[shell] Clean up shutdown handling.

- Revert erroneous shutdown protection in Server.cpp
- Add app-level shutdown protection in cmd_server.cpp

examples/shell/shell_common/cmd_server.cpp

@@ -42,6 +42,7 @@ bool lowPowerClusterSleep()
 static chip::Shell::Engine sShellServerSubcommands;
 static uint16_t sServerPortOperational   = CHIP_PORT;
 static uint16_t sServerPortCommissioning = CHIP_UDC_PORT;
+static bool sServerEnabled               = false;
 
 static CHIP_ERROR CmdAppServerHelp(int argc, char ** argv)
 {
@@ -57,12 +58,17 @@ static CHIP_ERROR CmdAppServerStart(int argc, char ** argv)
     // Initialize device attestation config
     SetDeviceAttestationCredentialsProvider(Examples::GetExampleDACProvider());
 
+    sServerEnabled = true;
+
     return CHIP_NO_ERROR;
 }
 
 static CHIP_ERROR CmdAppServerStop(int argc, char ** argv)
 {
+    if (sServerEnabled == false)
+        return CHIP_NO_ERROR;
     chip::Server::GetInstance().Shutdown();
+    sServerEnabled = false;
     return CHIP_NO_ERROR;
 }
 

src/app/server/Server.cpp

@@ -233,8 +233,7 @@ CHIP_ERROR Server::Init(AppDelegate * delegate, uint16_t secureServicePort, uint
                                                     &mSessions, &mFabrics, &mSessionIDAllocator);
     SuccessOrExit(err);
 
-    err    = mCASESessionManager.Init();
-    mState = ServerState::Enabled;
+    err = mCASESessionManager.Init();
 
 exit:
     if (err != CHIP_NO_ERROR)
@@ -250,18 +249,13 @@ CHIP_ERROR Server::Init(AppDelegate * delegate, uint16_t secureServicePort, uint
 
 void Server::Shutdown()
 {
-    if (mState == ServerState::Disabled)
-        return;
-
     chip::Dnssd::ServiceAdvertiser::Instance().Shutdown();
     chip::app::InteractionModelEngine::GetInstance()->Shutdown();
     mExchangeMgr.Shutdown();
     mSessions.Shutdown();
     mTransports.Close();
     mCommissioningWindowManager.Shutdown();
     chip::Platform::MemoryShutdown();
-
-    mState = ServerState::Disabled;
 }
 
 #if CHIP_DEVICE_CONFIG_ENABLE_COMMISSIONER_DISCOVERY_CLIENT