From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Sun, 18 Nov 2012 18:48:49 +0100
Subject: [Buildroot] [PATCH] busybox: needs linux-pam dependency added
 if using custom busybox .config & busybox login applet
In-Reply-To: <50A91D44.5060104@petroprogram.com>
References: <1353197713-20796-1-git-send-email-stefan.froberg@petroprogram.com>
 <20121118174000.0fe79ef6@skate> <50A91D44.5060104@petroprogram.com>
Message-ID: <20121118184849.660aad23@skate>
List-Id: <buildroot.busybox.net>
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To: buildroot@busybox.net

Dear Stefan Fr?berg,

On Sun, 18 Nov 2012 19:39:16 +0200, Stefan Fr?berg wrote:

> And that CONFIG_LOGIN checking should be done after buybox tarball has
> been extracted but by then, it is already too late for
> determining dependencies ....
> Aarrggggh!

I think you understood what the problem is :)

> > It is really difficult to have dependencies that are needed only when
> > some specific Busybox features are enabled.
> Tell me about it.
> What IMHO is needed, is some function or way to get these kinds of
> information.
> Just before dependencies are determined.
> 
> There should be KCONFIG_GET_OPT or something similar inside
> package/pkg-utils.mk
> (like there already is KCONFIG_ENABLE_OPT, KCONFIG_DISABLE_OPT and
> KCONFIG_SET_OPT)
> that would help to determine not only buildroot features but also linux
> features and any
> else package that use kconfig like stuff.
> 
> It would also help in case of  various package conflicts (say if busybox
> unzip applet and real unzip are mistakenly
> being installed, then this could be detected beforehand)

KCONFIG_GET_OPT cannot work: you could only call it in a Makefile rule
(i.e inside BUILD_CMDS or CONFIGURE_CMDS or a hook or something like
that). But by the time those are executed, it is way too late to
declare a dependency. The dependencies (in BUSYBOX_DEPENDENCIES) must
be detailed when make parses all the .mk files, not when the rules are
executed.

Unless I'm wrong, linux-pam is only needed if ENABLE_PAM is defined
when building Busybox, correct? So, CONFIG_LOGIN builds just fine
without PAM, doesn't it?

So maybe you should rather do:

ifeq ($(BR2_PACKAGE_LINUX_PAM),y)
BUSYBOX_DEPENDENCIES += linux-pam
BUSYBOX_CFLAGS += -DENABLE_PAM
endif

No?

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com