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authorJakob Unterwurzacher2016-02-06 22:54:14 +0100
committerJakob Unterwurzacher2016-02-06 22:54:14 +0100
commite111e20649cfacd7b02dd454d75db879aa2ca53c (patch)
tree5020d3172bfa2462f05898473093dabd3688e64f /internal/nametransform/longnames.go
parent5abd9cec136bfb981c728eb3bf0f92b2282601c6 (diff)
longnames part I: Create and OpenDir work with long filenames > 176 bytes
Todo: Rename, Unlink, Rmdir, Mknod, Mkdir
Diffstat (limited to 'internal/nametransform/longnames.go')
-rw-r--r--internal/nametransform/longnames.go68
1 files changed, 68 insertions, 0 deletions
diff --git a/internal/nametransform/longnames.go b/internal/nametransform/longnames.go
new file mode 100644
index 0000000..e442b64
--- /dev/null
+++ b/internal/nametransform/longnames.go
@@ -0,0 +1,68 @@
+package nametransform
+
+import (
+ "syscall"
+ "path/filepath"
+ "io/ioutil"
+ "crypto/sha256"
+ "encoding/base64"
+ "strings"
+
+ "github.com/rfjakob/gocryptfs/internal/toggledlog"
+)
+
+// Files with long names are stored in two files:
+// gocryptfs.longname.[sha256] <--- File content
+// gocryptfs.longname.[sha256].name <--- File name
+const longNamePrefix = "gocryptfs.longname."
+const longNameSuffix = ".name"
+
+// HashLongName - take the hash of a long string "name" and return
+// "gocryptfs.longname.[sha256]"
+func HashLongName(name string) string {
+ hashBin := sha256.Sum256([]byte(name))
+ hashBase64 := base64.URLEncoding.EncodeToString(hashBin[:])
+ return longNamePrefix + hashBase64
+}
+
+// IsLongName - detect if cName is
+// gocryptfs.longname.* ........ 1
+// gocryptfs.longname.*.name ... 2
+// else ........................ 0
+func IsLongName(cName string) int {
+ if !strings.HasPrefix(cName, longNamePrefix) {
+ return 0
+ }
+ if strings.HasSuffix(cName, longNameSuffix) {
+ return 2
+ }
+ return 1
+}
+
+// ReadLongName - read "path".name
+func ReadLongName(path string) (string, error) {
+ content, err := ioutil.ReadFile(path+longNameSuffix)
+ if err != nil {
+ toggledlog.Warn.Printf("ReadLongName: %v", err)
+ }
+ return string(content), err
+}
+
+// WriteLongName -
+func (n *NameTransform) WriteLongName(cDir string, hashedName string, plainName string) (err error) {
+ if len(plainName) > syscall.NAME_MAX {
+ return syscall.ENAMETOOLONG
+ }
+
+ dirIV, err := ReadDirIV(cDir)
+ if err != nil {
+ toggledlog.Warn.Printf("WriteLongName: %v", err)
+ return err
+ }
+ cName := n.EncryptName(plainName, dirIV)
+ err = ioutil.WriteFile(filepath.Join(cDir, hashedName + longNameSuffix), []byte(cName), 0600)
+ if err != nil {
+ toggledlog.Warn.Printf("WriteLongName: %v", err)
+ }
+ return err
+}