Tweak TCP-keepalive code so that an invalid setting doesn't cause us

to drop connections unceremoniously.  Also some other marginal cleanups:
don't query getsockopt() repeatedly if it fails, and avoid having the
apparent definition of struct Port depend on which system headers you
might have included or not.  Oliver Jowett and Tom Lane.

1 files changed, 60 insertions, 37 deletions

diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 6c2f6fd14e8..23a9865acb5 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -30,7 +30,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.178 2005/07/30 20:28:20 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.179 2005/09/12 02:26:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -595,18 +595,16 @@ StreamConnection(int server_fd, Port *port)
 			return STATUS_ERROR;
 		}
 
-		/* Set default keepalive parameters. This should also catch
-		 * misconfigurations (non-zero values when socket options aren't
-		 * supported)
+		/*
+		 * Also apply the current keepalive parameters.  If we fail to set
+		 * a parameter, don't error out, because these aren't universally
+		 * supported.  (Note: you might think we need to reset the GUC
+		 * variables to 0 in such a case, but it's not necessary because
+		 * the show hooks for these variables report the truth anyway.)
 		 */
-		if (pq_setkeepalivesidle(tcp_keepalives_idle, port) != STATUS_OK)
-			return STATUS_ERROR;
-
-		if (pq_setkeepalivesinterval(tcp_keepalives_interval, port) != STATUS_OK)
-			return STATUS_ERROR;
-
-		if (pq_setkeepalivescount(tcp_keepalives_count, port) != STATUS_OK)
-			return STATUS_ERROR;
+		(void) pq_setkeepalivesidle(tcp_keepalives_idle, port);
+		(void) pq_setkeepalivesinterval(tcp_keepalives_interval, port);
+		(void) pq_setkeepalivescount(tcp_keepalives_count, port);
 	}
 
 	return STATUS_OK;
@@ -1172,11 +1170,16 @@ pq_endcopyout(bool errorAbort)
 	DoingCopyOut = false;
 }
 
+
+/*
+ * Support for TCP Keepalive parameters
+ */
+
 int
 pq_getkeepalivesidle(Port *port)
 {
 #ifdef TCP_KEEPIDLE
-	if (IS_AF_UNIX(port->laddr.addr.ss_family))
+	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return 0;
 
 	if (port->keepalives_idle != 0)
@@ -1185,12 +1188,13 @@ pq_getkeepalivesidle(Port *port)
 	if (port->default_keepalives_idle == 0)
 	{
 		socklen_t size = sizeof(port->default_keepalives_idle);
+
 		if (getsockopt(port->sock, IPPROTO_TCP, TCP_KEEPIDLE,
-					   (char *) &port->default_keepalives_idle, 
+					   (char *) &port->default_keepalives_idle,
 					   &size) < 0)
 		{
 			elog(LOG, "getsockopt(TCP_KEEPIDLE) failed: %m");
-			return -1;
+			port->default_keepalives_idle = -1;	/* don't know */
 		}
 	}
 
@@ -1199,23 +1203,28 @@ pq_getkeepalivesidle(Port *port)
 	return 0;
 #endif
 }
-   
+
 int
 pq_setkeepalivesidle(int idle, Port *port)
 {
-	if (IS_AF_UNIX(port->laddr.addr.ss_family))
+	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return STATUS_OK;
 
 #ifdef TCP_KEEPIDLE
 	if (idle == port->keepalives_idle)
 		return STATUS_OK;
 
-	if (port->default_keepalives_idle == 0)
+	if (port->default_keepalives_idle <= 0)
 	{
 		if (pq_getkeepalivesidle(port) < 0)
-			return STATUS_ERROR;
+		{
+			if (idle == 0)
+				return STATUS_OK; /* default is set but unknown */
+			else
+				return STATUS_ERROR;
+		}
 	}
-			
+
 	if (idle == 0)
 		idle = port->default_keepalives_idle;
 
