// 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 "test/syscalls/linux/socket_unix.h"

#include <errno.h>
#include <net/if.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <vector>

#include "gtest/gtest.h"
#include "gtest/gtest.h"
#include "absl/strings/string_view.h"
#include "test/syscalls/linux/socket_test_util.h"
#include "test/syscalls/linux/unix_domain_socket_test_util.h"
#include "test/util/test_util.h"
#include "test/util/thread_util.h"

// This file is a generic socket test file. It must be built with another file
// that provides the test types.

namespace gvisor {
namespace testing {

namespace {

TEST_P(UnixSocketPairTest, BasicFDPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  char received_data[20];
  int fd = -1;
  ASSERT_NO_FATAL_FAILURE(RecvSingleFD(sockets->second_fd(), &fd, received_data,
                                       sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  ASSERT_NO_FATAL_FAILURE(TransferTest(fd, pair->first_fd()));
}

TEST_P(UnixSocketPairTest, BasicTwoFDPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair1 =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());
  auto pair2 =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());
  int sent_fds[] = {pair1->second_fd(), pair2->second_fd()};

  ASSERT_NO_FATAL_FAILURE(
      SendFDs(sockets->first_fd(), sent_fds, 2, sent_data, sizeof(sent_data)));

  char received_data[20];
  int received_fds[] = {-1, -1};

  ASSERT_NO_FATAL_FAILURE(RecvFDs(sockets->second_fd(), received_fds, 2,
                                  received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  ASSERT_NO_FATAL_FAILURE(TransferTest(received_fds[0], pair1->first_fd()));
  ASSERT_NO_FATAL_FAILURE(TransferTest(received_fds[1], pair2->first_fd()));
}

TEST_P(UnixSocketPairTest, BasicThreeFDPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair1 =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());
  auto pair2 =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());
  auto pair3 =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());
  int sent_fds[] = {pair1->second_fd(), pair2->second_fd(), pair3->second_fd()};

  ASSERT_NO_FATAL_FAILURE(
      SendFDs(sockets->first_fd(), sent_fds, 3, sent_data, sizeof(sent_data)));

  char received_data[20];
  int received_fds[] = {-1, -1, -1};

  ASSERT_NO_FATAL_FAILURE(RecvFDs(sockets->second_fd(), received_fds, 3,
                                  received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  ASSERT_NO_FATAL_FAILURE(TransferTest(received_fds[0], pair1->first_fd()));
  ASSERT_NO_FATAL_FAILURE(TransferTest(received_fds[1], pair2->first_fd()));
  ASSERT_NO_FATAL_FAILURE(TransferTest(received_fds[2], pair3->first_fd()));
}

TEST_P(UnixSocketPairTest, BadFDPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  int sent_fd = -1;

  struct msghdr msg = {};
  char control[CMSG_SPACE(sizeof(sent_fd))];
  msg.msg_control = control;
  msg.msg_controllen = sizeof(control);

  struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
  cmsg->cmsg_len = CMSG_LEN(sizeof(sent_fd));
  cmsg->cmsg_level = SOL_SOCKET;
  cmsg->cmsg_type = SCM_RIGHTS;
  memcpy(CMSG_DATA(cmsg), &sent_fd, sizeof(sent_fd));

  struct iovec iov;
  iov.iov_base = sent_data;
  iov.iov_len = sizeof(sent_data);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;

  ASSERT_THAT(RetryEINTR(sendmsg)(sockets->first_fd(), &msg, 0),
              SyscallFailsWithErrno(EBADF));
}

// BasicFDPassNoSpace starts off by sending a single FD just like BasicFDPass.
// The difference is that when calling recvmsg, no space for FDs is provided,
// only space for the cmsg header.
TEST_P(UnixSocketPairTest, BasicFDPassNoSpace) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  char received_data[20];

  struct msghdr msg = {};
  std::vector<char> control(CMSG_SPACE(0));
  msg.msg_control = &control[0];
  msg.msg_controllen = control.size();

  struct iovec iov;
  iov.iov_base = received_data;
  iov.iov_len = sizeof(received_data);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;

