17456c2e09
Update the big comment to reflect current reality. svn path=/trunk/; revision=16453
241 lines
6.7 KiB
C
241 lines
6.7 KiB
C
/* file_wrappers.c
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*
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* $Id$
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*
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* Wiretap Library
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* Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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/*
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* Do this now, to get close() defined, before we muck with the definition
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* of HAVE_UNISTD_H. See below for the full sad story of why we do that.
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*/
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif /* HAVE_UNISTD_H */
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/*
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* OK, now this is tricky.
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*
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* At least on FreeBSD 3.2, "/usr/include/zlib.h" includes
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* "/usr/include/zconf.h", which, if HAVE_UNISTD_H is defined,
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* #defines "z_off_t" to be "off_t", and if HAVE_UNISTD_H is
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* not defined, #defines "z_off_t" to be "long" if it's not
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* already #defined.
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*
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* In 4.4-Lite-derived systems such as FreeBSD, "off_t" is
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* "long long int", not "long int", so the definition of "z_off_t" -
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* and therefore the types of the arguments to routines such as
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* "gzseek()", as declared, with prototypes, in "zlib.h" - depends
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* on whether HAVE_UNISTD_H is defined prior to including "zlib.h"!
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*
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* It's not defined in the FreeBSD 3.2 "zlib", so if we include "zlib.h"
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* after defining HAVE_UNISTD_H, we get a misdeclaration of "gzseek()",
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* and, if we're building with "zlib" support, anything that seeks
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* on a file may not work.
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*
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* Other BSDs may have the same problem, if they haven't done something
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* such as defining HAVE_UNISTD_H in "zconf.h".
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*
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* "config.h" defines HAVE_UNISTD_H, on all systems that have it, and all
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* 4.4-Lite-derived BSDs have it. Therefore, given that "zlib.h" is included
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* by "file_wrappers.h", that means that unless we include "zlib.h" before
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* we include "config.h", we get a misdeclaration of "gzseek()".
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*
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* Unfortunately, it's "config.h" that tells us whether we have "zlib"
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* in the first place, so we don't know whether to include "zlib.h"
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* until we include "config.h"....
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*
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* A similar problem appears to occur with "gztell()", at least on
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* NetBSD.
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*
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* To add further complication, on recent versions, at least, of OpenBSD,
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* the Makefile for zlib defines HAVE_UNISTD_H.
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*
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* So what we do is, on all OSes other than OpenBSD, *undefine* HAVE_UNISTD_H
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* before including "wtap-int.h" (it handles including "zlib.h" if HAVE_ZLIB
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* is defined, and it includes "wtap.h", which we include to get the
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* WTAP_ERR_ZLIB values), and, if we have zlib, make "file_seek()" and
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* "file_tell()" subroutines, so that the only calls to "gzseek()" and
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* "gztell()" are in this file, which, by dint of the hackery described
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* above, manages to correctly declare "gzseek()" and "gztell()".
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*
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* On OpenBSD, we forcibly *define* HAVE_UNISTD_H if it's not defined.
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*
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* Hopefully, the BSDs will, over time, remove the test for HAVE_UNISTD_H
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* from "zconf.h", so that "gzseek()" and "gztell()" will be declared
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* with the correct signature regardless of whether HAVE_UNISTD_H is
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* defined, so that if they change the signature we don't have to worry
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* about making sure it's defined or not defined.
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*
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* DO NOT, UNDER ANY CIRCUMSTANCES, REMOVE THE FOLLOWING LINES, OR MOVE
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* THEM AFTER THE INCLUDE OF "wtap-int.h"! Doing so will cause any program
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* using Wiretap to read capture files to fail miserably on a FreeBSD
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* 3.2 or 3.3 system - and possibly some other BSD systems - if zlib is
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* installed. If you *must* have HAVE_UNISTD_H defined before including
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* "wtap-int.h", put "file_error()" into a file by itself, which can
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* cheerfully include "wtap.h" and get "gzseek()" misdeclared, and include
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* just "zlib.h" in this file - *after* undefining HAVE_UNISTD_H.
