[9front] [PATCH] awk: don't write an extra NUL past the end of a block

[Kristo <kristo.ilmari@gmail.com>]

When splitting a record into individual fields awk seems to write an
extra NUL at the end, which is not an issue when a record fits in the
default buffer. However, with larger records the buffer is allocated to
length of the string + 1, meaning that the extra NUL goes past the end
of the block and causes a "mem user overflow" panic.

diff 26c21f9b5d06296d13f40b53de14e22007e189c2 uncommitted
--- a/sys/src/cmd/awk/lib.c
+++ b/sys/src/cmd/awk/lib.c
@@ -287,7 +287,6 @@
 			while (*r != ' ' && *r != '\t' && *r != '\n' && *r != '\0');
 			*fr++ = 0;
 		}
-		*fr = 0;
 	} else if ((sep = *inputFS) == 0) {		/* new: FS="" => 1 char/field */
 		for (i = 0; *r != 0; r += w) {
 			char buf[UTFmax + 1];
@@ -320,7 +319,6 @@
 			if (*r++ == 0)
 				break;
 		}
-		*fr = 0;
 	}
 	if (i > nfields)
 		FATAL("record `%.30s...' has too many fields; can't happen", r);