request-server: add lstat support

request-example.go

@@ -213,6 +213,12 @@ func (fs *root) Filelist(r *Request) (ListerAt, error) {
 		}
 		return listerat(list), nil
 	case "Stat":
+		if file.symlink != "" {
+			file, err = fs.fetch(file.symlink)
+			if err != nil {
+				return nil, err
+			}
+		}
 		return listerat([]os.FileInfo{file}), nil
 	case "Readlink":
 		if file.symlink != "" {
@@ -226,6 +232,22 @@ func (fs *root) Filelist(r *Request) (ListerAt, error) {
 	return nil, nil
 }
 
+// implements LstatFileLister interface
+func (fs *root) Lstat(r *Request) (ListerAt, error) {
+	if fs.mockErr != nil {
+		return nil, fs.mockErr
+	}
+	_ = r.WithContext(r.Context()) // initialize context for deadlock testing
+	fs.filesLock.Lock()
+	defer fs.filesLock.Unlock()
+
+	file, err := fs.fetch(r.Filepath)
+	if err != nil {
+		return nil, err
+	}
+	return listerat([]os.FileInfo{file}), nil
+}
+
 // In memory file-system-y thing that the Hanlders live on
 type root struct {
 	*memFile

request-interfaces.go

@@ -63,6 +63,13 @@ type FileLister interface {
 	Filelist(*Request) (ListerAt, error)
 }
 
+// LstatFileLister is a FileLister that implements the Lstat method.
+// If this interface is implemented Lstat requests will call it
+// otherwise they will be handled in the same way as Stat
+type LstatFileLister interface {
+	Lstat(*Request) (ListerAt, error)
+}
+
 // ListerAt does for file lists what io.ReaderAt does for files.
 // ListAt should return the number of entries copied and an io.EOF
 // error if at end of list. This is testable by comparing how many you

request-server_test.go

@@ -405,6 +405,19 @@ func TestRequestStatFail(t *testing.T) {
 	checkRequestServerAllocator(t, p)
 }
 
+func TestRequestLstat(t *testing.T) {
+	p := clientRequestServerPair(t)
+	defer p.Close()
+	_, err := putTestFile(p.cli, "/foo", "hello")
+	require.NoError(t, err)
+	err = p.cli.Symlink("/foo", "/bar")
+	require.NoError(t, err)
+	fi, err := p.cli.Lstat("/bar")
+	require.NoError(t, err)
+	assert.True(t, fi.Mode()&os.ModeSymlink == os.ModeSymlink)
+	checkRequestServerAllocator(t, p)
+}
+
 func TestRequestLink(t *testing.T) {
 	p := clientRequestServerPair(t)
 	defer p.Close()

request.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"strings"
 	"sync"
 	"syscall"
 
@@ -213,7 +214,7 @@ func (r *Request) call(handlers Handlers, pkt requestPacket, alloc *allocator, o
 		return filecmd(handlers.FileCmd, r, pkt)
 	case "List":
 		return filelist(handlers.FileList, r, pkt)
-	case "Stat", "Readlink":
+	case "Stat", "Lstat", "Readlink":
 		return filestat(handlers.FileList, r, pkt)
 	default:
 		return statusFromError(pkt,
@@ -405,7 +406,20 @@ func filelist(h FileLister, r *Request, pkt requestPacket) responsePacket {
 }
 
 func filestat(h FileLister, r *Request, pkt requestPacket) responsePacket {
-	lister, err := h.Filelist(r)
+	var lister ListerAt
+	var err error
+
+	if r.Method == "Lstat" {
+		if lstatFileLister, ok := h.(LstatFileLister); ok {
+			lister, err = lstatFileLister.Lstat(r)
+		} else {
+			// LstatFileLister not implemented handle this request as a Stat
+			r.Method = "Stat"
+			lister, err = h.Filelist(r)
+		}
+	} else {
+		lister, err = h.Filelist(r)
+	}
 	if err != nil {
 		return statusFromError(pkt, err)
 	}
@@ -414,12 +428,12 @@ func filestat(h FileLister, r *Request, pkt requestPacket) responsePacket {
 	finfo = finfo[:n] // avoid need for nil tests below
 
 	switch r.Method {
-	case "Stat":
+	case "Stat", "Lstat":
 		if err != nil && err != io.EOF {
 			return statusFromError(pkt, err)
 		}
 		if n == 0 {
-			err = &os.PathError{Op: "stat", Path: r.Filepath,
+			err = &os.PathError{Op: strings.ToLower(r.Method), Path: r.Filepath,
 				Err: syscall.ENOENT}
 			return statusFromError(pkt, err)
 		}
@@ -466,8 +480,10 @@ func requestMethod(p requestPacket) (method string) {
 		method = "Symlink"
 	case *sshFxpRemovePacket:
 		method = "Remove"
-	case *sshFxpStatPacket, *sshFxpLstatPacket, *sshFxpFstatPacket:
+	case *sshFxpStatPacket, *sshFxpFstatPacket:
 		method = "Stat"
+	case *sshFxpLstatPacket:
+		method = "Lstat"
 	case *sshFxpRmdirPacket:
 		method = "Rmdir"
 	case *sshFxpReadlinkPacket: