[Buildroot] [PATCH v3 2/7] boot/grub2: add support to build multiple Grub2 configurations in the same build

[Yann E. MORIN]

Köry, All,

On 2021-10-07 14:43 +0200, Köry Maincent spake thusly:
> On Thu, 7 Oct 2021 11:53:26 +0200
> "Yann E. MORIN" <yann.morin.1998 at free.fr> wrote:
[--SNIP--]
> > By using --with-platform=none in the main CONF_OPTS, we should be able
> > to disable building any of the "images", and just build the tools.
> > 
> > Totally untested, of course...
> As I said if we do that we won't have all the Grub modules in the target
> directory. I think these modules are quiet important, an user that wants to use
> grub-mkimage will surely use them for example. 

OK, I had a hard time understanding what you meant... But indeed,
BR2_TARGET_GRUB2_INSTALL_TOOLS *also* wants to install the modules in
target/

In this case, this should not be too complex either; we just need a
post-image hook that copies all modules into TARGET_DIR, like:

    diff --git a/boot/grub2/grub2.mk b/boot/grub2/grub2.mk
    index e01ebb2edb..0bb10d765d 100644
    --- a/boot/grub2/grub2.mk
    +++ b/boot/grub2/grub2.mk
    @@ -50,11 +50,6 @@ GRUB2_IGNORE_CVES += CVE-2019-14865
     # version available in Buildroot.
     GRUB2_IGNORE_CVES += CVE-2020-15705
     
    -ifeq ($(BR2_TARGET_GRUB2_INSTALL_TOOLS),y)
    -GRUB2_INSTALL_TARGET = YES
    -else
    -GRUB2_INSTALL_TARGET = NO
    -endif
     GRUB2_CPE_ID_VENDOR = gnu
     
     GRUB2_BUILTIN_MODULES_PC = $(call qstrip,$(BR2_TARGET_GRUB2_BUILTIN_MODULES_PC))
    @@ -127,6 +122,9 @@ GRUB2_TUPLES-$(BR2_TARGET_GRUB2_ARM64_EFI) += arm64-efi
     HOST_GRUB2_CONF_ENV = \
         CPP="$(HOSTCC) -E"
     
    +# Main build: only build tools
    +GRUB2_CONF_OPTS = --with-platform=none --blabla...
    +
     GRUB2_CONF_ENV = \
         CPP="$(TARGET_CC) -E" \
         TARGET_CC="$(TARGET_CC)" \
    @@ -147,7 +145,7 @@ HOST_GRUB2_CONF_OPTS = \
         --enable-libzfs=no \
         --disable-werror
     
    -define GRUB2_CONFIGURE_CMDS
    +define GRUB2_CONFIGURE_CMDS_PTF
         $(foreach tuple, $(GRUB2_TUPLES-y), \
             mkdir -p $(@D)/build-$(tuple) ; \
             cd $(@D)/build-$(tuple) ; \
    @@ -169,14 +167,16 @@ define GRUB2_CONFIGURE_CMDS
                 --disable-werror
         )
     endef
    +GRUB2_POST_CONFIGURE_HOOKS += GRUB2_CONFIGURE_CMDS_PTF
     
    -define GRUB2_BUILD_CMDS
    +define GRUB2_BUILD_CMDS_PTF
         $(foreach tuple, $(GRUB2_TUPLES-y), \
             $(TARGET_MAKE_ENV) $(MAKE) -C $(@D)/build-$(tuple)
         )
     endef
    +GRUB2_POST_BUILD_HOOKS += GRUB2_BUILD_CMDS_PTF
     
    -define GRUB2_INSTALL_IMAGES_CMDS
    +define GRUB2_INSTALL_IMAGES_CMDS_PTF
         $(foreach tuple, $(GRUB2_TUPLES-y), \
             mkdir -p $(dir $(GRUB2_IMAGE_$(tuple))) ; \
             $(HOST_DIR)/usr/bin/grub-mkimage \
    @@ -194,6 +194,23 @@ define GRUB2_INSTALL_IMAGES_CMDS
             ) \
         )
     endef
    +GRUB2_POST_INSTALL_IMAGES_HOOKS += GRUB2_INSTALL_IMAGES_CMDS_PTF
     
    -$(eval $(generic-package))
    +ifeq ($(BR2_TARGET_GRUB2_INSTALL_TOOLS),y)
    +GRUB2_INSTALL_TARGET = YES
    +define GRUB2_INSTALL_MODS_IN_TARGET
    +    mkdir -p $(TARGET_DIR)/boot
    +    $(foreach tuple, $(GRUB2_TUPLES-y), \
    +        cp -a $(GRUB2_IMAGE_$(tuple)) $(TARGET_DIR)/boot/
    +    )
    +endef
    +# **YES** this is a post-install-image hook that installs in target/
    +# **AND** we need it to be registered **LAST**, after all the per-tuple
    +# image-install hooks
    +GRUB2_POST_INSTALL_IMAGES_HOOKS += GRUB2_INSTALL_MODS_IN_TARGET
    +else
    +GRUB2_INSTALL_TARGET = NO
    +endif
    +
    +$(eval $(autotools-package))
     $(eval $(host-autotools-package))


NOTE: yes, I know that $(GRUB2_IMAGE_$(tuple)) is not exactly what we
need to copy, and that it will need some additional tweaking.

But then, maybe installing all the per-tuple to target/ might just
work in the end. That would not be nice, but as Thomas already said,
grub2 is already not nice anyway...

Also, I just noticed that we copy the cdboot.img from the host dir! Are
the modules all there?

Regards,
Yann E. MORIN.

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