static void do_retr(session_t *sess)
{
if(get_transfer_fd(sess) == 0)
return;
int fd = open(sess->arg, O_RDONLY);
if(fd == -1)
{
ftp_reply(sess, FTP_FILEFAIL, "1Failed to open file.");
return;
}
int ret;
ret = lock_file_read(fd);
if(ret == -1)
{
ftp_reply(sess, FTP_FILEFAIL, "Failed to open file.");
return;
}
//device file can not be downloaded
struct stat sbuf;
ret = fstat(fd, &sbuf);
if(!S_ISREG(sbuf.st_mode))
{
ftp_reply(sess, FTP_FILEFAIL, "Failed to open file.");
return;
}
long long offset = sess->restart_pos;
sess->restart_pos = 0;
if(offset != 0)
{
ret = lseek(fd, offset, SEEK_SET);
if(ret == -1)
{
ftp_reply(sess, FTP_FILEFAIL, "Failed to open file.");
return;
}
}
char text[1024] = {0};
if(sess->is_ascii)
{
sprintf(text, "Opening ASCII mode data conection for %s (%lld bytes).",
sess->arg, (long long)sbuf.st_size);
}
else
{
sprintf(text, "Opening BINARY mode data conection for %s (%lld bytes).",
sess->arg, (long long)sbuf.st_size);
}
ftp_reply(sess, FTP_DATACONN, text);
int flag = 0;
long long bytes_to_send = sbuf.st_size;
if(offset > bytes_to_send)
bytes_to_send = 0;
else
bytes_to_send -= offset;
sess->bw_transfer_start_sec = get_time_sec();
sess->bw_transfer_start_usec = get_time_usec();
while(bytes_to_send)
{
int num_this_time = bytes_to_send > 65536 ? 65536 : bytes_to_send;
ret = sendfile(sess->data_fd, fd, NULL, num_this_time);
if(ret == -1)
{
flag = 2;
break;
}
limit_rate(sess, ret, 0);
if(sess->abor_received)
{
flag = 2;
break;
}
bytes_to_send -= ret;
}
close(sess->data_fd);
sess->data_fd = -1;
close(fd);
if(flag == 0)
ftp_reply(sess, FTP_TRANSFEROK, "Transfer complete.");
else if(flag == 1)
ftp_reply(sess, FTP_BADSENDFILE, "Failure reading from local file.");
else if(flag == 2)
ftp_reply(sess, FTP_BADSENDNET, "Failure writing to network stream.");
check_abor(sess);
start_cmdio_alarm();
}
void do_cmd_retr(session_t *pses)
{
//创建数据连接
if(get_transfer_fd(pses) < 0)
return;
long long offset = 0;
if(pses->restart_pos > 0) //是否需要断点续传
{
offset = pses->restart_pos;
pses->restart_pos = 0;
}
//打开文件
int fd = open(pses->arg, O_RDONLY);
if(fd < 0)
{
ftp_reply(pses->ctrl_fd, FTP_FILEFAIL, "Failed to open file.");
return;
}
//给文件加读锁
int iret = lock_file_read(fd);
if(iret == -1)
{
ftp_reply(pses->ctrl_fd, FTP_FILEFAIL, "Failed to open file.");
return;
}
//判定文件属性是否是普通文件
struct stat sbuf;
iret = fstat(fd, &sbuf);
if(!S_ISREG(sbuf.st_mode))
{
ftp_reply(pses->ctrl_fd, FTP_FILEFAIL, "Failed to open file.");
return;
}
//定位到断点
if(offset > 0)
{
iret = lseek(fd, offset, SEEK_SET);
if(iret < 0)
{
ftp_reply(pses->ctrl_fd, FTP_FILEFAIL, "Failed to open file.");
return;
}
}
//150 应答
char sendbuf[1024] = {0};
if(pses->is_ascii)
{
sprintf(sendbuf, "Opening ASCII mode data connection for %s (%lld bytes).",
pses->arg, (long long)sbuf.st_size);
}
else
{
sprintf(sendbuf, "Opening BINARY mode data connection for %s (%lld bytes).",
pses->arg, (long long)sbuf.st_size);
}
ftp_reply(pses->ctrl_fd, FTP_DATACONN, sendbuf);
//传输文件
int flag = 0;
long long bytes_to_send = sbuf.st_size;
if(offset > bytes_to_send) //客户端发来的断点位置超过了文件长度
{
bytes_to_send = 0;
}
else
{
bytes_to_send -= offset;
}
//发送数据
while(bytes_to_send > 0)
{
int num_this_time = bytes_to_send > 4096 ? 4096 : bytes_to_send;
iret = sendfile64(pses->data_fd, fd, NULL, num_this_time);
if(iret < 0)
{
flag = -2;
break;
}
bytes_to_send -= iret;
}
//发送成功
if(bytes_to_send == 0)
{
flag = 0;
}
//关闭数据套接字
close(pses->data_fd);
pses->data_fd = -1;
//关闭文件
unlock_file(fd);
close(fd);
if(flag == 0)
{
//226
ftp_reply(pses->ctrl_fd, FTP_TRANSFEROK, "Transfer complete.");
}
else if(flag == -2)
{
//451
ftp_reply(pses->ctrl_fd, FTP_BADSENDNET, "Failure writting to network stream.");
}
}