap_dumper));
	if (wdh == NULL) {
		*err = errno;
		return NULL;
	}
	wdh->fh = NULL;
	wdh->file_type = filetype;
	wdh->snaplen = snaplen;
	wdh->encap = encap;
	wdh->compressed = compressed;
	wdh->bytes_dumped = 0;
	wdh->dump.opaque = NULL;
	wdh->subtype_write = NULL;
	wdh->subtype_close = NULL;
	return wdh;
}

static gboolean wtap_dump_open_finish(wtap_dumper *wdh, int filetype, gboolean compressed, int *err)
{
	int fd;
	gboolean cant_seek;

	/* Can we do a seek on the file descriptor?
	   If not, note that fact. */
	if(compressed) {
		cant_seek = TRUE;
	} else {
		fd = fileno(wdh->fh);
		if (lseek(fd, 1, SEEK_CUR) == -1)
		  cant_seek = TRUE;
		else {
		  /* Undo the seek. */
		  lseek(fd, 0, SEEK_SET);
		  cant_seek = FALSE;
		}
	}

	/* Now try to open the file for writing. */
	if (!(*dump_open_table[filetype].dump_open)(wdh, cant_seek, err)) {
		return FALSE;
	}

	return TRUE;	/* success! */
}

gboolean wtap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
    const union wtap_pseudo_header *pseudo_header, const guchar *pd, int *err)
{
	return (wdh->subtype_write)(wdh, phdr, pseudo_header, pd, err);
}

void wtap_dump_flush(wtap_dumper *wdh)
{
#ifdef HAVE_LIBZ
	if(wdh->compressed) {
		gzflush(wdh->fh, Z_SYNC_FLUSH);	/* XXX - is Z_SYNC_FLUSH the right one? */
	} else 
#endif
	{
		fflush(wdh->fh);
	}
}

gboolean wtap_dump_close(wtap_dumper *wdh, int *err)
{
	gboolean ret = TRUE;

	if (wdh->subtype_close != NULL) {
		/* There's a close routine for this dump stream. */
		if (!(wdh->subtype_close)(wdh, err))
			ret = FALSE;
	}
	errno = WTAP_ERR_CANT_CLOSE;
	/* Don't close stdout */
	if (wdh->fh != stdout) {
		if (wtap_dump_file_close(wdh) == EOF) {
			if (ret) {
				/* The per-format close function succeeded,
				   but the fclose didn't.  Save the reason
				   why, if our caller asked for it. */
				if (err != NULL)
					*err = errno;
			}
			ret = FALSE;
		}
	}
	if (wdh->dump.opaque != NULL)
		g_free(wdh->dump.opaque);
	g_free(wdh);
	return ret;
}

long wtap_get_bytes_dumped(wtap_dumper *wdh)
{
	return wdh->bytes_dumped;
}

void wtap_set_bytes_dumped(wtap_dumper *wdh, long bytes_dumped)
{
	wdh->bytes_dumped = bytes_dumped;
}


/* internally open a file for writing (compressed or not) */
static FILE *wtap_dump_file_open(wtap_dumper *wdh, const char *filename)
{
#ifdef HAVE_LIBZ
	if(wdh->compressed) {
		return gzopen(filename, "wb");
	} else 
#endif
	{
		return fopen(filename, "wb");
	}
}

/* internally open a file for writing (compressed or not) */
static FILE *wtap_dump_file_fdopen(wtap_dumper *wdh, int fd)
{
#ifdef HAVE_LIBZ
	if(wdh->compressed) {
		return gzdopen(fd, "wb");
	} else 
#endif
	{
		return fdopen(fd, "wb");
	}
}

/* internally writing raw bytes (compressed or not) */
size_t wtap_dump_file_write(wtap_dumper *wdh, const void *buf, unsigned bufsize)
{
#ifdef HAVE_LIBZ
	if(wdh->compressed) {
		return gzwrite(wdh->fh, buf, bufsize);
	} else 
#endif
	{
		return fwrite(buf, 1, bufsize, wdh->fh);
	}
}

/* internally close a file for writing (compressed or not) */
static int wtap_dump_file_close(wtap_dumper *wdh)
{
#ifdef HAVE_LIBZ
	if(wdh->compressed) {
		return gzclose(wdh->fh);
	} else 
#endif
	{
		return fclose(wdh->fh);
	}
}

int wtap_dump_file_ferror(wtap_dumper *wdh)
{
#ifdef HAVE_LIBZ
	int errnum;

	if(wdh->compressed) {
		gzerror(wdh->fh, &errnum);

		if(errnum == Z_ERRNO) {
			return errno;
		} else {
			/* XXX - what to do with this zlib specific number? */
			return errnum;
		}
	} else 
#endif
	{
		return ferror(wdh->fh);
	}
}