Index: src/backend/catalog/aclchk.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/catalog/aclchk.c,v
retrieving revision 1.114
diff -c -r1.114 aclchk.c
*** src/backend/catalog/aclchk.c	28 Jun 2005 19:51:21 -0000	1.114
--- src/backend/catalog/aclchk.c	3 Jul 2005 05:11:18 -0000
***************
*** 76,88 ****
   * GRANT or REVOKE, we pretend he is the object owner.	This ensures that
   * all granted privileges appear to flow from the object owner, and there
   * are never multiple "original sources" of a privilege.
   */
  static Oid
  select_grantor(Oid ownerId)
  {
  	Oid		grantorId;
  
! 	grantorId = GetUserId();
  
  	/* fast path if no difference */
  	if (grantorId == ownerId)
--- 76,93 ----
   * GRANT or REVOKE, we pretend he is the object owner.	This ensures that
   * all granted privileges appear to flow from the object owner, and there
   * are never multiple "original sources" of a privilege.
+  *
+  * NOTE: SQL spec defines that, unless 'GRANTED BY' is set, the grantor 
+  * is the CURRENT_USER if it is set and the CURRENT_ROLE otherwise.  
+  * CURRENT_USER is always set for us, so we use that.  SQL spec does not 
+  * show a way which CURRENT_USER could become unset.
   */
  static Oid
  select_grantor(Oid ownerId)
  {
  	Oid		grantorId;
  
! 	grantorId = GetCurrentUserId();
  
  	/* fast path if no difference */
  	if (grantorId == ownerId)
Index: src/backend/commands/user.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/commands/user.c,v
retrieving revision 1.155
diff -c -r1.155 user.c
*** src/backend/commands/user.c	29 Jun 2005 20:34:13 -0000	1.155
--- src/backend/commands/user.c	3 Jul 2005 05:11:18 -0000
***************
*** 227,233 ****
  					 errmsg("permission denied to create role")));
  	}
  
! 	if (strcmp(stmt->role, "public") == 0)
  		ereport(ERROR,
  				(errcode(ERRCODE_RESERVED_NAME),
  				 errmsg("role name \"%s\" is reserved",
--- 227,233 ----
  					 errmsg("permission denied to create role")));
  	}
  
! 	if (strcasecmp(stmt->role, "public") == 0 || strcasecmp(stmt->role, "none") == 0)
  		ereport(ERROR,
  				(errcode(ERRCODE_RESERVED_NAME),
  				 errmsg("role name \"%s\" is reserved",
***************
*** 759,772 ****
  
  		roleid = HeapTupleGetOid(tuple);
  
! 		if (roleid == GetUserId())
  			ereport(ERROR,
  					(errcode(ERRCODE_OBJECT_IN_USE),
  					 errmsg("current role cannot be dropped")));
  		if (roleid == GetSessionUserId())
  			ereport(ERROR,
  					(errcode(ERRCODE_OBJECT_IN_USE),
! 					 errmsg("session role cannot be dropped")));
  
  		/*
  		 * For safety's sake, we allow createrole holders to drop ordinary
--- 759,776 ----
  
  		roleid = HeapTupleGetOid(tuple);
  
! 		if (roleid == GetCurrentRoleId())
  			ereport(ERROR,
  					(errcode(ERRCODE_OBJECT_IN_USE),
  					 errmsg("current role cannot be dropped")));
+ 		if (roleid == GetCurrentUserId())
+ 			ereport(ERROR,
+ 					(errcode(ERRCODE_OBJECT_IN_USE),
+ 					 errmsg("current user cannot be dropped")));
  		if (roleid == GetSessionUserId())
  			ereport(ERROR,
  					(errcode(ERRCODE_OBJECT_IN_USE),
! 					 errmsg("session user cannot be dropped")));
  
  		/*
  		 * For safety's sake, we allow createrole holders to drop ordinary
***************
*** 903,908 ****
--- 907,918 ----
  	int			i;
  	Oid			roleid;
  
