Linux网络编程6——使用TCP实现文件服务器

当客户端连接上服务器后，服务器会将相应文件传输给客户端，实现文件下载。

服务器端，主进程负责listen。循环内，主进程每从任务请求队列中accept出一个请求，就fork出孙子完成文件传输。注意：如果只是fork出儿子，那么主进程就得wait儿子，这样的话，只有当给一个客户端传完文件后才能下一个。

server端

/*************************************************************************  > File Name: server.c  > Author: KrisChou  > Mail:zhoujx0219@163.com   > Created Time: Thu 28 Aug 2014 09:40:32 PM CST ************************************************************************/#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <unistd.h>#include <netdb.h>#define SNDSIZE 1024*1024 //1M，注意如果栈空间(可以设置的)没这么大，就用堆空间#define FILE_NAME  "a.rmvb"int main(int argc,char* argv[])// exe config{    /* 从配置文件中读取服务器联系方式：ip以及端口号 */    int fd_conf ;    fd_conf = open(argv[1], O_RDONLY) ;    FILE* fp_conf = fdopen(fd_conf, "r"); //秀一下fdopen函数，文件描述符转换为文件指针 fdopen(int fd, const char *mode)    char my_ip[32]="";    int my_port ;    fscanf(fp_conf, "%s%d", my_ip, &my_port);    close(fd_conf);    fclose(fp_conf);    /* 创建服务器的监听socket端口 */    int fd_listen    fd_listen = socket(AF_INET, SOCK_STREAM, 0);    if(fd_listen == -1)    {        perror("socket");    }    /* 为服务器socket端口绑定联系方式，以便让客户端connect */        struct sockaddr_in  server_addr ;    memset(&server_addr, 0, sizeof(server_addr));    server_addr.sin_family = AF_INET ;    server_addr.sin_port = htons(my_port);    server_addr.sin_addr.s_addr  = inet_addr(my_ip);    if(-1 == bind(fd_listen, (struct sockaddr *)&server_addr, sizeof(server_addr)) )    {        perror("bind");        close(fd_listen);        exit(1);    }    /* listen */    if(-1 == listen(fd_listen, 5))    {        perror("listen");        close(fd_listen);        exit(1);    }        /* accept */    int fd_client;  /* 客户端socket端口的另一头 */    struct sockaddr_in client_addr ; /* 客户端联系方式，以accept函数的传出参数给出 */    int len ;    memset(&client_addr, 0, sizeof(client_addr));    len = sizeof(client_addr);    while(1)    {        fd_client = accept(fd_listen, (struct sockaddr *)&client_addr, &len);        if(fd_client == -1)         {            continue ;        }        PRintf("a client connect ! ip:port  %s:%d/n",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));        if(fork() == 0)        {            close(fd_listen); //对于子进程和孙子进程都不需要listen端口，直接关闭。            if(fork() == 0)            {                int fd_file = open(FILE_NAME, O_RDONLY); //打开客户端要下载的文件                char buf[SNDSIZE] ;                int snd_cnt = 0 ;                int readn ;                /* 从文件中读取数据,并发送给客户端 */                while(memset(buf, 0,SNDSIZE ), (readn = read(fd_file,buf, SNDSIZE)) > 0)                {                        if(send(fd_client, buf, readn, 0) != readn)                        {                            printf("send error! /n");                        }                        snd_cnt ++ ;                }                printf("send over: %d /n", snd_cnt);                close(fd_file);                close(fd_client);                exit(0);            }            close(fd_client);            exit(0);        }        close(fd_client);        wait(NULL) ;    }    return 0 ;}

client端

/*************************************************************************    > File Name: client.c    > Author: KrisChou    > Mail:zhoujx0219@163.com     > Created Time: Thu 28 Aug 2014 11:59:20 PM CST ************************************************************************/#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <unistd.h>#include <netdb.h>#define SNDSIZE 1024*1024#define SERVER_PORT 6080 // 服务器端口int main(int argc, char *argv[]) EXE IP{    /* socket */    int fd_client;    fd_client = socket(AF_INET, SOCK_STREAM, 0);    if(fd_client == -1)    {        perror("socket");        exit(1);    }    /* 存放所连服务器信息的结构体 */    struct sockaddr_in server_addr;    memset(&server_addr,0,sizeof(server_addr));    server_addr.sin_family = AF_INET;    server_addr.sin_port = htons(SERVER_PORT);    server_addr.sin_addr.s_addr = inet_addr(argv[1]);    /* connect */    while(connect(fd_client, (struct sockaddr *)&server_addr,sizeof(server_addr)) == -1)    {        /* 当connect返回-1时，说明服务器还没有启动 */        sleep(1);        printf("connecting... /n");    }    printf("connect success! /n");    int fd_write = open("txt", O_WRONLY | O_CREAT);//下载的内容写入本地文件中    char buf[SNDSIZE];    int readn;    int recv_cnt = 0;    while(memset(buf,0,SNDSIZE),(readn = recv(fd_client,buf,SNDSIZE,0)) > 0)    {        write(fd_write,buf,readn);        recv_cnt++;    }    printf("recv over: %d /n", recv_cnt);    close(fd_write);    close(fd_client);    return 0;}