if (ops->filesystem_ops->new_read_only_memory_region_from_file != nullptr &&
      ops->read_only_memory_region_ops == nullptr)
    return errors::FailedPrecondition(
        "Filesystem allows creation of readonly memory regions but no "
        "operations on them have been supplied.");

  return OkStatus();
}

// Copies a function table from plugin memory space to core memory space.
//
// This has three benefits:

static void NewRandomAccessFile(const TF_Filesystem* filesystem,
                                const char* path, TF_RandomAccessFile* file,
                                TF_Status* status) {
  int fd = open(path, O_RDONLY);
  if (fd < 0) {
    TF_SetStatusFromIOError(status, errno, path);
    return;
  }

  struct stat st;
  fstat(fd, &st);
  if (S_ISDIR(st.st_mode)) {

namespace tf_posix_filesystem {

int TransferFileContents(const char* src, const char* dst, mode_t mode,
                         off_t size) {
  int src_fd = open(src, O_RDONLY);
  if (src_fd < 0) return -1;

  // When creating file, use the same permissions as original
  mode_t open_mode = mode & (S_IRWXU | S_IRWXG | S_IRWXO);

  // O_WRONLY | O_CREAT | O_TRUNC: