Fix use of free in walsender error handling after a sysid mismatch.

hlinnaka · hlinnaka · commit e0070a6858cf · 2014-05-06T15:17:07.000+03:00
Found via valgrind. The bug exists since the introduction of the walsender,
so backpatch to 9.0.

Andres Freund
diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -135,6 +135,7 @@ libpqrcv_connect(char *conninfo, XLogRecPtr startpoint)
 			 GetSystemIdentifier());
 	if (strcmp(primary_sysid, standby_sysid) != 0)
 	{
+		primary_sysid = pstrdup(primary_sysid);
 		PQclear(res);
 		ereport(ERROR,
 				(errmsg("database system identifier differs between the primary and standby"),

Original file line number	Diff line number	Diff line change
`@@ -135,6 +135,7 @@ libpqrcv_connect(char *conninfo, XLogRecPtr startpoint)`
`135`	`135`	`GetSystemIdentifier());`
`136`	`136`	`if (strcmp(primary_sysid, standby_sysid) != 0)`
`137`	`137`	`{`
	`138`	`+ primary_sysid = pstrdup(primary_sysid);`
`138`	`139`	`PQclear(res);`
`139`	`140`	`ereport(ERROR,`
`140`	`141`	`(errmsg("database system identifier differs between the primary and standby"),`