status_t
Header::Write(int fd)
{
// Try to write the protective MBR
PartitionMap partitionMap;
PrimaryPartition *partition = NULL;
uint32 index = 0;
while ((partition = partitionMap.PrimaryPartitionAt(index)) != NULL) {
if (index == 0) {
uint64 deviceSize = fHeader.AlternateBlock() * fBlockSize;
partition->SetTo(fBlockSize, deviceSize, 0xEE, false, fBlockSize);
} else
partition->Unset();
++index;
}
PartitionMapWriter writer(fd, fBlockSize);
writer.WriteMBR(&partitionMap, true);
// We also write the bootcode, so we can boot GPT disks from BIOS
status_t status = _Write(fd, fHeader.EntriesBlock() * fBlockSize, fEntries,
_EntryArraySize());
if (status != B_OK)
return status;
// First write the header, so that we have at least one completely correct
// data set
status = _WriteHeader(fd);
// Write backup entries
status_t backupStatus = _Write(fd,
fBackupHeader.EntriesBlock() * fBlockSize, fEntries, _EntryArraySize());
return status == B_OK ? backupStatus : status;
}
void
Header::_UpdateCRC(efi_table_header& header)
{
header.SetEntriesCRC(crc32(fEntries, _EntryArraySize()));
header.SetHeaderCRC(0);
header.SetHeaderCRC(crc32((uint8*)&header, sizeof(efi_table_header)));
}
void
Header::_SetBackupHeaderFromPrimary(uint64 lastBlock)
{
fBackupHeader = fHeader;
fBackupHeader.SetAbsoluteBlock(lastBlock);
fBackupHeader.SetEntriesBlock(
lastBlock - _EntryArraySize() / fBlockSize);
fBackupHeader.SetAlternateBlock(1);
}
status_t
Header::Write(int fd)
{
status_t status = _Write(fd, fHeader.EntriesBlock() * fBlockSize, fEntries,
_EntryArraySize());
if (status != B_OK)
return status;
// First write the header, so that we have at least one completely correct
// data set
status = _WriteHeader(fd);
// Write backup entries
status_t backupStatus = _Write(fd,
fBackupHeader.EntriesBlock() * fBlockSize, fEntries, _EntryArraySize());
return status == B_OK ? backupStatus : status;
}
Header::Header(uint64 lastBlock, uint32 blockSize)
:
fBlockSize(blockSize),
fStatus(B_NO_INIT),
fEntries(NULL)
{
TRACE(("EFI::Header: Initialize GPT, block size %" B_PRIu32 "\n",
blockSize));
// Initialize to an empty header
memcpy(fHeader.header, EFI_PARTITION_HEADER, sizeof(fHeader.header));
fHeader.SetRevision(EFI_TABLE_REVISION);
fHeader.SetHeaderSize(sizeof(fHeader));
fHeader.SetHeaderCRC(0);
fHeader.SetAbsoluteBlock(EFI_HEADER_LOCATION);
fHeader.SetAlternateBlock(lastBlock);
uuid_t uuid;
uuid_generate_random(uuid);
memcpy((uint8*)&fHeader.disk_guid, uuid, sizeof(guid_t));
fHeader.SetEntriesBlock(EFI_PARTITION_ENTRIES_BLOCK);
fHeader.SetEntryCount(EFI_PARTITION_ENTRY_COUNT);
fHeader.SetEntrySize(EFI_PARTITION_ENTRY_SIZE);
fHeader.SetEntriesCRC(0);
size_t arraySize = _EntryArraySize();
fEntries = new (std::nothrow) uint8[arraySize];
if (fEntries == NULL) {
fStatus = B_NO_MEMORY;
return;
}
memset(fEntries, 0, arraySize);
// TODO: initialize the entry guids
uint32 entryBlocks = (arraySize + fBlockSize - 1) / fBlockSize;
fHeader.SetFirstUsableBlock(EFI_PARTITION_ENTRIES_BLOCK + entryBlocks);
fHeader.SetLastUsableBlock(lastBlock - 1 - entryBlocks);
_SetBackupHeaderFromPrimary(lastBlock);
#ifdef TRACE_EFI_GPT
_Dump(fHeader);
_DumpPartitions();
#endif
fStatus = B_OK;
}
Header::Header(int fd, uint64 lastBlock, uint32 blockSize)
:
fBlockSize(blockSize),
fStatus(B_NO_INIT),
fEntries(NULL)
{
// TODO: check the correctness of the protective MBR and warn if invalid
// Read and check the partition table header
fStatus = _Read(fd, (uint64)EFI_HEADER_LOCATION * blockSize,
&fHeader, sizeof(efi_table_header));
if (fStatus == B_OK) {
if (!_IsHeaderValid(fHeader, EFI_HEADER_LOCATION))
fStatus = B_BAD_DATA;
}
if (fStatus == B_OK && lastBlock != fHeader.AlternateBlock()) {
dprintf("gpt: alternate header not in last block (%" B_PRIu64 " vs. %"
B_PRIu64 ")\n", fHeader.AlternateBlock(), lastBlock);
lastBlock = fHeader.AlternateBlock();
}
// Read backup header, too
status_t status = _Read(fd, lastBlock * blockSize, &fBackupHeader,
sizeof(efi_table_header));
if (status == B_OK) {
if (!_IsHeaderValid(fBackupHeader, lastBlock))
status = B_BAD_DATA;
}
// If both headers are invalid, bail out -- this is probably not a GPT disk
if (status != B_OK && fStatus != B_OK)
return;
if (fStatus != B_OK) {
// Recreate primary header from the backup
fHeader = fBackupHeader;
fHeader.SetAbsoluteBlock(EFI_HEADER_LOCATION);
fHeader.SetEntriesBlock(EFI_PARTITION_ENTRIES_BLOCK);
fHeader.SetAlternateBlock(lastBlock);
} else if (status != B_OK) {
// Recreate backup header from primary
_SetBackupHeaderFromPrimary(lastBlock);
}
// allocate, read, and check partition entry array
fEntries = new (std::nothrow) uint8[_EntryArraySize()];
if (fEntries == NULL) {
// TODO: if there cannot be allocated enough (ie. the boot loader's
// heap is limited), try a smaller size before failing
fStatus = B_NO_MEMORY;
return;
}
fStatus = _Read(fd, fHeader.EntriesBlock() * blockSize,
fEntries, _EntryArraySize());
if (fStatus != B_OK || !_ValidateEntriesCRC()) {
// Read backup entries instead
fStatus = _Read(fd, fBackupHeader.EntriesBlock() * blockSize,
fEntries, _EntryArraySize());
if (fStatus != B_OK)
return;
if (!_ValidateEntriesCRC()) {
fStatus = B_BAD_DATA;
return;
}
}
// TODO: check overlapping or out of range partitions
#ifdef TRACE_EFI_GPT
_Dump(fHeader);
_Dump(fBackupHeader);
_DumpPartitions();
#endif
fStatus = B_OK;
}
bool
Header::_ValidateEntriesCRC() const
{
return fHeader.EntriesCRC() == crc32(fEntries, _EntryArraySize());
}
