Hi,
I’m interested in working on bug #248500 and have been looking into how UID allocation is currently handled by adduser. The main issue I’m trying to address is the distinction between avoiding currently allocated UIDs and avoiding reuse of UIDs that have been allocated in the past. The latter requires some form of persistent state, since once an account is removed there is no longer an entry in /etc/passwd from which adduser can determine that the UID was previously used. I also looked at the UID/GID pool functionality introduced in #1067845, in particular UID_POOL and RESERVE_UID_POOL. This provides a mechanism for reserving known UID assignments, but it does not appear to constitute a general history of previously allocated UIDs. I’m therefore interested in investigating whether the existing UID pool mechanism could be extended or reused to implement the semantics requested by #248500, while considering a few questions: 1. How should UIDs assigned by adduser be persisted so that they remain unavailable after the corresponding account is removed? 2. What should happen when an account is recreated, should it receive its previous UID or should that UID remain permanently unavailable? 3. How should existing systems be handled, where previously used UIDs are no longer present in /etc/passwd and therefore cannot be reconstructed reliably? 4. How should manually specified UIDs (--uid) interact with the mechanism? 5. Should system UIDs and regular user UIDs follow the same policy? 6. How should concurrent adduser invocations be handled to avoid allocating the same UID? Before starting an implementation, I’d like to check whether this approach matches the intended direction for #248500, and whether there are any previous proposals or design constraints I should take into account. If the bug is still considered open for development, I’d be happy to investigate this further and prepare a patch with tests. If, however, the issue has already been addressed by recent changes or is no longer considered relevant, I think the bug can be closed. Thanks, Juan Munoz Salsa: Juaesm
