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Re: gnutls error handling
From: |
Eli Zaretskii |
Subject: |
Re: gnutls error handling |
Date: |
Sun, 17 Oct 2010 11:22:22 -0400 |
> 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).