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Re: [PATCH 1/1] linux ttyname: return link if appropriate
- From: Florian Weimer <fweimer at redhat dot com>
- To: Serge Hallyn <serge dot hallyn at ubuntu dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Fri, 15 Apr 2016 18:27:09 +0200
- Subject: Re: [PATCH 1/1] linux ttyname: return link if appropriate
- Authentication-results: sourceware.org; auth=none
- References: <20160415152929 dot GA7932 at ubuntumail>
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