From 169677deeb14edbc2eecdd056924af85c6d512d8 Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Wed, 2 Oct 2024 19:02:53 +0200
Subject: [PATCH] Birdloop pipe is set O_CLOEXEC.

If we decide to exec something, we shouldn't pass along our intenal fds.
---
 configure.ac          |  2 ++
 sysdep/unix/io-loop.c | 13 +++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index cf7e60cb..cf0a294e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -281,6 +281,8 @@ sysdep_dirs="`sed <$sysdesc '/^Link: /!d;s/^Link: \(.*\)$/\1/' | tr '\012' ' '`"
 AC_MSG_RESULT([$sysdep_dirs])
 AC_SUBST([sysdep_dirs])
 
+AC_CHECK_FUNCS([pipe2])
+
 if test "$with_iproutedir" = no ; then with_iproutedir= ; fi
 
 if test -n "$given_iproutedir"
diff --git a/sysdep/unix/io-loop.c b/sysdep/unix/io-loop.c
index b4ac55c0..77caf668 100644
--- a/sysdep/unix/io-loop.c
+++ b/sysdep/unix/io-loop.c
@@ -4,6 +4,8 @@
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
 
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -195,15 +197,22 @@ birdloop_in_this_thread(struct birdloop *loop)
 void
 pipe_new(struct pipe *p)
 {
+  int flags = O_NONBLOCK | O_CLOEXEC;
+#if HAVE_PIPE2
+  int rv = pipe2(p->fd, flags);
+  if (rv < 0)
+    die("pipe2: %m");
+#else
   int rv = pipe(p->fd);
   if (rv < 0)
     die("pipe: %m");
 
-  if (fcntl(p->fd[0], F_SETFL, O_NONBLOCK) < 0)
+  if (fcntl(p->fd[0], F_SETFL, flags) < 0)
     die("fcntl(O_NONBLOCK): %m");
 
-  if (fcntl(p->fd[1], F_SETFL, O_NONBLOCK) < 0)
+  if (fcntl(p->fd[1], F_SETFL, flags) < 0)
     die("fcntl(O_NONBLOCK): %m");
+#endif
 }
 
 void