rpcbind: Do not use signal-unsafe functions in SIGTERM handler

syslog(3), routines used in write_warmstart(), and exit(3) are all
signal-unsafe.  Instead, set a signal-safe flag and check the flag in the
rpcbind main loop to shutdown safely.

PR:		224503
Reviewed by:	kib, markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13728

3 files changed, 19 insertions, 10 deletions

diff --git a/usr.sbin/rpcbind/rpcb_svc_com.c b/usr.sbin/rpcbind/rpcb_svc_com.c
index 27230370e9ec..ab454890e0b8 100644
--- a/usr.sbin/rpcbind/rpcb_svc_com.c
+++ b/usr.sbin/rpcbind/rpcb_svc_com.c
@@ -1136,6 +1136,16 @@ my_svc_run(void)
 			 * that it was set by the signal handlers (or any
 			 * other outside event) and not caused by poll().
 			 */
+			if (doterminate != 0) {
+				close(rpcbindlockfd);
+#ifdef WARMSTART
+				syslog(LOG_ERR,
+				    "rpcbind terminating on signal %d. Restart with \"rpcbind -w\"",
+				    (int)doterminate);
+				write_warmstart();	/* Dump yourself */
+#endif
+				exit(2);
+			}
 		case 0:
 			cleanfds = svc_fdset;
 			__svc_clean_idle(&cleanfds, 30, FALSE);
diff --git a/usr.sbin/rpcbind/rpcbind.c b/usr.sbin/rpcbind/rpcbind.c
index 2ae73dd20a4a..71f1e66c925c 100644
--- a/usr.sbin/rpcbind/rpcbind.c
+++ b/usr.sbin/rpcbind/rpcbind.c
@@ -79,7 +79,9 @@ static	char sccsid[] = "@(#)rpcbind.c 1.35 89/04/21 Copyr 1984 Sun Micro";
 /* Global variables */
 int debugging = 0;	/* Tell me what's going on */
 int doabort = 0;	/* When debugging, do an abort on errors */
+volatile sig_atomic_t doterminate = 0;	/* Terminal signal received */
 rpcblist_ptr list_rbl;	/* A list of version 3/4 rpcbind services */
+int rpcbindlockfd;
 
 /* who to suid to if -s is given */
 #define RUN_AS  "daemon"
@@ -99,7 +101,6 @@ static struct sockaddr **bound_sa;
 static int ipv6_only = 0;
 static int nhosts = 0;
 static int on = 1;
-static int rpcbindlockfd;
 
 #ifdef WARMSTART
 /* Local Variable */
@@ -758,16 +759,10 @@ rbllist_add(rpcprog_t prog, rpcvers_t vers, struct netconfig *nconf,
  * Catch the signal and die
  */
 static void
-terminate(int signum __unused)
+terminate(int signum)
 {
-	close(rpcbindlockfd);
-#ifdef WARMSTART
-	syslog(LOG_ERR,
-	    "rpcbind terminating on signal %d. Restart with \"rpcbind -w\"",
-	    signum);
-	write_warmstart();	/* Dump yourself */
-#endif
-	exit(2);
+
+	doterminate = signum;
 }
 
 void
diff --git a/usr.sbin/rpcbind/rpcbind.h b/usr.sbin/rpcbind/rpcbind.h
index f78b2eecc34b..695b24455b16 100644
--- a/usr.sbin/rpcbind/rpcbind.h
+++ b/usr.sbin/rpcbind/rpcbind.h
@@ -44,6 +44,8 @@
 #ifndef rpcbind_h
 #define	rpcbind_h
 
+#include <signal.h>
+
 #ifdef PORTMAP
 #include <rpc/pmap_prot.h>
 #endif
@@ -68,6 +70,7 @@ struct r_rmtcall_args {
 
 extern int debugging;
 extern int doabort;
+extern volatile sig_atomic_t doterminate;
 #ifdef LIBWRAP
 extern int libwrap;
 #endif
@@ -75,6 +78,7 @@ extern int verboselog;
 extern int insecure;
 extern int oldstyle_local;
 extern rpcblist_ptr list_rbl;	/* A list of version 3 & 4 rpcbind services */
+extern int rpcbindlockfd;
 
 #ifdef PORTMAP
 extern struct pmaplist *list_pml; /* A list of version 2 rpcbind services */