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// 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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