[OE-core] [PATCH v2] sysvinit-inittab: support non-busybox-getty on serial consoles

[André Draszik]

On Fri, 2019-02-08 at 18:46 +0100, Andreas Oberritter wrote:
> Hi André,
> 
> On Fri,  8 Feb 2019 16:48:32 +0000
> André Draszik <git at andred.net> 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>
> > 
> > ---
> > v2: fork fewer processes
> > ---
> >  .../sysvinit/sysvinit-inittab/start_getty          | 14 +++++++++++++-
> >  .../sysvinit/sysvinit-inittab_2.88dsf.bb           |  1 +
> >  2 files changed, 14 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..d3ebb84e18 100644
> > --- a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> > +++ b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> > @@ -13,6 +13,18 @@ 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' agetty needs extra help
> > +getty="/sbin/getty"
> > +case $(readlink -f "${getty}") in
> > +    */busybox*)
> > +        ;;
> > +    *)
> > +        if [ -x "/usr/bin/setsid" ] ; then
> > +            getty="/usr/bin/setsid ${getty}"
> > +        fi
> > +        ;;
> > +esac
> > +
> >  # Backup $IFS.
> >  DEFAULT_IFS=$IFS
> >  # Customize Internal Field Separator.
> > @@ -31,7 +43,7 @@ for line in $active_serial; do
> >  			then
> >  				if [ -c /dev/$2 ]
> >  				then
> > -				    /sbin/getty -L $1 $2 $3
> > +				    eval ${getty} -L $1 $2 $3
> 
> I think using eval isn't necessary.

I didn't investigate why, but it was necessary in this version for whatever
reason - v3 got rid of it now by adding another variable.

Cheers,
Andre'

> 
> Best regards,
> Andreas