v2api: implement Symlink

libgocryptfs
Jakob Unterwurzacher 2 years ago
parent c35b575d5f
commit 250dbc6436
  1. 49
      internal/fusefrontend/node.go
  2. 2
      internal/fusefrontend/node_api_check.go
  3. 14
      internal/fusefrontend/root_node.go

@ -400,3 +400,52 @@ func (n *Node) Link(ctx context.Context, target fs.InodeEmbedder, name string, o
inode = n.newChild(ctx, st, out)
return inode, 0
}
// Symlink - FUSE call. Create a symlink.
//
// Symlink-safe through use of Symlinkat.
func (n *Node) Symlink(ctx context.Context, target, name string, out *fuse.EntryOut) (inode *fs.Inode, errno syscall.Errno) {
dirfd, cName, errno := n.prepareAtSyscall(name)
if errno != 0 {
return
}
defer syscall.Close(dirfd)
// Make sure context is nil if we don't want to preserve the owner
rn := n.rootNode()
if !rn.args.PreserveOwner {
ctx = nil
}
cTarget := target
if !rn.args.PlaintextNames {
// Symlinks are encrypted like file contents (GCM) and base64-encoded
cTarget = rn.encryptSymlinkTarget(target)
}
// Create ".name" file to store long file name (except in PlaintextNames mode)
var err error
ctx2 := toFuseCtx(ctx)
if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
err = rn.nameTransform.WriteLongNameAt(dirfd, cName, name)
if err != nil {
errno = fs.ToErrno(err)
return
}
// Create "gocryptfs.longfile." symlink
err = syscallcompat.SymlinkatUser(cTarget, dirfd, cName, ctx2)
if err != nil {
nametransform.DeleteLongNameAt(dirfd, cName)
}
} else {
// Create symlink
err = syscallcompat.SymlinkatUser(cTarget, dirfd, cName, ctx2)
}
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
errno = fs.ToErrno(err)
return
}
inode = n.newChild(ctx, st, out)
return inode, 0
}

@ -19,6 +19,7 @@ var _ = (fs.NodeSetattrer)((*Node)(nil))
var _ = (fs.NodeStatfser)((*Node)(nil))
var _ = (fs.NodeMknoder)((*Node)(nil))
var _ = (fs.NodeLinker)((*Node)(nil))
var _ = (fs.NodeSymlinker)((*Node)(nil))
/* TODO
var _ = (fs.NodeGetxattrer)((*Node)(nil))
@ -26,6 +27,5 @@ var _ = (fs.NodeSetxattrer)((*Node)(nil))
var _ = (fs.NodeRemovexattrer)((*Node)(nil))
var _ = (fs.NodeListxattrer)((*Node)(nil))
var _ = (fs.NodeCopyFileRanger)((*Node)(nil))
var _ = (fs.NodeSymlinker)((*Node)(nil))
var _ = (fs.NodeRenamer)((*Node)(nil))
*/

@ -245,3 +245,17 @@ func (rn *RootNode) openBackingDir(relPath string) (dirfd int, cName string, err
}
return dirfd, cName, nil
}
// encryptSymlinkTarget: "data" is encrypted like file contents (GCM)
// and base64-encoded.
// The empty string encrypts to the empty string.
//
// Symlink-safe because it does not do any I/O.
func (rn *RootNode) encryptSymlinkTarget(data string) (cData64 string) {
if data == "" {
return ""
}
cData := rn.contentEnc.EncryptBlock([]byte(data), 0, nil)
cData64 = rn.nameTransform.B64EncodeToString(cData)
return cData64
}

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