Re: Debugging an issue with pcap_compile/pcap_setfilter

[Adayadil Thomas <adayadil.thomas () gmail com>]

I tried after compiling with -ll and that does not solve the problem.

1. Is pcap_setfilter and pcap_compile threadsafe?
  My program runs couple of threads and each makes a call to
pcap_setfilter and pcap_compile.

2. Running under valgrind gave this

a. reports that there is no symbol table for libpcap
b. an error about uninitialized bytes in setsockopt call

Is this relevant?

--3794-- Reading syms from /usr/lib/libpcap.so.0.9.4 (0x400F000)
--3794--    object doesn't have a symbol table
--3794-- Reading syms from /lib/libpthread-2.5.so (0x4DECC000)

==3794== Thread 3:
==3794== Syscall param socketcall.setsockopt(optval) points to
uninitialised byte(s)
==3794==    at 0x4DDF05D7: setsockopt (in /lib/libc-2.5.so)
==3794==    by 0x4014C68: pcap_setfilter (in /usr/lib/libpcap.so.0.9.4)
==3794==    by 0x804C207: PacketFunc (program.c:1069)
==3794==    by 0x4DED149A: start_thread (in /lib/libpthread-2.5.so)
==3794==    by 0x4DDEF42D: clone (in /lib/libc-2.5.so)
==3794==  Address 0x683B232 is on thread 3's stack


Please advice,

Thanks


On Fri, Oct 30, 2009 at 2:34 PM, Adayadil Thomas
<adayadil.thomas () gmail com> wrote:
> I did not use the -ll option. I can try with that.
>
> However, the problem cannot be easily replicated. I see the issue only rarely.
> I don't know if that makes sense.
>
> With the same filter "tcp[13]&7!=0" I can run the program many times
> and not see the issue.
> And once in a while I see the issue.
>
> If it is related to the -ll the problem should be seen every time, right?
>
>
>
> On Fri, Oct 30, 2009 at 3:21 PM, Guy Harris <guy () alum mit edu> wrote:
> > On Oct 29, 2009, at 8:23 AM, Adayadil Thomas wrote:
> >
> > > symbol lookup error: /usr/lib/libpcap.so.0.9.4: undefined symbol:
> > > lex_cleanup
> >
> > When you built your program, did you link it with the "-ll" option?
> >
> > If not, try rebuilding it, and linking with "-ll", and let us know whether
> > that fixes the problem.
> > -
> > This is the tcpdump-workers list.
> > Visit https://cod.sandelman.ca/ to unsubscribe.
-
This is the tcpdump-workers list.
Visit https://cod.sandelman.ca/ to unsubscribe.