libgocryptfs/internal/fusefrontend_reverse/node.go

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package fusefrontend_reverse
import (
"context"
"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/configfile"
"github.com/rfjakob/gocryptfs/internal/pathiv"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
)
// Node is a file or directory in the filesystem tree
// in a `gocryptfs -reverse` mount.
type Node struct {
fs.Inode
}
// Lookup - FUSE call for discovering a file.
func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (ch *fs.Inode, errno syscall.Errno) {
dirfd := int(-1)
pName := ""
t := n.lookupFileType(name)
// gocryptfs.conf
if t == typeConfig {
var err error
rn := n.rootNode()
dirfd, err = syscallcompat.OpenDirNofollow(rn.args.Cipherdir, "")
if err != nil {
errno = fs.ToErrno(err)
return
}
defer syscall.Close(dirfd)
pName = configfile.ConfReverseName
} else if t == typeDiriv {
// gocryptfs.diriv
dirfd, pName, errno = n.prepareAtSyscall("")
if errno != 0 {
return
}
defer syscall.Close(dirfd)
st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
errno = fs.ToErrno(err)
return
}
content := pathiv.Derive(n.Path(), pathiv.PurposeDirIV)
var vf *virtualFile
vf, errno = n.newVirtualFile(content, st, inoTagDirIV)
if errno != 0 {
return nil, errno
}
out.Attr = vf.attr
// Create child node
id := fs.StableAttr{Mode: uint32(vf.attr.Mode), Gen: 1, Ino: vf.attr.Ino}
ch = n.NewInode(ctx, vf, id)
return
} else if t == typeName {
// gocryptfs.longname.*.name
// TODO
} else if t == typeReal {
// real file
dirfd, pName, errno = n.prepareAtSyscall(name)
if errno != 0 {
return
}
defer syscall.Close(dirfd)
}
// Get device number and inode number into `st`
st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
return nil, fs.ToErrno(err)
}
// Create new inode and fill `out`
ch = n.newChild(ctx, st, out)
if t == typeReal {
// Translate ciphertext size in `out.Attr.Size` to plaintext size
n.translateSize(dirfd, pName, &out.Attr)
}
return ch, 0
}
// GetAttr - FUSE call for stat()ing a file.
//
// GetAttr is symlink-safe through use of openBackingDir() and Fstatat().
func (n *Node) Getattr(ctx context.Context, f fs.FileHandle, out *fuse.AttrOut) (errno syscall.Errno) {
// If the kernel gives us a file handle, use it.
if f != nil {
return f.(fs.FileGetattrer).Getattr(ctx, out)
}
dirfd, pName, errno := n.prepareAtSyscall("")
if errno != 0 {
return
}
defer syscall.Close(dirfd)
st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
return fs.ToErrno(err)
}
// Fix inode number
rn := n.rootNode()
rn.inoMap.TranslateStat(st)
out.Attr.FromStat(st)
// Translate ciphertext size in `out.Attr.Size` to plaintext size
n.translateSize(dirfd, pName, &out.Attr)
if rn.args.ForceOwner != nil {
out.Owner = *rn.args.ForceOwner
}
return 0
}