1 files changed, 80 insertions, 37 deletions

diff --git a/drm-lease-manager/lease-server.c b/drm-lease-manager/lease-server.c
index e05e8e4..c57316e 100644
--- a/drm-lease-manager/lease-server.c
+++ b/drm-lease-manager/lease-server.c
@@ -32,9 +32,31 @@
 
 #define SOCK_LOCK_SUFFIX ".lock"
 
+/* ACTIVE_CLIENTS
+ * An 'active' client is one that either
+ *  - owns a lease, or
+ *  - is requesting ownership of a lease (which will
+ *    disconnect the current owner if granted)
+ *
+ * There can only be at most one of each kind of client at the same
+ * time. Any other client connections are queued in the
+ * listen() backlog, waiting to be accept()'ed.
+ */
+#define ACTIVE_CLIENTS 2
+
 struct ls_socket {
 	int fd;
+	bool is_server;
+	union {
+		struct ls_server *server;
+		struct ls_client *client;
+	};
+};
+
+struct ls_client {
+	struct ls_socket socket;
 	struct ls_server *serv;
+	bool is_connected;
 };
 
 struct ls_server {
@@ -43,9 +65,7 @@ struct ls_server {
 	int server_socket_lock;
 
 	struct ls_socket listen;
-	struct ls_socket client;
-
-	bool is_client_connected;
+	struct ls_client clients[ACTIVE_CLIENTS];
 };
 
 struct ls {
@@ -55,37 +75,42 @@ struct ls {
 	int nservers;
 };
 
-static bool client_connect(struct ls *ls, struct ls_server *serv)
+static struct ls_client *client_connect(struct ls *ls, struct ls_server *serv)
 {
 	int cfd = accept(serv->listen.fd, NULL, NULL);
 	if (cfd < 0) {
 		DEBUG_LOG("accept failed on %s: %s\n", serv->address.sun_path,
 			  strerror(errno));
-		return false;
+		return NULL;
 	}
 
-	if (serv->is_client_connected) {
-		WARN_LOG("Client already connected on %s\n",
-			 serv->address.sun_path);
+	struct ls_client *client = NULL;
+
+	for (int i = 0; i < ACTIVE_CLIENTS; i++) {
+		if (!serv->clients[i].is_connected) {
+			client = &serv->clients[i];
+			break;
+		}
+	}
+	if (!client) {
 		close(cfd);
-		return false;
+		return NULL;
 	}
 
-	serv->client.fd = cfd;
-	serv->client.serv = serv;
+	client->socket.fd = cfd;
 
 	struct epoll_event ev = {
 	    .events = POLLHUP,
-	    .data.ptr = &serv->client,
+	    .data.ptr = &client->socket,
 	};
 	if (epoll_ctl(ls->epoll_fd, EPOLL_CTL_ADD, cfd, &ev)) {
 		DEBUG_LOG("epoll_ctl add failed: %s\n", strerror(errno));
 		close(cfd);
-		return false;
+		return NULL;
 	}
 
-	serv->is_client_connected = true;
-	return true;
+	client->is_connected = true;
+	return client;
 }
 
 static int create_socket_lock(struct sockaddr_un *addr)
@@ -161,11 +186,18 @@ static bool server_setup(struct ls *ls, struct ls_server *serv,
 		return false;
 	}
 
-	serv->is_client_connected = false;
+	for (int i = 0; i < ACTIVE_CLIENTS; i++) {
+		struct ls_client *client = &serv->clients[i];
+		client->serv = serv;
+		client->socket.client = client;
+	}
+
 	serv->lease_handle = lease_handle;
 	serv->server_socket_lock = socket_lock;
+
 	serv->listen.fd = server_socket;
-	serv->listen.serv = serv;
+	serv->listen.server = serv;
+	serv->listen.is_server = true;
 
 	struct epoll_event ev = {
 	    .events = POLLIN,
@@ -193,7 +225,10 @@ static void server_shutdown(struct ls *ls, struct ls_server *serv)
 
 	epoll_ctl(ls->epoll_fd, EPOLL_CTL_DEL, serv->listen.fd, NULL);
 	close(serv->listen.fd);
-	ls_disconnect_client(ls, serv);
+
+	for (int i = 0; i < ACTIVE_CLIENTS; i++)
+		ls_disconnect_client(ls, &serv->clients[i]);
+
 	close(serv->server_socket_lock);
 }
 
@@ -261,32 +296,37 @@ bool ls_get_request(struct ls *ls, struct ls_req *req)
 		struct ls_socket *sock = ev.data.ptr;
 		assert(sock);
 
-		struct ls_server *server = sock->serv;
-		req->lease_handle = server->lease_handle;
-		req->server = server;
+		struct ls_server *server;
+		struct ls_client *client;
 
-		if (sock == &server->listen) {
+		if (sock->is_server) {
 			if (!(ev.events & POLLIN))
 				continue;
-			if (client_connect(ls, server))
+
+			server = sock->server;
+			client = client_connect(ls, server);
+			if (client)
 				request = LS_REQ_GET_LEASE;
-		} else if (sock == &server->client) {
+		} else {
 			if (!(ev.events & POLLHUP))
 				continue;
+
+			client = sock->client;
+			server = client->serv;
 			request = LS_REQ_RELEASE_LEASE;
-		} else {
-			ERROR_LOG("Internal error: Invalid socket context\n");
-			return false;
 		}
+
+		req->lease_handle = server->lease_handle;
+		req->client = client;
+		req->type = request;
 	}
-	req->type = request;
 	return true;
 }
 
-bool ls_send_fd(struct ls *ls, struct ls_server *serv, int fd)
+bool ls_send_fd(struct ls *ls, struct ls_client *client, int fd)
 {
 	assert(ls);
-	assert(serv);
+	assert(client);
 
 	if (fd < 0)
 		return false;
@@ -312,7 +352,9 @@ bool ls_send_fd(struct ls *ls, struct ls_server *serv, int fd)
 	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
 	*((int *)CMSG_DATA(cmsg)) = fd;
 
-	if (sendmsg(serv->client.fd, &msg, 0) < 0) {
+	struct ls_server *serv = client->serv;
+
+	if (sendmsg(client->socket.fd, &msg, 0) < 0) {
 		DEBUG_LOG("sendmsg failed on %s: %s\n", serv->address.sun_path,
 			  strerror(errno));
 		return false;
@@ -322,14 +364,15 @@ bool ls_send_fd(struct ls *ls, struct ls_server *serv, int fd)
 	return true;
 }
 
-void ls_disconnect_client(struct ls *ls, struct ls_server *serv)
+void ls_disconnect_client(struct ls *ls, struct ls_client *client)
 {
 	assert(ls);
-	assert(serv);
-	if (!serv->is_client_connected)
+	assert(client);
+
+	if (!client->is_connected)
 		return;
 
-	epoll_ctl(ls->epoll_fd, EPOLL_CTL_DEL, serv->client.fd, NULL);
-	close(serv->client.fd);
-	serv->is_client_connected = false;
+	epoll_ctl(ls->epoll_fd, EPOLL_CTL_DEL, client->socket.fd, NULL);
+	close(client->socket.fd);
+	client->is_connected = false;
 }