[v3] Makefile: drop ldconfig handling

The ldconfig handling in the main Makefile is utterly broken, as it
calls the build machine ldconfig to generate the ld.so.cache of the
target. Unfortunately, the format of the ld.so.cache is architecture
specific, and therefore the build machine ldconfig cannot be used
as-is.

This patch therefore simply drops using ldconfig entirely, and removes
/etc/ld.so.conf.d/ from the target skeleton. The idea is that all
libraries that should be loaded by the dynamic linker must be
installed in paths where the dynamic linker searches them by default
(typically /lib or /usr/lib).

This might potentially break a few packages, but the only way to know
is to actually stop handling ldconfig.

In order to be notified of such cases, we add a check in
target-finalize to verify that there is no /etc/ld.so.conf file as
well as no /etc/ld.so.conf.d directory.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
Changes from v2:
 - Move back the checks *before* the rootfs overlay and post-build
   scripts are applied. As indicated by Yann, this potentially leaves
   the possibility for a user to use ld.so configuration in its
   overlay/post-build script, as long as (s)he also takes care of the
   ldconfig mess.

Changes from v1:
 - Add check for /etc/ld.so.conf.d suggested by Yann
 - Move the checks after copying the rootfs overlays and running the
   post build scripts, in order to catch cases where the ld.so
   configuration would be added by an overlay or a post-build
   script. This was suggested by Arnout.
---
 Makefile                                | 17 ++++-------------
 system/skeleton/etc/ld.so.conf.d/.empty |  0
 2 files changed, 4 insertions(+), 13 deletions(-)
 delete mode 100644 system/skeleton/etc/ld.so.conf.d/.empty

diff --git a/system/skeleton/etc/ld.so.conf.d/.empty b/system/skeleton/etc/ld.so.conf.d/.empty
deleted file mode 100644
index e69de29..0000000

Thomas, All,

On 2016-01-01 22:23 +0100, Thomas Petazzoni spake thusly:
> The ldconfig handling in the main Makefile is utterly broken, as it
> calls the build machine ldconfig to generate the ld.so.cache of the
> target. Unfortunately, the format of the ld.so.cache is architecture
> specific, and therefore the build machine ldconfig cannot be used
> as-is.
> 
> This patch therefore simply drops using ldconfig entirely, and removes
> /etc/ld.so.conf.d/ from the target skeleton. The idea is that all
> libraries that should be loaded by the dynamic linker must be
> installed in paths where the dynamic linker searches them by default
> (typically /lib or /usr/lib).
> 
> This might potentially break a few packages, but the only way to know
> is to actually stop handling ldconfig.
> 
> In order to be notified of such cases, we add a check in
> target-finalize to verify that there is no /etc/ld.so.conf file as
> well as no /etc/ld.so.conf.d directory.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> ---
> Changes from v2:
>  - Move back the checks *before* the rootfs overlay and post-build
>    scripts are applied. As indicated by Yann, this potentially leaves
>    the possibility for a user to use ld.so configuration in its
>    overlay/post-build script, as long as (s)he also takes care of the
>    ldconfig mess.
> 
> Changes from v1:
>  - Add check for /etc/ld.so.conf.d suggested by Yann
>  - Move the checks after copying the rootfs overlays and running the
>    post build scripts, in order to catch cases where the ld.so
>    configuration would be added by an overlay or a post-build
>    script. This was suggested by Arnout.
> ---
>  Makefile                                | 17 ++++-------------
>  system/skeleton/etc/ld.so.conf.d/.empty |  0
>  2 files changed, 4 insertions(+), 13 deletions(-)
>  delete mode 100644 system/skeleton/etc/ld.so.conf.d/.empty
> 
> diff --git a/Makefile b/Makefile
> index 80e94a2..0883175 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -604,20 +604,11 @@ endif
>  # debugging symbols.
>  	find $(TARGET_DIR)/lib -type f -name 'ld-*.so*' | \
>  		xargs -r $(STRIPCMD) $(STRIP_STRIP_DEBUG)
> -
> +	test -f $(TARGET_DIR)/etc/ld.so.conf && \
> +		{ echo "ERROR: we shouldn't have a /etc/ld.so.conf file"; exit 1; } || true
> +	test -d $(TARGET_DIR)/etc/ld.so.conf.d && \
> +		{ echo "ERROR: we shouldn't have a /etc/ld.so.conf.d directory"; exit 1; } || true
>  	mkdir -p $(TARGET_DIR)/etc
> -	# Mandatory configuration file and auxiliary cache directory
> -	# for recent versions of ldconfig
> -	touch $(TARGET_DIR)/etc/ld.so.conf
> -	mkdir -p $(TARGET_DIR)/var/cache/ldconfig
> -	if [ -x "$(TARGET_CROSS)ldconfig" ]; \
> -	then \
> -		$(TARGET_CROSS)ldconfig -r $(TARGET_DIR) \
> -					-f $(TARGET_DIR)/etc/ld.so.conf; \
> -	else \
> -		/sbin/ldconfig -r $(TARGET_DIR) \
> -			       -f $(TARGET_DIR)/etc/ld.so.conf; \
> -	fi
>  	( \
>  		echo "NAME=Buildroot"; \
>  		echo "VERSION=$(BR2_VERSION_FULL)"; \
> diff --git a/system/skeleton/etc/ld.so.conf.d/.empty b/system/skeleton/etc/ld.so.conf.d/.empty
> deleted file mode 100644
> index e69de29..0000000
> -- 
> 2.6.4
>

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

 > The ldconfig handling in the main Makefile is utterly broken, as it
 > calls the build machine ldconfig to generate the ld.so.cache of the
 > target. Unfortunately, the format of the ld.so.cache is architecture
 > specific, and therefore the build machine ldconfig cannot be used
 > as-is.

 > This patch therefore simply drops using ldconfig entirely, and removes
 > /etc/ld.so.conf.d/ from the target skeleton. The idea is that all
 > libraries that should be loaded by the dynamic linker must be
 > installed in paths where the dynamic linker searches them by default
 > (typically /lib or /usr/lib).

 > This might potentially break a few packages, but the only way to know
 > is to actually stop handling ldconfig.

 > In order to be notified of such cases, we add a check in
 > target-finalize to verify that there is no /etc/ld.so.conf file as
 > well as no /etc/ld.so.conf.d directory.

 > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Committed, thanks.