C语言：自己编写的简易ftp客户端，包含（列表，进入目录，上传文件，下载文件，删除文件）功能

//简易ftp客户端#include <stdio.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <pthread.h>

#include <sys/stat.h>

#include <fcntl.h>

typedef struct sockaddr* sockaddrp;

//命令传输

int sockfd;

//数据传输

int sockfd1;

char buf[4096] = {};

//地址

char buf1[4096] = {};

//帐号、密码

char buf2[4096] = {};

//存放命令名

char tem1[255] = {};

//存放文件名

char tem2[255] = {};

struct sockaddr_in new_addr = {AF_INET};

void func()

{

	sprintf(buf,"PASV\n");

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	int a[4];

    int b[2];

    printf("%s\n",buf);

    sscanf(buf,"227 Entering Passive Mode (%d,%d,%d,%d,%d,%d)",&a[0],&a[1],&a[2],&a[3],&b[0],&b[1]);

    int msg = b[0]*256+b[1];

	sockfd1 = socket(AF_INET,SOCK_STREAM,0);

	new_addr.sin_port = htons(msg);

	new_addr.sin_addr.s_addr = inet_addr("192.168.6.66");

	connect(sockfd1,(sockaddrp)&new_addr,sizeof(new_addr));

}

//目录

void ls_run()

{

	sprintf(buf,"LIST\n");	

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd1,buf,sizeof(buf),0);

	printf("server:%s\n",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server:%s\n",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server:%s\n",buf);

}

//进入目录

void cd_run()

{

//-----------------------------------------------------

	sprintf(buf,"CWD %s\n",tem2);	

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	sprintf(buf,"PWD\n");	

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd1,buf,sizeof(buf),0);

	printf("server1:%s",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server2:%s\n",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server3:%s\n",buf);

	sprintf(buf1,"%s",buf);

	func();	

//-------------------------------------------------------	

	sprintf(buf,"LIST\n");	

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd1,buf,sizeof(buf),0);

	printf("%s",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server1:%s\n",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server2:%s\n",buf);

}

//下载

void get_run()

{

	func();

	sprintf(buf,"RETR %s\n",tem2);	

	send(sockfd,buf,strlen(buf),0);

	printf("%s",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd1,buf,sizeof(buf),0);

	int tmp=sizeof(new_addr);

	int fd = open(tem2,O_WRONLY|O_CREAT|O_TRUNC,0644);

	write(fd,buf,strlen(buf));

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("%s",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	close(fd);

}

//上传

void put_run()

{

	char inf[1024] = {};

	func();

	int fd = open(tem2,O_RDONLY);

	read(fd,inf,strlen(buf));

	close(fd);

	sprintf(buf,"STOR %s\n",tem2);	

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("%s",buf);

	sprintf(buf,"%s\n",inf);	

	send(sockfd1,buf,sizeof(buf),0);

	close(sockfd1);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("%s",buf);

}

//删除

void delete_run()

{

	func();

	sprintf(buf,"DELE %s\n",tem2);

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("%s",buf);

//-------------------------------------------------

	sprintf(buf,"LIST\n");	

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd1,buf,sizeof(buf),0);

	printf("%s",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server1:%s\n",buf);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server2:%s\n",buf);

}

//登陆

void login(void)

{

	recv(sockfd,buf,sizeof(buf),0);

	printf("server:%s",buf);

//用户帐号输入

	printf("输入用户名:");

	gets(buf2);

	sprintf(buf,"%s %s\n","USER",buf2);

	//sprintf(buf,"USER EOS1806\n");

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	//printf("server:%s",buf);

//用户密码输入

	printf("输入密码:");

	gets(buf2);

	sprintf(buf,"%s %s\n","PASS",buf2);

	//sprintf(buf,"PASS iqot1806\n");

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server:%s",buf);

	sprintf(buf,"SYST\n");

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server:%s",buf);

	sprintf(buf,"FEAT\n");

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("server:%s",buf);

	sprintf(buf,"OPTS UTF8 ON\n");

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("%s",buf);

	sprintf(buf,"PWD\n");

	send(sockfd,buf,strlen(buf),0);

	bzero(buf,sizeof(buf));

	recv(sockfd,buf,sizeof(buf),0);

	printf("%s",buf);

//功能

	while(1)

	{	

		printf("ftp> ");

		//获取命令	

		gets(buf);

		//命令分支

		if(!strcmp(buf,"ls"))

		{

			func();

			ls_run();

			close(sockfd1);

			continue;

		}

		if(!strcmp(buf,"bye"))

		{

			break;	

		}

		sscanf(buf,"%s %s",tem1,tem2);

		if(!strcmp(tem1,"cd") )

		{	

			cd_run();

			close(sockfd1);

			continue;

		}

		if(!strcmp(tem1,"get"))

		{

			get_run();

			close(sockfd1);

			continue;

		}

		if(!strcmp(tem1,"put"))

		{

			put_run();

			continue;

		}

		if(!strcmp(tem1,"delete"))

		{

			delete_run();

			close(sockfd1);

			continue;

		}

	}

}

//主函数

int main(int argc,char* argv[])

{	

	//socket

	sockfd = socket(AF_INET,SOCK_STREAM,0);

	if(0 > sockfd)

	{

		perror("socket");

		return -1;

	}

	struct sockaddr_in addr = {AF_INET};

	addr.sin_port = htons(21);

	addr.sin_addr.s_addr = inet_addr(argv[1]);

	int ret = connect(sockfd,(sockaddrp)&addr,sizeof(addr));

	if(0 > ret)

	{

		perror("connect");

		return -1;

	}

	login();

	close(sockfd);

}

原文地址：https://www.cnblogs.com/gzk1171848896/p/9426935.html