// Copyright 2018 The gVisor Authors. // // 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 <poll.h> #include <sys/resource.h> #include <sys/socket.h> #include <sys/types.h> #include <algorithm> #include <iostream> #include "gtest/gtest.h" #include "absl/synchronization/notification.h" #include "absl/time/clock.h" #include "absl/time/time.h" #include "test/syscalls/linux/base_poll_test.h" #include "test/util/eventfd_util.h" #include "test/util/file_descriptor.h" #include "test/util/logging.h" #include "test/util/test_util.h" #include "test/util/thread_util.h" namespace gvisor { namespace testing { namespace { class PollTest : public BasePollTest { protected: void SetUp() override { BasePollTest::SetUp(); } void TearDown() override { BasePollTest::TearDown(); } }; TEST_F(PollTest, InvalidFds) { // fds is invalid because it's null, but we tell ppoll the length is non-zero. EXPECT_THAT(poll(nullptr, 1, 1), SyscallFailsWithErrno(EFAULT)); EXPECT_THAT(poll(nullptr, -1, 1), SyscallFailsWithErrno(EINVAL)); } TEST_F(PollTest, NullFds) { EXPECT_THAT(poll(nullptr, 0, 10), SyscallSucceeds()); } TEST_F(PollTest, ZeroTimeout) { EXPECT_THAT(poll(nullptr, 0, 0), SyscallSucceeds()); } // If random S/R interrupts the poll, SIGALRM may be delivered before poll // restarts, causing the poll to hang forever. TEST_F(PollTest, NegativeTimeout_NoRandomSave) { // Negative timeout mean wait forever so set a timer. SetTimer(absl::Milliseconds(100)); EXPECT_THAT(poll(nullptr, 0, -1), SyscallFailsWithErrno(EINTR)); EXPECT_TRUE(TimerFired()); } TEST_F(PollTest, NonBlockingEventPOLLIN) { // Create a pipe. int fds[2]; ASSERT_THAT(pipe(fds), SyscallSucceeds()); FileDescriptor fd0(fds[0]); FileDescriptor fd1(fds[1]); // Write some data to the pipe. char s[] = "foo\n"; ASSERT_THAT(WriteFd(fd1.get(), s, strlen(s) + 1), SyscallSucceeds()); // Poll on the reader fd with POLLIN event. struct pollfd poll_fd = {fd0.get(), POLLIN, 0}; EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, 0), SyscallSucceedsWithValue(1)); // Should trigger POLLIN event. EXPECT_EQ(poll_fd.revents & POLLIN, POLLIN); } TEST_F(PollTest, BlockingEventPOLLIN) { // Create a pipe. int fds[2]; ASSERT_THAT(pipe(fds), SyscallSucceeds()); FileDescriptor fd0(fds[0]); FileDescriptor fd1(fds[1]); // Start a blocking poll on the read fd. absl::Notification notify; ScopedThread t([&fd0, ¬ify]() { notify.Notify(); // Poll on the reader fd with POLLIN event. struct pollfd poll_fd = {fd0.get(), POLLIN, 0}; EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, -1), SyscallSucceedsWithValue(1)); // Should trigger POLLIN event. EXPECT_EQ(poll_fd.revents & POLLIN, POLLIN); }); notify.WaitForNotification(); absl::SleepFor(absl::Seconds(1.0)); // Write some data to the pipe. char s[] = "foo\n"; ASSERT_THAT(WriteFd(fd1.get(), s, strlen(s) + 1), SyscallSucceeds()); } TEST_F(PollTest, NonBlockingEventPOLLHUP) { // Create a pipe. int fds[2]; ASSERT_THAT(pipe(fds), SyscallSucceeds()); FileDescriptor fd0(fds[0]); FileDescriptor fd1(fds[1]); // Close the writer fd. fd1.reset(); // Poll on the reader fd with POLLIN event. struct pollfd poll_fd = {fd0.get(), POLLIN, 0}; EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, 0), SyscallSucceedsWithValue(1)); // Should trigger POLLHUP event. EXPECT_EQ(poll_fd.revents & POLLHUP, POLLHUP); // Should not trigger POLLIN event. EXPECT_EQ(poll_fd.revents & POLLIN, 0); } TEST_F(PollTest, BlockingEventPOLLHUP) { // Create a pipe. int fds[2]; ASSERT_THAT(pipe(fds), SyscallSucceeds()); FileDescriptor fd0(fds[0]); FileDescriptor fd1(fds[1]); // Start a blocking poll on the read fd. absl::Notification notify; ScopedThread t([&fd0, ¬ify]() { notify.Notify(); // Poll on the reader fd with POLLIN event. struct pollfd poll_fd = {fd0.get(), POLLIN, 0}; EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, -1), SyscallSucceedsWithValue(1)); // Should trigger POLLHUP event. EXPECT_EQ(poll_fd.revents & POLLHUP, POLLHUP); // Should not trigger POLLIN event. EXPECT_EQ(poll_fd.revents & POLLIN, 0); }); notify.WaitForNotification(); absl::SleepFor(absl::Seconds(1.0)); // Write some data and close the writer fd. fd1.reset(); } TEST_F(PollTest, NonBlockingEventPOLLERR) { // Create a pipe. int fds[2]; ASSERT_THAT(pipe(fds), SyscallSucceeds()); FileDescriptor fd0(fds[0]); FileDescriptor fd1(fds[1]); // Close the reader fd. fd0.reset(); // Poll on the writer fd with POLLOUT event. struct pollfd poll_fd = {fd1.get(), POLLOUT, 