[Buildroot] bsdiff with buildroot

[Arnout Vandecappelle]

  Hi Santhosh,

On 04/14/16 07:30, Santhosh Ramani wrote:
> Hello,
>
> I'm trying to install bsdiff package and using buildroot to create my rootfs for
> AM335x device. I've selected the option of custom toolchain and using the
> toolchain provided by TI as part of their SDK 7.0.
>
> I'm having some trouble with bzip2, it's a pre-requisite for bsdiff. When
> installing bzip2, cp seemed to fail. I had to replace the cp statement.

  Since the problem is with bzip2, it would have been more appropriate to put 
that in the subject.

>
>
> Original statement
> =================
> *cp -f bzip2
> /home/sramani/buildroot/buildroot/output/host/usr/arm-buildroot-linux-gnueabihf/sysroot/usr/bin/bunzip2
> *
>
>
> Updated statement
> =================
> *cp --remove-destination -f ~/buildroot/buildroot/output/build/bzip2-1.0.6/bzip2
> /home/sramani/buildroot/buildroot/output/host/usr/arm-buildroot-linux-gnueabihf/sysroot/usr/bin/bunzip2*
>
> I had to do the same thing for *bunzip2*, and *bzcat*.

  I guess this was during the install-staging step? Because in install-target, 
we already explicitly rm all binaries in bzip2.mk.


  This is really a problem in the bzip2 upstream package itself. It's actually 
weird that it installs the executable three times, instead of symlinking or 
hardlinking...

  The underlying issue, I guess, is that you are using a pre-installed custom 
external toolchain, which has bzip2 installed in its sysroot as absolute 
symlinks. When buildroot copies this to the staging directory, the symlink is 
kept, but it points to a file which is not writable by you. So when bzip2 tries 
to overwrite it, it goes through the symlink, and fails to overwrite the file in 
your pre-installed toolchain directory.


  There are a couple of solutions possible:

1. In bzip2.mk, remove any existing bzip2 etc. like we do for target install.

2. In bzip2.mk, use custom staging install commands like we do for host-bzip2 - 
we anyway only need the libraries.

3. Add a patch to the package that fixes the Makefile to use 
--remove-destination, or to use install. This could be combined with using a 
hardlink instead. Probably the 20-legacy patch from debian already solves it, 
because I expect that you only have a problem with bunzip2 and bzcat, not with 
bzip2.



  Regards,
  Arnout



>
> Can someone please help me out? Thank you for your help.
> Regards
>
> Santhosh
>
> -- 
> Greater the Difficulty....Sweeter is the Victory
>
>
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-- 
Arnout Vandecappelle arnout at mind be
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