PORTING to IBM OS/390: select() always returning 0 in entropy.c

[mouring at etoh.eviladmin.org]

On Fri, 5 Jan 2001, Paul Anderson wrote:

> Hello,
>     I'm attempting to port OpenSSH to IBM's S/390 mainframe. Things
>have gone well but I have come a little unstuck with the internal
>PRNG. Although the commands in ssh_prng_cmds are being executed the
>select() seems to be returning 0 and therefore the cose is assuming that
>the forked process has timed out. This could be a difference in the way

If select() returns 0 it means that the select() timed out.  Look at your
ssh_prng_cmds and consider increasing the number on the left handside by
very small amounts until you hit the magical number that allows you get to
get enough entropy.

And I suggest you hound IBM to put in a /dev/urandom.

that select is implemented on OS/390. The Unix environment provided by OS/390 has many compatability levels from including several POSIX and XPG variants. I am not a C expert and the debugegr is not very good, has anyone come across smiliar behavior before. A description of the select() on OS/390 can be found at: http://www.s390.ibm.com/bookmgr-cgi/bookmgr.cmd/BOOKS/EDCLB031/4%2e1%2e131?SHELF=CBCBS031
> 
> Thanks, Paul Anderson
>