bool IOGUIDPartitionScheme::isPartitionInvalid( gpt_ent * partition,
UInt32 partitionID )
{
//
// Ask whether the given partition appears to be invalid. A partition that
// is invalid will cause it to be skipped in the scan, but will not cause a
// failure of the GUID partition map recognition.
//
IOMedia * media = getProvider();
UInt64 mediaBlockSize = media->getPreferredBlockSize();
UInt64 partitionBase = 0;
UInt64 partitionSize = 0;
// Compute the relative byte position and size of the new partition.
partitionBase = OSSwapLittleToHostInt64(partition->ent_lba_start);
partitionSize = OSSwapLittleToHostInt64(partition->ent_lba_end);
partitionBase *= mediaBlockSize;
partitionSize *= mediaBlockSize;
// Determine whether the partition is a placeholder.
if ( partitionBase == partitionSize ) return true;
// Compute the relative byte position and size of the new partition.
partitionSize -= partitionBase - mediaBlockSize;
// Determine whether the new partition leaves the confines of the container.
if ( partitionBase + partitionSize > media->getSize() ) return true;
return false;
}
bool IOFDiskPartitionScheme::isPartitionInvalid( fdisk_part * partition,
UInt32 partitionID,
UInt32 fdiskBlock )
{
//
// Ask whether the given partition appears to be invalid. A partition that
// is invalid will cause it to be skipped in the scan, but will not cause a
// failure of the FDisk partition map recognition.
//
IOMedia * media = getProvider();
UInt64 mediaBlockSize = media->getPreferredBlockSize();
UInt64 partitionBase = 0;
UInt64 partitionSize = 0;
// Compute the relative byte position and size of the new partition.
partitionBase = OSSwapLittleToHostInt32(partition->relsect) + fdiskBlock;
partitionSize = OSSwapLittleToHostInt32(partition->numsect);
partitionBase *= mediaBlockSize;
partitionSize *= mediaBlockSize;
// Determine whether the partition shares space with the partition map.
if ( partitionBase == fdiskBlock * mediaBlockSize ) return true;
// Determine whether the partition starts at (or past) the end-of-media.
if ( partitionBase >= media->getSize() ) return true;
return false;
}
IOMedia * IOFDiskPartitionScheme::instantiateMediaObject(
fdisk_part * partition,
UInt32 partitionID,
UInt32 fdiskBlock )
{
//
// Instantiate a new media object to represent the given partition.
//
IOMedia * media = getProvider();
UInt64 mediaBlockSize = media->getPreferredBlockSize();
UInt64 partitionBase = 0;
char * partitionHint = 0;
UInt64 partitionSize = 0;
// Compute the relative byte position and size of the new partition.
partitionBase = OSSwapLittleToHostInt32(partition->relsect) + fdiskBlock;
partitionSize = OSSwapLittleToHostInt32(partition->numsect);
partitionBase *= mediaBlockSize;
partitionSize *= mediaBlockSize;
// Clip the size of the new partition if it extends past the end-of-media.
if ( partitionBase + partitionSize > media->getSize() )
{
partitionSize = media->getSize() - partitionBase;
}
// Look up a type for the new partition.
char hintIndex[5];
snprintf(hintIndex, sizeof(hintIndex), "0x%02X", partition->systid & 0xFF);
partitionHint = hintIndex;
OSDictionary * hintTable = OSDynamicCast(
/* type */ OSDictionary,
/* instance */ getProperty(kIOFDiskPartitionSchemeContentTable) );
if ( hintTable )
{
OSString * hintValue;
hintValue = OSDynamicCast(OSString, hintTable->getObject(hintIndex));
if ( hintValue ) partitionHint = (char *) hintValue->getCStringNoCopy();
}
// Create the new media object.
IOMedia * newMedia = instantiateDesiredMediaObject(
/* partition */ partition,
/* partitionID */ partitionID,
/* fdiskBlock */ fdiskBlock );
if ( newMedia )
{
if ( newMedia->init(
/* base */ partitionBase,
/* size */ partitionSize,
/* preferredBlockSize */ mediaBlockSize,
/* attributes */ media->getAttributes(),
/* isWhole */ false,
/* isWritable */ media->isWritable(),
/* contentHint */ partitionHint ) )
{
// Set a name for this partition.
char name[24];
snprintf(name, sizeof(name), "Untitled %d", (int) partitionID);
newMedia->setName(name);
// Set a location value (the partition number) for this partition.
char location[12];
snprintf(location, sizeof(location), "%d", (int) partitionID);
newMedia->setLocation(location);
// Set the "Partition ID" key for this partition.
newMedia->setProperty(kIOMediaPartitionIDKey, partitionID, 32);
}
else
{
newMedia->release();
newMedia = 0;
}
}
return newMedia;
}
OSSet * IOFDiskPartitionScheme::scan(SInt32 * score)
{
//
// Scan the provider media for an FDisk partition map. Returns the set
// of media objects representing each of the partitions (the retain for
// the set is passed to the caller), or null should no partition map be
// found. The default probe score can be adjusted up or down, based on
// the confidence of the scan.
