Add wrappers for pidfd_{open,getfd,send_signal}.
Bug: http://b/172518739
Test: `/data/nativetest64/bionic-unit-tests/bionic-unit-tests --gtest_filter="*pidfd*"` on blueline
Change-Id: Ibae32bbedbcf26535a80a5cbfb55ce180906b610
diff --git a/tests/pidfd_test.cpp b/tests/pidfd_test.cpp
new file mode 100644
index 0000000..7c691ef
--- /dev/null
+++ b/tests/pidfd_test.cpp
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2021 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 <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#if defined(__BIONIC__)
+#include <sys/pidfd.h>
+#endif
+
+#include <android-base/unique_fd.h>
+
+#include <gtest/gtest.h>
+
+#include "BionicDeathTest.h"
+
+using android::base::unique_fd;
+using namespace std::chrono_literals;
+
+using pidfd_DeathTest = BionicDeathTest;
+
+TEST(pidfd, pidfd_open) {
+#if defined(__BIONIC__)
+ pid_t child = fork();
+ ASSERT_NE(-1, child);
+ if (child == 0) {
+ _exit(42);
+ }
+
+ unique_fd pidfd(pidfd_open(child, 0));
+ if (pidfd.get() == -1) {
+ ASSERT_EQ(ENOSYS, errno);
+ GTEST_SKIP() << "pidfd_open not available";
+ }
+
+ siginfo_t siginfo;
+ int rc = waitid(P_PIDFD, pidfd.get(), &siginfo, WEXITED);
+ if (rc == -1) {
+ ASSERT_EQ(EINVAL, errno) << strerror(errno);
+ GTEST_SKIP() << "P_PIDFD not available";
+ }
+
+ ASSERT_EQ(child, siginfo.si_pid);
+#endif
+}
+
+TEST(pidfd, pidfd_getfd) {
+#if defined(__BIONIC__)
+ unique_fd r, w;
+ ASSERT_TRUE(android::base::Pipe(&r, &w));
+ unique_fd self(pidfd_open(getpid(), 0));
+ if (self.get() == -1) {
+ ASSERT_EQ(ENOSYS, errno);
+ GTEST_SKIP() << "pidfd_open not available";
+ }
+
+ unique_fd dup(pidfd_getfd(self.get(), r.get(), 0));
+ if (dup.get() == -1) {
+ ASSERT_EQ(ENOSYS, errno) << strerror(errno);
+ GTEST_SKIP() << "pidfd_getfd not available";
+ }
+
+ ASSERT_NE(r.get(), dup.get());
+ ASSERT_EQ(3, write(w.get(), "foo", 3));
+ char buf[4];
+ ASSERT_EQ(3, read(dup.get(), buf, sizeof(buf)));
+ ASSERT_EQ(0, memcmp(buf, "foo", 3));
+#endif
+}
+
+TEST_F(pidfd_DeathTest, pidfd_send_signal) {
+#if defined(__BIONIC__)
+ unique_fd self(pidfd_open(getpid(), 0));
+ if (self.get() == -1) {
+ ASSERT_EQ(ENOSYS, errno);
+ GTEST_SKIP() << "pidfd_open not available";
+ }
+
+ if (pidfd_send_signal(self.get(), 0, nullptr, 0) == -1) {
+ ASSERT_EQ(ENOSYS, errno);
+ GTEST_SKIP() << "pidfd_send_signal not available";
+ }
+
+ ASSERT_EXIT(({
+ // gtest will fork a child off for ASSERT_EXIT: `self` refers to the parent.
+ unique_fd child(pidfd_open(getpid(), 0));
+ pidfd_send_signal(child.get(), SIGINT, nullptr, 0);
+ }),
+ testing::KilledBySignal(SIGINT), "");
+
+#endif
+}