From owner-freebsd-hackers@FreeBSD.ORG  Wed Aug  8 17:42:47 2007
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Date: Wed, 8 Aug 2007 12:25:36 -0500
From: Craig Boston <cb@severious.net>
To: Biks N <freebsd.dev@gmail.com>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: Using userland library in Kernel
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On Wed, Aug 08, 2007 at 11:23:25AM -0500, Biks N wrote:
> I am new to FreeBSD kernel programming and I am trying to use userland
> library (zlib) in FreeBSD kernel. But I am not sure if zlib library is
> linkable from the kernel.

Normally, no, you can't just link in a library designed for userland
into the kernel.  Some porting is required to deal with the kernel
environment -- things such as not having a full C library available,
different memory management, etc.

In this case however, there is already a zlib implementation in the
kernel.  IIRC, geom_uzip and the crypto framework both use it.

You may want to check out sys/net/zlib.[ch] and see if it can do what
you're after.  You'll need to make sure to include a dependency on the
zlib module and/or add it to your kernel configuration.

Good luck,
Craig