Modest cleanups for DSi_NAND (#1714)

* Add a definition for TMD files

* Wrap TitleMetadata in a namespace

* Add a comment

* Remove TitleMetadataCertificate

- melonDS ignores it anyway

* Refactor the use of title metadata

- Move bitwise operations on the title ID into helper methods
- Use TitleMetadata objects instead of pointers to raw data

* Slight cleanup in DSi_NAND

- Replace some constants with sizeof
- Use an NDSHeader object instead of a raw array of bytes

* Add a DSi_NAND::ImportFile overload that loads a file from memory

* Split most of ImportTitle into InitTitleFileStructure

- It will be reused in the next commit

* Add ability to import title from memory

* Fix another potential issue

* Fix broken DSiWare installation

- The bytes of the title ID/category were being swapped in most places, but not all

* Add some logging calls

* Declare array sizes in DSi_TMD in decimal, not hex

* Add a space after the #endif

- To adhere to the style guide

* Assert the size of TitleMetadataContent

* Change the type of SignatureName

* Don't mark the TMD structs as packed

* Remove extraneous comments

* Cut down some newlines

5 files changed, 254 insertions, 41 deletions

diff --git a/src/DSi_NAND.cpp b/src/DSi_NAND.cpp
index 6af2dd2..6adfcff 100644
--- a/src/DSi_NAND.cpp
+++ b/src/DSi_NAND.cpp
@@ -664,6 +664,40 @@ void debug_listfiles(const char* path)
     f_closedir(&dir);
 }
 
+bool ImportFile(const char* path, const u8* data, size_t len)
+{
+    if (!data || !len || !path)
+        return false;
+
+    FF_FIL file;
+    FRESULT res;
+
+    res = f_open(&file, path, FA_CREATE_ALWAYS | FA_WRITE);
+    if (res != FR_OK)
+    {
+        return false;
+    }
+
+    u8 buf[0x1000];
+    for (u32 i = 0; i < len; i += sizeof(buf))
+    { // For each block in the file...
+        u32 blocklen;
+        if ((i + sizeof(buf)) > len)
+            blocklen = len - i;
+        else
+            blocklen = sizeof(buf);
+
+        u32 nwrite;
+        memcpy(buf, data + i, blocklen);
+        f_write(&file, buf, blocklen, &nwrite);
+    }
+
+    f_close(&file);
+    Log(LogLevel::Debug, "Imported file from memory to %s\n", path);
+
+    return true;
+}
+
 bool ImportFile(const char* path, const char* in)
 {
     FF_FIL file;
@@ -686,13 +720,13 @@ bool ImportFile(const char* path, const char* in)
     }
 
     u8 buf[0x1000];
-    for (u32 i = 0; i < len; i += 0x1000)
+    for (u32 i = 0; i < len; i += sizeof(buf))
     {
         u32 blocklen;
-        if ((i + 0x1000) > len)
+        if ((i + sizeof(buf)) > len)
             blocklen = len - i;
         else
-            blocklen = 0x1000;
+            blocklen = sizeof(buf);
 
         u32 nwrite;
         fread(buf, blocklen, 1, fin);
@@ -702,6 +736,8 @@ bool ImportFile(const char* path, const char* in)
     fclose(fin);
     f_close(&file);
 
+    Log(LogLevel::Debug, "Imported file from %s to %s\n", in, path);
+
     return true;
 }
 
@@ -741,6 +777,8 @@ bool ExportFile(const char* path, const char* out)
     fclose(fout);
     f_close(&file);
 
+    Log(LogLevel::Debug, "Exported file from %s to %s\n", path, out);
+
     return true;
 }
 
@@ -754,6 +792,7 @@ void RemoveFile(const char* path)
         f_chmod(path, 0, AM_RDO);
 
     f_unlink(path);
+    Log(LogLevel::Debug, "Removed file at %s\n", path);
 }
 
 void RemoveDir(const char* path)
@@ -807,6 +846,7 @@ void RemoveDir(const char* path)
     }
 
     f_unlink(path);
+    Log(LogLevel::Debug, "Removed directory at %s\n", path);
 }
 
 
@@ -1049,23 +1089,10 @@ bool CreateSaveFile(const char* path, u32 len)
     return true;
 }
 
