Add filemanager api

common/ntp/context.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"time"
 
-	"github.com/sagernet/sing/common/service"
+	"github.com/sagernet/sing/service"
 )
 
 func TimeFuncFromContext(ctx context.Context) func() time.Time {

service/filemanager/default.go

@@ -0,0 +1,164 @@
+package filemanager
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+
+	"github.com/sagernet/sing/common/rw"
+	"github.com/sagernet/sing/service"
+)
+
+var _ Manager = (*defaultManager)(nil)
+
+type defaultManager struct {
+	basePath string
+	tempPath string
+	chown    bool
+	userID   int
+	groupID  int
+}
+
+func WithDefault(ctx context.Context, basePath string, tempPath string, userID int, groupID int) context.Context {
+	chown := userID != os.Getuid() || groupID != os.Getgid()
+	if tempPath == "" {
+		tempPath = os.TempDir()
+	}
+	return service.ContextWith[Manager](ctx, &defaultManager{
+		basePath: basePath,
+		tempPath: tempPath,
+		chown:    chown,
+		userID:   userID,
+		groupID:  groupID,
+	})
+}
+
+func (m *defaultManager) BasePath(name string) string {
+	if m.basePath == "" || strings.HasPrefix(name, "/") {
+		return name
+	}
+	return filepath.Join(m.basePath, name)
+}
+
+func (m *defaultManager) OpenFile(name string, flag int, perm os.FileMode) (*os.File, error) {
+	name = m.BasePath(name)
+	willCreate := flag&os.O_CREATE != 0 && !rw.FileExists(name)
+	file, err := os.OpenFile(name, flag, perm)
+	if err != nil {
+		return nil, err
+	}
+	if m.chown && willCreate {
+		err = file.Chown(m.userID, m.groupID)
+		if err != nil {
+			file.Close()
+			os.Remove(file.Name())
+			return nil, err
+		}
+	}
+	return file, nil
+}
+
+func (m *defaultManager) Create(name string) (*os.File, error) {
+	name = m.BasePath(name)
+	file, err := os.Create(name)
+	if err != nil {
+		return nil, err
+	}
+	if m.chown {
+		err = file.Chown(m.userID, m.groupID)
+		if err != nil {
+			file.Close()
+			os.Remove(file.Name())
+			return nil, err
+		}
+	}
+	return file, nil
+}
+
+func (m *defaultManager) CreateTemp(pattern string) (*os.File, error) {
+	file, err := os.CreateTemp(m.tempPath, pattern)
+	if err != nil {
+		return nil, err
+	}
+	if m.chown {
+		err = file.Chown(m.userID, m.groupID)
+		if err != nil {
+			file.Close()
+			os.Remove(file.Name())
+			return nil, err
+		}
+	}
+	return file, nil
+}
+
+func (m *defaultManager) Mkdir(path string, perm os.FileMode) error {
+	path = m.BasePath(path)
+	err := os.Mkdir(path, perm)
+	if err != nil {
+		return err
+	}
+	if m.chown {
+		err = os.Chown(path, m.userID, m.groupID)
+		if err != nil {
+			os.Remove(path)
+			return err
+		}
+	}
+	return nil
+}
+
+func (m *defaultManager) MkdirAll(path string, perm os.FileMode) error {
+	path = m.BasePath(path)
+	dir, err := os.Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return &os.PathError{Op: "mkdir", Path: path, Err: syscall.ENOTDIR}
+	}
+
+	i := len(path)
+	for i > 0 && os.IsPathSeparator(path[i-1]) {
+		i--
+	}
+
+	j := i
+	for j > 0 && !os.IsPathSeparator(path[j-1]) {
+		j--
+	}
+
+	if j > 1 {
+		err = m.MkdirAll(fixRootDirectory(path[:j-1]), perm)
+		if err != nil {
+			return err
+		}
+	}
+
+	err = os.Mkdir(path, perm)
+	if err != nil {
+		dir, err1 := os.Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	if m.chown {
+		err = os.Chown(path, m.userID, m.groupID)
+		if err != nil {
+			os.Remove(path)
+			return err
+		}
+	}
+	return nil
+}
+
+func fixRootDirectory(p string) string {
+	if len(p) == len(`\\?\c:`) {
+		if os.IsPathSeparator(p[0]) && os.IsPathSeparator(p[1]) && p[2] == '?' && os.IsPathSeparator(p[3]) && p[5] == ':' {
+			return p + `\`
+		}
+	}
+	return p
+}

service/filemanager/manager.go

@@ -0,0 +1,84 @@
+package filemanager
+
+import (
+	"context"
+	"os"
+
+	"github.com/sagernet/sing/service"
+)
+
+type Manager interface {
+	BasePath(name string) string
+	OpenFile(name string, flag int, perm os.FileMode) (*os.File, error)
+	Create(name string) (*os.File, error)
+	CreateTemp(pattern string) (*os.File, error)
+	Mkdir(path string, perm os.FileMode) error
+	MkdirAll(path string, perm os.FileMode) error
+}
+
+func BasePath(ctx context.Context, name string) string {
+	manager := service.FromContext[Manager](ctx)
+	if manager == nil {
+		return name
+	}
+	return manager.BasePath(name)
+}
+
+func OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (*os.File, error) {
+	manager := service.FromContext[Manager](ctx)
+	if manager == nil {
+		return os.OpenFile(name, flag, perm)
+	}
+	return manager.OpenFile(name, flag, perm)
+}
+
+func Create(ctx context.Context, name string) (*os.File, error) {
+	manager := service.FromContext[Manager](ctx)
+	if manager == nil {
+		return os.Create(name)
+	}
+	return manager.Create(name)
+}
+
+func CreateTemp(ctx context.Context, pattern string) (*os.File, error) {
+	manager := service.FromContext[Manager](ctx)
+	if manager == nil {
+		return os.CreateTemp("", pattern)
+	}
+	return manager.CreateTemp(pattern)
+}
+
+func Mkdir(ctx context.Context, path string, perm os.FileMode) error {
+	manager := service.FromContext[Manager](ctx)
+	if manager == nil {
+		return os.Mkdir(path, perm)
+	}
+	return manager.Mkdir(path, perm)
+}
+
+func MkdirAll(ctx context.Context, path string, perm os.FileMode) error {
+	manager := service.FromContext[Manager](ctx)
+	if manager == nil {
+		return os.MkdirAll(path, perm)
+	}
+	return manager.MkdirAll(path, perm)
+}
+
+func WriteFile(ctx context.Context, name string, data []byte, perm os.FileMode) error {
+	manager := service.FromContext[Manager](ctx)
+	if manager == nil {
+		return os.WriteFile(name, data, perm)
+	}
+	file, err := manager.OpenFile(name, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
+	if err != nil {
+		return err
+	}
+	if err != nil {
+		return err
+	}
+	_, err = file.Write(data)
+	if err1 := file.Close(); err1 != nil && err == nil {
+		err = err1
+	}
+	return err
+}