From 6c1d913ab8614cfafed4c687576bc1bb3dc08208 Mon Sep 17 00:00:00 2001
From: sfc-gh-tclinkenbeard <trevor.clinkenbeard@snowflake.com>
Date: Sun, 11 Jul 2021 21:11:21 -0700
Subject: [PATCH] Prevent masterServer from modifying db

---
 fdbclient/GlobalConfig.actor.h    | 2 +-
 fdbclient/NativeAPI.actor.cpp     | 3 ++-
 fdbserver/WorkerInterface.actor.h | 4 ++--
 fdbserver/masterserver.actor.cpp  | 6 +++---
 fdbserver/worker.actor.cpp        | 4 ++--
 flow/genericactors.actor.h        | 2 +-
 6 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/fdbclient/GlobalConfig.actor.h b/fdbclient/GlobalConfig.actor.h
index 2d63d8de60..444f1ab697 100644
--- a/fdbclient/GlobalConfig.actor.h
+++ b/fdbclient/GlobalConfig.actor.h
@@ -72,7 +72,7 @@ public:
 	// to allow global configuration to run transactions on the latest
 	// database.
 	template <class T>
-	static void create(Database& cx, Reference<AsyncVar<T>> db, const ClientDBInfo* dbInfo) {
+	static void create(Database& cx, Reference<AsyncVar<T> const> db, const ClientDBInfo* dbInfo) {
 		if (g_network->global(INetwork::enGlobalConfig) == nullptr) {
 			auto config = new GlobalConfig{ cx };
 			g_network->setGlobal(INetwork::enGlobalConfig, config);
diff --git a/fdbclient/NativeAPI.actor.cpp b/fdbclient/NativeAPI.actor.cpp
index 5419ae825e..84faf6ffec 100644
--- a/fdbclient/NativeAPI.actor.cpp
+++ b/fdbclient/NativeAPI.actor.cpp
@@ -1756,7 +1756,8 @@ Database Database::createDatabase(Reference<ClusterConnectionFile> connFile,
 	}
 
 	auto database = Database(db);
-	GlobalConfig::create(database, clientInfo, std::addressof(clientInfo->get()));
+	GlobalConfig::create(
+	    database, Reference<AsyncVar<ClientDBInfo> const>(clientInfo), std::addressof(clientInfo->get()));
 	return database;
 }
 
diff --git a/fdbserver/WorkerInterface.actor.h b/fdbserver/WorkerInterface.actor.h
index e642d015dd..3fedfe1c8f 100644
--- a/fdbserver/WorkerInterface.actor.h
+++ b/fdbserver/WorkerInterface.actor.h
@@ -831,7 +831,7 @@ ACTOR Future<Void> traceRole(Role role, UID roleId);
 
 struct ServerDBInfo;
 
-class Database openDBOnServer(Reference<AsyncVar<ServerDBInfo>> const& db,
+class Database openDBOnServer(Reference<AsyncVar<ServerDBInfo> const> const& db,
                               TaskPriority taskID = TaskPriority::DefaultEndpoint,
                               LockAware = LockAware::FALSE,
                               EnableLocalityLoadBalance = EnableLocalityLoadBalance::TRUE);
@@ -879,7 +879,7 @@ ACTOR Future<Void> storageServer(
     Reference<ClusterConnectionFile>
         connFile); // changes pssi->id() to be the recovered ID); // changes pssi->id() to be the recovered ID
 ACTOR Future<Void> masterServer(MasterInterface mi,
-                                Reference<AsyncVar<ServerDBInfo>> db,
+                                Reference<AsyncVar<ServerDBInfo> const> db,
                                 Reference<AsyncVar<Optional<ClusterControllerFullInterface>>> ccInterface,
                                 ServerCoordinators serverCoordinators,
                                 LifetimeToken lifetime,
diff --git a/fdbserver/masterserver.actor.cpp b/fdbserver/masterserver.actor.cpp
index ea93b35f7f..b6bf046991 100644
--- a/fdbserver/masterserver.actor.cpp
+++ b/fdbserver/masterserver.actor.cpp
@@ -228,7 +228,7 @@ struct MasterData : NonCopyable, ReferenceCounted<MasterData> {
 
 	ReusableCoordinatedState cstate;
 	Promise<Void> cstateUpdated;
-	Reference<AsyncVar<ServerDBInfo>> dbInfo;
+	Reference<AsyncVar<ServerDBInfo> const> dbInfo;
 	int64_t registrationCount; // Number of different MasterRegistrationRequests sent to clusterController
 
 	RecoveryState recoveryState;
@@ -255,7 +255,7 @@ struct MasterData : NonCopyable, ReferenceCounted<MasterData> {
 
 	Future<Void> logger;
 
-	MasterData(Reference<AsyncVar<ServerDBInfo>> const& dbInfo,
+	MasterData(Reference<AsyncVar<ServerDBInfo> const> const& dbInfo,
 	           MasterInterface const& myInterface,
 	           ServerCoordinators const& coordinators,
 	           ClusterControllerFullInterface const& clusterController,
@@ -1978,7 +1978,7 @@ ACTOR Future<Void> masterCore(Reference<MasterData> self) {
 }
 
 ACTOR Future<Void> masterServer(MasterInterface mi,
-                                Reference<AsyncVar<ServerDBInfo>> db,
+                                Reference<AsyncVar<ServerDBInfo> const> db,
                                 Reference<AsyncVar<Optional<ClusterControllerFullInterface>>> ccInterface,
                                 ServerCoordinators coordinators,
                                 LifetimeToken lifetime,
diff --git a/fdbserver/worker.actor.cpp b/fdbserver/worker.actor.cpp
index dafcfba2e3..2ff5252320 100644
--- a/fdbserver/worker.actor.cpp
+++ b/fdbserver/worker.actor.cpp
@@ -122,7 +122,7 @@ ACTOR Future<std::vector<Endpoint>> broadcastDBInfoRequest(UpdateServerDBInfoReq
 	return notUpdated;
 }
 
-ACTOR static Future<Void> extractClientInfo(Reference<AsyncVar<ServerDBInfo>> db,
+ACTOR static Future<Void> extractClientInfo(Reference<AsyncVar<ServerDBInfo> const> db,
                                             Reference<AsyncVar<ClientDBInfo>> info) {
 	state std::vector<UID> lastCommitProxyUIDs;
 	state std::vector<CommitProxyInterface> lastCommitProxies;
@@ -136,7 +136,7 @@ ACTOR static Future<Void> extractClientInfo(Reference<AsyncVar<ServerDBInfo>> db
 	}
 }
 
-Database openDBOnServer(Reference<AsyncVar<ServerDBInfo>> const& db,
+Database openDBOnServer(Reference<AsyncVar<ServerDBInfo> const> const& db,
                         TaskPriority taskID,
                         LockAware lockAware,
                         EnableLocalityLoadBalance enableLocalityLoadBalance) {
diff --git a/flow/genericactors.actor.h b/flow/genericactors.actor.h
index d04a0478f8..5cb0344ffb 100644
--- a/flow/genericactors.actor.h
+++ b/flow/genericactors.actor.h
@@ -700,7 +700,7 @@ private:
 // Binds an AsyncTrigger object to an AsyncVar, so when the AsyncVar changes
 // the AsyncTrigger is triggered.
 ACTOR template <class T>
-void forward(Reference<AsyncVar<T>> from, AsyncTrigger* to) {
+void forward(Reference<AsyncVar<T> const> from, AsyncTrigger* to) {
 	loop {
 		wait(from->onChange());
 		to->trigger();