[gnome-continuous-yocto/gnomeostree-3.28-rocko: 6080/8267] start_getty: Over added SERIAL_CONSOLE cause error in userspace log

[Emmanuele Bassi <ebassi src gnome org>]

commit 65dfeb248ba0209fb6b6966e28cb28f1b063fdda
Author: Choong YinThong <yin thong choong intel com>
Date:   Thu Apr 13 17:26:39 2017 -0700

    start_getty: Over added SERIAL_CONSOLE cause error in userspace log
    
    Error log will be logged into /var/log/message.
    Added in more condition checking on the script. Check
    /proc/tty/drivers and /proc/tty/driver/*
    file system to retrieve active targeted serial.
    Only establish getty with active serial in runtime.
    
    [YOCTO #10844]
    
    Reviewed-by: Saul Wold <sgw linux intel com>
    (From OE-Core rev: ac0e9541fe93e866e42914f65a0516b993f0cffe)
    
    Signed-off-by: Choong YinThong <yin thong choong intel com>
    Signed-off-by: Ross Burton <ross burton intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 .../sysvinit/sysvinit-inittab/start_getty          |   38 +++++++++++++++++--
 1 files changed, 34 insertions(+), 4 deletions(-)
---
diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty 
b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
index e3d052a..31b4413 100644
--- a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
+++ b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
@@ -1,5 +1,35 @@
 #!/bin/sh
-if [ -c /dev/$2 ]
-then 
-       /sbin/getty -L $1 $2 $3
-fi
+####################################################################################
+# This script is use to automatic start serial console once power up.
+# Script enhancement has been done base on Bug YOCTO 10844.
+# Configuration can be done in meta/conf/machine/*.conf variable SERIAL_CONSOLES.
+# Most of the information is retrieve from /proc virtual filesystem which
+# contain all the runtime system information (eg. system memory, device mount, etc).
+####################################################################################
+
+# Get active serial filename.
+active_serial=$(grep "serial" /proc/tty/drivers | grep -oh "^\s*\S*")
+
+# Re-phrase input parameter from ttyS target index (ttyS1, ttyS2, ttyAMA0, etc).
+runtime_tty=$(echo $2 | grep -oh '[0-9]')
+
+for line in $active_serial; do
+       # File is availability, file content current active serial target index.
+       if [ -e /proc/tty/driver/$line ]
+        then
+               # File content a lot of unknown serial. We use -v to remove all unmatch and get left off.
+               # Tail use to avoid 1st line included into the filter because 1st line is file description.
+               activetty=$(grep -v "unknown" /proc/tty/driver/$line | tail -n +2 | grep -oh "^\s*\S*[0-9]")
+               for active in $activetty; do
+                       # Check if both index is match then proceed to enable the serial console.
+                       if [ $active -eq $runtime_tty ] 
+                       then
+                               if [ -c /dev/$2 ]
+                               then
+                                   /sbin/getty -L $1 $2 $3
+                               fi
+                               break
+                       fi
+               done
+       fi
+done