//
IOBufferMemoryDescriptor * buffer = 0;
UInt32 bufferSize = 0;
UInt32 fdiskBlock = 0;
UInt32 fdiskBlockExtn = 0;
UInt32 fdiskBlockNext = 0;
UInt32 fdiskID = 0;
disk_blk0 * fdiskMap = 0;
IOMedia * media = getProvider();
UInt64 mediaBlockSize = media->getPreferredBlockSize();
bool mediaIsOpen = false;
OSSet * partitions = 0;
IOReturn status = kIOReturnError;
// Determine whether this media is formatted.
if ( media->isFormatted() == false ) goto scanErr;
// Determine whether this media has an appropriate block size.
if ( (mediaBlockSize % sizeof(disk_blk0)) ) goto scanErr;
// Allocate a buffer large enough to hold one map, rounded to a media block.
bufferSize = IORound(sizeof(disk_blk0), mediaBlockSize);
buffer = IOBufferMemoryDescriptor::withCapacity(
/* capacity */ bufferSize,
/* withDirection */ kIODirectionIn );
if ( buffer == 0 ) goto scanErr;
// Allocate a set to hold the set of media objects representing partitions.
partitions = OSSet::withCapacity(4);
if ( partitions == 0 ) goto scanErr;
// Open the media with read access.
mediaIsOpen = open(this, 0, kIOStorageAccessReader);
if ( mediaIsOpen == false ) goto scanErr;
// Scan the media for FDisk partition map(s).
do
{
// Read the next FDisk map into our buffer.
status = media->read(this, fdiskBlock * mediaBlockSize, buffer);
if ( status != kIOReturnSuccess ) goto scanErr;
fdiskMap = (disk_blk0 *) buffer->getBytesNoCopy();
// Determine whether the partition map signature is present.
if ( OSSwapLittleToHostInt16(fdiskMap->signature) != DISK_SIGNATURE )
{
goto scanErr;
}
// Scan for valid partition entries in the partition map.
fdiskBlockNext = 0;
for ( unsigned index = 0; index < DISK_NPART; index++ )
{
// Determine whether this is an extended (vs. data) partition.
if ( isPartitionExtended(fdiskMap->parts + index) ) // (extended)
{
// If peer extended partitions exist, we accept only the first.
if ( fdiskBlockNext == 0 ) // (no peer extended partition)
{
fdiskBlockNext = fdiskBlockExtn +
OSSwapLittleToHostInt32(
/* data */ fdiskMap->parts[index].relsect );
if ( fdiskBlockNext * mediaBlockSize >= media->getSize() )
{
fdiskBlockNext = 0; // (exceeds confines of media)
}
}
}
else if ( isPartitionUsed(fdiskMap->parts + index) ) // (data)
{
// Prepare this partition's ID.
fdiskID = ( fdiskBlock == 0 ) ? (index + 1) : (fdiskID + 1);
// Determine whether the partition is corrupt (fatal).
if ( isPartitionCorrupt(
/* partition */ fdiskMap->parts + index,
/* partitionID */ fdiskID,
/* fdiskBlock */ fdiskBlock ) )
{
goto scanErr;
}
// Determine whether the partition is invalid (skipped).
if ( isPartitionInvalid(
/* partition */ fdiskMap->parts + index,
/* partitionID */ fdiskID,
/* fdiskBlock */ fdiskBlock ) )
{
continue;
}
// Create a media object to represent this partition.
IOMedia * newMedia = instantiateMediaObject(
/* partition */ fdiskMap->parts + index,
/* partitionID */ fdiskID,
/* fdiskBlock */ fdiskBlock );
if ( newMedia )
{
partitions->setObject(newMedia);
newMedia->release();
}
}
}
// Prepare for first extended partition, if any.
if ( fdiskBlock == 0 )
{
fdiskID = DISK_NPART;
fdiskBlockExtn = fdiskBlockNext;
}
} while ( (fdiskBlock = fdiskBlockNext) );
// Release our resources.
close(this);
buffer->release();
return partitions;
scanErr:
// Release our resources.
if ( mediaIsOpen ) close(this);
if ( partitions ) partitions->release();
if ( buffer ) buffer->release();
return 0;
}
