[Duplicity-talk] duplicity crashes on directory whose owner has a very long username

[Andrea Rota]

hi,
I've recently been investigating a duplicity problem with the help of
the fine folks at rsync.net as I was trying to set up a backup to their
remote backup service.

while backing up a /var/mail folder, I kept getting the same error:

Traceback (most recent call last):
  File "/usr/bin/duplicity", line 373, in ?
    if __name__ == "__main__": main()
  File "/usr/bin/duplicity", line 366, in main
    if not sig_chain: full_backup(col_stats)
  File "/usr/bin/duplicity", line 142, in full_backup
    bytes_written = write_multivol("full", tarblock_iter, globals.backend)
  File "/usr/bin/duplicity", line 78, in write_multivol
    globals.gpg_profile)
  File "/usr/lib/python2.3/site-packages/duplicity/gpg.py", line 213, in 
GPGWriteFile
    try: data = block_iter.next(bytes_to_go).data
  File "/usr/lib/python2.3/site-packages/duplicity/diffdir.py", line 407, in 
next
    result = self.process(self.input_iter.next(), size)
  File "/usr/lib/python2.3/site-packages/duplicity/diffdir.py", line 277, in 
get_delta_iter_w_sig
    (new_path, sig_path, sigTarFile))
  File "/usr/lib/python2.3/site-packages/duplicity/robust.py", line 31, in 
check_common_error
    try: return function(*args)
  File "/usr/lib/python2.3/site-packages/duplicity/diffdir.py", line 309, in 
get_delta_path_w_sig
    if not new_path.isreg(): sigTarFile.addfile(ti)
  File "/usr/lib/python2.3/site-packages/duplicity/tarfile.py", line 763, in 
addfile
    assert len(full_headers) % BLOCKSIZE == 0
AssertionError

After some more tests, I ended up writing a small script that would run
duplicity on each subfolder of /var/mail, to try to identify the
offending Maildirs. After quite some hundred of iterations, the script
identified the culprit: a couple of maildirs which looked exactly the
same as any other, but whose owner's username was unusually long:

h-mailman.lists-parcodimonza.info-statuto-admin
and
h-mailman.lists-parcodimonza.info-statuto-request

the traceback, when running duplicity on these single directories,
is:

Traceback (most recent call last):
  File "/usr/bin/duplicity", line 373, in ?
    if __name__ == "__main__": main()
  File "/usr/bin/duplicity", line 366, in main
    if not sig_chain: full_backup(col_stats)
  File "/usr/bin/duplicity", line 142, in full_backup
    bytes_written = write_multivol("full", tarblock_iter, globals.backend)
  File "/usr/bin/duplicity", line 79, in write_multivol
    else: at_end = gpg.GzipWriteFile(tarblock_iter, tdp.name)
  File "/usr/lib/python2.4/site-packages/duplicity/gpg.py", line 254, in 
GzipWriteFile
    try: new_block = block_iter.next(bytes_to_go)
  File "/usr/lib/python2.4/site-packages/duplicity/diffdir.py", line 407, in 
next
    result = self.process(self.input_iter.next(), size)
  File "/usr/lib/python2.4/site-packages/duplicity/diffdir.py", line 277, in 
get_delta_iter_w_sig
    (new_path, sig_path, sigTarFile))
  File "/usr/lib/python2.4/site-packages/duplicity/robust.py", line 31, in 
check_common_error
    try: return function(*args)
  File "/usr/lib/python2.4/site-packages/duplicity/diffdir.py", line 309, in 
get_delta_path_w_sig
    if not new_path.isreg(): sigTarFile.addfile(ti)
  File "/usr/lib/python2.4/site-packages/duplicity/tarfile.py", line 763, in 
addfile
    assert len(full_headers) % BLOCKSIZE == 0
AssertionError

I tried creating directories with arbitrary, and arbitrarily long names,
but the name of the directories doesn't seem to give any problems;
however, as I chown these directories to one of these users, duplicity
crashes with the second traceback above.

I take it could be a tar error maybe (I tried to navigate through
duplicity source code, but I'm not really a Python person), however has
anybody else experienced similar problems before? My googling didn't
point to any references.

best,
a~

-- 
Andrea Rota
_________________________________________________________________
             Xelera             |  w: http://xelera.it
 Free Software Infrastructures  |  e: address@hidden
      Free Software Consulting  |  f: +39-039-9519837

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