actually limit snarf to SNARFSIZE rather than confusing
the sam protocol.

Reference: /n/sources/patch/applied/sam-snarf-sz
Date: Fri Feb 10 19:01:32 CET 2012
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/samterm/mesg.c	Fri Feb 10 19:01:15 2012
+++ /sys/src/cmd/samterm/mesg.c	Fri Feb 10 19:01:14 2012
@@ -33,9 +33,9 @@
 rcv(void)
 {
 	int c;
-	static state = 0;
-	static count = 0;
-	static i = 0;
+	static int state = 0;
+	static int count = 0;
+	static int i = 0;
 	static int errs = 0;
 
 	while((c=rcvchar()) != -1)
@@ -645,10 +645,17 @@
 	if(n >= 0){
 		if(!s1)
 			n = 0;
-		s1 = realloc(s1, n+1);
-		if (!s1)
-			panic("realloc");
-		s1[n] = 0;
+		if(n > SNARFSIZE){
+			s1 = strdup("<snarf too long>");
+			if (!s1)
+				panic("strdup");
+			n = strlen(s1);
+		}else{
+			s1 = realloc(s1, n+1);
+			if (!s1)
+				panic("realloc");
+			s1[n] = 0;
+		}
 		snarflen = n;
 		outTs(Tsetsnarf, n);
 		if(n>0 && write(1, s1, n)!=n)