[Duplicity-talk] Crash on locked files

[Georg Lutz]

Hi Kenneth,

some time ago in April I reported a duplicicty crash under 
Windows/cygwin when doing backups of locked (Outlook) files. I tried 
your patches in robust.py and selection.py (which seems to be 
incorporated in current version) but unfourtunately this did not fix the 
crash. When I remember correctly there were also some difficulties in 
reproducing the issue.

However I have done further investigation on this topic and I found a 
way to easily reproduce the crash, even without the help of Outlook. :):

Open a python interactive shell and enter:

---
> > > import fcntl
> > > log = open("/cygdrive/d/temp/test.txt", "a+")
> > > fcntl.flock(log, fcntl.LOCK_EX)
---

This locks the file. However this is not the same as the native Windows 
exclusive lock - I am not able to open the file directly but it is still 
possible to copy the file and then open it. This is not the case with 
Windows exclusive locks which Outlook uses.

Now start a backup with

---
duplicity \
   --include '/cygdrive/d/temp/test.txt' \
   --exclude '**' \
   '/cygdrive' \
   file:///cygdrive/f/backups/duplicity/data
---

And voila duplicity crashes with

---
IOError: [Errno 13] Permission denied

Cleanup of temporary directory 
/cygdrive/f/backups/duplicity/archive/cad29640aad
cde263f75df5cb18bc779/duplicity-E011Oe-tempdir failed - this is probably 
a bug.
Cleanup of temporary directory 
/cygdrive/f/backups/duplicity/archive/cad29640aad
cde263f75df5cb18bc779/duplicity-JLcxVo-tempdir failed - this is probably 
a bug.
---

If you unlock the file with

> > > fcntl.flock(log, fcntl.LOCK_UN)

the backup works flawless.

If testes this with the latest version 0.6.02 .

Could you have a look at it please?



Regards
   Georg