1 files changed, 92 insertions, 0 deletions
diff --git a/tar_fix.py b/tar_fix.py
new file mode 100755
index 0000000..d2817a2
--- /dev/null
+++ b/tar_fix.py
@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+
+import tarfile
+import os
+
+
+class Tarball:
+    def __init__(self, infile, outfile):
+        self.infile = infile
+        self.outfile = outfile
+
+    def drop_lead_comp(self):
+        """Removes leading path component (top-level dir)
+           from input tar file."""
+        with tarfile.open(self.infile) as tarin, tarfile.open(self.outfile, 'w:gz') as tarout:
+
+            # Identify common top-level dir for all tarball
+            # components, and proceed if it's set.
+            lead_comp_name = os.path.commonpath(tarin.getnames())
+
+            if lead_comp_name:
+                prefix_len = len(lead_comp_name + '/')
+                # Remove top-level dir (eg. "root.x86_64" or "root.i686"
+                # in Hyperbola bootstrap tarballs) from the archive.
+                tarin.members.remove(tarin.getmember(lead_comp_name))
+
+                for m in tarin.members:
+                    # Drop top-level dir prefix in all tarball
+                    # component's paths.
+                    m.path = m.path[prefix_len:]
+                    # If component is a link, don't fetch its content.
+                    # There's no point to that, and it helps avoiding
+                    # KeyError("linkname 'something' not found") on "broken"
+                    # symlinks, which are perfectly normal in a
+                    # root FS tarball. And for hard links, the link
+                    # target needs to be stripped of the prefix same as
+                    # the file name.
+                    if m.linkname:
+                        if m.islnk():
+                            m.linkname = m.linkname[prefix_len:]
+                        tarout.addfile(m)
+                    else:
+                        tarout.addfile(m, tarin.extractfile(m))
+
+
+if __name__ == '__main__':
+    import argparse
+
+    parser = argparse.ArgumentParser(
+        description="Remove leading path component from input tarball contents and save "
+        "the result in output tarball.", add_help=False)
+
+    group = parser.add_argument_group("Arguments")
+    group.add_argument("--help", action='store_true',
+                       help="Show this help message and exit.")
+
+    args = parser.parse_known_args()
+
+    group.add_argument("--input", metavar='PATH', dest='infile',
+                       type=str, help="Input tar[.gz/xz/bz2] file path.",
+                       required=True)
+    group.add_argument("--output", metavar='PATH', dest='outfile',
+                       type=str, help="Output tar.gz file path.",
+                       required=True)
+
+    if args[0].help:
+        parser.exit(parser.print_help())
+    else:
+        args = parser.parse_args()
+
+        tarball = Tarball(args.infile, args.outfile)
+        tarball.drop_lead_comp()
+
+# An error handling attempt I would like to remember. Note to self: it skips symlinks altogether.
+#
+# # Handle broken symlinks. They are perfectly normal in a root fs tarball, but tarfile module is not
+# # prepared for that. Trying hard not to catch anything other than "linkname 'something' not found".
+# try:
+#     # Write each modified component to output tarball.
+#     tarout.addfile(m, tarin.extractfile(m))
+#
+# except KeyError as error:
+#     if "linkname '" and "' not found" in str(error):
+#         print("Warning: the input tarball contains a dead symlink: '%s' to non-existent '%s'. No "
+#               "biggy, but you might want to know. It will be included in the output tarball as it "
+#               "is. Proceeding..." % (m.name, m.linkname), file=sys.stderr)
+#     else:
+#         raise
+
+# And a compound list for all tar members:
+#
+# [m.path[prefix_len:] for m in tarin.members]