Resolver fix

[Mark Kettenis]

Here's the patch I promised.  The cast from (struct __sockaddr_in *)
to (struct sockaddr_in *) in res_nsend should be kosher.  Only the
members that are present in both structures are referenced in sock_eq.

The size of `_res' is now back to 512 bytes on the x86.  The other
32-bit systems are probably also OK.  I'm not so sure about the 64-bit
systems though.  I think everything should fit exactly into the 72
bytes padding at the end of the glibc 2.1 `struct __res_state'.  We
might need to adjust the size of the padding in the glibc 2.2 _res._u
union though.  Could the alpha and sparc64 maintainers check please.

Mark


2000-07-20  Mark Kettenis  <kettenis@gnu.org>

	Fix problems with `struct __res_state' getting too big.
	* resolv/resolv.h (struct __sockaddr_in): New definition.
	(struct __res_state): Use __sockaddr_in instead of sockaddr_in in
	the private parts of the structure to save some space.
	* resolv/res_send.c (res_nsend): Cast &EXT(statp).nsaddrs[ns] to
	(struct sockaddr_in *) in call to sock_eq.
	Use memcpy to copy statp->nsaddr_list[ns] to &EXT(statp).nsaddrs[ns].


Index: resolv/resolv.h
===================================================================
RCS file: /cvs/glibc/libc/resolv/resolv.h,v
retrieving revision 1.26
diff -u -p -r1.26 resolv.h
--- resolv/resolv.h	2000/07/19 22:02:37	1.26
+++ resolv/resolv.h	2000/07/20 18:52:25
@@ -123,6 +123,16 @@ struct res_sym {
 #define	RES_DFLRETRY		2	/* Default #/tries. */
 #define	RES_MAXTIME		65535	/* Infinity, in milliseconds. */
 
+/*
+ * Like "struct sockaddr_in", but without any padding (to avoid making
+ * "struct __rest_state" too large).
+ */
+struct __sockaddr_in {
+	__SOCKADDR_COMMON (sin_);
+	in_port_t	sin_port;
+	struct in_addr	sin_addr;
+};
+
 struct __res_state {
 	int	retrans;	 	/* retransmition time interval */
 	int	retry;			/* number of times to retransmit */
@@ -153,7 +163,7 @@ struct __res_state {
 			u_int16_t		nscount;
 			u_int16_t		nstimes[MAXNS];	/* ms. */
 			int			nssocks[MAXNS];
-			struct sockaddr_in	nsaddrs[MAXNS];
+			struct __sockaddr_in	nsaddrs[MAXNS];
 		} _ext;
 	} _u;
 };
Index: resolv/res_send.c
===================================================================
RCS file: /cvs/glibc/libc/resolv/res_send.c,v
retrieving revision 1.26
diff -u -p -r1.26 res_send.c
--- resolv/res_send.c	2000/07/19 22:02:19	1.26
+++ resolv/res_send.c	2000/07/20 18:52:25
@@ -361,6 +361,9 @@ res_nsend(res_state statp,
 		else
 			for (ns = 0; ns < statp->nscount; ns++)
 				if (!sock_eq(&statp->nsaddr_list[ns],
+#ifdef _LIBC
+					     (struct sockaddr_in *)
+#endif
 					     &EXT(statp).nsaddrs[ns])) {
 					needclose++;
 					break;
@@ -374,7 +377,13 @@ res_nsend(res_state statp,
 	 */
 	if (EXT(statp).nscount == 0) {
 		for (ns = 0; ns < statp->nscount; ns++) {
+#ifdef _LIBC
+			memcpy(&EXT(statp).nsaddrs[ns],
+			       &statp->nsaddr_list[ns],
+			       sizeof (&EXT(statp).nsaddrs[0]));
+#else
 			EXT(statp).nsaddrs[ns] = statp->nsaddr_list[ns];
+#endif
 			EXT(statp).nstimes[ns] = RES_MAXTIME;
 			EXT(statp).nssocks[ns] = -1;
 		}