Add some extra checks to make sure that a child ypserv process doesn't

try to fork() a child of its own, which could result in several children
ypservs running at once. I'm still not sure exactly what leads to this
condition, but these fixes should stop it from causing trouble. A new
function, yp_fork() checks to see if the current process is already a
child of the parent ypserv, and returns failure (and logs an error message)
rather than spawning another child.

1 files changed, 13 insertions, 9 deletions

diff --git a/usr.sbin/ypserv/yp_main.c b/usr.sbin/ypserv/yp_main.c
index f20ccb3..dbd38fe 100644
--- a/usr.sbin/ypserv/yp_main.c
+++ b/usr.sbin/ypserv/yp_main.c
@@ -32,7 +32,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-	"$Id: yp_main.c,v 1.18 1998/06/04 15:11:14 wpaul Exp $";
+	"$Id: yp_main.c,v 1.19 1999/02/10 16:16:14 wpaul Exp $";
 #endif /* not lint */
 
 /*
@@ -99,6 +99,8 @@ void _msgout(char* msg)
 		syslog(LOG_ERR, msg);
 }
 
+pid_t	yp_pid;
+
 static void
 yp_svc_run()
 {
@@ -108,12 +110,11 @@ yp_svc_run()
 	int readfds;
 #endif /* def FD_SETSIZE */
 	extern int forked;
-	int pid;
 	int fd_setsize = _rpc_dtablesize();
 	struct timeval timeout;
 
 	/* Establish the identity of the parent ypserv process. */
-	pid = getpid();
+	yp_pid = getpid();
 
 	for (;;) {
 #ifdef FD_SETSIZE
@@ -135,16 +136,19 @@ yp_svc_run()
 			warn("svc_run: - select failed");
 			return;
 		case 0:
-			yp_prune_dnsq();
+			if (getpid() == yp_pid)
+				yp_prune_dnsq();
 			break;
 		default:
-			if (FD_ISSET(resfd, &readfds)) {
-				yp_run_dnsq();
-				FD_CLR(resfd, &readfds);
+			if (getpid() == yp_pid) {
+				if (FD_ISSET(resfd, &readfds)) {
+					yp_run_dnsq();
+					FD_CLR(resfd, &readfds);
+				}
+				svc_getreqset(&readfds);
 			}
-			svc_getreqset(&readfds);
 		}
-		if (forked && pid != getpid())
+		if (yp_pid != getpid())
 			_exit(0);
 	}
 }