Implement differentiation between CURRENT_USER and SESSION_USER as per SQL.

There is still no effective difference but it will kick in once setuid
functions exist (not included here).  Make old getpgusername() alias for
current_user.

3 files changed, 79 insertions, 39 deletions

diff --git a/src/backend/utils/adt/name.c b/src/backend/utils/adt/name.c
index 3acf40e0d4..edc14303d4 100644
--- a/src/backend/utils/adt/name.c
+++ b/src/backend/utils/adt/name.c
@@ -12,7 +12,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/name.c,v 1.29 2000/08/03 16:34:22 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/name.c,v 1.30 2000/09/19 18:17:56 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -136,13 +136,6 @@ namege(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(strncmp(NameStr(*arg1), NameStr(*arg2), NAMEDATALEN) >= 0);
 }
 
-/* SQL-function interface to GetPgUserName() */
-Datum
-getpgusername(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_DATUM(DirectFunctionCall1(namein,
-										CStringGetDatum(GetPgUserName())));
-}
 
 /* (see char.c for comparison/operation routines) */
 
@@ -218,6 +211,21 @@ namestrcmp(Name name, const char *str)
 	return strncmp(NameStr(*name), str, NAMEDATALEN);
 }
 
+
+/* SQL-functions CURRENT_USER and SESSION_USER */
+Datum
+current_user(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(GetUserName(GetUserId()))));
+}
+
+Datum
+session_user(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(GetUserName(GetSessionUserId()))));
+}
+
+
 /*****************************************************************************
  *	 PRIVATE ROUTINES														 *
  *****************************************************************************/
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index 20babcc616..0974a05715 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.54 2000/09/06 14:15:22 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.55 2000/09/19 18:17:57 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -272,50 +272,65 @@ convertstr(unsigned char *buff, int len, int dest)
 
 #endif
 
-/* ----------------
- *		GetPgUserName
- * ----------------
- */
-char *
-GetPgUserName(void)
-{
-	HeapTuple tuple;
-	Oid userid;
-
-	userid = GetUserId();
-
-	tuple = SearchSysCacheTuple(SHADOWSYSID, ObjectIdGetDatum(userid), 0, 0, 0);
-	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "invalid user id %u", (unsigned) userid);
-
-	return pstrdup( NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename) );
-}
 
 
 /* ----------------------------------------------------------------
- *		GetUserId and SetUserId
+ * 	User ID things
+ *
+ * The session user is determined at connection start and never
+ * changes.  The current user may change when "setuid" functions
+ * are implemented.  Conceptually there is a stack, whose bottom
+ * is the session user.  You are yourself responsible to save and
+ * restore the current user id if you need to change it.
  * ----------------------------------------------------------------
  */
-static Oid	UserId = InvalidOid;
+static Oid	CurrentUserId = InvalidOid;
+static Oid	SessionUserId = InvalidOid;
 
 
+/*
+ * This function is relevant for all privilege checks.
+ */
 Oid
-GetUserId()
+GetUserId(void)
 {
-	AssertState(OidIsValid(UserId));
-	return UserId;
+	AssertState(OidIsValid(CurrentUserId));
+	return CurrentUserId;
 }
 
 
 void
 SetUserId(Oid newid)
 {
-	UserId = newid;
+	AssertArg(OidIsValid(newid));
+	CurrentUserId = newid;
+}
+
+
+/*
+ * This value is only relevant for informational purposes.
+ */
+Oid
+GetSessionUserId(void)
+{
+	AssertState(OidIsValid(SessionUserId));
+	return SessionUserId;
+}
+
+
+void
+SetSessionUserId(Oid newid)
+{
+	AssertArg(OidIsValid(newid));
+	SessionUserId = newid;
+	/* Current user defaults to session user. */
+	if (!OidIsValid(CurrentUserId))
+		CurrentUserId = newid;
 }
 
 
 void
-SetUserIdFromUserName(const char *username)
+SetSessionUserIdFromUserName(const char *username)
 {
 	HeapTuple	userTup;
 
@@ -330,13 +345,30 @@ SetUserIdFromUserName(const char *username)
 								  0, 0, 0);
 	if (!HeapTupleIsValid(userTup))
 		elog(FATAL, "user \"%s\" does not exist", username);
-	SetUserId( ((Form_pg_shadow) GETSTRUCT(userTup))->usesysid );
+	SetSessionUserId( ((Form_pg_shadow) GETSTRUCT(userTup))->usesysid );
 }
 
 
+/*
+ * Get user name from user id
+ */
+char *
+GetUserName(Oid userid)
+{
+	HeapTuple tuple;
+
+	tuple = SearchSysCacheTuple(SHADOWSYSID, ObjectIdGetDatum(userid), 0, 0, 0);
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "invalid user id %u", (unsigned) userid);
+
+	return pstrdup( NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename) );
+}
+
+
+
 /*-------------------------------------------------------------------------
  *
- * posmaster pid file stuffs. $DATADIR/postmaster.pid is created when:
+ * postmaster pid file stuffs. $DATADIR/postmaster.pid is created when:
  *
  *	(1) postmaster starts. In this case pid > 0.
  *	(2) postgres starts in standalone mode. In this case
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index a9e083557e..c0502d99ab 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.65 2000/09/06 14:15:22 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.66 2000/09/19 18:17:57 petere Exp $
  *
  *
  *-------------------------------------------------------------------------
@@ -374,9 +374,9 @@ InitPostgres(const char *dbname, const char *username)
 	 * user id.
 	 */
 	if (bootstrap)
-		SetUserId(geteuid());
+		SetSessionUserId(geteuid());
 	else
-		SetUserIdFromUserName(username);
+		SetSessionUserIdFromUserName(username);
 
 	setuid(geteuid());