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
|
/* file_wrappers.c
*
* $Id: file_wrappers.c,v 1.11 2002/06/07 07:27:34 guy Exp $
*
* 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
/*
* OK, now this is tricky.
*
* At least on FreeBSD 3.2, "/usr/include/zlib.h" includes
* "/usr/include/zconf.h", which, if HAVE_UNISTD_H is defined,
* #defines "z_off_t" to be "off_t", and if HAVE_UNISTD_H is
* not defines, #defines "z_off_t" to be "long" if it's not
* already #defined.
*
* In 4.4-Lite-derived systems such as FreeBSD, "off_t" is
* "long long int", not "long int", so the definition of "z_off_t" -
* and therefore the types of the arguments to routines such as
* "gzseek()", as declared, with prototypes, in "zlib.h" - depends
* on whether HAVE_UNISTD_H is defined prior to including "zlib.h"!
*
* It's not defined in the FreeBSD 3.2 "zlib", so if we include "zlib.h"
* after defining HAVE_UNISTD_H, we get a misdeclaration of "gzseek()",
* and, if we're building with "zlib" support, anything that seeks
* on a file may not work.
*
* Other BSDs may have the same problem, if they haven't done something
* such as defining HAVE_UNISTD_H in "zconf.h".
*
* "config.h" defines HAVE_UNISTD_H, on all systems that have it, and all
* 4.4-Lite-derived BSDs have it. Therefore, given that "zlib.h" is included
* by "file_wrappers.h", that means that unless we include "zlib.h" before
* we include "config.h", we get a misdeclaration of "gzseek()".
*
* Unfortunately, it's "config.h" that tells us whether we have "zlib"
* in the first place, so we don't know whether to include "zlib.h"
* until we include "config.h"....
*
* A similar problem appears to occur with "gztell()", at least on
* NetBSD.
*
* To add further complication, on recent versions, at least, of OpenBSD,
* the Makefile for zlib defines HAVE_UNISTD_H.
*
* So what we do is, on all OSes other than OpenBSD, *undefine* HAVE_UNISTD_H
* before including "wtap.h" (we need "wtap.h" to get the WTAP_ERR_ZLIB
* values, and it also includes "zlib.h" if HAVE_ZLIB" is defined), and,
* if we have zlib, make "file_seek()" and "file_tell()" subroutines, so
* that the only calls to "gzseek()" and "gztell()" are in this file, which,
* by dint of the hackery described above, manages to correctly declare
* "gzseek()" and "gztell()".
*
* On OpenBSD, we forcibly *define* HAVE_UNISTD_H if it's not defined.
*
* Hopefully, the BSDs will, over time, remove the test for HAVE_UNISTD_H
* from "zconf.h", so that "gzseek()" and "gztell()" will be declared
* with the correct signature regardless of whether HAVE_UNISTD_H is
* defined, so that if they change the signature we don't have to worry
* about making sure it's defined or not defined.
*
* DO NOT, UNDER ANY CIRCUMSTANCES, REMOVE THE FOLLOWING LINES, OR MOVE
* THEM AFTER THE INCLUDE OF "wtap.h"! Doing so will cause any program
* using Wiretap to read capture files to fail miserably on a FreeBSD
* 3.2 or 3.3 system - and possibly some other BSD systems - if zlib is
* installed. If you *must* include <unistd.h> here, do so *before*
* including "wtap.h", and before undefining HAVE_UNISTD_H. If you
* *must* have HAVE_UNISTD_H defined before including "wtap.h", put
* "file_error()" into a file by itself, which can cheerfully include
* "wtap.h" and get "gzseek()" misdeclared, and include just "zlib.h"
* in this file - *after* undefining HAVE_UNISTD_H.
*/
#ifdef __OpenBSD__
#ifndef HAVE_UNISTD_H
#define HAVE_UNISTD_H
#endif /* HAVE_UNISTD_H */
#else /* __OpenBSD__ */
#undef HAVE_UNISTD_H
#endif /* __OpenBSD__ */
#include <errno.h>
#include <stdio.h>
#include "wtap-int.h"
#include "file_wrappers.h"
#ifdef HAVE_LIBZ
long
file_seek(void *stream, long offset, int whence, int *err)
{
long ret;
ret = gzseek(stream, (z_off_t)offset, whence);
if (ret == -1) {
/*
* XXX - "gzseek()", as of zlib 1.1.4, doesn't set
* "z_err" for the stream, so "gzerror()" could return
* a bogus Z_OK.
*
* As this call failed, we know "gzerror()" shouldn't
* return Z_OK; if it does, we assume that "errno" is
* the real error.
*/
*err = file_error(stream);
if (*err == 0)
*err = errno;
}
return ret;
}
long
file_tell(void *stream)
{
return (long)gztell(stream);
}
#else /* HAVE_LIBZ */
long
file_seek(void *stream, long offset, int whence, int *err)
{
long ret;
ret = fseek(stream, offset, whence);
if (ret == -1)
*err = file_error(stream);
return ret;
}
#endif /* HAVE_LIBZ */
/*
* Routine to return a Wiretap error code (0 for no error, an errno
* for a file error, or a WTAP_ERR_ code for other errors) for an
* I/O stream.
*/
#ifdef HAVE_LIBZ
int
file_error(void *fh)
{
int errnum;
gzerror(fh, &errnum);
switch (errnum) {
case Z_OK: /* no error */
return 0;
case Z_STREAM_END: /* EOF - not an error */
return 0;
case Z_ERRNO: /* file I/O error */
return errno;
default:
return WTAP_ERR_ZLIB + errnum;
}
}
#else /* HAVE_LIBZ */
int
file_error(FILE *fh)
{
if (ferror(fh))
return errno;
else
return 0;
}
#endif /* HAVE_LIBZ */
|
