Reset X11 button state on reconnect, read the Shift+AltGr console table, sync remote Caps Lock with macOS, and restore the FreeBSD stride test

client/vnc/server/capture_fb_freebsd_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // fb_depth is colour depth, not storage: a KMS console is depth 24 stored as
@@ -32,3 +33,33 @@ func TestFreebsdStorageBits(t *testing.T) {
 		})
 	}
 }
+
+// The row pitch is derived from the mapping, not computed from width and
+// depth: a KMS framebuffer pads its rows, and reading at the unpadded width
+// shears the image. A mapping too small for the reported geometry would have
+// rows read off its end, so it is refused rather than guessed at.
+func TestFreebsdFBStride(t *testing.T) {
+	tests := []struct {
+		name    string
+		fbt     fbType
+		want    int
+		wantErr bool
+	}{
+		{"unpadded 32-bit", fbType{FbWidth: 1024, FbHeight: 768, FbDepth: 32, FbSize: 1024 * 768 * 4}, 4096, false},
+		{"padded rows", fbType{FbWidth: 1000, FbHeight: 768, FbDepth: 32, FbSize: 4096 * 768}, 4096, false},
+		{"packed 24-bit", fbType{FbWidth: 1024, FbHeight: 768, FbDepth: 24, FbSize: 1024 * 768 * 3}, 3072, false},
+		{"16-bit", fbType{FbWidth: 800, FbHeight: 600, FbDepth: 16, FbSize: 800 * 600 * 2}, 1600, false},
+		{"size cannot hold the geometry", fbType{FbWidth: 1024, FbHeight: 768, FbDepth: 32, FbSize: 1024 * 768 * 2}, 0, true},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got, err := freebsdFBStride(tc.fbt)
+			if tc.wantErr {
+				require.Error(t, err, "a mapping smaller than the geometry must be refused")
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, tc.want, got, "row pitch in bytes")
+		})
+	}
+}

client/vnc/server/input_darwin.go

@@ -97,6 +97,9 @@ var (
 	// event, so the receiving app gets those characters whatever the active
 	// keyboard layout would have produced for the keycode.
 	cgEventKeyboardSetUnicodeString func(uintptr, uintptr, *uint16)
+	// cgEventSourceFlagsState reads the modifier flags macOS currently holds
+	// for an event-source state, which is where the real Caps Lock state is.
+	cgEventSourceFlagsState func(int32) uint64
 
 	// CGEventCreateScrollWheelEvent is variadic, call via SyscallN.
 	cgEventCreateScrollWheelEventAddr uintptr
@@ -171,6 +174,9 @@ func initDarwinInput() {
 		if sym, err := purego.Dlsym(cg, "CGEventKeyboardSetUnicodeString"); err == nil {
 			purego.RegisterFunc(&cgEventKeyboardSetUnicodeString, sym)
 		}
+		if sym, err := purego.Dlsym(cg, "CGEventSourceFlagsState"); err == nil {
+			purego.RegisterFunc(&cgEventSourceFlagsState, sym)
+		}
 
 		sym, err := purego.Dlsym(cg, "CGEventCreateScrollWheelEvent")
 		if err == nil {
@@ -616,13 +622,22 @@ func (m *MacInputInjector) postModifier(src uintptr, keycode uint16, down bool,
 	if capsLock && !down {
 		return
 	}
+	// Toggle from the state macOS actually has, not from the one this injector
+	// has built up: Caps Lock may already be on when the injector starts, or be
+	// toggled at the local keyboard in the meantime, and toggling a stale copy
+	// would post the state the system is already in instead of a transition.
+	systemCaps, haveSystemCaps := systemCapsLock()
 
