int get_transfer_fd(session_t* sess)
{
//check have received port or pasv command before
if(!port_active(sess) && !pasv_active(sess))
{
ftp_reply(sess, FTP_BADSENDCONN, "Use PORT or PASV first.");
return 0;
}
int ret = 1;
if(port_active(sess))
{
if(get_port_fd(sess) == 0)
ret = 0;
}
if(pasv_active(sess))
{
if(get_pasv_fd(sess) == 0)
ret = 0;
}
if(sess->port_addr)
{
free(sess->port_addr);
sess->port_addr = NULL;
}
if(ret)
start_data_alarm();
return ret;
}
int get_transfer_fd(session_t *pses)
{
int iret = 0;
//可能是主动模式，或者被动模式
//检测是否收到PORT命令或者PASV命令
if((port_active(pses) < 0) && (pasv_active(pses) < 0))
{
ftp_reply(pses->ctrl_fd, FTP_BADSENDCONN, "Use PORT or PASV first.");
iret = -1;
return iret;
}
//主动模式
if(port_active(pses) == 0)
{
//向nobody进程发送命令
priv_sock_send_cmd(pses->child_fd, PRIV_SOCK_GET_DATA_SOCK);
unsigned short port = ntohs(pses->port_addr->sin_port);
char *ip = inet_ntoa(pses->port_addr->sin_addr);
//发送port
priv_sock_send_int(pses->child_fd, (int)port);
//发送ip
priv_sock_send_buf(pses->child_fd, ip, strlen(ip));
//接收应答
char res = priv_sock_get_result(pses->child_fd);
if(res == PRIV_SOCK_RESULT_BAD)
{
iret = -1;
}
else if(res == PRIV_SOCK_RESULT_OK)
{
//接收文件描述符
pses->data_fd = priv_sock_recv_fd(pses->child_fd);
}
}
else if(pasv_active(pses) == 0)//被动模式
{
//发送命令给nobody进程，完成客户端和服务端的连接
priv_sock_send_cmd(pses->child_fd, PRIV_SOCK_PASV_ACCEPT);
//接收nobody进程的应答
char res = priv_sock_get_result(pses->child_fd);
if(res == PRIV_SOCK_RESULT_BAD)
{
iret = -1;
}
else if(res == PRIV_SOCK_RESULT_OK)
{
pses->data_fd = priv_sock_recv_fd(pses->child_fd);
}
}
//连接成功后，该内存空间就不需要了
if(pses->port_addr != NULL)
{
free(pses->port_addr);
pses->port_addr = NULL;
}
return iret;
}
static int
get_remote_transfer_fd(struct vsf_session* p_sess)
{
int remote_fd;
if (!pasv_active(p_sess) && !port_active(p_sess))
{
bug("neither PORT nor PASV active in get_remote_transfer_fd");
}
p_sess->abor_received = 0;
if (pasv_active(p_sess))
{
remote_fd = vsf_ftpdataio_get_pasv_fd(p_sess);
}
else
{
remote_fd = vsf_ftpdataio_get_port_fd(p_sess);
}
return remote_fd;
}
/**
*port_active - 检查主动模式是否被激活过
*@sess:会话结构体
*激活过返回1，没有激活过返回0
*/
int ftpproto::port_active(session_t* sess)
{//若主动模式被激活过，则有保存对等的地址，port结构体不为空
if (sess->port_addr != NULL)
{//主动模式处于激活的状态
if (pasv_active(sess))//被动模式也处于激活的状态
{//这种 状况是不允许的
LCWFTPD_LOG(ERROR,"both port and pasv are active");
}
return 1;
}
return 0;//没有激活过
}
int port_active(session_t* sess)
{
if(sess->port_addr)
{
if(pasv_active(sess))
{
fprintf(stderr, "both port and pasv are active.");
exit(EXIT_FAILURE);
}
return 1;
}
return 0;
}
/**
*get_transfer_fd - 创建数据连接,主动用connect，被动用accept
