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Plugin 和 Loader 的区别

f12b11374cba 2023-08-13 阅读 48

文章目录

思路

每当一个客户端连接服务器后,创建一个子进程负责与该客户端通信,客户端断开连接之后,服务器回收子进程资源。

问题

信号的注册,以及回调函数的编写:

//子进程回收回调函数
void recvChild(int arg)
{
    while(1)
    {
        int ret = waitpid(-1, NULL, WNOHANG);
        if(ret > 0)
        {
            printf("recv child, the num is:%d\n", ret);
        }
        else if(ret == 0)
        {
            //还有子进程
        }
        else if(ret == -1)
        {
            //没有子进程了
            break;
        }
    }
}
	//注册信号,解决子进程的回收问题
    struct sigaction act;
    act.sa_flags = 0;
    sigemptyset(&act.sa_mask);
    act.sa_handler = recvChild;
    sigaction(SIGCHLD, &act, NULL);
 ********//
 //接收数据没有字符结束符,无法判断数据结束,
 //使用printf%s出现问题:可以将末尾增加字符结束符/0,也可以使用数据初始化(浪费资源)
//memset(recv, 0, 1024);
int len = read(cfd, recv, 1024);
recv[len] = 0;

多进程并发回环服务器代码

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

void recvChild(int arg)
{
    while(1)
    {
        int ret = waitpid(-1, NULL, WNOHANG);
        if(ret > 0)
        {
            printf("recv child, the num is:%d\n", ret);
        }
        else if(ret == 0)
        {
            //还有子进程
        }
        else if(ret == -1)
        {
            //没有子进程了
            break;
        }
    }
}

int main()
{
    //注册信号,解决子进程的回收问题
    struct sigaction act;
    act.sa_flags = 0;
    sigemptyset(&act.sa_mask);
    act.sa_handler = recvChild;
    sigaction(SIGCHLD, &act, NULL);
    //socket
    int lfd = socket(PF_INET, SOCK_STREAM, 0);
    if(lfd == -1)
    {
        perror("socket");
        exit(-1);
    }

    //bind
    struct sockaddr_in saddr;
    saddr.sin_family = AF_INET;
    inet_pton(AF_INET, "192.168.1.108", &saddr.sin_addr.s_addr);
    //saddr.sin_addr.s_addr = INADDR_ANY;
    saddr.sin_port = htons(9999);
    int ret = bind(lfd, (struct sockaddr *)&saddr, sizeof(saddr));
    if(ret == -1)
    {
        perror("bind");
        exit(-1);
    }

    //listen
    ret = listen(lfd, 2);
    if(ret == -1)
    {
        perror("listen");
        exit(-1);
    }

    int prosess_num = 0;
    while(1)
    {
        //accept
        struct sockaddr_in caddr;
        socklen_t len = sizeof(caddr);
        int cfd = accept(lfd, (struct sockaddr *)&caddr, &len);
        if(cfd == -1)
        {
            if(errno == EINTR) continue;
            perror("accept");
            exit(-1);
        }
        
        //child
        prosess_num++;
        pid_t fd = fork();
        if(fd == -1)
        {
            perror("fork");
            exit(-1);
        }
        
        if(fd == 0)
        {
            char cip[16];
            printf("the process %d link success!\n", prosess_num);
            inet_ntop(AF_INET, &caddr.sin_addr, cip, sizeof(cip));
            printf("client IP:%s, Port:%d\n\n", cip, ntohs(caddr.sin_port));
            
            char recv[1025];
            while(1)
            {
                ********//
//接收数据没有字符结束符,无法判断数据结束,
//使用printf%s出现问题:可以将末尾增加字符结束符/0,也可以使用数据初始化(浪费资源)
                //memset(recv, 0, 1024);
                int len = read(cfd, recv, 1024);
                recv[len] = 0;
                
                if(len == -1)
                {
                    perror("read");
                    exit(-1);
                }
                else if(len > 0)
                {
                    if(strcmp(recv, "break\r\n") == 0) break;
                    write(cfd, recv, len+1);
                    printf("IP:%s Port:%d: %s", cip, ntohs(caddr.sin_port), recv);
                }
                else
                {
                    printf("client is closed...\n");
                    break;
                }
            }
            printf("the process %d, IP:%s, port:%d, will close!\n", prosess_num, cip, ntohs(caddr.sin_port));
            close(cfd);
            exit(0);
        }
        
    }
    close(lfd); 

    return 0;
}

客户端代码

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

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

    struct sockaddr_in saddr;
    saddr.sin_family = AF_INET;
    int len = sizeof(saddr);
    inet_pton(AF_INET, "192.168.1.108", &saddr.sin_addr.s_addr);
    saddr.sin_port = htons(9999);
    int ret = connect(lfd, (struct sockaddr *)&saddr, sizeof(saddr));
    if(ret == -1)
    {
        perror("connect");
        exit(-1);
    }
    printf("client link success!\n");
    
    
    //由于读操作会阻塞,客户端需要先发送数据,若先读取数据,一个进程就会阻塞住,一个进程就要先发数据,如果一次数据没有接收到,则会阻塞住。
    //可以采用两个进程,发、收互不影响
    pid_t pid = fork();
    if(pid==0)
    {
        char rbuf[1024];
        while(1)
        {
            //memset(rbuf, 0, 1024);
            int lent = read(lfd, rbuf, 1024);
            if(lent > 0)
            {
                printf("send: %s", rbuf);
            }
            else if(lent == -1) perror("read");
            
            
        }
    }
    else if(pid > 0)
    {
        int i = 0;
        char sbuf[1024];
        while(1)
        {      
            i++;
            if(i > 255) i = 0;
            sprintf(sbuf, "the num is %d\n", i);
            write(lfd, sbuf,strlen(sbuf));

            sleep(1);
        }
    }
    
    close(lfd);
    return 0;
}
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