Re: [rdiff-backup-users] bug/crash on read-only file in incremental backup

[Josh Nisly]

Attached is a patch that fixes the problem for me. I get a slightly 
different traceback than was reported by others, but this is the correct 
solution. The problem is that Windows does not allow deletion of 
read-only files. This patch simply removes the readonly flag before 
removing the file. (This is the same behavior as Windows Explorer.)

Thanks,
JoshN

Andrew Ferguson wrote:
> Josh --
>
> You may or may not find this patch helpful when you are working on the 
> read-only files. This is my patch to support filesystem flags like 
> 'immutable' or 'secure delete' ... obviously when flags like 
> 'immutable' are set, it becomes important to unset it as necessary. 
> Follow the placement of the "make_fsflags_mutable" calls.
>
> I never incorporated this patch into CVS because 1) it needed to 
> switch to having tests in fs_abilities and 2) I needed to figure how 
> to detect support for chflags(2) -- I think Python 2.6 added chflags() 
> support, but I'll have to double-check.
>
> I suppose another piece of advice would be to watch for the places 
> where chmod() is called directly in the current rdiff-backup -- things 
> like chmod(0700 | file.perms()) are a good bet for places where we 
> need to adjust the permissions to make the backup work.
>
>
> Andrew
>
>
>
>
>
>
>
> On Nov 14, 2008, at 11:26 AM, Josh Nisly wrote:
>
> > I was planning on fixing this. Are you already working on it? If not, 
> > I'll try to send a patch in the next day or two.
> >
> > JoshN
> >
> > Andrew Ferguson wrote:
> > > On Nov 14, 2008, at 8:18 AM, Philip Warner wrote:
> > > > Hi,
> > > >
> > > > On windows, I get the following crash when doing an incremental on a
> > > > file that is read-only, but which has been updated.
> > > >
> > > > Googling produced the only other reference:
> > > >
> > > > http://lists.gnu.org/archive/html/rdiff-backup-users/2008-11/msg00011.html 
> > > >
> > > >
> > > > which went unanswered.
> > > >
> > > > Any suggestions?
> > >
> > >
> > > Philip --
> > >
> > > Thank you for bringing this issue up again. Somehow, I missed the 
> > > earlier post.
> > >
> > > I'll work on fixing this bug for the next release. On Unix, I 
> > > believe rdiff-backup generally handles this situation correctly. 
> > > From your traceback, it is clear that Windows returns 
> > > Windows-specific error codes in this instance, which rdiff-backup 
> > > was unprepared to handle.
> > >
> > >
> > > Andrew
> > >
> > >
> > > _______________________________________________
> > > rdiff-backup-users mailing list at address@hidden
> > > http://lists.nongnu.org/mailman/listinfo/rdiff-backup-users
> > > Wiki URL: 
> > > http://rdiff-backup.solutionsfirst.com.au/index.php/RdiffBackupWiki

--- rdiff_backup/rpath.py       12 Oct 2008 02:21:30 -0000      1.131
+++ rdiff_backup/rpath.py       14 Nov 2008 23:25:55 -0000
@@ -253,11 +253,13 @@
                        rp_source.delete()
                else:
                        try:
-                           rp_source.conn.os.rename(rp_source.path, 
rp_dest.path)
+                               rp_source.conn.os.rename(rp_source.path, 
rp_dest.path)
                        except OSError, error:
-                               if error.errno != errno.EEXIST: raise
+                               if error.errno != errno.EEXIST and \
+                                       error.errno != errno.EPERM: raise
 
                                # On Windows, files can't be renamed on top of 
an existing file
+                               rp_source.conn.os.chmod(rp_dest.path, 0700)
                                rp_source.conn.os.unlink(rp_dest.path)
                                rp_source.conn.os.rename(rp_source.path, 
rp_dest.path)
                            
@@ -1052,7 +1054,15 @@
                        except os.error:
                                if Globals.fsync_directories: self.fsync()
                                self.conn.shutil.rmtree(self.path)
-               else: self.conn.os.unlink(self.path)
+               else:
+                       try: self.conn.os.unlink(self.path)
+                       except OSError, error:
+                                       if error.errno == errno.EPERM:
+                                               # On Windows, read-only files 
cannot be deleted.
+                                               # Remove the read-only 
attribute and try again.
+                                               self.chmod(0700)
+                                               self.conn.os.unlink(self.path)
+
                self.setdata()
 
        def contains_files(self):