darling-iostoragefamily/IOFDiskPartitionScheme.cpp
2016-11-28 14:08:04 +01:00

581 lines
18 KiB
C++

/*
* Copyright (c) 1998-2014 Apple Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
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* @APPLE_LICENSE_HEADER_END@
*/
#include <IOKit/assert.h>
#include <IOKit/IOBufferMemoryDescriptor.h>
#include <IOKit/IOLib.h>
#include <IOKit/storage/IOFDiskPartitionScheme.h>
#include <libkern/OSByteOrder.h>
#define super IOPartitionScheme
OSDefineMetaClassAndStructors(IOFDiskPartitionScheme, IOPartitionScheme);
//
// Notes
//
// o the on-disk structure's fields are little-endian formatted
// o the relsect and numsect block values assume the drive's natural block size
// o the relsect block value is:
// o for data partitions:
// o relative to the FDisk map that defines the partition
// o for extended partitions defined in the root-level FDisk map:
// o relative to the FDisk map that defines the partition (start of disk)
// o for extended partitions defined in a second-level or deeper FDisk map:
// o relative to the second-level FDisk map, regardless of depth
// o the valid extended partition types are: 0x05, 0x0F, 0x85
// o there should be no more than one extended partition defined per FDisk map
//
#define kIOFDiskPartitionSchemeContentTable "Content Table"
bool IOFDiskPartitionScheme::init(OSDictionary * properties)
{
//
// Initialize this object's minimal state.
//
// State our assumptions.
assert(sizeof(fdisk_part) == 16); // (compiler/platform check)
assert(sizeof(disk_blk0) == 512); // (compiler/platform check)
// Ask our superclass' opinion.
if ( super::init(properties) == false ) return false;
// Initialize our state.
_partitions = 0;
return true;
}
void IOFDiskPartitionScheme::free()
{
//
// Free all of this object's outstanding resources.
//
if ( _partitions ) _partitions->release();
super::free();
}
IOService * IOFDiskPartitionScheme::probe(IOService * provider, SInt32 * score)
{
//
// Determine whether the provider media contains an FDisk partition map.
//
// State our assumptions.
assert(OSDynamicCast(IOMedia, provider));
// Ask our superclass' opinion.
if ( super::probe(provider, score) == 0 ) return 0;
// Scan the provider media for an FDisk partition map.
_partitions = scan(score);
// There might be an FDisk partition scheme on disk with boot code, but with
// no partitions defined. We don't consider this a match and return failure
// from probe.
if ( _partitions && _partitions->getCount() == 0 )
{
_partitions->release();
_partitions = 0;
}
return ( _partitions ) ? this : 0;
}
bool IOFDiskPartitionScheme::start(IOService * provider)
{
//
// Publish the new media objects which represent our partitions.
//
IOMedia * partition;
OSIterator * partitionIterator;
// State our assumptions.
assert(_partitions);
// Ask our superclass' opinion.
if ( super::start(provider) == false ) return false;
// Attach and register the new media objects representing our partitions.
partitionIterator = OSCollectionIterator::withCollection(_partitions);
if ( partitionIterator == 0 ) return false;
while ( (partition = (IOMedia *) partitionIterator->getNextObject()) )
{
if ( partition->attach(this) )
{
attachMediaObjectToDeviceTree(partition);
partition->registerService();
}
}
partitionIterator->release();
// set partition scheme to be valid
_partitionSchemeState |= kIOPartitionScheme_partition_valid;
return true;
}
void IOFDiskPartitionScheme::stop(IOService * provider)
{
//
// Clean up after the media objects we published before terminating.
//
IOMedia * partition;
OSIterator * partitionIterator;
// State our assumptions.
assert(_partitions);
// Detach the media objects we previously attached to the device tree.
partitionIterator = OSCollectionIterator::withCollection(_partitions);
if ( partitionIterator )
{
while ( (partition = (IOMedia *) partitionIterator->getNextObject()) )
{
detachMediaObjectFromDeviceTree(partition);
}
partitionIterator->release();
}
super::stop(provider);
}
IOReturn IOFDiskPartitionScheme::requestProbe(IOOptionBits options)
{
//
// Request that the provider media be re-scanned for partitions.
//
OSSet * partitions = 0;
OSSet * partitionsNew;
SInt32 score = 0;
// Scan the provider media for partitions.
if ( ( _partitionSchemeState & kIOPartitionScheme_partition_valid ) == 0 )
{
return kIOReturnError;
}
partitionsNew = scan( &score );
if ( partitionsNew )
{
if ( lockForArbitration( false ) )
{
partitions = juxtaposeMediaObjects( _partitions, partitionsNew );
if ( partitions )
{
_partitions->release( );
_partitions = partitions;
}
unlockForArbitration( );
}
partitionsNew->release( );
}
return partitions ? kIOReturnSuccess : kIOReturnError;
}
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;
IOByteCount 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;
}
bool IOFDiskPartitionScheme::isPartitionExtended(fdisk_part * partition)
{
//
// Ask whether the given partition is extended.
//
return ( partition->systid == 0x05 ||
partition->systid == 0x0F ||
partition->systid == 0x85 );
}
bool IOFDiskPartitionScheme::isPartitionUsed(fdisk_part * partition)
{
//
// Ask whether the given partition is used.
//
return ( partition->systid != 0 && partition->numsect != 0 );
}
bool IOFDiskPartitionScheme::isPartitionCorrupt( fdisk_part * partition,
UInt32 partitionID,
UInt32 fdiskBlock )
{
//
// Ask whether the given partition appears to be corrupt. A partition that
// is corrupt will cause the failure of the FDisk partition map recognition
// altogether.
//
// Determine whether the boot indicator is valid.
if ( (partition->bootid & 0x7F) ) 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 "Base" key for this partition.
newMedia->setProperty(kIOMediaBaseKey, partitionBase, 64);
// Set the "Partition ID" key for this partition.
newMedia->setProperty(kIOMediaPartitionIDKey, partitionID, 32);
}
else
{
newMedia->release();
newMedia = 0;
}
}
return newMedia;
}
IOMedia * IOFDiskPartitionScheme::instantiateDesiredMediaObject(
fdisk_part * partition,
UInt32 partitionID,
UInt32 fdiskBlock )
{
//
// Allocate a new media object (called from instantiateMediaObject).
//
return new IOMedia;
}
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 0);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 1);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 2);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 3);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 4);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 5);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 6);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 7);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 8);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 9);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 10);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 11);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 12);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 13);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 14);
OSMetaClassDefineReservedUnused(IOFDiskPartitionScheme, 15);