Re: [PATCH] resolv/resolv.h: allow alternative resolv.conf files

[Florian Weimer <fweimer at redhat dot com>]

On 08/17/2017 06:48 PM, Szabolcs Nagy wrote:
> On 17/08/17 17:24, Florian Weimer wrote:
>> resolv/tst-resolv-res_init-skeleton.c uses the support/ framework to
>> replace /etc in the test chroot, precisely because the /etc/resolv.conf
>> path is currently hard-coded.  The test does not need root permissions
>> to run on current Fedora, for instance.
> 
> how does chroot work without root on fedora?

See support_become_root:

bool
support_become_root (void)
{
#ifdef CLONE_NEWUSER
  if (unshare (CLONE_NEWUSER | CLONE_NEWNS) == 0)
    /* Even if we do not have UID zero, we have extended privileges at
       this point.  */
    return true;
#endif
  if (setuid (0) != 0)
    {
      printf ("warning: could not become root outside namespace (%m)\n");
      return false;
    }
  return true;
}

Florian