kernel space logging

[chambilkethakur@gmail.com (Anuz Pratap Singh Tomar)]

On Fri, Mar 25, 2011 at 5:43 PM, Anand Arumugam <anand.arumug@gmail.com>wrote:

> On Thu, Mar 24, 2011 at 5:47 PM, Greg Freemyer <greg.freemyer@gmail.com>
> wrote:
> > On Tue, Mar 22, 2011 at 1:13 PM, Anand Arumugam <anand.arumug@gmail.com>
> wrote:
> >> Hello all!
> >>
> >> I would like to know how logging is done while the kernel is booting
> >> up. More importantly I am looking for those files in the kernel source
> >> that handles the logging part. Also I would like to know what gets
> >> logged after the kernel is up and running.
> >>
> >> Thanks for your time.
> >>
> >> cheers,
> >> -anand.
> >
> > Are you talking about the logs you see when you run dmesg?
> >
> > You are aware the kernel maintains a ring buffer that all printk's go
> into.
> >
> > Then there are API's that let userspace track the buffer and put the
> > messages into on disk logs.
> >
> > dmesg just dumps out the ring buffer queue.
> >
> > The userspace API to the ring buffer is syslog().
> >
> > So during bootup I _assume_ the kernel is just logging to the ring
> > buffer, and then when the system is operational enough, userspace gets
> > all the boot messages out of the kernel via syslog() and puts them to
> > on disk log files.
> >
> > It's not too magic.
> >
> > Greg
> >
>
> I was looking for the logging framework used by the kernel developers.
> Not just the dmesg logs.
>
>
hope this helps:
http://www.ibm.com/developerworks/linux/library/l-kernel-logging-apis/?ca=drs-

this is a tool and good read otherwise:

http://www.cs.huji.ac.il/~etsman/klogger/
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