[PATCH] cttyhack: print detected ctty name when called without parameters

Alexander Shishkin virtuoso at slind.org
Mon Oct 31 17:22:34 UTC 2011


On Mon, 31 Oct 2011 16:58:09 +0100, Denys Vlasenko <vda.linux at googlemail.com> wrote:
> On Mon, Oct 31, 2011 at 4:10 PM, Alexander Shishkin <virtuoso at slind.org> wrote:
> > On Mon, 31 Oct 2011 13:21:01 +0100, Denys Vlasenko <vda.linux at googlemail.com> wrote:
> >> On Mon, Oct 31, 2011 at 12:25 PM, Denys Vlasenko
> >> <vda.linux at googlemail.com> wrote:
> >> > On Mon, Oct 31, 2011 at 1:15 AM, Alexander Shishkin <virtuoso at slind.org> wrote:
> >> >> Sometimes there's a need to figure out the controlling tty from a shell
> >> >> script, for example, to obtain a line for getty.
> >> >> In this case it's easier
> >> >> to call cttyhack than trying to repeat some of the cttyhack's logic.
> >> >
> >> > "cttyhack getty 0 -" should work, right?
> >> >
> >> >
> >> >> +       /* If it's a /dev/tty, still make sure it's wired to std{in,out,err} */
> >> >> +       fd = open_or_warn(console, O_RDWR);
> >> >> +       if (fd < 0)
> >> >> +               goto ret;
> >> >> +       //bb_error_msg("switching to '%s'", console);
> >> >> +       dup2(fd, STDIN_FILENO);
> >> >> +       dup2(fd, STDOUT_FILENO);
> >> >> +       xmove_fd(fd, STDERR_FILENO);
> >> >
> >> > Think what would happen if fd = 1
> >>
> >> Fixed it and applied to git. Thanks.
> >
> > Thanks, except for now there is a problem with the serial test going
> > before the sysfs test, and the former is almost never accurate as very
> > few serial drivers use "ttyS" names these days. I'd say that the sysfs
> > test is the most relevant for the cttyhack purposes.
> 
> Then we need to stop lying that cttyhack "analyzes stdin with various ioctls"...
> 
> I restored the order of checks.

Thanks!

Regards,
--
Alex


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