totemknet: Remove MSGHDR conditionals

The ucast_sendmsg and mcast_sendmsg functions already initialize
msghdr using memset, making the conditional zeroing of some fields
redundant.

This commit adds a similar memset to data_deliver_fn and
totemknet_recv_mcast_empty to ensure msghdr is always fully
initialized. All conditional initializations are then removed.

This simplifies the code and improves safety by preventing the
use of uninitialized stack data within the msghdr struct.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>

exec/totemknet.c

@@ -416,21 +416,6 @@ static inline void ucast_sendmsg (
 	memset(&msg_ucast, 0, sizeof(msg_ucast));
 	msg_ucast.msg_iov = (void *)&iovec;
 	msg_ucast.msg_iovlen = 1;
-#ifdef HAVE_MSGHDR_CONTROL
-	msg_ucast.msg_control = 0;
-#endif
-#ifdef HAVE_MSGHDR_CONTROLLEN
-	msg_ucast.msg_controllen = 0;
-#endif
-#ifdef HAVE_MSGHDR_FLAGS
-	msg_ucast.msg_flags = 0;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTS
-	msg_ucast.msg_accrights = NULL;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTSLEN
-	msg_ucast.msg_accrightslen = 0;
-#endif
 
 	/*
 	 * Transmit unicast message
@@ -466,22 +451,6 @@ static inline void mcast_sendmsg (
 	memset(&msg_mcast, 0, sizeof(msg_mcast));
 	msg_mcast.msg_iov = (void *)&iovec;
 	msg_mcast.msg_iovlen = 1;
-#ifdef HAVE_MSGHDR_CONTROL
-	msg_mcast.msg_control = 0;
-#endif
-#ifdef HAVE_MSGHDR_CONTROLLEN
-	msg_mcast.msg_controllen = 0;
-#endif
-#ifdef HAVE_MSGHDR_FLAGS
-	msg_mcast.msg_flags = 0;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTS
-	msg_mcast.msg_accrights = NULL;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTSLEN
-	msg_mcast.msg_accrightslen = 0;
-#endif
-
 
 //	log_printf (LOGSYS_LEVEL_DEBUG, "totemknet: mcast_sendmsg. only_active=%d, len=%d", only_active, msg_len);
 
@@ -823,25 +792,11 @@ static int data_deliver_fn (
 	iov_recv.iov_base = instance->iov_buffer;
 	iov_recv.iov_len = KNET_MAX_PACKET_SIZE + 1;
 
+	memset(&msg_hdr, 0, sizeof(msg_hdr));
 	msg_hdr.msg_name = &system_from;
 	msg_hdr.msg_namelen = sizeof (struct sockaddr_storage);
 	msg_hdr.msg_iov = &iov_recv;
 	msg_hdr.msg_iovlen = 1;
-#ifdef HAVE_MSGHDR_CONTROL
-	msg_hdr.msg_control = 0;
-#endif
-#ifdef HAVE_MSGHDR_CONTROLLEN
-	msg_hdr.msg_controllen = 0;
-#endif
-#ifdef HAVE_MSGHDR_FLAGS
-	msg_hdr.msg_flags = 0;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTS
-	msg_hdr.msg_accrights = NULL;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTSLEN
-	msg_hdr.msg_accrightslen = 0;
-#endif
 
 	msg_len = recvmsg (fd, &msg_hdr, MSG_NOSIGNAL | MSG_DONTWAIT);
 	if (msg_len <= 0) {
@@ -1557,25 +1512,11 @@ extern int totemknet_recv_mcast_empty (
 	iov_recv.iov_base = instance->iov_buffer;
 	iov_recv.iov_len = KNET_MAX_PACKET_SIZE;
 
+	memset(&msg_hdr, 0, sizeof(msg_hdr));
 	msg_hdr.msg_name = &system_from;
 	msg_hdr.msg_namelen = sizeof (struct sockaddr_storage);
 	msg_hdr.msg_iov = &iov_recv;
 	msg_hdr.msg_iovlen = 1;
-#ifdef HAVE_MSGHDR_CONTROL
-	msg_hdr.msg_control = 0;
-#endif
-#ifdef HAVE_MSGHDR_CONTROLLEN
-	msg_hdr.msg_controllen = 0;
-#endif
-#ifdef HAVE_MSGHDR_FLAGS
-	msg_hdr.msg_flags = 0;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTS
-	msg_hdr.msg_accrights = NULL;
-#endif
-#ifdef HAVE_MSGHDR_ACCRIGHTSLEN
-	msg_hdr.msg_accrightslen = 0;
-#endif
 
 	do {
 		ufd.fd = instance->knet_fd;