internal/app: copy parts of config to state

This is less error-prone than passing the address to the entire hst.Config struct, and reduces the likelihood of accidentally clobbering hst.Config. This also improves ease of testing.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/app/app_test.go

@@ -464,7 +464,7 @@ func TestApp(t *testing.T) {
 				}
 
 				gotSys = system.New(t.Context(), msg, sPriv.uid.unwrap())
-				if err := (&outcomeStateSys{config: tc.config, sys: gotSys, outcomeState: &sPriv}).toSystem(); err != nil {
+				if err := sPriv.newSys(tc.config, gotSys).toSystem(); err != nil {
 					t.Fatalf("toSystem: error = %#v", err)
 				}
 

internal/app/finalise.go

@@ -81,7 +81,7 @@ func (k *outcome) finalise(ctx context.Context, msg message.Msg, id *state.ID, c
 	}
 
 	sys := system.New(k.ctx, msg, s.uid.unwrap())
-	if err := (&outcomeStateSys{config: config, sys: sys, outcomeState: &s}).toSystem(); err != nil {
+	if err := s.newSys(config, sys).toSystem(); err != nil {
 		return err
 	}
 

internal/app/outcome.go

@@ -134,7 +134,7 @@ func (s *outcomeState) instancePath() *check.Absolute { return s.sc.SharePath.Ap
 func (s *outcomeState) runtimePath() *check.Absolute { return s.sc.RunDirPath.Append(s.id.String()) }
 
 // outcomeStateSys wraps outcomeState and [system.I]. Used on the priv side only.
-// Implementations of outcomeOp must not access fields other than sys and config unless explicitly stated.
+// Implementations of outcomeOp must not access fields other than sys unless explicitly stated.
 type outcomeStateSys struct {
 	// Whether XDG_RUNTIME_DIR is used post hsu.
 	useRuntimeDir bool
@@ -142,13 +142,33 @@ type outcomeStateSys struct {
 	sharePath *check.Absolute
 	// Process-specific directory in XDG_RUNTIME_DIR, nil if unused.
 	runtimeSharePath *check.Absolute
-	// Must not be modified by outcomeOp.
-	config *hst.Config
+
+	// Copied from [hst.Config]. Safe for read by outcomeOp.toSystem.
+	appId string
+	// Copied from [hst.Config]. Safe for read by outcomeOp.toSystem.
+	et hst.Enablement
+
+	// Copied from [hst.Config]. Safe for read by spWaylandOp.toSystem only.
+	directWayland bool
+	// Copied header from [hst.Config]. Safe for read by spFinalOp.toSystem only.
+	extraPerms []*hst.ExtraPermConfig
+	// Copied address from [hst.Config. Safe for read by spDBusOp.toSystem only.
+	sessionBus, systemBus *hst.BusConfig
 
 	sys *system.I
 	*outcomeState
 }
 
+// outcomeState returns the address of a new outcomeStateSys embedding the current outcomeState.
+func (s *outcomeState) newSys(config *hst.Config, sys *system.I) *outcomeStateSys {
+	return &outcomeStateSys{
+		appId: config.ID, et: config.Enablements.Unwrap(),
+		directWayland: config.DirectWayland, extraPerms: config.ExtraPerms,
+		sessionBus: config.SessionBus, systemBus: config.SystemBus,
+		sys: sys, outcomeState: s,
+	}
+}
+
 // ensureRuntimeDir must be called if access to paths within XDG_RUNTIME_DIR is required.
 func (state *outcomeStateSys) ensureRuntimeDir() {
 	if state.useRuntimeDir {
@@ -245,7 +265,7 @@ func (state *outcomeStateSys) toSystem() error {
 		&spPulseOp{},
 		&spDBusOp{},
 
-		spFinal{},
+		spFinalOp{},
 	}
 
 	state.Shim.Ops = make([]outcomeOp, 0, len(ops))

internal/app/spdbus.go

@@ -19,26 +19,26 @@ type spDBusOp struct {
 }
 
 func (s *spDBusOp) toSystem(state *outcomeStateSys) error {
-	if state.config.Enablements.Unwrap()&hst.EDBus == 0 {
+	if state.et&hst.EDBus == 0 {
 		return errNotEnabled
 	}
 
