Re: [Qemu-devel] [PATCH] makefile: detect corrupted elf files

[Stefan Hajnoczi <stefanha@gmail.com>]

On Wed, May 22, 2013 at 12:46:45AM +0300, Michael S. Tsirkin wrote:
> Once in a while make gets killed and doesn't
> clean up partial object files after it.
> Result is nasty errors from link.
> This hack checks object is well formed before linking,
> and rebuilds it if not.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 
> Is below useful for others?
> 
>  Makefile.target | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Makefile.target b/Makefile.target
> index ce4391f..4dddee5 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -191,3 +191,10 @@ endif
>  
>  GENERATED_HEADERS += config-target.h
>  Makefile: $(GENERATED_HEADERS)
> +
> +.SECONDEXPANSION:
> +
> +.PHONY: CORRUPTBINARY
> +
> +$(all-obj-y): % : $$(if $$(shell size %), , CORRUPTBINARY)

How does size(1) establish the validity of the ELF file?  Is it possible
to sneak past a truncated file (which I think is the only type of
corruption you're trying to protect against)?

Stefan