[PATCH 1/1] linux ttyname: return link if appropriate

[Florian Weimer]

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?

> 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?

ttyname_r will need a similar change.

Florian