Add lease request and release protocol

Explicitly request / release leases instead of implicitly
by opening and closing the connection.  This will allow the
lease manager to take different action when a client
shuts down gracefully vs when it crashes, holding a lease.

Bug-AGL: SPEC-3862

Signed-off-by: Damian Hobson-Garcia <dhobsong@igel.co.jp>
Change-Id: Ibc68bee855ce18e56eb6f57e5ad1743248320013

7 files changed, 193 insertions, 30 deletions

diff --git a/common/dlm-protocol.c b/common/dlm-protocol.c
new file mode 100644
index 0000000..4fc87b2
--- /dev/null
+++ b/common/dlm-protocol.c
@@ -0,0 +1,66 @@
+/* Copyright 2020-2021 IGEL Co., Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dlm-protocol.h"
+
+#include <errno.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+bool receive_dlm_client_request(int socket, struct dlm_client_request *request)
+{
+
+	ssize_t len;
+	struct iovec iov = {
+	    .iov_base = request,
+	    .iov_len = sizeof(*request),
+	};
+	struct msghdr msg = {
+	    .msg_iov = &iov,
+	    .msg_iovlen = 1,
+	};
+
+	while ((len = recvmsg(socket, &msg, 0)) < 0) {
+		if (errno != EINTR)
+			return false;
+	}
+
+	if (len != sizeof(*request)) {
+		errno = EPROTO;
+		return false;
+	}
+	return true;
+}
+
+bool send_dlm_client_request(int socket, struct dlm_client_request *request)
+{
+	struct iovec iov = {
+	    .iov_base = request,
+	    .iov_len = sizeof(*request),
+	};
+
+	struct msghdr msg = {
+	    .msg_iov = &iov,
+	    .msg_iovlen = 1,
+	};
+
+	while (sendmsg(socket, &msg, 0) < 1) {
+		if (errno != EINTR)
+			return false;
+	}
+	return true;
+}
diff --git a/common/dlm-protocol.h b/common/dlm-protocol.h
new file mode 100644
index 0000000..44785e5
--- /dev/null
+++ b/common/dlm-protocol.h
@@ -0,0 +1,32 @@
+/* Copyright 2020-2021 IGEL Co., Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef DLM_PROTOCOL_H
+#define DLM_PROTOCOL_H
+
+#include <stdbool.h>
+
+enum dlm_opcode {
+	DLM_GET_LEASE,
+	DLM_RELEASE_LEASE,
+};
+
+struct dlm_client_request {
+	enum dlm_opcode opcode;
+};
+
+bool receive_dlm_client_request(int socket, struct dlm_client_request *request);
+bool send_dlm_client_request(int socket, struct dlm_client_request *request);
+#endif
diff --git a/common/meson.build b/common/meson.build
index e465fa5..663c1ce 100644
--- a/common/meson.build
+++ b/common/meson.build
@@ -1,4 +1,5 @@
 libdlmcommon_sources = [
+        'dlm-protocol.c',
         'socket-path.c',
         'log.c'
 ]
diff --git a/drm-lease-manager/lease-server.c b/drm-lease-manager/lease-server.c
index c57316e..ac4dd01 100644
--- a/drm-lease-manager/lease-server.c
+++ b/drm-lease-manager/lease-server.c
@@ -14,6 +14,8 @@
  */
 
 #include "lease-server.h"
+
+#include "dlm-protocol.h"
 #include "log.h"
 #include "socket-path.h"
 
@@ -75,13 +77,13 @@ struct ls {
 	int nservers;
 };
 
-static struct ls_client *client_connect(struct ls *ls, struct ls_server *serv)
+static void 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 NULL;
+		return;
 	}
 
 	struct ls_client *client = NULL;
@@ -94,23 +96,44 @@ static struct ls_client *client_connect(struct ls *ls, struct ls_server *serv)
 	}
 	if (!client) {
 		close(cfd);
-		return NULL;
+		return;
 	}
 
 	client->socket.fd = cfd;
 
 	struct epoll_event ev = {
-	    .events = POLLHUP,
+	    .events = POLLIN,
 	    .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 NULL;
+		return;
 	}
 
 	client->is_connected = true;
-	return client;
+}
+
+static int parse_client_request(struct ls_socket *client)
+{
+	int ret = -1;
+	struct dlm_client_request hdr;
+	if (!receive_dlm_client_request(client->fd, &hdr))
+		return ret;
+
+	switch (hdr.opcode) {
+	case DLM_GET_LEASE:
+		ret = LS_REQ_GET_LEASE;
+		break;
+	case DLM_RELEASE_LEASE:
+		ret = LS_REQ_RELEASE_LEASE;
+		break;
+	default:
+		ERROR_LOG("Unexpected client request received\n");
+		break;
+	};
+
+	return ret;
 }
 
 static int create_socket_lock(struct sockaddr_un *addr)
@@ -165,7 +188,7 @@ static bool server_setup(struct ls *ls, struct ls_server *serv,
 
 	address->sun_family = AF_UNIX;
 
