更新：修复 junction 入口下的自更新和恢复

internal/update/images_windows.go

@@ -68,7 +68,7 @@ func (u *Updater) lockSDKImages() (release func(), err error) {
 		} else if err != nil {
 			return nil, swapBlocked("无法检查模拟器目录 %s（%v），什么都没动", dir, err)
 		}
-		resolved, err := filepath.EvalSymlinks(dir)
+		resolved, err := resolvePath(dir)
 		if err != nil {
 			return nil, swapBlocked("无法确认模拟器目录 %s（%v），什么都没动", dir, err)
 		}

internal/update/path_identity_windows_test.go

@@ -0,0 +1,323 @@
+//go:build windows
+
+// Copyright 2026 jinghero
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+package update
+
+import (
+	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"syscall"
+	"testing"
+	"time"
+
+	"modavd/internal/jsonord"
+	"modavd/internal/root"
+	"modavd/internal/testutil"
+	"modavd/internal/win"
+)
+
+func updatePathAlias(t *testing.T, target, kind string) string {
+	t.Helper()
+	if kind == "short name" {
+		ptr, err := syscall.UTF16PtrFromString(target)
+		if err != nil {
+			t.Fatal(err)
+		}
+		var buf [32768]uint16
+		n, err := syscall.GetShortPathName(ptr, &buf[0], uint32(len(buf)))
+		if err != nil || n == 0 || n >= uint32(len(buf)) {
+			t.Fatalf("GetShortPathName: %d, %v", n, err)
+		}
+		alias := syscall.UTF16ToString(buf[:n])
+		if strings.EqualFold(alias, target) {
+			t.Skip("test volume does not create 8.3 names")
+		}
+		return alias
+	}
+	alias := filepath.Join(testutil.TempDir(t), "alias")
+	if kind == "symlink" {
+		if err := os.Symlink(target, alias); err != nil {
+			t.Skipf("directory symlink unavailable: %v", err)
+		}
+	} else {
+		cmd := exec.Command("cmd.exe", "/d", "/c", "mklink", "/J", alias, target)
+		cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("mklink /J: %v\n%s", err, out)
+		}
+	}
+	st, err := os.Stat(alias)
+	if err != nil || !st.IsDir() {
+		t.Fatalf("invalid directory alias: %v", err)
+	}
+	return alias
+}
+
+func TestSelfUpdatePathAliases(t *testing.T) {
+	self, err := os.Executable()
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, kind := range []string{"junction", "symlink", "short name"} {
+		for _, reverse := range []bool{false, true} {
+			for _, action := range []string{"check", "apply", "restore", "recover finish", "recover rollback"} {
+				name := kind + "/alias root/" + action
+				if reverse {
+					name = kind + "/alias image/" + action
+				}
+				t.Run(name, func(t *testing.T) {
+					real := filepath.Join(testutil.TempDir(t), "root with long name")
+					if err := copyFile(self, filepath.Join(real, "tools", "modavd.exe")); err != nil {
+						t.Fatal(err)
+					}
+					alias := updatePathAlias(t, real, kind)
+					rootPath, imageRoot := alias, real
+					if reverse {
+						rootPath, imageRoot = real, alias
+					}
+					ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
+					defer cancel()
+					cmd := exec.CommandContext(ctx, filepath.Join(imageRoot, "tools", "modavd.exe"), "-test.run=^TestSelfUpdatePathAliasChild$", "-test.v")
+					cmd.Env = append(os.Environ(), "MODAVD_PATH_ALIAS_ROOT="+rootPath, "MODAVD_PATH_ALIAS_ACTION="+action)
+					cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
+					if out, err := cmd.CombinedOutput(); err != nil {
+						t.Fatalf("self update: %v\n%s", err, out)
+					}
+				})
+			}
+		}
+	}
+}
+
+func TestSelfUpdatePathAliasChild(t *testing.T) {
+	dir := os.Getenv("MODAVD_PATH_ALIAS_ROOT")
+	if dir == "" {
+		t.Skip("self-update fixture only")
+	}
+	l := layout{root: dir}
+	const rel = "tools/modavd.exe"
+	plan := rootPlan{replace: []string{rel}}
+	action := os.Getenv("MODAVD_PATH_ALIAS_ACTION")
+	if action == "check" {
+		if busy := l.rootFileInUse(plan); busy != "" {
+			t.Fatalf("self treated as occupant: %s", busy)
+		}
+		self, err := os.Executable()
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := copyFile(self, l.at("ModAVD.exe")); err != nil {
+			t.Fatal(err)
+		}
+		occupancyChild(t, l.at("ModAVD.exe"))
+		plan.replace = append(plan.replace, "ModAVD.exe")
+		if busy := l.rootFileInUse(plan); busy != "ModAVD.exe" {
+			t.Fatalf("different running image was exempted: %q", busy)
+		}
+		return
+	}
+	source := l.pkgAt(rel)
+	if action == "restore" || action == "recover rollback" {
+		source = l.prevAt(rel)
+	}
+	write := func(path, body string) {
+		t.Helper()
+		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
+			t.Fatal(err)
+		}
+	}
+	write(source, action)
+	var err error
+	switch action {
+	case "apply":
+		err = l.applyRootFiles(plan)
+	case "restore":
+		err = l.restoreRootFiles(plan)
+	case "recover finish", "recover rollback":
+		write(l.at("mas-avd.json"), "{}")
+		if err := os.MkdirAll(l.at("sdk"), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		st := newState(phaseSwapping, "plan", plan.value(), "swap", stepVal(stepOldMoved))
+		target := jsonord.NewObject()
+		target.Obj().Set("version", jsonord.NewString("v0.37.0"))
+		st.Set("target", target)
+		if action == "recover finish" {
+			write(filepath.Join(l.stageEmulator(), "marker"), "new SDK")
+			staged := jsonord.NewObject()
+			staged.Obj().Set("verified", jsonord.NewBool(true))
+			st.Set("staged", staged)
+		} else {
+			write(filepath.Join(l.previousEmulator(), "marker"), "old SDK")
+		}
+		if err := l.writeState(st); err != nil {
+			t.Fatal(err)
+		}
+		r, err := root.New(dir)
+		if err != nil {
+			t.Fatal(err)
+		}
+		u := New(r, nil, Options{})
