diff --git a/pkg/sentry/fs/fdpipe/pipe_test.go b/pkg/sentry/fs/fdpipe/pipe_test.go index ecda8df79..69abc1e71 100644 --- a/pkg/sentry/fs/fdpipe/pipe_test.go +++ b/pkg/sentry/fs/fdpipe/pipe_test.go @@ -358,9 +358,9 @@ func TestPipeReadAheadBuffer(t *testing.T) { } } -// This is very important for pipes in general because they can return EWOULDBLOCK and for -// those that block they must continue until they have read all of the data (and report it -// as such. +// This is very important for pipes in general because they can return +// EWOULDBLOCK and for those that block they must continue until they have read +// all of the data (and report it as such). func TestPipeReadsAccumulate(t *testing.T) { fds := make([]int, 2) if err := syscall.Pipe(fds); err != nil { @@ -393,8 +393,8 @@ func TestPipeReadsAccumulate(t *testing.T) { t.Fatalf("write to pipe got (%d, %v), want (%d, nil)", n, err, len(data)) } - // Construct a segment vec that is a bit more than we have written so we trigger - // an EWOULDBLOCK. + // Construct a segment vec that is a bit more than we have written so we + // trigger an EWOULDBLOCK. wantBytes := len(data) + 1 readBuffer := make([]byte, wantBytes) iov := usermem.BytesIOSequence(readBuffer) @@ -446,8 +446,8 @@ func TestPipeWritesAccumulate(t *testing.T) { wfile.Close() t.Fatalf("newPipeOperations got error %v, want nil", err) } - // Don't forget to remove the fd from the fd notifier. Otherwise other tests will - // likely be borked, because it's global :( + // Don't forget to remove the fd from the fd notifier. Otherwise other tests + // will likely be borked, because it's global :( defer p.Release() inode := fs.NewMockInode(ctx, fs.NewMockMountSource(nil), fs.StableAttr{ @@ -455,32 +455,48 @@ func TestPipeWritesAccumulate(t *testing.T) { }) file := fs.NewFile(ctx, fs.NewDirent(ctx, inode, "pipe"), fs.FileFlags{Read: true}, p) - // Construct a segment vec that is larger than the pipe size to trigger an EWOULDBLOCK. - wantBytes := 65536 * 2 + pipeSize, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(wfile.FD()), syscall.F_GETPIPE_SZ, 0) + if errno != 0 { + t.Fatalf("fcntl(F_GETPIPE_SZ) failed: %v", errno) + } + t.Logf("Pipe buffer size: %d", pipeSize) + + // Construct a segment vec that is larger than the pipe size to trigger an + // EWOULDBLOCK. + wantBytes := int(pipeSize) * 2 writeBuffer := make([]byte, wantBytes) for i := 0; i < wantBytes; i++ { writeBuffer[i] = 'a' } iov := usermem.BytesIOSequence(writeBuffer) n, err := p.Write(ctx, file, iov, 0) - total := n - iov = iov.DropFirst64(n) if err != syserror.ErrWouldBlock { t.Fatalf("Writev got error %v, want %v", err, syserror.ErrWouldBlock) } + if n != int64(pipeSize) { + t.Fatalf("Writev partial write, got: %v, want %v", n, pipeSize) + } + total := n + iov = iov.DropFirst64(n) // Read the entire pipe buf size to make space for the second half. - throwAway := make([]byte, 65536) - if n, err := syscall.Read(fds[0], throwAway); n != len(throwAway) || err != nil { - t.Fatalf("write to pipe got (%d, %v), want (%d, nil)", n, err, len(throwAway)) + readBuffer := make([]byte, n) + if n, err := syscall.Read(fds[0], readBuffer); n != len(readBuffer) || err != nil { + t.Fatalf("write to pipe got (%d, %v), want (%d, nil)", n, err, len(readBuffer)) + } + if !bytes.Equal(readBuffer, writeBuffer[:len(readBuffer)]) { + t.Fatalf("wrong data read from pipe, got: %v, want: %v", readBuffer, writeBuffer) } // This time we should not block. n, err = p.Write(ctx, file, iov, 0) - total += n if err != nil { t.Fatalf("Writev got error %v, want nil", err) } + if n != int64(pipeSize) { + t.Fatalf("Writev partial write, got: %v, want %v", n, pipeSize) + } + total += n // Assert that the result we got back is cumulative. if total != int64(wantBytes) {