Skip to content

Latest commit

 

History

History
241 lines (200 loc) · 6.72 KB

多进程网络服务.md

File metadata and controls

241 lines (200 loc) · 6.72 KB

一、高性能网络服务程序

Linux的一个应用优势是可用于设计各种高性能网络服务程序，高性能的一个特点就是实现并发访问处理，及同时为多个在线用户提供服务；多进程网络服务、多线程网络服务、线程池网络服务；

二、多进程网络服务

利用Linux系统中的父子进程关系为多用户提供并发服务，是一种比较流行的并发服务技术，其基本理念是：来一个用户，启动一个服务进程。若有新连接到来，则启动子进程与其交互，服务结束后，其子进程自动退出。

模型如下：

三、代码实现

用一个整数的运算模拟多进程的网络服务。

3.1、utili.h

#include<unistd.h>
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<pthread.h>

#define SERVER_PORT  9090
#define SERVER_IP    "127.0.0.1"
#define LISTEN_QUEUE  5
#define BUFFER_SIZE   255


typedef enum{ADD,SUB,MUL,DIV,MOD, QUIT}OPER_TYPE;

typedef struct OperStruct{
    int op1;
    int op2;
    OPER_TYPE oper;
}OperStruct;

3.2、ser.c

#include"../utili.h"

void Process_Handler(int sockConn);

void Process_Handler(int sockConn){
    OperStruct op; 
    int result;
    while(1){
        int res = recv(sockConn, &op, sizeof(op), 0); 
        if(res == -1){
            printf("recv data fail.\n");
            continue;
        }   
        if(op.oper == ADD){
            result = op.op1 + op.op2;
        }else if(op.oper == SUB)
        {   
            result = op.op1 - op.op2;
        }else if(op.oper == MUL){
            result = op.op1 * op.op2;
        }else if(op.oper == DIV){
            result = op.op1 / op.op2;
        }else if(op.oper == QUIT){
            break;
        }   

        res = send(sockConn, &result, sizeof(result), 0); 
        if(res == -1){
            printf("send data fail.\n");
            continue;
        }
    }
    close(sockConn);
}

int main(void){
    int sockSer = socket(AF_INET, SOCK_STREAM, 0);
    if(sockSer == -1){
        perror("socket");
        return -1;
    }
    struct sockaddr_in addrSer, addrCli;
    addrSer.sin_family = AF_INET;
    addrSer.sin_port = htons(SERVER_PORT);
    addrSer.sin_addr.s_addr = inet_addr(SERVER_IP);

    socklen_t len = sizeof(struct sockaddr);
    int res = bind(sockSer, (struct sockaddr*)&addrSer, len);
    if(res == -1){
        perror("bind");
        close(sockSer);
        return -1;       
   }

    listen(sockSer, LISTEN_QUEUE);

    int sockConn;
    while(1){
        printf("Server Wait Client Connect.......\n");
        sockConn = accept(sockSer, (struct sockaddr*)&addrCli, &len);
        if(sockConn == -1){
            printf("Server Accept Client Connect Fail.\n");
            continue;
        }else{
            printf("Server Accept Client Connect Success.\n");
            printf("Client IP:>%s\n", inet_ntoa(addrCli.sin_addr));
            printf("Client Port:>%d\n",ntohs(addrCli.sin_port));
        }

        pid_t pid;
        pid = fork();
        if(pid == 0){
            close(sockSer);
            Process_Handler(sockConn);
            exit(0);
        }else if(pid > 0){
            close(sockConn);
            continue;    
        }else{
            printf("Create Process Fail.\n");
            continue;
        }
    }
    close(sockSer);
    return 0;
}

3.3、cli.c

#include"utili.h"

void InputData(OperStruct *pt);

void InputData(OperStruct *pt){
    printf("please input op1 and op2 : ");
    scanf("%d %d", &(pt->op1), &(pt->op2));
}

//Cli
int main(void){
    int sockCli = socket(AF_INET, SOCK_STREAM, 0); 
    if(sockCli == -1){
        perror("socket");
        return -1; 
    }   
    struct sockaddr_in addrSer;
    addrSer.sin_family = AF_INET;
    addrSer.sin_port = htons(SERVER_PORT);
    addrSer.sin_addr.s_addr = inet_addr(SERVER_IP);

    socklen_t len = sizeof(struct sockaddr);
    int res = connect(sockCli, (struct sockaddr*)&addrSer, len);
    if(res == -1){
        perror("connect");
        close(sockCli);
        return -1; 
    }else{
        printf("Client Connect Server Success.\n");
    }

    char cmd[2];
    OperStruct  op;
    int result;
    while(1){
        printf("Please input operator : ");
        scanf("%s",cmd);
        if(strcmp(cmd, "+") == 0){
            op.oper = ADD;
            InputData(&op);
        }else if(strcmp(cmd,"-") == 0){
            op.oper = SUB;
            InputData(&op);
        }else if(strcmp(cmd,"*") == 0){
            op.oper = MUL;
            InputData(&op);
        }else if(strcmp(cmd,"/") == 0){
            op.oper = DIV;
            InputData(&op);
        }else if(strcmp(cmd, "quit") == 0){
            op.oper = QUIT;
        }else{    
            printf("Cmd invalid.\n");
        }

        res = send(sockCli, &op, sizeof(op), 0);
        if(res == -1){
            printf("send data fail.\n");
            continue;
        }
        if(op.oper == QUIT)
            break;
        res = recv(sockCli, &result, sizeof(result), 0);
        if(res == -1){
            printf("recv data fail.\n");
            continue;
        }
        printf("result = %d\n", result);
    }
    close(sockCli);
    return 0;
}

3.4、运行结果

服务器端：

客户1

客户2

四、结果分析

  1. utili.h在ser.c的上一层目录，utili.h和cli.c是在同一层目录；
  2. 进程服务器：socker是引用计数器模型，close()是减少一个，并没有真正的关闭，每次创建一个进程都会给socker引用计数器加1；
  3. 缺点：
    • 启动和关闭子进程带来很大的开销；
    • 系统最多只能产生512个进程，也就是说最多只有512个客户，形成不了处理大型访问的情形；