1 files changed, 333 insertions, 0 deletions
diff --git a/test/syscalls/linux/signalfd.cc b/test/syscalls/linux/signalfd.cc
new file mode 100644
index 000000000..54c598627
--- /dev/null
+++ b/test/syscalls/linux/signalfd.cc
@@ -0,0 +1,333 @@
+// Copyright 2019 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 <errno.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/signalfd.h>
+#include <unistd.h>
+
+#include <functional>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "gtest/gtest.h"
+#include "absl/synchronization/mutex.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/posix_error.h"
+#include "test/util/signal_util.h"
+#include "test/util/test_util.h"
+#include "test/util/thread_util.h"
+
+using ::testing::KilledBySignal;
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+constexpr int kSigno = SIGUSR1;
+constexpr int kSignoAlt = SIGUSR2;
+
+// Returns a new signalfd.
+inline PosixErrorOr<FileDescriptor> NewSignalFD(sigset_t* mask, int flags = 0) {
+  int fd = signalfd(-1, mask, flags);
+  MaybeSave();
+  if (fd < 0) {
+    return PosixError(errno, "signalfd");
+  }
+  return FileDescriptor(fd);
+}
+
+TEST(Signalfd, Basic) {
+  // Create the signalfd.
+  sigset_t mask;
+  sigemptyset(&mask);
+  sigaddset(&mask, kSigno);
+  FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, 0));
+
+  // Deliver the blocked signal.
+  const auto scoped_sigmask =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_BLOCK, kSigno));
+  ASSERT_THAT(tgkill(getpid(), gettid(), kSigno), SyscallSucceeds());
+
+  // We should now read the signal.
+  struct signalfd_siginfo rbuf;
+  ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallSucceedsWithValue(sizeof(rbuf)));
+  EXPECT_EQ(rbuf.ssi_signo, kSigno);
+}
+
+TEST(Signalfd, MaskWorks) {
+  // Create two signalfds with different masks.
+  sigset_t mask1, mask2;
+  sigemptyset(&mask1);
+  sigemptyset(&mask2);
+  sigaddset(&mask1, kSigno);
+  sigaddset(&mask2, kSignoAlt);
+  FileDescriptor fd1 = ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask1, 0));
+  FileDescriptor fd2 = ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask2, 0));
+
+  // Deliver the two signals.
+  const auto scoped_sigmask1 =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_BLOCK, kSigno));
+  const auto scoped_sigmask2 =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_BLOCK, kSignoAlt));
+  ASSERT_THAT(tgkill(getpid(), gettid(), kSigno), SyscallSucceeds());
+  ASSERT_THAT(tgkill(getpid(), gettid(), kSignoAlt), SyscallSucceeds());
+
+  // We should see the signals on the appropriate signalfds.
+  //
+  // We read in the opposite order as the signals deliver above, to ensure that
+  // we don't happen to read the correct signal from the correct signalfd.
+  struct signalfd_siginfo rbuf1, rbuf2;
+  ASSERT_THAT(read(fd2.get(), &rbuf2, sizeof(rbuf2)),
+              SyscallSucceedsWithValue(sizeof(rbuf2)));
+  EXPECT_EQ(rbuf2.ssi_signo, kSignoAlt);
+  ASSERT_THAT(read(fd1.get(), &rbuf1, sizeof(rbuf1)),
+              SyscallSucceedsWithValue(sizeof(rbuf1)));
+  EXPECT_EQ(rbuf1.ssi_signo, kSigno);
+}
+
+TEST(Signalfd, Cloexec) {
+  // Exec tests confirm that O_CLOEXEC has the intended effect. We just create a
+  // signalfd with the appropriate flag here and assert that the FD has it set.
+  sigset_t mask;
+  sigemptyset(&mask);
+  FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, SFD_CLOEXEC));
+  EXPECT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC));
+}
+
+TEST(Signalfd, Blocking) {
+  // Create the signalfd in blocking mode.
+  sigset_t mask;
+  sigemptyset(&mask);
+  sigaddset(&mask, kSigno);
+  FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, 0));
+
+  // Shared tid variable.
+  absl::Mutex mu;
+  bool has_tid;
+  pid_t tid;
+
+  // Start a thread reading.
+  ScopedThread t([&] {
+    // Copy the tid and notify the caller.
+    {
+      absl::MutexLock ml(&mu);
+      tid = gettid();
+      has_tid = true;
+    }
+
+    // Read the signal from the signalfd.
+    struct signalfd_siginfo rbuf;
+    ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+                SyscallSucceedsWithValue(sizeof(rbuf)));
+    EXPECT_EQ(rbuf.ssi_signo, kSigno);
+  });
+
+  // Wait until blocked.
+  absl::MutexLock ml(&mu);
+  mu.Await(absl::Condition(&has_tid));
+
+  // Deliver the signal to either the waiting thread, or
+  // to this thread. N.B. this is a bug in the core gVisor
+  // behavior for signalfd, and needs to be fixed.
+  //
+  // See gvisor.dev/issue/139.
+  if (IsRunningOnGvisor()) {
+    ASSERT_THAT(tgkill(getpid(), gettid(), kSigno), SyscallSucceeds());
+  } else {
+    ASSERT_THAT(tgkill(getpid(), tid, kSigno), SyscallSucceeds());
+  }
+
+  // Ensure that it was received.
+  t.Join();
+}
+
+TEST(Signalfd, ThreadGroup) {
+  // Create the signalfd in blocking mode.
+  sigset_t mask;
+  sigemptyset(&mask);
+  sigaddset(&mask, kSigno);
+  FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, 0));
+
+  // Shared variable.
+  absl::Mutex mu;
+  bool first = false;
+  bool second = false;
+
+  // Start a thread reading.
