gvisor/test/syscalls/linux/fifo.cc

// Copyright 2021 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 <fcntl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>

#include <vector>

#include "gtest/gtest.h"
#include "test/util/file_descriptor.h"
#include "test/util/signal_util.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
#include "test/util/thread_util.h"
#include "test/util/timer_util.h"

namespace gvisor {
namespace testing {

namespace {

PosixErrorOr<FileDescriptor> OpenRetryEINTR(std::string const& path, int flags,
                                            mode_t mode = 0) {
  while (true) {
    auto maybe_fd = Open(path, flags, mode);
    if (maybe_fd.ok() || maybe_fd.error().errno_value() != EINTR) {
      return maybe_fd;
    }
  }
}

TEST(FifoTest, MknodAtFIFO) {
  const TempPath dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
  const std::string fifo_relpath = NewTempRelPath();
  const std::string fifo = JoinPath(dir.path(), fifo_relpath);

  const FileDescriptor dirfd =
      ASSERT_NO_ERRNO_AND_VALUE(Open(dir.path().c_str(), O_RDONLY));
  ASSERT_THAT(mknodat(dirfd.get(), fifo_relpath.c_str(), S_IFIFO | S_IRUSR, 0),
              SyscallSucceeds());

  struct stat st;
  ASSERT_THAT(stat(fifo.c_str(), &st), SyscallSucceeds());
  EXPECT_TRUE(S_ISFIFO(st.st_mode));
}

TEST(FifoTest, Fifo) {
  const std::string fifo = NewTempAbsPath();
  ASSERT_THAT(mknod(fifo.c_str(), S_IFIFO | S_IRUSR | S_IWUSR, 0),
              SyscallSucceeds());

  struct stat st;
  ASSERT_THAT(stat(fifo.c_str(), &st), SyscallSucceeds());
  EXPECT_TRUE(S_ISFIFO(st.st_mode));

  std::string msg = "some std::string";
  std::vector<char> buf(512);

  // Read-end of the pipe.
  ScopedThread t([&fifo, &buf, &msg]() {
    FileDescriptor fd =
        ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_RDONLY));
    EXPECT_THAT(ReadFd(fd.get(), buf.data(), buf.size()),
                SyscallSucceedsWithValue(msg.length()));
    EXPECT_EQ(msg, std::string(buf.data()));
  });

  // Write-end of the pipe.
  FileDescriptor wfd =
      ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_WRONLY));
  EXPECT_THAT(WriteFd(wfd.get(), msg.c_str(), msg.length()),
              SyscallSucceedsWithValue(msg.length()));
}

TEST(FifoTest, FifoOtrunc) {
  const std::string fifo = NewTempAbsPath();
  ASSERT_THAT(mknod(fifo.c_str(), S_IFIFO | S_IRUSR | S_IWUSR, 0),
              SyscallSucceeds());

  struct stat st = {};
  ASSERT_THAT(stat(fifo.c_str(), &st), SyscallSucceeds());
  EXPECT_TRUE(S_ISFIFO(st.st_mode));

  std::string msg = "some std::string";
  std::vector<char> buf(512);
  // Read-end of the pipe.
  ScopedThread t([&fifo, &buf, &msg]() {
    FileDescriptor fd =
        ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_RDONLY));
    EXPECT_THAT(ReadFd(fd.get(), buf.data(), buf.size()),
                SyscallSucceedsWithValue(msg.length()));
    EXPECT_EQ(msg, std::string(buf.data()));
  });

  // Write-end of the pipe.
  FileDescriptor wfd = ASSERT_NO_ERRNO_AND_VALUE(
      OpenRetryEINTR(fifo.c_str(), O_WRONLY | O_TRUNC));
  EXPECT_THAT(WriteFd(wfd.get(), msg.c_str(), msg.length()),
              SyscallSucceedsWithValue(msg.length()));
}

TEST(FifoTest, FifoTruncNoOp) {
  const std::string fifo = NewTempAbsPath();
  ASSERT_THAT(mknod(fifo.c_str(), S_IFIFO | S_IRUSR | S_IWUSR, 0),
              SyscallSucceeds());