  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, 0),
              SyscallSucceedsWithValue(sizeof(received_data)));

  EXPECT_EQ(msg.msg_controllen, 0);
  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}

// BasicFDPassUnalignedRecv starts off by sending a single FD just like
// BasicFDPass. The difference is that when calling recvmsg, the length of the
// receive data is only aligned on a 4 byte boundry instead of the normal 8.
TEST_P(UnixSocketPairTest, BasicFDPassUnalignedRecv) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  char received_data[20];
  int fd = -1;
  ASSERT_NO_FATAL_FAILURE(RecvSingleFDUnaligned(
      sockets->second_fd(), &fd, received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  ASSERT_NO_FATAL_FAILURE(TransferTest(fd, pair->first_fd()));
}

TEST_P(UnixSocketPairTest, ConcurrentBasicFDPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  int sockfd1 = sockets->first_fd();
  auto recv_func = [sockfd1, sent_data]() {
    char received_data[20];
    int fd = -1;
    RecvSingleFD(sockfd1, &fd, received_data, sizeof(received_data));
    ASSERT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
    char buf[20];
    ASSERT_THAT(ReadFd(fd, buf, sizeof(buf)),
                SyscallSucceedsWithValue(sizeof(buf)));
    ASSERT_THAT(WriteFd(fd, buf, sizeof(buf)),
                SyscallSucceedsWithValue(sizeof(buf)));
  };

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->second_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  ScopedThread t(recv_func);

  RandomizeBuffer(sent_data, sizeof(sent_data));
  ASSERT_THAT(WriteFd(pair->first_fd(), sent_data, sizeof(sent_data)),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  char received_data[20];
  ASSERT_THAT(ReadFd(pair->first_fd(), received_data, sizeof(received_data)),
              SyscallSucceedsWithValue(sizeof(received_data)));

  t.Join();

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}

// FDPassNoRecv checks that the control message can be safely ignored by using
// read(2) instead of recvmsg(2).
TEST_P(UnixSocketPairTest, FDPassNoRecv) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  // Read while ignoring the passed FD.
  char received_data[20];
  ASSERT_THAT(
      ReadFd(sockets->second_fd(), received_data, sizeof(received_data)),
      SyscallSucceedsWithValue(sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  // Check that the socket still works for reads and writes.
  ASSERT_NO_FATAL_FAILURE(
      TransferTest(sockets->first_fd(), sockets->second_fd()));
}

// FDPassInterspersed1 checks that sent control messages cannot be read before
// their associated data has been read.
TEST_P(UnixSocketPairTest, FDPassInterspersed1) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char written_data[20];
  RandomizeBuffer(written_data, sizeof(written_data));

  ASSERT_THAT(WriteFd(sockets->first_fd(), written_data, sizeof(written_data)),
              SyscallSucceedsWithValue(sizeof(written_data)));

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());
  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  // Check that we don't get a control message, but do get the data.
  char received_data[20];
  RecvNoCmsg(sockets->second_fd(), received_data, sizeof(received_data));
  EXPECT_EQ(0, memcmp(written_data, received_data, sizeof(written_data)));
}

// FDPassInterspersed2 checks that sent control messages cannot be read after
// their assocated data has been read while ignoring the control message by
// using read(2) instead of recvmsg(2).
TEST_P(UnixSocketPairTest, FDPassInterspersed2) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  char written_data[20];
  RandomizeBuffer(written_data, sizeof(written_data));
  ASSERT_THAT(WriteFd(sockets->first_fd(), written_data, sizeof(written_data)),
              SyscallSucceedsWithValue(sizeof(written_data)));

  char received_data[20];
  ASSERT_THAT(
      ReadFd(sockets->second_fd(), received_data, sizeof(received_data)),
      SyscallSucceedsWithValue(sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  ASSERT_NO_FATAL_FAILURE(
      RecvNoCmsg(sockets->second_fd(), received_data, sizeof(received_data)));
  EXPECT_EQ(0, memcmp(written_data, received_data, sizeof(written_data)));
}