-	if state.config.SessionBus == nil {
-		state.config.SessionBus = dbus.NewConfig(state.config.ID, true, true)
+	if state.sessionBus == nil {
+		state.sessionBus = dbus.NewConfig(state.appId, true, true)
 	}
 
 	// downstream socket paths
 	sessionPath, systemPath := state.instance().Append("bus"), state.instance().Append("system_bus_socket")
 
 	if err := state.sys.ProxyDBus(
-		state.config.SessionBus, state.config.SystemBus,
+		state.sessionBus, state.systemBus,
 		sessionPath, systemPath,
 	); err != nil {
 		return err
 	}
 
 	state.sys.UpdatePerm(sessionPath, acl.Read, acl.Write)
-	if state.config.SystemBus != nil {
+	if state.systemBus != nil {
 		s.ProxySystem = true
 		state.sys.UpdatePerm(systemPath, acl.Read, acl.Write)
 	}

internal/app/spfinal.go

@@ -13,15 +13,15 @@ import (
 	"hakurei.app/system/acl"
 )
 
-func init() { gob.Register(spFinal{}) }
+func init() { gob.Register(spFinalOp{}) }
 
-// spFinal is a transitional op destined for removal after #3, #8, #9 has been resolved.
+// spFinalOp is a transitional op destined for removal after #3, #8, #9 has been resolved.
 // It exists to avoid reordering the expected entries in test cases.
-type spFinal struct{}
+type spFinalOp struct{}
 
-func (s spFinal) toSystem(state *outcomeStateSys) error {
+func (s spFinalOp) toSystem(state *outcomeStateSys) error {
 	// append ExtraPerms last
-	for _, p := range state.config.ExtraPerms {
+	for _, p := range state.extraPerms {
 		if p == nil || p.Path == nil {
 			continue
 		}
@@ -45,7 +45,7 @@ func (s spFinal) toSystem(state *outcomeStateSys) error {
 	return nil
 }
 
-func (s spFinal) toContainer(state *outcomeStateParams) error {
+func (s spFinalOp) toContainer(state *outcomeStateParams) error {
 	// TODO(ophestra): move this to spFilesystemOp after #8 and #9
 
 	// mount root read-only as the final setup Op

internal/app/sppulse.go

@@ -24,7 +24,7 @@ type spPulseOp struct {
 }
 
 func (s *spPulseOp) toSystem(state *outcomeStateSys) error {
-	if state.config.Enablements.Unwrap()&hst.EPulse == 0 {
+	if state.et&hst.EPulse == 0 {
 		return errNotEnabled
 	}
 

internal/app/spwayland.go

@@ -18,7 +18,7 @@ type spWaylandOp struct {
 }
 
 func (s *spWaylandOp) toSystem(state *outcomeStateSys) error {
-	if state.config.Enablements.Unwrap()&hst.EWayland == 0 {
+	if state.et&hst.EWayland == 0 {
 		return errNotEnabled
 	}
 
@@ -33,14 +33,14 @@ func (s *spWaylandOp) toSystem(state *outcomeStateSys) error {
 		socketPath = a
 	}
 
-	if !state.config.DirectWayland { // set up security-context-v1
-		appID := state.config.ID
-		if appID == "" {
+	if !state.directWayland { // set up security-context-v1
+		appId := state.appId
+		if appId == "" {
 			// use instance ID in case app id is not set
-			appID = "app.hakurei." + state.id.String()
+			appId = "app.hakurei." + state.id.String()
 		}
 		// downstream socket paths
-		state.sys.Wayland(state.instance().Append("wayland"), socketPath, appID, state.id.String())
+		state.sys.Wayland(state.instance().Append("wayland"), socketPath, appId, state.id.String())
 	} else { // bind mount wayland socket (insecure)
 		state.msg.Verbose("direct wayland access, PROCEED WITH CAUTION")
 		state.ensureRuntimeDir()

internal/app/spx11.go

@@ -25,7 +25,7 @@ type spX11Op struct {
 }
 
 func (s *spX11Op) toSystem(state *outcomeStateSys) error {
-	if state.config.Enablements.Unwrap()&hst.EX11 == 0 {
+	if state.et&hst.EX11 == 0 {
 		return errNotEnabled
 	}