Arrange for client authentication to occur before we select a specific

database to connect to. This is necessary for the walsender code to work
properly (it was previously using an untenable assumption that template1 would
always be available to connect to).  This also gets rid of a small security
shortcoming that was introduced in the original patch to eliminate the flat
authentication files: before, you could find out whether or not the requested
database existed even if you couldn't pass the authentication checks.

The changes needed to support this are mainly just to treat pg_authid and
pg_auth_members as nailed relations, so that we can read them without having
to be able to locate real pg_class entries for them.  This mechanism was
already debugged for pg_database, but we hadn't recognized the value of
applying it to those catalogs too.

Since the current code doesn't have support for accessing toast tables before
we've brought up all of the relcache, remove pg_authid's toast table to ensure
that no one can store an out-of-line toasted value of rolpassword.  The case
seems quite unlikely to occur in practice, and was effectively unsupported
anyway in the old "flatfiles" implementation.

Update genbki.pl to actually implement the same rules as bootstrap.c does for
not-nullability of catalog columns.  The previous coding was a bit cheesy but
worked all right for the previous set of bootstrap catalogs.  It does not work
for pg_authid, where rolvaliduntil needs to be nullable.

Initdb forced due to minor catalog changes (mainly the toast table removal).

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.585 2010/02/16 22:34:54 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.586 2010/04/20 23:48:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201002161
+#define CATALOG_VERSION_NO	201004201
 
 #endif

src/include/catalog/pg_auth_members.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_auth_members.h,v 1.8 2010/01/05 01:06:56 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_auth_members.h,v 1.9 2010/04/20 23:48:47 tgl Exp $
  *
  * NOTES
  *	  the genbki.pl script reads this file and generates .bki
@@ -27,8 +27,9 @@
  * ----------------
  */
 #define AuthMemRelationId	1261
+#define AuthMemRelation_Rowtype_Id	2843
 
-CATALOG(pg_auth_members,1261) BKI_SHARED_RELATION BKI_WITHOUT_OIDS
+CATALOG(pg_auth_members,1261) BKI_SHARED_RELATION BKI_WITHOUT_OIDS BKI_ROWTYPE_OID(2843) BKI_SCHEMA_MACRO
 {
 	Oid			roleid;			/* ID of a role */
 	Oid			member;			/* ID of a member of that role */

src/include/catalog/pg_authid.h

@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_authid.h,v 1.12 2010/01/05 01:06:56 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_authid.h,v 1.13 2010/04/20 23:48:47 tgl Exp $
  *
  * NOTES
  *	  the genbki.pl script reads this file and generates .bki
@@ -40,8 +40,9 @@
  * ----------------
  */
 #define AuthIdRelationId	1260
+#define AuthIdRelation_Rowtype_Id	2842
 
-CATALOG(pg_authid,1260) BKI_SHARED_RELATION
+CATALOG(pg_authid,1260) BKI_SHARED_RELATION BKI_ROWTYPE_OID(2842) BKI_SCHEMA_MACRO
 {
 	NameData	rolname;		/* name of role */
 	bool		rolsuper;		/* read this field via superuser() only! */
@@ -71,7 +72,7 @@ typedef FormData_pg_authid *Form_pg_authid;
  *		compiler constants for pg_authid
  * ----------------
  */
-#define Natts_pg_authid					11
+#define Natts_pg_authid					10
 #define Anum_pg_authid_rolname			1
 #define Anum_pg_authid_rolsuper			2
 #define Anum_pg_authid_rolinherit		3

src/include/catalog/toasting.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/toasting.h,v 1.13 2010/01/06 03:04:03 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/toasting.h,v 1.14 2010/04/20 23:48:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -49,9 +49,6 @@ DECLARE_TOAST(pg_statistic, 2840, 2841);
 DECLARE_TOAST(pg_trigger, 2336, 2337);
 
 /* shared catalogs */
-DECLARE_TOAST(pg_authid, 2842, 2843);
-#define PgAuthidToastTable 2842
-#define PgAuthidToastIndex 2843
 DECLARE_TOAST(pg_database, 2844, 2845);
 #define PgDatabaseToastTable 2844
 #define PgDatabaseToastIndex 2845