[elbe-devel] [PATCH] filesystem: make Filesyste.realpath() handle absolute paths in links
Torben Hohn
torben.hohn at linutronix.de
Tue Jun 18 09:22:10 CEST 2019
On Mon, Jun 17, 2019 at 06:43:45PM +0200, Olivier Dion wrote:
> I've wrote a dozen of cases .. It cover them all .. I hope it does for
> you too. Commit is pushed on devel/dion/issue-199
>
>
> Signed-off-by: Olivier Dion <dion at linutronix.de>
ok. this looks good.
please fold it with
f035d693386c ("Add 'realpath' method to 'Filesystem'")
and add
Reviewed-by: Torben Hohn <torben.hohn at linutronix.de>
then rebase onto master, and send me a pull request.
Thanks a lot for this work.
> ---
> elbepack/filesystem.py | 44 ++++++++++++++++++++++++++++++++++----------
> 1 file changed, 34 insertions(+), 10 deletions(-)
>
> diff --git a/elbepack/filesystem.py b/elbepack/filesystem.py
> index 4c925d1c..450f1524 100644
> --- a/elbepack/filesystem.py
> +++ b/elbepack/filesystem.py
> @@ -85,26 +85,50 @@ class Filesystem(object):
> os.makedirs(self.fname(path))
>
> def realpath(self, path):
> - if path[0] != os.sep:
> - path = os.sep + path
> +
> path = path.split(os.sep)
> path.reverse()
> + following = []
> real_path = [self.path]
> +
> while path:
> candidate = path.pop()
> +
> + # Don't care
> if candidate == '' or candidate == os.curdir:
> continue
> - elif candidate == os.pardir:
> +
> + # Can't go out of RFS
> + if candidate == os.pardir:
> + if following:
> + following.pop()
> if len(real_path) > 1:
> real_path.pop()
> - else:
> + continue
> +
> + parent = os.sep.join(real_path)
> + new_path = os.path.join(parent, candidate)
> + if not os.path.islink(new_path):
> + if following:
> + following.pop()
> real_path.append(candidate)
> - 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()
> + continue
> +
> + # Circular loop; Don't follow it
> + if new_path in following:
> + real_path.append(candidate)
> + continue
> +
> + following.append(new_path)
> + link = os.readlink(new_path)
> +
> + # Reset root for absolute link
> + if os.path.isabs(link):
> + real_path = [self.path]
> +
> + for element in reversed(link.split(os.sep)):
> + path.append(element)
> +
> return os.sep.join(real_path)
>
> def symlink(self, src, path, allow_exists=False):
> --
> 2.11.0Signed-off-by: Olivier Dion <dion at linutronix.de>
> ---
> elbepack/filesystem.py | 44 ++++++++++++++++++++++++++++++++++----------
> 1 file changed, 34 insertions(+), 10 deletions(-)
>
> diff --git a/elbepack/filesystem.py b/elbepack/filesystem.py
> index 4c925d1c..450f1524 100644
> --- a/elbepack/filesystem.py
> +++ b/elbepack/filesystem.py
> @@ -85,26 +85,50 @@ class Filesystem(object):
> os.makedirs(self.fname(path))
>
> def realpath(self, path):
> - if path[0] != os.sep:
> - path = os.sep + path
> +
> path = path.split(os.sep)
> path.reverse()
> + following = []
> real_path = [self.path]
> +
> while path:
> candidate = path.pop()
> +
> + # Don't care
> if candidate == '' or candidate == os.curdir:
> continue
> - elif candidate == os.pardir:
> +
> + # Can't go out of RFS
> + if candidate == os.pardir:
> + if following:
> + following.pop()
> if len(real_path) > 1:
> real_path.pop()
> - else:
> + continue
> +
> + parent = os.sep.join(real_path)
> + new_path = os.path.join(parent, candidate)
> + if not os.path.islink(new_path):
> + if following:
> + following.pop()
> real_path.append(candidate)
> - 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()
> + continue
> +
> + # Circular loop; Don't follow it
> + if new_path in following:
> + real_path.append(candidate)
> + continue
> +
> + following.append(new_path)
> + link = os.readlink(new_path)
> +
> + # Reset root for absolute link
> + if os.path.isabs(link):
> + real_path = [self.path]
> +
> + for element in reversed(link.split(os.sep)):
> + path.append(element)
> +
> return os.sep.join(real_path)
>
> def symlink(self, src, path, allow_exists=False):
> --
> 2.11.0
>
> On 2019-06-14T17:29:35+0200, Torben Hohn wrote:
>
> > 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
> > >
> > >
> > > _______________________________________________
> > > elbe-devel mailing list
> > > elbe-devel at linutronix.de
> > > https://lists.linutronix.de/mailman/listinfo/elbe-devel
>
> > --
> > Torben Hohn
> > Linutronix GmbH | Bahnhofstrasse 3 | D-88690 Uhldingen-Mühlhofen
> > Phone: +49 7556 25 999 18; Fax.: +49 7556 25 999 99
>
> > Hinweise zum Datenschutz finden Sie hier (Informations on data privacy
> > can be found here): https://linutronix.de/kontakt/Datenschutz.php
>
> > Linutronix GmbH | Firmensitz (Registered Office): Uhldingen-Mühlhofen |
> > Registergericht (Registration Court): Amtsgericht Freiburg i.Br., HRB700
> > 806 | Geschäftsführer (Managing Directors): Heinz Egger, Thomas Gleixner
>
>
> --
> Olivier Dion
> Linutronix GmbH | Bahnhofstrasse 3 | D-88690 Uhldingen-Mühlhofen
--
Torben Hohn
Linutronix GmbH | Bahnhofstrasse 3 | D-88690 Uhldingen-Mühlhofen
Phone: +49 7556 25 999 18; Fax.: +49 7556 25 999 99
Hinweise zum Datenschutz finden Sie hier (Informations on data privacy
can be found here): https://linutronix.de/kontakt/Datenschutz.php
Linutronix GmbH | Firmensitz (Registered Office): Uhldingen-Mühlhofen |
Registergericht (Registration Court): Amtsgericht Freiburg i.Br., HRB700
806 | Geschäftsführer (Managing Directors): Heinz Egger, Thomas Gleixner
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