Main Menu

KB#00317-When a telnet session is killed or a modem line is dropped, a running BBx application will not exit properly

Title:

When a telnet session is killed or a modem line is dropped, a running BBx application will not exit properly

Description:

When the communications layer underneath a UNIX BBx process is suddenly terminated, it's possible for the BBx process to continue running in a defunct state. This is generally characterized by the process no longer being associated with a tty device while still using up CPU time. Both of these can be verified by a 'ps' command under UNIX. 

The BBx process can be put in this state under the following circumstances: 
1) When the Windows telnet session is killed 
2) When the carrier is dropped if the telnet session is running over a modem

Resolution:

This problem occurs when the shell that BBx is running under is instructed to ignore a SIGHUP. Some shells, such as the korn and bourne shell, allow you to cause the shell and any applications running in it to ignore a hang up signal. This is set via the trap command, and will usually look something like: 

trap "" 1 

in a shell startup file. The 1 indicates that the shell and its applications should ignore a hang up signal, which is what BBx receives when the telnet session is terminated abnormally. 

To solve the problem, modify or remove the trap statement. When this is done, the shell and BBx will always see a SIGHUP signal and BBx will be able to recover gracefully from a terminated connection.



Last Modified: 03/31/1998 Product: PRO/5 Operating System: Unix

BASIS structures five components of their technology into the BBx Generations.

  Google+ View BASIS LinkedIN Profile Visit our Twitter Feed Check out our Facebook Public Profile Click to View the BASIS youTube channel