recipes: add functions for generating a rootpasswd

The rootpassword can be set via the
enviroment variable ROOT_PASS either in
the local.conf or on the cmdline
before bitbake.

Fixes: partly SYS#518

recipes-apps/images/image-passwd.inc

@@ -0,0 +1,16 @@
+DEPENDS += "openssl-native"
+
+rootpasswd = "${@d.getVar('ROOT_PASS', True) or ""}"
+
+ROOTFS_POSTPROCESS_COMMAND += "set_root_passwd;"
+
+set_root_passwd() {
+   if [ -n "${rootpasswd}" ]; then
+       HASHED_PASS=`openssl passwd -1 ${rootpasswd}`
+       if [ -n "${HASHED_PASS}" ]; then
+           sed -e "s%^root:[^:]*:%root:${HASHED_PASS}:%" \
+               -i ${IMAGE_ROOTFS}/etc/shadow
+           echo "Generated new root-passwd"
+       fi
+  fi
+}