0}; EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, 0), SyscallSucceedsWithValue(1)); // Should trigger POLLERR event. EXPECT_EQ(poll_fd.revents & POLLERR, POLLERR); // Should also trigger POLLOUT event. EXPECT_EQ(poll_fd.revents & POLLOUT, POLLOUT); } // This test will validate that if an FD is already ready on some event, whether // it's POLLIN or POLLOUT it will not immediately return unless that's actually // what the caller was interested in. TEST_F(PollTest, ImmediatelyReturnOnlyOnPollEvents) { // Create a pipe. int fds[2]; ASSERT_THAT(pipe(fds), SyscallSucceeds()); FileDescriptor fd0(fds[0]); FileDescriptor fd1(fds[1]); // Wait for read related event on the write side of the pipe, since a write // is possible on fds[1] it would mean that POLLOUT would return immediately. // We should make sure that we're not woken up with that state that we didn't // specificially request. constexpr int kTimeoutMs = 100; struct pollfd poll_fd = {fd1.get(), POLLIN | POLLPRI | POLLRDHUP, 0}; EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, kTimeoutMs), SyscallSucceedsWithValue(0)); // We should timeout. EXPECT_EQ(poll_fd.revents, 0); // Nothing should be in returned events. // Now let's poll on POLLOUT and we should get back 1 fd as being ready and // it should contain POLLOUT in the revents. poll_fd.events = POLLOUT; EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, kTimeoutMs), SyscallSucceedsWithValue(1)); // 1 fd should have an event. EXPECT_EQ(poll_fd.revents, POLLOUT); // POLLOUT should be in revents. } // This test validates that poll(2) while data is available immediately returns. TEST_F(PollTest, PollLevelTriggered) { int fds[2] = {}; ASSERT_THAT(socketpair(AF_UNIX, SOCK_STREAM, /*protocol=*/0, fds), SyscallSucceeds()); FileDescriptor fd0(fds[0]); FileDescriptor fd1(fds[1]); // Write two bytes to the socket. const char* kBuf = "aa"; ASSERT_THAT(RetryEINTR(send)(fd0.get(), kBuf, /*len=*/2, /*flags=*/0), SyscallSucceedsWithValue(2)); // 2 bytes should be written. // Poll(2) should immediately return as there is data available to read. constexpr int kInfiniteTimeout = -1; struct pollfd poll_fd = {fd1.get(), POLLIN, 0}; ASSERT_THAT(RetryEINTR(poll)(&poll_fd, /*nfds=*/1, kInfiniteTimeout), SyscallSucceedsWithValue(1)); // 1 fd should be ready to read. EXPECT_NE(poll_fd.revents & POLLIN, 0); // Read a single byte. char read_byte = 0; ASSERT_THAT(RetryEINTR(recv)(fd1.get(), &read_byte, /*len=*/1, /*flags=*/0), SyscallSucceedsWithValue(1)); // 1 byte should be read. ASSERT_EQ(read_byte, 'a'); // We should have read a single 'a'. // Create a separate pollfd for our second poll. struct pollfd poll_fd_after = {fd1.get(), POLLIN, 0}; // Poll(2) should again immediately return since we only read one byte. ASSERT_THAT(RetryEINTR(poll)(&poll_fd_after, /*nfds=*/1, kInfiniteTimeout), SyscallSucceedsWithValue(1)); // 1 fd should be ready to read. EXPECT_NE(poll_fd_after.revents & POLLIN, 0); } TEST_F(PollTest, Nfds) { // Stash value of RLIMIT_NOFILES. struct rlimit rlim; TEST_PCHECK(getrlimit(RLIMIT_NOFILE, &rlim) == 0); // gVisor caps the number of FDs that epoll can use beyond RLIMIT_NOFILE. constexpr rlim_t maxFD = 4096; if (rlim.rlim_cur > maxFD) { rlim.rlim_cur = maxFD; TEST_PCHECK(setrlimit(RLIMIT_NOFILE, &rlim) == 0); } rlim_t max_fds = rlim.rlim_cur; std::cout << "Using limit: " << max_fds << std::endl; // Create an eventfd. Since its value is initially zero, it is writable. FileDescriptor efd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()); // Create the biggest possible pollfd array such that each element is valid. // Each entry in the 'fds' array refers to the eventfd and polls for // "writable" events (events=POLLOUT). This essentially guarantees that the // poll() is a no-op and allows negative testing of the 'nfds' parameter. std::vector<struct pollfd> fds(max_fds + 1, {.fd = efd.get(), .events = POLLOUT}); // Verify that 'nfds' up to RLIMIT_NOFILE are allowed. EXPECT_THAT(RetryEINTR(poll)(fds.data(), 1, 1), SyscallSucceedsWithValue(1)); EXPECT_THAT(RetryEINTR(poll)(fds.data(), max_fds / 2, 1), SyscallSucceedsWithValue(max_fds / 2)); EXPECT_THAT(RetryEINTR(poll)(fds.data(), max_fds, 1), SyscallSucceedsWithValue(max_fds)); // If 'nfds' exceeds RLIMIT_NOFILE then it must fail with EINVAL. EXPECT_THAT(poll(fds.data(), max_fds + 1, 1), SyscallFailsWithErrno(EINVAL)); } } // namespace } // namespace testing } // namespace gvisor