ITS#9112 cleaner error handling during connection setup

And additional debug code for tracking errant close()s

servers/slapd/connection.c

@@ -522,6 +522,23 @@ Connection * connection_init(
 		Debug( LDAP_DEBUG_ANY,
 			"connection_init(%d, %s): set nonblocking failed\n",
 			s, c->c_peer_name.bv_val );
+
+		c->c_listener = NULL;
+		if(c->c_peer_domain.bv_val != NULL) {
+			free(c->c_peer_domain.bv_val);
+		}
+		BER_BVZERO( &c->c_peer_domain );
+		if(c->c_peer_name.bv_val != NULL) {
+			free(c->c_peer_name.bv_val);
+		}
+		BER_BVZERO( &c->c_peer_name );
+
+		ber_sockbuf_free( c->c_sb );
+		c->c_sb = NULL;
+		c->c_sd = AC_SOCKET_INVALID;
+		ldap_pvt_thread_mutex_unlock( &c->c_mutex );
+
+		return NULL;
 	}
 
 	ldap_pvt_thread_mutex_lock( &conn_nextid_mutex );

servers/slapd/daemon.c

@@ -1085,6 +1085,50 @@ slapd_sock2fd( ber_socket_t s )
 }
 #endif
 
+#ifdef DEBUG_CLOSE
+/* Was used to find a bug causing slapd's descriptors to be closed
+ * out from under it. Tracked it down to a long-standing (from 2009)
+ * bug in Heimdal https://github.com/heimdal/heimdal/issues/431 .
+ * Leaving this here for future use, if necessary.
+ */
+#include <dlfcn.h>
+#ifndef RTLD_NEXT
+#define RTLD_NEXT	(void *)-1L
+#endif
+static char *newconns;
+typedef int (closefunc)(int fd);
+static closefunc *close_ptr;
+int close( int s )
+{
+	if (newconns) {
+		Debug( LDAP_DEBUG_CONNS,
+			"daemon: close(%ld)\n", s, 0, 0 );
+		if (s >= 0 && s < dtblsize && newconns[s])
+			assert(newconns[s] == 2);
+	}
+	return close_ptr ? close_ptr(s) : -1;
+}
+
+void slapd_debug_close()
+{
+	if (dtblsize)
+		newconns = ch_calloc(1, dtblsize);
+	close_ptr = dlsym(RTLD_NEXT, "close");
+}
+
+void slapd_set_close(int fd)
+{
+	newconns[fd] = 3;
+}
+#define SETUP_CLOSE()	slapd_debug_close()
+#define SET_CLOSE(fd)	slapd_set_close(fd)
+#define CLR_CLOSE(fd)	if (newconns[fd]) newconns[fd]--
+#else
+#define SETUP_CLOSE(fd)
+#define SET_CLOSE(fd)
+#define CLR_CLOSE(fd)
+#endif
+
 /*
  * Add a descriptor to daemon control
  *
@@ -1148,6 +1192,7 @@ slapd_remove(
 	if ( waswriter ) slap_daemon[id].sd_nwriters--;
 
 	SLAP_SOCK_DEL(id, s);
+	CLR_CLOSE(s);
 
 	if ( sb )
 		ber_sockbuf_free(sb);
@@ -1253,6 +1298,7 @@ slapd_close( ber_socket_t s )
 {
 	Debug( LDAP_DEBUG_CONNS, "daemon: closing %ld\n",
 		(long) s );
+	CLR_CLOSE( SLAP_FD2SOCK(s) );
 	tcp_close( SLAP_FD2SOCK(s) );
 #ifdef HAVE_WINSOCK
 	slapd_sockdel( s );
@@ -1862,6 +1908,8 @@ slapd_daemon_init( const char *urls )
 	dtblsize = FD_SETSIZE;
 #endif /* ! HAVE_SYSCONF && ! HAVE_GETDTABLESIZE */
 
+	SETUP_CLOSE();
+
 	/* open a pipe (or something equivalent connected to itself).
 	 * we write a byte on this fd whenever we catch a signal. The main
 	 * loop will be select'ing on this socket, and will wake up when
@@ -2070,6 +2118,11 @@ slap_listener(
 #  endif /* LDAP_PF_LOCAL */
 
 	s = accept( SLAP_FD2SOCK( sl->sl_sd ), (struct sockaddr *) &from, &len );
+	if ( s != AC_SOCKET_INVALID ) {
+		SET_CLOSE(s);
+	}
+	Debug( LDAP_DEBUG_CONNS,
+		"daemon: accept() = %ld\n", s, 0, 0 );
 
 	/* Resume the listener FD to allow concurrent-processing of
 	 * additional incoming connections.
@@ -2141,6 +2194,8 @@ slap_listener(
 			Debug( LDAP_DEBUG_ANY,
 				"slapd(%ld): setsockopt(SO_KEEPALIVE) failed "
 				"errno=%d (%s)\n", (long) sfd, err, sock_errstr(err) );
+			slapd_close(sfd);
+			return 0;
 		}
 #endif /* SO_KEEPALIVE */
 #ifdef TCP_NODELAY
@@ -2153,6 +2208,8 @@ slap_listener(
 			Debug( LDAP_DEBUG_ANY,
 				"slapd(%ld): setsockopt(TCP_NODELAY) failed "
 				"errno=%d (%s)\n", (long) sfd, err, sock_errstr(err) );
+			slapd_close(sfd);
+			return 0;
 		}
 #endif /* TCP_NODELAY */
 	}
@@ -3322,6 +3379,9 @@ slap_unpause_server( void )
 void
 slapd_add_internal( ber_socket_t s, int isactive )
 {
+	if (!isactive) {
+		SET_CLOSE(s);
+	}
 	slapd_add( s, isactive, NULL, -1 );
 }
 

servers/slapd/main.c

@@ -401,11 +401,16 @@ int main( int argc, char **argv )
 
 	slap_sl_mem_init();
 
+
 	(void) ldap_pvt_thread_initialize();
 
 	serverName = lutil_progname( "slapd", argc, argv );
 
 	if ( strcmp( serverName, "slapd" ) ) {
+#ifdef DEBUG_CLOSE
+		extern void slapd_debug_close();
+		slapd_debug_close();
+#endif
 		for (i=0; tools[i].name; i++) {
 			if ( !strcmp( serverName, tools[i].name ) ) {
 				rc = tools[i].func(argc, argv);
@@ -649,6 +654,10 @@ int main( int argc, char **argv )
 					optarg );
 			}
 
+#ifdef DEBUG_CLOSE
+			extern void slapd_debug_close();
+			slapd_debug_close();
+#endif
 			/* try full option string first */
 			for ( i = 0; tools[i].name; i++ ) {
 				if ( strcmp( optarg, &tools[i].name[4] ) == 0 ) {