From 7aebe9181068d7313a4b10f56df00adad2b0e924 Mon Sep 17 00:00:00 2001
From: Cole Helbling <cole.e.helbling@outlook.com>
Date: Fri, 8 Apr 2022 08:25:10 -0700
Subject: [PATCH] Revert "libutil: don't save cwd fd, use path instead"

This reverts commit 56009b2639dc878be11f94d096fae56ac14dcd1d.
---
 src/libutil/util.cc | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 885bae69c9b..dcbe92ebce7 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -1801,11 +1801,13 @@ void restoreMountNamespace()
 {
 #if __linux__
     try {
-        auto savedCwd = absPath(".");
-
+        AutoCloseFD fdSavedCwd = open("/proc/self/cwd", O_RDONLY);
+        if (!fdSavedCwd) {
+            throw SysError("saving cwd");
+        }
         if (fdSavedMountNamespace && setns(fdSavedMountNamespace.get(), CLONE_NEWNS) == -1)
             throw SysError("restoring parent mount namespace");
-        if (chdir(savedCwd.c_str()) == -1) {
+        if (fdSavedCwd && fchdir(fdSavedCwd.get()) == -1) {
             throw SysError("restoring cwd");
         }
     } catch (Error & e) {