TCP并发服务器

//-----------------------------------------------
//TCP并发服务器
//
//-----------------------------------------------

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <strings.h>
#include <signal.h>

#define N 64


//---------------- 信号处理 -----------------

void handler(int signo)
{

    // ------------- wait --------------
    //可能由于段时间大量的子进程结束而一起发送信号可能会被内核合并成一个信号
    //而导致生产僵死状态的子进程

    //--------------- 用waitpid解决 ---------------
#if 0
    int status;
    pid_t ret;

    ret = wait(&status);
    printf("child %d terminate; exit code=%#x\n", ret, status);
#endif

    pid_t ret;

    while ((ret = waitpid(-1, NULL, WNOHANG)) > 0)
    {
        //perror("waitpid");
        printf("child %d terminate\n", ret);
    }
}

int main(int argc, char *argv[] ) //./server 192.168.1.30 9000
{
    int listenfd, connfd;
    struct sockaddr_in myaddr, peeraddr;
    socklen_t len;
    char buf[N] = {0};
    ssize_t n;
    pid_t pid;

    if (argc != 3)
    {
        printf("usage:%s serverip serverport\n", argv[0]);
        return 0;
    }

    signal(SIGCHLD, handler); // 注册信号

    //------------------创建套接字--------------------
    if ((listenfd = socket(PF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("socket");
        exit(-1);
    }

    bzero(&myaddr, sizeof(myaddr));
    bzero(&peeraddr, sizeof(peeraddr));

    myaddr.sin_family = PF_INET;
    myaddr.sin_port = htons(atoi(argv[2]));//htons(6000);
    myaddr.sin_addr.s_addr = inet_addr(argv[1]);


    //------------------ 绑定 --------------------
    if (-1 == bind(listenfd, (struct sockaddr *)&myaddr, sizeof(myaddr)))
    {
        perror("bind");
        exit(-1);
    }

    //------------------ 监听 --------------------
    if (-1 == listen(listenfd, 5))
    {
        perror("listen");
        exit(-1);
    }

    len = sizeof(peeraddr);
    while (1)
    {
        //------------------ accept 阻塞 --------------------
        if ((connfd = accept(listenfd, (struct sockaddr *)&peeraddr, &len)) == -1)
        {
            perror("accept");
            exit(-1);
        }

        printf("from %s : %d\n", inet_ntoa(peeraddr.sin_addr) ,
                ntohs(peeraddr.sin_port));

        if ((pid = fork()) == -1) // 连接成功后创建子进程 来完成收发工作
        {
            perror("fork");
            exit(-1);
        }

        if (pid == 0) // 子进程
        {
            close(listenfd);
            while (1)
            {
                bzero(buf, sizeof(buf));
                n = recv(connfd, buf, N, 0);//read(connfd, buf, N);
                printf("n=%d buf=%s", n, buf);
                if (n == 0)
                    break;
                send(connfd, buf, n, 0); //write(connfd, buf, n);
            }
            close(connfd);
            exit(0);
        }
        else
            close(connfd); //父进程关闭 连接描述符
    }


    return 0;
}