*@sess:会话结构体
*成功返回0，失败返回1
*/
int ftpproto::get_transfer_fd(session_t* sess)
{
//检测是否收到PORT或者PASV命令
//激活过是1
if (!port_active(sess) && !pasv_active(sess))//没有被激活过
{//两个都没有被激活过，要给个应答，若直接返回会使客户端阻塞
ftp_reply(sess,FTP_BADSENDCONN,"Use PORT or PASV first.");
return 1;//失败
}
int ret = 0;
if (port_active(sess))//主动模式，服务器创建数据套接字(bind 20端口)
{ //调用connect连接客户端IP与端口，建立数据连接
if (get_port_fd(sess))//获取主动模式的套接字
{//失败
ret = 1;
}
}
if (pasv_active(sess))//被动模式，使用accept
{
if (get_pasv_fd(sess))//获取被动模式的套接字
{//失败
ret = 1;
}
}
if (sess->port_addr)
{//之前调用过do_port了，数据连接用完就free
free(sess->port_addr);
sess->port_addr = NULL;
}
// if (ret)
// {
// //成功创建数据通道后就开启闹钟信号
// start_data_alarm();//重新安装SIGALRM信号，并启动闹钟
// }
return ret;//成功是0，失败是1
}
static int
port_active(struct vsf_session* p_sess)
{
int ret = 0;
if (p_sess->p_port_sockaddr != 0)
{
ret = 1;
if (pasv_active(p_sess))
{
bug("port and pasv both active");
}
}
return ret;
}
int port_active(session_t *pses)
{
if(pses->port_addr != NULL)
{
if(pasv_active(pses) == 0) //主被动模式不能同时处于激活状态
{
handle_error_str("both port and pasv are active.");
}
return 0;
}
else
{
return -1;
}
}
static void
handle_upload_common(struct vsf_session* p_sess, int is_append)
{
struct vsf_transfer_ret trans_ret;
int new_file_fd;
int remote_fd;
int retval;
filesize_t offset = p_sess->restart_pos;
p_sess->restart_pos = 0;
if (!pasv_active(p_sess) && !port_active(p_sess))
{
vsf_cmdio_write(p_sess, FTP_BADSENDCONN, "Use PORT or PASV first.");
return;
}
/* NOTE - actual file permissions will be governed by the tunable umask */
/* XXX - do we care about race between create and chown() of anonymous
* upload?
*/
if (p_sess->is_anonymous && !tunable_anon_other_write_enable)
{
new_file_fd = str_create(&p_sess->ftp_arg_str);
}
else
{
/* For non-anonymous, allow open() to overwrite or append existing files */
if (!is_append && offset == 0)
{
new_file_fd = str_create_overwrite(&p_sess->ftp_arg_str);
}
else
{
new_file_fd = str_create_append(&p_sess->ftp_arg_str);
}
}
if (vsf_sysutil_retval_is_error(new_file_fd))
{
vsf_cmdio_write(p_sess, FTP_UPLOADFAIL, "Could not create file.");
return;
}
/* Are we required to chown() this file for security? */
if (p_sess->is_anonymous && tunable_chown_uploads)
{
if (tunable_one_process_model)
{
vsf_one_process_chown_upload(p_sess, new_file_fd);
}
else
{
vsf_two_process_chown_upload(p_sess, new_file_fd);
}
}
if (!is_append && offset != 0)
{
/* XXX - warning, allows seek past end of file! Check for seek > size? */
vsf_sysutil_lseek_to(new_file_fd, offset);
}
remote_fd = get_remote_transfer_fd(p_sess);
if (vsf_sysutil_retval_is_error(remote_fd))
{