TEST_P(UnixSocketPairTest, FDPassNotCoalesced) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data1[20];
  RandomizeBuffer(sent_data1, sizeof(sent_data1));

  auto pair1 =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair1->second_fd(),
                                       sent_data1, sizeof(sent_data1)));

  char sent_data2[20];
  RandomizeBuffer(sent_data2, sizeof(sent_data2));

  auto pair2 =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair2->second_fd(),
                                       sent_data2, sizeof(sent_data2)));

  char received_data1[sizeof(sent_data1) + sizeof(sent_data2)];
  int received_fd1 = -1;

  RecvSingleFD(sockets->second_fd(), &received_fd1, received_data1,
               sizeof(received_data1), sizeof(sent_data1));

  EXPECT_EQ(0, memcmp(sent_data1, received_data1, sizeof(sent_data1)));
  TransferTest(pair1->first_fd(), pair1->second_fd());

  char received_data2[sizeof(sent_data1) + sizeof(sent_data2)];
  int received_fd2 = -1;

  RecvSingleFD(sockets->second_fd(), &received_fd2, received_data2,
               sizeof(received_data2), sizeof(sent_data2));

  EXPECT_EQ(0, memcmp(sent_data2, received_data2, sizeof(sent_data2)));
  TransferTest(pair2->first_fd(), pair2->second_fd());
}

TEST_P(UnixSocketPairTest, FDPassPeek) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  char peek_data[20];
  int peek_fd = -1;
  PeekSingleFD(sockets->second_fd(), &peek_fd, peek_data, sizeof(peek_data));
  EXPECT_EQ(0, memcmp(sent_data, peek_data, sizeof(sent_data)));
  TransferTest(peek_fd, pair->first_fd());
  EXPECT_THAT(close(peek_fd), SyscallSucceeds());

  char received_data[20];
  int received_fd = -1;
  RecvSingleFD(sockets->second_fd(), &received_fd, received_data,
               sizeof(received_data));
  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
  TransferTest(received_fd, pair->first_fd());
  EXPECT_THAT(close(received_fd), SyscallSucceeds());
}

TEST_P(UnixSocketPairTest, BasicCredPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  struct ucred sent_creds;

  ASSERT_THAT(sent_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(sent_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(sent_creds.gid = getgid(), SyscallSucceeds());

  ASSERT_NO_FATAL_FAILURE(
      SendCreds(sockets->first_fd(), sent_creds, sent_data, sizeof(sent_data)));

  SetSoPassCred(sockets->second_fd());

  char received_data[20];
  struct ucred received_creds;
  ASSERT_NO_FATAL_FAILURE(RecvCreds(sockets->second_fd(), &received_creds,
                                    received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
  EXPECT_EQ(sent_creds.pid, received_creds.pid);
  EXPECT_EQ(sent_creds.uid, received_creds.uid);
  EXPECT_EQ(sent_creds.gid, received_creds.gid);
}

TEST_P(UnixSocketPairTest, SendNullCredsBeforeSoPassCredRecvEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  ASSERT_NO_FATAL_FAILURE(
      SendNullCmsg(sockets->first_fd(), sent_data, sizeof(sent_data)));

  SetSoPassCred(sockets->second_fd());

  char received_data[20];
  struct ucred received_creds;
  ASSERT_NO_FATAL_FAILURE(RecvCreds(sockets->second_fd(), &received_creds,
                                    received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds {
    0, 65534, 65534
  };

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);
}

TEST_P(UnixSocketPairTest, SendNullCredsAfterSoPassCredRecvEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  SetSoPassCred(sockets->second_fd());

  ASSERT_NO_FATAL_FAILURE(
      SendNullCmsg(sockets->first_fd(), sent_data, sizeof(sent_data)));

  char received_data[20];
  struct ucred received_creds;
  ASSERT_NO_FATAL_FAILURE(RecvCreds(sockets->second_fd(), &received_creds,
                                    received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds;
  ASSERT_THAT(want_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.gid = getgid(), SyscallSucceeds());

