On Mon, Nov 20, 2017 at 02:06:23PM -0500, Steven Smith wrote:
> > > + if (readres == 0)
> > > + exit_slowly(EXIT_SUCCESS);
> >
> > I'm not sure about it. Maybe it would be better to assume that readres == 0
> > and no error is the same as c = 0. In this case functions returns NULL
> > and we try another speed setting (if defined) for the terminal.
>
> Hmm, maybe. The problem with that would be what happens if there isn't
> another speed configured (which would match the system I was looking at when
> I started looking at this). In that case, get_logname() will immediately retry
> the read, without doing anything to clear the end of file condition, which
> would be an infinite loop. Even if I configured multiple bauds, the test
> environment which originally saw the issue is a VCONSOLE, so the loop in main()
> which calls get_logname() would immediately retry without actually doing
> anything with the configured speed, which I don't think would have helped
> very much.
>
> Perhaps changing the baud on a real serial port would have cleared the end of
> file condition (or perhaps that's just showing my ignorance of how serial ports
> work)? That might make something like this more reasonable:
>
> @@ -2000,12 +2003,15 @@ static char *get_logname(struct options *op, struct termios *tp, struct chardata
> case ESRCH:
> case EINVAL:
> case ENOENT:
> - break;
> + exit_slowly(EXIT_SUCCESS);
> default:
> log_err(_("%s: read: %m"), op->tty);
> }
> }
>
> + if (readres == 0)
> + c = 0;
> +
> /* Do parity bit handling. */
> if (eightbit)
> ascval = c;
> @@ -2030,6 +2036,8 @@ static char *get_logname(struct options *op, struct termios *tp, struct chardata
> switch (key) {
> case 0:
> *bp = 0;
> + if (op->flags & F_VCONSOLE)
> + exit_slowly(EXIT_SUCCESS);
> if (op->numspeed > 1)
> return NULL;
Yes, that's what I've though about. I have committed a little bit modified
version:
- if (op->numspeed > 1)
+ if (op->numspeed > 1 && !(op->flags & F_VCONSOLE))
return NULL;
+ if (readres == 0)
+ exit_slowly(EXIT_SUCCESS);
break;
the speed configuration should be accepted only for !F_VCONSOLE. IMHO
the current code is weak (independently on your read() issue:-)
The another weak thing is that agetty don't care if all speeds has
been already tested. The next_speed() increments baud_index again and
again... maybe we need another exit_slow() here too.
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
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