-bool ImportTitle(const char* appfile, u8* tmd, bool readonly)
+bool InitTitleFileStructure(const NDSHeader& header, const DSi_TMD::TitleMetadata& tmd, bool readonly)
 {
-    u8 header[0x1000];
-    {
-        FILE* f = fopen(appfile, "rb");
-        if (!f) return false;
-        fread(header, 0x1000, 1, f);
-        fclose(f);
-    }
-
-    u32 version = (tmd[0x1E4] << 24) | (tmd[0x1E5] << 16) | (tmd[0x1E6] << 8) | tmd[0x1E7];
-    Log(LogLevel::Info, ".app version: %08x\n", version);
-
-    u32 titleid0 = (tmd[0x18C] << 24) | (tmd[0x18D] << 16) | (tmd[0x18E] << 8) | tmd[0x18F];
-    u32 titleid1 = (tmd[0x190] << 24) | (tmd[0x191] << 16) | (tmd[0x192] << 8) | tmd[0x193];
-    Log(LogLevel::Info, "Title ID: %08x/%08x\n", titleid0, titleid1);
-
+    u32 titleid0 = tmd.GetCategory();
+    u32 titleid1 = tmd.GetID();
     FRESULT res;
     FF_DIR ticketdir;
     FF_FILINFO info;
@@ -1079,7 +1106,7 @@ bool ImportTitle(const char* appfile, u8* tmd, bool readonly)
     f_mkdir(fname);
 
     sprintf(fname, "0:/ticket/%08x/%08x.tik", titleid0, titleid1);
-    if (!CreateTicket(fname, *(u32*)&tmd[0x18C], *(u32*)&tmd[0x190], header[0x1E]))
+    if (!CreateTicket(fname, tmd.GetCategoryNoByteswap(), tmd.GetIDNoByteswap(), header.ROMVersion))
         return false;
 
     if (readonly) f_chmod(fname, AM_RDO, AM_RDO);
@@ -1098,14 +1125,14 @@ bool ImportTitle(const char* appfile, u8* tmd, bool readonly)
     // data
 
     sprintf(fname, "0:/title/%08x/%08x/data/public.sav", titleid0, titleid1);
-    if (!CreateSaveFile(fname, *(u32*)&header[0x238]))
+    if (!CreateSaveFile(fname, header.DSiPublicSavSize))
         return false;
 
     sprintf(fname, "0:/title/%08x/%08x/data/private.sav", titleid0, titleid1);
-    if (!CreateSaveFile(fname, *(u32*)&header[0x23C]))
+    if (!CreateSaveFile(fname, header.DSiPrivateSavSize))
         return false;
 
-    if (header[0x1BF] & 0x04)
+    if (header.AppFlags & 0x04)
     {
         // custom banner file
         sprintf(fname, "0:/title/%08x/%08x/data/banner.sav", titleid0, titleid1);
@@ -1117,8 +1144,8 @@ bool ImportTitle(const char* appfile, u8* tmd, bool readonly)
         }
 
         u8 bannersav[0x4000];
-        memset(bannersav, 0, 0x4000);
-        f_write(&file, bannersav, 0x4000, &nwrite);
+        memset(bannersav, 0, sizeof(bannersav));
+        f_write(&file, bannersav, sizeof(bannersav), &nwrite);
 
         f_close(&file);
     }
@@ -1133,18 +1160,81 @@ bool ImportTitle(const char* appfile, u8* tmd, bool readonly)
         return false;
     }
 
-    f_write(&file, tmd, 0x208, &nwrite);
+    f_write(&file, &tmd, sizeof(DSi_TMD::TitleMetadata), &nwrite);
 
     f_close(&file);
 
     if (readonly) f_chmod(fname, AM_RDO, AM_RDO);
 
+    return true;
+}
+
+bool ImportTitle(const char* appfile, const DSi_TMD::TitleMetadata& tmd, bool readonly)
+{
+    NDSHeader header {};
+    {
+        FILE* f = fopen(appfile, "rb");
+        if (!f) return false;
+        fread(&header, sizeof(header), 1, f);
+        fclose(f);
+    }
+
+    u32 version = tmd.Contents.GetVersion();
+    Log(LogLevel::Info, ".app version: %08x\n", version);
+
+    u32 titleid0 = tmd.GetCategory();
+    u32 titleid1 = tmd.GetID();
+    Log(LogLevel::Info, "Title ID: %08x/%08x\n", titleid0, titleid1);
+
+    if (!InitTitleFileStructure(header, tmd, readonly))
+    {
+        Log(LogLevel::Error, "ImportTitle: failed to initialize file structure for imported title\n");
+        return false;
+    }
+
     // executable
 
