[OE-core] [PATCH] sysvinit-inittab: support non-busybox-getty on serial consoles

[André Draszik]

On Fri, 2019-02-08 at 14:07 +0000, Richard Purdie wrote:
> On Fri, 2019-02-08 at 12:02 +0000, André Draszik wrote:
> > From: André Draszik <andre.draszik at jci.com>
> > 
> > Busybox' getty has code to try to make itself a session leader,
> > whereas util-linux' agetty doesn't. It expects this to happen
> > from outside.
> > When getty is not a session leader, many things don't work on
> > the serial console, e.g. setting the terminal process group,
> > job control doesn't work, etc.
> > 
> > Executing image tests also fails with AssertionErrors, because
> >     Feb  5 16:12:55 qemuarm getty[590]: /dev/ttyAMA1: cannot get
> > controlling tty: Operation not permitted
> >     Feb  5 16:12:55 qemuarm getty[590]: /dev/ttyAMA1: cannot set
> > process group: Inappropriate ioctl for device
> > 
> > Update the start_getty script to invoke getty via the setsid
> > utility if needed, i.e. if /sbin/getty is not busybox getty.
> > 
> > [YOCTO #13058]
> > 
> > Signed-off-by: André Draszik <andre.draszik at jci.com>
> > ---
> >  meta/recipes-core/sysvinit/sysvinit-inittab/start_getty | 9
> > ++++++++-
> >  meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb  | 1 +
> >  2 files changed, 9 insertions(+), 1 deletion(-)
> > 
> > diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> > b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> > index e15ae35f90..ae613f1e54 100644
> > --- a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> > +++ b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> > @@ -13,6 +13,13 @@ active_serial=$(grep "serial" /proc/tty/drivers |
> > cut -d/ -f1 | sed "s/ *$//")
> >  # Rephrase input parameter from ttyS target index (ttyS1, ttyS2,
> > ttyAMA0, etc).
> >  runtime_tty=$(echo $2 | grep -oh '[0-9]')
> >  
> > +# busybox' getty does this itself, util-linux' getty needs extra
> > help
> > +getty="/sbin/getty"
> > +if ! basename $(readlink -f "${getty}") | grep -q busybox \
> > +    && [ -x "/usr/bin/setsid" ] ; then
> > +    getty="/usr/bin/setsid ${getty}"
> > +fi
> 
> The reason I'm reluctant to take changes like this is you just added 3
> fork calls above. This does have a significant effect on boot time on
> slower devices.
> 
> Is there a way we can do a shell string comparison rather than using
> grep? case statement maybe?

I've sent a v2.

Are you aware that there are at least 9 forks in this file for something as
simple as forking a getty?


Cheers,
Andre'

> 
> Cheers,
> 
> Richard
> 
>