Function GetOpenFileDescriptors

src/leveldb/util/env_posix_test.cc:88–104

Iterates through all possible FDs and returns the currently open ones. Returns void so the implementation can use ASSERT_EQ.

//
// Returns void so the implementation can use ASSERT_EQ.
void GetOpenFileDescriptors(std::unordered_set<int>* open_fds) {
  int max_fd = 0;
  GetMaxFileDescriptor(&max_fd);

  for (int fd = 0; fd < max_fd; ++fd) {
    if (::dup2(fd, fd) != fd) {
      // When given the same file descriptor twice, dup2() returns -1 if the
      // file descriptor is closed, or the given file descriptor if it is open.
      //
      // Double-check that dup2() is saying the fd is closed.
      ASSERT_EQ(EBADF, errno)
          << "dup2() should set errno to EBADF on closed file descriptors";
      continue;
    }
    open_fds->insert(fd);
  }
}

// Finds an FD open since a previous call to GetOpenFileDescriptors().
//