[Winpcap-users] Offline capture opening path with spaces (Windows)

Guy Harris guy at alum.mit.edu
Sat Jun 30 16:09:46 PDT 2012

On May 4, 2012, at 12:36 AM, Stefan Billeb wrote:

> I am developing with jNetPcap on Java which is (most of you will know) a wrapper for winpcap.
> When I try to open an offline capture pcap file and the path to the file contains whitespaces an exception is thrown and it cannot get opened.

It works with libpcap:

	$ tcpdump -n -r ~/captures/hpteaming/"teaming heartbeat.pcap"
	reading from file /Users/gharris/captures/hpteaming/teaming heartbeat.pcap, link-type EN10MB (Ethernet)
	13:24:00.137165 LLDP, length 93: PROCURVE J9029A
	13:24:30.266764 LLDP, length 93: PROCURVE J9029A
	13:25:00.397212 LLDP, length 93: PROCURVE J9029A


and should Just Work with WinPcap as well - a space is not a particular special character in file names in any UN*X or Windows APIs (it might be a special character on the *command line* for UN*X or Windows, but that's a separate matter).

Perhaps either

	1) Java is doing something silly with spaces in strings;

	2) jNetPcap is doing something silly with spaces in strings;

	3) something *else* is causing the problem.

What type of exception is being thrown?

Do you mean that in

> // code snippet
> final StringBuilder errbuf = new StringBuilder();
>        Pcap pcap = Pcap.openOffline(filename, errbuf);
>        if(pcap == null) {
>            System.err.printf("Error while opening device for capture: "
>                    + errbuf.toString());
>            return false;
>        }

an exception is thrown in Pcap.openOffline and it never even gets to the "if(pcap == null)" test?

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