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*/
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#ifdef __OpenBSD__
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#ifndef HAVE_UNISTD_H
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#define HAVE_UNISTD_H
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#endif /* HAVE_UNISTD_H */
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#else /* __OpenBSD__ */
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#undef HAVE_UNISTD_H
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#endif /* __OpenBSD__ */
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#include <errno.h>
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#include <stdio.h>
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#ifdef HAVE_LIBZ
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#ifdef HAVE_FCNTL_H
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#include <fcntl.h>
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#endif /* HAVE_FCNTL_H */
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#include <string.h>
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#endif /* HAVE_LIBZ */
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#include "wtap-int.h"
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#include "file_wrappers.h"
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#include "file_util.h"
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#ifdef HAVE_LIBZ
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FILE_T
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file_open(const char *path, const char *mode)
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{
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int fd;
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FILE_T ft;
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int oflag;
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if (*mode == 'r') {
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if (strchr(mode + 1, '+') != NULL)
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oflag = O_RDWR;
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else
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oflag = O_RDONLY;
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} else if (*mode == 'w') {
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if (strchr(mode + 1, '+') != NULL)
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oflag = O_RDWR|O_CREAT|O_TRUNC;
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else
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oflag = O_RDONLY|O_CREAT|O_TRUNC;
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} else if (*mode == 'a') {
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if (strchr(mode + 1, '+') != NULL)
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oflag = O_RDWR|O_APPEND;
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else
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oflag = O_RDONLY|O_APPEND;
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} else {
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errno = EINVAL;
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return NULL;
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}
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#ifdef _WIN32
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if (strchr(mode + 1, 'b') != NULL)
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oflag |= O_BINARY;
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#endif
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/* open file and do correct filename conversions */
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if ((fd = eth_open(path, oflag, 0666)) == -1)
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return NULL;
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/* open zlib file handle */
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ft = gzdopen(fd, mode);
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if (ft == NULL) {
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eth_close(fd);
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return NULL;
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}
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return ft;
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}
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long
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file_seek(void *stream, long offset, int whence, int *err)
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{
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long ret;
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ret = gzseek(stream, (z_off_t)offset, whence);
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if (ret == -1) {
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/*
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* XXX - "gzseek()", as of zlib 1.1.4, doesn't set
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* "z_err" for the stream, so "gzerror()" could return
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* a bogus Z_OK.
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*
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* As this call failed, we know "gzerror()" shouldn't
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* return Z_OK; if it does, we assume that "errno" is
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* the real error.
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*/
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*err = file_error(stream);
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if (*err == 0)
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*err = errno;
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}
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return ret;
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}
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long
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file_tell(void *stream)
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{
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return (long)gztell(stream);
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}
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#else /* HAVE_LIBZ */
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long
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file_seek(void *stream, long offset, int whence, int *err)
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{
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long ret;
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ret = fseek(stream, offset, whence);
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if (ret == -1)
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*err = file_error(stream);
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return ret;
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}
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#endif /* HAVE_LIBZ */
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/*
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* Routine to return a Wiretap error code (0 for no error, an errno
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* for a file error, or a WTAP_ERR_ code for other errors) for an
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* I/O stream.
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*/
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#ifdef HAVE_LIBZ
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int
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file_error(void *fh)
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{
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int errnum;
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gzerror(fh, &errnum);
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switch (errnum) {
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case Z_OK: /* no error */
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return 0;
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case Z_STREAM_END: /* EOF - not an error */
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return 0;
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case Z_ERRNO: /* file I/O error */
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return errno;
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default:
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return WTAP_ERR_ZLIB + errnum;
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}
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}
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#else /* HAVE_LIBZ */
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int
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file_error(FILE *fh)
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{
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if (ferror(fh))
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return errno;
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else
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return 0;
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}
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#endif /* HAVE_LIBZ */
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