getty ignoring flags in /etc/gettydefs

[Roger Collins]

OK, wizards & unix question answerers, comp.bugs.sys5 wasn't interested,
so here goes:

Why can't a gettydef author have full control of the initial tty settings 
on a terminal by munging the gettydef entry?

More specifically, try setting IGNPAR in the initial settings field of a 
gettydef entry.  Then (after logging in on that terminal) do "stty -a".
You get "-ignpar" -- should have gotten "ignpar".  Why was the entry
in gettydefs ignored?

Here's why.  The following line of source in getty is executed after
the initial settings field has already been read and stored in
gptr->g_iflags (struct termio).  In find_def():

	gptr->g_iflags.c_iflag &= (ICRNL | ISTRIP | IXON | IXANY);

In V.3.2, the line is

	gptr->g_iflags.c_iflag  &= ICRNL;

This says ignore ALL initial settings except for ICRNL ISTRIP IXON and IXANY.
Or, in V.3.2, ignore all except ICRNL.  Why?

Am I missing something here?

Why doesn't it do the pure and simple:  Turn on the flags that are in the 
field -- don't turn on the ones that aren't.  That IS what is documented.

--
Roger Collins
NCR E&M Columbia
rogerc at ncrcae.Columbia.NCR.COM