plugins/sources/tar.py: Consider link names in extraction

When extracting files from a base directory, we are normalizing
the TarInfo file names so we need to also normalize the link names
in the case of links and symlinks.

Fixes issue #155

1 files changed, 13 insertions, 0 deletions

diff --git a/buildstream/plugins/sources/tar.py b/buildstream/plugins/sources/tar.py
index 6a6cdd330..a93183ab0 100644
--- a/buildstream/plugins/sources/tar.py
+++ b/buildstream/plugins/sources/tar.py
@@ -96,6 +96,19 @@ class TarSource(DownloadableFileSource):
 
             # Now extract only the paths which match the normalized path
             if member.path.startswith(base_dir):
+
+                # If it's got a link name, give it the same treatment, we
+                # need the link targets to match up with what we are staging
+                #
+                # NOTE: Its possible this is not perfect, we may need to
+                #       consider links which point outside of the chosen
+                #       base directory.
+                #
+                if member.linkname:
+                    if member.linkname.startswith('./'):
+                        member.linkname = member.linkname[2:]
+                    member.linkname = member.linkname[l:]
+
                 member.path = member.path[l:]
                 yield member