Subject: Re: [PATCH 0/3] status: TTY status message request

From: Greg KH <[email-masked]>
Date: Wed, 26 Jan 2022 14:45:28 +0100

On Mon, Jan 17, 2022 at 08:42:57PM -0800, Walt Drummond wrote:
> This patchset adds TTY status message request feature to the n_tty
> line dicipline.  This feature prints a brief message containing basic
> system and process group information to a user's TTY in response to a
> new control character in the line dicipline (default Ctrl-T) or the
> TIOCSTAT ioctl.  The message contains the current system load, the
> name and PID of an interesting process in the forground process group,
> it's run time, percent CPU usage and RSS.  An example of this message
> is:
> 
>   load: 0.31  cmd: sleep 3616843 [sleeping] 0.36r 0.00u 0.00s 0% 696k
> 
> User API visible changes are limited to:
>  - The addition of VSTATUS in termios.c_cc[]
>  - The addition of NOKERNINFO bit in termios.l_cflags
>  - The addition of the TIOCSTAT ioctl number
> 
> None of these changes break the existing kernel api as the termios
> structure on all architectures has enough space in the control
> character array (.c_cc) for the new character, and the other changes
> are space agnostic.
> 
> This feature is in many other Unix-like systems, both current and
> historical.  In other implementations, this feature would also send
> SIGINFO to the process group; this implementation does not.
> 
> Walt Drummond (3):
>   vstatus: Allow the n_tty line dicipline to write to a user tty
>   vstatus: Add user space API definitions for VSTATUS, NOKERNINFO and
>     TIOCSTAT
>   status: Display an informational message when the VSTATUS character is
>     pressed or TIOCSTAT ioctl is called.
> 
>  arch/alpha/include/asm/termios.h         |   4 +-
>  arch/alpha/include/uapi/asm/ioctls.h     |   1 +
>  arch/alpha/include/uapi/asm/termbits.h   |  34 ++---
>  arch/ia64/include/asm/termios.h          |   4 +-
>  arch/ia64/include/uapi/asm/termbits.h    |  34 ++---
>  arch/mips/include/asm/termios.h          |   4 +-
>  arch/mips/include/uapi/asm/ioctls.h      |   1 +
>  arch/mips/include/uapi/asm/termbits.h    |  36 ++---
>  arch/parisc/include/asm/termios.h        |   4 +-
>  arch/parisc/include/uapi/asm/ioctls.h    |   1 +
>  arch/parisc/include/uapi/asm/termbits.h  |  34 ++---
>  arch/powerpc/include/asm/termios.h       |   4 +-
>  arch/powerpc/include/uapi/asm/ioctls.h   |   2 +
>  arch/powerpc/include/uapi/asm/termbits.h |  34 ++---
>  arch/s390/include/asm/termios.h          |   4 +-
>  arch/sh/include/uapi/asm/ioctls.h        |   1 +
>  arch/sparc/include/uapi/asm/ioctls.h     |   1 +
>  arch/sparc/include/uapi/asm/termbits.h   |  38 +++---
>  arch/xtensa/include/uapi/asm/ioctls.h    |   1 +
>  drivers/tty/Makefile                     |   2 +-
>  drivers/tty/n_tty.c                      | 113 +++++++++++-----
>  drivers/tty/n_tty_status.c               | 162 +++++++++++++++++++++++
>  drivers/tty/tty_io.c                     |   2 +-
>  include/asm-generic/termios.h            |   4 +-
>  include/linux/tty.h                      | 123 ++++++++---------
>  include/uapi/asm-generic/ioctls.h        |   1 +
>  include/uapi/asm-generic/termbits.h      |  34 ++---
>  27 files changed, 461 insertions(+), 222 deletions(-)
>  create mode 100644 drivers/tty/n_tty_status.c
> 
> -- 
> 2.30.2
> 

You forgot to cc: me on patch 2/3, which would be needed if I was to
take them all.

Please fix up patch 2 and resend the whole series.

thanks,

greg k-h