[rdiff-backup-users] [PATCH] Preserve symlink permissions

[Andrew Ferguson]

Hi,

Some Unix systems (at least the *BSDs and Mac OS X) set the permission
bits on symbolic links to "777 - umask" at link creation. This is
different from Linux, where all symbolic links are mode 777.

This patch changes rdiff-backup's umask temporarily when it creates
symbolic links so that their exact permissions are maintained during
backup and restore. The patch is against the current CVS repository, but
should also work for 1.1.x and 1.0.x versions.

Although the permission bits seem to have no effect, I created this
patch so that rdiff-backup comes even closer to making a perfect backup
on BSD-like systems. It has been tested on Linux, Mac OS X, and during
network backup and restore.

Cheers,
Andrew

-- 
Andrew Ferguson - address@hidden

diff -Nur rdiff-backup-cvs/rdiff_backup/rpath.py 
rdiff-backup-symlink-perms/rdiff_backup/rpath.py
--- rdiff-backup-cvs/rdiff_backup/rpath.py      2006-01-13 00:29:47.000000000 
-0500
+++ rdiff-backup-symlink-perms/rdiff_backup/rpath.py    2006-11-04 
15:55:39.000000000 -0500
@@ -100,7 +100,12 @@
 
        if rpin.isreg(): return copy_reg_file(rpin, rpout, compress)
        elif rpin.isdir(): rpout.mkdir()
-       elif rpin.issym(): rpout.symlink(rpin.readlink())
+       elif rpin.issym():
+               # some systems support permissions for symlinks, but
+               # only by setting at creation via the umask
+               os.umask(0777 - rpin.getperms())
+               rpout.symlink(rpin.readlink())
+               os.umask(077)   # restore rdiff-backup standard umask
        elif rpin.ischardev():
                major, minor = rpin.getdevnums()
                rpout.makedev("c", major, minor)