Fix code that doesn't work on machines with strict alignment requirements:

must use memcpy here rather than struct assignment.

In passing, rearrange some randomly-ordered declarations to be a tad less
random.

src/backend/replication/walreceiver.c

@@ -29,7 +29,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/replication/walreceiver.c,v 1.9 2010/04/19 14:10:45 mha Exp $
+ *	  $PostgreSQL: pgsql/src/backend/replication/walreceiver.c,v 1.10 2010/04/20 22:55:03 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -76,9 +76,15 @@ static uint32 recvOff = 0;
 static volatile sig_atomic_t got_SIGHUP = false;
 static volatile sig_atomic_t got_SIGTERM = false;
 
-static void ProcessWalRcvInterrupts(void);
-static void EnableWalRcvImmediateExit(void);
-static void DisableWalRcvImmediateExit(void);
+/*
+ * LogstreamResult indicates the byte positions that we have already
+ * written/fsynced.
+ */
+static struct
+{
+	XLogRecPtr	Write;			/* last byte + 1 written out in the standby */
+	XLogRecPtr	Flush;			/* last byte + 1 flushed in the standby */
+}	LogstreamResult;
 
 /*
  * About SIGTERM handling:
@@ -98,6 +104,21 @@ static void DisableWalRcvImmediateExit(void);
  */
 static volatile bool WalRcvImmediateInterruptOK = false;
 
+/* Prototypes for private functions */
+static void ProcessWalRcvInterrupts(void);
+static void EnableWalRcvImmediateExit(void);
+static void DisableWalRcvImmediateExit(void);
+static void WalRcvDie(int code, Datum arg);
+static void XLogWalRcvProcessMsg(unsigned char type, char *buf, Size len);
+static void XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr);
+static void XLogWalRcvFlush(void);
+
+/* Signal handlers */
+static void WalRcvSigHupHandler(SIGNAL_ARGS);
+static void WalRcvShutdownHandler(SIGNAL_ARGS);
+static void WalRcvQuickDieHandler(SIGNAL_ARGS);
+
+
 static void
 ProcessWalRcvInterrupts(void)
 {
@@ -118,47 +139,25 @@ ProcessWalRcvInterrupts(void)
 }
 
 static void
-EnableWalRcvImmediateExit()
+EnableWalRcvImmediateExit(void)
 {
 	WalRcvImmediateInterruptOK = true;
 	ProcessWalRcvInterrupts();
 }
 
 static void
-DisableWalRcvImmediateExit()
+DisableWalRcvImmediateExit(void)
 {
 	WalRcvImmediateInterruptOK = false;
 	ProcessWalRcvInterrupts();
 }
 
-/* Signal handlers */
-static void WalRcvSigHupHandler(SIGNAL_ARGS);
-static void WalRcvShutdownHandler(SIGNAL_ARGS);
-static void WalRcvQuickDieHandler(SIGNAL_ARGS);
-
-/* Prototypes for private functions */
-static void WalRcvDie(int code, Datum arg);
-static void XLogWalRcvProcessMsg(unsigned char type, char *buf, Size len);
-static void XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr);
-static void XLogWalRcvFlush(void);
-
-/*
- * LogstreamResult indicates the byte positions that we have already
- * written/fsynced.
- */
-static struct
-{
-	XLogRecPtr	Write;			/* last byte + 1 written out in the standby */
-	XLogRecPtr	Flush;			/* last byte + 1 flushed in the standby */
-}	LogstreamResult;
-
 /* Main entry point for walreceiver process */
 void
 WalReceiverMain(void)
 {
 	char		conninfo[MAXCONNINFO];
 	XLogRecPtr	startpoint;
-
 	/* use volatile pointer to prevent code rearrangement */
 	volatile WalRcvData *walrcv = WalRcv;
 
@@ -398,19 +397,21 @@ XLogWalRcvProcessMsg(unsigned char type, char *buf, Size len)
 
 				if (len < sizeof(XLogRecPtr))
 					ereport(ERROR,
-					  (errmsg("invalid WAL message received from primary")));
+							(errcode(ERRCODE_PROTOCOL_VIOLATION),
+							 errmsg_internal("invalid WAL message received from primary")));
 
-				recptr = *((XLogRecPtr *) buf);
+				memcpy(&recptr, buf, sizeof(XLogRecPtr));
 				buf += sizeof(XLogRecPtr);
 				len -= sizeof(XLogRecPtr);
+
 				XLogWalRcvWrite(buf, len, recptr);
 				break;
 			}
 		default:
 			ereport(ERROR,
 					(errcode(ERRCODE_PROTOCOL_VIOLATION),
-					 errmsg("invalid replication message type %d",
-							type)));
+					 errmsg_internal("invalid replication message type %d",
+									 type)));
 	}
 }