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);
}

TEST_P(UnixSocketPairTest, SendNullCredsBeforeSoPassCredSendEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  ASSERT_NO_FATAL_FAILURE(
      SendNullCmsg(sockets->first_fd(), sent_data, sizeof(sent_data)));

  SetSoPassCred(sockets->first_fd());

  char received_data[20];
  ASSERT_NO_FATAL_FAILURE(
      RecvNoCmsg(sockets->second_fd(), received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}

TEST_P(UnixSocketPairTest, SendNullCredsAfterSoPassCredSendEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  SetSoPassCred(sockets->first_fd());

  ASSERT_NO_FATAL_FAILURE(
      SendNullCmsg(sockets->first_fd(), sent_data, sizeof(sent_data)));

  char received_data[20];
  ASSERT_NO_FATAL_FAILURE(
      RecvNoCmsg(sockets->second_fd(), received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}

TEST_P(UnixSocketPairTest, SendNullCredsBeforeSoPassCredRecvEndAfterSendEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  SetSoPassCred(sockets->first_fd());

  ASSERT_NO_FATAL_FAILURE(
      SendNullCmsg(sockets->first_fd(), sent_data, sizeof(sent_data)));

  SetSoPassCred(sockets->second_fd());

  char received_data[20];
  struct ucred received_creds;
  ASSERT_NO_FATAL_FAILURE(RecvCreds(sockets->second_fd(), &received_creds,
                                    received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds;
  ASSERT_THAT(want_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.gid = getgid(), SyscallSucceeds());

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);
}

TEST_P(UnixSocketPairTest, WriteBeforeSoPassCredRecvEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  ASSERT_THAT(WriteFd(sockets->first_fd(), sent_data, sizeof(sent_data)),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  SetSoPassCred(sockets->second_fd());

  char received_data[20];

  struct ucred received_creds;
  ASSERT_NO_FATAL_FAILURE(RecvCreds(sockets->second_fd(), &received_creds,
                                    received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds {
    0, 65534, 65534
  };

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);
}

TEST_P(UnixSocketPairTest, WriteAfterSoPassCredRecvEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  SetSoPassCred(sockets->second_fd());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));
  ASSERT_THAT(WriteFd(sockets->first_fd(), sent_data, sizeof(sent_data)),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  char received_data[20];

  struct ucred received_creds;
  ASSERT_NO_FATAL_FAILURE(RecvCreds(sockets->second_fd(), &received_creds,
                                    received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds;
  ASSERT_THAT(want_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.gid = getgid(), SyscallSucceeds());

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);
}

TEST_P(UnixSocketPairTest, WriteBeforeSoPassCredSendEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  ASSERT_THAT(WriteFd(sockets->first_fd(), sent_data, sizeof(sent_data)),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  SetSoPassCred(sockets->first_fd());

  char received_data[20];
  ASSERT_NO_FATAL_FAILURE(
      RecvNoCmsg(sockets->second_fd(), received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}

TEST_P(UnixSocketPairTest, WriteAfterSoPassCredSendEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  SetSoPassCred(sockets->first_fd());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  ASSERT_THAT(WriteFd(sockets->first_fd(), sent_data, sizeof(sent_data)),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  char received_data[20];
  ASSERT_NO_FATAL_FAILURE(
      RecvNoCmsg(sockets->second_fd(), received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}

TEST_P(UnixSocketPairTest, WriteBeforeSoPassCredRecvEndAfterSendEnd) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  SetSoPassCred(sockets->first_fd());

  ASSERT_THAT(WriteFd(sockets->first_fd(), sent_data, sizeof(sent_data)),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  SetSoPassCred(sockets->second_fd());

  char received_data[20];

  struct ucred received_creds;
  ASSERT_NO_FATAL_FAILURE(RecvCreds(sockets->second_fd(), &received_creds,
                                    received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds;
  ASSERT_THAT(want_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.gid = getgid(), SyscallSucceeds());

