1 files changed, 193 insertions, 0 deletions
diff --git a/test/syscalls/linux/alarm.cc b/test/syscalls/linux/alarm.cc
new file mode 100644
index 000000000..e0ddbb415
--- /dev/null
+++ b/test/syscalls/linux/alarm.cc
@@ -0,0 +1,193 @@
+// Copyright 2018 Google LLC
+//
+// 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 <signal.h>
+#include <unistd.h>
+
+#include "gtest/gtest.h"
+#include "absl/time/clock.h"
+#include "absl/time/time.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/logging.h"
+#include "test/util/signal_util.h"
+#include "test/util/test_util.h"
+#include "test/util/thread_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+// N.B. Below, main blocks SIGALRM. Test cases must unblock it if they want
+// delivery.
+
+void do_nothing_handler(int sig, siginfo_t* siginfo, void* arg) {}
+
+// No random save as the test relies on alarm timing. Cooperative save tests
+// already cover the save between alarm and read.
+TEST(AlarmTest, Interrupt_NoRandomSave) {
+  int pipe_fds[2];
+  ASSERT_THAT(pipe(pipe_fds), SyscallSucceeds());
+
+  FileDescriptor read_fd(pipe_fds[0]);
+  FileDescriptor write_fd(pipe_fds[1]);
+
+  // Use a signal handler that interrupts but does nothing rather than using the
+  // default terminate action.
+  struct sigaction sa;
+  sa.sa_sigaction = do_nothing_handler;
+  sigfillset(&sa.sa_mask);
+  sa.sa_flags = 0;
+  auto sa_cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGALRM, sa));
+
+  // Actually allow SIGALRM delivery.
+  auto mask_cleanup =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_UNBLOCK, SIGALRM));
+
+  // Alarm in 20 second, which should be well after read blocks below.
+  ASSERT_THAT(alarm(20), SyscallSucceeds());
+
+  char buf;
+  ASSERT_THAT(read(read_fd.get(), &buf, 1), SyscallFailsWithErrno(EINTR));
+}
+
+/* Count of the number of SIGALARMS handled. */
+static volatile int alarms_received = 0;
+
+void inc_alarms_handler(int sig, siginfo_t* siginfo, void* arg) {
+  alarms_received++;
+}
+
+// No random save as the test relies on alarm timing. Cooperative save tests
+// already cover the save between alarm and read.
+TEST(AlarmTest, Restart_NoRandomSave) {
+  alarms_received = 0;
+
+  int pipe_fds[2];
+  ASSERT_THAT(pipe(pipe_fds), SyscallSucceeds());
+
+  FileDescriptor read_fd(pipe_fds[0]);
+  // Write end closed by thread below.
+
+  struct sigaction sa;
+  sa.sa_sigaction = inc_alarms_handler;
+  sigfillset(&sa.sa_mask);
+  sa.sa_flags = SA_RESTART;
+  auto sa_cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGALRM, sa));
+
+  // Spawn a thread to eventually unblock the read below.
+  ScopedThread t([pipe_fds] {
+    absl::SleepFor(absl::Seconds(30));
+    EXPECT_THAT(close(pipe_fds[1]), SyscallSucceeds());
+  });
+
+  // Actually allow SIGALRM delivery.
+  auto mask_cleanup =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_UNBLOCK, SIGALRM));
+
+  // Alarm in 20 second, which should be well after read blocks below, but
+  // before it returns.
+  ASSERT_THAT(alarm(20), SyscallSucceeds());
+
+  // Read and eventually get an EOF from the writer closing.  If SA_RESTART
+  // didn't work, then the alarm would not have fired and we wouldn't increment
+  // our alarms_received count in our signal handler, or we would have not
+  // restarted the syscall gracefully, which we expect below in order to be
+  // able to get the final EOF on the pipe.
+  char buf;
+  ASSERT_THAT(read(read_fd.get(), &buf, 1), SyscallSucceeds());
+  EXPECT_EQ(alarms_received, 1);
+
+  t.Join();
+}
+
+// No random save as the test relies on alarm timing. Cooperative save tests
+// already cover the save between alarm and pause.
+TEST(AlarmTest, SaSiginfo_NoRandomSave) {
+  // Use a signal handler that interrupts but does nothing rather than using the
+  // default terminate action.
+  struct sigaction sa;
+  sa.sa_sigaction = do_nothing_handler;
+  sigfillset(&sa.sa_mask);
+  sa.sa_flags = SA_SIGINFO;
+  auto sa_cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGALRM, sa));
+
+  // Actually allow SIGALRM delivery.
+  auto mask_cleanup =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_UNBLOCK, SIGALRM));
+
+  // Alarm in 20 second, which should be well after pause blocks below.
+  ASSERT_THAT(alarm(20), SyscallSucceeds());
+  ASSERT_THAT(pause(), SyscallFailsWithErrno(EINTR));
+}
+
+// No random save as the test relies on alarm timing. Cooperative save tests
+// already cover the save between alarm and pause.
+TEST(AlarmTest, SaInterrupt_NoRandomSave) {
+  // Use a signal handler that interrupts but does nothing rather than using the
+  // default terminate action.
+  struct sigaction sa;
+  sa.sa_sigaction = do_nothing_handler;
+  sigfillset(&sa.sa_mask);
+  sa.sa_flags = SA_INTERRUPT;
+  auto sa_cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGALRM, sa));
+
+  // Actually allow SIGALRM delivery.
+  auto mask_cleanup =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_UNBLOCK, SIGALRM));
+
+  // Alarm in 20 second, which should be well after pause blocks below.
+  ASSERT_THAT(alarm(20), SyscallSucceeds());
+  ASSERT_THAT(pause(), SyscallFailsWithErrno(EINTR));
+}
+
+TEST(AlarmTest, UserModeSpinning) {
+  alarms_received = 0;
+
+  struct sigaction sa = {};
+  sa.sa_sigaction = inc_alarms_handler;
+  sigfillset(&sa.sa_mask);
+  sa.sa_flags = SA_SIGINFO;
+  auto sa_cleanup = ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGALRM, sa));
+
+  // Actually allow SIGALRM delivery.
+  auto mask_cleanup =
+      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_UNBLOCK, SIGALRM));
+
+  // Alarm in 20 second, which should be well into the loop below.
+  ASSERT_THAT(alarm(20), SyscallSucceeds());
+  // Make sure that the signal gets delivered even if we are spinning in user
+  // mode when it arrives.
+  while (!alarms_received) {
+  }
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
+
+int main(int argc, char** argv) {
+  // These tests depend on delivering SIGALRM to the main thread. Block SIGALRM
+  // so that any other threads created by TestInit will also have SIGALRM
+  // blocked.
+  sigset_t set;
+  sigemptyset(&set);
+  sigaddset(&set, SIGALRM);
+  TEST_PCHECK(sigprocmask(SIG_BLOCK, &set, nullptr) == 0);
+
+  gvisor::testing::TestInit(&argc, &argv);
+
+  return RUN_ALL_TESTS();
+}