In these days I was thinking on a way to implement concurrent startup.
I wrote a daemon that may receive requests through TCP. I called it
"bogoserver" because now it's simple and bogus, but it may become a very
powerful daemon.
/ect/init.d/rc can launch startup scripts with "startup $i start &", so
scripts are executed concurrently; but startup() must be modified and
should ask to bogoserver if the script dependencies are satisfied. After
the script is executed, startup() must notify this to bogoserver.
To do this, startup() must execute a function that gets the dependencies
of this script. Dependencies may be obtained parsing the script as
defined on LSB, but I think the function may also read dependencies from
a config file, so we don't need to edit every script and we may override
easily the dependencies.
Then startup() can send a message to bogoserver for each dependency.
Unfortunately, Debian's bash doesn't supports TCP, so we must use netcat
and execute "echo wait wantedService | nc localhost $BOGOSERVER_PORT".
This will lock this istance of startup() until bogoserver returns a
message and closes the socket. This may happen immediately, or after the
execution of wantedService.
After the execution of the script, startup() must do "echo started $1 |
nc localhost $BOGOSERVER_PORT", so bogoserver can unlock other istances
of startup and the boot can go on.
This is the new startup():
startup() {
#getDependencies not yet implemented
DEPENDS=$(getDependencies $1);
for i in $DEPENDS; do
echo "wait $i" | nc localhost $BOGOSERVER_PORT
done
case "$1" in
*.sh)
$debug sh "$@"
;;
*)
$debug "$@"
;;
esac
echo started $1 | nc localhost $BOGOSERVER_PORT
fi
}
You can download the source of bogoserver from
http://bootster.berlios.de/bogoserver/bogoserver-0.0.1.c
I think it may be improved in some way, for example it uses a linked
lists to keep track of services. However, the number of startup services
is generally low, and structure with lower computational complexity may
have lower performances!
Then bogoserver doesn't handle yet change of runlevel or shutdown, but
just boot. This is just the first version, you can help me and improve it!
Please ask if I was not clear, and send some feedback!
Regards
Fabio
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