From 8cf1132b2e1f4a09176801cc2d97b646b3d2bf88 Mon Sep 17 00:00:00 2001
From: zhupengfei <zhupengfei321@sina.cn>
Date: Mon, 1 Oct 2018 08:41:40 +0800
Subject: [PATCH] ncch_container: choose the first id as extdata id when
 extended save data access is used

---
 src/core/file_sys/ncch_container.cpp | 20 +++++++++++++++++++-
 src/core/file_sys/ncch_container.h   | 18 ++++++++++++++++--
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/src/core/file_sys/ncch_container.cpp b/src/core/file_sys/ncch_container.cpp
index e817a004f..fbda4ba80 100644
--- a/src/core/file_sys/ncch_container.cpp
+++ b/src/core/file_sys/ncch_container.cpp
@@ -585,7 +585,25 @@ Loader::ResultStatus NCCHContainer::ReadExtdataId(u64& extdata_id) {
         return Loader::ResultStatus::ErrorNotUsed;
 
     if (exheader_header.arm11_system_local_caps.storage_info.other_attributes >> 1) {
-        // Extdata id is not present when using extended savedata access
+        // Using extended save data access
+        // There would be multiple possible extdata IDs in this case. The best we can do for now is
+        // guessing that the first one would be the main save.
+        const std::array<u64, 6> extdata_ids{{
+            exheader_header.arm11_system_local_caps.storage_info.extdata_id0.Value(),
+            exheader_header.arm11_system_local_caps.storage_info.extdata_id1.Value(),
+            exheader_header.arm11_system_local_caps.storage_info.extdata_id2.Value(),
+            exheader_header.arm11_system_local_caps.storage_info.extdata_id3.Value(),
+            exheader_header.arm11_system_local_caps.storage_info.extdata_id4.Value(),
+            exheader_header.arm11_system_local_caps.storage_info.extdata_id5.Value(),
+        }};
+        for (u64 id : extdata_ids) {
+            if (id) {
+                // Found a non-zero ID, use it
+                extdata_id = id;
+                return Loader::ResultStatus::Success;
+            }
+        }
+
         return Loader::ResultStatus::ErrorNotUsed;
     }
 
diff --git a/src/core/file_sys/ncch_container.h b/src/core/file_sys/ncch_container.h
index bee740e3b..79f87a6ef 100644
--- a/src/core/file_sys/ncch_container.h
+++ b/src/core/file_sys/ncch_container.h
@@ -125,9 +125,23 @@ struct ExHeader_SystemInfo {
 };
 
 struct ExHeader_StorageInfo {
-    u64_le ext_save_data_id;
+    union {
+        u64_le ext_save_data_id;
+        // When using extended savedata access
+        // Prefer the ID specified in the most significant bits
+        BitField<40, 20, u64_le> extdata_id3;
+        BitField<20, 20, u64_le> extdata_id4;
+        BitField<0, 20, u64_le> extdata_id5;
+    };
     u8 system_save_data_id[8];
-    u8 reserved[8];
+    union {
+        u64_le storage_accessible_unique_ids;
+        // When using extended savedata access
+        // Prefer the ID specified in the most significant bits
+        BitField<40, 20, u64_le> extdata_id0;
+        BitField<20, 20, u64_le> extdata_id1;
+        BitField<0, 20, u64_le> extdata_id2;
+    };
     u8 access_info[7];
     u8 other_attributes;
 };