From 3288d987032fde33ff3cd837b1a0feb612b9710b Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher <jakobunt@gmail.com>
Date: Mon, 27 Jun 2016 00:25:56 +0200
Subject: [PATCH] fusefrontend: fix PlaintextNames versions of Mkdir, Rmdir

The "!fs.args.DirIV" special case was removed by b17f0465c7
but that, by accident, also removed the handling for
PlaintextNames.

Re-add it as an explicit PlaintextNames special case.

Also adds support for removing directories that miss their
gocryptfs.diriv file for some reason.
---
 internal/fusefrontend/fs_dir.go | 98 +++++++++++++++++++--------------
 1 file changed, 57 insertions(+), 41 deletions(-)

diff --git a/internal/fusefrontend/fs_dir.go b/internal/fusefrontend/fs_dir.go
index 80a66ca..9547ce6 100644
--- a/internal/fusefrontend/fs_dir.go
+++ b/internal/fusefrontend/fs_dir.go
@@ -4,6 +4,7 @@ package fusefrontend
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -46,6 +47,11 @@ func (fs *FS) Mkdir(newPath string, mode uint32, context *fuse.Context) (code fu
 	if err != nil {
 		return fuse.ToStatus(err)
 	}
+	if fs.args.PlaintextNames {
+		err = os.Mkdir(cPath, os.FileMode(mode))
+		return fuse.ToStatus(err)
+	}
+
 	// We need write and execute permissions to create gocryptfs.diriv
 	origMode := mode
 	mode = mode | 0300
@@ -95,7 +101,10 @@ func (fs *FS) Rmdir(path string, context *fuse.Context) (code fuse.Status) {
 	if err != nil {
 		return fuse.ToStatus(err)
 	}
-
+	if fs.args.PlaintextNames {
+		err = syscall.Rmdir(cPath)
+		return fuse.ToStatus(err)
+	}
 	parentDir := filepath.Dir(cPath)
 	parentDirFd, err := os.Open(parentDir)
 	if err != nil {
@@ -146,49 +155,56 @@ func (fs *FS) Rmdir(path string, context *fuse.Context) (code fuse.Status) {
 	defer dirfd.Close()
 
 	children, err := dirfd.Readdirnames(10)
-	if err != nil {
+	if err == nil {
+		// If the directory is not empty besides gocryptfs.diriv, do not even
+		// attempt the dance around gocryptfs.diriv.
+		if len(children) > 1 {
+			return fuse.ToStatus(syscall.ENOTEMPTY)
+		}
+		// Move "gocryptfs.diriv" to the parent dir as "gocryptfs.diriv.rmdir.XYZ"
+		tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", cryptocore.RandUint64())
+		tlog.Debug.Printf("Rmdir: Renaming %s to %s", nametransform.DirIVFilename, tmpName)
+		// The directory is in an inconsistent state between rename and rmdir.
+		// Protect against concurrent readers.
+		fs.dirIVLock.Lock()
+		defer fs.dirIVLock.Unlock()
+		err = syscall.Renameat(int(dirfd.Fd()), nametransform.DirIVFilename,
+			int(parentDirFd.Fd()), tmpName)
+		if err != nil {
+			tlog.Warn.Printf("Rmdir: Renaming %s to %s failed: %v",
+				nametransform.DirIVFilename, tmpName, err)
+			return fuse.ToStatus(err)
+		}
+		// Actual Rmdir
+		// TODO Use syscall.Unlinkat with the AT_REMOVEDIR flag once it is available
+		// in Go
+		err = syscall.Rmdir(cPath)
+		if err != nil {
+			// This can happen if another file in the directory was created in the
+			// meantime, undo the rename
+			err2 := syscall.Renameat(int(parentDirFd.Fd()), tmpName,
+				int(dirfd.Fd()), nametransform.DirIVFilename)
+			if err != nil {
+				tlog.Warn.Printf("Rmdir: Rename rollback failed: %v", err2)
+			}
+			return fuse.ToStatus(err)
+		}
+		// Delete "gocryptfs.diriv.rmdir.XYZ"
+		err = syscall.Unlinkat(int(parentDirFd.Fd()), tmpName)
+		if err != nil {
+			tlog.Warn.Printf("Rmdir: Could not clean up %s: %v", tmpName, err)
+		}
+	} else if err == io.EOF {
+		// The directory is empty
+		tlog.Warn.Printf("Rmdir: %q: gocryptfs.diriv is missing", cPath)
+		err = syscall.Rmdir(cPath)
+		if err != nil {
+			return fuse.ToStatus(err)
+		}
+	} else {
 		tlog.Warn.Printf("Rmdir: Readdirnames: %v", err)
 		return fuse.ToStatus(err)
 	}
-	// If the directory is not empty besides gocryptfs.diriv, do not even
-	// attempt the dance around gocryptfs.diriv.
-	if len(children) > 1 {
-		return fuse.ToStatus(syscall.ENOTEMPTY)
-	}
-
-	// Move "gocryptfs.diriv" to the parent dir as "gocryptfs.diriv.rmdir.XYZ"
-	tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", cryptocore.RandUint64())
-	tlog.Debug.Printf("Rmdir: Renaming %s to %s", nametransform.DirIVFilename, tmpName)
-	// The directory is in an inconsistent state between rename and rmdir.
-	// Protect against concurrent readers.
-	fs.dirIVLock.Lock()
-	defer fs.dirIVLock.Unlock()
-	err = syscall.Renameat(int(dirfd.Fd()), nametransform.DirIVFilename,
-		int(parentDirFd.Fd()), tmpName)
-	if err != nil {
-		tlog.Warn.Printf("Rmdir: Renaming %s to %s failed: %v",
-			nametransform.DirIVFilename, tmpName, err)
-		return fuse.ToStatus(err)
-	}
-	// Actual Rmdir
-	// TODO Use syscall.Unlinkat with the AT_REMOVEDIR flag once it is available
-	// in Go
-	err = syscall.Rmdir(cPath)
-	if err != nil {
-		// This can happen if another file in the directory was created in the
-		// meantime, undo the rename
-		err2 := syscall.Renameat(int(parentDirFd.Fd()), tmpName,
-			int(dirfd.Fd()), nametransform.DirIVFilename)
-		if err != nil {
-			tlog.Warn.Printf("Rmdir: Rename rollback failed: %v", err2)
-		}
-		return fuse.ToStatus(err)
-	}
-	// Delete "gocryptfs.diriv.rmdir.XYZ"
-	err = syscall.Unlinkat(int(parentDirFd.Fd()), tmpName)
-	if err != nil {
-		tlog.Warn.Printf("Rmdir: Could not clean up %s: %v", tmpName, err)
-	}
 	// Delete .name file
 	if nametransform.IsLongContent(cName) {
 		nametransform.DeleteLongName(parentDirFd, cName)