Propagate session diag flag to core

This commit restores the diag feature for selecting diagnostic output of
services provided by core. This feature became unavailable with commit
"base: remove dependency from deprecated APIs", which hard-wired the
diag flag for core services to false.

To control this feature, three possible policies can be expressed in a
routing target of init's configuration:

* Forcing silence by specifying 'diag="no"'
* Enabling diagnostics by specifying 'diag="yes"'
* Forwarding the preference of the client by omitting the 'diag'
  attribute

Fixes #3962

repos/base/include/base/child.h

@@ -83,7 +83,8 @@ struct Genode::Child_policy
 	 * \throw Service_denied
 	 */
 	virtual Route resolve_session_request(Service::Name const &,
-	                                      Session_label const &) = 0;
+	                                      Session_label const &,
+	                                      Session::Diag) = 0;
 
 	/**
 	 * Apply transformations to session arguments
@@ -575,7 +576,8 @@ class Genode::Child : protected Rpc_object<Parent>,
 				try {
 					Child_policy::Route const route =
 						_child._policy.resolve_session_request(_service_name(),
-						                                       label_from_args(_args.string()));
+						                                       label_from_args(_args.string()),
+						                                       session_diag_from_args(_args.string()));
 					_env_service.construct(_child, route.service);
 					_connection.construct(*_env_service, _child._id_space, _client_id,
 					                      _args, _child._policy.filter_session_affinity(Affinity()),

repos/base/include/base/local_connection.h

@@ -68,7 +68,7 @@ struct Genode::Local_connection_base : Noncopyable
 		{
 			enum { NUM_ATTEMPTS = 10 };
 			for (unsigned i = 0; i < NUM_ATTEMPTS; i++) {
-				_session_state.construct(service, id_space, id, label,
+				_session_state.construct(service, id_space, id, label, diag,
 				                         _init_args(args, resources, diag),
 				                         affinity);
 

repos/base/include/base/session_state.h

@@ -65,6 +65,7 @@ class Genode::Session_state : public Parent::Client, public Parent::Server
 		Reconstructible<Id_space<Parent::Client>::Element> _id_at_client;
 
 		Session::Label const _label;
+		Session::Diag  const _diag;
 		Args                 _args;
 		Affinity             _affinity;
 
@@ -138,6 +139,7 @@ class Genode::Session_state : public Parent::Client, public Parent::Server
 		              Id_space<Parent::Client> &client_id_space,
 		              Parent::Client::Id        client_id,
 		              Session::Label     const &label,
+		              Session::Diag             diag,
 		              Args               const &args,
 		              Affinity           const &affinity);
 
@@ -179,6 +181,8 @@ class Genode::Session_state : public Parent::Client, public Parent::Server
 
 		Args const &args() const { return _args; }
 
+		Session::Diag diag() const { return _diag; }
+
 		Affinity const &affinity() const { return _affinity; }
 
 		void generate_session_request(Xml_generator &) const;

repos/base/lib/symbols/ld

@@ -92,8 +92,8 @@ _ZN6Genode13Registry_base7_insertERNS0_7ElementE T
 _ZN6Genode13Registry_base7_removeERNS0_7ElementE T
 _ZN6Genode13Registry_base9_for_eachERNS0_15Untyped_functorE T
 _ZN6Genode13Session_state7destroyEv T
-_ZN6Genode13Session_stateC1ERNS_7ServiceERNS_8Id_spaceINS_6Parent6ClientEEENS6_2IdERKNS_13Session_labelERKNS_6StringILm256EEERKNS_8AffinityE T
+_ZN6Genode13Session_stateC1ERNS_7ServiceERNS_8Id_spaceINS_6Parent6ClientEEENS6_2IdERKNS_13Session_labelENS_7Session4DiagERKNS_6StringILm256EEERKNS_8AffinityE T
-_ZN6Genode13Session_stateC2ERNS_7ServiceERNS_8Id_spaceINS_6Parent6ClientEEENS6_2IdERKNS_13Session_labelERKNS_6StringILm256EEERKNS_8AffinityE T
+_ZN6Genode13Session_stateC2ERNS_7ServiceERNS_8Id_spaceINS_6Parent6ClientEEENS6_2IdERKNS_13Session_labelENS_7Session4DiagERKNS_6StringILm256EEERKNS_8AffinityE T
 _ZN6Genode13Shared_objectC1ERNS_3EnvERNS_9AllocatorEPKcNS0_4BindENS0_4KeepE T
 _ZN6Genode13Shared_objectC2ERNS_3EnvERNS_9AllocatorEPKcNS0_4BindENS0_4KeepE T
 _ZN6Genode13Shared_objectD1Ev T

repos/base/src/core/main.cc

@@ -146,7 +146,8 @@ class Core_child : public Child_policy
 		Name name() const override { return "init"; }
 
