decrypt: AOSP 10 requires the use of fscrypt

fscrypt aosp doc: https://source.android.com/security/encryption/file-based
kernel fscrypt doc: https://www.kernel.org/doc/html/v4.18/filesystems/fscrypt.html

This commit implements the ability for TWRP to use fscrypt to decrypt
files on the fscrypt implementation. It has been implemented mostly
in a new successor library to e4crypt called libtwrpfscrypt. Most of the
code was ported from AOSP vold.

Notable updates include:
 - updated policy storage by libtar
 - lookup of fbe policies by libtwrpfscrypt
 - threaded keystore operations

Big thanks to Dees_Troy for the initial trailblazing
of encryption in TWRP.

Change-Id: I69cd2eba3693a9914e00213d4943229635d0cdae
diff --git a/crypto/fscrypt/main.cpp b/crypto/fscrypt/main.cpp
new file mode 100644
index 0000000..f0266ae
--- /dev/null
+++ b/crypto/fscrypt/main.cpp
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2016 Team Win Recovery Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "Decrypt.h"
+
+int main(int argc, char *argv[]) {
+	bool ret = false;
+	if (argc < 2) {
+		Decrypt_DE();
+		ret = Decrypt_User(0, "0000");
+	} else if (argc < 3) {
+		Decrypt_DE();
+		ret = Decrypt_User(0, argv[1]);
+	} else {
+		ret = Decrypt_User(atoi(argv[1]), argv[2]);
+	}
+	if (!ret)
+		printf("Failed to decrypt\n");
+	return 0;
+}