Hello Andrei On Fri, 10 Apr 2020 at 07:24, Andrey Vagin <avagin@xxxxxxxxxx> wrote: > > On Thu, Apr 9, 2020 at 2:35 PM Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote: > > > > Andrey Vagin <avagin@xxxxxxxxxx> writes: > > > > > On Tue, Apr 7, 2020 at 6:24 AM Michael Kerrisk (man-pages) > > > <mtk.manpages@xxxxxxxxx> wrote: > > > > > >> The clock-id identifies the clock whose offsets are being shown. > > >> This field is either 1, for CLOCK_MONOTONIC, or 7, for CLOCK_BOOT‐ > > >> TIME. > > >> > > >> What was the reason for exposing numeric clock IDs in the > > >> timens_offsets file? In API terms, that seems a little ugly. > > >> > > >> I think it would have been much nicer if the clocks were defined > > >> symbolically in this file. I.e., that reading the file would have > > >> shown something like > > >> > > >> monotonic x y > > >> boottime x y > > >> > > >> And that records similarly with symbolic clock names could have > > >> been written to the file. Was there a reason not to do this? > > > > > > No, there was not except that I haven't thought about this. I agree > > > that symbolic clock names looks nicer for humans, but numeric clock > > > IDs are a bit more convenient when we need to set/read offsets from > > > code. This interface is in the released kernel, so I think we can't > > > change the format of the content of this file. But we can add support > > > of symbolic clock names for setting clock offsets. What do you think? > > > > The rule is we can change things as long as userspace doesn't care. For > > very new interfaces like this it is possible there are few enough > > userspace programs that nothing cares. > > > > Do you know if someone is using this interface yet? > > CRIU has the support of time namespace, but these changes are in the > devel branch and have not been released yet. > > I know two more project: > * The util-linux (unshare and nsenter tools): > https://github.com/karelzak/util-linux/commit/7f1f0584c24a77909a7c96e62e30f63f4c1b10ad > https://github.com/karelzak/util-linux/commit/ef0341c9be441b834848d260ba0dbeb47a20f7a3 > > The last release of util-linux was at the end of January, so these > changes have not been released. > > * crun > https://github.com/containers/crun/commit/a669dc64f70f71423a0ee1bb977f2d77e473649a > > These changes have been released in the crun v0.13. > > All these projects only set offsets, so I think following the rule > that you described, we can start showing symbolic clock names and > accept both variants for setting offsets. If everyone agrees with > this, I can prepare a patch tomorrow. That would be great! Thank you! Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
