[Buildroot] [PATCH v2] Makefile: drop ldconfig handling

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2015-12-31 15:48 +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. Such checks are done after the
> rootfs overlays are copied and post-build scripts are executed, in
> order to also catch the cases where such mechanisms would add ld.so
> related configuration.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
> 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.

I disagree on that one.

We basically tell user that they can do "whatever they want" in a
post-build-script. So, if a user has a mean to create the ld.so.cache,
we should not prevent him to do so.

For example, a user may have a first-install procedure on his machine,
that runs ldocnfig natively on the machine. Custom (aka br2-external
packages may install libraries in weird locations (proprietary stuff)
and can not change that (because other proprietary binary-only stuff).
In this vase a "first-install" procedure may run ldconfig natively on
the target, and that would be OK.

Or he may have a cross-ldconfig (from wherever that comes) so he could
run that in a post-build script.

So I believe this check should be before the overlay and post-build
scripts.

Regards,
Yann E. MORIN.

> ---
>  Makefile                                | 17 +++++------------
>  system/skeleton/etc/ld.so.conf.d/.empty |  0
>  2 files changed, 5 insertions(+), 12 deletions(-)
>  delete mode 100644 system/skeleton/etc/ld.so.conf.d/.empty
> 
> diff --git a/Makefile b/Makefile
> index 1d69192..8953b02 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -598,18 +598,6 @@ endif
>  		xargs -r $(STRIPCMD) $(STRIP_STRIP_DEBUG)
>  
>  	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)"; \
> @@ -628,6 +616,11 @@ endif
>  		$(call MESSAGE,"Executing post-build script $(s)"); \
>  		$(EXTRA_ENV) $(s) $(TARGET_DIR) $(call qstrip,$(BR2_ROOTFS_POST_SCRIPT_ARGS))$(sep))
>  
> +	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
> +
>  target-post-image: $(TARGETS_ROOTFS) target-finalize
>  	@$(foreach s, $(call qstrip,$(BR2_ROOTFS_POST_IMAGE_SCRIPT)), \
>  		$(call MESSAGE,"Executing post-image script $(s)"); \
> 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
> 

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