[Firebird-checkins] SF.net SVN: firebird:[60183] firebird/trunk/src/jrd/vio.cpp

[<di...@us...>]

Revision: 60183
          http://sourceforge.net/p/firebird/code/60183
Author:   dimitr
Date:     2014-11-09 16:40:52 +0000 (Sun, 09 Nov 2014)
Log Message:
-----------
Relaxed system tables protection for cases UPDATE ... SET RDB$*_SOURCE = NULL. So far nullification is allowed for views/packages/procedures/functions/triggers only. I'm not sure somebody really needs hiding sources for defaults and check constraints, but this can be supported later, if required. This is a temporary solution, intended to be replaced with something more clever (e.g. special permissions or new DDL command) in v4.

Modified Paths:
--------------
    firebird/trunk/src/jrd/vio.cpp

Modified: firebird/trunk/src/jrd/vio.cpp
===================================================================
--- firebird/trunk/src/jrd/vio.cpp	2014-11-09 14:47:08 UTC (rev 60182)
+++ firebird/trunk/src/jrd/vio.cpp	2014-11-09 16:40:52 UTC (rev 60183)
@@ -95,6 +95,7 @@
 using namespace Firebird;
 
 static void check_class(thread_db*, jrd_tra*, record_param*, record_param*, USHORT);
+static bool check_nullify_source(record_param*, record_param*, USHORT);
 static void check_owner(thread_db*, jrd_tra*, record_param*, record_param*, USHORT);
 static bool check_user(thread_db*, const dsc*);
 static int check_precommitted(const jrd_tra*, const record_param*);
@@ -2501,7 +2502,8 @@
 			break;
 
 		case rel_relations:
-			protect_system_table_delupd(tdbb, relation, "UPDATE");
+			if (!check_nullify_source(org_rpb, new_rpb, f_rel_source))
+				protect_system_table_delupd(tdbb, relation, "UPDATE");
 			EVL_field(0, org_rpb->rpb_record, f_rel_name, &desc1);
 			SCL_check_relation(tdbb, &desc1, SCL_alter);
 			check_class(tdbb, transaction, org_rpb, new_rpb, f_rel_class);
@@ -2510,7 +2512,8 @@
 			break;
 
 		case rel_packages:
-			protect_system_table_delupd(tdbb, relation, "UPDATE");
+			if (!check_nullify_source(org_rpb, new_rpb, f_pkg_header_source))
+				protect_system_table_delupd(tdbb, relation, "UPDATE");
 			if (EVL_field(0, org_rpb->rpb_record, f_pkg_name, &desc1))
 				SCL_check_package(tdbb, &desc1, SCL_alter);
 			check_class(tdbb, transaction, org_rpb, new_rpb, f_pkg_class);
@@ -2518,7 +2521,8 @@
 			break;
 
 		case rel_procedures:
-			protect_system_table_delupd(tdbb, relation, "UPDATE");
+			if (!check_nullify_source(org_rpb, new_rpb, f_prc_source))
+				protect_system_table_delupd(tdbb, relation, "UPDATE");
 			EVL_field(0, org_rpb->rpb_record, f_prc_name, &desc1);
 
 			if (EVL_field(0, org_rpb->rpb_record, f_prc_pkg_name, &desc2))
@@ -2543,7 +2547,8 @@
 			break;
 
 		case rel_funs:
-			protect_system_table_delupd(tdbb, relation, "UPDATE");
+			if (!check_nullify_source(org_rpb, new_rpb, f_fun_source))
+				protect_system_table_delupd(tdbb, relation, "UPDATE");
 			EVL_field(0, org_rpb->rpb_record, f_fun_name, &desc1);
 
 			if (EVL_field(0, org_rpb->rpb_record, f_fun_pkg_name, &desc2))
@@ -2670,7 +2675,8 @@
 			break;
 
 		case rel_triggers:
-			protect_system_table_delupd(tdbb, relation, "UPDATE");
+			if (!check_nullify_source(org_rpb, new_rpb, f_trg_source))
+				protect_system_table_delupd(tdbb, relation, "UPDATE");
 			EVL_field(0, new_rpb->rpb_record, f_trg_rname, &desc1);
 			SCL_check_relation(tdbb, &desc1, SCL_control);
 
@@ -4057,6 +4063,45 @@
 }
 
 
+/**************************************
+ *
+ *	c h e c k _ n u l l i f y _ s o u r c e
+ *
+ **************************************
+ *
+ * Functional description
+ *	A record in a system relation containing a source blob is
+ *	being changed.  Check to see if only the source blob has changed,
+ *	and if so, validate whether it was an assignment to NULL.
+ *
+ **************************************/
+static bool check_nullify_source(record_param* org_rpb, record_param* new_rpb, USHORT field_id)
+{
+	bool nullify_found = false;
+
+	dsc org_desc, new_desc;
+	for (USHORT iter = 0; iter < org_rpb->rpb_record->rec_format->fmt_count; ++iter)
+	{
+		const bool org_null = !EVL_field(NULL, org_rpb->rpb_record, iter, &org_desc);
+		const bool new_null = !EVL_field(NULL, new_rpb->rpb_record, iter, &new_desc);
+
+		if (iter == field_id && new_null)
+		{
+			fb_assert(org_desc.dsc_dtype == dtype_blob);
+			fb_assert(new_desc.dsc_dtype == dtype_blob);
+
+			nullify_found = true;
+			continue;
+		}
+
+		if (org_null != new_null || MOV_compare(&org_desc, &new_desc))
+			return false;
+	}
+
+	return nullify_found;
+}
+
+
 static void check_owner(thread_db* tdbb,
 						jrd_tra* transaction,
 						record_param* old_rpb, record_param* new_rpb, USHORT id)

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