kernel space logging

[Anand Arumugam]

On Fri, Mar 25, 2011 at 1:50 PM, Anuz Pratap Singh Tomar
<chambilkethakur at gmail.com> wrote:
>
>
> On Fri, Mar 25, 2011 at 5:43 PM, Anand Arumugam <anand.arumug at gmail.com>
> wrote:
>>
>> On Thu, Mar 24, 2011 at 5:47 PM, Greg Freemyer <greg.freemyer at gmail.com>
>> wrote:
>> > On Tue, Mar 22, 2011 at 1:13 PM, Anand Arumugam <anand.arumug at 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/
>

@Greg-Freemyer and @Anuz: Thank you so much for the references and
clarifications.

cheers...