Re: [Ltib] CTRL-C over serial console

[aaron]

That worked for me also.  I was editing the file by hand, so I missed out
on the '-' character.  Putting it in enables the control-c.

Thanks

> Hi Aaron,
>
> Thanks for that.  Note also that in later LTIB versions, we have (when
> configured to directly logging into a shell):
>
> ::respawn:-/bin/sh
>
> This invokes some processing in busybox that allows control-c to work.
> The advantage is that you don't need to know the tty that you're logged
> into.
>
> Regards, Stuart
>
>
> address@hidden wrote:
>> I don't know if anyone else has run into this before, but I thought I
>> would post it for reference since it took me some digging to figure out.
>> I had changed my /etc/inittab file to launch a shell instead of the
>> getty
>> command for the respawn action, and noticed that ctrl-c didn't deliver
>> SIGINT to the foreground application, so I couldn't kill applications as
>> I
>> was used to doing.
>>
>> The line I had was this:
>>
>> ::respawn:/bin/sh
>>
>> Without changes to busybox or the kernel, ctrl-c functionality can be
>> restored by assigning a controlling terminal to the shell application.
>> To
>> do this, select something other than the default device for busybox,
>> which
>> is /dev/console.  I changed the line to this:
>>
>> ttyS0::respawn:/bin/sh
>>
>> A good explanation is here:
>>
>> http://lists.busybox.net/pipermail/busybox/2002-June/006397.html
>>
>> I'll copy the relevant part of the explanation below.
>>
>> - Aaron
>>
>> ----
>>
>> It looks like everyone is taking a swing at this one, so I think I'll
>> join in.  First off, the easiest way I've found to track down why
>> ctrl-c doesn't work is to just run "ps -j".  For ctrl-c to work, you
>> need a controlling terminal (the TTY column) and a process group.  If
>> you have a '?' in the TTY column, ctrl-c won't work.  In the past I
>> have seen this happen because of this code in drivers/char/tty_io.c:
>>         if (device == SYSCONS_DEV) {
>>                 struct console *c = console_drivers;
>>                 while(c && !c->device)
>>                         c = c->next;
>>                 if (!c)
>>                         return -ENODEV;
>>                 device = c->device(c);
>>                 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/console
>> block */
>>                 noctty = 1;
>>         }
>> Note that O_NOCTTY (no controlling terminal) is forced on whenever
>> /dev/console is opened (noctty = 1).  Possible workarounds:
>>   1) Run getty on something other than /dev/console.  For example,
>>      if you console is on the first serial port, run getty on
>> /dev/ttyS0.
>>      I believe this is the "correct" answer.
>>   2) You could also change getty to do a TIOCSCTTY ioctl explicitly
>> after
>>      it has opened the terminal.
>>   3) You could remove the forcing of noctty on from tty_io.c
>>
>>     Scott Anderson
>>     scott_anderson at mvista.com   MontaVista Software Inc.
>>     (408)328-9214               1237 East Arques Ave.
>>     http://www.mvista.com       Sunnyvale, CA  94085
>>
>>
>>
>