Add file functionality in fs.cpp

src/boot/fs.cpp

@@ -0,0 +1,65 @@
+#include <uefi/types.h>
+#include <uefi/protos/loaded_image.h>
+#include <uefi/protos/simple_file_system.h>
+
+#include "fs.h"
+#include "console.h"
+#include "error.h"
+
+namespace boot {
+namespace fs {
+
+file::file(uefi::protos::file *f) :
+	m_file(f)
+{
+}
+
+file::file(file &&o) :
+	m_file(o.m_file)
+{
+	o.m_file = nullptr;
+}
+
+file
+file::open(const wchar_t *path)
+{
+	uefi::protos::file *fh = nullptr;
+
+	try_or_raise(
+		m_file->open(&fh, path, uefi::file_mode::read, uefi::file_attr::none),
+		L"Could not open relative path to file");
+
+	return file(fh);
+}
+
+file
+get_boot_volume(uefi::handle image, uefi::boot_services *bs)
+{
+	status_line status(L"Looking up boot volume");
+
+	const uefi::guid le_guid = uefi::protos::loaded_image::guid;
+	uefi::protos::loaded_image *loaded_image = nullptr;
+
+	try_or_raise(
+		bs->handle_protocol(image, &le_guid,
+			reinterpret_cast<void**>(&loaded_image)),
+		L"Could not find currently running UEFI loaded image");
+
+	const uefi::guid sfs_guid = uefi::protos::simple_file_system::guid;
+	uefi::protos::simple_file_system *fs;
+	try_or_raise(
+		bs->handle_protocol(loaded_image->device_handle, &sfs_guid,
+			reinterpret_cast<void**>(&fs)),
+		L"Could not find filesystem protocol for boot volume");
+
+	uefi::protos::file *f;
+	try_or_raise(
+		fs->open_volume(&f),
+		L"Could not open the boot volume");
+
+	return file(f);
+}
+
+} // namespace fs
+} // namespace boot
+