+		u.scan = ownScan(u)
+		if _, err := u.recover(); err != nil {
+			t.Fatal(err)
+		}
+		if phaseOf(l.readState()) != phaseIdle || !isDir(l.emulator()) {
+			t.Fatal("recovery did not commit its result")
+		}
+		wantSDK := "old SDK"
+		if action == "recover finish" {
+			wantSDK = "new SDK"
+		}
+		if got, err := os.ReadFile(filepath.Join(l.emulator(), "marker")); err != nil || string(got) != wantSDK {
+			t.Fatalf("wrong recovered SDK: %q, %v", got, err)
+		}
+		ok, _ := l.readState().Get("lastResult").Obj().Get("ok").BoolVal()
+		if ok != (action == "recover finish") {
+			t.Fatalf("wrong recovery result: ok=%v", ok)
+		}
+	default:
+		t.Fatalf("unknown action: %s", action)
+	}
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got, err := os.ReadFile(l.at(rel)); err != nil || string(got) != action {
+		t.Fatalf("wrong replacement: %q, %v", got, err)
+	}
+}
+
+func TestPathAliasProcessOwnership(t *testing.T) {
+	for _, kind := range []string{"junction", "symlink", "short name"} {
+		for _, reverse := range []bool{false, true} {
+			for _, rel := range []string{"tools/modavd.exe", "ModAVD.exe", "sdk/emulator/emulator.exe", ".update/previous/emulator/emulator.exe"} {
+				name := kind + "/alias root/" + rel
+				if reverse {
+					name = kind + "/alias image/" + rel
+				}
+				t.Run(name, func(t *testing.T) {
+					r := writeRoot(t, 36, nil)
+					self, err := os.Executable()
+					if err != nil {
+						t.Fatal(err)
+					}
+					if err := copyFile(self, filepath.Join(r.Dir, filepath.FromSlash(rel))); err != nil {
+						t.Fatal(err)
+					}
+					alias := updatePathAlias(t, r.Dir, kind)
+					rootPath, imageRoot := alias, r.Dir
+					if reverse {
+						rootPath, imageRoot = r.Dir, alias
+					}
+					u := New(&root.Root{Dir: rootPath}, nil, Options{})
+					if err := u.l.writeState(newState(phaseSwapping)); err != nil {
+						t.Fatal(err)
+					}
+					child := occupancyChild(t, filepath.Join(imageRoot, filepath.FromSlash(rel)))
+					program := rel == "tools/modavd.exe" || rel == "ModAVD.exe"
+					for _, programs := range []bool{false, true} {
+						uses, err := u.scanProcesses(programs, ownProcesses, win.Process.ImagePath)
+						if err != nil {
+							t.Fatal(err)
+						}
+						want := !program || programs
+						if !want {
+							if len(uses) != 0 {
+								t.Fatalf("program scan disabled: %+v", uses)
+							}
+							continue
+						}
+						if len(uses) != 1 || uses[0].PID != uint32(child.Process.Pid) || uses[0].RootProgram != program || uses[0].ShutdownHelper {
+							t.Fatalf("wrong process ownership: %+v", uses)
+						}
+					}
+					if program {
+						image := filepath.Join(imageRoot, filepath.FromSlash(rel))
+						if !u.shutdownHelper(image, []string{image, "__bootwatch", imageRoot, "0", "123", "456"}) {
+							t.Error("same root's bootwatch was not recognized")
+						}
+						if u.shutdownHelper(image, []string{image, "__bootwatch", t.TempDir(), "0", "123", "456"}) {
+							t.Error("another root's bootwatch was recognized")
+						}
+					}
+				})
+			}
+		}
+	}
+}
+
+func TestPathAliasSDKInstall(t *testing.T) {
+	u, _ := imageUpdate(t)
+	alias := updatePathAlias(t, u.Root.Dir, "junction")
+	u.Root = &root.Root{Dir: alias}
+	u.l.root = alias
+	u.scan = ownScan(u)
+	if st, err := u.Install(context.Background()); err != nil || !st.Updated || st.Phase != phaseIdle {
+		t.Fatalf("install through junction: %+v, %v", st, err)
+	}
+}
+
+func TestPathAliasReadOnlyLoadedImage(t *testing.T) {
+	dir := testutil.TempDir(t)
+	alias := updatePathAlias(t, dir, "junction")
+	path := filepath.Join(dir, "loaded.dll")
+	free := loadDLL(t, filepath.Join(alias, "loaded.dll"))
+	if err := os.Chmod(path, 0o444); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { os.Chmod(path, 0o666) })
+	for _, probe := range []string{path, filepath.Join(alias, "loaded.dll")} {
+		if !loadedImageInUse(probe) {
+			t.Error("loaded image query missed through junction")
+		}
+		if !fileInUse(probe) {
+			t.Error("read-only loaded image missed through junction")
+		}
+	}
+	free()
+	if fileInUse(path) {
+		t.Error("unloaded read-only image is still busy")
+	}
+}
+
+func TestPathAliasDifferentRoot(t *testing.T) {
+	r := writeRoot(t, 36, nil)
+	alias := updatePathAlias(t, r.Dir, "junction")
+	u := New(&root.Root{Dir: alias}, nil, Options{})
+	other := filepath.Join(testutil.TempDir(t), "tools", "modavd.exe")
+	self, err := os.Executable()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := copyFile(self, other); err != nil {
+		t.Fatal(err)
+	}
+	occupancyChild(t, other)
+	if uses, err := u.scanProcesses(true, ownProcesses, win.Process.ImagePath); err != nil || len(uses) != 0 {
+		t.Fatalf("another root's program matched: %+v, %v", uses, err)
+	}
+	if u.shutdownHelper(other, []string{other, "__bootwatch", alias, "0", "123", "456"}) {
+		t.Fatal("another root's program was treated as a shutdown helper")
+	}
+}
+
+func TestUpdatePathResolutionFailure(t *testing.T) {
+	missing := filepath.Join(t.TempDir(), "missing")
+	if _, err := resolvePath(missing); err == nil {
+		t.Fatal("missing path resolved successfully")
+	}
+	if got := realOrSame(missing); got != missing {
+		t.Fatalf("missing path fallback changed: %q", got)
+	}
+	if _, err := resolvePath("invalid\x00path"); err == nil {
+		t.Fatal("invalid path resolved successfully")
+	}
+}

