kernel newb -- read/write to a local file from in kernel
Poul-Henning Kamp
phk at phk.freebsd.dk
Sun Sep 4 23:46:13 PDT 2005
In message <431BE951.4070101 at c4solutions.net>, Jeb Campbell writes:
>I'm trying to learn about kernel programming and as a weekend project
>I've started writing a Netgraph to file/dev module.
>
>The Netgraph stuff was pretty easy, but I'm at a loss on the file access
>part as I've never done anything in-kernel.
>
>After much searching (most of it not knowing what I was looking for), I
>think that I'm looking for something like "Vnode interface mechanics,
>write to a local file" as taught in Mr. McKusick's "FreeBSD Kernel
>Internals: An Intensive Code Walkthrough".
>
>I've looked at nullfs/null_vnops.c, but I think that is more of a
>pass-through example. Does anyone know of any online code that shows
>the process of opening a file/device for read/write?
In the spirit of education I won't tell you "how to" but only "where
to look": ktrace, coredumps and accounting all writes to files
from the kernel.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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