+    char fname[128];
     sprintf(fname, "0:/title/%08x/%08x/content/%08x.app", titleid0, titleid1, version);
     if (!ImportFile(fname, appfile))
     {
-        Log(LogLevel::Error, "ImportTitle: failed to create executable (%d)\n", res);
+        Log(LogLevel::Error, "ImportTitle: failed to create executable\n");
+        return false;
+    }
+
+    if (readonly) f_chmod(fname, AM_RDO, AM_RDO);
+
+    return true;
+}
+
+bool ImportTitle(const u8* app, size_t appLength, const DSi_TMD::TitleMetadata& tmd, bool readonly)
+{
+    if (!app || appLength < sizeof(NDSHeader))
+        return false;
+
+    NDSHeader header {};
+    memcpy(&header, app, sizeof(header));
+
+    u32 version = tmd.Contents.GetVersion();
+    Log(LogLevel::Info, ".app version: %08x\n", version);
+
+    u32 titleid0 = tmd.GetCategory();
+    u32 titleid1 = tmd.GetID();
+    Log(LogLevel::Info, "Title ID: %08x/%08x\n", titleid0, titleid1);
+
+    if (!InitTitleFileStructure(header, tmd, readonly))
+    {
+        Log(LogLevel::Error, "ImportTitle: failed to initialize file structure for imported title\n");
+        return false;
+    }
+
+    // executable
+
+    char fname[128];
+    sprintf(fname, "0:/title/%08x/%08x/content/%08x.app", titleid0, titleid1, version);
+    if (!ImportFile(fname, app, appLength))
+    {
+        Log(LogLevel::Error, "ImportTitle: failed to create executable\n");
         return false;
     }
 
diff --git a/src/DSi_NAND.h b/src/DSi_NAND.h
index a23e62f..76d5ee2 100644
--- a/src/DSi_NAND.h
+++ b/src/DSi_NAND.h
@@ -21,6 +21,7 @@
 
 #include "types.h"
 #include "NDS_Header.h"
+#include "DSi_TMD.h"
 #include <vector>
 #include <string>
 
@@ -49,7 +50,8 @@ void PatchUserData();
 void ListTitles(u32 category, std::vector<u32>& titlelist);
 bool TitleExists(u32 category, u32 titleid);
 void GetTitleInfo(u32 category, u32 titleid, u32& version, NDSHeader* header, NDSBanner* banner);
-bool ImportTitle(const char* appfile, u8* tmd, bool readonly);
+bool ImportTitle(const char* appfile, const DSi_TMD::TitleMetadata& tmd, bool readonly);
+bool ImportTitle(const u8* app, size_t appLength, const DSi_TMD::TitleMetadata& tmd, bool readonly);
 void DeleteTitle(u32 category, u32 titleid);
 