goto port_pasv_cleanup_out;
}
vsf_cmdio_write(p_sess, FTP_DATACONN,
"Ok to send data.");
vsf_log_start_entry(p_sess, kVSFLogEntryUpload);
str_copy(&p_sess->log_str, &p_sess->ftp_arg_str);
prepend_path_to_filename(&p_sess->log_str);
if (tunable_ascii_upload_enable && p_sess->is_ascii)
{
trans_ret = vsf_ftpdataio_transfer_file(p_sess, remote_fd,
new_file_fd, 1, 1);
}
else
{
trans_ret = vsf_ftpdataio_transfer_file(p_sess, remote_fd,
new_file_fd, 1, 0);
}
p_sess->transfer_size = trans_ret.transferred;
/* XXX - handle failure, delete file? */
retval = dispose_remote_transfer_fd(p_sess);
/* Log _after_ the blocking dispose call, so we get transfer times right */
if (trans_ret.retval == 0 && retval == 0)
{
vsf_log_do_log(p_sess, 1);
}
else
{
vsf_log_do_log(p_sess, 0);
}
port_pasv_cleanup_out:
port_cleanup(p_sess);
pasv_cleanup(p_sess);
vsf_sysutil_close(new_file_fd);
}
static void
handle_dir_common(struct vsf_session* p_sess, int full_details)
{
static struct mystr s_option_str;
static struct mystr s_filter_str;
static struct mystr s_dir_name_str;
static struct vsf_sysutil_statbuf* s_p_dirstat;
int remote_fd;
int dir_allow_read = 1;
struct vsf_sysutil_dir* p_dir = 0;
str_empty(&s_option_str);
str_empty(&s_filter_str);
/* By default open the current directory */
str_alloc_text(&s_dir_name_str, ".");
if (!pasv_active(p_sess) && !port_active(p_sess))
{
vsf_cmdio_write(p_sess, FTP_BADSENDCONN, "Use PORT or PASV first.");
return;
}
/* Do we have an option? Going to be strict here - the option must come
* first. e.g. "ls -a .." fine, "ls .. -a" not fine
*/
if (!str_isempty(&p_sess->ftp_arg_str) &&
str_get_char_at(&p_sess->ftp_arg_str, 0) == '-')
{
/* Chop off the '-' */
str_mid_to_end(&p_sess->ftp_arg_str, &s_option_str, 1);
/* A space will separate options from filter (if any) */
str_split_char(&s_option_str, &s_filter_str, ' ');
}
else
{
/* The argument, if any, is just a filter */
str_copy(&s_filter_str, &p_sess->ftp_arg_str);
}
if (!str_isempty(&s_filter_str))
{
/* First check - is it an outright directory, as in "ls /pub" */
p_dir = str_opendir(&s_filter_str);
if (p_dir != 0)
{
/* Listing a directory! */
str_copy(&s_dir_name_str, &s_filter_str);
str_free(&s_filter_str);
}
else
{
struct str_locate_result locate_result =
str_locate_char(&s_filter_str, '/');
if (locate_result.found)
{
/* Includes a path! Reverse scan for / in the arg, to get the
* base directory and filter (if any)
*/
str_copy(&s_dir_name_str, &s_filter_str);
str_split_char_reverse(&s_dir_name_str, &s_filter_str, '/');
/* If we have e.g. "ls /.message", we just ripped off the leading
* slash because it is the only one!
