Add support for platform topology configuration service (#12066)

* Add support for platform topology configuration service

    This service invokes the platform plugin for platform specific topology
    configuration.
    The path for platform plugin script is:
    /usr/share/sonic/device/$PLATFORM/plugins/config-topology.sh
    If the platform plugin is not available, this service does nothing.

Signed-off-by: anamehra <anamehra@cisco.com>

files/build_templates/config-setup.service.j2

@@ -2,6 +2,8 @@
 Description=Config initialization and migration service
 After=rc-local.service
 After=database.service
+After=config-topology.service
+Requires=config-topology.service
 Requires=database.service
 {% if sonic_asic_platform == 'mellanox' -%}
 Requires=hw-management.service

files/build_templates/sonic_debian_extension.j2

@@ -566,6 +566,11 @@ echo "topology.service" | sudo tee -a $GENERATED_SERVICE_FILE
 sudo cp $IMAGE_CONFIGS/topology/topology.sh $FILESYSTEM_ROOT/usr/bin
 {%- endif %}
 
+# Copy platform topology configuration scripts
+sudo cp $IMAGE_CONFIGS/config-topology/config-topology.service $FILESYSTEM_ROOT_USR_LIB_SYSTEMD_SYSTEM
+echo "config-topology.service" | sudo tee -a $GENERATED_SERVICE_FILE
+sudo cp $IMAGE_CONFIGS/config-topology/config-topology.sh $FILESYSTEM_ROOT/usr/bin
+
 # Copy updategraph script and service file
 j2 files/build_templates/updategraph.service.j2 | sudo tee $FILESYSTEM_ROOT_USR_LIB_SYSTEMD_SYSTEM/updategraph.service
 sudo cp $IMAGE_CONFIGS/updategraph/updategraph $FILESYSTEM_ROOT/usr/bin/

files/image_config/config-topology/config-topology.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=Platform topology configuration service
+After=database.service
+After=database-chassis.service
+Requires=database.service
+Requires=database-chassis.service
+Before=config-setup.service
+
+[Service]
+Type=oneshot
+User=root
+RemainAfterExit=yes
+ExecStart=/usr/bin/config-topology.sh start
+ExecStop=/usr/bin/config-topology.sh stop
+
+[Install]
+WantedBy=multi-user.target
+

files/image_config/config-topology/config-topology.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+# This script is invoked by config-topology.service.
+# This script invokes platform plugin script if present
+# which could be used for platform specific topology configuration
+#
+start() {
+    PLATFORM=`sonic-cfggen -H -v DEVICE_METADATA.localhost.platform`
+    #Path to platform topology script
+    TOPOLOGY_SCRIPT="/usr/share/sonic/device/$PLATFORM/plugins/config-topology.sh"
+    #if topology script file not present, do nothing and return 0
+    [ ! -f $TOPOLOGY_SCRIPT ] && exit 0
+    $TOPOLOGY_SCRIPT start
+}
+
+stop() {
+    PLATFORM=`sonic-cfggen -H -v DEVICE_METADATA.localhost.platform`
+    #Path to platform topology script
+    TOPOLOGY_SCRIPT="/usr/share/sonic/device/$PLATFORM/plugins/config-topology.sh"
+    #if topology script file not present, do nothing and return 0
+    [ ! -f $TOPOLOGY_SCRIPT ] && exit 0
+    $TOPOLOGY_SCRIPT stop
+}
+
+# read SONiC immutable variables
+[ -f /etc/sonic/sonic-environment ] && . /etc/sonic/sonic-environment
+
+case "$1" in
+    start|stop)
+        $1
+        ;;
+    *)
+        echo "Usage: $0 {start|stop}"
+        ;;
+esac

src/systemd-sonic-generator/systemd-sonic-generator.c

@@ -104,7 +104,23 @@ static int get_target_lines(char* unit_file, char* target_lines[]) {
 static bool is_multi_instance_service(char *service_name){
     int i;
     for(i=0; i < num_multi_inst; i++){
-        if (strstr(service_name, multi_instance_services[i]) != NULL) {
+        /*
+         * The service name may contain @.service or .service. Remove these
+         * postfixes and extract service name. Compare service name for absolute
+         * match in multi_instance_services[].
+         * This is to prevent services like database-chassis and systemd-timesyncd marked
+         * as multi instance services as they contain strings 'database' and 'syncd' respectively
+         * which are multi instance services in multi_instance_services[].
+         */
+        char *saveptr;
+        char *token = strtok_r(service_name, "@", &saveptr);
+        if (token) {
+            if (strstr(token, ".service") != NULL) {
+                /* If we are here, service_name did not have '@' delimiter but contains '.service' */
+                token = strtok_r(service_name, ".", &saveptr);
+            }
+        }
+        if (strncmp(service_name, multi_instance_services[i], strlen(service_name)) == 0) {
             return true;
         }
     }