Linux poll服务器

最新推荐文章于 2023-08-01 20:15:37 发布

Dakuan_chen

最新推荐文章于 2023-08-01 20:15:37 发布

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分类专栏： linux网络编程

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本文介绍了一个简易的TCP服务器实现，该服务器使用C语言编写，并利用poll机制处理多个客户端连接请求。服务器通过监听指定的IP地址和端口接收客户端连接，能够接受新连接、读取客户端消息并发送回应。

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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <poll.h>

#define MAX_POLL_SIZE 128

static void usage(char* arg)
{
    printf("Usage:%s[local_ip][local_port]\n",arg);
}

int starup(const char* ip,int port)
{
    int sock = socket(AF_INET,SOCK_STREAM,0);
    if(sock < 0)
    {
        perror("socket");
        exit(2);
    }

    struct sockaddr_in server;
    server.sin_family = AF_INET;
    server.sin_port = htons(port);
    server.sin_addr.s_addr = inet_addr(ip);
    int opt = 1;
    setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));

    if(bind(sock,(struct sockaddr*)&server,sizeof(server)) < 0)
    {
        perror("bind");
        exit(3);
    }

    if(listen(sock,5) < 0)
    {
        perror("listen");
        exit(4);
    }

    return sock;
}

int main(int argc,char* argv[])
{
    if(3 != argc)
    {
        usage(argv[0]);
        return 1;
    }

    int listen_sock = starup(argv[1],atoi(argv[2]));
    struct pollfd fds[MAX_POLL_SIZE];
    fds[0].fd = listen_sock;
    fds[0].events = POLLIN;
    int i = 1;
    for(;i<MAX_POLL_SIZE;++i)
    {
        fds[i].fd=-1;
    }
    while(1)
    {
        int num = poll(fds,MAX_POLL_SIZE,-1);
        switch(num)
        {
        case 0:
            printf("nothing ready\n");
            break;
        case -1:
            perror("poll");
            break;
        default:
            {
                for(i = 0;i < MAX_POLL_SIZE; ++ i)
                {
                    if(fds[i].fd == -1)
                        continue;
                    else if(i == 0 && fds[0].revents & POLLIN)
                    {
                        struct sockaddr_in client;
                        socklen_t len = sizeof(client);
                        int new_sock = accept(listen_sock,(struct sockaddr*)&client,&len); 
                        if(new_sock < 0)
                        {
                            perror("accept");
                            continue;
                        }

                        printf("get a new client:%s %d\n",inet_ntoa(client.sin_addr),ntohs(client.sin_port));
                        int j = 1;
                        for(;j < MAX_POLL_SIZE; ++j)
                        {
                            if(fds[j].fd == -1)
                                break;
                        }

                        if(j < MAX_POLL_SIZE)
                        {
                            fds[j].fd = new_sock;
                            fds[j].events = POLLIN | POLLOUT;
                        }
                        else
                        {
                            printf("servet is busy!!\n");
                            close(new_sock);
                        }
                    }
                    else if(fds[i].revents & POLLIN)
                    {
                        char buf[1024];
                        ssize_t s = read(fds[i].fd,buf,sizeof(buf)-1);
                        if(s < 0)
                        {
                            perror("read ");
                            close(fds[i].fd);
                            fds[i].fd=-1;
                            continue;
                        }
                        else if(s == 0)
                        {
                            printf("client quit!!\n");
                            close(fds[i].fd);
                            fds[i].fd=-1;
                            continue;
                        }
                        buf[s]=0;
                        printf("%s\n",buf);
                    }
                    else if(fds[i].revents & POLLOUT) {
                        char* buf = "hello word";
                        write(fds[i].fd,buf,strlen(buf));
                        close(fds[i].fd);
                        fds[i].fd=-1;
                        printf("server close client\n");
                    }
                }//for
            }//default
        }//switch
    }//while

    return 0;
}