From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <c0ac78fdc42afa4540b05a4f87ef83cd@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Fri, 25 Jul 2008 07:47:32 -0400
To: steve@quintile.net, 9fans@9fans.net
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Subject: Re: [9fans] kernel, errfmt
Topicbox-Message-UUID: f02c82de-ead3-11e9-9d60-3106f5b1d025

> I have become confused trying to understand
> the kernel's linkage.
>
> the kernel uses print() in many places, e.g.
> /sys/src/9/port/xalloc.c:80
>
> /sys/src/9/port/devcons.c:211 This calls vseprint().
>
> /sys/src/libc/fmt/fmt.c:47 The fmt library installs %r
> (errfmt) by default.
>
> /sys/src/libc/fmt/errfmt.c:10 references rerrstr().
>
> /sys/src/libc/9sys/rerrstr.c:10 references errstr().
>
> Errstr() is a system call and does not exist in the
> kernel (where it becomes syserrstr()).
>
> How can this work? ...or does the kernel itself
> perform system calls?

i believe /sys/src/libc/9syscall generates entry points.
there are text symbols in libc.a for the symbols you
mention.

however, using %r might be a problem.  the kernel
should likely have a stub

int
errfmt(Fmt *f)
{
	return fmtstrcpy(f, up->errstr);
}

- erik