From owner-freebsd-hackers@FreeBSD.ORG  Tue May 15 06:47:44 2007
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From: Marc =?iso-8859-1?q?L=F6rner?= <marc.loerner@hob.de>
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Date: Tue, 15 May 2007 07:47:38 +0100
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Cc: Lawrence Stewart <lstewart@room52.net>
Subject: Re: Writing a plain text file to disk from kernel space
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Hello Lawrence,

in file kern/vfs_syscalls.c you can see the kern_open function that uses 
vn_open to open a file/vnode.

There are more vn_* functions like vn_rdwr for reading and writing to a vnode 
or vn_close to close a vnode. To see how theses functions work, I suggest you 
grep for them in the kernel-files.

BTW, you can get an thread-struct pointer from curthread (c.f. sys/pcpu.h).

HTH,
Marc Lörner