back = NULL; backhandle = NULL;
void do_sftp_cleanup(){    char ch;    if (back) {	back->special(backhandle, TS_EOF);	sftp_recvdata(&ch, 1);	back->free(backhandle);	sftp_cleanup_request();    }    if (pwd) {	sfree(pwd);	pwd = NULL;    }    if (homedir) {	sfree(homedir);	homedir = NULL;    }}