On Mon, Sep 14, 2009 at 1:22 PM, Leonidas . <leonidas...@gmail.com> wrote:
> > > Hi List > > I have written a kernel module which implements a char device. An userspace > app > is supposed to get data from my module and then dump it into a file for > further processing. > > The kind of data which kernel module is going to pass to userspace is going > to be a 4K buffer, > and the data traffic is not going to be really heavy, meaning may be a 4K > buffer every 1 min or so. > I am not very sure though, but certainly not heavy traffic the way they > describe for network traffic etc. > > And this data needs to be logged to a file either from kernel or userspace > and an userspace all will work > on that data. This data needs to be logged as soon as it arrives meaning, I > might not be able to write it to > /proc since from module I can update /proc only when user actually accesses > it. This data needs to be > static in nature, meaning I get one error and I write it to a file somehow > and user can see it anytime. > > I hope I have described the situation clearly. I have explored some > mechanism like ioctls, mmaping the > kernel buffer etc but all these would require the user module to poll or > notified somehow by kernel that > the data is available. I dont want the user module to poll. > > > -Leo. > > When we do a printk it writes to kernel log buffer, correct? This is real in time operation i.e. as soon as we do a printk the messages get logged. Now this log file can be accesses from /var/log/messages right? How is this done? I want to so something similar, so I can log my messages to a seprate file which is going to stay around so user can see at across reboots as well. -Leo.
