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, 8 insertions, 7 deletions

diff --git a/sshd.c b/sshd.c
index ce4a493ef..fafcd3400 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.477 2016/11/29 03:54:50 dtucker Exp $ */
+/* $OpenBSD: sshd.c,v 1.478 2016/11/30 00:28:31 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1343,7 +1343,7 @@ main(int ac, char **av)
         struct ssh *ssh = NULL;
         extern char *optarg;
         extern int optind;
-        int r, opt, i, j, on = 1;
+        int r, opt, i, j, on = 1, already_daemon;
         int sock_in = -1, sock_out = -1, newsock = -1;
         const char *remote_ip;
         int remote_port;
@@ -1802,11 +1802,12 @@ main(int ac, char **av)
         log_init(__progname, options.log_level, options.log_facility, log_stderr);
 
         /*
-         * If not in debugging mode, and not started from inetd, disconnect
-         * from the controlling terminal, and fork.  The original process
-         * exits.
+         * If not in debugging mode, not started from inetd and not already
+         * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
+         * terminal, and fork.  The original process exits.
          */
-        if (!(debug_flag || inetd_flag || no_daemon_flag)) {
+        already_daemon = daemonized();
+        if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
 
                 if (daemon(0, 0) < 0)
                         fatal("daemon() failed: %.200s", strerror(errno));
@@ -1840,7 +1841,7 @@ main(int ac, char **av)
                  * Write out the pid file after the sigterm handler
                  * is setup and the listen sockets are bound
                  */
-                if (options.pid_file != NULL && !debug_flag) {
+                if (options.pid_file != NULL && !debug_flag && !already_daemon) {
                         FILE *f = fopen(options.pid_file, "w");
 
                         if (f == NULL) {