linux多进程并发服务器

痛定思痛。 2022-11-29 13:17 193阅读 0赞

# 多进程并发服务器 #

多进程并发服务器，[多线程版][Link 1]

#include <stdio.h>
    #include <unistd.h>
    #include <stdlib.h>
    #include <sys/types.h>
    #include <string.h>
    #include <sys/socket.h>
    #include <arpa/inet.h>
    #include <ctype.h>
    #include <signal.h>
    #include <sys/wait.h>
    #include <errno.h>
    
    //进程回收函数
    void recyle(int num){ 
        pid_t pid;
        while ((pid = waitpid(-1,NULL,WNOHANG))>0)
        { 
            printf("child died , pid = %d\n",pid);
        }
    }
    
    int main(int argc, char const *argv[])
    { 
        if(argc<2){ 
            printf("eg: ./a.out port\n");
            exit(1);
        }
        struct sockaddr_in serv_addr;
        socklen_t serv_len = sizeof(serv_addr);
        int port = atoi(argv[1]);
    
        //创建套接字
        int lfd = socket(AF_INET,SOCK_STREAM,0);
        //初始化服务器 sockaddr_in
        memset(&serv_addr,0,serv_len);
        serv_addr.sin_family = AF_INET;                 //地址族
        serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //监听本机所有的IP
        serv_addr.sin_port = htons(port);               //设置端口
        //绑定IP和端口
        bind(lfd,(struct sockaddr*)&serv_addr,serv_len);
    
        //设置同时监听的最大个数
        listen(lfd,36);
        printf("Start accept ......\n");
    
        //使用信号回收子进程pcb
        struct sigaction act;
        act.sa_handler = recyle;
        act.sa_flags = 0;
        sigemptyset(&act.sa_mask);
        sigaction(SIGCHLD,&act,NULL);
    
        struct sockaddr_in client_addr;
        socklen_t cli_len = sizeof(client_addr);
        while (1)
        { 
            //父进程接收连接请求
            //accept阻塞的时候被信号中断，处理信号对应的操作之后
            //回来之后不阻塞了，直接返回-1,这时候errno = EINTR 
            int cfd = accept(lfd,(struct sockadd*)&client_addr,&cli_len);
            while(cfd == -1 && errno == EINTR){ 
                cfd = accept(lfd,(struct sockadd*)&client_addr,&cli_len);
            }
            printf("connect sucessful\n");
            //创建子进程
            pid_t pid = fork();
            if(pid == 0){ 
                close(lfd);
                //child process
                //通信
                char ip[64];
                while (1)
                { 
                    //client ip port
                    printf("client IP: %s, port: %d\n",inet_ntop(AF_INET,&client_addr.sin_addr.s_addr,ip,sizeof(ip)),
                                                        ntohs(client_addr.sin_port));
                    char buf[1024];
                    int len = read(cfd,buf,sizeof(buf));
                    if(len == -1){ 
                        perror("read error");
                        exit(1);
                    }
                    else if(len ==0){ 
                        printf("客户端断开了连接\n");
                        close(cfd);
                        break;
                    }
                    else{ 
                        printf("recv buf: %s\n",buf);
                        write(cfd,buf,len);
                    }
                }
                //干掉子进程
                return 0;
            }
            else if(pid>0){ 
                // parent process
                close(cfd);
            }
        }
        
        close(lfd);
        return 0;
    }

## 终端1 ##

$ gcc process_server.c -o server
    $ ./server 9876
    Start accept ......
    connect sucessful
    client IP: 127.0.0.1, port: 33720
    recv buf: 001
    
    client IP: 127.0.0.1, port: 33720
    connect sucessful
    client IP: 127.0.0.1, port: 33726
    recv buf: 002
    
    client IP: 127.0.0.1, port: 33726
    recv buf: nihao
    
    client IP: 127.0.0.1, port: 33720
    recv buf: mmm
    
    client IP: 127.0.0.1, port: 33726
    客户端断开了连接
    child died , pid = 17949
    客户端断开了连接
    child died , pid = 17657
    ...

由于采用while循环，客户端断开后，没有报错

## 终端2 ##

$ nc 127.1 9876
    001
    001
    nihao
    nihao
    ^C
    $

## 终端3 ##

$ nc 127.1 9876
    002
    002
    mmm
    mmm
    ^C
    $

[Link 1]: https://blog.csdn.net/e891377/article/details/108160735