From mboxrd@z Thu Jan  1 00:00:00 1970
Message-Id: <200509211432.j8LEWEX00091@zamenhof.cs.utwente.nl>
To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
Subject: Re: [9fans] thread confusion
In-reply-to: Your message of "Wed, 21 Sep 2005 15:53:51 +0200."
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References: <6aec7d5cd5d9af853b090abafcff13a4@lsub.org> 
From: Axel Belinfante <Axel.Belinfante@cs.utwente.nl>
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Date: Wed, 21 Sep 2005 16:32:13 +0200
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> :  A/The main weird thing is that after doing threadint on a thread
> :  (created with proccreate) which presumably is hanging in a read
> :  sometimes(?) the process just disappears without leaving a trace,
> :  even though it is packed with syslog calls
> :  (of which only the first part gets executed).
> 
> Did you call threadnotify()?

No, threadint() (see below)

> Put a print there (the handler) to see what's going on.
lots of syslog already (instead of print - does that matter?)

> Also, forwarding advice Russ gave time before :-), read the alef paper
> and don't use interrupts at all.

Agreed. I tried to do that (not use interrupts).

The problem is that in this particular thread/proc I call
library routine tlsClient which may hang in a read from a pipe
of which I am holding the other end (to tunnel the messages).
It may happen that 'the other end' decides to give up
on a TLS handshake in progress and start a new TLS handshake,
in which case I have to 'clean up' my side of the handshake
in progress.
This is where sometimes things go wrong:
it seems that just closing my end of the pipe
is not sufficient to get tlsClient out of the read.

That's why I tried to resort to threadint:
	"Threadint interrupts a thread that is blocked
	 in a channel operation or system call"
(although now the question is what it means to be interrupted)

Probably I should instead investigate how/why closing
(my end of) the pipe is not sufficient.

Would not be surprised if I'm making mistake that's
so trivial/basic that I'm just overlooking it :-(

(in the mean time my piece of code/administration to
 deal with all this is starting to live a life of its
 own so just getting it right and simple would be good.
 back to the drawing board, I guess...)

Axel.