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);
}

TEST_P(UnixSocketPairTest, SoPassCred) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int opt;
  socklen_t optLen = sizeof(opt);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_PASSCRED, &opt, &optLen),
      SyscallSucceeds());
  EXPECT_FALSE(opt);

  optLen = sizeof(opt);
  EXPECT_THAT(
      getsockopt(sockets->second_fd(), SOL_SOCKET, SO_PASSCRED, &opt, &optLen),
      SyscallSucceeds());
  EXPECT_FALSE(opt);

  SetSoPassCred(sockets->first_fd());

  optLen = sizeof(opt);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_PASSCRED, &opt, &optLen),
      SyscallSucceeds());
  EXPECT_TRUE(opt);

  optLen = sizeof(opt);
  EXPECT_THAT(
      getsockopt(sockets->second_fd(), SOL_SOCKET, SO_PASSCRED, &opt, &optLen),
      SyscallSucceeds());
  EXPECT_FALSE(opt);

  int zero = 0;
  EXPECT_THAT(setsockopt(sockets->first_fd(), SOL_SOCKET, SO_PASSCRED, &zero,
                         sizeof(zero)),
              SyscallSucceeds());

  optLen = sizeof(opt);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_PASSCRED, &opt, &optLen),
      SyscallSucceeds());
  EXPECT_FALSE(opt);

  optLen = sizeof(opt);
  EXPECT_THAT(
      getsockopt(sockets->second_fd(), SOL_SOCKET, SO_PASSCRED, &opt, &optLen),
      SyscallSucceeds());
  EXPECT_FALSE(opt);
}

TEST_P(UnixSocketPairTest, NoDataCredPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  struct msghdr msg = {};

  struct iovec iov;
  iov.iov_base = sent_data;
  iov.iov_len = sizeof(sent_data);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;

  char control[CMSG_SPACE(0)];
  msg.msg_control = control;
  msg.msg_controllen = sizeof(control);

  struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
  cmsg->cmsg_level = SOL_SOCKET;
  cmsg->cmsg_type = SCM_CREDENTIALS;
  cmsg->cmsg_len = CMSG_LEN(0);

  ASSERT_THAT(RetryEINTR(sendmsg)(sockets->first_fd(), &msg, 0),
              SyscallFailsWithErrno(EINVAL));
}

TEST_P(UnixSocketPairTest, NoPassCred) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  struct ucred sent_creds;

  ASSERT_THAT(sent_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(sent_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(sent_creds.gid = getgid(), SyscallSucceeds());

  ASSERT_NO_FATAL_FAILURE(
      SendCreds(sockets->first_fd(), sent_creds, sent_data, sizeof(sent_data)));

  char received_data[20];

  ASSERT_NO_FATAL_FAILURE(
      RecvNoCmsg(sockets->second_fd(), received_data, sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}

TEST_P(UnixSocketPairTest, CredAndFDPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  struct ucred sent_creds;

  ASSERT_THAT(sent_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(sent_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(sent_creds.gid = getgid(), SyscallSucceeds());

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendCredsAndFD(sockets->first_fd(), sent_creds,
                                         pair->second_fd(), sent_data,
                                         sizeof(sent_data)));

  SetSoPassCred(sockets->second_fd());

  char received_data[20];
  struct ucred received_creds;
  int fd = -1;
  ASSERT_NO_FATAL_FAILURE(RecvCredsAndFD(sockets->second_fd(), &received_creds,
                                         &fd, received_data,
                                         sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  EXPECT_EQ(sent_creds.pid, received_creds.pid);
  EXPECT_EQ(sent_creds.uid, received_creds.uid);
  EXPECT_EQ(sent_creds.gid, received_creds.gid);

  ASSERT_NO_FATAL_FAILURE(TransferTest(fd, pair->first_fd()));
}

TEST_P(UnixSocketPairTest, FDPassBeforeSoPassCred) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  SetSoPassCred(sockets->second_fd());

  char received_data[20];
  struct ucred received_creds;
  int fd = -1;
  ASSERT_NO_FATAL_FAILURE(RecvCredsAndFD(sockets->second_fd(), &received_creds,
                                         &fd, received_data,
                                         sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds {
    0, 65534, 65534
  };