+ 	if (strcasecmp(newname, "public") == 0 || strcasecmp(newname, "none") == 0)
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_RESERVED_NAME),
+ 				 errmsg("role name \"%s\" is reserved",
+ 						newname)));
+ 
  	/* ExclusiveLock because we need to update the flat auth file */
  	rel = heap_open(AuthIdRelationId, ExclusiveLock);
  	dsc = RelationGetDescr(rel);
***************
*** 919,933 ****
  	 * XXX Client applications probably store the session user somewhere,
  	 * so renaming it could cause confusion.  On the other hand, there may
  	 * not be an actual problem besides a little confusion, so think about
! 	 * this and decide.
  	 */
  
  	roleid = HeapTupleGetOid(oldtuple);
  
  	if (roleid == GetSessionUserId())
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 				 errmsg("session role may not be renamed")));
  
  	/* make sure the new name doesn't exist */
  	if (SearchSysCacheExists(AUTHNAME,
--- 929,953 ----
  	 * XXX Client applications probably store the session user somewhere,
  	 * so renaming it could cause confusion.  On the other hand, there may
  	 * not be an actual problem besides a little confusion, so think about
! 	 * this and decide.  Same for CurrentRole/CurrentUser?
  	 */
  
  	roleid = HeapTupleGetOid(oldtuple);
  
+ 	if (roleid == GetCurrentRoleId())
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ 				 errmsg("current role may not be renamed")));
+ 
+ 	if (roleid == GetCurrentUserId())
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ 				 errmsg("current user may not be renamed")));
+ 
  	if (roleid == GetSessionUserId())
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 				 errmsg("session user may not be renamed")));
  
  	/* make sure the new name doesn't exist */
  	if (SearchSysCacheExists(AUTHNAME,
***************
*** 1003,1012 ****
  	List	   *grantee_ids;
  	ListCell   *item;
  
  	if (stmt->grantor)
  		grantor = get_roleid_checked(stmt->grantor);
  	else
! 		grantor = GetUserId();
  
  	grantee_ids = roleNamesToIds(stmt->grantee_roles);
  
--- 1023,1040 ----
  	List	   *grantee_ids;
  	ListCell   *item;
  
+ 	/*
+ 	 * Per SQL spec, we use the 'GRANTED BY' role if one
+ 	 * is given, otherwise we use CURRENT_USER if set,
+ 	 * and CURRENT_ROLE if CURRENT_USER is not set.
+ 	 * For us, CURRENT_USER may never be *not* set.
+ 	 * (SQL spec also doesn't provide a way for it
+ 	 *  to ever become unset...)
+ 	 */
  	if (stmt->grantor)
  		grantor = get_roleid_checked(stmt->grantor);
  	else
! 		grantor = GetCurrentUserId();
  
  	grantee_ids = roleNamesToIds(stmt->grantee_roles);
  
Index: src/backend/commands/variable.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/commands/variable.c,v
retrieving revision 1.109
diff -c -r1.109 variable.c
*** src/backend/commands/variable.c	28 Jun 2005 05:08:55 -0000	1.109
--- src/backend/commands/variable.c	3 Jul 2005 05:11:18 -0000
***************
*** 564,569 ****
--- 564,682 ----
  
