freeaddrinfo2() does need two parameters after all, per comment by

Kurt Roeckx.  Add some documentation to try to prevent others from
repeating my mistake.

src/backend/libpq/ip.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/libpq/ip.c,v 1.8 2003/06/08 17:42:59 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/libpq/ip.c,v 1.9 2003/06/09 17:59:19 tgl Exp $
  *
  * This file and the IPV6 implementation were initially provided by
  * Nigel Kukard <nkukard@lbsd.net>, Linux Based Systems Design
@@ -73,26 +73,34 @@ getaddrinfo2(const char *hostname, const char *servname,
 
 /*
  *	freeaddrinfo2 - free addrinfo structures for IPv4, IPv6, or Unix
+ *
+ * Note: the ai_family field of the original hint structure must be passed
+ * so that we can tell whether the addrinfo struct was built by the system's
+ * getaddrinfo() routine or our own getaddrinfo_unix() routine.  Some versions
+ * of getaddrinfo() might be willing to return AF_UNIX addresses, so it's
+ * not safe to look at ai_family in the addrinfo itself.
  */
 void
-freeaddrinfo2(struct addrinfo *ai)
+freeaddrinfo2(int hint_ai_family, struct addrinfo *ai)
 {
-	if (ai != NULL)
-	{
 #ifdef HAVE_UNIX_SOCKETS
-		if (ai->ai_family == AF_UNIX)
+	if (hint_ai_family == AF_UNIX)
+	{
+		/* struct was built by getaddrinfo_unix (see getaddrinfo2) */
+		while (ai != NULL)
 		{
-			while (ai != NULL)
-			{
-				struct addrinfo *p = ai;
+			struct addrinfo *p = ai;
 
-				ai = ai->ai_next;
-				free(p->ai_addr);
-				free(p);
-			}
+			ai = ai->ai_next;
+			free(p->ai_addr);
+			free(p);
 		}
-		else
+	}
+	else
 #endif   /* HAVE_UNIX_SOCKETS */
+	{
+		/* struct was built by getaddrinfo() */
+		if (ai != NULL)
 			freeaddrinfo(ai);
 	}
 }
@@ -115,6 +123,8 @@ getaddrinfo_unix(const char *path, const struct addrinfo *hintsp,
 	struct addrinfo *aip;
 	struct sockaddr_un *unp;
 
+	*result = NULL;
+
 	MemSet(&hints, 0, sizeof(hints));
 
 	if (hintsp == NULL)
@@ -138,6 +148,13 @@ getaddrinfo_unix(const char *path, const struct addrinfo *hintsp,
 	if (aip == NULL)
 		return EAI_MEMORY;
 
+	unp = calloc(1, sizeof(struct sockaddr_un));
+	if (unp == NULL)
+	{
+		free(aip);
+		return EAI_MEMORY;
+	}
+
 	aip->ai_family = AF_UNIX;
 	aip->ai_socktype = hints.ai_socktype;
 	aip->ai_protocol = hints.ai_protocol;
@@ -145,10 +162,6 @@ getaddrinfo_unix(const char *path, const struct addrinfo *hintsp,
 	aip->ai_canonname = NULL;
 	*result = aip;
 
-	unp = calloc(1, sizeof(struct sockaddr_un));
-	if (aip == NULL)
-		return EAI_MEMORY;
-
 	unp->sun_family = AF_UNIX;
 	aip->ai_addr = (struct sockaddr *) unp;
 	aip->ai_addrlen = sizeof(struct sockaddr_un);

src/backend/libpq/pqcomm.c

@@ -30,7 +30,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/libpq/pqcomm.c,v 1.155 2003/06/08 17:43:00 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/libpq/pqcomm.c,v 1.156 2003/06/09 17:59:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -242,7 +242,7 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 	{
 		elog(LOG, "server socket failure: getaddrinfo2(): %s",
 			 gai_strerror(ret));
-		freeaddrinfo2(addrs);
+		freeaddrinfo2(hint.ai_family, addrs);
 		return STATUS_ERROR;
 	}
 
@@ -250,7 +250,7 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 	{
 		elog(LOG, "server socket failure: socket(): %s",
 			 strerror(errno));
-		freeaddrinfo2(addrs);
+		freeaddrinfo2(hint.ai_family, addrs);
 		return STATUS_ERROR;
 	}
 
@@ -261,7 +261,7 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 		{
 			elog(LOG, "server socket failure: setsockopt(SO_REUSEADDR): %s",
 				 strerror(errno));
-			freeaddrinfo2(addrs);
+			freeaddrinfo2(hint.ai_family, addrs);
 			return STATUS_ERROR;
 		}
 	}
@@ -278,7 +278,7 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 				 sock_path);
 		else
 			elog(LOG, "\tIf not, wait a few seconds and retry.");
-		freeaddrinfo2(addrs);
+		freeaddrinfo2(hint.ai_family, addrs);
 		return STATUS_ERROR;
 	}
 
@@ -287,7 +287,7 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 	{
 		if (Setup_AF_UNIX() != STATUS_OK)
 		{
-			freeaddrinfo2(addrs);
+			freeaddrinfo2(hint.ai_family, addrs);
 			return STATUS_ERROR;
 		}
 	}
@@ -307,14 +307,13 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 	{
 		elog(LOG, "server socket failure: listen(): %s",
 			 strerror(errno));
-		freeaddrinfo2(addrs);
+		freeaddrinfo2(hint.ai_family, addrs);
 		return STATUS_ERROR;
 	}
 
 	*fdP = fd;
-	freeaddrinfo2(addrs);
+	freeaddrinfo2(hint.ai_family, addrs);
 	return STATUS_OK;
-
 }