-	int server_socket = socket(PF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
+	int server_socket = socket(PF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK, 0);
 	if (server_socket < 0) {
 		DEBUG_LOG("Socket creation failed: %s\n", strerror(errno));
 		return false;
@@ -296,25 +319,20 @@ bool ls_get_request(struct ls *ls, struct ls_req *req)
 		struct ls_socket *sock = ev.data.ptr;
 		assert(sock);
 
-		struct ls_server *server;
-		struct ls_client *client;
-
 		if (sock->is_server) {
-			if (!(ev.events & POLLIN))
-				continue;
+			if (ev.events & POLLIN)
+				client_connect(ls, sock->server);
+			continue;
+		}
 
-			server = sock->server;
-			client = client_connect(ls, server);
-			if (client)
-				request = LS_REQ_GET_LEASE;
-		} else {
-			if (!(ev.events & POLLHUP))
-				continue;
+		if (ev.events & POLLIN)
+			request = parse_client_request(sock);
 
-			client = sock->client;
-			server = client->serv;
+		if (request < 0 && (ev.events & POLLHUP))
 			request = LS_REQ_RELEASE_LEASE;
-		}
+
+		struct ls_client *client = sock->client;
+		struct ls_server *server = client->serv;
 
 		req->lease_handle = server->lease_handle;
 		req->client = client;
diff --git a/drm-lease-manager/test/test-socket-client.c b/drm-lease-manager/test/test-socket-client.c
index 260437a..9d191ff 100644
--- a/drm-lease-manager/test/test-socket-client.c
+++ b/drm-lease-manager/test/test-socket-client.c
@@ -28,6 +28,7 @@
 #include <sys/un.h>
 #include <unistd.h>
 
+#include "dlm-protocol.h"
 #include "socket-path.h"
 
 #define DEFAULT_RECV_TIMEOUT (100) // timeout in ms to receive data from server
@@ -39,6 +40,14 @@ struct client_state {
 	struct test_config *config;
 };
 
+static void send_lease_request(int socket, enum dlm_opcode opcode)
+{
+	struct dlm_client_request req = {
+	    .opcode = opcode,
+	};
+	send_dlm_client_request(socket, &req);
+}
+
 static void client_gst_socket_status(int socket_fd, struct test_config *config)
 {
 
@@ -104,7 +113,7 @@ static void *test_client_thread(void *arg)
 	    sockaddr_set_lease_server_path(&address, config->lease->name),
 	    true);
 
-	int client = socket(PF_UNIX, SOCK_STREAM, 0);
+	int client = socket(PF_UNIX, SOCK_SEQPACKET, 0);
 	ck_assert_int_ge(client, 0);
 
 	int ret;
@@ -115,6 +124,8 @@ static void *test_client_thread(void *arg)
 		return NULL;
 	}
 
+	send_lease_request(client, DLM_GET_LEASE);
+
 	if (!config->recv_timeout)
 		config->recv_timeout = DEFAULT_RECV_TIMEOUT;
 
@@ -125,6 +136,7 @@ static void *test_client_thread(void *arg)
 	}
 
 	cstate->socket_fd = client;
+	send_lease_request(client, DLM_RELEASE_LEASE);
 
 	return NULL;
 }
diff --git a/libdlmclient/dlmclient.c b/libdlmclient/dlmclient.c
index 32493d3..03c08a8 100644
--- a/libdlmclient/dlmclient.c
+++ b/libdlmclient/dlmclient.c
@@ -14,6 +14,8 @@
  */
 
 #include "dlmclient.h"
+
+#include "dlm-protocol.h"
 #include "log.h"
 #include "socket-path.h"
 
@@ -46,7 +48,7 @@ static bool lease_connect(struct dlm_lease *lease, const char *name)
 	if (!sockaddr_set_lease_server_path(&sa, name))
 		return false;
 
