On Sat, 26 Jun 2010, Mulyadi Santosa wrote: > Hi... > > On Sat, Jun 26, 2010 at 03:53, Chris <chris.maier85@xxxxxx> wrote: > > I read the pages 83-90 in the LDD3 and the sources > > (http://lxr.linux.no/#linux+v2.6.34/include/linux/proc_fs.h). > > > > Now, I am a little confused. The struct proc_dir_entry contains a > > struct file_operations. Thus I can implement all standard file > > operations on a proc file entry? > > AFAIK, only read and write (if it is meant to be writeable). Note: > these days you need to use sequential write and read. refer to Rob > PJ Day's articles on how to do such thing. Rob, please, go ahead on > this... not only read and write -- you can certainly also implement lseek. , at the very least. and even though it's getting a bit dated, /proc files are covered fairly well in LDD3, which is available online at http://lwn.net/Kernel/LDD3/. see chapter 4. also, you don't *need* to use the seq_file implementation, that's just a newer way to use proc files that gets around an old length limitation on how much you could print from a single proc file. but there are still lots of examples of the older interface in the kernel the last time i looked. read that chapter in LDD3, it explains it fairly well. and here's where i become a bit conflicted. ironically (and i'm trying very hard not to be self-serving again), i just happen to be writing the section on proc files for my online kernel programming course so while i'm happy to still answer basic questions here, i feel like i have to limit myself to not reproducing everything i'm going to put in that section, since that would be unfair to the registered students who've paid for the course. argh. i hate conflicts of interest. but read LDD3, it's a very good coverage of proc files. rday -- ======================================================================== Robert P. J. Day Waterloo, Ontario, CANADA Top-notch, inexpensive online Linux/OSS/kernel courses http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ======================================================================== -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
