Re: [PATCH v2] pty: show associative slave of ptmx in fdinfo

[Greg KH]

On Tue, Jul 18, 2017 at 06:27:59AM +0900, Masatake YAMATO wrote:
> This patch adds "tty-index" field to /proc/PID/fdinfo/N if N
> specifies /dev/ptmx. The field shows the index of associative
> slave pts.
> 
> Though a minor number is given for each pts instance, ptmx is not.
> It means there is no way in user-space to know the association between
> file descriptors for pts/n and ptmx. (n = 0, 1, ...)
> 
> This is different from pipe. About pipe such association can be solved
> by inode of pipefs.
> 
> Providing the way to know the association between pts/n and ptmx helps
> users understand the status of running system. lsof can utilize this field.
> 
> Signed-off-by: Masatake YAMATO <yamato@xxxxxxxxxx>
> ---
>  drivers/tty/pty.c          | 8 +++++++-
>  drivers/tty/tty_io.c       | 9 +++++++++
>  include/linux/tty_driver.h | 2 ++
>  3 files changed, 18 insertions(+), 1 deletion(-)

Sorry for the delay, now applied.

greg k-h