examples/PIPS/opencmessagequeuelibraryex/engine/src/msgqcreate.c

/*
Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
* 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.
* Neither the name of Nokia Corporation 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT HOLDER OR CONTRIBUTORS 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.

Description:  
*/


#include <errno.h>
#include <sys/msg.h>
#include <sys/sem.h>
#include "MsgQInternal.h"


/********************************************************************************
* MsgQCreate
* Description: Creates a message queue
* Inputs:
*  qName   : ULONG that represents the queue name
*  maxMsgs : ULONG that represents maximum size of messages 
*********************************************************************************/
EXPORT_C int MsgQCreate(ULONG qName, ULONG maxMsgs, ULONG qOptions, int* err) {
        int         qId;
        int         semId;
        int         semName ;
        struct msqid_ds  qStatus ;
        struct semid_ds  sStatus ;
        
        union semun {
                int              val;
                struct semid_ds* buf;
                ushort_t*                array;
        } arg ;


        int          hashInstErr;

        if (MsgQTableLookup(qName) != NULL) {
                *err = OK;
                return (OK);
        }
        else {
                if((qOptions == MSG_Q_FIFO) || (qOptions == MSG_Q_PRIORITY)) {
                        // Set msg queue options to  FIFO and create the message queue
                        qOptions= MSG_Q_FIFO ;
                        if((qId = msgget((key_t) qName ,IPC_CREAT | 0666 | IPC_EXCL )) >=0 ) {
                                //  set msg queue parameter max # bytes in queue
                                if(  msgctl(qId,IPC_STAT,&qStatus) == 0  )          
                                if( qStatus.msg_qbytes > (maxMsgs * MAX_MSG_LEN) ) {
                                        qStatus.msg_qbytes = maxMsgs * MAX_MSG_LEN ;              
                                        if( msgctl(qId,IPC_SET,&qStatus) < 0) {
                                                // delete message queue on error 
                                                msgctl(qId,IPC_RMID,0);
                                                *err = errno;
                                                return(ERROR);
                                        }
                                }
                                // create semaphore
                                semName= (key_t) qName;
                                if((semId = semget(semName, 1, IPC_CREAT | 0666 |IPC_EXCL )) >= 0 ) {
                                        // set the semaphore value
                                        arg.buf = &sStatus;              
                                        arg.val = 1;
                                        semctl(semId , 0, SETVAL, arg) ;
                                        
                                        //install queue data in hash table
                                        if(InstallMsqQTable(qName, qId, semId, &hashInstErr) == OK) {
                                                AddToMsgQTable(qName);
                                                *err = OK;                
                                                return (OK);
                                        }
                                        else {
                                                //delete semaphore on error
                                                semctl(semId,0,IPC_RMID,0) ;
                                                *err = hashInstErr;
                                        }
                                }
                                else {
                                        // delete message queue on error
                                        msgctl(qId,IPC_RMID,0);
                                        *err = errno;
                                }
                        }
                        else {
                                *err = errno;
                        }       
                }
                else
                        *err = KMsgQLibParamErr;

                return(ERROR);
        }
}

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