On Sun, Dec 30, 2012 at 8:07 PM, Albert Hopkins <mar...@letterboxes.org>wrote: > > > On Sun, Dec 30, 2012, at 01:57 PM, Nicholas Cole wrote: > > Dear List, > > I'm hoping to use the tarfile module in the standard library to move some > files between computers. > > I can't see documented anywhere what this library does with userids and > groupids. I can't guarantee that the computers involved will have the same > users and groups, and would like the archives to be extracted so that the > files are all owned by the extracting user. > > Essentially, I do *not* with to preserve the owner and groups specified in > the archives. > > > Each "member" in the tar file has misc. metadata associated with it, which > can be retrieved with the get_info() method. You can add/modify this > metadata if creating a TarFile. > > However, it should be stated that by default (on *nix anyway) if the user > is not root then user/groups are assigned to the user exctracting the file > (because only root can assign userids/non-member-groups). The TarFile > extract*() methods pretty much inherit the same behavior as the *nix tar > command. So if you are extracting as a non-root user, you should expect > the same behavoir. If you are extracting as root but don't want to change > user/groups may have to extract it manually or create your own class by > inheriting TarFile and overriding the .chown() method. > >
Thank you for this. I guess that since the behaviour is not defined in the documentation, it would probably be safest to inherit and change chown into a no op. I know that on *most* systems these days ordinary users cannot chown, and also that people shouldn't be running things as root. But you can't be too careful - and predicting what a given user will do is always dangerous! Best wishes, N.
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