  
  /*
+  * SET ROLE
+  *
+  * When resetting session auth after an error, we can't expect to do catalog
+  * lookups.  Hence, the stored form of the value must provide a numeric oid
+  * that can be re-used directly.  We store the string in the form of
+  * NAMEDATALEN 'x's, followed by T or F to indicate superuserness, followed
+  * by the numeric oid, followed by a comma, followed by the role name.
+  * This cannot be confused with a plain role name because of the NAMEDATALEN
+  * limit on names, so we can tell whether we're being passed an initial
+  * role name or a saved/restored value.
+  */
+ extern char *role_string;		/* in guc.c */
+ 
+ const char *
+ assign_role(const char *value, bool doit, GucSource source)
+ {
+ 	Oid		roleid = InvalidOid;
+ 	bool		is_superuser = false;
+ 	const char *actual_rolename = value;
+ 	char	   *result;
+ 
+ 	if (strspn(value, "x") == NAMEDATALEN &&
+ 		(value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'))
+ 	{
+ 		/* might be a saved userid string */
+ 		Oid		savedoid;
+ 		char	   *endptr;
+ 
+ 		savedoid = (Oid) strtoul(value + NAMEDATALEN + 1, &endptr, 10);
+ 
+ 		if (endptr != value + NAMEDATALEN + 1 && *endptr == ',')
+ 		{
+ 			/* syntactically valid, so break out the data */
+ 			roleid = savedoid;
+ 			is_superuser = (value[NAMEDATALEN] == 'T');
+ 			actual_rolename = endptr + 1;
+ 		}
+ 	}
+ 
+ 	if (roleid == InvalidOid && strncmp(actual_rolename,"NONE",4) != 0)
+ 	{
+ 		/* not a saved ID, so look it up */
+ 		HeapTuple	roleTup;
+ 
+ 		if (!IsTransactionState())
+ 		{
+ 			/*
+ 			 * Can't do catalog lookups, so fail.  The upshot of this is
+ 			 * that role cannot be set in * postgresql.conf, which seems 
+ 			 * like a good thing anyway.
+ 			 */
+ 			return NULL;
+ 		}
+ 
+ 		roleTup = SearchSysCache(AUTHNAME,
+ 								 PointerGetDatum(value),
+ 								 0, 0, 0);
+ 		if (!HeapTupleIsValid(roleTup))
+ 		{
+ 			if (source >= PGC_S_INTERACTIVE)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_UNDEFINED_OBJECT),
+ 						 errmsg("role \"%s\" does not exist", value)));
+ 			return NULL;
+ 		}
+ 
+ 		roleid = HeapTupleGetOid(roleTup);
+ 		is_superuser = ((Form_pg_authid) GETSTRUCT(roleTup))->rolsuper;
+ 
+ 		ReleaseSysCache(roleTup);
+ 	}
+ 
+ 	if (doit)
+ 		SetCurrentRoleId(roleid);
+ 
+ 	result = (char *) malloc(NAMEDATALEN + 32 + strlen(actual_rolename));
+ 	if (!result)
+ 		return NULL;
+ 
+ 	memset(result, 'x', NAMEDATALEN);
+ 
+ 	sprintf(result + NAMEDATALEN, "%c%u,%s",
+ 			is_superuser ? 'T' : 'F',
+ 			roleid,
+ 			actual_rolename);
+ 
+ 	return result;
+ }
+ 
+ const char *
+ show_role(void)
+ {
+ 	/*
+ 	 * Extract the role name from the stored string; see
+ 	 * assign_role
+ 	 */
+ 	const char *value = role_string;
+ 	Oid		savedoid;
+ 	char	   *endptr;
+ 
+ 	if (!value || !value[0])
+ 		return "NONE";
+ 
+ 	Assert(strspn(value, "x") == NAMEDATALEN &&
+ 		   (value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'));
+ 
+ 	savedoid = (Oid) strtoul(value + NAMEDATALEN + 1, &endptr, 10);
+ 
+ 	Assert(endptr != value + NAMEDATALEN + 1 && *endptr == ',');
+ 
+ 	return endptr + 1;
+ }
+ /*
   * SET SESSION AUTHORIZATION
   *
   * When resetting session auth after an error, we can't expect to do catalog
Index: src/backend/parser/gram.y
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/parser/gram.y,v
retrieving revision 2.501
diff -c -r2.501 gram.y
*** src/backend/parser/gram.y	29 Jun 2005 20:34:13 -0000	2.501
--- src/backend/parser/gram.y	3 Jul 2005 05:11:18 -0000
***************
*** 396,402 ****
  	SERIALIZABLE SESSION SESSION_USER SET SETOF SHARE
  	SHOW SIMILAR SIMPLE SMALLINT SOME STABLE START STATEMENT
  	STATISTICS STDIN STDOUT STORAGE STRICT_P SUBSTRING SUPERUSER_P SYMMETRIC
! 	SYSID SYSTEM_P
  
