From 815666ab119f4b2e6ac801c66d4b5c06a970f1cc Mon Sep 17 00:00:00 2001
From: Han-Wen Nienhuys <hanwen@google.com>
Date: Mon, 24 Sep 2018 10:09:49 +0200
Subject: [PATCH] fuse/test: clarify umask semantics

Improve test to eliminate backing FS semantics
---
 fuse/test/loopback_test.go | 28 +-----------
 fuse/test/umask_test.go    | 91 ++++++++++++++++++++++++++++++++++++++
 fuse/types.go              |  3 ++
 fuse/types_linux.go        | 14 ++++--
 4 files changed, 105 insertions(+), 31 deletions(-)
 create mode 100644 fuse/test/umask_test.go

diff --git a/fuse/test/loopback_test.go b/fuse/test/loopback_test.go
index 36cdea4f0..b672deb56 100644
--- a/fuse/test/loopback_test.go
+++ b/fuse/test/loopback_test.go
@@ -11,7 +11,6 @@ import (
 	"io/ioutil"
 	"math/rand"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"reflect"
 	"runtime"
@@ -25,8 +24,6 @@ import (
 	"github.com/hanwen/go-fuse/internal/testutil"
 )
 
-const mode uint32 = 0757
-
 type testCase struct {
 	tmpDir string
 	orig   string
@@ -148,6 +145,7 @@ func TestReadThrough(t *testing.T) {
 
 	content := randomData(125)
 	tc.WriteFile(tc.origFile, content, 0700)
+	var mode uint32 = 0757
 	err := os.Chmod(tc.mountFile, os.FileMode(mode))
 	if err != nil {
 		t.Fatalf("Chmod failed: %v", err)
@@ -916,31 +914,7 @@ func TestDoubleOpen(t *testing.T) {
 		t.Fatalf("OpenFile failed: %v", err)
 	}
 	defer rwFile.Close()
-}
 
-func TestUmask(t *testing.T) {
-	tc := NewTestCase(t)
-	defer tc.Cleanup()
-
-	// Make sure system setting does not affect test.
-	fn := tc.mnt + "/file"
-	mask := 020
-	cmd := exec.Command("/bin/sh", "-c",
-		fmt.Sprintf("umask %o && mkdir %s", mask, fn))
-	if err := cmd.Run(); err != nil {
-		t.Fatalf("cmd.Run: %v", err)
-	}
-
-	fi, err := os.Lstat(fn)
-	if err != nil {
-		t.Fatalf("Lstat failed: %v", err)
-	}
-
-	expect := mask ^ 0777
-	got := int(fi.Mode().Perm())
-	if got != expect {
-		t.Errorf("got %o, expect mode %o for file %s", got, expect, fn)
-	}
 }
 
 // Check that chgrp(1) works
diff --git a/fuse/test/umask_test.go b/fuse/test/umask_test.go
new file mode 100644
index 000000000..941fa596f
--- /dev/null
+++ b/fuse/test/umask_test.go
@@ -0,0 +1,91 @@
+// Copyright 2016 the Go-FUSE Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package test
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"testing"
+
+	"github.com/hanwen/go-fuse/fuse"
+	"github.com/hanwen/go-fuse/fuse/nodefs"
+	"github.com/hanwen/go-fuse/fuse/pathfs"
+	"github.com/hanwen/go-fuse/internal/testutil"
+)
+
+type umaskFS struct {
+	pathfs.FileSystem
+
+	mkdirMode  uint32
+	createMode uint32
+}
+
+func (fs *umaskFS) Create(name string, flags uint32, mode uint32, context *fuse.Context) (file nodefs.File, code fuse.Status) {
+	fs.createMode = mode
+	return fs.FileSystem.Create(name, flags, mode, context)
+}
+
+func (fs *umaskFS) Mkdir(name string, mode uint32, context *fuse.Context) (code fuse.Status) {
+	fs.mkdirMode = mode
+	return fs.FileSystem.Mkdir(name, mode, context)
+}
+
+func TestUmask(t *testing.T) {
+	tmpDir := testutil.TempDir()
+	orig := tmpDir + "/orig"
+	mnt := tmpDir + "/mnt"
+
+	os.Mkdir(orig, 0700)
+	os.Mkdir(mnt, 0700)
+
+	var pfs pathfs.FileSystem
+	pfs = pathfs.NewLoopbackFileSystem(orig)
+	pfs = pathfs.NewLockingFileSystem(pfs)
+	ufs := &umaskFS{FileSystem: pfs}
+
+	pathFs := pathfs.NewPathNodeFs(ufs, &pathfs.PathNodeFsOptions{
+		ClientInodes: true})
+	connector := nodefs.NewFileSystemConnector(pathFs.Root(),
+		&nodefs.Options{
+			EntryTimeout:        testTtl,
+			AttrTimeout:         testTtl,
+			NegativeTimeout:     0.0,
+			Debug:               testutil.VerboseTest(),
+			LookupKnownChildren: true,
+		})
+	server, err := fuse.NewServer(
+		fuse.NewRawFileSystem(connector.RawFS()), mnt, &fuse.MountOptions{
+			SingleThreaded: true,
+			Debug:          testutil.VerboseTest(),
+		})
+	if err != nil {
+		t.Fatal("NewServer:", err)
+	}
+
+	go server.Serve()
+	if err := server.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
+
+	// Make sure system setting does not affect test.
+	mask := 020
+	cmd := exec.Command("/bin/sh", "-c",
+		fmt.Sprintf("umask %o && cd %s && mkdir x && touch y", mask, mnt))
+	if err := cmd.Run(); err != nil {
+		t.Fatalf("cmd.Run: %v", err)
+	}
+
+	if err := server.Unmount(); err != nil {
+		t.Fatalf("Unmount %v", err)
+	}
+
+	if got, want := ufs.mkdirMode&0777, uint32(0757); got != want {
+		t.Errorf("got dirMode %o want %o", got, want)
+	}
+	if got, want := ufs.createMode&0666, uint32(0646); got != want {
+		t.Errorf("got createMode %o want %o", got, want)
+	}
+}
diff --git a/fuse/types.go b/fuse/types.go
index 8b1fa2217..f2d63c4c6 100644
--- a/fuse/types.go
+++ b/fuse/types.go
@@ -86,6 +86,9 @@ type _BatchForgetIn struct {
 
 type MkdirIn struct {
 	InHeader
+
+	// The mode for the new directory. The calling process' umask
+	// is already factored into the mode.
 	Mode  uint32
 	Umask uint32
 }
diff --git a/fuse/types_linux.go b/fuse/types_linux.go
index dc5db794f..02bdb4ad2 100644
--- a/fuse/types_linux.go
+++ b/fuse/types_linux.go
@@ -61,14 +61,20 @@ func (g *GetAttrIn) Fh() uint64 {
 
 type CreateIn struct {
 	InHeader
-	Flags  uint32
-	Mode   uint32
-	Umask  uint32
-	Pading uint32
+	Flags uint32
+
+	// Mode for the new file; already takes Umask into account.
+	Mode uint32
+
+	// Umask used for this create call.
+	Umask   uint32
+	Padding uint32
 }
 
 type MknodIn struct {
 	InHeader
+
+	// Mode to use, including the Umask value
 	Mode    uint32
 	Rdev    uint32
 	Umask   uint32