gistfile1.diff

diff --git a/src/core/hle/service/cfg_u.cpp b/src/core/hle/service/cfg_u.cpp
index 2e9d7bf..6c2323a 100644
--- a/src/core/hle/service/cfg_u.cpp
+++ b/src/core/hle/service/cfg_u.cpp
@@ -2,7 +2,9 @@
 // Licensed under GPLv2
 // Refer to the license.txt file included.
 
+#include "common/file_util.h"
 #include "common/log.h"
+#include "core/file_sys/archive_systemsavedata.h"
 #include "core/hle/hle.h"
 #include "core/hle/service/cfg_u.h"
 
@@ -11,6 +13,11 @@
 
 namespace CFG_U {
 
+static FileSys::Archive_SystemSaveData* cfg_system_save_data = nullptr;
+static const u64 CFG_SAVE_ID = 0x00010017;
+static const u64 CONSOLE_UNIQUE_ID = 0xDEADC0DE;
+static const char CONSOLE_USERNAME[0x1C] = "THIS IS CITRAAAAAAAAAAAAAA";
+
 // TODO(Link Mauve): use a constexpr once MSVC starts supporting it.
 #define C(code) ((code)[0] | ((code)[1] << 8))
 
@@ -99,8 +106,86 @@ static void GetCountryCodeID(Service::Interface* self) {
     cmd_buffer[2] = country_code_id;
 }
 
+/// Block header in the config savedata file
+struct SaveConfigBlockEntry {
+    u32 block_id;
+    u32 offset_or_data;
+    u16 size;
+    u16 flags;
+};
+
+/// The header of the config savedata file,
+/// contains information about the blocks in the file
+struct SaveFileConfig {
+    u16 total_entries;
+    u16 data_entries_offset;
+    SaveConfigBlockEntry block_entries[1479];
+};
+
+/* Reads a block with the specified id and flag from the Config savegame file and writes the output to output.
+ * The input size must match exactly the size of the requested block
+ * TODO(Subv): This should actually be in some file common to the CFG process
+ * @param block_id The id of the block we want to read
+ * @param size The size of the block we want to read
+ * @param flag The requested block must have this flag set
+ * @param output A pointer where we will write the read data
+ * @returns ResultCode indicating the result of the operation, 0 on success
+ */
+ResultCode GetConfigInfoBlock(u32 block_id, u32 size, u32 flag, u8* output) {
+    FileSys::Mode mode;
+    mode.hex = 0;
+    mode.read_flag = 1;
+    FileSys::Path path("config");
+    auto file = cfg_system_save_data->OpenFile(path, mode);
+    _dbg_assert_msg_(Service_CFG, file != nullptr, "Could not open the CFG service config file");
+    SaveFileConfig config;
+    size_t read = file->Read(0, sizeof(SaveFileConfig), reinterpret_cast<u8*>(&config));
+    
+    if (read != sizeof(SaveFileConfig)) {
+        LOG_CRITICAL(Service_CFG, "The config savefile is corrupted");
+        return ResultCode(-1); // TODO(Subv): Find the correct error code
+    }
+
+    auto itr = std::find_if(std::begin(config.block_entries), std::end(config.block_entries), 
+        [&](SaveConfigBlockEntry const& entry) {
+            return entry.block_id == block_id && entry.size == size && (entry.flags & flag);
+    });
+
+    if (itr == std::end(config.block_entries)) {
+        LOG_TRACE(Service_CFG, "Config block %u with size %u and flags %u not found", block_id, size, flag);
+        return ResultCode(-1); // TODO(Subv): Find the correct error code
+    }
+
+    // The data is located in the block header itself if the size is less than 4 bytes
+    if (itr->size <= 4) {
+        memcpy(output, &itr->offset_or_data, itr->size);
+    } else {
+        size_t data_read = file->Read(itr->offset_or_data, itr->size, output);
+        if (data_read != itr->size) {
+            LOG_CRITICAL(Service_CFG, "The config savefile is corrupted");
+            return ResultCode(-1); // TODO(Subv): Find the correct error code
+        }
+    }
+
+    return RESULT_SUCCESS;
+}
+
+static void GetConfigInfoBlk2(Service::Interface* self) {
+    u32* cmd_buffer = Kernel::GetCommandBuffer();
+    u32 size = cmd_buffer[1];
+    u32 block_id = cmd_buffer[2];
+    u8* data_pointer = Memory::GetPointer(cmd_buffer[4]);
+    
+    if (data_pointer == nullptr) {
+        cmd_buffer[1] = -1; // TODO(Subv): Find the right error code
+        return;
+    }
+
+    cmd_buffer[1] = GetConfigInfoBlock(block_id, size, 0x2, data_pointer).raw;
+}
+
 const Interface::FunctionInfo FunctionTable[] = {
-    {0x00010082, nullptr,               "GetConfigInfoBlk2"},
+    {0x00010082, GetConfigInfoBlk2,     "GetConfigInfoBlk2"},
     {0x00020000, nullptr,               "SecureInfoGetRegion"},
     {0x00030000, nullptr,               "GenHashConsoleUnique"},
     {0x00040000, nullptr,               "GetRegionCanadaUSA"},
@@ -116,9 +201,51 @@ const Interface::FunctionInfo FunctionTable[] = {
 
 Interface::Interface() {
     Register(FunctionTable, ARRAY_SIZE(FunctionTable));
+    // TODO(Subv): In the future we should use the FS service to query this archive, 
+    // currently it is not possible because you can only have one open archive of the same type at any time
+    std::string syssavedata_directory = FileUtil::GetUserPath(D_SYSSAVEDATA_IDX);
+    cfg_system_save_data = new FileSys::Archive_SystemSaveData(syssavedata_directory, CFG_SAVE_ID);
+    if (!cfg_system_save_data->Initialize()) {
+        LOG_CRITICAL(Service_CFG, "Could not initialize SystemSaveData archive for the CFG:U service");
+    } else {
+        // Try to open the file in read-only mode to check its existence
+        FileSys::Mode mode;
+        mode.hex = 0;
+        mode.read_flag = 1;
+        FileSys::Path path("config");
+        auto file = cfg_system_save_data->OpenFile(path, mode);
+        if (file == nullptr) {
+            mode.create_flag = 1;
+            mode.write_flag = 1;
+            mode.read_flag = 0;
+            // Re-open the file in write-create mode
+            file = cfg_system_save_data->OpenFile(path, mode);
+
+            // Setup the default config file data header
+            SaveFileConfig config = { 3, 0, {} };
+            u32 offset = sizeof(SaveFileConfig);
+            // Console-unique ID
+            config.block_entries[0] = { 0x00090001, offset, 0x8, 0xE };
+            offset += 0x8;
+            // Username
+            config.block_entries[1] = { 0x000A0000, offset, 0x1C, 0xE };
+            offset += 0x1C;
+            // System Model (Nintendo 3DS XL)
+            config.block_entries[2] = { 0x000F0004, 1, 0x4, 0x8 };
+
+            // Write the config file data header to the config file
+            file->Write(0, sizeof(SaveFileConfig), 1, reinterpret_cast<u8*>(&config));
+            // Write the data itself
+            file->Write(config.block_entries[0].offset_or_data, 0x8, 1, 
+                reinterpret_cast<u8 const*>(&CONSOLE_UNIQUE_ID));
+            file->Write(config.block_entries[1].offset_or_data, 0x1C, 1, 
+                reinterpret_cast<u8 const*>(CONSOLE_USERNAME));
+        }
+    }
 }
 
 Interface::~Interface() {
+    delete cfg_system_save_data;
 }
 
 } // namespace