  	TABLE TABLESPACE TEMP TEMPLATE TEMPORARY THEN TIME TIMESTAMP
  	TO TOAST TRAILING TRANSACTION TREAT TRIGGER TRIM TRUE_P
--- 396,402 ----
  	SERIALIZABLE SESSION SESSION_USER SET SETOF SHARE
  	SHOW SIMILAR SIMPLE SMALLINT SOME STABLE START STATEMENT
  	STATISTICS STDIN STDOUT STORAGE STRICT_P SUBSTRING SUPERUSER_P SYMMETRIC
! 	SYSID SYSTEM_P SYSTEM_USER
  
  	TABLE TABLESPACE TEMP TEMPLATE TEMPORARY THEN TIME TIMESTAMP
  	TO TOAST TRAILING TRANSACTION TREAT TRIGGER TRIM TRUE_P
***************
*** 1004,1009 ****
--- 1004,1019 ----
  						n->args = list_make1(makeStringConst($2, NULL));
  					$$ = n;
  				}
+ 			| ROLE ColId_or_Sconst
+ 				{
+ 					VariableSetStmt *n = makeNode(VariableSetStmt);
+ 					n->name = "role";
+ 					if (strncasecmp($2,"NONE",4))
+ 						n->args = NIL;
+ 					else
+ 						n->args = list_make1(makeStringConst($2, NULL));
+ 					$$ = n;
+ 				}
  			| SESSION AUTHORIZATION ColId_or_Sconst
  				{
  					VariableSetStmt *n = makeNode(VariableSetStmt);
***************
*** 1156,1161 ****
--- 1166,1177 ----
  					n->name = "transaction_isolation";
  					$$ = (Node *) n;
  				}
+ 			| SHOW ROLE
+ 				{
+ 					VariableShowStmt *n = makeNode(VariableShowStmt);
+ 					n->name = "role";
+ 					$$ = (Node *) n;
+ 				}
  			| SHOW SESSION AUTHORIZATION
  				{
  					VariableShowStmt *n = makeNode(VariableShowStmt);
***************
*** 7067,7073 ****
  			| CURRENT_ROLE
  				{
  					FuncCall *n = makeNode(FuncCall);
! 					n->funcname = SystemFuncName("current_user");
  					n->args = NIL;
  					n->agg_star = FALSE;
  					n->agg_distinct = FALSE;
--- 7083,7089 ----
  			| CURRENT_ROLE
  				{
  					FuncCall *n = makeNode(FuncCall);
! 					n->funcname = SystemFuncName("current_role");
  					n->args = NIL;
  					n->agg_star = FALSE;
  					n->agg_distinct = FALSE;
***************
*** 7091,7096 ****
--- 7107,7121 ----
  					n->agg_distinct = FALSE;
  					$$ = (Node *)n;
  				}
+ 			| SYSTEM_USER
+ 				{
+ 					FuncCall *n = makeNode(FuncCall);
+ 					n->funcname = SystemFuncName("system_user");
+ 					n->args = NIL;
+ 					n->agg_star = FALSE;
+ 					n->agg_distinct = FALSE;
+ 					$$ = (Node *)n;
+ 				}
  			| USER
  				{
  					FuncCall *n = makeNode(FuncCall);
***************
*** 8055,8061 ****
  			| RESTRICT
  			| RETURNS
  			| REVOKE
- 			| ROLE
  			| ROLLBACK
  			| ROWS
  			| RULE
--- 8080,8085 ----
***************
*** 8265,8270 ****
--- 8289,8295 ----
  			| SESSION_USER
  			| SOME
  			| SYMMETRIC
+ 			| SYSTEM_USER
  			| TABLE
  			| THEN
  			| TO
Index: src/backend/parser/keywords.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/parser/keywords.c,v
retrieving revision 1.162
diff -c -r1.162 keywords.c
*** src/backend/parser/keywords.c	29 Jun 2005 20:34:14 -0000	1.162
--- src/backend/parser/keywords.c	3 Jul 2005 05:11:18 -0000
***************
*** 313,318 ****
--- 313,319 ----
  	{"symmetric", SYMMETRIC},
  	{"sysid", SYSID},
  	{"system", SYSTEM_P},
+ 	{"system_user", SYSTEM_USER},
  	{"table", TABLE},
  	{"tablespace", TABLESPACE},
  	{"temp", TEMP},
Index: src/backend/utils/adt/name.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/name.c,v
retrieving revision 1.55
diff -c -r1.55 name.c
*** src/backend/utils/adt/name.c	31 Dec 2004 22:01:22 -0000	1.55
--- src/backend/utils/adt/name.c	3 Jul 2005 05:11:18 -0000
***************
*** 21,26 ****
--- 21,27 ----
  #include "postgres.h"
  
