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authorJakob Unterwurzacher2020-08-02 13:25:53 +0200
committerJakob Unterwurzacher2020-08-02 13:25:53 +0200
commit4674bac8381838718f0defba0f2e0d9eba2a41a3 (patch)
treea33138d2d6c499c19a880cba515d2fc7665e6b28 /internal/fusefrontend_reverse/virtualfile.go
parent47d8f56b7f9a7dee760deeaeae3e044c0ab65d6a (diff)
v2api/reverse: implement Lookup for gocryptfs.conf & gocryptfs.diriv
Diffstat (limited to 'internal/fusefrontend_reverse/virtualfile.go')
-rw-r--r--internal/fusefrontend_reverse/virtualfile.go100
1 files changed, 100 insertions, 0 deletions
diff --git a/internal/fusefrontend_reverse/virtualfile.go b/internal/fusefrontend_reverse/virtualfile.go
index a92c127..a7f6913 100644
--- a/internal/fusefrontend_reverse/virtualfile.go
+++ b/internal/fusefrontend_reverse/virtualfile.go
@@ -1,7 +1,16 @@
package fusefrontend_reverse
import (
+ "context"
+ "log"
"syscall"
+
+ "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/inomap"
+ "github.com/rfjakob/gocryptfs/internal/nametransform"
)
const (
@@ -13,3 +22,94 @@ const (
inoTagDirIV = 1
inoTagNameFile = 2
)
+
+type fileType int
+
+// Values returned by lookupFileType
+const (
+ // A real file/directory/symlink in the backing plaintext directory
+ typeReal fileType = iota
+ // A DirIV (gocryptfs.diriv) file
+ typeDiriv
+ // A gocryptfs.longname.*.name file for a file with a long name
+ typeName
+ // The config file gocryptfs.conf
+ typeConfig
+)
+
+// lookupFileType returns the type of child file name
+// (one of the fileType constants above). Called from Lookup().
+func (n *Node) lookupFileType(cName string) fileType {
+ rn := n.rootNode()
+ // In -plaintextname mode, neither diriv nor longname files exist.
+ if !rn.args.PlaintextNames {
+ // Is it a gocryptfs.diriv file?
+ if cName == nametransform.DirIVFilename {
+ return typeDiriv
+ }
+ // Is it a gocryptfs.longname.*.name file?
+ if t := nametransform.NameType(cName); t == nametransform.LongNameFilename {
+ return typeName
+ }
+ }
+ // gocryptfs.conf in the root directory. This is passed through to
+ // .gocryptfs.reverse.conf in the backing plaintext directory.
+ if n.isRoot() && !rn.args.ConfigCustom && cName == configfile.ConfDefaultName {
+ return typeConfig
+ }
+ return typeReal
+}
+
+type virtualFile struct {
+ fs.Inode
+
+ // file content
+ content []byte
+ // attributes for Getattr()
+ attr fuse.Attr
+}
+
+// newVirtualFile creates a new in-memory file that does not have a representation
+// on disk. "content" is the file content. Timestamps and file owner are copied
+// from "parentFile" (file descriptor).
+// For a "gocryptfs.diriv" file, you would use the parent directory as
+// "parentFile".
+func (n *Node) newVirtualFile(content []byte, parentStat *syscall.Stat_t, inoTag uint8) (vf *virtualFile, errno syscall.Errno) {
+ if inoTag == 0 {
+ log.Panicf("BUG: inoTag for virtual file is zero - this will cause ino collisions!")
+ }
+
+ // Adjust inode number and size
+ rn := n.rootNode()
+ st := parentStat
+ q := inomap.NewQIno(uint64(st.Dev), inoTag, uint64(st.Ino))
+ st.Ino = rn.inoMap.Translate(q)
+ st.Size = int64(len(content))
+ st.Mode = virtualFileMode
+ st.Nlink = 1
+ var a fuse.Attr
+ a.FromStat(st)
+
+ vf = &virtualFile{content: content, attr: a}
+ return
+}
+
+// Open - FUSE call
+func (f *virtualFile) Open(ctx context.Context, flags uint32) (fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
+ return nil, fuse.FOPEN_KEEP_CACHE, 0
+}
+
+// GetAttr - FUSE call
+func (f *virtualFile) Getattr(ctx context.Context, fh fs.FileHandle, out *fuse.AttrOut) syscall.Errno {
+ out.Attr = f.attr
+ return 0
+}
+
+// Read - FUSE call
+func (f *virtualFile) Read(ctx context.Context, fh fs.FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
+ end := int(off) + len(dest)
+ if end > len(f.content) {
+ end = len(f.content)
+ }
+ return fuse.ReadResultData(f.content[off:end]), 0
+}