diff options
| -rw-r--r-- | pkg/sentry/kernel/pipe/pipe.go | 13 | ||||
| -rw-r--r-- | test/syscalls/linux/sendfile.cc | 28 |
2 files changed, 38 insertions, 3 deletions
diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go index 725e9db7d..62c8691f1 100644 --- a/pkg/sentry/kernel/pipe/pipe.go +++ b/pkg/sentry/kernel/pipe/pipe.go @@ -255,7 +255,8 @@ func (p *Pipe) write(ctx context.Context, ops writeOps) (int64, error) { // POSIX requires that a write smaller than atomicIOBytes (PIPE_BUF) be // atomic, but requires no atomicity for writes larger than this. wanted := ops.left() - if avail := p.max - p.view.Size(); wanted > avail { + avail := p.max - p.view.Size() + if wanted > avail { if wanted <= p.atomicIOBytes { return 0, syserror.ErrWouldBlock } @@ -268,8 +269,14 @@ func (p *Pipe) write(ctx context.Context, ops writeOps) (int64, error) { return done, err } - if wanted > done { - // Partial write due to full pipe. + if done < avail { + // Non-failure, but short write. + return done, nil + } + if done < wanted { + // Partial write due to full pipe. Note that this could also be + // the short write case above, we would expect a second call + // and the write to return zero bytes in this case. return done, syserror.ErrWouldBlock } diff --git a/test/syscalls/linux/sendfile.cc b/test/syscalls/linux/sendfile.cc index 580ab5193..ebaafe47e 100644 --- a/test/syscalls/linux/sendfile.cc +++ b/test/syscalls/linux/sendfile.cc @@ -530,6 +530,34 @@ TEST(SendFileTest, SendToSpecialFile) { SyscallSucceedsWithValue(kSize & (~7))); } +TEST(SendFileTest, SendFileToPipe) { + // Create temp file. + constexpr char kData[] = "<insert-quote-here>"; + constexpr int kDataSize = sizeof(kData) - 1; + const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith( + GetAbsoluteTestTmpdir(), kData, TempPath::kDefaultFileMode)); + const FileDescriptor inf = + ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_RDONLY)); + + // Create a pipe for sending to a pipe. + int fds[2]; + ASSERT_THAT(pipe(fds), SyscallSucceeds()); + const FileDescriptor rfd(fds[0]); + const FileDescriptor wfd(fds[1]); + + // Expect to read up to the given size. + std::vector<char> buf(kDataSize); + ScopedThread t([&]() { + absl::SleepFor(absl::Milliseconds(100)); + ASSERT_THAT(read(rfd.get(), buf.data(), buf.size()), + SyscallSucceedsWithValue(kDataSize)); + }); + + // Send with twice the size of the file, which should hit EOF. + EXPECT_THAT(sendfile(wfd.get(), inf.get(), nullptr, kDataSize * 2), + SyscallSucceedsWithValue(kDataSize)); +} + } // namespace } // namespace testing |