1 files changed, 170 insertions, 0 deletions
diff --git a/libdlmclient/dlmclient.c b/libdlmclient/dlmclient.c
new file mode 100644
index 0000000..32493d3
--- /dev/null
+++ b/libdlmclient/dlmclient.c
@@ -0,0 +1,170 @@
+/* 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 "dlmclient.h"
+#include "log.h"
+#include "socket-path.h"
+
+#include <assert.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+void dlm_enable_debug_log(bool enable)
+{
+	dlm_log_enable_debug(enable);
+}
+
+struct dlm_lease {
+	int dlm_server_sock;
+	int lease_fd;
+};
+
+static bool lease_connect(struct dlm_lease *lease, const char *name)
+{
+	struct sockaddr_un sa = {
+	    .sun_family = AF_UNIX,
+	};
+
+	if (!sockaddr_set_lease_server_path(&sa, name))
+		return false;
+
+	int dlm_server_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (dlm_server_sock < 0) {
+		DEBUG_LOG("Socket creation failed: %s\n", strerror(errno));
+		return false;
+	}
+
+	while (connect(dlm_server_sock, (struct sockaddr *)&sa,
+		       sizeof(struct sockaddr_un)) == -1) {
+		if (errno == EINTR)
+			continue;
+		DEBUG_LOG("Cannot connect to %s: %s\n", sa.sun_path,
+			  strerror(errno));
+		close(dlm_server_sock);
+		return false;
+	}
+	lease->dlm_server_sock = dlm_server_sock;
+	return true;
+}
+
+static bool lease_recv_fd(struct dlm_lease *lease)
+{
+	char ctrl_buf[CMSG_SPACE(sizeof(int))] = {0};
+	char data[1] = {0};
+
+	struct iovec iov[1];
+	iov[0].iov_base = data;
+	iov[0].iov_len = sizeof(data);
+
+	struct msghdr msg = {
+	    .msg_control = ctrl_buf,
+	    .msg_controllen = CMSG_SPACE(sizeof(int)),
+	    .msg_iov = iov,
+	    .msg_iovlen = 1,
+	};
+
+	int ret;
+	while ((ret = recvmsg(lease->dlm_server_sock, &msg, 0)) <= 0) {
+		if (ret == 0) {
+			errno = EACCES;
+			DEBUG_LOG("Request rejected by DRM lease manager\n");
+			// TODO: Report why the request was rejected.
+			return false;
+		}
+		if (errno != EINTR) {
+			DEBUG_LOG("Socket data receive error: %s\n",
+				  strerror(errno));
+			return false;
+		}
+	}
+
+	lease->lease_fd = -1;
+	struct cmsghdr *cmsg;
+	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
+	     cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+		if (cmsg->cmsg_level == SOL_SOCKET &&
+		    cmsg->cmsg_type == SCM_RIGHTS) {
+			int nfds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+			int *fds = (int *)CMSG_DATA(cmsg);
+
+			if (nfds == 1) {
+				lease->lease_fd = fds[0];
+				break;
+			}
+
+			DEBUG_LOG(
+			    "Expected 1 fd from lease manager. Received %d\n",
+			    nfds);
+			/* Close any unexpected fds so we don't leak them. */
+			for (int i = 0; i < nfds; i++)
+				close(fds[i]);
+			break;
+		}
+	}
+
+	if (lease->lease_fd < 0) {
+		DEBUG_LOG("Expected data not received from lease manager\n");
+		errno = EPROTO;
+		return false;
+	}
+
+	return true;
+}
+
+struct dlm_lease *dlm_get_lease(const char *name)
+{
+	struct dlm_lease *lease = calloc(1, sizeof(struct dlm_lease));
+	if (!lease) {
+		DEBUG_LOG("can't allocate memory : %s\n", strerror(errno));
+		return NULL;
+	}
+
+	if (!lease_connect(lease, name)) {
+		free(lease);
+		return NULL;
+	}
+
+	if (!lease_recv_fd(lease)) {
+		close(lease->dlm_server_sock);
+		free(lease);
+		return NULL;
+	}
+
+	return lease;
+}
+
+void dlm_release_lease(struct dlm_lease *lease)
+{
+	if (!lease)
+		return;
+
+	close(lease->lease_fd);
+	close(lease->dlm_server_sock);
+	free(lease);
+}
+
+int dlm_lease_fd(struct dlm_lease *lease)
+{
+	if (!lease)
+		return -1;
+
+	return lease->lease_fd;
+}