C语言 简单的文件下载器

代码中的ip地址写的都是回环测试ip，如果要在两个电脑之间，请修改代码中ip地址一行。然后服务器中的文件夹路径改为您的。
写的不好，您多担待。

服务器部分：

#include <stdio.h>#include <stdlib.h>#include <dirent.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <sys/socket.h>#include <string.h>#include <arpa/inet.h>#include <netinet/in.h>#include <unistd.h>char buf[64] = "\0";DIR *dir;struct dirent *p;int listenfd, connfd;int fd;int ret;void list(){    dir = opendir("/home/fs/17091/class");    if (NULL == dir)    {        perror("opendir");        exit(0);    }    while((p = readdir(dir)) != NULL)     {        bzero(buf,sizeof(buf));        if (0 == strncmp(".",p->d_name,1))        continue;        strcpy(buf,p->d_name);        send(connfd,buf,64,0);    }    #if 1    bzero(buf,sizeof(buf));    strcpy(buf,"####");    send(connfd,buf,4,0);    #endif    closedir(dir);    return;}void download(char buf[]){    char name[64] = "/home/fs/17091/class/";    char *p = buf+4;    int n;    strcat(name,p);    name[strlen(name)-1] = '\0';    fd = open(name,O_RDONLY);    if (-1 == fd)    {        close(connfd);        return;    }    while ((n = read(fd,buf,64)) > 0)    {        write(connfd,buf,n);        bzero(buf,sizeof(buf));    }    printf("传输完毕\n");    close(connfd);    close(fd);}void upload(char buf[]){    char msg[64] = "\0";    if (recv(connfd, msg, 64, 0) <= 0)    {        close(connfd);        return;    }    else    {    char name[64] = "/home/fs/17091/class/";    char *p = buf+4;    int n;    strcat(name,p);    name[strlen(name)-1] = '\0';    fd = open(name,O_WRONLY | O_CREAT | O_TRUNC,0666);    if (-1 == fd)    {        strcpy(buf,"fail");        send(connfd,buf,64,0);        return;    }    while ((n = read(connfd,buf,64)) > 0)    {        write(fd,buf,n);        bzero(buf,sizeof(buf));    }    printf("上传完毕\n");    close(connfd);    close(fd);    }}int main(int argc, const char *argv[]){    struct sockaddr_in seraddr, cliaddr;    socklen_t addrlen = sizeof(cliaddr);    //step 1:创建套接字接口    listenfd = socket(AF_INET, SOCK_STREAM, 0);    if (-1 == listenfd)    {        perror("socket");        return -1;    }    //step 2:绑定IP地址和端口号    memset(&seraddr, 0, sizeof(seraddr));    seraddr.sin_family = AF_INET;    seraddr.sin_port = htons(8888);    seraddr.sin_addr.s_addr = inet_addr("127.0.0.1");    ret = bind(listenfd, (struct sockaddr *)&seraddr, sizeof(seraddr));    if (-1 == ret)    {        perror("bind");        return -1;    }    //step 3:监听连接请求    ret = listen(listenfd, 5);    if (-1 == ret)    {        perror("listen");        return -1;    }    //step 4:接受连接请求    while(1)    {        connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &addrlen);        if(-1 == connfd)        {            perror("accept");            return -1;        }        printf("accept successfully, client ip = %s, port = %d\n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port));        while(1)        {            //接受数据            bzero(buf,sizeof(buf));            ret = recv(connfd, buf, sizeof(buf), 0);            if (-1 == ret)            {                perror("read");                return -1;            }            if (0 == strncmp("list",buf,4))            {                list();                break;             }            else if (0 == strncmp("get",buf,3))            {                download(buf);                break;             }            else if (0 == strncmp("put",buf,3))            {                upload(buf);                break;             }            else            break;        }        close(connfd);    }    close(listenfd);    return 0;}

