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

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

The following reply was made to PR lib/48821; it has been noted by GNATS.

From: YASUOKA Masahiko <yasuoka%iij.ad.jp@localhost>
To: christos%zoulas.com@localhost, gnats-bugs%NetBSD.org@localhost
Cc: lib-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, 
netbsd-bugs%netbsd.org@localhost
Subject: Re: lib/48821: libedit EL_SETTY doesn't work
Date: Wed, 21 May 2014 17:55:31 +0900 (JST)

 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