  EXPECT_THAT(truncate(fifo.c_str(), 0), SyscallFailsWithErrno(EINVAL));

  struct stat st = {};
  ASSERT_THAT(stat(fifo.c_str(), &st), SyscallSucceeds());
  EXPECT_TRUE(S_ISFIFO(st.st_mode));

  std::string msg = "some std::string";
  std::vector<char> buf(512);
  // Read-end of the pipe.
  ScopedThread t([&fifo, &buf, &msg]() {
    FileDescriptor fd =
        ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_RDONLY));
    EXPECT_THAT(ReadFd(fd.get(), buf.data(), buf.size()),
                SyscallSucceedsWithValue(msg.length()));
    EXPECT_EQ(msg, std::string(buf.data()));
  });

  FileDescriptor wfd = ASSERT_NO_ERRNO_AND_VALUE(
      OpenRetryEINTR(fifo.c_str(), O_WRONLY | O_TRUNC));
  EXPECT_THAT(ftruncate(wfd.get(), 0), SyscallFailsWithErrno(EINVAL));
  EXPECT_THAT(WriteFd(wfd.get(), msg.c_str(), msg.length()),
              SyscallSucceedsWithValue(msg.length()));
  EXPECT_THAT(ftruncate(wfd.get(), 0), SyscallFailsWithErrno(EINVAL));
}

void TestSigHandler(int sig, siginfo_t* info, void* ucontext) {}

TEST(FifoTest, OpenBlockedAndInterrupted) {
  constexpr int kSigno = SIGUSR1;
  constexpr int kSigvalue = 42;

  // Install our signal handler.
  struct sigaction sa = {};
  sa.sa_sigaction = TestSigHandler;
  sigemptyset(&sa.sa_mask);
  sa.sa_flags = SA_SIGINFO;
  const auto scoped_sigaction =
      ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(kSigno, sa));

  // Ensure that kSigno is unblocked on at least one thread.
  const auto scoped_sigmask =
      ASSERT_NO_ERRNO_AND_VALUE(ScopedSignalMask(SIG_UNBLOCK, kSigno));

  struct sigevent sev = {};
  sev.sigev_notify = SIGEV_THREAD;
  sev.sigev_signo = kSigno;
  sev.sigev_value.sival_int = kSigvalue;
  auto timer = ASSERT_NO_ERRNO_AND_VALUE(TimerCreate(CLOCK_MONOTONIC, sev));

  constexpr absl::Duration kPeriod = absl::Seconds(1);
  struct itimerspec its = {};
  its.it_value = its.it_interval = absl::ToTimespec(kPeriod);
  ASSERT_NO_ERRNO(timer.Set(0, its));

  const std::string fifo = NewTempAbsPath();
  ASSERT_THAT(mknod(fifo.c_str(), S_IFIFO | S_IRUSR | S_IWUSR, 0),
              SyscallSucceeds());

  EXPECT_THAT(open(fifo.c_str(), O_WRONLY), SyscallFailsWithErrno(EINTR));
  EXPECT_THAT(open(fifo.c_str(), O_RDONLY), SyscallFailsWithErrno(EINTR));
}

TEST(FifoTest, FifoOpenRDWR) {
  const std::string fifo = NewTempAbsPath();
  ASSERT_THAT(mknod(fifo.c_str(), S_IFIFO | S_IRUSR | S_IWUSR, 0),
              SyscallSucceeds());

  struct stat st;
  ASSERT_THAT(stat(fifo.c_str(), &st), SyscallSucceeds());
  EXPECT_TRUE(S_ISFIFO(st.st_mode));

  std::string msg = "some std::string";
  std::vector<char> buf(msg.length() + 1);

  FileDescriptor fd =
      ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_RDWR));
  EXPECT_THAT(WriteFd(fd.get(), msg.c_str(), msg.length()),
              SyscallSucceedsWithValue(msg.length()));
  EXPECT_THAT(ReadFd(fd.get(), buf.data(), msg.length()),
              SyscallSucceedsWithValue(msg.length()));
  EXPECT_EQ(msg, std::string(buf.data()));
}

}  // namespace

}  // namespace testing
}  // namespace gvisor