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发信人: jjk (UNIX+C+XML+?? 傻了?), 信区: Linux
标 题: 一个使用ftp协议的程序片段 guru (转寄)[转载]
发信站: 荔园晨风BBS站 (Thu Apr 25 10:25:39 2002), 转信
【 以下文字转载自 jjk 的信箱 】
【 原文由 jjk.bbs@apue.dhs.org 所发表 】
judite
(stranger)
07/17/01 08:01 PM
ftp c programming
请问PORT指令怎么用啊，我看了rfc，很简单还没man说的明了呢，
man里说PORT 127,0,0,1,192,0之后server会联接到client的指定端口，
但我用netstat没发现有这样一个联接啊。是不是还需要执行什么指令？谢谢！
astonia
(member)
11/13/00 11:07 AM
我提供一个使用ftp协议的程序片断,已经稳定运行了10个月.
ftpapi.c:
#include <signal.h>
#include <stdarg.h>
#include <errno.h>
#include "ftpapi.h"
#include "rdwr.h"
const response_t response_err = RESPONSE_ERR;
const response_t response_empty = RESPONSE_EMPTY;
int read_line(buf_t *buf,char *buff,int maxlen){
char ch;
int n,rc;
for ( n = 0; n < maxlen; ) {
if ((rc = read_1_byte(buf,&buff[n])) == 1) {
if (buff[n++] == '\n') break;
} else if (!rc) {
if (n == 0) return (0);
else break;
} else return -1;
}
buff[n-1] = 0;
return n;
}
int open_data_channel(ftp_t *ftp_info){
struct sockaddr_in servaddr;
int so_reuseaddr = 1;
size_t servaddr_size = sizeof(servaddr);
/* socket */
if ((ftp_info->data_channel_sockfd = socket(AF_INET,SOCK_STREAM,0))< 0)
return -1;
/* set reuse address */
if(setsockopt(ftp_info->data_channel_sockfd,SOL_SOCKET,SO_REUSEADDR,&so_
reuseaddr,sizeof(so_reuseaddr)) < 0) {
(void) close(ftp_info->data_channel_sockfd);
return -1;
}
/* set servaddr */
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
/* bind, let kernel choose the port */
if (bind(ftp_info->data_channel_sockfd,(SA *)&servaddr,servaddr_size)== -
1) {
(void) close(ftp_info->data_channel_sockfd);
return -1;
}
/* listen to the port as a server*/
if (listen(ftp_info->data_channel_sockfd,SOMAXCONN) == -1) {
(void) close(ftp_info->data_channel_sockfd);
return -1;
}
/* get port no choosed by kernel */
if(getsockname(ftp_info->data_channel_sockfd,(SA*)&servaddr,&servaddr_siz
e) == -1) {
(void) close(ftp_info->data_channel_sockfd);
return -1; }
//**
ftp_info->data_port = ntohs(servaddr.sin_port);
return ftp_info->data_channel_sockfd;
/* return socketdescriptor */
}
int ftp_command(ftp_t *ftp_info,const char *fmt,...){
va_list ap;
char cmdline[MAXLINESIZE], recvline[MAXLINESIZE];
int n = 0;
size_t cmdlen;
/* form command line */
va_start(ap,fmt);
/* reserve the space of \r\n\0 */ vsnprintf(cmdline,sizeof(cmdline)-3,f
mt,ap);
va_end(ap);
(void) strcat(cmdline,"\r\n");
printf(cmdline);
/* command length */
cmdlen = strlen(cmdline);
/* send cmd to ftpd */
begin_send_cmd:
if ((n=write(ftp_info->command_channel_sockfd,&cmdline[0]+n,cmdlen)) < 0)
{
/* interrupted by signal */
/*
if (errno == EINTR) {
n = 0;
goto begin_send_cmd; }
*/
ftp_info->response = response_err;
return -1;
/* send cmd to ftpd failed */
} if (n < cmdlen) {
/* send command incompletely */
cmdlen -= n;
/* resend from the break point */
goto begin_send_cmd; }
/* get response */
get_response(ftp_info);
return 0;
/* succeed */
}
int connect_to_ftpd(ftp_t *ftp_info,const char *ip,u_short port){ struct s
ockaddr_in servaddr;
struct hostent *hp;
int n;
int errno_save;
char recvline[MAXLINESIZE];
size_t servaddr_size = sizeof(servaddr);
bzero(ftp_info,sizeof(ftp_t));
ftp_info->server_port = port;
/* socket command channel */
if ((ftp_info->command_channel_sockfd=socket(AF_INET,SOCK_STREAM,0)) < 0)
return -1;
/* set zero to servaddr */
bzero(&servaddr,servaddr_size);
/* set family to AF_INET */
servaddr.sin_family = AF_INET;
/* change port to network byte order */
servaddr.sin_port = htons(port);
/* get host by name or ip is an IP address presentation */
if ((hp = gethostbyname(ip)) == NULL) {
/* ip is an IP */
if ((servaddr.sin_addr.s_addr = inet_addr(ip)) <= 0) {
errno_save = errno;
(void) close(ftp_info->command_channel_sockfd);
errno = errno_save;
return -1;
}
} else {
/* ip is an alias */
(void)memcpy(&servaddr.sin_addr,hp->h_addr_list[0],sizeof(servaddr.sin
_addr));
}
/* connect to ftp server command channel */
if (connect(ftp_info->command_channel_sockfd,(SA*)&servaddr,servaddr_size