  #include "catalog/namespace.h"
+ #include "catalog/pg_authid.h"
  #include "catalog/pg_type.h"
  #include "libpq/pqformat.h"
  #include "mb/pg_wchar.h"
***************
*** 316,327 ****
  
  
  /*
!  * SQL-functions CURRENT_USER, SESSION_USER
   */
  Datum
  current_user(PG_FUNCTION_ARGS)
  {
! 	PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(GetUserNameFromId(GetUserId()))));
  }
  
  Datum
--- 317,342 ----
  
  
  /*
!  * SQL-functions CURRENT_ROLE, CURRENT_USER, SESSION_USER, SYSTEM_USER
   */
  Datum
+ current_role(PG_FUNCTION_ARGS)
+ {
+ 	char	*result = NULL;
+ 	Oid		roleid = GetCurrentRoleId();
+ 
+ 	if (roleid == InvalidOid)
+ 		result = "NONE";
+ 	else
+ 		result = GetUserNameFromId(roleid);
+ 
+ 	PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(result)));
+ }
+ 
+ Datum
  current_user(PG_FUNCTION_ARGS)
  {
! 	PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(GetUserNameFromId(GetCurrentUserId()))));
  }
  
  Datum
***************
*** 330,335 ****
--- 345,356 ----
  	PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(GetUserNameFromId(GetSessionUserId()))));
  }
  
+ Datum
+ system_user(PG_FUNCTION_ARGS)
+ {
+ 	PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(GetUserNameFromId(BOOTSTRAP_SUPERUSERID))));
+ }
+ 
  
  /*
   * SQL-functions CURRENT_SCHEMA, CURRENT_SCHEMAS
Index: src/backend/utils/init/miscinit.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/init/miscinit.c,v
retrieving revision 1.144
diff -c -r1.144 miscinit.c
*** src/backend/utils/init/miscinit.c	28 Jun 2005 22:16:45 -0000	1.144
--- src/backend/utils/init/miscinit.c	3 Jul 2005 05:11:18 -0000
***************
*** 35,40 ****
--- 35,41 ----
  #include "storage/fd.h"
  #include "storage/ipc.h"
  #include "storage/pg_shmem.h"
+ #include "utils/acl.h"
  #include "utils/builtins.h"
  #include "utils/guc.h"
  #include "utils/lsyscache.h"
***************
*** 264,269 ****
--- 265,271 ----
  static Oid AuthenticatedUserId = InvalidOid;
  static Oid SessionUserId = InvalidOid;
  static Oid CurrentUserId = InvalidOid;
+ static Oid CurrentRoleId = InvalidOid;
  
  static bool AuthenticatedUserIsSuperuser = false;
  
***************
*** 273,288 ****
  Oid
  GetUserId(void)
  {
  	AssertState(OidIsValid(CurrentUserId));
  	return CurrentUserId;
  }
  
  
  void
! SetUserId(Oid roleid)
  {
! 	AssertArg(OidIsValid(roleid));
! 	CurrentUserId = roleid;
  }
  