+  ScopedThread t([&] {
+    // Read the signal from the signalfd.
+    struct signalfd_siginfo rbuf;
+    ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+                SyscallSucceedsWithValue(sizeof(rbuf)));
+    EXPECT_EQ(rbuf.ssi_signo, kSigno);
+
+    // Wait for the other thread.
+    absl::MutexLock ml(&mu);
+    first = true;
+    mu.Await(absl::Condition(&second));
+  });
+
+  // Deliver the signal to the threadgroup.
+  ASSERT_THAT(kill(getpid(), kSigno), SyscallSucceeds());
+
+  // Wait for the first thread to process.
+  {
+    absl::MutexLock ml(&mu);
+    mu.Await(absl::Condition(&first));
+  }
+
+  // Deliver to the thread group again (other thread still exists).
+  ASSERT_THAT(kill(getpid(), kSigno), SyscallSucceeds());
+
+  // Ensure that we can also receive it.
+  struct signalfd_siginfo rbuf;
+  ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallSucceedsWithValue(sizeof(rbuf)));
+  EXPECT_EQ(rbuf.ssi_signo, kSigno);
+
+  // Mark the test as done.
+  {
+    absl::MutexLock ml(&mu);
+    second = true;
+  }
+
+  // The other thread should be joinable.
+  t.Join();
+}
+
+TEST(Signalfd, Nonblock) {
+  // Create the signalfd in non-blocking mode.
+  sigset_t mask;
+  sigemptyset(&mask);
+  sigaddset(&mask, kSigno);
+  FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, SFD_NONBLOCK));
+
+  // We should return if we attempt to read.
+  struct signalfd_siginfo rbuf;
+  ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallFailsWithErrno(EWOULDBLOCK));
+
+  // Block and deliver the signal.
+  const auto scoped_sigmask =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_BLOCK, kSigno));
+  ASSERT_THAT(tgkill(getpid(), gettid(), kSigno), SyscallSucceeds());
+
+  // Ensure that a read actually works.
+  ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallSucceedsWithValue(sizeof(rbuf)));
+  EXPECT_EQ(rbuf.ssi_signo, kSigno);
+
+  // Should block again.
+  EXPECT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallFailsWithErrno(EWOULDBLOCK));
+}
+
+TEST(Signalfd, SetMask) {
+  // Create the signalfd matching nothing.
+  sigset_t mask;
+  sigemptyset(&mask);
+  FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, SFD_NONBLOCK));
+
+  // Block and deliver a signal.
+  const auto scoped_sigmask =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_BLOCK, kSigno));
+  ASSERT_THAT(tgkill(getpid(), gettid(), kSigno), SyscallSucceeds());
+
+  // We should have nothing.
+  struct signalfd_siginfo rbuf;
+  ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallFailsWithErrno(EWOULDBLOCK));
+
+  // Change the signal mask.
+  sigaddset(&mask, kSigno);
+  ASSERT_THAT(signalfd(fd.get(), &mask, 0), SyscallSucceeds());
+
+  // We should now have the signal.
+  ASSERT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallSucceedsWithValue(sizeof(rbuf)));
+  EXPECT_EQ(rbuf.ssi_signo, kSigno);
+}
+
+TEST(Signalfd, Poll) {
+  // Create the signalfd.
+  sigset_t mask;
+  sigemptyset(&mask);
+  sigaddset(&mask, kSigno);
+  FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, 0));
+
+  // Block the signal, and start a thread to deliver it.
+  const auto scoped_sigmask =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_BLOCK, kSigno));
+  pid_t orig_tid = gettid();
+  ScopedThread t([&] {
+    absl::SleepFor(absl::Seconds(5));
+    ASSERT_THAT(tgkill(getpid(), orig_tid, kSigno), SyscallSucceeds());
+  });
+
+  // Start polling for the signal. We expect that it is not available at the
+  // outset, but then becomes available when the signal is sent. We give a
+  // timeout of 10000ms (or the delay above + 5 seconds of additional grace
+  // time).
+  struct pollfd poll_fd = {fd.get(), POLLIN, 0};
+  EXPECT_THAT(RetryEINTR(poll)(&poll_fd, 1, 10000),
+              SyscallSucceedsWithValue(1));
+
+  // Actually read the signal to prevent delivery.
+  struct signalfd_siginfo rbuf;
+  EXPECT_THAT(read(fd.get(), &rbuf, sizeof(rbuf)),
+              SyscallSucceedsWithValue(sizeof(rbuf)));
+}
+
+TEST(Signalfd, KillStillKills) {
+  sigset_t mask;
+  sigemptyset(&mask);
+  sigaddset(&mask, SIGKILL);
+  FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(NewSignalFD(&mask, SFD_CLOEXEC));
+
+  // Just because there is a signalfd, we shouldn't see any change in behavior
+  // for unblockable signals. It's easier to test this with SIGKILL.
+  const auto scoped_sigmask =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_BLOCK, SIGKILL));
+  EXPECT_EXIT(tgkill(getpid(), gettid(), SIGKILL), KilledBySignal(SIGKILL), "");
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
+
+int main(int argc, char** argv) {
+  // These tests depend on delivering signals. Block them up front so that all
+  // other threads created by TestInit will also have them blocked, and they
+  // will not interface with the rest of the test.
+  sigset_t set;
+  sigemptyset(&set);
+  sigaddset(&set, gvisor::testing::kSigno);
+  sigaddset(&set, gvisor::testing::kSignoAlt);
+  TEST_PCHECK(sigprocmask(SIG_BLOCK, &set, nullptr) == 0);
+
+  gvisor::testing::TestInit(&argc, &argv);
+
+  return RUN_ALL_TESTS();
+}