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shared_buffer.h
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/*
* Copyright (c) 2013, SERDAR GOKCEN <[email protected]>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by "asdr".
* 4. Neither the name of "asdr" nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY SERDAR GOKCEN ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL SERDAR GOKCEN BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __PCA_SHARED_BUFFER_H_
#define __PCA_SHARED_BUFFER_H_
#include <semaphore.h>
#include "transaction.h"
#define SHM_NAME "/pca_shm"
#define MAX_TRANSACTION_COUNT 2000
#define MAX_PROCESS_COUNT 100
typedef struct _shared_buffer SHAREDBUFFER;
struct _shared_buffer {
int smfd;
sem_t empty_sem;
sem_t full_sem;
sem_t mutex;
sem_t mutex2;
int transaction_count;
TRANSACTION transactions[ MAX_TRANSACTION_COUNT ];
int child_processes[ MAX_PROCESS_COUNT ];
int child_process_count;
};
/****
* create_shared_buffer
*
* Aloocates memory from shared memory area for processes.
* Initializes SHAREDBUFFER data structure, which contains
* semaphores for concurrency, array for transaction and
* array for child processes which is going to access
* this area.
*
* @param no parameter
*
* @return address of the starting point of created shared
* memory area.
*
*****/
SHAREDBUFFER* create_shared_buffer ( void );
/** 0 **/
SHAREDBUFFER* get_shared_buffer ( void );
/** 1 **/
void close_shared_buffer ( SHAREDBUFFER* shared_buffer );
/****
* destroy_shared_buffer
*
* Releases the given SHAREDBUFFER data structure witl all of inner
* data structures, semaphores and files.
*
* @param shared_buffer - address of SHAREDBUFFER data structure.
*
*****/
void destroy_shared_buffer ( SHAREDBUFFER* shared_buffer );
/****
* keep_track_of_child_process
*
* Records child itself with its pid into shared area for
* further use.
*
* @param shared_buffer - address of SHAREDBUFFER data structure.
*
*****/
void keep_track_of_child_process ( SHAREDBUFFER* shared_buffer );
/****
* kill_all_child_processes
*
* Sends SIGKILL signal to all known producer
* and consumer processes and force them to exit.
*
* @param shared_buffer - address of SHAREDBUFFER data structure.
*
*****/
void kill_all_child_processes( SHAREDBUFFER* shared_buffer );
#endif