New submission from Matthew Miller :
I have a tarfile with relative paths. The tail of tar tvf looks like this:
-rw-r--r-T nobody/nobody 1356 2012-02-28 19:25 s/772
-rw-r--r-- nobody/nobody 1304 2012-02-28 19:25 s/773
-rw-r--r-- nobody/nobody 1304 2012-02-28 19:25 s/774
-rw-r--r-- nobody/nobody 1304 2012-02-28 19:25 s/775
lrw-r--r-- nobody/nobody 0 2012-02-28 19:25 final -> s/772
The docs say:
TarFile.extractfile(member)
Extract a member from the archive as a file object. member
may be a filename or a TarInfo object. If member is a regular
file, a file-like object is returned. If member is a link, a
file-like object is constructed from the link’s target.
However, what I'm getting is this:
KeyError: "linkname '/s/772' not found"
It's appending a "/". Why?
Well, in tarfile.py:
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
Here, os.path.dirname(tarinfo.name) returns '', and then the "/" is appended,
giving an incorrect result.
One solution would be:
linkname = os.path.join(os.path.dirname(tarinfo.name),tarinfo.linkname)
but I don't think that works on platforms where os.sep is not "/", since tar
will want "/" in any case. But that's the correct logic.
I'm filing this against 2.7, but the same issue exists in 3.2.
A work-around in end-user code is to call Tarfile.getmember(filename), check if
the result issym(), and replace the result with
Tarfile.getmember(tarinfo.linkname). But since the extractfile function is
documented as following symlinks, that should not be necessary.
This bug isn't commonly encountered because by convention tarfiles usually
contain a subdirectory and everything goes in that. But we should do the right
thing.
--
components: Library (Lib)
messages: 154643
nosy: Matthew.Miller
priority: normal
severity: normal
status: open
title: Tarfile.extractfile fails to extract targets of top-level relative
symlinks
versions: Python 2.7
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<http://bugs.python.org/issue14160>
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