Quoting Florian Weimer (fweimer@redhat.com):
On 04/15/2016 05:29 PM, Serge Hallyn wrote:
The current ttyname does the wrong thing in two cases:
1. If the passed-in link (say /proc/self/fd/0) points to a
device, say /dev/pts/2, in a parent mount namespace, and a
/dev/pts/2 exists (in a different devpts) in the current
namespace, then it returns /dev/pts/2. But /dev/pts/2 is
NOT the current tty, it is a different file and device.
Is this the first change?
Right, it ensures that the filesystem of the two files is
the same.
2. If the passed-in link (say /proc/self/fd/0) points to
a device, say /dev/pts/2, in a parent mount namespace, and
/dev/pts/2 does not exist in the current namespace, it
returns success but an empty name. As far as I can tell,
there is no reason for it to not return /proc/self/fd/0.
http://pubs.opengroup.org/onlinepubs/009695399/functions/ttyname.html
does not say anything about not returning a link.
Is it safe to drop the verification that ttyname ordinarily would do?
Which verification do you mean exactly?