[PATCH 0/2] tty: add EXTPROC support for LINEMODE

[Howard Chu]

Paraphrased from the 1989 BSD patch by David Borman @ cray.com:

    These are the changes needed for the kernel to support
    LINEMODE in the server.

    There is a new bit in the termios local flag word, EXTPROC.
    When this bit is set, several aspects of the terminal driver
    are disabled.  Input line editing, character echo, and mapping
    of signals are all disabled.  This allows the telnetd to turn
    off these functions when in linemode, but still keep track of
    what state the user wants the terminal to be in.

    New ioctl:
        TIOCSIG         Generate a signal to processes in the
                        current process group of the pty.

    There is a new mode for packet driver, the TIOCPKT_IOCTL bit.
    When packet mode is turned on in the pty, and the EXTPROC bit
    is set, then whenever the state of the pty is changed, the
    next read on the master side of the pty will have the TIOCPKT_IOCTL
    bit set, and the data will be the contents of a struct termios.
    This allows the process on the server side of the pty to know
    when the state of the terminal has changed, and what the new
    state is.

Since the original BSD patches accompanied the source code for telnet I've 
left that reference here, but obviously the feature is useful for any remote 
terminal protocol, including ssh.

The corresponding feature has existed in the BSD tty driver since 1989. For 
historical reference, a good copy of the relevant files can be found here:

http://anonsvn.mit.edu/viewvc/krb5/trunk/src/appl/telnet/?pathrev=17741

Signed-off-by: Howard Chu <hyc@xxxxxxxxx>

---
Howard Chu (2):
  Add EXTPROC tty support for Telnet LINEMODE
  Add arch-specific EXTPROC definitions

 arch/alpha/include/asm/ioctls.h     |    2 ++
 arch/alpha/include/asm/termbits.h   |    1 +
 arch/arm/include/asm/ioctls.h       |    2 ++
 arch/arm/include/asm/termbits.h     |    1 +
 arch/avr32/include/asm/ioctls.h     |    2 ++
 arch/avr32/include/asm/termbits.h   |    1 +
 arch/cris/include/asm/ioctls.h      |    2 ++
 arch/cris/include/asm/termbits.h    |    1 +
 arch/frv/include/asm/ioctls.h       |    2 ++
 arch/frv/include/asm/termbits.h     |    1 +
 arch/h8300/include/asm/ioctls.h     |    2 ++
 arch/h8300/include/asm/termbits.h   |    1 +
 arch/ia64/include/asm/ioctls.h      |    2 ++
 arch/ia64/include/asm/termbits.h    |    1 +
 arch/m32r/include/asm/ioctls.h      |    2 ++
 arch/m32r/include/asm/termbits.h    |    1 +
 arch/m68k/include/asm/ioctls.h      |    2 ++
 arch/m68k/include/asm/termbits.h    |    1 +
 arch/mips/include/asm/ioctls.h      |    3 ++-
 arch/mips/include/asm/termbits.h    |    1 +
 arch/mn10300/include/asm/ioctls.h   |    2 ++
 arch/mn10300/include/asm/termbits.h |    1 +
 arch/parisc/include/asm/ioctls.h    |    2 ++
 arch/parisc/include/asm/termbits.h  |    1 +
 arch/powerpc/include/asm/ioctls.h   |    2 ++
 arch/powerpc/include/asm/termbits.h |    1 +
 arch/s390/include/asm/ioctls.h      |    2 ++
 arch/sh/include/asm/ioctls.h        |    2 ++
 arch/sparc/include/asm/ioctls.h     |    2 ++
 arch/sparc/include/asm/termbits.h   |    1 +
 arch/xtensa/include/asm/ioctls.h    |    2 ++
 arch/xtensa/include/asm/termbits.h  |    1 +
 drivers/char/n_tty.c                |   25 ++++++++++++++++++++++---
 drivers/char/pty.c                  |   13 +++++++++++++
 drivers/char/tty_ioctl.c            |   18 ++++++++++++------
 fs/compat_ioctl.c                   |    1 +
 include/asm-generic/ioctls.h        |    2 ++
 include/asm-generic/termbits.h      |    1 +
 include/linux/tty.h                 |    1 +
 39 files changed, 101 insertions(+), 10 deletions(-)

--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/
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