  
--- 275,328 ----
  Oid
  GetUserId(void)
  {
+ 	/* 
+ 	 * The SQL spec claims CurrentUserId does not have
+ 	 * to always be valid, but it is for us.  The spec
+ 	 * doesn't appear to say where it could possibly be
+ 	 * unset.
+ 	 */
+ 	AssertState(OidIsValid(CurrentUserId));
+ 
+ 	/*
+ 	 * CurrentRoleId is the top of the authorization 'stack'.
+ 	 */
+ 	if (OidIsValid(CurrentRoleId))
+ 		return CurrentRoleId;
+ 
+ 	/*
+ 	 * CurrentUserId is below CurrentRoleId on the stack and
+ 	 * so is only seen if CurrentRoleId is not set.
+ 	 * The SQL spec requires that CurrentRoleId or CurrentUserId
+ 	 * be valid at any given time.
+ 	 */
+ 	return CurrentUserId;
+ }
+ 
+ Oid
+ GetCurrentRoleId(void)
+ {
+ 	return CurrentRoleId;
+ }
+ 
+ Oid
+ GetCurrentUserId(void)
+ {
  	AssertState(OidIsValid(CurrentUserId));
  	return CurrentUserId;
  }
  
  
  void
! SetRoleId(Oid roleid)
  {
! 	CurrentRoleId = roleid;
! }
! 
! void
! SetUserId(Oid userid)
! {
! 	AssertArg(OidIsValid(userid));
! 	CurrentUserId = userid;
  }
  
  
***************
*** 298,310 ****
  
  
  void
! SetSessionUserId(Oid roleid)
  {
! 	AssertArg(OidIsValid(roleid));
! 	SessionUserId = roleid;
  	/* Current user defaults to session user. */
  	if (!OidIsValid(CurrentUserId))
! 		CurrentUserId = roleid;
  }
  
  
--- 338,353 ----
  
  
  void
! SetSessionUserId(Oid userid)
  {
! 	AssertArg(OidIsValid(userid));
! 	SessionUserId = userid;
  	/* Current user defaults to session user. */
  	if (!OidIsValid(CurrentUserId))
! 		CurrentUserId = userid;
! 
! 	/* Per SQL-spec, current role defaults to invalid */
! 	CurrentRoleId = InvalidOid;
  }
  
  
***************
*** 416,421 ****
--- 459,490 ----
  					PGC_INTERNAL, PGC_S_OVERRIDE);
  }
  
+ /*
+  * Change Role ID while running
+  *
+  * The current user must be in the role to which they want to change.
+  */
+ void
+ SetCurrentRoleId(Oid roleid)
+ {
+ 	/* 
+ 	 * May be called during startup to set to NONE, this doesn't
+ 	 * need a permission check anyway.
+ 	 */
+ 	if (roleid == InvalidOid)
+ 		return SetRoleId(roleid);
+ 
+ 	/* Must have authenticated already, else can't make permission check */
+ 	AssertState(OidIsValid(AuthenticatedUserId));
+ 
+ 	if (!is_member_of_role(GetCurrentUserId(),roleid))
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ 			  errmsg("permission denied to set current role")));
+ 
+ 	SetRoleId(roleid);
+ }
+ 
  