-	int dlm_server_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+	int dlm_server_sock = socket(AF_UNIX, SOCK_SEQPACKET, 0);
 	if (dlm_server_sock < 0) {
 		DEBUG_LOG("Socket creation failed: %s\n", strerror(errno));
 		return false;
@@ -65,6 +67,19 @@ static bool lease_connect(struct dlm_lease *lease, const char *name)
 	return true;
 }
 
+static bool lease_send_request(struct dlm_lease *lease, enum dlm_opcode opcode)
+{
+	struct dlm_client_request request = {
+	    .opcode = opcode,
+	};
+
+	if (!send_dlm_client_request(lease->dlm_server_sock, &request)) {
+		DEBUG_LOG("Socket data send error: %s\n", strerror(errno));
+		return false;
+	}
+	return true;
+}
+
 static bool lease_recv_fd(struct dlm_lease *lease)
 {
 	char ctrl_buf[CMSG_SPACE(sizeof(int))] = {0};
@@ -131,6 +146,7 @@ static bool lease_recv_fd(struct dlm_lease *lease)
 
 struct dlm_lease *dlm_get_lease(const char *name)
 {
+	int saved_errno;
 	struct dlm_lease *lease = calloc(1, sizeof(struct dlm_lease));
 	if (!lease) {
 		DEBUG_LOG("can't allocate memory : %s\n", strerror(errno));
@@ -142,13 +158,19 @@ struct dlm_lease *dlm_get_lease(const char *name)
 		return NULL;
 	}
 
-	if (!lease_recv_fd(lease)) {
-		close(lease->dlm_server_sock);
-		free(lease);
-		return NULL;
-	}
+	if (!lease_send_request(lease, DLM_GET_LEASE))
+		goto err;
+
+	if (!lease_recv_fd(lease))
+		goto err;
 
 	return lease;
+
+err:
+	saved_errno = errno;
+	dlm_release_lease(lease);
+	errno = saved_errno;
+	return NULL;
 }
 
 void dlm_release_lease(struct dlm_lease *lease)
@@ -156,6 +178,7 @@ void dlm_release_lease(struct dlm_lease *lease)
 	if (!lease)
 		return;
 
+	lease_send_request(lease, DLM_RELEASE_LEASE);
 	close(lease->lease_fd);
 	close(lease->dlm_server_sock);
 	free(lease);
diff --git a/libdlmclient/test/test-socket-server.c b/libdlmclient/test/test-socket-server.c
index 281aaf7..6aaa4e4 100644
--- a/libdlmclient/test/test-socket-server.c
+++ b/libdlmclient/test/test-socket-server.c
@@ -25,6 +25,7 @@
 #include <sys/un.h>
 #include <unistd.h>
 
+#include "dlm-protocol.h"
 #include "socket-path.h"
 #include "test-helpers.h"
 
@@ -56,6 +57,13 @@ static void send_fd_list_over_socket(int socket, int nfds, int *fds)
 	free(buf);
 }
 
+static void expect_client_command(int socket, enum dlm_opcode opcode)
+{
+	struct dlm_client_request req;
+	ck_assert_int_eq(receive_dlm_client_request(socket, &req), true);
+	ck_assert_int_eq(req.opcode, opcode);
+}
+
 struct server_state {
 	pthread_t tid;
 	pthread_mutex_t lock;
@@ -77,7 +85,7 @@ static void *test_server_thread(void *arg)
 	ck_assert_int_eq(
 	    sockaddr_set_lease_server_path(&address, config->lease_name), true);
 
-	int server = socket(PF_UNIX, SOCK_STREAM, 0);
+	int server = socket(PF_UNIX, SOCK_SEQPACKET, 0);
 	ck_assert_int_ge(server, 0);
 
 	unlink(address.sun_path);
@@ -102,6 +110,8 @@ static void *test_server_thread(void *arg)
 		return NULL;
 	}
 
+	expect_client_command(client, DLM_GET_LEASE);
+
 	if (config->send_no_data)
 		goto done;
 
@@ -120,6 +130,7 @@ static void *test_server_thread(void *arg)
 		config->fds[i] = get_dummy_fd();
 
 	send_fd_list_over_socket(client, config->nfds, config->fds);
+	expect_client_command(client, DLM_RELEASE_LEASE);
 done:
 	close(client);
 	close(server);