init: separate out epoll into a class
Test: init_tests
Bug: 64114943
Change-Id: I5f03314773b02b9e30e8e21895b6bdcfd4909e88
diff --git a/init/epoll.cpp b/init/epoll.cpp
new file mode 100644
index 0000000..4bca09e
--- /dev/null
+++ b/init/epoll.cpp
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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 "epoll.h"
+
+#include <sys/epoll.h>
+
+#include <chrono>
+#include <functional>
+#include <map>
+
+namespace android {
+namespace init {
+
+Epoll::Epoll() {}
+
+Result<Success> Epoll::Open() {
+ if (epoll_fd_ >= 0) return Success();
+ epoll_fd_.reset(epoll_create1(EPOLL_CLOEXEC));
+
+ if (epoll_fd_ == -1) {
+ return ErrnoError() << "epoll_create1 failed";
+ }
+ return Success();
+}
+
+Result<Success> Epoll::RegisterHandler(int fd, std::function<void()> handler) {
+ auto [it, inserted] = epoll_handlers_.emplace(fd, std::move(handler));
+ if (!inserted) {
+ return Error() << "Cannot specify two epoll handlers for a given FD";
+ }
+ epoll_event ev;
+ ev.events = EPOLLIN;
+ // std::map's iterators do not get invalidated until erased, so we use the
+ // pointer to the std::function in the map directly for epoll_ctl.
+ ev.data.ptr = reinterpret_cast<void*>(&it->second);
+ if (epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ev) == -1) {
+ Result<Success> result = ErrnoError() << "epoll_ctl failed to add fd";
+ epoll_handlers_.erase(fd);
+ return result;
+ }
+ return Success();
+}
+
+Result<Success> Epoll::UnregisterHandler(int fd) {
+ if (epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr) == -1) {
+ return ErrnoError() << "epoll_ctl failed to remove fd";
+ }
+ if (epoll_handlers_.erase(fd) != 1) {
+ return Error() << "Attempting to remove epoll handler for FD without an existing handler";
+ }
+ return Success();
+}
+
+Result<Success> Epoll::Wait(std::optional<std::chrono::milliseconds> timeout) {
+ int timeout_ms = -1;
+ if (timeout && timeout->count() < INT_MAX) {
+ timeout_ms = timeout->count();
+ }
+ epoll_event ev;
+ auto nr = TEMP_FAILURE_RETRY(epoll_wait(epoll_fd_, &ev, 1, timeout_ms));
+ if (nr == -1) {
+ return ErrnoError() << "epoll_wait failed";
+ } else if (nr == 1) {
+ std::invoke(*reinterpret_cast<std::function<void()>*>(ev.data.ptr));
+ }
+ return Success();
+}
+
+} // namespace init
+} // namespace android