消息队列的使用

        现有一个需求要求ui和app之间完成一次通信，采用消息的方式，代码如下：

1. APP层

appmsg.h

#ifndef _APPMSG_H_
#define _APPMSG_H_

int Notify_UI_CloseHandle(char * devpath);

#endif

appmsg.c

#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <errPublic.h>
#include "appmsg.h"

#define MSG_ERROR           -1
#define MSG_CL_KEY          0x100
#define MSG_SV_KEY          0x200
#define BUF_SIZE_MAX       64
#define TEK_MSG_TYPE      110


typedef struct _TEK_MSG_DATA_
{
    long mtype;
    char mtext[BUF_SIZE_MAX];
}   TEK_MSG_DATA;


static int sndmsg_to_ui(char *devpath);
static int rcvmsg_from_ui();

/*********************************************************************
**Function: Notify_UI_CloseHandle
**Param: devpath: device path
**Return:: 0:success, -1:fail
**********************************************************************/
int Notify_UI_CloseHandle(char * devpath)
{
    int ret = 0;

    if (NULL == devpath)
    {
        errLogPrintf(ERR_FILE_SYSTEM, ERR_ERROR, "Notify_UI_CloseHandle=>param is invalid\n");
        return -1;
    }

    //Notify ui to close handler
    ret = sndmsg_to_ui(devpath);
    if (MSG_ERROR == ret)
    {
        return -1;
    }

    //Wait for ui completed close handler
    ret = rcvmsg_from_ui();
    if (MSG_ERROR == ret)
    {
        return -1;
    }

    return 0;
}

/*********************************************************************
**Function: sndmsg_to_app
**Param: NONE
**Return:: 0:success, -1:fail
**********************************************************************/
int sndmsg_to_ui(char *devpath)
{
    int ret = 0;
    int msgid = 0;
    long msgtype = 0;
    TEK_MSG_DATA data;

    //send message to notify app close handler completed
    msgid = msgget((key_t)MSG_SV_KEY, 0666 | IPC_CREAT);
    if (MSG_ERROR == msgid)
    {
        errLogPrintf(ERR_FILE_SYSTEM, ERR_ERROR, "sndmsg_to_ui=>Failed to create msgid\n");
        return -1;
    }

    data.mtype = TEK_MSG_TYPE;
    memset(data.mtext, 0x00, sizeof(data.mtext));
    memcpy(data.mtext, devpath, strlen(devpath));
    ret = msgsnd(msgid, (void *)&data, strlen(devpath), IPC_NOWAIT);
    if (MSG_ERROR == ret)
    {
        errLogPrintf(ERR_FILE_SYSTEM, ERR_ERROR, "sndmsg_to_ui fail\n");
        return -1;
    }

    return 0;
}

/*********************************************************************
**Function: rcvmsg_from_app
**Detail: rcv message from app, purpose to close all handler
**Param: NONE
**Return:: 0:success, -1:fail
**********************************************************************/
int rcvmsg_from_ui()
{
    int ret = 0;
    int msgid = 0;
    long msgtype = 0;
    TEK_MSG_DATA data;

    memset(&data, 0x00, sizeof(TEK_MSG_DATA));	
    msgid = msgget((key_t)MSG_CL_KEY, 0666 | IPC_CREAT);
    if (MSG_ERROR == msgid)
    {
        errLogPrintf(ERR_FILE_SYSTEM, ERR_ERROR, "rcvmsg_from_ui=>Failed to create msgid.\n");
        return -1;
    }

    msgtype = TEK_MSG_TYPE;
    ret = msgrcv(msgid, (void *)&data, BUF_SIZE_MAX, msgtype, 0/*IPC_NOWAIT*/);
    if (MSG_ERROR == ret)
    {
        errLogPrintf(ERR_FILE_SYSTEM, ERR_ERROR,"rcvmsg_from_ui fail\n");
        return -1;
    }

    //clear message
    msgctl(msgid, IPC_RMID, 0);

    debugLogPrintf(ERR_FILE_SYSTEM, ERR_ERROR, "rcvmsg_from_ui=>msgrcv: mtype=%d, mtext=%s\n", data.mtype, data.mtext);

    return 0;
}

2. ui层

umntoptPublic.cpp

#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <pthread.h>
#include <QDebug>
#include <umntoptPublic.h>


