[Valgrind-developers] fdleak_ipv4 doesn't work on Darwin

[Nicholas N. <n.n...@gm...>]

Hi,

none/tests/fdleak_ipv4 doesn't work on Darwin.  I can't work out why,
but I don't know much about network programming.  If anyone who does
(Filipe?) it would be very helpful.

The program forks and creates a client process and a server process.
If the server process runs first and reaches accept() before the
client tries to connect(), it works fine.  I tested this by inserting
a sleep() in the client.

But without that sleep(), on my machine usually the client reaches
connect() first.  It fails with "connection refused", which is
reasonable, because the server hasn't started listening/accepting
connections.  But then on the retry, after the sleep(1), the connect()
fails with an invalid argument.  And this repeats 10 times around the
client's connect() loop until the client gives up.

It's the invalid argument errors that I don't understand.  I looked at
the xnu kernel sources, AFAICT the only way to get EINVAL from
connect() is to make the 3rd arg (address_len) too small but that's
definitely not the case.  Besides, if we don't get EINVAL on the first
try, why should we get it on subsequent tries with identical
arguments?

Finally, the server process never shuts down, it just hangs waiting
for accept(), which complicates subsequent runs.

Any ideas?  I attach a version which prints messages before and after
each network operation, which makes it easier to debug.

Nick