Re: lib/48821: libedit EL_SETTY doesn't work

[YASUOKA Masahiko <yasuoka%iij.ad.jp@localhost>]

On Mon, 19 May 2014 13:50:01 +0000 (UTC)
christos%zoulas.com@localhost (Christos Zoulas) wrote:
>  While I like the refactoring of all tis duplicated code, the removal
>  of the conditional setting is undesirable.

I agree keeping the condition is safer, but I still cann't understand
what does the condition mean.

> It is meant to prevent the user for altering the state of the tty
> from a 3rd party.  Consider using the editor in the shell (which is
> used in /bin/sh). vi crashes and leaves the tty in non-canonical, no
> echo mode.

Yes,

>  With your change, the changes from vi get immediately reflected in
>  the editor.

The code can be simplified like below:

  tcsetattr(&ts);
  // ts = the current setting
  // ex = last termios for cooked mode
  // ed = last termios for rawmode

  if (ts != ex && ts != ed) {// the settings is changed by a 3rd party
     ex = ed = ts;    // adapt the change from the 3rd party
     ex |= setbits;   // adapt restriction from SETTY
     ex &= ~clrbits;  // same as above
     ed |= setbits;   // same as above
     ed &= ~clrbits;  // same as above
  }
  tcsetattr(&ed);     // reflect

My change was to remove the "if (..." condition.  So the removal of
the condition doesn't alter the behavior of "the changes from vi"
case.

But it alters the case in which the tty setting isn't changed.  In
that case, I think executing the conditional block isn't a problem,
since 'ts' is clean (because it's unchanged) and adapting the
restriction should be ok.

--yasuoka