src/fileio.c

// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <efi.h>
#include <efilib.h>
#include <utils.h>

EFI_STATUS efi_main(EFI_HANDLE img, EFI_SYSTEM_TABLE* sys) {
    EFI_LOADED_IMAGE* loaded;
    EFI_STATUS r;

    InitializeLib(img, sys);
    InitGoodies(img, sys);

    Print(L"Hello, EFI World\n");

    r = OpenProtocol(img, &LoadedImageProtocol, (void**)&loaded);
    if (r)
        Fatal("LoadedImageProtocol", r);

    Print(L"Img DeviceHandle='%s'\n", HandleToString(loaded->DeviceHandle));
    Print(L"Img FilePath='%s'\n", DevicePathToStr(loaded->FilePath));
    Print(L"Img Base=%lx Size=%lx\n", loaded->ImageBase, loaded->ImageSize);

    EFI_FILE_IO_INTERFACE* fioi;
    r = OpenProtocol(loaded->DeviceHandle, &SimpleFileSystemProtocol, (void**)&fioi);
    if (r)
        Fatal("SimpleFileSystemProtocol", r);

    EFI_FILE_HANDLE root;
    r = fioi->OpenVolume(fioi, &root);
    if (r)
        Fatal("OpenVolume", r);

    EFI_FILE_HANDLE file;
    r = root->Open(root, &file, L"README.txt", EFI_FILE_MODE_READ, 0);

    if (r == EFI_SUCCESS) {
        char buf[512];
        UINTN sz = sizeof(buf);
        EFI_FILE_INFO* finfo = (void*)buf;
        r = file->GetInfo(file, &FileInfoGUID, &sz, finfo);
        if (r)
            Fatal("GetInfo", r);
        Print(L"FileSize %ld\n", finfo->FileSize);

        sz = sizeof(buf) - 1;
        r = file->Read(file, &sz, buf);
        if (r)
            Fatal("Read", r);

        char* x = buf;
        while (sz-- > 0)
            Print(L"%c", (CHAR16)*x++);

        file->Close(file);
    }

    root->Close(root);
    CloseProtocol(loaded->DeviceHandle, &SimpleFileSystemProtocol);
    CloseProtocol(img, &LoadedImageProtocol);

    WaitAnyKey();

    return EFI_SUCCESS;
}