Author: Matthew Ogilvie <mmogilvi+gnto@zoho.com>
Date:   Sun Jul 26 14:38:09 2020 -0600

    ignore exception from os.setsid()
    
    Typically something external (such as start-stop-daemon) will have
    already done a setsid().

diff --git a/replicator/Utils.py b/replicator/Utils.py
index d2c4f94..5b08bcf 100644
--- a/replicator/Utils.py
+++ b/replicator/Utils.py
@@ -12,7 +12,11 @@ def daemonize():
         # attempt most os activity early, to catch errors before we fork
         os.umask(0o022)  # -rw-r--r-- / 0644 / u=rw,go=r
         pidout = OPTS.pidfile and open(OPTS.pidfile, 'w')
-        os.setsid()
+        try:
+            os.setsid()
+        except OSError as e:
+            # ignore EPERM: already a process group leader
+            pass
         #first fork: create intermediate child process
         pid = os.fork()
     except IOError as e: