Re: gnutls error handling

[Eli Zaretskii]

> From: Lars Magne Ingebrigtsen <address@hidden>
> Date: Sun, 17 Oct 2010 15:55:24 +0200
> Mail-Copies-To: never
> 
> poll([{fd=4, events=POLLIN}, {fd=3, events=POLLIN}], 2, 0) = 0 (Timeout)
> select(15, [3 4 8 10 13], [], NULL, {0, 15591}) = 2 (in [8 10], left {0, 
> 15589})
> read(3, 0xec9b94, 4096)                 = -1 EAGAIN (Resource temporarily 
> unavailable)
> poll([{fd=4, events=POLLIN}, {fd=3, events=POLLIN}], 2, 0) = 0 (Timeout)
> select(15, [3 4 8 10 13], [], NULL, {0, 15532}) = 2 (in [8 10], left {0, 
> 15530})
> read(3, 0xec9b94, 4096)                 = -1 EAGAIN (Resource temporarily 
> unavailable)
> 
> There's always a gnutls socket involved in the select call -- in this
> instance it was fd 10.  lsof showed the socket to be in the CLOSE_WAIT
> state.  So my suspicion is that the we're somehow now communicating back
> to Emacs that a gnutls socket has closed.

Not really a useful answer, but the `select' man page has this piece
of wisdom:

       Under Linux, select() may report a socket file descriptor as
       "ready for reading", while nevertheless a subsequent read
       blocks.  This could for example happen when data has arrived
       but upon examination has wrong checksum and is discarded.
       There may be other circumstances in which a file descriptor is
       spuriously reported as ready.  Thus it may be safer to use
       O_NONBLOCK on sockets that should not block.

Of course, we already use O_NONBLOCK (AFAIK).