Add initial version

[src/drm-lease-manager.git] / libdlmclient / dlmclient.c

diff --git a/libdlmclient/dlmclient.c b/libdlmclient/dlmclient.c
new file mode 100644 (file)
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;
+}