Move lease fd send/receive to dlm-protocol

[src/drm-lease-manager.git] / common / dlm-protocol.c

diff --git a/common/dlm-protocol.c b/common/dlm-protocol.c
index 4fc87b2..79aa86f 100644 (file)
--- a/common/dlm-protocol.c
+++ b/common/dlm-protocol.c
@@ -64,3 +64,86 @@ bool send_dlm_client_request(int socket, struct dlm_client_request *request)
        }
        return true;
 }
+
+int receive_lease_fd(int socket)
+{
+       int lease_fd = -1;
+       char ctrl_buf[CMSG_SPACE(sizeof(lease_fd))];
+
+       char data;
+       struct iovec iov = {.iov_base = &data, .iov_len = sizeof(data)};
+       struct msghdr msg = {
+           .msg_iov = &iov,
+           .msg_iovlen = 1,
+           .msg_control = ctrl_buf,
+           .msg_controllen = sizeof(ctrl_buf),
+       };
+
+       ssize_t len;
+       while ((len = recvmsg(socket, &msg, 0)) <= 0) {
+               if (len == 0) {
+                       errno = EACCES;
+                       goto err;
+               }
+
+               if (errno != EINTR)
+                       goto err;
+       }
+
+       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_fd = fds[0];
+                               break;
+                       }
+
+                       /* Close any unexpected fds so we don't leak them. */
+                       for (int i = 0; i < nfds; i++)
+                               close(fds[i]);
+                       break;
+               }
+       }
+
+       if (lease_fd < 0) {
+               errno = EPROTO;
+               goto err;
+       }
+
+err:
+       return lease_fd;
+}
+
+bool send_lease_fd(int socket, int lease)
+{
+       char data;
+       struct iovec iov = {
+           .iov_base = &data,
+           .iov_len = sizeof(data),
+       };
+
+       char ctrl_buf[CMSG_SPACE(sizeof(lease))] = {0};
+
+       struct msghdr msg = {
+           .msg_iov = &iov,
+           .msg_iovlen = 1,
+           .msg_controllen = sizeof(ctrl_buf),
+           .msg_control = ctrl_buf,
+       };
+
+       struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+       cmsg->cmsg_level = SOL_SOCKET;
+       cmsg->cmsg_type = SCM_RIGHTS;
+       cmsg->cmsg_len = CMSG_LEN(sizeof(lease));
+       *((int *)CMSG_DATA(cmsg)) = lease;
+
+       if (sendmsg(socket, &msg, 0) < 0)
+               return false;
+
+       return true;
+}