[Rework] Redis_pool: fix issues found

src/libserver/redis_pool.cxx

@@ -69,20 +69,17 @@ struct redis_pool_connection {
 	gchar tag[MEMPOOL_UID_LEN];
 
 	auto schedule_timeout() -> void;
-
 	~redis_pool_connection();
 
 	explicit redis_pool_connection(redis_pool *_pool,
 								   redis_pool_elt *_elt,
-								   const char *db,
-								   const char *password,
+								   const std::string &db,
+								   const std::string &password,
 								   struct redisAsyncContext *_ctx);
 
 private:
 	static auto redis_conn_timeout_cb(EV_P_ ev_timer *w, int revents) -> void;
-
 	static auto redis_quit_cb(redisAsyncContext *c, void *r, void *priv) -> void;
-
 	static auto redis_on_disconnect(const struct redisAsyncContext *ac, int status) -> auto;
 };
 
@@ -109,10 +106,17 @@ public:
 	explicit redis_pool_elt(redis_pool *_pool,
 							const gchar *_db, const gchar *_password,
 							const char *_ip, int _port)
-			: pool(_pool), ip(_ip), db(_db), password(_password), port(_port),
+			: pool(_pool), ip(_ip), port(_port),
 			  key(redis_pool_elt::make_key(_db, _password, _ip, _port))
 	{
 		is_unix = ip[0] == '.' || ip[0] == '/';
+
+		if (_db) {
+			db = _db;
+		}
+		if (_password) {
+			password = _password;
+		}
 	}
 
 	auto new_connection() -> redisAsyncContext *;
@@ -157,6 +161,10 @@ public:
 		return active.size();
 	}
 
+	~redis_pool_elt() {
+		rspamd_explicit_memzero(password.data(), password.size());
+	}
+
 private:
 	auto redis_async_new() -> redisAsyncContext *
 	{
@@ -186,9 +194,9 @@ class redis_pool {
 	static constexpr const unsigned default_max_conns = 100;
 
 	/* We want to have references integrity */
-	robin_hood::unordered_node_map<redis_pool_key_t, redis_pool_elt> elts_by_key;
 	robin_hood::unordered_flat_map<redisAsyncContext *,
 			redis_pool_connection *> conns_by_ctx;
+	robin_hood::unordered_node_map<redis_pool_key_t, redis_pool_elt> elts_by_key;
 public:
 	double timeout = default_timeout;
 	unsigned max_conns = default_max_conns;
@@ -363,8 +371,8 @@ redis_pool_connection::schedule_timeout() -> void
 
 redis_pool_connection::redis_pool_connection(redis_pool *_pool,
 											 redis_pool_elt *_elt,
-											 const char *db,
-											 const char *password,
+											 const std::string &db,
+											 const std::string &password,
 											 struct redisAsyncContext *_ctx)
 		: ctx(_ctx), elt(_elt), pool(_pool)
 {
@@ -378,13 +386,13 @@ redis_pool_connection::redis_pool_connection(redis_pool *_pool,
 	redisLibevAttach(pool->event_loop, ctx);
 	redisAsyncSetDisconnectCallback(ctx, redis_pool_connection::redis_on_disconnect);
 
-	if (password) {
-		redisAsyncCommand(ctx, NULL, NULL,
-				"AUTH %s", password);
+	if (!password.empty()) {
+		redisAsyncCommand(ctx, nullptr, nullptr,
+				"AUTH %s", password.c_str());
 	}
-	if (db) {
-		redisAsyncCommand(ctx, NULL, NULL,
-				"SELECT %s", db);
+	if (!db.empty()) {
+		redisAsyncCommand(ctx, nullptr, nullptr,
+				"SELECT %s", db.c_str());
 	}
 }
 
@@ -392,7 +400,8 @@ auto
 redis_pool_elt::new_connection() -> redisAsyncContext *
 {
 	if (!inactive.empty()) {
-		auto &&conn = std::move(inactive.back());
+		decltype(inactive)::value_type conn;
+		conn.swap(inactive.back());
 		inactive.pop_back();
 
 		g_assert (conn->state != RSPAMD_REDIS_POOL_CONN_ACTIVE);
@@ -421,6 +430,8 @@ redis_pool_elt::new_connection() -> redisAsyncContext *
 						ip.c_str(), port, conn->ctx);
 				active.emplace_front(std::move(conn));
 				active.front()->elt_pos = active.begin();
+
+				return active.front()->ctx;
 			}
 		}
 		else {
@@ -463,8 +474,9 @@ redis_pool::new_connection(const gchar *db, const gchar *password,
 	}
 	else {
 		/* Need to create a pool */
-		auto nelt = elts_by_key.emplace(key,
-				redis_pool_elt{this, db, password, ip, port});
+		auto nelt = elts_by_key.emplace(std::piecewise_construct,
+				std::forward_as_tuple(key),
+				std::forward_as_tuple(this, db, password, ip, port));
 
 		return nelt.first->second.new_connection();
 	}
@@ -481,7 +493,6 @@ auto redis_pool::release_connection(redisAsyncContext *ctx,
 		if (ctx->err != REDIS_OK) {
 			/* We need to terminate connection forcefully */
 			msg_debug_rpool ("closed connection %p due to an error", conn->ctx);
-			conn->elt->release_active(conn);
 		}
 		else {
 			if (how == RSPAMD_REDIS_RELEASE_DEFAULT) {
@@ -492,11 +503,12 @@ auto redis_pool::release_connection(redisAsyncContext *ctx,
 					conn->elt->move_to_inactive(conn);
 					conn->schedule_timeout();
 					msg_debug_rpool("mark connection %p inactive", conn->ctx);
+
+					return;
 				}
 				else {
 					msg_debug_rpool("closed connection %p due to callbacks left",
 							conn->ctx);
-					conn->elt->release_active(conn);
 				}
 			}
 			else {
@@ -508,8 +520,6 @@ auto redis_pool::release_connection(redisAsyncContext *ctx,
 					msg_debug_rpool("closed connection %p due to explicit termination",
 							conn->ctx);
 				}
-
-				conn->elt->release_active(conn);
 			}
 		}