libgocryptfs/internal/fusefrontend/node.go

145 lines
3.7 KiB
Go

package fusefrontend
import (
"context"
"os"
"path/filepath"
"syscall"
"golang.org/x/sys/unix"
"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
// in a gocryptfs mount.
type Node struct {
fs.Inode
}
// path returns the relative plaintext path of this node
func (n *Node) path() string {
return n.Path(n.Root())
}
func (n *Node) rootNode() *RootNode {
return n.Root().Operations().(*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)
}
defer syscall.Close(dirfd)
// Get device number and inode number into `st`
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
return nil, 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)
return ch, 0
}
func (n *Node) Getattr(ctx context.Context, f fs.FileHandle, out *fuse.AttrOut) syscall.Errno {
rn := n.rootNode()
dirfd, cName, err := rn.openBackingDir(n.path())
if err != nil {
return fs.ToErrno(err)
}
defer syscall.Close(dirfd)
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
return fs.ToErrno(err)
}
rn.inoMap.TranslateStat(st)
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
}