Re: [PATCH] tty: Add EXTPROC support for LINEMODE

[Howard Chu <hyc@symas.com>]

Ping... any other issues with this patch?

hyc@symas.com wrote:
> This patch is against the 2.6.34 source.
>
> 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.  This allows the process on the server side of the pty
>       to know when the state of the terminal has changed; it can then
>       issue the appropriate ioctl to retrieve the new state.
>
> 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 historical reference, a good copy of the relevant files can be found here: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@symas.com>


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