On Sat, 01 May 2010 20:16:46 +0200, foo bar wrote:
You know, it's nice to know the name of people sending code to us.
Anonymous code is unlikely to go anywhere.
> On 05/01/2010 06:42 PM, Jean Delvare wrote:
> > Hi,
> >
> > On Sat, 01 May 2010 17:29:04 +0200, PyroPeter wrote:
> >
> >> Some months ago, the /etc/fancontrol syntax changed,
> >>
> > Please be specific. The syntax never changed, it was extended in
> > fully backwards compatible ways, this should never have caused
> > fancontrol to fail, unless you downgraded it.
> >
> >
> At the 28th of February I had to add DEVPATH and DEVNAME settings to my
> config file.
Oh, yeah, that change. Indeed, it was not backwards compatible, my bad.
The irony is that these entries were added to prevent fancontrol from
failing in some cases, but in the end it made fancontrol fail in even
more cases. Oh well.
> Of cause this is my fault, because I manually wrote the config.
Not your fault, a pwmconfig-generated file would have gone out of date
just the same.
> >> and fancontrol
> >> exited right after startup, but the init script stated success.
> >>
> >> Currently there is no reliable way for a init script to check if
> >> fancontrol started up properly.
> >>
> > Running it using startproc should do the trick. That's what openSUSE
> > does.
>
> After reading the manpage online, I get the impression that startproc
> just has the advantage of checking for an already running daemon before
> starting it. But I will take a look at a SUSE initscript.
Well...
# startproc /bin/true
# echo $?
7
#
So apparently it can find out whether the child process exited
> Besides that, I do not get how you should check if fancontrol started up
> properly.
It seems startproc does it for you. So you just get to check for the
result of startproc.
> The only way I could imagine is: you run fancontrol, wait some seconds
> and then check for the pid-file. I won't have to tell anyone how dirty
> that is.
Hopefully you won't have to do that.
> >> As fancontrol is a deamon preventing hardware damage, reliability should
> >> be of first priority.
> >>
> > This is incorrect. fancontrol is a daemon _causing_ hardware damage, if
> > anything. The initial state of your system should be safe, so
> > fancontrol not starting should never be a safety issue.
> >
> >
> Not for me. My mainboard has some kind of broken fan control that always
> sets a very low speed, which makes it acoustically indistinguishable
> from fancontrol but fails at high CPU loads. But that is not a
> fancontrol issue at the first point.
Your mainboard or BIOS is broken, and/or you should select a different
thermal profile in the BIOS setup screen. You should simply never rely
on fancontrol to keep your system healthy. fancontrol is there to make
your system silent, nothing else.
> >> I would suggest adding a argument to fancontrol that makes it start up,
> >> check config syntax and write permissions, and than fork to the
> >> background, or return a positive exit code.
> >>
> >>
> >> I wrote a kind of proof of concept that simply uses the existing
> >> bash-script and "forks" by reexecuting itself in the background:
> >>
> >> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> >> diff -ru lm_sensors-3.1.2-1/usr/sbin/fancontrol
> >> lm_sensors-3.1.2-1_pyropeter/usr/sbin/fancontrol
> >> --- lm_sensors-3.1.2-1/usr/sbin/fancontrol 2010-02-03
> >> 03:45:15.000000000 +0100
> >> +++ lm_sensors-3.1.2-1_pyropeter/usr/sbin/fancontrol 2010-03-07
> >> 01:37:09.000000000 +0100
> >> @@ -5,7 +5,9 @@
> >> #
> >> # Version 0.70
> >> #
> >> -# Usage: fancontrol [CONFIGFILE]
> >> +# Usage: fancontrol [-D] [CONFIGFILE]
> >> +#
> >> +# (-D causes fancontrol to 'fork' to the background after some tests)
> >> #
> >> # Dependencies:
> >> # bash, egrep, sed, cut, sleep, readlink, lm_sensors :)
> >> @@ -43,6 +45,12 @@
> >> #DEBUG=1
> >> MAX=255
> >>
> >> +DAEMON=0
> >> +if [ "$1" = "-D" ]; then
> >> + DAEMON=1
> >> + shift
> >> +fi
> >> +
> >> declare -i pwmval
> >>
> >> function LoadConfig {
> >> @@ -303,7 +311,6 @@
> >> echo "File $PIDFILE exists, is fancontrol already running?"
> >> exit 1
> >> fi
> >> -echo $$> "$PIDFILE"
> >>
> >> # $1 = pwm file name
> >> function pwmdisable()
> >> @@ -475,6 +482,14 @@
> >> let fcvcount=$fcvcount+1
> >> done
> >>
> >> +if [ "$DAEMON" -gt 0 ]; then
> >> + echo "Forking..."
> >> + $0 $*&> /dev/null&
> >> + exit 0
> >> +fi
> >> +
> >> +echo $$> "$PIDFILE"
> >> +
> >> echo 'Starting automatic fan control...'
> >>
> >> # main loop calling the main function at specified intervals
> >>
> >> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> >> I am not subscribed to this mailing list, so you need to CC me.
> >>
> >>
> > This means that the checks will be done twice.
> There could be a second argument that skips the tests. But I don't think
> parsing a 400B file two time is going to harm.
Sure. But then everybody says that for everything that starts when the
machine boots, and we end up with sluggish systems.
> > And if the checks are
> > somehow incomplete, fancontrol may still fail despite the fork being
> > successful, so it is unreliable by design.
>
> What do you mean by "somehow incomplete"?
I used a vague term on purpose.
> I can't imagine a case where the old behavior is more reliable than the
> one I supposed, unless there are bugs in the implementation.
And there are bugs in the implementation, believe me...
> (Btw. I just noticed the fork itself could break in some cases, so it
> needs an additional if-clause :-P)
--
Jean Delvare
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