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


void signalDeal(int signum)
{
    wait(NULL);
}

int main()
{
    signal(SIGCHLD, signalDeal);
    int listen_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if(listen_fd < 0)
    {
        perror("socket");
        return 0;
    }

    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(47000);
    addr.sin_addr.s_addr = inet_addr("0.0.0.0");
    int ret =  bind(listen_fd, (struct sockaddr*)&addr, sizeof(addr));
    if(ret < 0)
    {
        perror("bind");
        return 0;
    }

    ret = listen(listen_fd, 6);
    if(ret < 0)
    {
        perror("listen");
        return 0;
    }

    //收发消息
    //
    while(1)
    {
        struct sockaddr_in cli_addr;
        socklen_t cli_addr_len = sizeof(cli_addr);
        int new_sockfd = accept(listen_fd, (struct sockaddr*)&cli_addr, &cli_addr_len);
        if(new_sockfd < 0)
        {
            continue;
        }

        pid_t pid = fork();
        if(pid < 0)
        {
            close(new_sockfd);
            continue;
        }
        else if(pid == 0)
        {
            //子进程
            close(listen_fd);
            //收发消息
            while(1)
            {
                char buf[1024] = {0};
                int recv_size = recv(new_sockfd, buf, sizeof(buf) - 1, 0);
                if(recv_size < 0)
                {
                    perror("recv");
                    continue;
                }
                else if(recv_size == 0)
                {
                    //客户端将连接关闭了
                    printf("perr shutdown!\n");
                    close(new_sockfd);
                    return 0;
                }
                printf("[%s]:[%d] say: [%s]\n",inet_ntoa(cli_addr.sin_addr), ntohs(cli_addr.sin_port), buf);

                memset(buf, '\0', sizeof(buf));

                //发送消息：
                //[客户端IP]:[客户端端口] I am server, I recv your msg
                sprintf(buf, "[%s]:[%d] I am server, I recv your msg",inet_ntoa(cli_addr.sin_addr), ntohs(addr.sin_port));

                send(new_sockfd, buf, strlen(buf), 0);
            }
        }
        else
        {
            close(new_sockfd);
        }
        
    }
    return 0;
}