Lamar Owen <lamar.owen@wgcr.org> writes:
> How does netstat find out?
netstat burrows around in kernel datastructures, is how.
I don't see invoking netstat as a solution anyway. For one thing,
it's drastically nonstandard; even if available, it varies in parameters
and output format (your "simple example" draws a usage complaint on my
box). Furthermore, a moderately security-conscious admin would probably
choose to make netstat unavailable to unprivileged users, since it
reveals an uncomfortably large amount about the activity of other users.
A final complaint is that netstat would actually reveal *too much*
information, since a netstat-based client would have no way to choose
among multiple postmasters. (Please recall that one of the motivations
for the UUNET patch was to allow multiple postmasters running with the
same port number in different subdirectories. Hmm, I wonder how netstat
shows socketfiles that are in chroot'd subtrees, or outside your own
chroot ...)
regards, tom lane