#define MSG_ERROR			-1
#define MSG_CL_KEY		0x100
#define MSG_SV_KEY		0x200
#define BUF_SIZE_MAX	64
#define TEK_MSG_TYPE	110

//#ifdef __cplusplus
//extern "C" {
//#endif

typedef struct _TEK_MSG_DATA_
{
	long mtype;
	char mtext[BUF_SIZE_MAX];
}	TEK_MSG_DATA;

static int rcvmsg_from_app(char *);
static int sndmsg_to_app();

static pthread_t tid_close_file=0;
void* thread_close_file(void * );
//static char dirBuf[50]={"\0"};

/*********************************************************************
**Function: rcvmsg_from_app
**Detail: rcv message from app, purpose to close all handler
**Param: NONE
**Return:: 0:success, -1:fail
**********************************************************************/
int rcvmsg_from_app(char * dirBuf)
{
	int ret = 0;
	int msgid = 0;
	long msgtype = 0;
	TEK_MSG_DATA data;

	memset(&data, 0x00, sizeof(TEK_MSG_DATA));	
	msgid = msgget((key_t)MSG_SV_KEY, 0666 | IPC_CREAT);
	if (MSG_ERROR == msgid)
	{
	        qDebug()<<"rcvmsg_from_app=>Failed to create msgid";
		return -1;
	}
	
	msgtype = TEK_MSG_TYPE;
	ret = msgrcv(msgid, (void *)&data, BUF_SIZE_MAX, msgtype, 0/*IPC_NOWAIT*/);
	if (MSG_ERROR == ret)
	{
	        qDebug()<<"rcvmsg_from_app=>Failed to msgrcv";
		return -1;
	}
	
	//clear message
	msgctl(msgid, IPC_RMID, 0);

	qDebug()<<"rcvmsg_from_app=>msgrcv: mtype="<<data.mtype<<" mtext="<<data.mtext;
        strncpy(dirBuf,data.mtext,BUF_SIZE_MAX);
	return 0;	
}

/*********************************************************************
**Function: sndmsg_to_app
**Param: NONE
**Return:: 0:success, -1:fail
**********************************************************************/
int sndmsg_to_app()
{
	int ret = 0;
	int msgid = 0;
	//long msgtype = 0;
	TEK_MSG_DATA data;

	//send message to notify app close handler completed
	msgid = msgget((key_t)MSG_CL_KEY, 0666 | IPC_CREAT);
	if (MSG_ERROR == msgid)
	{
	//	printf("sndmsg_to_app=>Failed to create msgid.\n");
		return -1;
	}
	
	data.mtype = TEK_MSG_TYPE;
	memcpy(data.mtext, "close handle completed", 22);
	ret = msgsnd(msgid, (void *)&data, 22, IPC_NOWAIT);
	if (MSG_ERROR == ret)
	{
	//	printf("sndmsg_to_app=>Failed to msgsnd\n");
		return -1;
	}
	
	return 0;	
}

int init_close_file()
{
    int ret;
//tid_recv
    ret =pthread_create(&tid_close_file, NULL, thread_close_file, NULL);
    if (!ret)
    {
        qDebug()<<"closeFile thread  start successfully. \n";
    }
    else
    {
	qDebug()<<"ret is "<<ret;
	qDebug()<<"can't create thread: "<<strerror(ret);
    }
    return 0;
}
void* thread_close_file(void * )
{
	int ret = 0;
	int brun = 1;
	char buffer[BUF_SIZE_MAX]={"\0"};
	while(brun)
	{
            qDebug()<<"enter thread_close_file";
            //Wait for notify from app
            ret = rcvmsg_from_app(buffer);
            if(MSG_ERROR == ret)
            {
		qDebug()<<"receive msg error";
            }	
		//Do close handler
		//T.D.B
		//load .so
            qDebug()<<"close directory file is "<<buffer;
            umntCloseFile(buffer);
		
        //Notify app to close handler completed
            ret = sndmsg_to_app();
            if (MSG_ERROR == ret)
            {
                qDebug()<<"send msg error";
            }
            qDebug()<<"has closed"<<buffer <<"and sent msg to ulpp";
	}
    return NULL;
}