[Buildroot] [PATCH v1 2/2] dhcp: disable isc assertions (reproducible builds)

[Thomas Petazzoni]

Hello,

On Fri, 27 Oct 2017 21:24:24 +0200, Peter Seiderer wrote:
> The isc assertions from the bundled bind dns library are
> using the __FILE__ macro for debug messages (see
> dhcp-4.3.5/bind/bind-9.9.9-P3/lib/isc/include/isc/assertions.h).
> 
> Disabling the assertions gains:
> 
> - reproducible builds (no built time pathes in the executable)
> - space saving on the target:
>   dhcpd: 1.9M -> 1.6M
>   dhcrelay: 1.6M -> 1.3M
> 
> Signed-off-by: Peter Seiderer <ps.report at gmx.net>
> ---
>  package/dhcp/dhcp.mk | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/package/dhcp/dhcp.mk b/package/dhcp/dhcp.mk
> index 45cae087aa..0bae61283a 100644
> --- a/package/dhcp/dhcp.mk
> +++ b/package/dhcp/dhcp.mk
> @@ -11,7 +11,9 @@ DHCP_LICENSE = ISC
>  DHCP_LICENSE_FILES = LICENSE
>  DHCP_CONF_ENV = \
>  	CPPFLAGS='-D_PATH_DHCPD_CONF=\"/etc/dhcp/dhcpd.conf\" \
> -		-D_PATH_DHCLIENT_CONF=\"/etc/dhcp/dhclient.conf\"'
> +		-D_PATH_DHCLIENT_CONF=\"/etc/dhcp/dhclient.conf\"' \
> +	CFLAGS='$(TARGET_CFLAGS) -DISC_CHECK_NONE=1'

I'm not sure about this one.

Do we want to remove assertions from production code ?

Regarding the __FILE__ problem, I think this is going to bite us on a
large number of packages. So instead of a per-package solution, we
should perhaps have a look at:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70268, proposal for a
  -ffile-map-prefix option to gcc

  https://wiki.debian.org/ReproducibleBuilds/BuildPathProposal, also
  discussing a similar idea

Peter, Arnout, Yann, what do you think, especially about the
assertions ?

Best regards,

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