1 files changed, 12 insertions, 3 deletions
diff --git a/src/ninep/tree.zig b/src/ninep/tree.zig
index d39854e1..61ac7e87 100644
--- a/src/ninep/tree.zig
+++ b/src/ninep/tree.zig
@@ -1147,12 +1147,21 @@ fn holdsLines(p: *Pardes, req: Req) bool {
 /// A line held back longer than this is refused rather than kept growing.
 const pending_cap = 1 << 20;
 
+/// The ctl files, whose lines are commands as look's and exec's are.
+fn ctlFile(target: Target) bool {
+    return switch (target) {
+        .top => |f| f == .ctl,
+        .col => |c| c.file == .ctl,
+        .pane => |t| t.file == .ctl,
+    };
+}
+
 fn write(p: *Pardes, req: Req, target: Target) Reply {
+    // A command line holds no control character but a tab: the whole write
+    // is refused at once, not held to fail unseen at the close.
+    if (resultsFile(target) or ctlFile(target)) for (req.data) |c| if ((c < ' ' and c != '\t' and c != '\n' and c != '\r') or c == 0x7f) return failText(req.tag, E.INVAL, ctl.e_control);
     const o = (if (linesFile(target)) openOf(p, req) else null) orelse return writeNow(p, req, target);
     if (o.what != .lines and o.what != .ctl) return writeNow(p, req, target);
-    // A clicked line holds no control character: refused at once, not held
-    // to fail unseen at the close.
-    if (resultsFile(target)) for (req.data) |c| if ((c < ' ' and c != '\t' and c != '\n' and c != '\r') or c == 0x7f) return failText(req.tag, E.INVAL, ctl.e_control);
     o.pending.appendSlice(p.gpa, req.data) catch return Reply.fail(req.tag, E.NOMEM);
     var end = ctl.completeEnd(p, o.pending.items);
     // A tail with no newline is a whole line when the write is the whole of