Subject: summoning a daemon

From: mulix <[email-masked]>
Date: Tue, 28 Nov 2000 01:11:36 +0200 (EET)

hi,

in january i will give to haifux (haifa's linux club) a lecture on writing
daemons.

i'd like the lecture to be based upon my experiences writing a daemon.
the lecture will detail the design process and the implementation issues
specific to a daemon.

unfortunately, i don't have a good idea for a daemon. so, what is that
little background utility you always wanted and never found on freshmeat?
what will make a "cool" (for any definition of "cool") daemon? any ideas
will be welcome.

haifux members will thank you, too, since a good idea will spare them the
joys of listening about the
free-disk-space-watching-sould've-been-a-cron-job daemon i will default
to...

thanks in advance,
-- 
mulix

linux/reboot.h: #define LINUX_REBOOT_MAGIC1 0xfee1dead

---

From: Adi Stav <[email-masked]>
Date: Tue, 28 Nov 2000 10:07:27 +0200

> free-disk-space-watching-sould've-been-a-cron-job daemon i will default

Ooh, great topic... Two ideas that have been floating around:

A FIFO superserver. Like inetd, but attempts to open a lot of FIFOs
instead and runs programs for them. It can be used for signatures like
Chen pointed out, but it's a more general solution and probably has
other applications. (/etc/passwd for older programs and
whatnots). This way you are not required to run a separate daemon for
every FIFO. Possible problems: multiple readers might mangle the
readings. And maybe open() will block in an un-select()able way, I
didn't check. Maybe UNIX-domain sockets will be more appropriate -- I
didn't check.

Inetd that also lets users register listeners on, crond-style. This
way users who want to run their own servers don't have to have an
active daemon.