[PLUG] Slapper.C

Paul Heinlein heinlein at attbi.com
Tue Oct 1 21:54:55 UTC 2002


On Tue, 1 Oct 2002, Keith Nasman wrote:

> > b) that you restarted all ssl-enabled services (web, mail,
> >    whatever) after you updated to the latest openssl rpm
> > 
> That I did not. I guess that is a standard procedure that I didn't
> know about. Does that mean that these other services keep a running
> copy for themselves, rather than hitting the (updated) library each
> time? Enlighten me on this :-)

A competent C programmer could give you a more complete explanation...

What seems to happen is that when a process (e.g., httpd) is started, 
the linker maps into memory any dynamic libraries against which the 
process is linked (e.g., libssl.so) and then does magic so that the 
main process can find the library's routines in memory.

Once started, the process typically doesn't have anything to do with
the disk-based copy of itself or the libraries against which it's
linked.

So you can delete a program or its libraries out from underneath 
itself without affecting the running process.

The only way to pick up new, patched libraries it to restart the 
process.

--Paul Heinlein <heinlein at attbi.com>





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