Get machine_id working on macOS as well

tools/cmd/mouse_demo/main.go

@@ -10,14 +10,15 @@ import (
 	"encoding/hex"
 	"fmt"
 	"net/url"
-	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
 
-	kitty "github.com/kovidgoyal/kitty"
+	"github.com/kovidgoyal/kitty"
 	"github.com/kovidgoyal/kitty/tools/tty"
 	"github.com/kovidgoyal/kitty/tools/tui/loop"
+	"github.com/kovidgoyal/kitty/tools/utils"
+	"github.com/kovidgoyal/kitty/tools/utils/machine_id"
 )
 
 var _ = fmt.Print
@@ -41,13 +42,12 @@ func dnd_escape(metadata, payload string) string {
 // get_machine_id returns the machine id in the format expected by the DnD
 // protocol ("1:" followed by HMAC-SHA256 of /etc/machine-id).
 func get_machine_id() string {
-	data, err := os.ReadFile("/etc/machine-id")
+	ans, err := machine_id.MachineId()
 	if err != nil {
 		return ""
 	}
-	data = bytes.TrimRight(data, "\n")
 	mac := hmac.New(sha256.New, []byte("tty-dnd-protocol-machine-id"))
-	mac.Write(data)
+	mac.Write(utils.UnsafeStringToBytes(ans))
 	return "1:" + hex.EncodeToString(mac.Sum(nil))
 }
 

tools/utils/machine_id/api.go

@@ -0,0 +1,10 @@
+package machine_id
+
+import (
+	"fmt"
+	"sync"
+)
+
+var _ = fmt.Print
+
+var MachineId = sync.OnceValues(read_machine_id)

tools/utils/machine_id/api_test.go

@@ -0,0 +1,15 @@
+package machine_id
+
+import (
+	"fmt"
+	"testing"
+)
+
+var _ = fmt.Print
+
+func TestMachineId(t *testing.T) {
+	_, err := MachineId()
+	if err != nil {
+		t.Fatal(err)
+	}
+}

tools/utils/machine_id/darwin.go

@@ -0,0 +1,81 @@
+//go:build darwin
+
+package machine_id
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/ebitengine/purego"
+)
+
+var _ = fmt.Print
+
+func read_machine_id() (string, error) {
+	const kIOMainPortDefault uint32 = 0
+	const kCFStringEncodingUTF8 uint32 = 0x08000100
+
+	// 1. Load System Frameworks
+	iokit, err := purego.Dlopen("/System/Library/Frameworks/IOKit.framework/IOKit", purego.RTLD_NOW)
+	if err != nil {
+		return "", err
+	}
+	defer purego.Dlclose(iokit)
+	corefoundation, err := purego.Dlopen("/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation", purego.RTLD_NOW)
+	if err != nil {
+		return "", err
+	}
+	defer purego.Dlclose(corefoundation)
+
+	// 2. Register CoreFoundation Functions
+	var cfStringCreateWithCString func(uintptr, *byte, uint32) uintptr
+	purego.RegisterLibFunc(&cfStringCreateWithCString, corefoundation, "CFStringCreateWithCString")
+
+	var cfStringGetCString func(uintptr, *byte, int64, uint32) bool
+	purego.RegisterLibFunc(&cfStringGetCString, corefoundation, "CFStringGetCString")
+
+	var cfRelease func(uintptr)
+	purego.RegisterLibFunc(&cfRelease, corefoundation, "CFRelease")
+
+	// 3. Register IOKit Functions
+	var ioServiceMatching func(*byte) uintptr
+	purego.RegisterLibFunc(&ioServiceMatching, iokit, "IOServiceMatching")
+
+	var ioServiceGetMatchingService func(uint32, uintptr) uint32
+	purego.RegisterLibFunc(&ioServiceGetMatchingService, iokit, "IOServiceGetMatchingService")
+
+	var ioRegistryEntryCreateCFProperty func(uint32, uintptr, uintptr, uint32) uintptr
+	purego.RegisterLibFunc(&ioRegistryEntryCreateCFProperty, iokit, "IORegistryEntryCreateCFProperty")
+
+	var ioObjectRelease func(uint32)
+	purego.RegisterLibFunc(&ioObjectRelease, iokit, "IOObjectRelease")
+
+	// 4. Retrieve the UUID
+	// Convert Go string to CFStringRef for the property key
+	keyName := "IOPlatformUUID\x00"
+	cfKey := cfStringCreateWithCString(0, &[]byte(keyName)[0], kCFStringEncodingUTF8)
+	defer cfRelease(cfKey)
+
+	// Look up the IOPlatformExpertDevice service
+	className := "IOPlatformExpertDevice\x00"
+	matchingDict := ioServiceMatching(&[]byte(className)[0])
+	service := ioServiceGetMatchingService(kIOMainPortDefault, matchingDict)
+	if service == 0 {
+		return "", fmt.Errorf("failed to find IOPlatformExpertDevice service")
+	}
+	defer ioObjectRelease(service)
+
+	// Get the property from the registry
+	cfValue := ioRegistryEntryCreateCFProperty(service, cfKey, 0, 0)
+	if cfValue == 0 {
+		return "", fmt.Errorf("failed to find IOPlatformUUID property")
+	}
+	defer cfRelease(cfValue)
+
+	// Convert the resulting CFString back to a Go string
+	buf := make([]byte, 128)
+	if cfStringGetCString(cfValue, &buf[0], 128, kCFStringEncodingUTF8) {
+		return strings.TrimRight(string(buf), "\x00"), nil
+	}
+	return "", fmt.Errorf("failed to extract string from CFProperty")
+}

tools/utils/machine_id/unix.go

@@ -0,0 +1,23 @@
+//go:build !darwin
+
+package machine_id
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"unicode"
+
+	"github.com/kovidgoyal/kitty/tools/utils"
+)
+
+var _ = fmt.Print
+
+func read_machine_id() (string, error) {
+	if data, err := os.ReadFile("/etc/machine-id"); err == nil {
+		ans := utils.UnsafeBytesToString(data)
+		return strings.TrimRightFunc(ans, unicode.IsSpace), nil
+	} else {
+		return "", err
+	}
+}