From e204b9532b974a8655018ae89709b26bfc9c1d64 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Sun, 19 Nov 2017 23:24:18 +0100
Subject: [PATCH] rom_filter: allow use of input as attribute value

---
 repos/os/src/server/rom_filter/README  |  5 +++++
 repos/os/src/server/rom_filter/main.cc | 27 +++++++++++++++++++++++---
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/repos/os/src/server/rom_filter/README b/repos/os/src/server/rom_filter/README
index d737326b8..07fbe10aa 100644
--- a/repos/os/src/server/rom_filter/README
+++ b/repos/os/src/server/rom_filter/README
@@ -34,6 +34,11 @@ The '<output>' node can contain the following sub nodes:
   Copies all sub nodes named by the 'sub_node' attribute of the input ROM
   specified by the 'name' attribute to the output node.
 
+:'<attribute>':
+  Adds an attribute with the specified 'name' and 'value'. If the node
+  has an 'input' attribute, the content of the specified input is taken
+  as attribute value.
+
 
 Conditions
 ----------
diff --git a/repos/os/src/server/rom_filter/main.cc b/repos/os/src/server/rom_filter/main.cc
index bd96bdde0..b57879bd2 100644
--- a/repos/os/src/server/rom_filter/main.cc
+++ b/repos/os/src/server/rom_filter/main.cc
@@ -283,10 +283,31 @@ void Rom_filter::Main::_evaluate_node(Xml_node node, Xml_generator &xml)
 		} else
 
 		if (node.has_type("attribute")) {
+
 			typedef Genode::String<128> String;
-			xml.attribute(
-				node.attribute_value("name", String()).string(),
-				node.attribute_value("value", String()).string());
+
+			/* assign input value to attribute value */
+			if (node.has_attribute("input")) {
+
+				Input_name const input_name =
+					node.attribute_value("input", Input_name());
+				try {
+					Input_value const input_value =
+						_input_rom_registry.query_value(_config.xml(), input_name);
+
+					xml.attribute(node.attribute_value("name", String()).string(),
+					              input_value);
+				}
+				catch (Input_rom_registry::Nonexistent_input_value) {
+					Genode::warning("could not obtain input value for input ", input_name);
+				}
+			}
+
+			/* assign fixed attribute value */
+			else {
+				xml.attribute(node.attribute_value("name",  String()).string(),
+				              node.attribute_value("value", String()).string());
+			}
 		} else
 
 		if (node.has_type("inline")) {