[elbe-devel] [PATCH] filesystem: make Filesyste.realpath() handle absolute paths in links

[Torben Hohn]

the realpath() implementation is still not correct.
but i like the approach.

please finish it. and fold my patch into it.



On Fri, Jun 14, 2019 at 05:28:04PM +0200, Torben Hohn wrote:
> the current implementation fails for absolute links:
> 
> >>> from elbepack import filesystem
> >>> f = filesystem.Filesystem('xxx')
> >>> f.mkdir_p('/usr/bin')
> >>> f.symlink('/usr/bin/vim', '/usr/bin/omg')
> >>> f.realpath('/usr/bin/omg')
> '/home/torbenh/elbe/elbe/xxx/usr/bin/usr/bin/vim'
> >>>
> 
> handle it by "initialising" path again, when an absolute path
> is returned from os.readlink()
> 
> this still lacks catching recursive links, and i think, that .. is
> not evaluated properly in any case.
> 
> Signed-off-by: Torben Hohn <torben.hohn at linutronix.de>
> ---
>  elbepack/filesystem.py | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/elbepack/filesystem.py b/elbepack/filesystem.py
> index 4c925d1c6..91dbe0879 100644
> --- a/elbepack/filesystem.py
> +++ b/elbepack/filesystem.py
> @@ -102,9 +102,14 @@ class Filesystem(object):
>                  new_path = os.sep.join(real_path)
>                  if os.path.islink(new_path):
>                      elements = os.readlink(new_path)
> -                    for element in reversed(elements.split(os.sep)):
> -                        path.append(element)
> -                    real_path.pop()
> +                    if os.path.isabs(elements):
> +                        path = elements.split(os.sep)
> +                        path.reverse()
> +                        real_path = [self.path]
> +                    else:
> +                        for element in reversed(elements.split(os.sep)):
> +                            path.append(element)
> +                        real_path.pop()
>          return os.sep.join(real_path)
>  
>      def symlink(self, src, path, allow_exists=False):
> -- 
> 2.11.0
> 
> 
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-- 
Torben Hohn
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