[Buildroot] [PATCH 2/2] toolchain/helper: don't follow symlinks when copying libs to target

[Yann E. MORIN <yann.morin.1998@free.fr>]

Arnout, All,

On 2016-05-30 00:33 +0200, Arnout Vandecappelle spake thusly:
> On 05/29/16 23:12, Yann E. MORIN wrote:
> > Thomas DS, All,
> > 
> > On 2016-05-29 20:54 +0200, Thomas De Schampheleire spake thusly:
> [snip]
> >> While the trailing slash is indeed a fine solution, it is kind of dirty.
> >> I wonder if -H would do the trick too:
> > [--SNIP--]
> >> It should make sure that only STAGING_DIR is resolved, not any other
> >> symbolic link encountered.
> > 
> > Well, appending a slash is a sure mean to make it sure the target of the
> > symlink (if it is a symlink to start with) is entered. I don't see where
> > it is dirty.
> 
>  I should have realized this before, but: when is $(STAGING_DIR) ever a symlink?
> It's defined as $(HOST_DIR)/usr/$(GNU_TARGET_NAME)/sysroot and it's explicitly
> mkdir'ed in the Makefile. It's not a symlink. $(O)/staging is a symlink, but
> that's not what's used here.
> 
>  That makes me think there must have been a different reason why Thomas added
> the -L. Thomas originally wrote:
> 
>   I used -follow just to make sure that STAGING_DIR is entered. It seems
>   to work without just because STAGING_DIR happens to be defined with a
>   trailing slash, in which case its contents are evaluated anyhow by
>   find. I considered this dependency too fragile and wanted it to work
>   even if someone optimizes away the trailing slash. Another solution
>   would be to add a trailing slash manually as $(STAGING_DIR)/ but -L is
>   much cleaner.
> 
> Note that there never has been a trailing / in STAGING_DIR.
> 
>  Thomas, any idea what is going on here?
> 
>  I did a quick try with just removing -L and it seems to work fine.
> 
> 
> > 
> > Yes, -H does the job, too. But I think it is better that we append a
> > slash: it makes it explicit we want to treat it as a directory, not a
> > potential symlink.
> > 
> > However, why would we need to handle the symlink case, to begin with? We
> > are controlling the variable passed in this case and it points to a copy
> > of the sysroot we did make. I.e. that variable is not provided by the
> > user; it is always filled by our infra.
> 
>  Yann, did you mean the same thing as I described above?

Basically, yes.

Regards,
Yann E. MORIN.

>  Regards,
>  Arnout
> 
> > 
> > Surely, if we really, really, like really-really, want to make it
> > explicit we want the directory pointed-to by the symlink, then, we
> > should probably do:
> > 
> >     find $$(readlink -f $(STAGING_DIR)) -name blabla
> > 
> > Regards,
> > Yann E. MORIN.
> > 
> 
> 
> -- 
> Arnout Vandecappelle                          arnout at mind be
> Senior Embedded Software Architect            +32-16-286500
> Essensium/Mind                                http://www.mind.be
> G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
> LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
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