Re: [PATCH v2] linux ttyname and ttyname_r: do not return wrong results

[Christian Brauner <christian dot brauner at canonical dot com>]

On Thu, Nov 24, 2016 at 03:48:58AM +0300, Dmitry V. Levin wrote:
> On Tue, Nov 22, 2016 at 03:29:53AM +0100, Christian Brauner wrote:
> > If a link (say /proc/self/fd/0) pointing to a device, say /dev/pts/2, in a
> > parent mount namespace is passed to ttyname, 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.
> > 
> > Detect this case and return ENODEV. Userspace can choose to take this as a hint
> > that the fd points to a tty device but to act on the fd rather than the link.
> > 
> > Signed-off-by: Serge Hallyn <serge@hallyn.com>
> > Signed-off-by: Christian Brauner <christian.brauner@canonical.com>
> > ---
> > Changelog: 2016-11-08
> > 	- remove obsolete comment in ttyname_r.c
> > 	- move is_pty() to common header file and mark as static inline
> > Changelog: 2016-11-22
> > 	- remove unneeded sys/symacros.h header
> > ---
> >  sysdeps/unix/sysv/linux/ttyname.c   | 16 ++++++++++++----
> >  sysdeps/unix/sysv/linux/ttyname.h   | 35 +++++++++++++++++++++++++++++++++++
> >  sysdeps/unix/sysv/linux/ttyname_r.c | 17 +++++++++++++----
> >  3 files changed, 60 insertions(+), 8 deletions(-)
> >  create mode 100644 sysdeps/unix/sysv/linux/ttyname.h
> 
> Could you add a properly formatted GNU-style ChangeLog entry for this
> change, please? (https://sourceware.org/glibc/wiki/Contribution%20checklist#Properly_Formatted_GNU_ChangeLog)

Will send a new version with the requested changelog in a minute.

> 
> [...]
> > diff --git a/sysdeps/unix/sysv/linux/ttyname.h b/sysdeps/unix/sysv/linux/ttyname.h
> > new file mode 100644
> > index 0000000..19af6e6
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/ttyname.h
> > @@ -0,0 +1,35 @@
> > +/* Copyright (C) 2004-2016 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> 
> This file looks like a new one, so could you explain where does this
> year range come from?

Sorry, the header file was copied over from another header file. I corrected the
year in the patch I'm going to send out in a minute.

> 
> BTW, the added copyright notice means that the change is legally
> significant.  If this is the case, could you explain your current
> FSF copyright assignment status, please?

So far I have not signed any FSF copyright assignment form. If this is
absolutely necessary, I will do so but since we were requested to add a new
simple header file it would be much appreciated if we could avoid this. At least
you could maybe apply the patch and then send me the form.

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