 	var flags uint64
 	for {
 		old := m.modifiers.Load()
 		switch {
 		case capsLock:
-			flags = old ^ bit
+			current := old & bit
+			if haveSystemCaps {
+				current = systemCaps
+			}
+			flags = (old &^ bit) | (current ^ bit)
 		case down:
 			flags = old | bit
 		default:
@@ -893,8 +908,11 @@ func (m *MacInputInjector) SetClipboard(text string) {
 // TypeText synthesizes the given text as keystrokes via Core Graphics.
 // Lets a client push host clipboard content to the focused remote app
 // even when the app doesn't honor pbpaste-style clipboard sync (e.g.
-// login screens, locked-down apps). ASCII printable runes only; others
-// are skipped.
+// login screens, locked-down apps). Printable runes, non-ASCII included, are
+// attached to the events as literal text, so they arrive as written whatever
+// the host's keyboard layout. Return and Tab go out as their keys. Where the
+// literal-text call is unavailable, ASCII falls back to US-layout keycodes and
+// anything else is skipped.
 func (m *MacInputInjector) TypeText(text string) {
 	// Same permission the other injection paths need: without it the posted
 	// events are swallowed, so asking here is what makes the prompt appear
@@ -1149,3 +1167,12 @@ func (m *MacInputInjector) typeUnicodeRune(src uintptr, r rune) bool {
 	}
 	return true
 }
+
+// systemCapsLock returns the Caps Lock bit macOS currently holds, and false
+// when that cannot be read.
+func systemCapsLock() (uint64, bool) {
+	if cgEventSourceFlagsState == nil {
+		return 0, false
+	}
+	return cgEventSourceFlagsState(kCGEventSourceStateCombinedSessionState) & kCGEventFlagMaskAlphaShift, true
+}

client/vnc/server/input_uinput_keymap_linux.go

@@ -17,12 +17,14 @@ const consoleTTY = "/dev/tty0"
 // kdgkbent is KDGKBENT from linux/kd.h, which reads one keymap entry.
 const kdgkbent = 0x4B46
 
-// Keymap tables (linux/keyboard.h): the character a key produces unmodified,
-// with Shift, and with AltGr.
+// Keymap tables (linux/keyboard.h), indexed by the modifier bits held: the
+// character a key produces unmodified, with Shift (KG_SHIFT), with AltGr
+// (KG_ALTGR), and with both.
 const (
-	kNormTab  = 0
-	kShiftTab = 1
-	kAltGrTab = 2
+	kNormTab       = 0
+	kShiftTab      = 1
+	kAltGrTab      = 2
+	kShiftAltGrTab = 3
 )
 
 // Key types (linux/keyboard.h). KT_LATIN and KT_LETTER carry a Latin-1
@@ -50,9 +52,10 @@ type consoleKey struct {
 }
 
 // readConsoleKeymap reads the active console keymap and returns, for every
-// printable character it can type, the key that types it. The unmodified table
-// wins over the Shift one, and both over AltGr, so a character reachable more
-// than one way gets the simplest.
+// printable character it can type, the key that types it. Tables are read from
+// fewest modifiers to most (plain, Shift, AltGr, Shift+AltGr), and the first
+// one to produce a character wins, so a character reachable more than one way
+// gets the simplest.
 //
 // The kernel decodes uinput key codes with this same keymap, which is what makes
 // it the right source. A fixed US table types the wrong characters on any other
@@ -71,6 +74,7 @@ func readConsoleKeymap(tty string) (map[rune]consoleKey, error) {
 		{kNormTab, consoleKey{}},
 		{kShiftTab, consoleKey{shift: true}},
 		{kAltGrTab, consoleKey{altGr: true}},
+		{kShiftAltGrTab, consoleKey{shift: true, altGr: true}},
 	}
 
 	out := make(map[rune]consoleKey)

client/vnc/server/input_x11.go

@@ -132,6 +132,10 @@ func (x *X11InputInjector) ensureConnLocked() {
 	x.conn = conn
 	x.root = screen.Root
 	x.screen = &screen
+	// The new server has no buttons down. Keeping the old mask would make a
+	// button still held across the restart look already pressed, so it would
+	// never get the ButtonPress it now needs.
+	x.lastButtons = 0
 	x.cacheKeyboardMapping()
 	log.Infof("X11 input injector reconnected (display=%s)", x.display)
 }