客户端部分：

#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <sys/socket.h>#include <string.h>#include <arpa/inet.h>#include <netinet/in.h>#include <unistd.h>char buf[64] = "\0";int fd;int ret;int init_net(){    struct sockaddr_in seraddr;    int connfd;    //step 1: 创建套接字接口    connfd = socket(AF_INET, SOCK_STREAM, 0);    if(-1 == connfd)    {        perror("socket");        return -1;    }    //step 2: 发起连接请求    memset(&seraddr, 0, sizeof(seraddr));    seraddr.sin_family = AF_INET;    seraddr.sin_port = htons(8888);    seraddr.sin_addr.s_addr = inet_addr("127.0.0.1");    ret = connect(connfd, (struct sockaddr *)&seraddr, sizeof(seraddr));    if(-1 == ret)    {        perror("connect");        return -1;    }    return connfd;}void help(){    printf("hlep:显示客户端所有命令和说明\n");    printf("list:显示服务器端可下载文件列表\n");    printf("get+空格+文件名:下载文件\n");    printf("put+空格+文件名:上传文件\n");    printf("quit:退出客户端\n");}void list(){    int connfd;    connfd = init_net();    strcpy(buf,"list");    ret = send(connfd, buf, sizeof(buf), 0);        if(-1 == ret)    {        perror("send");        return;    }    while (1)    {        if ((recv(connfd,buf,64,0) > 0))        {            if (strncmp("####",buf,4) != 0)             printf("%s\n",buf);            else            break;        }    }    close(connfd);    return;}void download(char buf[]){    int connfd;    char msg[64] = "\0";    connfd = init_net();    send(connfd,buf,64,0);    if (recv(connfd,msg,64,0) <= 0)    {        printf("没有这个文件,无法下载\n");        close(connfd);        return;    }    else    {        int n;        char *p = buf+4;        char name[64] = "/home/fs/17091/play/download/";        strcat(name,p);        name[strlen(name)-1] = '\0';        fd = open(name,O_WRONLY | O_CREAT | O_TRUNC,0666);        if (-1 == fd)        {            perror("open");            return;        }        while ((n = read(connfd,buf,64)) > 0)        {            write(fd,buf,n);            bzero(buf,sizeof(buf));        }        printf("下载完成\n");        close(fd);        close(connfd);        return;    }}void upload(char buf[]){    int connfd;    connfd = init_net();    send(connfd,buf,64,0);    int n;    char *p = buf+4;    char name[64] = "/home/fs/17091/play/download/";    strcat(name,p);    name[strlen(name)-1] = '\0';    fd = open(name,O_RDONLY);    if (-1 == fd)    {        printf("没有这个文件，无法上传\n");        close(connfd);        return;    }    while ((n = read(fd,buf,64)) > 0)    {        write(connfd,buf,n);        bzero(buf,sizeof(buf));    }    printf("上传完成\n");    close(fd);    close(connfd);    return;}int main(int argc, const char *argv[]){    while (1)    {        system("clear");        printf("请输入选项，输入'help'查看帮助\n");        printf("input>>");        fgets(buf,sizeof(buf),stdin);        if (0 == strncmp("help",buf,4))        {            help();            printf("输入Enter键继续\n");            getchar();            continue;        }        if (0 == strncmp("list",buf,4))        {            list();            printf("输入Enter键继续\n");            getchar();            continue;        }        else if (0 == strncmp("get",buf,3))        {            printf("开始下载\n");            download(buf);            printf("输入Enter键继续\n");            getchar();            continue;        }        else if (0 == strncmp("put",buf,3))        {            printf("开始上传\n");            upload(buf);            printf("输入Enter键继续\n");            getchar();            continue;        }        else if (0 == strncmp("quit",buf,4))        {            printf("欢迎下次使用，祝您生活愉快\n");            break;        }        else        {            printf("输入有误，请输入Enter键继续\n");            getchar();            continue;        }    }    return 0;}