 		Route resolve_session_request(Service::Name const &name,
-		                              Session_label const &label) override
+		                              Session_label const &label,
+		                              Session::Diag const  diag) override
 		{
 			Service *service = nullptr;
 			_services.for_each([&] (Service &s) {
@@ -158,7 +159,7 @@ class Core_child : public Child_policy
 
 			return Route { .service = *service,
 			               .label   = label,
-			               .diag    = Session::Diag() };
+			               .diag    = diag };
 		}
 
 		void init(Pd_session &session, Capability<Pd_session> cap) override

repos/base/src/lib/base/child.cc

@@ -100,13 +100,13 @@ void Child::session_sigh(Signal_context_capability sigh)
  */
 Session_state &
 create_session(Child_policy::Name const &child_name, Service &service,
-               Session_label const &label,
+               Session_label const &label, Session::Diag diag,
                Session_state::Factory &factory, Id_space<Parent::Client> &id_space,
                Parent::Client::Id id, Session_state::Args const &args,
                Affinity const &affinity)
 {
 	try {
-		return service.create_session(factory, id_space, id, label, args, affinity); }
+		return service.create_session(factory, id_space, id, label, diag, args, affinity); }
 
 	catch (Insufficient_ram_quota) {
 		error(child_name, " requested session with insufficient RAM quota");
@@ -174,7 +174,9 @@ Session_capability Child::session(Parent::Client::Id id,
 	Arg_string::set_arg(argbuf, sizeof(argbuf), "ram_quota", forward_ram_quota.value);
 
 	/* may throw a 'Service_denied' exception */
-	Child_policy::Route route = _policy.resolve_session_request(name.string(), label);
+	Child_policy::Route route =
+		_policy.resolve_session_request(name.string(), label,
+		                                session_diag_from_args(argbuf));
 
 	Service &service = route.service;
 
@@ -182,7 +184,7 @@ Session_capability Child::session(Parent::Client::Id id,
 	Arg_string::set_arg(argbuf, sizeof(argbuf), "diag", route.diag.enabled);
 
 	Session_state &session =
-		create_session(_policy.name(), service, route.label,
+		create_session(_policy.name(), service, route.label, route.diag,
 		               _session_factory, _id_space, id, argbuf, filtered_affinity);
 
 	_policy.session_state_changed();

repos/base/src/lib/base/session_state.cc

@@ -172,6 +172,7 @@ Session_state::Session_state(Service                  &service,
                              Id_space<Parent::Client> &client_id_space,
                              Parent::Client::Id        client_id,
                              Session::Label     const &label,
+                             Session::Diag      const  diag,
                              Args const               &args,
                              Affinity           const &affinity)
 :
@@ -179,5 +180,5 @@ Session_state::Session_state(Service                  &service,
 	_donated_ram_quota(ram_quota_from_args(args.string())),
 	_donated_cap_quota(cap_quota_from_args(args.string())),
 	_id_at_client(*this, client_id_space, client_id),
-	_label(label), _args(args), _affinity(affinity)
+	_label(label), _diag(diag), _args(args), _affinity(affinity)
 { }

repos/base/src/test/rm_fault/main.cc

@@ -230,11 +230,12 @@ class Test_child_policy : public Child_policy
 		}
 
 		Route resolve_session_request(Service::Name const &name,
-		                              Session_label const &label) override
+		                              Session_label const &label,
+		                              Session::Diag const  diag) override
 		{
 			return Route { .service = _matching_service(name),
 			               .label   = label,
-			               .diag    = Session::Diag() };
+			               .diag    = diag };
 		}
 };
 

repos/demo/include/launchpad/launchpad.h

@@ -153,12 +153,13 @@ class Launchpad_child : public  Genode::Child_policy,
 
 		Genode::Child_policy::Route
 		resolve_session_request(Genode::Service::Name const &service_name,
-		                        Genode::Session_label const &label) override
+		                        Genode::Session_label const &label,
+		                        Genode::Session::Diag const  diag) override
 		{
 			auto route = [&] (Genode::Service &service) {
 				return Genode::Child_policy::Route { .service = service,
 				                                     .label   = label,
-				                                     .diag    = Genode::Session::Diag() }; };
+				                                     .diag    = diag }; };
 
