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

["André Draszik" <git@andred.net>]

From: André Draszik <andre.draszik@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@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
 				fi
 				break
 			fi
diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb b/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
index 8585a418ab..bfd890d924 100644
--- a/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
+++ b/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
@@ -20,6 +20,7 @@ do_install() {
     install -m 0644 ${WORKDIR}/inittab ${D}${sysconfdir}/inittab
     install -d ${D}${base_bindir}
     install -m 0755 ${WORKDIR}/start_getty ${D}${base_bindir}/start_getty
+    sed -e 's,/usr/bin,${bindir},g' -i ${D}${base_bindir}/start_getty
 
     set -x
     tmp="${SERIAL_CONSOLES}"
-- 
2.20.1