From 03331c35a7aa16d2f3b859ba8a9aa4e465bc60c3 Mon Sep 17 00:00:00 2001
From: Jacob Bachmeyer <jcb@gnu.org>
Date: Fri, 14 Oct 2022 22:33:34 -0500
Subject: [PATCH] Add comment describing expected issue on modern GNU/Linux

---
 gatekeeper.pl | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gatekeeper.pl b/gatekeeper.pl
index c952788..4fe6fb7 100755
--- a/gatekeeper.pl
+++ b/gatekeeper.pl
@@ -935,6 +935,9 @@ sub scan_incoming {
   # If neither of those 2 conditions are met, the lsof call will not see
   # the open files because they are owned by another user.
   # On modern (Debian) systems, condition a) is not met.
+  # On modern GNU/Linux systems, unless either condition b) is met or lsof
+  # is installed setuid root, the kernel will not permit the open files to
+  # be seen because they are owned by another user.
   my @lsof_args = (LSOF_BIN, "-Fn",
        map { File::Spec->catfile($directory, $_) } keys %possible);
   ftp_syslog('debug', "DEBUG: lsof command line: " . join(' ',@lsof_args))
-- 
2.25.1