/*
 * Copyright (C) 2019 Weber Yann
 * 
 * This file is part of PyFCGI.
 * 
 * PyFCGI is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 * 
 * PyFCGI 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 Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with PyFCGI.  If not, see <http://www.gnu.org/licenses/>.
 */
/**@defgroup IPC Inter process communication mechanism
 */
/**@file ipc.h
 * @ingroup IPC */
#ifndef __IPC_H___
#define __IPC_H___

#include <fcgiapp.h>
#include <fcgi_stdio.h> /* fcgi library; put it first*/

#include <fcntl.h>
#include <semaphore.h>
#include <sys/mman.h>
#include <sys/stat.h>

/**@brief Format for sem and shm */
#define PYFCGI_IPCNAME_FMT "/PyFCGI-%d_%s"
/**@brief Number of semaphores */
#define PYFCGI_NSEM 3

#define SEM_WSTATE 0
#define SEM_WREQS 1
#define SEM_STATS 2
/**@brief Semaphore uniq name */
#define PYFCGI_SEMNAMES {"WState", "WReqs", "SHMStats"}

#define PyFCGI_SEM(i) (PyFCGI_conf.sems[i])

#define PyFCGI_SEM_OPEN(i) (PyFCGI_conf.sems[i].sem != NULL)

/**@defgroup IPC_flags IPC component flags
 * @ingroup IPC
 * @brief For IPC component selection */
/**@brief Worker state semaphore
 * @ingroup IPC_flags */
#define IPC_WSTATE 2
/**@brief Request counter semaphore
 * @ingroup IPC_flags */
#define IPC_WREQS 4
/**@brief Monitor <-> pool semaphore
 * @ingroup IPC_flags */
#define IPC_SEMST 8
/**@brief Monitor <-> pool SHM flag
 * @ingroup IPC_flags */
#define IPC_SHMST 16

typedef unsigned short pyfcgi_ipc_flag_t;

#include "conf.h"
#include "stats.h" //to get SHM size

/**@brief Set semaphore names using master process PID as uniq key
 * @param pid_t master process PID
 */
void pyfcgi_name_IPC(pid_t master_pid);

/**@brief Do shm_open & sem_open given component indicated by flag
 * @param pyfcgi_ipc_flah_t flag a binary or combination of component flags
 * @return 0 if no error else -1
 * @note Stores the flag in configuration context 
 * @see IPC_flags
 */
int pyfcgi_IPC_init(pyfcgi_ipc_flag_t flag);
/**@brief Same than @ref pyfchi_IPC_init but with O_CREAT flag set */
int pyfcgi_IPC_create(pyfcgi_ipc_flag_t flag);

/**@brief Close previously opened IPC component (from conf context stored flag)
 * @return 0 if no error else -1
 */
int pyfcgi_IPC_close();
/**@brief IPC ressources cleanup */
int pyfcgi_IPC_destroy(pyfcgi_ipc_flag_t flag);

#endif