rpcbind/socket-activation-don-t-unlink-socket-we-didn-t-create

From: Jeff Mahoney <jeffm@suse.com>
Subject: socket-activation: don't unlink socket we didn't create
References: bnc#757667

 On an unpatched system, try this:
 rpcinfo <works>
 rcrpcbind restart
 rpcinfo <fails>

 This is due to rpcbind unlinking the socket file when it exits. It
 doesn't own the socket file when socket activation is used - systemd
 does. Systemd still has an open reference to it and when rpcbind is
 restarted, it passes the open reference back to it and rpcbind is
 perfectly happy to accept it. Unfortunately, everything that needs to
 talk to rpcbind no longer can because the socket file each of those
 users needs to open is no longer on the file system.

 This patch adds a new global that's used to avoid unlinking the
 rpcbind.sock socket file during shutdown.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---

 src/rpcbind.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/src/rpcbind.c
+++ b/src/rpcbind.c
@@ -80,6 +81,7 @@
 int debugging = 0;	/* Tell me what's going on */
 int doabort = 0;	/* When debugging, do an abort on errors */
 int dofork = 1;		/* fork? */
+int sock_needs_unlink = 1;	/* we created rpcbind.sock */
 
 rpcblist_ptr list_rbl;	/* A list of version 3/4 rpcbind services */
 
@@ -365,6 +396,14 @@ init_transport(struct netconfig *nconf)
                                nconf->nc_netid);
 			goto error;
 		}
+
+		/*
+		 * We were passed the open UNIX socket
+		 * and shouldn't remove it.
+		 */
+		if (sa.sa.sa_family == AF_UNIX &&
+		    strcmp(sa.un.sun_path, _PATH_RPCBINDSOCK))
+			sock_needs_unlink = 0;
 	}
 
 	/* if none of the systemd sockets matched, we set up the socket in
@@ -784,7 +823,8 @@ static void
 terminate(int dummy /*__unused*/)
 {
 	close(rpcbindlockfd);
-	unlink(_PATH_RPCBINDSOCK);
+	if (sock_needs_unlink)
+		unlink(_PATH_RPCBINDSOCK);
 	unlink(RPCBINDDLOCK);
 #ifdef WARMSTART
 	syslog(LOG_ERR,