[CRIU] [PATCH 1/2] Re-create cgroups if necessary

[Tycho Andersen]

On Tue, Jun 24, 2014 at 06:04:52PM +0400, Pavel Emelyanov wrote:
> On 06/24/2014 05:38 PM, Tycho Andersen wrote:
> > Hi Pavel,
> > 
> > On Tue, Jun 24, 2014 at 10:53:26AM +0400, Pavel Emelyanov wrote:
> >> On 06/23/2014 07:54 PM, Tycho Andersen wrote:
> >>> If a task had cgroups, these should be restored. (Also any properties of
> >>> cgroups, but this commit doesn't do that yet.)
> >>>
> >>> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> >>> ---
> >>>  cgroup.c       |  6 +++++-
> >>>  include/util.h |  5 +++++
> >>>  util.c         | 26 ++++++++++++++++++++++++++
> >>>  3 files changed, 36 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/cgroup.c b/cgroup.c
> >>> index 2d9ebad..8b2deb2 100644
> >>> --- a/cgroup.c
> >>> +++ b/cgroup.c
> >>> @@ -258,9 +258,13 @@ static int move_in_cgroup(CgSetEntry *se)
> >>>  		int fd, err;
> >>>  		ControllerEntry *ce = se->ctls[i];
> >>>  
> >>> +		sprintf(aux, "%s/%s", ce->name, ce->path);
> >>> +		if (mkdirpat(cg, aux) < 0)
> >>> +			return -1;
> >>> +
> >>>  		sprintf(aux, "%s/%s/tasks", ce->name, ce->path);
> >>>  		pr_debug("  `-> %s\n", aux);
> >>> -		err = fd = openat(cg, aux, O_WRONLY);
> >>> +		err = fd = openat(cg, aux, O_WRONLY | O_CREAT, 0700);
> >>
> >> Why O_CREAT here? The cgroup files should just exist.
> > 
> > I guess it won't exist if the directory is created by mpdirpat above,
> 
> It should, since it's cgroupfs, which populates directories with
> files once they are created. And the "tasks" file is one of such.

Ah, yes. A quick test shows it does work without O_CREAT there.

Tycho