Date: Mon, 31 Dec 2001 10:59:40 +0200 From: Peter Pentchev <roam@ringlet.net> To: Mike Barcroft <mike@freebsd.org> Cc: Mike Smith <msmith@freebsd.org>, hackers@freebsd.org Subject: Re: loadable aio Message-ID: <20011231105940.B3512@straylight.oblivion.bg> In-Reply-To: <20011231034807.D45114@espresso.q9media.com>; from mike@freebsd.org on Mon, Dec 31, 2001 at 03:48:07AM -0500 References: <20011230215630.B45114@espresso.q9media.com> <200112310508.fBV58MI03596@mass.dis.org> <20011231034807.D45114@espresso.q9media.com>
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On Mon, Dec 31, 2001 at 03:48:07AM -0500, Mike Barcroft wrote:
> Mike Smith <msmith@freebsd.org> writes:
> > > Terry Lambert <tlambert2@mindspring.com> writes:
> > > > There is so much "goo" around the module loading these days; there
> > > > are incursions into "mount" and all sorts of other programs that
> > > > should not know about module loading.
> > >
> > > The kldload(2) interface alone is enough to make me cringe. The way
> > > in which it locates a module to load appears to be black magic.
> >
> > What part of searching a path for a matching file is "black magic"?
> >
> > Shells have been doing this for decades...
>
> %%%
> /*
> * Load /boot/kernel/procfs.ko
> * XXX: why does this work?
> */
> chdir("/");
> kldload("procfs");
>
> /*
> * Load /boot/kernel/procfs.ko
> * XXX: why does this work?
> */
> chdir("/");
> kldload("procfs.ko");
>
> /*
> * Load /boot/kernel/procfs.ko
> */
> kldload("/boot/kernel/procfs.ko"); /* Proper interface */
>
> /*
> * Move procfs.ko from /boot/kernel to /tmp, then load the copy in /tmp.
> */
> system("/bin/mv /boot/kernel/procfs.ko /tmp");
> chdir("/tmp");
> kldload("procfs.ko"); /* XXX: this doesn't work. */
> %%%
>
> If that's not black magic, I'd like to know what is. I'd like to
> refer you to the kldload(2) manual, but unfortunately it doesn't
> document how kldload(2) works. :(
Okay, so it's not documented in the manual, but one look at the source
should suffice :)
As Mike said, there is a search path. However, the current directory
is tried first. If a file by that name is not found in the current
directory, the search path is, well, searched ;) The search path
is available in the kern.module_path sysctl or in the output of
'kldconfig -r'.
This is similar to what shells have been doing for decades, with
the added feature of an implicit '.' at the start of the search path.
G'luck,
Peter
--
Do you think anybody has ever had *precisely this thought* before?
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