 			Genode::Service *service = nullptr;
 

repos/libports/src/lib/libc/fork.cc

@@ -474,7 +474,8 @@ struct Libc::Forked_child : Child_policy, Child_ready
 	}
 
 	Route resolve_session_request(Service::Name const &name,
-	                              Session_label const &label) override
+	                              Session_label const &label,
+	                              Session::Diag const  diag) override
 	{
 		Session_label rewritten_label = label;
 
@@ -508,7 +509,7 @@ struct Libc::Forked_child : Child_policy, Child_ready
 		if (service_ptr)
 			return Route { .service = *service_ptr,
 			               .label   = rewritten_label,
-			               .diag    = Session::Diag() };
+			               .diag    = diag };
 
 		throw Service_denied();
 	}

repos/os/include/os/slave.h

@@ -164,11 +164,12 @@ class Genode::Slave::Policy : public Child_policy
 		}
 
 		Route resolve_session_request(Service::Name const &name,
-		                              Session_label const &label) override
+		                              Session_label const &label,
+		                              Session::Diag const  diag) override
 		{
 			return Route { .service = _matching_service(name, label),
 			               .label   = label,
-			               .diag    = Session::Diag() };
+			               .diag    = diag };
 		}
 
 		Id_space<Parent::Server> &server_id_space() override {

repos/os/src/app/sequence/main.cc

@@ -114,12 +114,13 @@ struct Sequence::Child : Genode::Child_policy
 	 * otherwise forward directly to the parent.
 	 */
 	Route resolve_session_request(Service::Name const &name,
-	                              Session_label const &label) override
+	                              Session_label const &label,
+	                              Session::Diag const  diag) override
 	{
 		auto route = [&] (Service &service) {
 			return Route { .service = service,
 			               .label   = label,
-			               .diag    = Session::Diag() }; };
+			               .diag    = diag }; };
 
 		if (_have_config) {
 			Service *s =

repos/os/src/lib/sandbox/child.cc

@@ -446,7 +446,8 @@ void Sandbox::Child::init(Cpu_session &session, Cpu_session_capability cap)
 
 Sandbox::Child::Route
 Sandbox::Child::resolve_session_request(Service::Name const &service_name,
-                                        Session_label const &label)
+                                        Session_label const &label,
+                                        Session::Diag const  diag)
 {
 	/* check for "config" ROM request */
 	if (service_name == Rom_session::service_name() &&
@@ -474,17 +475,16 @@ Sandbox::Child::resolve_session_request(Service::Name const &service_name,
 	 */
 	if (service_name == Rom_session::service_name() &&
 	    label == _unique_name && _unique_name != _binary_name)
-		return resolve_session_request(service_name, _binary_name);
+		return resolve_session_request(service_name, _binary_name, diag);
 
 	/* supply binary as dynamic linker if '<start ld="no">' */
 	if (!_use_ld && service_name == Rom_session::service_name() && label == "ld.lib.so")
-		return resolve_session_request(service_name, _binary_name);
+		return resolve_session_request(service_name, _binary_name, diag);
 
 	/* check for "session_requests" ROM request */
 	if (service_name == Rom_session::service_name()
 	 && label.last_element() == Session_requester::rom_name())
-		return Route { _session_requester.service(),
+		return Route { _session_requester.service(), Session::Label(), diag };
-		               Session::Label(), Session::Diag{false} };
 
 	try {
 		Xml_node route_node = _default_route_accessor.default_route();
@@ -517,7 +517,7 @@ Sandbox::Child::resolve_session_request(Service::Name const &service_name,
 					target.attribute_value("label", Label(label.string()));
 
