internal/wayland: increase error detail

This includes targeted paths in the returned errors.

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

internal/wayland/conn.go

@@ -36,18 +36,18 @@ func (sc *SecurityContext) Close() error {
 func New(displayPath, bindPath *check.Absolute, appID, instanceID string) (*SecurityContext, error) {
 	// ensure bindPath is available
 	if f, err := os.Create(bindPath.String()); err != nil {
-		return nil, &Error{Cause: RHostCreate, Errno: err}
+		return nil, &Error{RCreate, bindPath.String(), displayPath.String(), err}
 	} else if err = f.Close(); err != nil {
-		return nil, &Error{Cause: RHostCreate, Errno: err}
+		return nil, &Error{RCreate, bindPath.String(), displayPath.String(), err}
 	} else if err = os.Remove(bindPath.String()); err != nil {
-		return nil, &Error{Cause: RHostCreate, Errno: err}
+		return nil, &Error{RCreate, bindPath.String(), displayPath.String(), err}
 	}
 
 	if fd, err := syscall.Socket(syscall.AF_UNIX, syscall.SOCK_STREAM|syscall.SOCK_CLOEXEC, 0); err != nil {
-		return nil, &Error{RHostSocket, err}
+		return nil, &Error{RHostSocket, bindPath.String(), displayPath.String(), err}
 	} else if err = syscall.Connect(fd, &syscall.SockaddrUnix{Name: displayPath.String()}); err != nil {
 		_ = syscall.Close(fd)
-		return nil, &Error{RHostConnect, err}
+		return nil, &Error{RHostConnect, bindPath.String(), displayPath.String(), err}
 	} else {
 		closeFds, bindErr := securityContextBindPipe(fd, bindPath, appID, instanceID)
 		if bindErr != nil {

internal/wayland/wayland-client-helper.h

@@ -16,7 +16,7 @@ typedef enum {
   HAKUREI_WAYLAND_LISTEN,
 
   /* ensure pathname failed, implemented in conn.go */
-  HAKUREI_WAYLAND_HOST_CREAT,
+  HAKUREI_WAYLAND_CREAT,
   /* socket for host server failed, implemented in conn.go */
   HAKUREI_WAYLAND_HOST_SOCKET,
   /* connect for host server failed, implemented in conn.go */

internal/wayland/wayland.go

@@ -38,6 +38,10 @@ type (
 	Error struct {
 		// Where the failure occurred.
 		Cause Res
+		// Attempted pathname socket.
+		Path string
+		// Pathname socket to host server. Omitted for libwayland errors.
+		Host string
 		// Global errno value set during the fault.
 		Errno error
 	}
@@ -69,8 +73,8 @@ const (
 	// RListen is returned if listen failed. The global errno is set.
 	RListen Res = C.HAKUREI_WAYLAND_LISTEN
 
-	// RHostCreate is returned if ensuring pathname availability failed. Returned by [New].
-	RHostCreate Res = C.HAKUREI_WAYLAND_HOST_CREAT
+	// RCreate is returned if ensuring pathname availability failed. Returned by [New].
+	RCreate Res = C.HAKUREI_WAYLAND_CREAT
 	// RHostSocket is returned if socket failed for host server. Returned by [New].
 	RHostSocket Res = C.HAKUREI_WAYLAND_HOST_SOCKET
 	// RHostConnect is returned if connect failed for host server. Returned by [New].
@@ -96,21 +100,25 @@ func (e *Error) Error() string {
 	case RNotAvail:
 		return "compositor does not implement security_context_v1"
 
-	case RSocket, RBind, RListen:
+	case RSocket:
 		if e.Errno == nil {
 			return "socket operation failed"
 		}
-		return e.Errno.Error()
+		return "socket: " + e.Errno.Error()
+	case RBind:
+		return e.withPrefix("cannot bind " + e.Path)
+	case RListen:
+		return e.withPrefix("cannot listen on " + e.Path)
 
-	case RHostCreate:
+	case RCreate:
 		if e.Errno == nil {
 			return "cannot ensure wayland pathname socket"
 		}
 		return e.Errno.Error()
 	case RHostSocket:
-		return e.withPrefix("socket for host wayland server")
+		return e.withPrefix("socket")
 	case RHostConnect:
-		return e.withPrefix("connect to host wayland server")
+		return e.withPrefix("cannot connect to " + e.Host)
 
 	default:
 		return e.withPrefix("impossible outcome") /* not reached */
@@ -142,6 +150,7 @@ func securityContextBind(
 	if e.Cause == RSuccess {
 		return nil
 	}
+	e.Path = socketPath
 	return &e
 }
 

internal/wayland/wayland_test.go

@@ -53,30 +53,43 @@ func TestError(t *testing.T) {
 		{"socket", wayland.Error{
 			Cause: wayland.RSocket,
 			Errno: stub.UniqueError(4),
-		}, "unique error 4 injected by the test suite"},
+		}, "socket: unique error 4 injected by the test suite"},
+
+		{"bind", wayland.Error{
+			Cause: wayland.RBind,
+			Path:  "/hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland",
+			Errno: stub.UniqueError(5),
+		}, "cannot bind /hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland: unique error 5 injected by the test suite"},
+
+		{"listen", wayland.Error{
+			Cause: wayland.RListen,
+			Path:  "/hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland",
+			Errno: stub.UniqueError(6),
+		}, "cannot listen on /hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland: unique error 6 injected by the test suite"},
 
 		{"socket invalid", wayland.Error{
 			Cause: wayland.RSocket,
 		}, "socket operation failed"},
 
-		{"host create", wayland.Error{
-			Cause: wayland.RHostCreate,
+		{"create", wayland.Error{
+			Cause: wayland.RCreate,
 		}, "cannot ensure wayland pathname socket"},
 
-		{"host create path", wayland.Error{
-			Cause: wayland.RHostCreate,
+		{"create path", wayland.Error{
+			Cause: wayland.RCreate,
 			Errno: &os.PathError{Op: "create", Path: "/proc/nonexistent", Err: syscall.EEXIST},
 		}, "create /proc/nonexistent: file exists"},
 
 		{"host socket", wayland.Error{
 			Cause: wayland.RHostSocket,
-			Errno: stub.UniqueError(5),
-		}, "socket for host wayland server: unique error 5 injected by the test suite"},
+			Errno: stub.UniqueError(7),
+		}, "socket: unique error 7 injected by the test suite"},
 
 		{"host connect", wayland.Error{
 			Cause: wayland.RHostConnect,
-			Errno: stub.UniqueError(6),
-		}, "connect to host wayland server: unique error 6 injected by the test suite"},
+			Host:  "/run/user/1971/wayland-1",
+			Errno: stub.UniqueError(8),
+		}, "cannot connect to /run/user/1971/wayland-1: unique error 8 injected by the test suite"},
 
 		{"invalid", wayland.Error{
 			Cause: 0xbad,
@@ -84,8 +97,8 @@ func TestError(t *testing.T) {
 
 		{"invalid errno", wayland.Error{
 			Cause: 0xbad,
-			Errno: stub.UniqueError(5),
-		}, "impossible outcome: unique error 5 injected by the test suite"},
+			Errno: stub.UniqueError(9),
+		}, "impossible outcome: unique error 9 injected by the test suite"},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {