io/fdpass: don't leak fd if conn closes before we write it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/ccan/io/fdpass/fdpass.c b/ccan/io/fdpass/fdpass.c
index e002ddc1f6aadcd3e314d38b135f611dc6137257..d4936ed1ebba576b6b72080b064abd72d8942e03 100644 (file)
--- a/ccan/io/fdpass/fdpass.c
+++ b/ccan/io/fdpass/fdpass.c
@@ -4,6 +4,12 @@
 #include <ccan/io/io_plan.h>
 #include <errno.h>
 
+static void destroy_conn_close_send_fd(struct io_conn *conn,
+                                      struct io_plan_arg *arg)
+{
+       close(arg->u1.s);
+}
+
 static int do_fd_send(int fd, struct io_plan_arg *arg)
 {
        if (!fdpass_send(fd, arg->u1.s)) {
@@ -12,8 +18,11 @@ static int do_fd_send(int fd, struct io_plan_arg *arg)
                        return 0;
                return -1;
        }
-       if (arg->u2.s)
+       if (arg->u2.vp) {
+               struct io_conn *conn = arg->u2.vp;
                close(arg->u1.s);
+               tal_del_destructor2(conn, destroy_conn_close_send_fd, arg);
+       }
        return 1;
 }
 
@@ -26,7 +35,11 @@ struct io_plan *io_send_fd_(struct io_conn *conn,
        struct io_plan_arg *arg = io_plan_arg(conn, IO_OUT);
 
        arg->u1.s = fd;
-       arg->u2.s = fdclose;
+       /* We need conn ptr for destructor */
+       arg->u2.vp = fdclose ? conn : NULL;
+       /* If conn closes before sending, we still need to close fd */
+       if (fdclose)
+               tal_add_destructor2(conn, destroy_conn_close_send_fd, arg);
 
        return io_set_plan(conn, IO_OUT, do_fd_send, next, next_arg);
 }