upstream commit

On startup, check to see if sshd is already daemonized
and if so, skip the call to daemon() and do not rewrite the PidFile.  This
means that when sshd re-execs itself on SIGHUP the process ID will no longer
change.  Should address bz#2641.  ok djm@ markus@.

Upstream-ID: 5ea0355580056fb3b25c1fd6364307d9638a37b9

1 files changed, 19 insertions, 1 deletions

diff --git a/misc.c b/misc.c
index 07d4179e4..65c9222aa 100644
--- a/misc.c
+++ b/misc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.c,v 1.106 2016/10/23 22:04:05 dtucker Exp $ */
+/* $OpenBSD: misc.c,v 1.107 2016/11/30 00:28:31 dtucker Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
@@ -1251,3 +1251,21 @@ bind_permitted(int port, uid_t uid)
                 return 0;
         return 1;
 }
+
+/* returns 1 if process is already daemonized, 0 otherwise */
+int
+daemonized(void)
+{
+        int fd;
+
+        if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) {
+                close(fd);
+                return 0;       /* have controlling terminal */
+        }
+        if (getppid() != 1)
+                return 0;       /* parent is not init */
+        if (getsid(0) != getpid())
+                return 0;       /* not session leader */
+        debug3("already daemonized");
+        return 1;
+}