static dmtcp::string _resolveSymlink(dmtcp::string path)
{
  dmtcp::string device = jalib::Filesystem::ResolveSymlink(path);
  if (dmtcp_real_to_virtual_pid && path.length() > 0 &&
      dmtcp::Util::strStartsWith(device, "/proc/")) {
    int index = 6;
    char *rest;
    char newpath[128];
    JASSERT(device.length() < sizeof newpath);
    pid_t realPid = strtol(&path[index], &rest, 0);
    if (realPid > 0 && *rest == '/') {
      pid_t virtualPid = dmtcp_real_to_virtual_pid(realPid);
      sprintf(newpath, "/proc/%d%s", virtualPid, rest);
      device = newpath;
    }
  }
  return device;
}
void dmtcp::DmtcpCoordinatorAPI::sendCoordinatorHandshake (
  const dmtcp::string& progname,
  UniquePid compGroup /*= UniquePid()*/,
  int np /*= -1*/,
  DmtcpMessageType msgType /*= DMT_HELLO_COORDINATOR*/)
{
  JTRACE("sending coordinator handshake")(UniquePid::ThisProcess());

  dmtcp::string hostname = jalib::Filesystem::GetCurrentHostname();
  const char *prefixPathEnv = getenv(ENV_VAR_PREFIX_PATH);
  dmtcp::string prefixDir;
  DmtcpMessage hello_local;
  hello_local.type = msgType;
  hello_local.params[0] = np;
  hello_local.compGroup = compGroup;
  hello_local.restorePort = theRestorePort;

  if (getenv(ENV_VAR_VIRTUAL_PID) == NULL) {
    hello_local.virtualPid = -1;
  } else {
    hello_local.virtualPid = (pid_t) atoi(getenv(ENV_VAR_VIRTUAL_PID));
  }

  const char* interval = getenv ( ENV_VAR_CKPT_INTR );
  /* DmtcpMessage constructor default:
   *   hello_local.theCheckpointInterval: DMTCPMESSAGE_SAME_CKPT_INTERVAL
   */
  if ( interval != NULL )
    hello_local.theCheckpointInterval = jalib::StringToInt ( interval );
  // Tell the coordinator the ckpt interval only once.  It can change later.
  _dmtcp_unsetenv ( ENV_VAR_CKPT_INTR );

  hello_local.extraBytes = hostname.length() + 1 + progname.length() + 1;

  if (prefixPathEnv != NULL) {
    /* If --prefix was defined then this process is either running on the local
     * node (the home of first process in the comptation) or a remote node.
     *
     * If the process is running on the local node, the prefix-path-env may be
     * different from the prefix-dir of this binary, in which case, we want to
     * send the prefix-path of this binary to the coordinator and the
     * coordinator will save it as the local-prefix.
     *
     * However, if this is running on a remote node, the prefix-path-env would
     * be the same as the prefix-path of this binary and we should send the
     * prefix-path-env to the coordinator and the coordinator will note this as
     * the remote-prefix.
     */
    dmtcp::string utilDirPrefix =
      jalib::Filesystem::DirName(getenv(ENV_VAR_UTILITY_DIR));
    if (utilDirPrefix == jalib::Filesystem::ResolveSymlink(prefixPathEnv)) {
      prefixDir = prefixPathEnv;
    } else {
      prefixDir = utilDirPrefix;
    }
    hello_local.extraBytes += prefixDir.length() + 1;
  }

  _coordinatorSocket << hello_local;
  _coordinatorSocket.writeAll( hostname.c_str(),hostname.length()+1);
  _coordinatorSocket.writeAll( progname.c_str(),progname.length()+1);
  if (!prefixDir.empty()) {
    _coordinatorSocket.writeAll(prefixDir.c_str(), prefixDir.length()+1);
  }
}