From d3bc79bc8438206ac6a14fde4eaa288fc07eee82 Mon Sep 17 00:00:00 2001
From: Brian Geffon <bgeffon@google.com>
Date: Mon, 10 Dec 2018 14:41:40 -0800
Subject: Open source system call tests.

PiperOrigin-RevId: 224886231
Change-Id: I0fccb4d994601739d8b16b1d4e6b31f40297fb22
---
 test/syscalls/linux/select.cc | 128 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 test/syscalls/linux/select.cc

(limited to 'test/syscalls/linux/select.cc')

diff --git a/test/syscalls/linux/select.cc b/test/syscalls/linux/select.cc
new file mode 100644
index 000000000..6b6fa9217
--- /dev/null
+++ b/test/syscalls/linux/select.cc
@@ -0,0 +1,128 @@
+// 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 <limits.h>
+#include <signal.h>
+#include <sys/select.h>
+
+#include "gtest/gtest.h"
+#include "gtest/gtest.h"
+#include "absl/time/time.h"
+#include "test/syscalls/linux/base_poll_test.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+namespace {
+
+class SelectTest : public BasePollTest {
+ protected:
+  void SetUp() override { BasePollTest::SetUp(); }
+  void TearDown() override { BasePollTest::TearDown(); }
+};
+
+// See that when there are no FD sets, select behaves like sleep.
+TEST_F(SelectTest, NullFds) {
+  struct timeval timeout = absl::ToTimeval(absl::Milliseconds(10));
+  ASSERT_THAT(select(0, nullptr, nullptr, nullptr, &timeout),
+              SyscallSucceeds());
+  EXPECT_EQ(timeout.tv_sec, 0);
+  EXPECT_EQ(timeout.tv_usec, 0);
+
+  timeout = absl::ToTimeval(absl::Milliseconds(10));
+  ASSERT_THAT(select(1, nullptr, nullptr, nullptr, &timeout),
+              SyscallSucceeds());
+  EXPECT_EQ(timeout.tv_sec, 0);
+  EXPECT_EQ(timeout.tv_usec, 0);
+}
+
+TEST_F(SelectTest, NegativeNfds) {
+  EXPECT_THAT(select(-1, nullptr, nullptr, nullptr, nullptr),
+              SyscallFailsWithErrno(EINVAL));
+  EXPECT_THAT(select(-100000, nullptr, nullptr, nullptr, nullptr),
+              SyscallFailsWithErrno(EINVAL));
+  EXPECT_THAT(select(INT_MIN, nullptr, nullptr, nullptr, nullptr),
+              SyscallFailsWithErrno(EINVAL));
+}
+
+TEST_F(SelectTest, ClosedFds) {
+  fd_set read_set;
+  FD_ZERO(&read_set);
+  int fd;
+  ASSERT_THAT(fd = dup(1), SyscallSucceeds());
+  ASSERT_THAT(close(fd), SyscallSucceeds());
+  FD_SET(fd, &read_set);
+  struct timeval timeout = absl::ToTimeval(absl::Milliseconds(10));
+  EXPECT_THAT(select(fd + 1, &read_set, nullptr, nullptr, &timeout),
+              SyscallFailsWithErrno(EBADF));
+}
+
+TEST_F(SelectTest, ZeroTimeout) {
+  struct timeval timeout = {};
+  EXPECT_THAT(select(1, nullptr, nullptr, nullptr, &timeout),
+              SyscallSucceeds());
+  // Ignore timeout as its value is now undefined.
+}
+
+// If random S/R interrupts the select, SIGALRM may be delivered before select
+// restarts, causing the select to hang forever.
+TEST_F(SelectTest, NoTimeout_NoRandomSave) {
+  // When there's no timeout, select may never return so set a timer.
+  SetTimer(absl::Milliseconds(100));
+  // See that we get interrupted by the timer.
+  ASSERT_THAT(select(1, nullptr, nullptr, nullptr, nullptr),
+              SyscallFailsWithErrno(EINTR));
+  EXPECT_TRUE(TimerFired());
+}
+
+TEST_F(SelectTest, InvalidTimeoutNegative) {
+  struct timeval timeout = absl::ToTimeval(absl::Microseconds(-1));
+  EXPECT_THAT(select(1, nullptr, nullptr, nullptr, &timeout),
+              SyscallFailsWithErrno(EINVAL));
+  // Ignore timeout as its value is now undefined.
+}
+
+// Verify that a signal interrupts select.
+//
+// If random S/R interrupts the select, SIGALRM may be delivered before select
+// restarts, causing the select to hang forever.
+TEST_F(SelectTest, InterruptedBySignal_NoRandomSave) {
+  absl::Duration duration(absl::Seconds(5));
+  struct timeval timeout = absl::ToTimeval(duration);
+  SetTimer(absl::Milliseconds(100));
+  ASSERT_FALSE(TimerFired());
+  ASSERT_THAT(select(1, nullptr, nullptr, nullptr, &timeout),
+              SyscallFailsWithErrno(EINTR));
+  EXPECT_TRUE(TimerFired());
+  // Ignore timeout as its value is now undefined.
+}
+
+TEST_F(SelectTest, IgnoreBitsAboveNfds) {
+  // fd_set is a bit array with at least FD_SETSIZE bits. Test that bits
+  // corresponding to file descriptors above nfds are ignored.
+  fd_set read_set;
+  FD_ZERO(&read_set);
+  constexpr int kNfds = 1;
+  for (int fd = kNfds; fd < FD_SETSIZE; fd++) {
+    FD_SET(fd, &read_set);
+  }
+  // Pass a zero timeout so that select returns immediately.
+  struct timeval timeout = {};
+  EXPECT_THAT(select(kNfds, &read_set, nullptr, nullptr, &timeout),
+              SyscallSucceedsWithValue(0));
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace gvisor
-- 
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