 				Session::Diag const
-					target_diag { target.attribute_value("diag", false) };
+					target_diag { target.attribute_value("diag", diag.enabled) };
 
 				auto no_filter = [] (Service &) -> bool { return false; };
 

repos/os/src/lib/sandbox/child.h

@@ -385,7 +385,8 @@ class Sandbox::Child : Child_policy, Routed_service::Wakeup
 			try {
 				Route const route =
 					resolve_session_request(session.service().name(),
-					                        session.client_label());
+					                        session.client_label(),
+					                        session.diag());
 
 				return (session.service() == route.service)
 				    && (route.label == session.label());
@@ -599,7 +600,7 @@ class Sandbox::Child : Child_policy, Routed_service::Wakeup
 			return _session_requester.id_space(); }
 
 		Route resolve_session_request(Service::Name const &,
-		                              Session_label const &) override;
+		                              Session_label const &, Session::Diag) override;
 
 		void     filter_session_args(Service::Name const &, char *, size_t) override;
 		Affinity filter_session_affinity(Affinity const &) override;

repos/os/src/lib/sandbox/server.cc

@@ -226,10 +226,12 @@ void Sandbox::Server::_handle_create_session_request(Xml_node request,
 
 		Arg_string::set_arg(argbuf, sizeof(argbuf), "ram_quota", forward_ram_quota.value);
 
+		Session::Diag const diag = session_diag_from_args(args.string());
+
 		Session_state &session =
 			route.service.create_session(route.service.factory(),
-		                                 _client_id_space, id, route.label,
+			                             _client_id_space, id, route.label,
-		                                 argbuf, Affinity::from_xml(request));
+			                             diag, argbuf, Affinity::from_xml(request));
 
 		/* transfer session quota */
 		try {
@@ -401,7 +403,7 @@ void Sandbox::Server::apply_config(Xml_node config)
 			                                             session.client_label());
 
 			bool const route_unchanged = (route.service == session.service())
-			                          && (route.label == session.label());
+			                          && (route.label   == session.label());
 			if (!route_unchanged)
 				throw Service_denied();
 		}

repos/os/src/server/loader/child.h

@@ -126,11 +126,12 @@ class Loader::Child : public Child_policy
 		}
 
 		Route resolve_session_request(Service::Name const &name,
-		                              Session_label const &label) override
+		                              Session_label const &label,
+		                              Session::Diag const  diag) override
 		{
 			return Route { .service = _matching_service(name),
 			               .label   = label,
-			               .diag    = Session::Diag() };
+			               .diag    = diag };
 		}
 };
 

repos/os/src/test/bomb/main.cc

@@ -101,11 +101,12 @@ class Bomb_child : public Child_policy
 		}
 
 		Route resolve_session_request(Service::Name const &service_name,
-		                              Session_label const &label) override
+		                              Session_label const &label,
+		                              Session::Diag const  diag) override
 		{
 			return Route { .service = _matching_service(service_name, label),
 			               .label   = label,
-			               .diag    = Session::Diag() };
+			               .diag    = diag };
 		}
 };
 

repos/os/src/test/fault_detection/main.cc

@@ -120,12 +120,13 @@ class Test_child : public Genode::Child_policy
 		}
 
 		Route resolve_session_request(Service::Name const &service,
-		                              Session_label const &label) override
+		                              Session_label const &label,
+		                              Session::Diag const  diag) override
 		{
 			auto route = [&] (Service &service) {
 				return Route { .service = service,
 				               .label   = label,
-				               .diag    = Session::Diag() }; };
+				               .diag    = diag }; };
 
 			if (service == Cpu_session::service_name()) return route(_cpu_service);
 			if (service ==  Pd_session::service_name()) return route( _pd_service);

repos/ports/src/app/gdb_monitor/app_child.h

@@ -306,11 +306,12 @@ class Gdb_monitor::App_child : public Child_policy,
 		}
 
 		Route resolve_session_request(Service::Name const &service_name,
-		                              Session_label const &label) override
+		                              Session_label const &label,
+		                              Session::Diag const  diag) override
 		{
 			return Route { .service = _matching_service(service_name, label),
 			               .label   = label,
-			               .diag    = Session::Diag() };
+			               .diag    = diag };
 		}
 
 		void announce_service(Service::Name const &service_name) override