[PATCH v2 3/4] image-commands: support Chromium OS image-type creation

[Paul Spooren]

On So, Jan 17, 2021 at 09:20, Brian Norris 
<computersforpeace at gmail.com> wrote:
> Hi Paul,
> 
> On Sun, Jan 17, 2021 at 2:43 AM Paul Spooren <mail at aparcar.org> wrote:
>>  On Sat Jan 16, 2021 at 5:07 PM HST, Brian Norris wrote:
>>  > See the previous patches, which implemented the cros-vbutil
>>  > verified-boot payload-packing tool, and extended ptgen for the 
>> CrOS
>>  > kernel partition type. With these, it's now possible to package 
>> kernel +
>>  > rootfs to make disk images that can boot a Chrome OS-based system 
>> (e.g.,
>>  > Chromebooks, or even a few AP models).
>>  >
>>  > gen_image_vboot.sh borrows a bit of structure from 
>> gen_image_generic.sh,
>>  > but I didn't feel it fit well to try and add new flags to the 
>> latter,
>>  > given the difference in its FAT kernel packaging and our raw 
>> kernel
>>  > partition packing.
>>  >
>>  > Signed-off-by: Brian Norris <computersforpeace at gmail.com>
>>  > ---
>>  > include/image-commands.mk | 18 ++++++++++
>>  > .../base-files/files/lib/upgrade/common.sh | 4 ++-
>>  > scripts/gen_image_vboot.sh | 36 +++++++++++++++++++
>>  > 3 files changed, 57 insertions(+), 1 deletion(-)
>>  > create mode 100755 scripts/gen_image_vboot.sh
>>  >
>>  > diff --git a/include/image-commands.mk b/include/image-commands.mk
>>  > index 979eafb15734..f02d8e79fce6 100644
>>  > --- a/include/image-commands.mk
>>  > +++ b/include/image-commands.mk
>>  > @@ -172,6 +172,24 @@ define Build/fit
>>  > @mv $@.new $@
>>  > endef
>>  >
>>  > +define Build/cros-image
>>  > + $(SCRIPT_DIR)/gen_image_vboot.sh \
>>  > + $@ \
>>  > + $(CONFIG_TARGET_KERNEL_PARTSIZE) \
>> 
>>  You're passing the kernel size twice here which the script expects
>>  <size> <image>. Am I missing something?
> 
> From the error/help text:
> 
>     echo "SYNTAX: $0 <file> <bootpart size> <kernel size> <kernel
> image> <rootfs size> <rootfs image>"
> 
> It's a bit awkward, but for the first partition, it's only asking for
> a <size>. I haven't fully fleshed it out yet, but this first partition
> is a spare FAT partition, for use in sysupgrade. I believe other
> systems reuse the kernel partition (which tends to be either FAT or
> ext4), but because Chrome OS systems use a signed blob (and not a
> proper filesystem) for their kernel partitions, I needed to create an
> extra partition, with no special data in it.
> 
> Also, I don't really have a separate Kconfig option for defining the
> FAT partition size -- I just reused the kernel partition size.
> 
> I'm open to suggestions on this, but the current code is written as
> intended. I'm not very familiar with OpenWRT image-construction best
> practices (e.g., adding more Kconfig parameters?).

Sorry for the confusion, within a git rebase the file wasn't updated 
and lacked that parameter, causing error message on execution. It works 
fine now.

I have no idea for a better name, if you suspect other devices could 
use this functionality as well that use other sizes we should design it 
more flexible.

> Thanks,
> Brian