  /*
   * Get user name from user oid
Index: src/backend/utils/misc/check_guc
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/misc/check_guc,v
retrieving revision 1.8
diff -c -r1.8 check_guc
*** src/backend/utils/misc/check_guc	27 Jun 2003 19:08:38 -0000	1.8
--- src/backend/utils/misc/check_guc	3 Jul 2005 05:11:18 -0000
***************
*** 18,24 ****
  ## can be ignored
  INTENTIONALLY_NOT_INCLUDED="autocommit debug_deadlocks exit_on_error \
  is_superuser lc_collate lc_ctype lc_messages lc_monetary lc_numeric lc_time \
! pre_auth_delay seed server_encoding server_version session_authorization \
  trace_lock_oidmin trace_lock_table trace_locks trace_lwlocks trace_notify \
  trace_userlocks transaction_isolation transaction_read_only \
  zero_damaged_pages"
--- 18,24 ----
  ## can be ignored
  INTENTIONALLY_NOT_INCLUDED="autocommit debug_deadlocks exit_on_error \
  is_superuser lc_collate lc_ctype lc_messages lc_monetary lc_numeric lc_time \
! pre_auth_delay role seed server_encoding server_version session_authorization \
  trace_lock_oidmin trace_lock_table trace_locks trace_lwlocks trace_notify \
  trace_userlocks transaction_isolation transaction_read_only \
  zero_damaged_pages"
Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/misc/guc.c,v
retrieving revision 1.271
diff -c -r1.271 guc.c
*** src/backend/utils/misc/guc.c	28 Jun 2005 05:09:02 -0000	1.271
--- src/backend/utils/misc/guc.c	3 Jul 2005 05:11:18 -0000
***************
*** 195,200 ****
--- 195,203 ----
  /* should be static, but commands/variable.c needs to get at it */
  char	   *session_authorization_string;
  
+ /* should be static, but commands/variable.c needs to get at it */
+ char	   *role_string;
+ 
  
  /*
   * Displayable names for context types (enum GucContext)
***************
*** 1751,1756 ****
--- 1754,1770 ----
  	},
  
  	{
+ 		/* Not for general use --- used by SET ROLE */
+ 		{"role", PGC_USERSET, UNGROUPED,
+ 			gettext_noop("Sets the current role."),
+ 			NULL,
+ 			GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+ 		},
+ 		&role_string,
+ 		"NONE", assign_role, show_role
+ 	},
+ 
+ 	{
  		/* Not for general use --- used by SET SESSION AUTHORIZATION */
  		{"session_authorization", PGC_USERSET, UNGROUPED,
  			gettext_noop("Sets the session user name."),
Index: src/include/miscadmin.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/miscadmin.h,v
retrieving revision 1.176
diff -c -r1.176 miscadmin.h
*** src/include/miscadmin.h	28 Jun 2005 05:09:04 -0000	1.176
--- src/include/miscadmin.h	3 Jul 2005 05:11:18 -0000
***************
*** 229,238 ****
--- 229,292 ----
  extern void SetDatabasePath(const char *path);
  
  extern char *GetUserNameFromId(Oid roleid);
+ /* 
+  * GetUserId will return the authorization identifier on the top
+  * of the authorization 'stack'.  That is to say, the CURRENT_ROLE
+  * if it is set, the CURRENT_USER if CURRENT_ROLE is not set.
+  */
  extern Oid GetUserId(void);
+ 
+ /* 
+  * Returns the CURRENT_ROLE Oid, this may not be set!  Use GetUserId()
+  * if you need something which is always expected to be valid
+  */
+ extern Oid GetCurrentRoleId(void);
+ 
+ /*
+  * Sets the CURRENT_ROLE authorization identifier, this is the top
+  * of the 'stack' and will be used until it is reset to InvalidOid.
+  * Does not do authorization checks, use SetCurrentRoleId() instead.
+  * (Which can be done with SET ROLE NONE;)
+  */
+ extern void SetRoleId(Oid roleid);
+ 
+ /* 
+  * Returns the CURRENT_USER Oid, SQL spec claims this may not always
+  * be set but doesn't identify a case where it could be unset, this
+  * should *not* be used directly for authorization generally, use
+  * GetUserId() which understands the authorization 'stack'.
+  * This is used by GRANT operations for the grantor, per SQL spec.
+  */
+ extern Oid GetCurrentUserId(void);
+ 
+ /*
+  * Sets the CURRENT_USER authorization identifier, this should
+  * generally be able to be done only by the superuser.
+  */
  extern void SetUserId(Oid roleid);
+ 
+ /* 
+  * Returns the SESSION_USER Oid, SQL spec requires this always be
+  * set, however it should not be used directly for authorization,
+  * use GetUserId() instead
+  */
  extern Oid GetSessionUserId(void);
+ 
+ /*
+  * Sets the CURRENT_ROLE authorization identifier, this is the top
+  * of the 'stack' and will be used until it is reset to InvalidOid
+  * Does authorization checks.
+  * (Which can be done with SET ROLE NONE;)
+  */
+ extern void SetCurrentRoleId(Oid roleid);
+ 
+ /*
+  * Sets the SESSION_USER authorization identifier, this should
+  * generally be able to be done only by the superuser.
+  * Does authorization checks.
+  */
  extern void SetSessionUserId(Oid roleid);
+ 
  extern void InitializeSessionUserId(const char *rolename);
  extern void InitializeSessionUserIdStandalone(void);
  extern void SetSessionAuthorization(Oid roleid, bool is_superuser);
Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/catalog/pg_proc.h,v
retrieving revision 1.373
diff -c -r1.373 pg_proc.h
*** src/include/catalog/pg_proc.h	1 Jul 2005 19:19:03 -0000	1.373
--- src/include/catalog/pg_proc.h	3 Jul 2005 05:11:19 -0000
***************
*** 1003,1012 ****
--- 1003,1016 ----
  DATA(insert OID = 743 (  text_ge		   PGNSP PGUID 12 f f t f i 2 16 "25 25" _null_ _null_ _null_ text_ge - _null_ ));
  DESCR("greater-than-or-equal");
  
