From f6ded09e36a679695354f4b9bc74242ef399be09 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sun, 21 Jun 2020 13:25:12 +0200
Subject: v2api: implement Create

---
 internal/fusefrontend/node.go | 71 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

(limited to 'internal/fusefrontend/node.go')

diff --git a/internal/fusefrontend/node.go b/internal/fusefrontend/node.go
index 9074f72..28e606a 100644
--- a/internal/fusefrontend/node.go
+++ b/internal/fusefrontend/node.go
@@ -2,6 +2,7 @@ package fusefrontend
 
 import (
 	"context"
+	"os"
 	"path/filepath"
 	"syscall"
 
@@ -10,7 +11,9 @@ import (
 	"github.com/hanwen/go-fuse/v2/fs"
 	"github.com/hanwen/go-fuse/v2/fuse"
 
+	"github.com/rfjakob/gocryptfs/internal/nametransform"
 	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
 )
 
 // Node is a file or directory in the filesystem tree
@@ -31,6 +34,9 @@ func (n *Node) rootNode() *RootNode {
 func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*fs.Inode, syscall.Errno) {
 	rn := n.rootNode()
 	p := filepath.Join(n.path(), name)
+	if rn.isFiltered(p) {
+		return nil, syscall.EPERM
+	}
 	dirfd, cName, err := rn.openBackingDir(p)
 	if err != nil {
 		return nil, fs.ToErrno(err)
@@ -71,3 +77,68 @@ func (n *Node) Getattr(ctx context.Context, f fs.FileHandle, out *fuse.AttrOut)
 	out.Attr.FromStat(st)
 	return 0
 }
+
+func (n *Node) Create(ctx context.Context, name string, flags uint32, mode uint32, out *fuse.EntryOut) (inode *fs.Inode, fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
+	rn := n.rootNode()
+	path := filepath.Join(n.path(), name)
+	if rn.isFiltered(path) {
+		return nil, nil, 0, syscall.EPERM
+	}
+	dirfd, cName, err := rn.openBackingDir(path)
+	if err != nil {
+		return nil, nil, 0, fs.ToErrno(err)
+	}
+	defer syscall.Close(dirfd)
+
+	fd := -1
+	// Make sure context is nil if we don't want to preserve the owner
+	if !rn.args.PreserveOwner {
+		ctx = nil
+	}
+	newFlags := rn.mangleOpenFlags(flags)
+	// Handle long file name
+	if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
+		// Create ".name"
+		err = rn.nameTransform.WriteLongNameAt(dirfd, cName, path)
+		if err != nil {
+			return nil, nil, 0, fs.ToErrno(err)
+		}
+		// Create content
+		fd, err = syscallcompat.OpenatUserCtx(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx)
+		if err != nil {
+			nametransform.DeleteLongNameAt(dirfd, cName)
+		}
+	} else {
+		// Create content, normal (short) file name
+		fd, err = syscallcompat.OpenatUserCtx(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx)
+	}
+	if err != nil {
+		// xfstests generic/488 triggers this
+		if err == syscall.EMFILE {
+			var lim syscall.Rlimit
+			syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
+			tlog.Warn.Printf("Create %q: too many open files. Current \"ulimit -n\": %d", cName, lim.Cur)
+		}
+		return nil, nil, 0, fs.ToErrno(err)
+	}
+
+	// Get device number and inode number into `st`
+	st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
+	if err != nil {
+		return nil, nil, 0, fs.ToErrno(err)
+	}
+	// Get unique inode number
+	rn.inoMap.TranslateStat(st)
+	out.Attr.FromStat(st)
+	// Create child node
+	id := fs.StableAttr{
+		Mode: uint32(st.Mode),
+		Gen:  1,
+		Ino:  st.Ino,
+	}
+	node := &Node{}
+	ch := n.NewInode(ctx, node, id)
+
+	f := os.NewFile(uintptr(fd), cName)
+	return ch, NewFile2(f, rn, st), 0, 0
+}
-- 
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