 u32 GetTitleDataMask(u32 category, u32 titleid);
diff --git a/src/DSi_TMD.h b/src/DSi_TMD.h
new file mode 100644
index 0000000..12226c5
--- /dev/null
+++ b/src/DSi_TMD.h
@@ -0,0 +1,119 @@
+/*
+    Copyright 2016-2023 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef DSI_TMD_H
+#define DSI_TMD_H
+
+#include "types.h"
+#include <array>
+
+namespace DSi_TMD
+{
+
+struct TitleMetadataContent {
+    u8 ContentId[4]; /// Content ID (00,00,00,vv) ;lowercase/hex ;"0000000vv.app"
+    u8 ContentIndex[2]; /// Content Index (00,00)
+    u8 ContentType[2]; /// Content Type (00,01) ;aka DSi .app
+    u8 ContentSize[8]; /// Content Size (00,00,00,00,00,19,E4,00)
+    u8 ContentSha1Hash[20]; /// Content SHA1 (on decrypted ".app" file)
+
+    [[nodiscard]] u32 GetVersion() const noexcept
+    {
+        return (ContentId[0] << 24) | (ContentId[1] << 16) | (ContentId[2] << 8) | ContentId[3];
+    }
+};
+
+static_assert(sizeof(TitleMetadataContent) == 36, "TitleMetadataContent is not 36 bytes!");
+
+/// Metadata for a DSiWare title.
+/// Used to install DSiWare titles to NAND.
+/// @see https://problemkaputt.de/gbatek.htm#dsisdmmcdsiwareticketsandtitlemetadata
+struct TitleMetadata
+{
+    u32 SignatureType;
+    u8 Signature[256];
+    u8 SignatureAlignment[60];
+    char SignatureName[64];
+
+    u8 TmdVersion;
+    u8 CaCrlVersion;
+    u8 SignerCrlVersion;
+    u8 Padding0;
+
+    u8 SystemVersion[8];
+    u8 TitleId[8];
+    u32 TitleType;
+    u8 GroupId[2];
+    u8 PublicSaveSize[4];
+    u8 PrivateSaveSize[4];
+    u8 Padding1[4];
+
+    u8 SrlFlag;
+    u8 Padding2[3];
+
+    u8 AgeRatings[16];
+    u8 Padding3[30];
+
+    u32 AccessRights;
+    u16 TitleVersion;
+
+    u16 NumberOfContents; /// There's always one or zero content entries in practice
+    u16 BootContentIndex;
+    u8 Padding4[2];
+
+    TitleMetadataContent Contents;
+
+    [[nodiscard]] bool HasPublicSaveData() const noexcept { return GetPublicSaveSize() != 0; }
+    [[nodiscard]] bool HasPrivateSaveData() const noexcept { return GetPrivateSaveSize() != 0; }
+
+    [[nodiscard]] u32 GetPublicSaveSize() const noexcept
+    {
+        return (PublicSaveSize[0] << 24) | (PublicSaveSize[1] << 16) | (PublicSaveSize[2] << 8) | PublicSaveSize[3];
+    }
+
+    [[nodiscard]] u32 GetPrivateSaveSize() const noexcept
+    {
+        return (PrivateSaveSize[0] << 24) | (PrivateSaveSize[1] << 16) | (PrivateSaveSize[2] << 8) | PrivateSaveSize[3];
+    }
+
+    [[nodiscard]] u32 GetCategory() const noexcept
+    {
+       return (TitleId[0] << 24) | (TitleId[1] << 16) | (TitleId[2] << 8) | TitleId[3];
+    }
+
+    [[nodiscard]] u32 GetCategoryNoByteswap() const noexcept
+    {
+        return reinterpret_cast<const u32&>(TitleId);
+    }
+
+    [[nodiscard]] u32 GetID() const noexcept
+    {
+        return (TitleId[4] << 24) | (TitleId[5] << 16) | (TitleId[6] << 8) | TitleId[7];
+    }
+
+    [[nodiscard]] u32 GetIDNoByteswap() const noexcept
+    {
+        return *reinterpret_cast<const u32*>(&TitleId[4]);
+    }
+};
+
+static_assert(sizeof(TitleMetadata) == 520, "TitleMetadata is not 520 bytes!");
+
+}
+
+#endif // DSI_TMD_H
diff --git a/src/frontend/qt_sdl/TitleManagerDialog.cpp b/src/frontend/qt_sdl/TitleManagerDialog.cpp
index 72d19ec..3d52bdd 100644
--- a/src/frontend/qt_sdl/TitleManagerDialog.cpp
+++ b/src/frontend/qt_sdl/TitleManagerDialog.cpp
@@ -176,7 +176,7 @@ void TitleManagerDialog::done(int r)
 
 void TitleManagerDialog::on_btnImportTitle_clicked()
 {
-    TitleImportDialog* importdlg = new TitleImportDialog(this, importAppPath, importTmdData, importReadOnly);
+    TitleImportDialog* importdlg = new TitleImportDialog(this, importAppPath, &importTmdData, importReadOnly);
     importdlg->open();
     connect(importdlg, &TitleImportDialog::finished, this, &TitleManagerDialog::onImportTitleFinished);
 
