fdev: Introduce fdev for file event handling

This is an effort to keep cutting dependency to systemd.

Change-Id: I9a0c032a1095e297c7f3ac5b67827fda3658b8d9
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

1 files changed, 97 insertions, 0 deletions

diff --git a/src/fdev-epoll.c b/src/fdev-epoll.c
new file mode 100644
index 00000000..80c037d0
--- /dev/null
+++ b/src/fdev-epoll.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2018 "IoT.bzh"
+ * Author José Bollo <jose.bollo@iot.bzh>
+ *
+ * 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 <errno.h>
+#include <unistd.h>
+#include <sys/epoll.h>
+
+#define FDEV_PROVIDER
+#include "fdev.h"
+#include "fdev-epoll.h"
+
+#define epollfd(fdev_epoll)  ((int)(intptr_t)fdev_epoll)
+
+static void disable(void *closure, const struct fdev *fdev)
+{
+	struct fdev_epoll *fdev_epoll = closure;
+	epoll_ctl(epollfd(fdev_epoll), EPOLL_CTL_DEL, fdev_fd(fdev), 0);
+}
+
+static void enable(void *closure, const struct fdev *fdev)
+{
+	struct fdev_epoll *fdev_epoll = closure;
+	struct epoll_event event;
+	int rc, fd;
+
+	fd = fdev_fd(fdev);
+	event.events = fdev_events(fdev);
+	event.data.ptr = (void*)fdev;
+	rc = epoll_ctl(epollfd(fdev_epoll), EPOLL_CTL_MOD, fd, &event);
+	if (rc < 0 && errno == ENOENT)
+		epoll_ctl(epollfd(fdev_epoll), EPOLL_CTL_ADD, fd, &event);
+}
+
+static struct fdev_itf itf =
+{
+	.unref = 0,
+	.disable = disable,
+	.enable = enable
+};
+
+struct fdev_epoll *fdev_epoll_create()
+{
+	int fd = epoll_create1(EPOLL_CLOEXEC);
+	if (!fd) {
+		fd = dup(fd);
+		close(0);
+	}
+	return fd < 0 ? 0 : (struct fdev_epoll*)(intptr_t)fd;
+}
+
+void fdev_epoll_destroy(struct fdev_epoll *fdev_epoll)
+{
+	close(epollfd(fdev_epoll));
+}
+
+int fdev_epoll_fd(struct fdev_epoll *fdev_epoll)
+{
+	return epollfd(fdev_epoll);
+}
+
+struct fdev *fdev_epoll_add(struct fdev_epoll *fdev_epoll, int fd)
+{
+	struct fdev *fdev;
+
+	fdev = fdev_create(fd);
+	if (fdev)
+		fdev_set_itf(fdev, &itf, fdev_epoll);
+	return fdev;
+}
+
+void fdev_epoll_wait_and_dispatch(struct fdev_epoll *fdev_epoll, int timeout_ms)
+{
+	struct fdev *fdev;
+	struct epoll_event events[8];
+	int rc, i;
+
+	rc = epoll_wait(epollfd(fdev_epoll), events, sizeof events / sizeof *events, timeout_ms < 0 ? -1 : timeout_ms);
+	for (i = 0 ; i < rc ; i++) {
+		fdev = events[i].data.ptr;
+		fdev_dispatch(fdev, events[i].events);
+	}
+}
+