[Buildroot] [PATCH 1/2] Add dependency on bash to gzip for runtime

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear Jonathan Ben Avraham,

On Thu, 17 Sep 2015 19:33:24 +0300 (IDT), Jonathan Ben Avraham wrote:

> > Then we should probably patch the problem and send upstream. gzip bundled
> > scripts are pretty trivial, and AFAICS, should work under any POSIX-like
> > shell.
> 
> But we would at least need to ln -s /bin/<ash|dash> /bin/bash in 
> Buildroot, no? so maybe the upstream fix is to change the hashbangs from 
> /bin/bash to /bin/sh. Do you really think that the gzip upstream would 
> accept this?

All the gzip scripts are in fact generated. zgrep is generated from
zgrep.in. zgrep.in contains:

#!/bin/sh

which gets replaced by the gzip Makefile.am by the value of $(SHELL):

SUFFIXES = .in
.in:
        $(AM_V_GEN)sed \
                -e 's|/bin/sh|$(SHELL)|g' \
                -e 's|[@]bindir@|'\''$(bindir)'\''|g' \
                -e 's|[@]GREP@|$(GREP)|g' \
                -e 's|[@]VERSION@|$(VERSION)|g' \
                $(srcdir)/$@.in >$@-t \
          && chmod a+x $@-t \
          && mv $@-t $@

Which is completely wrong, because it makes the assumption that
$(SHELL) on your build machine is going to be available on your target.

So your patch is in fact wrong I believe, because if someone is using
zsh, or tcsh or some other shell on their build machine, $(SHELL) will
point to this shell and not to bash, and the scripts generated by gzip
will use zsh/tcsh, etc. on the target.

So the proper way is most likely to adjust the gzip build system so
that we can pass at configure time a different value for the shell path
on the target (and it would default to $(SHELL) is not passed).

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com