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From: Sascha Retzki <sretzki@gmx.de>
Subject: Help on /srv, named pipes
Date: Fri, 22 Sep 2006 16:30:23 +0200


Hi,

I am playing arround with irc7, a multichannel irc-client. There is irc, which uses /srv (a named pipe to ircsrv) for outgoing things (commands to be send to the irc-server), but a file in /tmp to recieve data from the irc-server. (One (may) use irc to just read/write to one target/victim (irc channel or person), so I just open two-three win(1)s in acme and start ircs' for each channel I want to be in).

I don't like the incoming data to be in /tmp, for example it behaves like a logfile, it spams my harddisk, etc. Most importantly, I did not get why there is a named pipe waiting for clients in /srv, but a file in /tmp is used.

So I changed irc7/irc.c to read/write all traffic via /srv/glendairc and made ircsrv.c write to /srv/glendairc instead of /tmp/whatnot. Piece of cake.


Reading pipe(3):
If there are multiple writers, each write is guaranteed to
be available in a contiguous piece at the other end of the
pipe.  If there are multiple readers, each read will return
data from only one write.

I read 'from only one write' as 'multiple "clients" may open and use /srv/glendairc, they all will get all data (ordered)' - however that is not the case. Depending on which one of the clients is currently reading (or so it seems), it is the only recipient. I have got a question at this point: Did I misget that concept? Is that intentioned behaviour (why?)?
(In case it matters, libbio is used to recieve the data from /tmp^W/srv/glendairc )



I put the current source-code at sources:
9fs sources
/n/sources/contrib/sascharetzki/src/irc7.2-srv-only.tgz 


In case I do get all the concepts right, and I just did not write correct code, I will go and read my code again. Examples (greping for /srv in /sys/src/cmd/*.c isn't that much fun after all ;-/ )?


Thanks for your time,


Sascha