[PATCH] modsign: hide openssl output in silent builds

[David Howells]

Arnd Bergmann <arnd at arndb.de> wrote:

> When a user calls 'make -s', we can assume they don't want to
> see any output except for warnings and errors, but instead
> they see this for a warning free build:
> 
>  ###
>  ### Now generating an X.509 key pair to be used for signing modules.
>  ###
>  ### If this takes a long time, you might wish to run rngd in the
>  ### background to keep the supply of entropy topped up.  It
>  ### needs to be run as root, and uses a hardware random
>  ### number generator if one is available.
>  ###
>  Generating a 4096 bit RSA private key
>  .................................................................................................................................................................................................................................++
>  ..............................................................................................................................++
>  writing new private key to 'certs/signing_key.pem'
>  -----
>  ###
>  ### Key pair generated.
>  ###
> 
> The output can confuse simple build testing scripts that just check
> for an empty build log.
> 
> This patch silences all the output:
>  - "echo" is changed to "@$(kecho)", which is dropped when "-s" gets
>    passed
>  - the openssl command itself is only printed with V=1, using the
>    $(Q) macro
>  - The output of openssl gets redircted to /dev/null on "-s" builds.
> 
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>

Applied.

David