/*

   Unix SMB/CIFS implementation.

   Implementation of a reliable server_exists()

   Copyright (C) Volker Lendecke 2010

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "replace.h"

#include "lib/util/samba_util.h"

#include "lib/util/server_id.h"

#include "lib/util/debug.h"

#include "source3/lib/util_procid.h"

#include "source3/param/param_proto.h"

#include "serverid.h"

#include "ctdbd_conn.h"

#include "lib/messages_ctdb.h"

#include "lib/messaging/messages_dgm.h"

static bool serverid_exists_local(const struct server_id *id)

{

  bool exists = process_exists_by_pid(id->pid);

  uint64_t unique;

  int ret;

  if (!exists) {

    return false;

  }

  if (id->unique_id == SERVERID_UNIQUE_ID_NOT_TO_VERIFY) {

    return true;

  }

  ret = messaging_dgm_get_unique(id->pid, &unique);

  if (ret != 0) {

    if (ret == EACCES) {

      DBG_ERR("Access denied on msg.lock file for PID %jd, "

        "assuming process still exists\n",

        (intmax_t)id->pid);

      return true;

    }

    return false;

  }

  return (unique == id->unique_id);

}

bool serverid_exists(const struct server_id *id)

{

  if (procid_is_local(id)) {

    return serverid_exists_local(id);

  }

  if (lp_clustering()) {

    return ctdbd_process_exists(messaging_ctdb_connection(),

              id->vnn, id->pid, id->unique_id);

  }

  return false;

}