B #212: Fix chown command on FreeBSD

+ fix error when CONTEXT_FILE is empty (not likely)
+ fix other warning/error messages shown in the log
+ make the script compliant with shellshock

Signed-off-by: Petr Ospalý <pospaly@opennebula.io>

Author: ospalax

src/etc/one-context.d/loc-16-gen-env

@@ -17,33 +17,36 @@
 #--------------------------------------------------------------------------- #
 
 ENV_FILE=/var/run/one-context/one_env
-MOUNT_DIR=${MOUNT_DIR:-/mnt}
-TOKENTXT=$(cat "${MOUNT_DIR}/token.txt")
+MOUNT_DIR="${MOUNT_DIR:-/mnt}"
+TOKEN_FILE="${MOUNT_DIR}/token.txt"
 
 if [ -n "$ONEGATE_TOKEN" ]; then
     TOKENTXT="$ONEGATE_TOKEN"
+elif [ -f "$TOKEN_FILE" ]; then
+    TOKENTXT=$(cat "$TOKEN_FILE")
 fi
 
 umask 0377
-echo "export TOKENTXT=\"$TOKENTXT\"" > $ENV_FILE
-echo "export VMID=\"$VMID\"" >> $ENV_FILE
-echo "export ONEGATE_ENDPOINT=\"$ONEGATE_ENDPOINT\"" >> $ENV_FILE
+echo "export TOKENTXT=\"$TOKENTXT\"" > "$ENV_FILE"
+echo "export VMID=\"$VMID\"" >> "$ENV_FILE"
+echo "export ONEGATE_ENDPOINT=\"$ONEGATE_ENDPOINT\"" >> "$ENV_FILE"
 
 function export_rc_vars
 {
-  if [ -f $1 ] ; then
-    ONE_VARS=$(cat $1 | egrep -e '^[a-zA-Z\-\_0-9]*=' | sed 's/=.*$//')
+  if [ -n "$1" ] && [ -f "$1" ] ; then
+    ONE_VARS=$(grep -E -e '^[a-zA-Z\-\_0-9]*=' "$1" | sed 's/=.*$//')
 
-    . $1
+    # shellcheck disable=SC1090
+    . "$1"
 
     for v in $ONE_VARS; do
-        echo "export $v=\"${!v}\"" >> $ENV_FILE
+        echo "export $v=\"${!v}\"" >> "$ENV_FILE"
     done
   fi
 }
 
-export_rc_vars ${CONTEXT_FILE}
+export_rc_vars "${CONTEXT_FILE}"
 
-chown root:root $ENV_FILE
-chmod 0400 $ENV_FILE
+chown "root:$(id -gn root)" "$ENV_FILE"
+chmod 0400 "$ENV_FILE"