) < 0) {
errno_save = errno;
(void) close(ftp_info->command_channel_sockfd);
errno = errno_save;
return -1;
}
/* get local ip connect to ftp server */
if (getsockname(ftp_info->command_channel_sockfd,(SA*)&servaddr,&servaddr
_size) == -1) {
errno_save = errno;
(void) close(ftp_info->command_channel_sockfd);
errno = errno_save;
return -1;
}
ftp_info->local_ip = servaddr.sin_addr.s_addr;
/* get response from ftp server */
get_response(ftp_info);
if (ftp_info->response.primary_code != 2) {
errno_save = errno;
(void) close(ftp_info->command_channel_sockfd);
errno = errno_save;
return -1;
/* fail */
} else {
return 0;
/* succeed */
}
}
void get_response(ftp_t *ftp_info){
int n;
buf_t buf;
/* init buf */
init_buf(&buf,ftp_info->command_channel_sockfd);
/* get the response message from ftpd */
n =read_line(&buf,&ftp_info->response_line[0],sizeof(ftp_info->response_l
ine)-1);
if (n < 0) {
ftp_info->response = response_err;
(void) destroy_buf(&buf);
return;
/* read socket failed */
}
if (!n) {
ftp_info->response = response_empty;
(void) destroy_buf(&buf);
return;
/* nothing read, socket closed */
}printf("%s\n",ftp_info->response_line);
ftp_info->response.primary_code = ftp_info->response_line[0] - '0';
/* primary code */
ftp_info->response.return_code = atoi(ftp_info->response_line);
/* get response code */
if (strlen(ftp_info->response_line) < 4 ||ftp_info->response_line[3] != '
-') {
(void) destroy_buf(&buf);
return;
/* single line response */
}
/* handle multi-line responses */
while (n) {
/* sth else to read from socket*/
n =read_line(&buf,&ftp_info->response_line[0],sizeof(ftp_info->respons
e_line)-1);
if (n < 0) {
ftp_info->response = response_err;
(void) destroy_buf(&buf);
return;
/* read socket failed */
}printf("%s\n",ftp_info->response_line);
if (strlen(ftp_info->response_line) > 3 &&ftp_info->response_line[3] =
= ' '
&& ftp_info->response.return_code ==atoi(ftp_info->response_line))
{
(void) destroy_buf(&buf);
return;
/* finish reading */
}
}
/* should not reach the next line
* because when n == 0, it means the socket is closed by other end
*/
strcat(ftp_info->response_line,"\n");
(void) destroy_buf(&buf);
return;
/* succeed */
}
int close_command_channel(ftp_t *ftp_info){
return close(ftp_info->command_channel_sockfd);}intclose_data_channel(ftp
_t *ftp_info){
return close(ftp_info->data_channel_sockfd);
}
ftpapi.h:
#ifndef _CS_FTPAPI_H_
#define _CS_FTPAPI_H_
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <inttypes.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
/* ftp server return codes */
#define FTPD_USERUNKOWN 530
/* user unkown */
#define FTPD_READY 220
/* ftp server ready */
#define FTPD_USERFIRST 503
/* login with USER first */
#define FTPD_BYE 221
/* goodbye */
#define FTPD_OK 200
/* command successful */
#define FTPD_REQPASS 331
/* password required */
#define FTPD_LOGIN 230
/* user logged in */
#define FTPD_PWD 257
/* xx is current directory */
#define FTPD_CWD 250
/* CWD command successful */
#define FTPD_NOENT 550
/* no such file or dir */
#define FTPD_HELP 214
/* HELP message */
#define FTPD_CMDUNKOWN 500
/* command not understood */
#define FTPD_NOTIMPLE 502
/* command not implemented */
#define FTPD_CANTCONN 425
/* can't build data connection*/
#define FTPD_ASCCONN 150
/* data connection for xx */
#define FTPD_TRANCOMP 226
/* transfer complete */
#define FTPD_ABOR 225
/* ABOR command successful */
/* max size of response line */
#define MAXLINESIZE 1024
/* convinience for programming */
#define SA struct sockaddr
/* define the data structure of the ftp server return code */
/* primary_code stores the primary code which indicates the
* primary result from ftp server * return_code is the full 3-digit result
* constant {-1, -1} indicates error occured,
* and {0, 0} indicates empty response(maybe socket closed).
*/
#define RESPONSE_ERR {-1, -1}
--
※ 转寄:·UNIX编程 apue.dhs.org·[FROM: 210.39.3.50]
--
※ 转载:·荔园晨风BBS站 bbs.szu.edu.cn·[FROM: 192.168.0.146]
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