content: /* ###
   * IP: GHIDRA
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package firmware.uefi_fv;
  
  import java.io.IOException;
  import java.util.UUID;
  
  import firmware.common.UUIDUtils;
  import ghidra.app.util.bin.BinaryReader;
  import ghidra.formats.gfilesystem.FileSystemIndexHelper;
  import ghidra.formats.gfilesystem.GFile;
  import ghidra.formats.gfilesystem.fileinfo.FileAttributeType;
  import ghidra.formats.gfilesystem.fileinfo.FileAttributes;
  import ghidra.util.Msg;
  
  /**
   * Parser for UEFI Firmware File System (FFS) files, which have the following header:
   *
   *   UEFI FFS File Header
   *   +------------+------+----------------------------------------+
   *   | Type       | Size | Description                            |
   *   +------------+------+----------------------------------------+
   *   | efi_guid_t |   16 | File GUID                              |
   *   | u8         |    1 | Header Checksum                        |
   *   | u8         |    1 | File Checksum                          |
   *   | u8         |    1 | Type                                   |
   *   | u8         |    1 | Attributes                             |
   *   | u24        |    3 | Size (0xFFFFFF for FFSv3 large files)  |
   *   | u8         |    1 | State                                  |
   *   | u64        |    8 | Extended Size (FFSv3 large files only) |
   *   +------------+------+----------------------------------------+
   *
   * FFSv3 files can be identified by checking if FFS_ATTRIB_LARGE_FILE (0x01) is set in the
   * Attributes field.
   *
   * Following the header, FFS files may contain multiple sections (this does not apply for raw FFS
   * files). See FFSSection for information regarding the common FFS section header, as well as
   * UEFIFFSConstants.FileType for possible FFS file Type values.
   */
  public class UEFIFFSFile implements UEFIFile {
  	// Original header fields
  	private final UUID nameGuid;
  	private final byte headerChecksum;
  	private final byte fileChecksum;
  	private final byte type;
  	private final byte attributes;
  	private long size;
  	private final byte state;
  
  	private final long baseIndex;
  	private String uiName;
  
  	/**
  	 * Constructs a UEFIFFSFile from a specified BinaryReader and adds it to a
  	 * specified FileSystemIndexHelper.
  	 *
  	 * @param reader the specified BinaryReader
  	 * @param fsih   the specified {@link FileSystemIndexHelper} that handles files
  	 * @param parent the parent directory in the specified FileSystemIndexHelper
  	 */
  	public UEFIFFSFile(BinaryReader reader, FileSystemIndexHelper<UEFIFile> fsih, GFile parent) throws IOException {
  		baseIndex = reader.getPointerIndex();
  		nameGuid = UUIDUtils.fromBinaryReader(reader);
  		headerChecksum = reader.readNextByte();
  		fileChecksum = reader.readNextByte();
  		type = reader.readNextByte();
  		attributes = reader.readNextByte();
  
  		byte[] sizeBytes = reader.readNextByteArray(3);
  		size = ((sizeBytes[2] & 0xFF) << 16 | (sizeBytes[1] & 0xFF) << 8 | sizeBytes[0] & 0xFF);
  		if (size < UEFIFFSConstants.FFS_HEADER_SIZE) {
  			throw new IOException("Not a valid FFS file");
  		}
  
  		state = reader.readNextByte();
  
  		// Ignore padding files.
  		if (type == UEFIFFSConstants.FileType.PAD) {
  			Msg.debug(this, "Skipping padding file");
  			reader.setPointerIndex(baseIndex + size);
  			return;
  		}
  
  		// Ignore obviously invalid sections (free space).
  		if (nameGuid.equals(UUID.fromString("ffffffff-ffff-ffff-ffff-ffffffffffff")) ||
  				nameGuid.equals(UUID.fromString("00000000-0000-0000-0000-000000000000"))) {
  			throw new IOException("Not a valid FFS file");
  		}
  
  		// Read the extended size for FFSv3 files.
  		if ((attributes & UEFIFFSConstants.Attributes.LARGE_FILE) != 0) {
  			size = reader.readNextLong();
  		}
  
