[LTP] [PATCH 1/2] Implement tst_setup_netns() helper function

[Petr Vorel]

> On 25. 11. 22 18:01, Petr Vorel wrote:
> > Hi Martin,

> > > +void tst_setup_netns(void)
> > > +{
> > > +	int real_uid = getuid();
> > > +	int real_gid = getgid();
> > > +	int nscount = 1;
> > > +
> > > +	if (!access("/proc/sys/user/max_user_namespaces", F_OK)) {
> > Out of curiosity, this can happen only on old kernel, which does not support
> > user namespaces (kernel < 3.8) ? I guess there must be other case,
> > I suppose you would not bother about 3.8, right?

> > Also asking that if not readable we don't TCONF (int nscount = 1).

> This is very much still happening on kernel 4.4.180 even though user
> namespaces are supported and enabled by default. That's why
> tst_setup_netns() fails with TCONF only when max_user_namespaces sysfile
> exists, is read-only AND the value inside is zero.

Makes sense.

And missing file: if I'm correct sysctl files were added in v4.9-rc1 in
25f9c0817c53 ("userns: Generalize the user namespace count into ucount")

Kind regards,
Petr