多进程实现高并发服务器

 

# server

/*
    多进程实现并发服务器
        主进程负责接收
        子进程负责处理

*/

#include <stdio.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <wait.h>
#include <signal.h>
#include <errno.h>

void callback(int num)
{
    // 防止终止了多个进程，未决信号集只保存了一个信号
    while(1)
    {
        int ret = waitpid(-1, NULL, WNOHANG);
        if(ret == 0) // 还有子进程活着，但未终止
            break;
        else if(ret == -1) // 所有的子进程都回收了
        {
            break;
        }
        else
        {
            printf("%d recovery successfully\n", ret);
        }
    }
}

int main()
{
    // 注册信号捕捉
    struct sigaction act;
    act.sa_handler = callback;
    act.sa_flags = 0;
    sigemptyset(&act.sa_mask);
    
    
    sigaction(SIGCHLD, &act, NULL);

    int lfd = socket(AF_INET, SOCK_STREAM, 0);
    if(lfd == -1)
    {
        perror("socket");
        exit(-1);
    }

    char *temp = "192.168.248.128";
    int inet_ip;
    struct sockaddr_in saddr;
    saddr.sin_family = AF_INET;
    inet_pton(AF_INET, temp, (void *) &inet_ip);
    saddr.sin_addr.s_addr = inet_ip;
    saddr.sin_port = htons(9999);
    int ret = bind(lfd, (struct sockaddr *) &saddr, sizeof(saddr));
    if(ret == -1)
    {
        perror("bind");
        exit(-1);
    }
    ret = listen(lfd, 5);
    if(ret == -1)
    {
        perror("listen");
        exit(-1);
    }
    int cfd_array[1024];
    int cfd_cnt = 0;
    pid_t fork_flag;
    while(1)
    {
        struct sockaddr_in client_addr;
        int client_addr_len = sizeof(client_addr);
        int cfd = accept(lfd, (struct sockaddr *) &client_addr, (void *) &client_addr_len);
        if(cfd == -1)
        {
            if(errno == EINTR)
                continue;
            perror("accept");
            exit(-1);
        }
        cfd_array[cfd_cnt++] = cfd;

        fork_flag = fork();
        if(fork_flag == -1)
        {
            perror("fork");
            exit(-1);
        }
        else if(fork_flag == 0)
        {
            char clientIP[16];
            inet_ntop(AF_INET, (void *)&client_addr.sin_addr.s_addr, clientIP, sizeof(clientIP));
            unsigned short clientPORT = ntohs(client_addr.sin_port);

            printf("client ip is %s, port is %d\n", clientIP, clientPORT);
            char recvBuf[1024] = {0};
            int recvlen = read(cfd, recvBuf, sizeof(recvBuf));
            if(recvlen == -1)
            {
                perror("read");
                exit(-1);
            }
            else if(recvlen == 0)
            {
                printf("客户端断开连接······\n");
                // 如果循环发送接收，这个地方要加 break
            }
            else
            {
                printf("recv client data: %s\n", recvBuf);
            }


            // 给客户端发送数据
            char *data = "hello, i am server";

            int len = write(cfd, data, strlen(data));
            if(len == -1)
            {
                perror("write");
                exit(-1);
            }
            break;
        }
        else if(fork_flag > 0)
        {
            continue;
        }
    }

    for(int i = 0; i < cfd_cnt; i++)
        close(cfd_array[i]);
    close(lfd);
    // if(fork_flag > 0)
    // {
    //     while(1)
    //     {
    //         ret = waitpid(-1, NULL, WNOHANG);
    //         if(ret == 0)
    //             break;
    //         else
    //         {
    //             printf("%d recovery successfully\n", ret);
    //         }
    //     }

    // }













    return 0;
}

 

# client

 

#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>

int main()
{
    int lfd = socket(AF_INET, SOCK_STREAM, 0);
    if(lfd == -1)
    {
        perror("socket");
        exit(-1);
    }

    char temp[] = "192.168.248.128";
    int serverIP;
    inet_pton(AF_INET, temp, (void *)&serverIP);



    struct sockaddr_in saddr;
    saddr.sin_family = AF_INET;
    saddr.sin_addr.s_addr = serverIP;
    saddr.sin_port = htons(9999);
    int ret = connect(lfd, (struct sockaddr *)&saddr, sizeof(saddr));
    if(ret == -1)
    {
        perror("connect");
        exit(-1);
    }
    char buf[] = "hi, i am client";
    write(lfd, buf, strlen(buf));

    // 读取客户端发送的数据
    char recvBuf[1024] = {0};
    int len = read(lfd, recvBuf, sizeof(recvBuf));
    if(len == -1)
    {
        perror("read");
        exit(-1);
    }
    else if(len == 0)
    {
        printf("服务端断开连接······\n");
    }
    else
    {
        printf("recv server data: %s\n", recvBuf);
    }

    close(lfd);




    return 0;
}