Implement reading from RomFS

src/core/filesystem/archive_ncch.cpp

@@ -0,0 +1,62 @@
+#include "fs/archive_ncch.hpp"
+#include <memory>
+
+bool SelfNCCHArchive::openFile(const FSPath& path) {
+	if (path.type != PathType::Binary) {
+		printf("Invalid SelfNCCH path type");
+		return false;
+	}
+
+	// We currently only know how to read from an NCCH's RomFS
+	if (mem.read32(path.pointer) != 0) {
+		Helpers::panic("Read from NCCH's non-RomFS section!");
+	}
+
+	return true;
+}
+
+ArchiveBase* SelfNCCHArchive::openArchive(FSPath& path) {
+	if (path.type != PathType::Empty) {
+		printf("Invalid path type for SelfNCCH archive: %d\n", path.type);
+		return nullptr;
+	}
+
+	return this;
+}
+
+std::optional<u32> SelfNCCHArchive::readFile(FileSession* file, u64 offset, u32 size, u32 dataPointer) {
+	auto cxi = mem.getCXI();
+	if (cxi == nullptr) {
+		Helpers::panic("Tried to read file from non-existent CXI");
+		return std::nullopt;
+	}
+
+	if (!cxi->hasRomFS()) {
+		Helpers::panic("Tried to read from CXI without RomFS");
+	}
+
+	const u32 romFSSize = cxi->romFS.size;
+	const u32 romFSOffset = cxi->romFS.offset;
+	if ((offset >> 32) || (offset >= romFSSize) || (offset + size >= romFSSize)) {
+		Helpers::panic("Tried to read from SelfNCCH with too big of an offset");
+	}
+
+	IOFile& ioFile = mem.CXIFile;
+	if (!ioFile.seek(cxi->fileOffset + romFSOffset + offset)) {
+		Helpers::panic("Failed to seek while reading from RomFS");
+	}
+
+	std::unique_ptr<u8[]> data(new u8[size]);
+	auto [success, bytesRead] = ioFile.readBytes(&data[0], size);
+
+	if (!success) {
+		Helpers::panic("Failed to read from RomFS");
+	}
+
+	for (u64 i = 0; i < bytesRead; i++) {
+		mem.write8(dataPointer + i, data[i]);
+		printf("%x\n", data[i]);
+	}
+
+	return bytesRead;
+}

src/core/kernel/file_operations.cpp

@@ -2,17 +2,64 @@
 
 namespace FileOps {
 	enum : u32 {
-		Read = 0x080200C2
+		Read = 0x080200C2,
+		Close = 0x08080000
 	};
 }
 
+namespace Result {
+	enum : u32 {
+		Success = 0
+	};
+}
+
+
 void Kernel::handleFileOperation(u32 messagePointer, Handle file) {
 	const u32 cmd = mem.read32(messagePointer);
 	switch (cmd) {
+		case FileOps::Close: closeFile(messagePointer, file); break;
+		case FileOps::Read: readFile(messagePointer, file); break;
 		default: Helpers::panic("Unknown file operation: %08X", cmd);
 	}
 }
 
-void Kernel::readFile(u32 messagePointer, Handle file) {
-	
+void Kernel::closeFile(u32 messagePointer, Handle fileHandle) {
+	logFileIO("Closed file %X\n", fileHandle);
+
+	const auto p = getObject(fileHandle, KernelObjectType::File);
+	if (p == nullptr) [[unlikely]] {
+		Helpers::panic("Called CloseFile on non-existent file");
+	}
+
+	p->getData<FileSession>()->isOpen = false;
+	mem.write32(messagePointer + 4, Result::Success);
+}
+
+void Kernel::readFile(u32 messagePointer, Handle fileHandle) {
+	u64 offset = mem.read64(messagePointer + 4);
+	u32 size = mem.read32(messagePointer + 12);
+	u32 dataPointer = mem.read32(messagePointer + 20);
+
+	logFileIO("Trying to read %X bytes from file %X, starting from offset %llX into memory address %08X\n",
+		size, fileHandle, offset, dataPointer);
+
+	const auto p = getObject(fileHandle, KernelObjectType::File);
+	if (p == nullptr) [[unlikely]] {
+		Helpers::panic("Called ReadFile on non-existent file");
+	}
+
+	FileSession* file = p->getData<FileSession>();
+	if (!file->isOpen) {
+		Helpers::panic("Tried to read closed file");
+	}
+
+	auto archive = file->archive;
+
+	std::optional<u32> bytesRead = archive->readFile(file, offset, size, dataPointer);
+	if (!bytesRead.has_value()) {
+		Helpers::panic("Kernel::ReadFile failed");
+	} else {
+		mem.write32(messagePointer + 4, Result::Success);
+		mem.write32(messagePointer + 8, bytesRead.value());
+	}
 }

src/core/loader/ncsd.cpp

@@ -118,5 +118,9 @@ std::optional<NCSD> Memory::loadNCSD(const std::filesystem::path& path) {
 
     ncsd.entrypoint = textAddr;
 
+    // Back the IOFile for accessing the ROM, as well as the ROM's CXI partition, in the memory class.
+    CXIFile = ncsd.file;
+    loadedCXI = cxi;
+
     return ncsd;
 }