From 8cf981ca12a295b605b2578cd4b347a08a80dee6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Sun, 3 Nov 2019 01:14:02 +0100
Subject: [PATCH] slave: turn on FD_CLOEXEC after slave has been spawned

This ensures that our ptmx FD isn't carried over to other terminals
spawned later.
---
 slave.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/slave.c b/slave.c
index 1f70a0d8..cc41f39a 100644
--- a/slave.c
+++ b/slave.c
@@ -127,6 +127,15 @@ slave_spawn(int ptmx, int argc, char *const *argv,
             return -1;
         } else
             LOG_DBG("%s: successfully started", conf_shell);
+
+        int fd_flags;
+        if ((fd_flags = fcntl(ptmx, F_GETFD)) < 0 ||
+            fcntl(ptmx, F_SETFD, fd_flags | FD_CLOEXEC) < 0)
+        {
+            LOG_ERRNO("failed to set FD_CLOEXEC on ptmx");
+            return -1;
+        }
+
         break;
     }
     }