Re: [PATCH 4/6] BC: user interface (syscalls)

From: Kirill Korotaev
Date: Fri Aug 25 2006 - 06:51:27 EST


Alexey Dobriyan wrote:
On Thu, Aug 24, 2006 at 12:04:16PM +0100, Alan Cox wrote:

Ar Mer, 2006-08-23 am 21:35 -0700, ysgrifennodd Andrew Morton:

Its a uid_t because of setluid() and twenty odd years of existing unix
practice.


I don't understand. This number is an identifier for an accounting
container, which was somehow dreamed up by userspace.

Which happens to be a uid_t. It could easily be anyother_t of itself and
you can create a container_id_t or whatever. It is just a number.

The ancient Unix implementations of this kind of resource management and
security are built around setluid() which sets a uid value that cannot
be changed again and is normally used for security purposes. That
happened to be a uid_t and in simple setups at login uid = luid = euid
would be the norm.

Thus the Linux one happens to be a uid_t. It could be something else but
for the "container per user" model whatever a container is must be able
to hold all possible uid_t values. So we can certainly do something like

typedef uid_t container_id_t;


What about cid_t? Google mentions cid_t was used in HP-UX specific IPC (only if
_INCLUDE_HPUX_SOURCE is defined).
bcid_t?

Thanks,
Kirill
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