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);

  ASSERT_NO_FATAL_FAILURE(TransferTest(fd, pair->first_fd()));
}

TEST_P(UnixSocketPairTest, FDPassAfterSoPassCred) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  SetSoPassCred(sockets->second_fd());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  char received_data[20];
  struct ucred received_creds;
  int fd = -1;
  ASSERT_NO_FATAL_FAILURE(RecvCredsAndFD(sockets->second_fd(), &received_creds,
                                         &fd, received_data,
                                         sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  struct ucred want_creds;
  ASSERT_THAT(want_creds.pid = getpid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.uid = getuid(), SyscallSucceeds());
  ASSERT_THAT(want_creds.gid = getgid(), SyscallSucceeds());

  EXPECT_EQ(want_creds.pid, received_creds.pid);
  EXPECT_EQ(want_creds.uid, received_creds.uid);
  EXPECT_EQ(want_creds.gid, received_creds.gid);

  ASSERT_NO_FATAL_FAILURE(TransferTest(fd, pair->first_fd()));
}

TEST_P(UnixSocketPairTest, CloexecDroppedWhenFDPassed) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair = ASSERT_NO_ERRNO_AND_VALUE(
      UnixDomainSocketPair(SOCK_SEQPACKET | SOCK_CLOEXEC).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  char received_data[20];
  int fd = -1;
  ASSERT_NO_FATAL_FAILURE(RecvSingleFD(sockets->second_fd(), &fd, received_data,
                                       sizeof(received_data)));

  EXPECT_THAT(fcntl(fd, F_GETFD), SyscallSucceedsWithValue(0));
}

TEST_P(UnixSocketPairTest, CloexecRecvFDPass) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  struct msghdr msg = {};
  char control[CMSG_SPACE(sizeof(int))];
  msg.msg_control = control;
  msg.msg_controllen = sizeof(control);

  struct iovec iov;
  char received_data[20];
  iov.iov_base = received_data;
  iov.iov_len = sizeof(received_data);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;

  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_CMSG_CLOEXEC),
              SyscallSucceedsWithValue(sizeof(received_data)));
  struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
  ASSERT_NE(cmsg, nullptr);
  ASSERT_EQ(cmsg->cmsg_len, CMSG_LEN(sizeof(int)));
  ASSERT_EQ(cmsg->cmsg_level, SOL_SOCKET);
  ASSERT_EQ(cmsg->cmsg_type, SCM_RIGHTS);

  int fd = -1;
  memcpy(&fd, CMSG_DATA(cmsg), sizeof(int));

  EXPECT_THAT(fcntl(fd, F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC));
}

TEST_P(UnixSocketPairTest, FDPassAfterSoPassCredWithoutCredSpace) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  SetSoPassCred(sockets->second_fd());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  struct msghdr msg = {};
  char control[CMSG_LEN(0)];
  msg.msg_control = control;
  msg.msg_controllen = sizeof(control);

  char received_data[20];
  struct iovec iov;
  iov.iov_base = received_data;
  iov.iov_len = sizeof(received_data);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;

  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, 0),
              SyscallSucceedsWithValue(sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  EXPECT_EQ(msg.msg_controllen, sizeof(control));

  struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
  ASSERT_NE(cmsg, nullptr);
  EXPECT_EQ(cmsg->cmsg_len, sizeof(control));
  EXPECT_EQ(cmsg->cmsg_level, SOL_SOCKET);
  EXPECT_EQ(cmsg->cmsg_type, SCM_CREDENTIALS);
}

// This test will validate that MSG_CTRUNC as an input flag to recvmsg will
// not appear as an output flag on the control message when truncation doesn't
// happen.
TEST_P(UnixSocketPairTest, MsgCtruncInputIsNoop) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  struct msghdr msg = {};
  char control[CMSG_SPACE(sizeof(int)) /* we're passing a single fd */];
  msg.msg_control = control;
  msg.msg_controllen = sizeof(control);

  struct iovec iov;
  char received_data[20];
  iov.iov_base = received_data;
  iov.iov_len = sizeof(received_data);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;

