Merge "Let system_server truncate tombstones."

    CrashArtifact result;

    std::optional<std::string> path;

    result.fd.reset(openat(dir_fd_, ".", O_WRONLY | O_APPEND | O_TMPFILE | O_CLOEXEC, 0640));

    result.fd.reset(openat(dir_fd_, ".", O_WRONLY | O_APPEND | O_TMPFILE | O_CLOEXEC, 0660));

    if (result.fd == -1) {

      // We might not have O_TMPFILE. Try creating with an arbitrary filename instead.

      static size_t counter = 0;

      std::string tmp_filename = StringPrintf(".temporary%zu", counter++);

      result.fd.reset(openat(dir_fd_, tmp_filename.c_str(),

                             O_WRONLY | O_APPEND | O_CREAT | O_TRUNC | O_CLOEXEC, 0640));

                             O_WRONLY | O_APPEND | O_CREAT | O_TRUNC | O_CLOEXEC, 0660));

      if (result.fd == -1) {

        PLOG(FATAL) << "failed to create temporary tombstone in " << dir_path_;

      }

}

int main(int, char* []) {

  umask(0137);

  umask(0117);

  // Don't try to connect to ourselves if we crash.

  struct sigaction action = {};