Open new shell terminal to allow command entry without crashing main app
 

Hi All,

I am relatively new to linux (know enough to be dangerous!) and new to this forum.

What I am trying to do is open an interactive shell terminal so that process information can be obtained.

Currently, the software we are running contains debug/monitoring software. What I would like to do is exit out of the debug into a new shell terminal and enter commands such as cat/proc/meminfo without interrupting the main app that is running. I then would exit the shell with exit or control-d.

I have tried 'system("/bin/sh -i");' in the appropriate software file to get an interactive terminal. This opens up a new terminal, but unfortunately as soon as I press any key, the main app crashes and the following is received: [1]+ Stopped (SIGVTALRM) run.

I'm not sure what else I need to do to get this to work.

I hope this makes some sort of sense.

Any help and advice would be greatly appreciated.

Many thanks in advance.

Why don't you just have the program itself execute the "cat /proc/meminfo"?

WARNING: Speculation follows:
It sounds like you are calling "system" in the same thread context as the "debug/monitoring" software, which may cause a timeout to expire and issue the SIGVTALARM. You might have better success making your call to "system" from another thread.

However, without a better understanding of how "the software we are running" and the "debug/monitoring software" interact, I am not sure I can help you. Do the two parts of the software run in the same execution thread? Maybe you could provide a little diagram or verbal description of the overall software architecture.

Can you just log on to a virtual terminal and issue whatever commands you need? To get a VT login, just hit Shift-Alt-F1 and log in. To get back to your main app, assuming it is running in a GUI, hit Alt-F7.

Most distros have 6 VT's, accessed by Shift-Alt-F(n) where n = the VT # (1-6). VT 7 is usually your GUI session, but you can also bring up VT 8, VT 9, etc. with the switch user feature, usually accessed via the logout menu.

Turns out the problem was thread related.

Thanks to all who replied because it was these replies that enabled me to solve the problem.