Linux下C编写基本的多线程socket服务器

不想多说什么，会搜这些东西的都是想看代码的吧。

一开始不熟悉多线程的时候还在想怎么来控制一个线程的结束，后来发现原来有pthread_exit()函数可以直接在线程函数内部调用结束这个线程。

开始还想初始化一个pthread_t thread_fd[MAX]数组来存储开启的线程，然后用一个栈存储那些未分配的数组元素（thread_fd[index]=0）的index，跟缓存的思维相似，不过实在是想多了。

废话不多说，直接上代码，服务器和客户端都已经编译通过，正常运行，有基本的容错能力，不过也只是最基本的。

服务器：

/*
 * multi_thread_socket_server.c
 *
 *  Created on: Mar 14, 2014
 *      Author: nerohwang
 */
#include<stdlib.h>
#include<pthread.h>
#include<sys/socket.h>
#include<sys/types.h>       //pthread_t , pthread_attr_t and so on.
#include<stdio.h>
#include<netinet/in.h>      //structure sockaddr_in
#include<arpa/inet.h>       //Func : htonl; htons; ntohl; ntohs
#include<assert.h>          //Func :assert
#include<string.h>          //Func :memset
#include<unistd.h>          //Func :close,write,read
#define SOCK_PORT 9988
#define BUFFER_LENGTH 1024
#define MAX_CONN_LIMIT 512     //MAX connection limit

static void Data_handle(void * sock_fd);   //Only can be seen in the file

int main()
{
    int sockfd_server;
    int sockfd;
    int fd_temp;
    struct sockaddr_in s_addr_in;
    struct sockaddr_in s_addr_client;
    int client_length;

    sockfd_server = socket(AF_INET,SOCK_STREAM,0);  //ipv4,TCP
    assert(sockfd_server != -1);

    //before bind(), set the attr of structure sockaddr.
    memset(&s_addr_in,0,sizeof(s_addr_in));
    s_addr_in.sin_family = AF_INET;
    s_addr_in.sin_addr.s_addr = htonl(INADDR_ANY);  //trans addr from uint32_t host byte order to network byte order.
    s_addr_in.sin_port = htons(SOCK_PORT);          //trans port from uint16_t host byte order to network byte order.
    fd_temp = bind(sockfd_server,(struct scokaddr *)(&s_addr_in),sizeof(s_addr_in));
    if(fd_temp == -1)
    {
        fprintf(stderr,"bind error!\n");
        exit(1);
    }

    fd_temp = listen(sockfd_server,MAX_CONN_LIMIT);
    if(fd_temp == -1)
    {
        fprintf(stderr,"listen error!\n");
        exit(1);
    }

    while(1)
    {
        printf("waiting for new connection...\n");
        pthread_t thread_id;
        client_length = sizeof(s_addr_client);

        //Block here. Until server accpets a new connection.
        sockfd = accept(sockfd_server,(struct sockaddr_*)(&s_addr_client),(socklen_t *)(&client_length));
        if(sockfd == -1)
        {
            fprintf(stderr,"Accept error!\n");
            continue;                               //ignore current socket ,continue while loop.
        }
        printf("A new connection occurs!\n");
        if(pthread_create(&thread_id,NULL,(void *)(&Data_handle),(void *)(&sockfd)) == -1)
        {
            fprintf(stderr,"pthread_create error!\n");
            break;                                  //break while loop
        }
    }

    //Clear
    int ret = shutdown(sockfd_server,SHUT_WR); //shut down the all or part of a full-duplex connection.
    assert(ret != -1);

    printf("Server shuts down\n");
    return 0;
}

static void Data_handle(void * sock_fd)
{
    int fd = *((int *)sock_fd);
    int i_recvBytes;
    char data_recv[BUFFER_LENGTH];
    const char * data_send = "Server has received your request!\n";

    while(1)
    {
        printf("waiting for request...\n");
        //Reset data.
        memset(data_recv,0,BUFFER_LENGTH);

        i_recvBytes = read(fd,data_recv,BUFFER_LENGTH);
        if(i_recvBytes == 0)
        {
            printf("Maybe the client has closed\n");
            break;
        }
        if(i_recvBytes == -1)
        {
            fprintf(stderr,"read error!\n");
            break;
        }
        if(strcmp(data_recv,"quit")==0)
        {
            printf("Quit command!\n");
            break;                           //Break the while loop.
        }
        printf("read from client : %s\n",data_recv);
        if(write(fd,data_send,strlen(data_send)) == -1)
        {
            break;
        }
    }

    //Clear
    printf("terminating current client_connection...\n");
    close(fd);            //close a file descriptor.
    pthread_exit(NULL);   //terminate calling thread!
}

外加客户端:

/*
 * socket_client.c
 *
 *  Created on: Mar 15, 2014
 *      Author: nerohwang
 */
#include<stdlib.h>
#include<sys/socket.h>
#include<sys/types.h>       //pthread_t , pthread_attr_t and so on.
#include<stdio.h>
#include<netinet/in.h>      //structure sockaddr_in
#include<arpa/inet.h>       //Func : htonl; htons; ntohl; ntohs
#include<assert.h>          //Func :assert
#include<string.h>          //Func :memset
#include<unistd.h>          //Func :close,write,read
#define SOCK_PORT 9988
#define BUFFER_LENGTH 1024
int main()
{
    int sockfd;
    int tempfd;
    struct sockaddr_in s_addr_in;
    char data_send[BUFFER_LENGTH];
    char data_recv[BUFFER_LENGTH];
    memset(data_send,0,BUFFER_LENGTH);
    memset(data_recv,0,BUFFER_LENGTH);

    sockfd = socket(AF_INET,SOCK_STREAM,0);       //ipv4,TCP
    if(sockfd == -1)
    {
        fprintf(stderr,"socket error!\n");
        exit(1);
    }

    //before func connect, set the attr of structure sockaddr.
    memset(&s_addr_in,0,sizeof(s_addr_in));
    s_addr_in.sin_addr.s_addr = inet_addr("127.0.0.1");      //trans char * to in_addr_t
    s_addr_in.sin_family = AF_INET;
    s_addr_in.sin_port = htons(SOCK_PORT);

    tempfd = connect(sockfd,(struct sockaddr *)(&s_addr_in),sizeof(s_addr_in));
    if(tempfd == -1)
    {
        fprintf(stderr,"Connect error! \n");
        exit(1);
    }

    while(1)
    {
        printf("Please input something you wanna say(input \"quit\" to quit):\n");
        gets(data_send);
        //scanf("%[^\n]",data_send);         //or you can also use this
        tempfd = write(sockfd,data_send,BUFFER_LENGTH);
        if(tempfd == -1)
        {
            fprintf(stderr,"write error\n");
            exit(0);
        }

        if(strcmp(data_send,"quit") == 0)  //quit,write the quit request and shutdown client
        {
            break;
        }
        else
        {
            tempfd = read(sockfd,data_recv,BUFFER_LENGTH);
            assert(tempfd != -1);
            printf("%s\n",data_recv);
            memset(data_send,0,BUFFER_LENGTH);
            memset(data_recv,0,BUFFER_LENGTH);
        }
    }

    int ret = shutdown(sockfd,SHUT_WR);       //or you can use func close()--<unistd.h> to close the fd
    assert(ret != -1);
    return 0;
}