+ DATA(insert OID = 1136 (  current_role	   PGNSP PGUID 12 f f t f s 0 19 "" _null_ _null_ _null_ current_role - _null_ ));
+ DESCR("current role name");
  DATA(insert OID = 745 (  current_user	   PGNSP PGUID 12 f f t f s 0 19 "" _null_ _null_ _null_ current_user - _null_ ));
  DESCR("current user name");
  DATA(insert OID = 746 (  session_user	   PGNSP PGUID 12 f f t f s 0 19 "" _null_ _null_ _null_ session_user - _null_ ));
  DESCR("session user name");
+ DATA(insert OID = 1137 (  system_user	   PGNSP PGUID 12 f f t f s 0 19 "" _null_ _null_ _null_ system_user - _null_ ));
+ DESCR("system user name");
  
  DATA(insert OID = 744 (  array_eq		   PGNSP PGUID 12 f f t f i 2 16 "2277 2277" _null_ _null_ _null_ array_eq - _null_ ));
  DESCR("array equal");
Index: src/include/commands/variable.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/commands/variable.h,v
retrieving revision 1.25
diff -c -r1.25 variable.h
*** src/include/commands/variable.h	31 Dec 2004 22:03:28 -0000	1.25
--- src/include/commands/variable.h	3 Jul 2005 05:11:19 -0000
***************
*** 26,31 ****
--- 26,34 ----
  extern const char *show_random_seed(void);
  extern const char *assign_client_encoding(const char *value,
  					   bool doit, GucSource source);
+ extern const char *assign_role(const char *value,
+ 							 bool doit, GucSource source);
+ extern const char *show_role(void);
  extern const char *assign_session_authorization(const char *value,
  							 bool doit, GucSource source);
  extern const char *show_session_authorization(void);
Index: src/include/utils/builtins.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/utils/builtins.h,v
retrieving revision 1.258
diff -c -r1.258 builtins.h
*** src/include/utils/builtins.h	17 Jun 2005 22:32:50 -0000	1.258
--- src/include/utils/builtins.h	3 Jul 2005 05:11:19 -0000
***************
*** 207,214 ****
--- 207,216 ----
  extern int	namecpy(Name n1, Name n2);
  extern int	namestrcpy(Name name, const char *str);
  extern int	namestrcmp(Name name, const char *str);
+ extern Datum current_role(PG_FUNCTION_ARGS);
  extern Datum current_user(PG_FUNCTION_ARGS);
  extern Datum session_user(PG_FUNCTION_ARGS);
+ extern Datum system_user(PG_FUNCTION_ARGS);
  extern Datum current_schema(PG_FUNCTION_ARGS);
  extern Datum current_schemas(PG_FUNCTION_ARGS);