internal/update/state_other.go

@@ -2,10 +2,15 @@
 
 package update
 
-import "os"
+import (
+	"os"
+	"path/filepath"
+)
 
 func isReparsePoint(st os.FileInfo) bool { return st.Mode()&os.ModeSymlink != 0 }
 func removeLink(p string) bool           { return os.Remove(p) == nil }
 
 // fileInUse: a loaded library or an open file never stops a rename or an unlink here.
 func fileInUse(string) bool { return false }
+
+func resolvePath(path string) (string, error) { return filepath.EvalSymlinks(path) }

internal/update/state_windows.go

@@ -77,25 +77,38 @@ func loadedImageInUse(path string) bool {
 	return false
 }
 
+// resolvePath returns an extended DOS path suitable for both comparisons and I/O.
+// Handle queries resolve junctions and short names without EvalSymlinks.
+func resolvePath(path string) (string, error) {
+	return finalPath(path, 0)
+}
+
 func finalImagePath(path string) string {
+	const volumeNameNT = 2
+	name, _ := finalPath(path, volumeNameNT)
+	return name
+}
+
+func finalPath(path string, flags uint32) (string, error) {
 	ptr, err := syscall.UTF16PtrFromString(path)
 	if err != nil {
-		return ""
+		return "", err
 	}
 	h, err := syscall.CreateFile(ptr, 0, syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
-		nil, syscall.OPEN_EXISTING, 0, 0)
+		nil, syscall.OPEN_EXISTING, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
 	if err != nil {
-		return ""
+		return "", err
 	}
 	var name [32768]uint16
-	const volumeNameNT = 2
-	n, _, _ := getFinalPathNameW.Call(uintptr(h), uintptr(unsafe.Pointer(&name[0])), uintptr(len(name)), volumeNameNT)
+	n, _, err := getFinalPathNameW.Call(uintptr(h), uintptr(unsafe.Pointer(&name[0])), uintptr(len(name)), uintptr(flags))
 	syscall.CloseHandle(h)
-	if n == 0 || n >= uintptr(len(name)) {
-		return ""
+	if n == 0 {
+		return "", err
+	}
+	if n >= uintptr(len(name)) {
+		return "", syscall.ERROR_INSUFFICIENT_BUFFER
 	}
-	// Resolve directory links and 8.3 names into the same NT device path.
-	return syscall.UTF16ToString(name[:n])
+	return syscall.UTF16ToString(name[:n]), nil
 }
 
 func processHasImage(pid uint32, target string) bool {