Package: inetutils-server Version: 1.9.1-2 or older Telnetd in inetutils-server package lacks handling of some of TIOCPKT control bytes. The most influential thing is a lack of handling of TIOCPKT_DATA. TIOCPKT_DATAs i.e. '\0's frequently appear in the stream of network side.
In most cases, '\0' is invisible on a terminal, therefore it is
hardly noticed. However, sometimes multibyte characters are
displayed incorrectly by interference of inserted '\0'.
To reproduce this problem:
1) Install intetutils-server package.
2) Make a typescript file by:
script -qc 'telnet localhost'
3) Do something to produce some text outputs.
4) Logout from the telnet session.
5) Look into the typescript file, then you will find
many extra '\0's (^@) in it.
To fix this problem, I have made following patch.
In this patch, the first byte from read() is always treated as
a TIOCPKT control byte. Therefore, it is simply read out instead
of being peeked. This is based on description in man tty_ioctl,
which says the first byte returned by read() is always a TIOCPKT
control byte.
--- telnetd.c.orig 2012-01-06 22:58:30.000000000 +0900
+++ telnetd.c 2015-02-20 19:18:55.808004100 +0900
@@ -601,11 +601,10 @@ telnetd_run (void)
/* Something to read from the pty... */
if (pty_read () < 0)
break;
- c = pty_get_char (1);
+ c = pty_get_char (0); /* read TIOCPKT control byte */
#if defined TIOCPKT_IOCTL
if (c & TIOCPKT_IOCTL)
{
- pty_get_char (0);
copy_termbuf ();
localstat ();
}
@@ -613,7 +612,6 @@ telnetd_run (void)
if (c & TIOCPKT_FLUSHWRITE)
{
static char flushdata[] = { IAC, DM };
- pty_get_char (0);
netclear (); /* clear buffer back */
net_output_datalen (flushdata, sizeof (flushdata));
set_neturg ();
@@ -630,7 +628,6 @@ telnetd_run (void)
IAC, SB, TELOPT_LFLOW,
flowmode ? LFLOW_ON : LFLOW_OFF, IAC, SE);
}
- pty_get_char (0);
}
}
--
Takashi Yano <takashi.y...@nifty.ne.jp>
cygcheck.out
Description: Binary data
-- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
