another crash due to assuming that the page size is relatively small.
also, do raw processing after binary processing.

Reference: /n/patches.lsub.org/patch/telseg
Date: Wed Jul 11 22:10:59 CES 2012
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/ip/telnet.c	Thu Apr 12 12:25:52 2012
+++ /sys/src/cmd/ip/telnet.c	Wed Jul 11 20:59:21 2012
@@ -33,7 +33,7 @@
 int	echochange(Biobuf*, int);
 int	termsub(Biobuf*, uchar*, int);
 int	xlocsub(Biobuf*, uchar*, int);
-void*	share(ulong);
+void*	share(usize);
 
 static int islikeatty(int);
 
@@ -564,7 +564,7 @@
  *  create a shared segment.
  */
 void*
-share(ulong len)
+share(usize len)
 {
 	uchar *vastart;
 
--- /sys/src/cmd/ip/telnetd.c	Thu Apr 12 12:25:52 2012
+++ /sys/src/cmd/ip/telnetd.c	Wed Jul 11 20:56:05 2012
@@ -43,7 +43,7 @@
 int	xlocsub(Biobuf*, uchar*, int);
 int	challuser(char*);
 int	noworldlogin(char*);
-void*	share(ulong);
+void*	share(usize);
 int	doauth(char*);
 
 #define TELNETLOG "telnet"
@@ -128,6 +128,7 @@
 	/* setup default telnet options */
 	if(!noproto){
 		send3(1, Iac, Will, opt[Echo].code);
+		send3(1, Iac, Do, opt[Line].code);
 		send3(1, Iac, Do, opt[Term].code);
 		send3(1, Iac, Do, opt[Xloc].code);
 	}
@@ -398,12 +399,6 @@
 		} else
 			crnl = 0;
 
-		/* raw processing (each character terminates */
-		if(cons->raw){
-			*bp++ = c;
-			break;
-		}
-
 		/* in binary mode, there are no control characters */
 		if(opt[Binary].local){
 			if(opt[Echo].local)
@@ -411,6 +406,15 @@
 			*bp++ = c;
 			continue;
 		}
+ 
+		/* raw processing (each character terminates) */
+		if(cons->raw){
+			if(c == 0x00)
+			if(!noproto)		/* telnet ignores nulls */
+				continue;
+			*bp++ = c;
+			break;
+		}
 
 		/* cooked processing */
 		switch(c){
@@ -541,21 +545,16 @@
 }
 
 /*
- *  create a shared segment.  Make is start 2 meg higher than the current
- *  end of process memory.
+ *  create a shared segment.
  */
 void*
-share(ulong len)
+share(usize len)
 {
 	uchar *vastart;
 
-	vastart = sbrk(0);
-	if(vastart == (void*)-1)
-		return 0;
-	vastart += 2*1024*1024;
-
-	if(segattach(0, "shared", vastart, len) == (void*)-1)
-		return 0;
+	vastart = segattach(0, "shared", 0, len);
+	if(vastart== (void*)-1)
+		sysfatal("segattach: %r");
 
 	return vastart;
 }