  		// Check if there is a UI section containing a name for this file.
  		// This has to be done before the GFile for this FFS file is created, as the GFile's name
  		// cannot be changed after it is constructed.
  		if (type != UEFIFFSConstants.FileType.RAW) {
  			long currentIndex = reader.getPointerIndex();
  			long remainingLength = size - UEFIFFSConstants.FFS_HEADER_SIZE;
  			while (remainingLength > UEFIFFSConstants.FFS_SECTION_HEADER_SIZE) {
  				FFSSection section = FFSSectionFactory.parseSection(reader);
  				if (section.getType() == UEFIFFSConstants.SectionType.USER_INTERFACE) {
  					uiName = ((FFSUISection) section).getText();
  					break;
  				}
  
  				long unalignedIndex = reader.getPointerIndex();
  				reader.align(4);
  				long alignedIndex = reader.getPointerIndex();
  				remainingLength -= section.getTotalLength() + (alignedIndex - unalignedIndex);
  			}
  
  			reader.setPointerIndex(currentIndex);
  		}
  
  		// Add this file to the current FS.
  		GFile fileImpl = fsih.storeFileWithParent(UEFIFirmwareVolumeFileSystem.getFSFormattedName(this, parent, fsih),
  				parent, -1, true, -1, this);
  
  		long remainingLength = size - UEFIFFSConstants.FFS_HEADER_SIZE;
  		if (type == UEFIFFSConstants.FileType.RAW) {
  			long fvEndIndex = reader.getPointerIndex();
  			long ffsEndIndex = reader.getPointerIndex() + remainingLength;
  			while (remainingLength > UEFIFFSConstants.FFS_SECTION_HEADER_SIZE) {
  				// Raw sections may contain nested firmware volumes.
  				long currentIndex = reader.getPointerIndex();
  				try {
  					UEFIFirmwareVolumeHeader fvh = new UEFIFirmwareVolumeHeader(reader, fsih, fileImpl, true);
  					remainingLength -= fvh.length();
  					fvEndIndex += fvh.length();
  				} catch (IOException e) {
  					reader.setPointerIndex(currentIndex + 1);
  					remainingLength--;
  				}
  			}
  
  			if (fvEndIndex < ffsEndIndex) {
  				reader.setPointerIndex(fvEndIndex);
  				new FFSRawFile(reader, (int) (ffsEndIndex - fvEndIndex), fsih, fileImpl);
  			}
  		} else {
  			// Parse and add each section to the FS.
  			while (remainingLength > UEFIFFSConstants.FFS_SECTION_HEADER_SIZE) {
  				FFSSection section = FFSSectionFactory.parseSection(reader, fsih, fileImpl);
  				// FFS sections are aligned to a 4 byte boundary.
  				long unalignedIndex = reader.getPointerIndex();
  				reader.align(4);
  				long alignedIndex = reader.getPointerIndex();
  				remainingLength -= section.getTotalLength() + (alignedIndex - unalignedIndex);
  			}
  		}
  	}
  
  	/**
  	 * Returns the GUID for the current FFS file.
  	 *
  	 * @return the GUID for the current FFS file
  	 */
  	public UUID getGUID() {
  		return nameGuid;
  	}
  
  	/**
  	 * Returns the name of the current FFS file.
  	 *
  	 * @return the name of the current FFS file
  	 */
  	@Override
  	public String getName() {
  		// Use the UI section text (if present).
  		if (uiName != null) {
  			return uiName;
  		}
  
  		// Fall back to the GUID database if the UI section isn't present.
  		return UUIDUtils.getName(nameGuid);
  	}
  
  	/**
  	 * Returns the length of the current FFS file.
  	 *
  	 * @return the length of the current FFS file
  	 */
  	@Override
  	public long length() {
  		return size;
  	}
  
  	/**
  	 * Returns FileAttributes for the current FFS file.
  	 *
  	 * @return FileAttributes for the current FFS file
  	 */
  	public FileAttributes getFileAttributes() {
  		FileAttributes attributes = new FileAttributes();
  		attributes.add(FileAttributeType.NAME_ATTR, getName());
  		attributes.add(FileAttributeType.SIZE_ATTR, Long.valueOf(size));
  		attributes.add("GUID", nameGuid.toString());
  		attributes.add("Header Checksum", String.format("%#x", headerChecksum));
  		attributes.add("File Checksum", String.format("%#x", fileChecksum));
  		attributes.add("File Type", UEFIFFSConstants.FileType.toString(type));
  		attributes.add("Attributes", String.format("%#x", this.attributes));
  		attributes.add("State", String.format("%#x", state));
  		return attributes;
  	}
  }
  