Platform: Consolidate regular file resolution

Reuse ResolveRegularFile for Lua loading/signing, local config, and assets.
Only evaluate file symlinks when needed, tolerating junction-related
resolution failures on a best-effort basis.

common/platform/filesystem/file.go

@@ -61,15 +61,7 @@ func getAssetFileLocation(file string) (string, os.FileInfo, error) {
 	if err != nil {
 		return "", nil, err
 	}
-	path := platform.GetAssetLocation(local)
-	info, err := os.Stat(path)
-	if err != nil {
-		return "", nil, err
-	}
-	if !info.Mode().IsRegular() {
-		return "", nil, errors.New("asset is not a regular file")
-	}
-	return path, info, nil
+	return platform.ResolveRegularFile(platform.GetAssetLocation(local))
 }
 
 func ReadCert(file string) ([]byte, error) {

common/platform/platform.go

@@ -96,9 +96,6 @@ func GetConfDirPath() string {
 // ResolveLuaFile finds a local .lua script and returns its resolved absolute path.
 // Relative paths: XRAY_LOCATION_CONFDIR > XRAY_LOCATION_CONFIG > working dir > executable dir.
 func ResolveLuaFile(path string) (string, error) {
-	if path == "" {
-		return "", errors.New("Lua file path is empty")
-	}
 	paths := []string{path}
 	if !filepath.IsAbs(path) {
 		paths = nil
@@ -117,14 +114,6 @@ func ResolveLuaFile(path string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return resolveLuaTarget(path)
-}
-
-func resolveLuaTarget(path string) (string, error) {
-	path, err := filepath.EvalSymlinks(path)
-	if err != nil {
-		return "", fmt.Errorf("failed to resolve Lua file symlinks: %w", err)
-	}
 	if filepath.Ext(path) != ".lua" {
 		return "", errors.New("Lua file extension must be .lua")
 	}
@@ -134,22 +123,43 @@ func resolveLuaTarget(path string) (string, error) {
 func resolveFile(paths []string) (string, error) {
 	var tried []string
 	for _, path := range paths {
-		path, err := filepath.Abs(path)
-		if err != nil {
-			return "", fmt.Errorf("failed to resolve file path: %w", err)
-		}
 		tried = append(tried, path)
-		info, err := os.Stat(path)
+		path, _, err := ResolveRegularFile(path)
 		if errors.Is(err, os.ErrNotExist) {
 			continue
 		}
 		if err != nil {
-			return "", fmt.Errorf("failed to inspect file %q: %w", path, err)
-		}
-		if !info.Mode().IsRegular() {
-			return "", fmt.Errorf("file is not a regular file: %s", path)
+			return "", err
 		}
 		return path, nil
 	}
 	return "", fmt.Errorf("file not found; tried %q: %w", tried, os.ErrNotExist)
 }
+
+// ResolveRegularFile returns an absolute path and metadata of a regular file.
+// File symlinks are resolved when possible; otherwise the original path is kept.
+func ResolveRegularFile(path string) (string, os.FileInfo, error) {
+	path, err := filepath.Abs(path)
+	if err != nil {
+		return "", nil, fmt.Errorf("failed to resolve file path: %w", err)
+	}
+	info, err := os.Lstat(path)
+	if err != nil {
+		return "", nil, fmt.Errorf("failed to inspect file %q: %w", path, err)
+	}
+	if info.Mode()&os.ModeSymlink != 0 {
+		// Best effort: EvalSymlinks may fail when junctions are involved.
+		if resolved, err := filepath.EvalSymlinks(path); err == nil {
+			path = resolved
+		}
+		info, err = os.Stat(path)
+		if err != nil {
+			return "", nil, fmt.Errorf("failed to inspect file %q: %w", path, err)
+		}
+	}
+	if !info.Mode().IsRegular() {
+		return "", nil, fmt.Errorf("file is not a regular file: %s", path)
+	}
+	// Hard links are not handled.
+	return path, info, nil
+}

main/commands/all/lua/sign.go

@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 
 	xlua "github.com/xtls/xray-core/common/lua"
+	"github.com/xtls/xray-core/common/platform"
 	"github.com/xtls/xray-core/main/commands/base"
 )
 
@@ -32,15 +33,15 @@ func executeSign(cmd *base.Command, args []string) {
 		cmd.Usage()
 	}
 
-	info, err := os.Stat(args[0])
+	input, info, err := platform.ResolveRegularFile(args[0])
 	if err != nil {
 		base.Fatalf("failed to inspect Lua file: %s", err)
 	}
-	if !info.Mode().IsRegular() {
-		base.Fatalf("Lua input is not a regular file: %s", args[0])
+	if filepath.Ext(input) != ".lua" {
+		base.Fatalf("Lua file extension must be .lua")
 	}
 
-	code, err := os.ReadFile(args[0])
+	code, err := os.ReadFile(input)
 	if err != nil {
 		base.Fatalf("failed to read Lua file: %s", err)
 	}
@@ -58,7 +59,7 @@ func executeSign(cmd *base.Command, args []string) {
 	}
 	output := *signOutput
 	if output == "" {
-		output = args[0]
+		output = input
 	}
 	if err := writeSignedFile(output, signed, info.Mode().Perm()); err != nil {
 		base.Fatalf("failed to write signed Lua file: %s", err)
@@ -66,15 +67,9 @@ func executeSign(cmd *base.Command, args []string) {
 }
 
 func writeSignedFile(path string, code []byte, mode os.FileMode) error {
-	if info, err := os.Stat(path); err == nil {
-		if !info.Mode().IsRegular() {
-			return &os.PathError{Op: "write", Path: path, Err: os.ErrInvalid}
-		}
+	if resolved, info, err := platform.ResolveRegularFile(path); err == nil {
+		path = resolved
 		mode = info.Mode().Perm()
-		path, err = filepath.EvalSymlinks(path)
-		if err != nil {
-			return err
-		}
 	} else if !os.IsNotExist(err) {
 		return err
 	}

main/confloader/external/external.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/xtls/xray-core/common/buf"
 	"github.com/xtls/xray-core/common/errors"
+	"github.com/xtls/xray-core/common/platform"
 	"github.com/xtls/xray-core/common/utils"
 	"github.com/xtls/xray-core/main/commands/base"
 	"github.com/xtls/xray-core/main/confloader"
@@ -58,11 +59,7 @@ func readConfigFile(file *os.File) ([]byte, error) {
 		return nil, err
 	}
 	if info.Mode().IsRegular() {
-		path, err := filepath.Abs(file.Name())
-		if err != nil {
-			return nil, err
-		}
-		path, err = filepath.EvalSymlinks(path)
+		path, _, err := platform.ResolveRegularFile(file.Name())
 		if err != nil {
 			return nil, err
 		}