[rdiff-backup-users] UpdateError with hardlinked und suid files

[Christian Hattemer]

Hi,

I'm using rdiff-backup 1.0.5 on NetBSD 4.0 and found the following problem:

If the backup contains files that are both hardlinked and have set user id 
status and the writer-part of rdiff-backup is running as an unprivileged 
user, then rdiff-backup will only mirror the first name of each set of 
hardlinked files.

Example:
address@hidden:~ > rdiff-backup /usr/bin userbackup
UpdateError atq Updated mirror temp file userbackup/rdiff-backup.tmp.10 does 
not match source
UpdateError atrm Updated mirror temp file userbackup/rdiff-backup.tmp.11 does 
not match source
UpdateError batch Updated mirror temp file userbackup/rdiff-backup.tmp.18 
does not match source
UpdateError chpass Updated mirror temp file userbackup/rdiff-backup.tmp.40 
does not match source
UpdateError chsh Updated mirror temp file userbackup/rdiff-backup.tmp.41 does 
not match source
UpdateError passwd Updated mirror temp file userbackup/rdiff-backup.tmp.243 
does not match source
UpdateError systat Updated mirror temp file userbackup/rdiff-backup.tmp.335 
does not match source
UpdateError yppasswd Updated mirror temp file userbackup/rdiff-backup.tmp.404 
does not match source

The problematic files look like this:
address@hidden:/usr/bin > ll -i at atq atrm batch
8225590 -r-sr-xr-x  4 root  wheel   27K Nov 10 15:02 at
8225590 -r-sr-xr-x  4 root  wheel   27K Nov 10 15:02 atq
8225590 -r-sr-xr-x  4 root  wheel   27K Nov 10 15:02 atrm
8225590 -r-sr-xr-x  4 root  wheel   27K Nov 10 15:02 batch

In the mirror there's only at:
address@hidden:~/userbackup > ll at
-r-xr-xr-x  1 krille  users   27K Nov 10 15:02 at

The metatdata shows this:
File at
  Type reg
  Size 28147
  NumHardLinks 4
  Inode 8225590
  DeviceLoc 0
  ModTime 1194703348
  Uid 0
  Uname root
  Gid 0
  Gname wheel
  Permissions 2413

The other hardlinked names are missing.

If the writer-part of rdiff-backup is running as root, or if a file is only 
hardlinked or only suid, but not both at the same time, then everything is fine.

Could this be fixed?

BTW: Using --no-hard-links works around this problem. With this option 
everything runs fine where it otherwise doesn't. However it seems that this 
option doesn't operate as advertised in the man-page.

It says that the files won't be hardlinked on the mirror but that the 
information would still be preserved in the metadata. However the files are 
neither linked nor is the link information recorded in the metadata. Please 
fix the code or the man-page, at your option.

--
Bye, Chris