@@ -188,8 +188,8 @@ void TitleManagerDialog::onImportTitleFinished(int res)
     if (res != QDialog::Accepted) return;
 
     u32 titleid[2];
-    titleid[0] = (importTmdData[0x18C] << 24) | (importTmdData[0x18D] << 16) | (importTmdData[0x18E] << 8) | importTmdData[0x18F];
-    titleid[1] = (importTmdData[0x190] << 24) | (importTmdData[0x191] << 16) | (importTmdData[0x192] << 8) | importTmdData[0x193];
+    titleid[0] = importTmdData.GetCategory();
+    titleid[1] = importTmdData.GetID();
 
     // remove anything that might hinder the install
     DSi_NAND::DeleteTitle(titleid[0], titleid[1]);
@@ -381,7 +381,7 @@ void TitleManagerDialog::onExportTitleData()
 }
 
 
-TitleImportDialog::TitleImportDialog(QWidget* parent, QString& apppath, u8* tmd, bool& readonly)
+TitleImportDialog::TitleImportDialog(QWidget* parent, QString& apppath, const DSi_TMD::TitleMetadata* tmd, bool& readonly)
 : QDialog(parent), ui(new Ui::TitleImportDialog), appPath(apppath), tmdData(tmd), readOnly(readonly)
 {
     ui->setupUi(this);
@@ -440,12 +440,12 @@ void TitleImportDialog::accept()
             return;
         }
 
-        fread(tmdData, 0x208, 1, f);
+        fread((void *) tmdData, sizeof(DSi_TMD::TitleMetadata), 1, f);
         fclose(f);
 
         u32 tmdtitleid[2];
-        tmdtitleid[0] = (tmdData[0x18C] << 24) | (tmdData[0x18D] << 16) | (tmdData[0x18E] << 8) | tmdData[0x18F];
-        tmdtitleid[1] = (tmdData[0x190] << 24) | (tmdData[0x191] << 16) | (tmdData[0x192] << 8) | tmdData[0x193];
+        tmdtitleid[0] = tmdData->GetCategory();
+        tmdtitleid[1] = tmdData->GetID();
 
         if (tmdtitleid[1] != titleid[0] || tmdtitleid[0] != titleid[1])
         {
@@ -507,11 +507,11 @@ void TitleImportDialog::tmdDownloaded()
     }
     else
     {
-        netreply->read((char*)tmdData, 520);
+        netreply->read((char*)tmdData, sizeof(*tmdData));
 
         u32 tmdtitleid[2];
-        tmdtitleid[0] = (tmdData[0x18C] << 24) | (tmdData[0x18D] << 16) | (tmdData[0x18E] << 8) | tmdData[0x18F];
-        tmdtitleid[1] = (tmdData[0x190] << 24) | (tmdData[0x191] << 16) | (tmdData[0x192] << 8) | tmdData[0x193];
+        tmdtitleid[0] = tmdData->GetCategory();
+        tmdtitleid[1] = tmdData->GetID();
 
         if (tmdtitleid[1] != titleid[0] || tmdtitleid[0] != titleid[1])
         {
diff --git a/src/frontend/qt_sdl/TitleManagerDialog.h b/src/frontend/qt_sdl/TitleManagerDialog.h
index cba7047..fc92fd8 100644
--- a/src/frontend/qt_sdl/TitleManagerDialog.h
+++ b/src/frontend/qt_sdl/TitleManagerDialog.h
@@ -29,6 +29,8 @@
 #include <QNetworkReply>
 #include <QNetworkAccessManager>
 
+#include "DSi_TMD.h"
+
 namespace Ui
 {
     class TitleManagerDialog;
@@ -90,7 +92,7 @@ private:
     Ui::TitleManagerDialog* ui;
 
     QString importAppPath;
-    u8 importTmdData[0x208];
+    DSi_TMD::TitleMetadata importTmdData;
     bool importReadOnly;
 
     QAction* actImportTitleData[3];
@@ -104,7 +106,7 @@ class TitleImportDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit TitleImportDialog(QWidget* parent, QString& apppath, u8* tmd, bool& readonly);
+    explicit TitleImportDialog(QWidget* parent, QString& apppath, const DSi_TMD::TitleMetadata* tmd, bool& readonly);
     ~TitleImportDialog();
 
 private slots:
@@ -124,7 +126,7 @@ private:
     QNetworkReply* netreply;
 
     QString& appPath;
-    u8* tmdData;
+    const DSi_TMD::TitleMetadata* tmdData;
     bool& readOnly;
 
     u32 titleid[2];