+#include <errno.h>
+#include <sys/epoll.h>
+
+#include "event.h"
+#include "trace.h"
+
+static int epoll_fd = -1;
+
+static int init_event_handler(void)
+{
+ epoll_fd = epoll_create(1);
+ if (epoll_fd < 0) {
+ pr_err("Failed to create epoll socket: %m\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+int register_event_handler(struct eventhandler_entry *handler)
+{
+ struct epoll_event ev;
+ int ret = 0;
+
+ if (epoll_fd < 0)
+ ret = init_event_handler();
+
+ if (ret < 0)
+ return ret;
+
+ if (handler->fd < 0) {
+ pr_err("Invalid file descriptor of %d for handler %s\n",
+ handler->fd, handler->name);
+ return -1;
+ }
+
+ if (!handler->handle_event) {
+ pr_err("Handler %s missing callback function\n", handler->name);
+ return -1;
+ }
+
+ pr_debug("Registering handler for \"%s\", fd=%d\n",
+ handler->name, handler->fd);
+
+ ev.data.fd = handler->fd;
+ ev.data.ptr = handler;
+ ev.events = handler->events;
+ ret = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, handler->fd, &ev);
+ if (ret) {
+ pr_err("Failed to add epoll_fd: %m\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+int poll_events(int timeout_ms)
+{
+ struct epoll_event event;
+ struct eventhandler_entry *handler;
+ int ret;
+
+ ret = epoll_wait(epoll_fd, &event, 1, timeout_ms);
+
+ if (ret == -1) {
+ if (errno != EINTR) {
+ pr_err("epoll_wait: %m\n");
+ return -1;
+ }
+
+ /*
+ * If epoll_wait() was interrupted, better start
+ * everything again from the beginning
+ */
+ return 0;
+ }
+
+ if (ret == 0) {
+ pr_info("Timed out\n");
+ goto out;
+ }
+
+ handler = event.data.ptr;
+
+ if (!handler || !handler->handle_event) {
+ pr_err("Corrupted event handler for fd %d\n",
+ event.data.fd);
+ goto out;
+ }
+
+ pr_debug("Running handler %s to handle events from fd %d\n",
+ handler->name, handler->fd);
+ handler->handle_event(handler);
+
+out:
+ return ret;
+}
+