[Buildroot] [PATCH v2 1/1] package/avahi: add optional support for libcap

[Buildroot] [PATCH v2 1/1] package/avahi: add optional support for libcap

[Bernd Kuhls]

When libcap was compiled before, avahi daemon will use it as optional
dependency:

$ output/host/usr/bin/x86_64-linux-readelf -a output/target/usr/sbin/avahi-daemon | grep NEEDED | sort
 0x0000000000000001 (NEEDED)             Shared library: [libavahi-common.so.3]
 0x0000000000000001 (NEEDED)             Shared library: [libavahi-core.so.7]
 0x0000000000000001 (NEEDED)             Shared library: [libcap.so.2]
[...]

The build system offers no option to en-/disable libcap support:
http://git.0pointer.net/avahi.git/tree/configure.ac#n382

The check for libcap was placed inside the BR2_PACKAGE_AVAHI_DAEMON
because only avahi-daemon uses libcap, it provides chroot support.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
---
v2: moved the new code block a bit and added more notes about the usage
    of libcap (Thomas)

 package/avahi/avahi.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/package/avahi/avahi.mk b/package/avahi/avahi.mk
index 5d6e6a8..e84a69e 100644
--- a/package/avahi/avahi.mk
+++ b/package/avahi/avahi.mk
@@ -118,6 +118,9 @@ endif
 ifeq ($(BR2_PACKAGE_AVAHI_DAEMON),y)
 AVAHI_DEPENDENCIES += expat
 AVAHI_CONF_OPTS += --with-xml=expat
+ifeq ($(BR2_PACKAGE_LIBCAP),y)
+AVAHI_DEPENDENCIES += libcap
+endif
 else
 AVAHI_CONF_OPTS += --with-xml=none
 endif
-- 
2.7.0

[Buildroot] [PATCH v2 1/1] package/avahi: add optional support for libcap

[Thomas Petazzoni]

Dear Bernd Kuhls,

On Sun, 21 Feb 2016 18:57:19 +0100, Bernd Kuhls wrote:
> When libcap was compiled before, avahi daemon will use it as optional
> dependency:
> 
> $ output/host/usr/bin/x86_64-linux-readelf -a output/target/usr/sbin/avahi-daemon | grep NEEDED | sort
>  0x0000000000000001 (NEEDED)             Shared library: [libavahi-common.so.3]
>  0x0000000000000001 (NEEDED)             Shared library: [libavahi-core.so.7]
>  0x0000000000000001 (NEEDED)             Shared library: [libcap.so.2]
> [...]
> 
> The build system offers no option to en-/disable libcap support:
> http://git.0pointer.net/avahi.git/tree/configure.ac#n382
> 
> The check for libcap was placed inside the BR2_PACKAGE_AVAHI_DAEMON
> because only avahi-daemon uses libcap, it provides chroot support.

Still, the configure.ac test is done unconditionally (i.e regardless
of whether the daemon is enabled or not), so I believe we should also
do the same.

Peter, Yann, Arnout, your thoughts?

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[Buildroot] [PATCH v2 1/1] package/avahi: add optional support for libcap

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

 > Dear Bernd Kuhls,
 > On Sun, 21 Feb 2016 18:57:19 +0100, Bernd Kuhls wrote:
 >> When libcap was compiled before, avahi daemon will use it as optional
 >> dependency:
 >> 
 >> $ output/host/usr/bin/x86_64-linux-readelf -a output/target/usr/sbin/avahi-daemon | grep NEEDED | sort
 >> 0x0000000000000001 (NEEDED)             Shared library: [libavahi-common.so.3]
 >> 0x0000000000000001 (NEEDED)             Shared library: [libavahi-core.so.7]
 >> 0x0000000000000001 (NEEDED)             Shared library: [libcap.so.2]
 >> [...]
 >> 
 >> The build system offers no option to en-/disable libcap support:
 >> http://git.0pointer.net/avahi.git/tree/configure.ac#n382
 >> 
 >> The check for libcap was placed inside the BR2_PACKAGE_AVAHI_DAEMON
 >> because only avahi-daemon uses libcap, it provides chroot support.

 > Still, the configure.ac test is done unconditionally (i.e regardless
 > of whether the daemon is enabled or not), so I believe we should also
 > do the same.

 > Peter, Yann, Arnout, your thoughts?

It's safer to do it unconditionally (and we are unlikely to have
problems with dependency loops with avahi/libcap, so that's not an issue
either).

So I would prefer to have it outside the _DAEMON conditional as well.

-- 
Venlig hilsen,
Peter Korsgaard 

[Buildroot] [PATCH v2 1/1] package/avahi: add optional support for libcap

[Yann E. MORIN]

Bernd, Thomas, Peter, All,

On 2016-02-21 21:43 +0100, Peter Korsgaard spake thusly:
> >>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:
> 
>  > Dear Bernd Kuhls,
>  > On Sun, 21 Feb 2016 18:57:19 +0100, Bernd Kuhls wrote:
>  >> When libcap was compiled before, avahi daemon will use it as optional
>  >> dependency:
>  >> 
>  >> $ output/host/usr/bin/x86_64-linux-readelf -a output/target/usr/sbin/avahi-daemon | grep NEEDED | sort
>  >> 0x0000000000000001 (NEEDED)             Shared library: [libavahi-common.so.3]
>  >> 0x0000000000000001 (NEEDED)             Shared library: [libavahi-core.so.7]
>  >> 0x0000000000000001 (NEEDED)             Shared library: [libcap.so.2]
>  >> [...]
>  >> 
>  >> The build system offers no option to en-/disable libcap support:
>  >> http://git.0pointer.net/avahi.git/tree/configure.ac#n382
>  >> 
>  >> The check for libcap was placed inside the BR2_PACKAGE_AVAHI_DAEMON
>  >> because only avahi-daemon uses libcap, it provides chroot support.
> 
>  > Still, the configure.ac test is done unconditionally (i.e regardless
>  > of whether the daemon is enabled or not), so I believe we should also
>  > do the same.
> 
>  > Peter, Yann, Arnout, your thoughts?
> 
> It's safer to do it unconditionally (and we are unlikely to have
> problems with dependency loops with avahi/libcap, so that's not an issue
> either).
> 
> So I would prefer to have it outside the _DAEMON conditional as well.

Yes, agreed.

With a comment explaining so, of course.

Regards,
Yann E. MORIN.

-- 
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[Buildroot] [PATCH v2 1/1] package/avahi: add optional support for libcap

[Thomas Petazzoni]

Bernd,

On Sun, 21 Feb 2016 18:57:19 +0100, Bernd Kuhls wrote:
> When libcap was compiled before, avahi daemon will use it as optional
> dependency:
> 
> $ output/host/usr/bin/x86_64-linux-readelf -a output/target/usr/sbin/avahi-daemon | grep NEEDED | sort
>  0x0000000000000001 (NEEDED)             Shared library: [libavahi-common.so.3]
>  0x0000000000000001 (NEEDED)             Shared library: [libavahi-core.so.7]
>  0x0000000000000001 (NEEDED)             Shared library: [libcap.so.2]
> [...]
> 
> The build system offers no option to en-/disable libcap support:
> http://git.0pointer.net/avahi.git/tree/configure.ac#n382
> 
> The check for libcap was placed inside the BR2_PACKAGE_AVAHI_DAEMON
> because only avahi-daemon uses libcap, it provides chroot support.
> 
> Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
> ---
> v2: moved the new code block a bit and added more notes about the usage
>     of libcap (Thomas)

I've changed the patch to have the libcap condition outside of the
avahi daemon condition, as discussed during the review, and applied to
master.

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com