From 6a45c49c259544ce34c745d23b01886b559b7e4f Mon Sep 17 00:00:00 2001
From: Joe Richey <joerichey@google.com>
Date: Tue, 30 Jul 2019 19:50:06 -0700
Subject: [PATCH] Add RHEL 5 compat

---
 src/util_libc.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/util_libc.rs b/src/util_libc.rs
index 9bcd02b2..dea5a436 100644
--- a/src/util_libc.rs
+++ b/src/util_libc.rs
@@ -128,10 +128,13 @@ cfg_if! {
 // SAFETY: path must be null terminated, FD must be manually closed.
 pub unsafe fn open_readonly(path: &str) -> Option<libc::c_int> {
     debug_assert!(path.as_bytes().last() == Some(&0));
-    // We don't care about Linux OSes too old to support O_CLOEXEC.
     let fd = open(path.as_ptr() as *mut _, libc::O_RDONLY | libc::O_CLOEXEC);
     if fd < 0 {
         return None;
     }
+    // O_CLOEXEC works on all Unix targets except for older Linux kernels (pre
+    // 2.6.23), so we also use an ioctl to make sure FD_CLOEXEC is set.
+    #[cfg(target_os = "linux")]
+    libc::ioctl(self.fd, libc::FIOCLEX);
     Some(fd)
 }