Function for finding Which process is using a port

raghu2383 · 10-12-2008, 09:44 PM

Hi,

I am trying to find a C library routine/ sys call that would enable me to find which process is using a particular port. For example, lets sasy I want to find out which process(es) is using port# 2000 to send and receive messasges.
I searched online and found that there is a function called lsof that returns values to the shell when called. But how could I do it in a C program, without having to call lsof and write its results into a file, and then scanning it. I am utilizing a TCP connection on ubuntu with gcc 4.2.3

Thanks in advance.

paulsm4 · 10-12-2008, 11:18 PM

Hi -

There is no such function in C (or any other language).

The short answer is:
"On Linux, 'lsof' uses '/proc'".

But for the full story, why don't you simply look at the lsof source itself? It's freely available, and very informative. Here's one place you can get it:

http://freshmeat.net/projects/lsof/

'Hope that helps .. PSM