[Discuss-gnuradio] Run to Completion with gr-ieee80211

[Paul Garver]

I’ve derived a flow graph, playback_wifi_rx_cli.grc [1] from the wifi_rx example given in gr-ieee80211 [2] which is a CLI version taking a sc16-formatted sample file and outputs a .pcap file for wireshark. The goal is to  use this CLI program for batch data processing in my research. Unfortunately, I am having an issue with “run to completion”. The program executes, processes all the data, but never exits.  I’ve followed the debugging steps given in [3]. Output is below:

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.007.003-0-ge10df19c

Using Volk machine: avx_64_mmx

( … launching lots of threads … )

^Z
Program received signal SIGTSTP, Stopped (user).
0x00007ffff78e8c33 in select () at ../sysdeps/unix/syscall-template.S:81
81 ../sysdeps/unix/syscall-template.S: No such file or directory.
(gdb) info threads
  Id   Target Id         Frame 
  23   Thread 0x7fff83fff700 (LWP 18714) "python" pthread_cond_wait@@GLIBC_2.3.2 ()
    at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
  22   Thread 0x7fffa4ff9700 (LWP 18713) "file_sink16" pthread_cond_timedwait@@GLIBC_2.3.2 ()
    at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:238
  21   Thread 0x7fffa57fa700 (LWP 18712) "wireshark_conn1" pthread_cond_wait@@GLIBC_2.3.2 ()
    at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
* 1    Thread 0x7ffff7fd5740 (LWP 18689) "python" 0x00007ffff78e8c33 in select ()
    at ../sysdeps/unix/syscall-template.S:81

It appears the wireshark block is the cause of the hangup. Looking into the source code [4], there is a provision for an EOF object "is_eof_object()”.  Which block sends this object? I enabled debugging and the wireshark block never receives it. It seems like maybe the file source should send it at the EOF of the file. If y’all could explain how the object is sent and perhaps point me in the right direction for additional debugging that would be most helpful.  Thanks!

PWG

[1] https://github.com/garverp/gr-ieee802-11/blob/offline_processing/examples/playback_wifi_rx_cli.grc

[2] https://github.com/bastibl/gr-ieee802-11

[3] https://lists.gnu.org/archive/html/discuss-gnuradio/2015-04/msg00002.html

[4] https://github.com/bastibl/gr-foo/blob/master/lib/wireshark_connector_impl.cc