Kernel: Move devices into Kernel/Devices/.

Kernel/Devices/FileBackedDiskDevice.cpp

@@ -0,0 +1,82 @@
+#define _FILE_OFFSET_BITS 64
+
+#include <Kernel/Devices/FileBackedDiskDevice.h>
+#include <cstring>
+#include <sys/stat.h>
+
+//#define FBBD_DEBUG
+#define IGNORE_FILE_LENGTH // Useful for e.g /dev/hda2
+
+RetainPtr<FileBackedDiskDevice> FileBackedDiskDevice::create(String&& image_path, unsigned block_size)
+{
+    return adopt(*new FileBackedDiskDevice(move(image_path), block_size));
+}
+
+FileBackedDiskDevice::FileBackedDiskDevice(String&& image_path, unsigned block_size)
+    : m_image_path(move(image_path))
+    , m_block_size(block_size)
+{
+    struct stat st;
+    int result = stat(m_image_path.characters(), &st);
+    ASSERT(result != -1);
+    m_file_length = st.st_size;
+    m_file = fopen(m_image_path.characters(), "r+");
+}
+
+FileBackedDiskDevice::~FileBackedDiskDevice()
+{
+}
+
+unsigned FileBackedDiskDevice::block_size() const
+{
+    return m_block_size;
+}
+
+bool FileBackedDiskDevice::read_block(unsigned index, byte* out) const
+{
+    DiskOffset offset = index * m_block_size;
+    return read_internal(offset, block_size(), out);
+}
+
+bool FileBackedDiskDevice::write_block(unsigned index, const byte* data)
+{
+    DiskOffset offset = index * m_block_size;
+    return write_internal(offset, block_size(), data);
+}
+
+bool FileBackedDiskDevice::read_internal(DiskOffset offset, unsigned length, byte* out) const
+{
+#ifndef IGNORE_FILE_LENGTH
+    if (offset + length >= m_file_length)
+        return false;
+#endif
+#ifdef FBBD_DEBUG
+    printf("[FileBackedDiskDevice] Read device @ offset %llx, length %u\n", offset, length);
+#endif
+    fseeko(m_file, offset, SEEK_SET);
+    unsigned nread = fread(out, sizeof(byte), length, m_file);
+    ASSERT(nread == length);
+    return true;
+}
+
+bool FileBackedDiskDevice::write_internal(DiskOffset offset, unsigned length, const byte* data)
+{
+#ifndef IGNORE_FILE_LENGTH
+    if (offset + length >= m_file_length)
+        return false;
+#endif
+#ifdef FBBD_DEBUG
+    printf("[FileBackedDiskDevice] Write device @ offset %llx, length %u\n", offset, length);
+#endif
+    fseeko(m_file, offset, SEEK_SET);
+    // size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
+    unsigned nwritten = fwrite(data, sizeof(byte), length, m_file);
+    ASSERT(nwritten == length);
+    return true;
+}
+
+const char* FileBackedDiskDevice::class_name() const
+{
+    return "FileBackedDiskDevice";
+}
+