On Fri, Mar 25, 2011 at 1:43 PM, Anand Arumugam <anand.arumug@xxxxxxxxx> wrote: > On Thu, Mar 24, 2011 at 5:47 PM, Greg Freemyer <greg.freemyer@xxxxxxxxx> wrote: >> On Tue, Mar 22, 2011 at 1:13 PM, Anand Arumugam <anand.arumug@xxxxxxxxx> 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. > Most of its in kernel/printk.c and include/linux/printk.h If you mean the API for the framework, it is most easily seen in the .h file: http://lxr.linux.no/#linux+v2.6.38/include/linux/printk.h For the guts, see vprintk in particular: http://lxr.linux.no/#linux+v2.6.38/kernel/printk.c#L729 HTH Greg _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
