1 files changed, 8 insertions, 0 deletions
diff --git a/src/ninep/pty.zig b/src/ninep/pty.zig
index aa0f499a..bf5f432c 100644
--- a/src/ninep/pty.zig
+++ b/src/ninep/pty.zig
@@ -67,6 +67,14 @@ pub fn writeCtl(p: *Pardes, req: Req, id: usize) Reply {
                 const dir = pane.cwdSlice();
                 return tree.failText(req.tag, E.NOENT, std.fmt.bufPrint(&p.fs.ename, "exec: {s}: no such directory", .{dir[0..@min(dir.len, 256)]}) catch "exec: no such directory");
             };
+            // Nor is a shell that is not there, or a script whose
+            // interpreter is not: refused, and the running shell kept.
+            if (comptime pardes.hosted) if (!apply and std.mem.eql(u8, line, "exec")) if (p.panes[id]) |pane| {
+                const bin = pane.shell orelse p.shellBin();
+                var why: [320]u8 = undefined;
+                if (@import("../host_io.zig").Shell.refusal(bin[0..@min(bin.len, 200)], &why)) |refused|
+                    return tree.failText(req.tag, E.NOENT, std.fmt.bufPrint(&p.fs.ename, "exec: {s}", .{refused}) catch "exec: no such shell");
+            };
             if (!verb(p, id, line, apply)) return tree.failText(req.tag, E.INVAL, if (outOfRange(line)) e_winsize_range else e_bad_pty_ctl);
         }
     }