Re: [Libguestfs] [PATCH nbdkit v2 3/3] ocaml: Add bindings for nbdkit_peer_{pid, uid, gid}.
On Mon, Oct 05, 2020 at 08:39:41AM -0500, Eric Blake wrote:
On 10/3/20 1:50 PM, Richard W.M. Jones wrote:
> ---
> plugins/ocaml/NBDKit.mli | 7 +++++++
> plugins/ocaml/NBDKit.ml | 4 ++++
> plugins/ocaml/bindings.c | 24 ++++++++++++++++++++++++
> 3 files changed, 35 insertions(+)
>
> diff --git a/plugins/ocaml/NBDKit.mli b/plugins/ocaml/NBDKit.mli
> index ececd5fd..8abfeb49 100644
> --- a/plugins/ocaml/NBDKit.mli
> +++ b/plugins/ocaml/NBDKit.mli
> @@ -162,3 +162,10 @@ val shutdown : unit -> unit
>
> (** Print a debug message when nbdkit is in verbose mode. *)
> val debug : ('a, unit, string, unit) format4 -> 'a
> +
> +(** Binding for [nbdkit_peer_pid]. *)
> +val peer_pid : unit -> int
> +(** Binding for [nbdkit_peer_uid]. *)
> +val peer_uid : unit -> int
> +(** Binding for [nbdkit_peer_gid]. *)
> +val peer_gid : unit -> int
Is int sufficient on 32-bit platforms, or do you need int32? But on
64-bit platforms, I don't see a system ever having enough valid
uid_t/gid_t/pid_t to overflow int to the point that int64 would have
been better.
We shouldn't assume that IDs are allocated sequentially, they might
be sparsely allocated. eg with containers and user namespaces, ranges
of UIDs/GIDs are reserved for specific users / containers to utilize.
eg on Fedora, my user account is reserved 65536 UIDs, starting at
an offset of 100000.
So it is entirely conceivable there could be a system which has very
few UIDs/GIDs/PIDs in use, but none the less has some allocated from
a range that is larger than INT32MAX
Regards,
Daniel
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