app: move wayland mediation to shim package

Values used in the Wayland mediation implementation is stored in various struct fields strewn across multiple app structs and checks are messy and confusing. This commit unifies them into a single struct and access it using much better looking methods.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

internal/shim/parent.go

@@ -14,19 +14,18 @@ import (
 
 // called in the parent process
 
-func ServeConfig(socket string, uid int, payload *Payload, wl string, done chan struct{}) (*net.UnixConn, error) {
-	var ws *net.UnixConn
+func ServeConfig(socket string, uid int, payload *Payload, wl *Wayland) error {
 	if payload.WL {
-		if f, err := net.DialUnix("unix", nil, &net.UnixAddr{Name: wl, Net: "unix"}); err != nil {
-			return nil, err
+		if f, err := net.DialUnix("unix", nil, &net.UnixAddr{Name: wl.Path, Net: "unix"}); err != nil {
+			return err
 		} else {
 			verbose.Println("connected to wayland at", wl)
-			ws = f
+			wl.UnixConn = f
 		}
 	}
 
 	if c, err := net.ListenUnix("unix", &net.UnixAddr{Name: socket, Net: "unix"}); err != nil {
-		return nil, err
+		return err
 	} else {
 		verbose.Println("configuring shim on socket", socket)
 		if err = acl.UpdatePerm(socket, uid, acl.Read, acl.Write, acl.Execute); err != nil {
@@ -47,7 +46,7 @@ func ServeConfig(socket string, uid int, payload *Payload, wl string, done chan
 				if payload.WL {
 					// get raw connection
 					var rc syscall.RawConn
-					if rc, err = ws.SyscallConn(); err != nil {
+					if rc, err = wl.SyscallConn(); err != nil {
 						fmt.Println("fortify: cannot obtain raw wayland connection:", err)
 						return
 					} else {
@@ -61,7 +60,7 @@ func ServeConfig(socket string, uid int, payload *Payload, wl string, done chan
 								_ = conn.Close()
 
 								// block until shim exits
-								<-done
+								<-wl.done
 								verbose.Println("releasing wayland connection")
 							}); err != nil {
 								fmt.Println("fortify: cannot obtain wayland connection fd:", err)
@@ -79,6 +78,6 @@ func ServeConfig(socket string, uid int, payload *Payload, wl string, done chan
 				fmt.Println("fortify: cannot remove dangling shim socket:", err)
 			}
 		}()
-		return ws, nil
+		return nil
 	}
 }

internal/shim/wayland.go

@@ -0,0 +1,35 @@
+package shim
+
+import (
+	"net"
+	"sync"
+)
+
+// Wayland implements wayland mediation.
+type Wayland struct {
+	// wayland socket path
+	Path string
+
+	// wayland connection
+	*net.UnixConn
+
+	connErr error
+	sync.Once
+	// wait for wayland client to exit
+	done chan struct{}
+}
+
+func (wl *Wayland) Close() error {
+	wl.Do(func() {
+		close(wl.done)
+		wl.connErr = wl.UnixConn.Close()
+	})
+
+	return wl.connErr
+}
+
+func NewWayland() *Wayland {
+	wl := new(Wayland)
+	wl.done = make(chan struct{})
+	return wl
+}