From 8c5069c6374778bab17cd640b2579c936c635fa7 Mon Sep 17 00:00:00 2001
From: Sebastian Lackner <sebastian@fds-team.de>
Date: Tue, 28 Nov 2017 00:11:15 +0100
Subject: [PATCH] syscallcompat: Fix Fchownat syscall wrapper on darwin

* Acquire the lock before reading the current directory
* Fix a file descriptor leak
---
 internal/syscallcompat/sys_darwin.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/internal/syscallcompat/sys_darwin.go b/internal/syscallcompat/sys_darwin.go
index 5bc5fba..5504860 100644
--- a/internal/syscallcompat/sys_darwin.go
+++ b/internal/syscallcompat/sys_darwin.go
@@ -134,12 +134,13 @@ func Dup3(oldfd int, newfd int, flags int) (err error) {
 
 // Poor man's Fchownat.
 func Fchownat(dirfd int, path string, uid int, gid int, flags int) (err error) {
+	chdirMutex.Lock()
+	defer chdirMutex.Unlock()
 	cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
 	if err != nil {
 		return err
 	}
-	chdirMutex.Lock()
-	defer chdirMutex.Unlock()
+	defer syscall.Close(cwd)
 	err = syscall.Fchdir(dirfd)
 	if err != nil {
 		return err