  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_CTRUNC),
              SyscallSucceedsWithValue(sizeof(received_data)));
  struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
  ASSERT_NE(cmsg, nullptr);
  ASSERT_EQ(cmsg->cmsg_len, CMSG_LEN(sizeof(int)));
  ASSERT_EQ(cmsg->cmsg_level, SOL_SOCKET);
  ASSERT_EQ(cmsg->cmsg_type, SCM_RIGHTS);

  // Now we should verify that MSG_CTRUNC wasn't set as an output flag.
  EXPECT_EQ(msg.msg_flags & MSG_CTRUNC, 0);
}

TEST_P(UnixSocketPairTest, FDPassAfterSoPassCredWithoutCredHeaderSpace) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[20];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  SetSoPassCred(sockets->second_fd());

  ASSERT_NO_FATAL_FAILURE(SendSingleFD(sockets->first_fd(), pair->second_fd(),
                                       sent_data, sizeof(sent_data)));

  struct msghdr msg = {};
  char control[CMSG_LEN(0) / 2];
  msg.msg_control = control;
  msg.msg_controllen = sizeof(control);

  char received_data[20];
  struct iovec iov;
  iov.iov_base = received_data;
  iov.iov_len = sizeof(received_data);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;

  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, 0),
              SyscallSucceedsWithValue(sizeof(received_data)));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
  EXPECT_EQ(msg.msg_controllen, 0);
}

TEST_P(UnixSocketPairTest, InvalidGetSockOpt) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  int opt;
  socklen_t optlen = sizeof(opt);
  EXPECT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, -1, &opt, &optlen),
              SyscallFailsWithErrno(ENOPROTOOPT));
}

TEST_P(UnixSocketPairTest, BindToBadName) {
  auto pair =
      ASSERT_NO_ERRNO_AND_VALUE(UnixDomainSocketPair(SOCK_SEQPACKET).Create());

  constexpr char kBadName[] = "/some/path/that/does/not/exist";
  sockaddr_un sockaddr;
  sockaddr.sun_family = AF_LOCAL;
  memcpy(sockaddr.sun_path, kBadName, sizeof(kBadName));

  EXPECT_THAT(
      bind(pair->first_fd(), reinterpret_cast<struct sockaddr*>(&sockaddr),
           sizeof(sockaddr)),
      SyscallFailsWithErrno(ENOENT));
}

TEST_P(UnixSocketPairTest, RecvmmsgTimeoutAfterRecv) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  char sent_data[10];
  RandomizeBuffer(sent_data, sizeof(sent_data));

  char received_data[sizeof(sent_data) * 2];
  std::vector<struct mmsghdr> msgs(2);
  std::vector<struct iovec> iovs(msgs.size());
  const int chunk_size = sizeof(received_data) / msgs.size();
  for (size_t i = 0; i < msgs.size(); i++) {
    iovs[i].iov_len = chunk_size;
    iovs[i].iov_base = &received_data[i * chunk_size];
    msgs[i].msg_hdr.msg_iov = &iovs[i];
    msgs[i].msg_hdr.msg_iovlen = 1;
  }

  ASSERT_THAT(WriteFd(sockets->first_fd(), sent_data, sizeof(sent_data)),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  struct timespec timeout = {0, 1};
  ASSERT_THAT(RetryEINTR(recvmmsg)(sockets->second_fd(), &msgs[0], msgs.size(),
                                   0, &timeout),
              SyscallSucceedsWithValue(1));

  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));

