code: plan9front

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awk: getline: do not access unitialized data on EOF

echo 'a' | awk 'BEGIN { getline l; getline l; print (s=substr(l,1,10)) " len=" length(s) }'
https://github.com/onetrueawk/awk/commit/1debe1993fc852545a9215621d884be27f08a223

--- a/sys/src/cmd/awk/run.c

+++ b/sys/src/cmd/awk/run.c

@@ -438,10 +438,12 @@

 			n = getrec(&record, &recsize, 1);

 		else {			/* getline var */

 			n = getrec(&buf, &bufsize, 0);

-			x = execute(a[0]);

-			setsval(x, buf);

-			if (istemp(x))

-				tfree(x);

+			if (n > 0) {

+				x = execute(a[0]);

+				setsval(x, buf);

+				if (istemp(x))

+					tfree(x);

+			}

 		}

 	}

 	setfval(r, (Awkfloat) n);