@@ -1242,7 +1251,7 @@ int
 pq_getkeepalivesinterval(Port *port)
 {
 #ifdef TCP_KEEPINTVL
-	if (IS_AF_UNIX(port->laddr.addr.ss_family))
+	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return 0;
 
 	if (port->keepalives_interval != 0)
@@ -1251,12 +1260,13 @@ pq_getkeepalivesinterval(Port *port)
 	if (port->default_keepalives_interval == 0)
 	{
 		socklen_t size = sizeof(port->default_keepalives_interval);
+
 		if (getsockopt(port->sock, IPPROTO_TCP, TCP_KEEPINTVL,
-					   (char *) &port->default_keepalives_interval, 
+					   (char *) &port->default_keepalives_interval,
 					   &size) < 0)
 		{
 			elog(LOG, "getsockopt(TCP_KEEPINTVL) failed: %m");
-			return -1;
+			port->default_keepalives_interval = -1;	/* don't know */
 		}
 	}
 
@@ -1265,22 +1275,28 @@ pq_getkeepalivesinterval(Port *port)
 	return 0;
 #endif
 }
-   
+
 int
 pq_setkeepalivesinterval(int interval, Port *port)
 {
-	if (IS_AF_UNIX(port->laddr.addr.ss_family))
+	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return STATUS_OK;
 
 #ifdef TCP_KEEPINTVL
 	if (interval == port->keepalives_interval)
 		return STATUS_OK;
 
-	if (port->default_keepalives_interval == 0) {
+	if (port->default_keepalives_interval <= 0)
+	{
 		if (pq_getkeepalivesinterval(port) < 0)
-			return STATUS_ERROR;
+		{
+			if (interval == 0)
+				return STATUS_OK; /* default is set but unknown */
+			else
+				return STATUS_ERROR;
+		}
 	}
-			
+
 	if (interval == 0)
 		interval = port->default_keepalives_interval;
 
@@ -1297,7 +1313,7 @@ pq_setkeepalivesinterval(int interval, Port *port)
 	{
 		elog(LOG, "setsockopt(TCP_KEEPINTVL) not supported");
 		return STATUS_ERROR;
-	}		
+	}
 #endif
 
 	return STATUS_OK;
@@ -1307,7 +1323,7 @@ int
 pq_getkeepalivescount(Port *port)
 {
 #ifdef TCP_KEEPCNT
-	if (IS_AF_UNIX(port->laddr.addr.ss_family))
+	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return 0;
 
 	if (port->keepalives_count != 0)
@@ -1316,12 +1332,13 @@ pq_getkeepalivescount(Port *port)
 	if (port->default_keepalives_count == 0)
 	{
 		socklen_t size = sizeof(port->default_keepalives_count);
+
 		if (getsockopt(port->sock, IPPROTO_TCP, TCP_KEEPCNT,
-					   (char *) &port->default_keepalives_count, 
+					   (char *) &port->default_keepalives_count,
 					   &size) < 0)
 		{
 			elog(LOG, "getsockopt(TCP_KEEPCNT) failed: %m");
-			return -1;
+			port->default_keepalives_count = -1;	/* don't know */
 		}
 	}
 
@@ -1330,22 +1347,28 @@ pq_getkeepalivescount(Port *port)
 	return 0;
 #endif
 }
-   
+
 int
 pq_setkeepalivescount(int count, Port *port)
 {
-	if (IS_AF_UNIX(port->laddr.addr.ss_family))
+	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
 		return STATUS_OK;
 
 #ifdef TCP_KEEPCNT
 	if (count == port->keepalives_count)
 		return STATUS_OK;
 
-	if (port->default_keepalives_count == 0) {
+	if (port->default_keepalives_count <= 0)
+	{
 		if (pq_getkeepalivescount(port) < 0)
-			return STATUS_ERROR;
+		{
+			if (count == 0)
+				return STATUS_OK; /* default is set but unknown */
+			else
+				return STATUS_ERROR;
+		}
 	}
-			
+
 	if (count == 0)
 		count = port->default_keepalives_count;