init: add class_restart

Bug: 34093663
Test: hwservicemanager `onrestart class_restart hal` works
Change-Id: Ie1e4daab2b7b4c6c714d4e3d05afa2d86d6233df
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 32e9ef6..95f1aa0 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -148,6 +148,12 @@
     return 0;
 }
 
+static int do_class_restart(const std::vector<std::string>& args) {
+    ServiceManager::GetInstance().
+        ForEachServiceInClass(args[1], [] (Service* s) { s->Restart(); });
+    return 0;
+}
+
 static int do_domainname(const std::vector<std::string>& args) {
     return write_file("/proc/sys/kernel/domainname", args[1].c_str()) ? 0 : 1;
 }
@@ -897,6 +903,7 @@
         {"chmod",                   {2,     2,    do_chmod}},
         {"chown",                   {2,     3,    do_chown}},
         {"class_reset",             {1,     1,    do_class_reset}},
+        {"class_restart",           {1,     1,    do_class_restart}},
         {"class_start",             {1,     1,    do_class_start}},
         {"class_stop",              {1,     1,    do_class_stop}},
         {"copy",                    {2,     2,    do_copy}},