  EXPECT_EQ(chunk_size, msgs[0].msg_len);
}

TEST_P(UnixSocketPairTest, TIOCINQSucceeds) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int size = -1;
  EXPECT_THAT(ioctl(sockets->first_fd(), TIOCINQ, &size), SyscallSucceeds());
  EXPECT_EQ(size, 0);

  const char some_data[] = "dangerzone";
  ASSERT_THAT(
      RetryEINTR(send)(sockets->second_fd(), &some_data, sizeof(some_data), 0),
      SyscallSucceeds());
  EXPECT_THAT(ioctl(sockets->first_fd(), TIOCINQ, &size), SyscallSucceeds());
  EXPECT_EQ(size, sizeof(some_data));

  // Linux only reports the first message's size, which is wrong. We test for
  // the behavior described in the man page.
  SKIP_IF(!IsRunningOnGvisor());

  ASSERT_THAT(
      RetryEINTR(send)(sockets->second_fd(), &some_data, sizeof(some_data), 0),
      SyscallSucceeds());
  EXPECT_THAT(ioctl(sockets->first_fd(), TIOCINQ, &size), SyscallSucceeds());
  EXPECT_EQ(size, sizeof(some_data) * 2);
}

TEST_P(UnixSocketPairTest, TIOCOUTQSucceeds) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int size = -1;
  EXPECT_THAT(ioctl(sockets->second_fd(), TIOCOUTQ, &size), SyscallSucceeds());
  EXPECT_EQ(size, 0);

  // Linux reports bogus numbers which are related to its internal allocations.
  // We test for the behavior described in the man page.
  SKIP_IF(!IsRunningOnGvisor());

  const char some_data[] = "dangerzone";
  ASSERT_THAT(
      RetryEINTR(send)(sockets->second_fd(), &some_data, sizeof(some_data), 0),
      SyscallSucceeds());
  EXPECT_THAT(ioctl(sockets->second_fd(), TIOCOUTQ, &size), SyscallSucceeds());
  EXPECT_EQ(size, sizeof(some_data));

  ASSERT_THAT(
      RetryEINTR(send)(sockets->second_fd(), &some_data, sizeof(some_data), 0),
      SyscallSucceeds());
  EXPECT_THAT(ioctl(sockets->second_fd(), TIOCOUTQ, &size), SyscallSucceeds());
  EXPECT_EQ(size, sizeof(some_data) * 2);
}

TEST_P(UnixSocketPairTest, NetdeviceIoctlsSucceed) {
  FileDescriptor sock =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_UNIX, SOCK_DGRAM, 0));

  // Prepare the request.
  struct ifreq ifr;
  snprintf(ifr.ifr_name, IFNAMSIZ, "lo");

  // Check that the ioctl either succeeds or fails with ENODEV.
  int err = ioctl(sock.get(), SIOCGIFINDEX, &ifr);
  if (err < 0) {
    ASSERT_EQ(errno, ENODEV);
  }
}

TEST_P(UnixSocketPairTest, SocketShutdown) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  char buf[20];
  const std::string data = "abc";
  ASSERT_THAT(WriteFd(sockets->first_fd(), data.c_str(), 3),
              SyscallSucceedsWithValue(3));
  ASSERT_THAT(shutdown(sockets->first_fd(), SHUT_RDWR), SyscallSucceeds());
  ASSERT_THAT(shutdown(sockets->second_fd(), SHUT_RDWR), SyscallSucceeds());

  // Shutting down a socket does not clear the buffer.
  ASSERT_THAT(ReadFd(sockets->second_fd(), buf, 3),
              SyscallSucceedsWithValue(3));
  EXPECT_EQ(data, absl::string_view(buf, 3));
}

TEST_P(UnixSocketPairTest, SocketReopenFromProcfs) {
  // TODO: We should be returning ENXIO and NOT EIO.
  SKIP_IF(IsRunningOnGvisor());
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Opening a socket pair via /proc/self/fd/X is a ENXIO.
  for (const int fd : {sockets->first_fd(), sockets->second_fd()}) {
    ASSERT_THAT(Open(absl::StrCat("/proc/self/fd/", fd), O_WRONLY),
                PosixErrorIs(ENXIO, ::testing::_));
  }
}

}  // namespace

}  // namespace testing
}  // namespace gvisor