*/
if (str_isempty(&s_dir_name_str))
{
str_alloc_text(&s_dir_name_str, "/");
}
}
}
}
if (p_dir == 0)
{
/* NOTE - failure check done below, it's not forgotten */
p_dir = str_opendir(&s_dir_name_str);
}
/* Fine, do it */
remote_fd = get_remote_transfer_fd(p_sess);
if (vsf_sysutil_retval_is_error(remote_fd))
{
goto dir_close_out;
}
vsf_cmdio_write(p_sess, FTP_DATACONN, "Here comes the directory listing.");
if (p_sess->is_anonymous && p_dir && tunable_anon_world_readable_only)
{
vsf_sysutil_dir_stat(p_dir, &s_p_dirstat);
if (!vsf_sysutil_statbuf_is_readable_other(s_p_dirstat))
{
dir_allow_read = 0;
}
}
if (p_dir == 0 || !dir_allow_read)
{
vsf_cmdio_write(p_sess, FTP_TRANSFEROK,
"Transfer done (but failed to open directory).");
}
else
{
(void) vsf_ftpdataio_transfer_dir(p_sess, remote_fd, p_dir,
&s_dir_name_str, &s_option_str,
&s_filter_str, full_details);
}
(void) dispose_remote_transfer_fd(p_sess);
dir_close_out:
if (p_dir)
{
vsf_sysutil_closedir(p_dir);
}
port_cleanup(p_sess);
pasv_cleanup(p_sess);
}
static void
handle_retr(struct vsf_session* p_sess)
{
static struct mystr s_mark_str;
static struct vsf_sysutil_statbuf* s_p_statbuf;
struct vsf_transfer_ret trans_ret;
int retval;
int remote_fd;
int opened_file;
int is_ascii = 0;
filesize_t offset = p_sess->restart_pos;
p_sess->restart_pos = 0;
if (!pasv_active(p_sess) && !port_active(p_sess))
{
vsf_cmdio_write(p_sess, FTP_BADSENDCONN, "Use PORT or PASV first.");
return;
}
if (p_sess->is_ascii && offset != 0)
{
vsf_cmdio_write(p_sess, FTP_FILEFAIL,
"No support for resume of ASCII transfer.");
return;
}
opened_file = str_open(&p_sess->ftp_arg_str, kVSFSysStrOpenReadOnly);
if (vsf_sysutil_retval_is_error(opened_file))
{
vsf_cmdio_write(p_sess, FTP_FILEFAIL, "Failed to open file.");
return;
}
vsf_sysutil_fstat(opened_file, &s_p_statbuf);
/* No games please */
if (!vsf_sysutil_statbuf_is_regfile(s_p_statbuf))
{
/* Note - pretend open failed */
vsf_cmdio_write(p_sess, FTP_FILEFAIL, "Failed to open file.");
goto file_close_out;
}
/* Optionally, we'll be paranoid and only serve publicly readable stuff */
if (p_sess->is_anonymous && tunable_anon_world_readable_only &&
!vsf_sysutil_statbuf_is_readable_other(s_p_statbuf))
{
vsf_cmdio_write(p_sess, FTP_FILEFAIL, "Failed to open file.");
goto file_close_out;
}
/* Set the download offset (from REST) if any */
if (offset != 0)
{
vsf_sysutil_lseek_to(opened_file, offset);
}
remote_fd = get_remote_transfer_fd(p_sess);
if (vsf_sysutil_retval_is_error(remote_fd))
{
goto port_pasv_cleanup_out;
}
vsf_log_start_entry(p_sess, kVSFLogEntryDownload);
str_copy(&p_sess->log_str, &p_sess->ftp_arg_str);
prepend_path_to_filename(&p_sess->log_str);
str_alloc_text(&s_mark_str, "Opening ");
if (tunable_ascii_download_enable && p_sess->is_ascii)
{
str_append_text(&s_mark_str, "ASCII");
is_ascii = 1;
}
else
{
str_append_text(&s_mark_str, "BINARY");
}
str_append_text(&s_mark_str, " mode data connection for ");
str_append_str(&s_mark_str, &p_sess->ftp_arg_str);
str_append_text(&s_mark_str, " (");
str_append_filesize_t(&s_mark_str,
vsf_sysutil_statbuf_get_size(s_p_statbuf));
str_append_text(&s_mark_str, " bytes).");
vsf_cmdio_write_str(p_sess, FTP_DATACONN, &s_mark_str);
trans_ret = vsf_ftpdataio_transfer_file(p_sess, remote_fd,
opened_file, 0, is_ascii);
p_sess->transfer_size = trans_ret.transferred;
retval = dispose_remote_transfer_fd(p_sess);
/* Log _after_ the blocking dispose call, so we get transfer times right */
if (trans_ret.retval == 0 && retval == 0)
{
vsf_log_do_log(p_sess, 1);
}
else
{
vsf_log_do_log(p_sess, 0);
}
port_pasv_cleanup_out:
port_cleanup(p_sess);
pasv_cleanup(p_sess);
file_close_out:
vsf_sysutil_close(opened_file);
}