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Kernel: Introduce a new partitioning subsystem

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The partitioning code was very outdated, and required a full refactor.
The new subsystem removes duplicated code and uses more AK containers.

The most important change is that all implementations of the
PartitionTable class conform to one interface, which made it possible
to remove unnecessary code in the EBRPartitionTable class.

Finding partitions is now done in the StorageManagement singleton,
instead of doing so in init.cpp.

Also, now we don't try to find partitions on demand - the kernel will
try to detect if a StorageDevice is partitioned, and if so, will check
what is the partition table, which could be MBR, GUID or EBR.
Then, it will create DiskPartitionMetadata object for each partition
that is available in the partition table. This object will be used
by the partition enumeration code to create a DiskPartition with the
correct minor number.
This commit is contained in:
Liav A 2020-12-26 16:53:30 +02:00 • committed by Andreas Kling
parent bc18712adf
commit 72b1998f0d
20 changed files with 639 additions and 561 deletions
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87
Kernel/Storage/Partition/MBRPartitionTable.h
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -26,57 +26,64 @@
#pragma once
#include <AK/ByteBuffer.h>
#include <AK/RefPtr.h>
#include <AK/Result.h>
#include <AK/Vector.h>
#include <Kernel/Storage/Partition/DiskPartition.h>
#include <Kernel/Storage/Partition/PartitionTable.h>
namespace Kernel {
#define MBR_SIGNATURE 0xaa55
#define MBR_PROTECTIVE 0xEE
#define EBR_CHS_CONTAINER 0x05
#define EBR_LBA_CONTAINER 0x0F
struct [[gnu::packed]] MBRPartitionEntry
{
u8 status;
u8 chs1[3];
u8 type;
u8 chs2[3];
u32 offset;
u32 length;
};
struct [[gnu::packed]] MBRPartitionHeader
{
u8 code1[218];
u16 ts_zero;
u8 ts_drive, ts_seconds, ts_minutes, ts_hours;
u8 code2[216];
u32 disk_signature;
u16 disk_signature_zero;
MBRPartitionEntry entry[4];
u16 mbr_signature;
};
class MBRPartitionTable {
AK_MAKE_ETERNAL
class MBRPartitionTable : public PartitionTable {
public:
struct [[gnu::packed]] Entry
{
u8 status;
u8 chs1[3];
u8 type;
u8 chs2[3];
u32 offset;
u32 length;
};
struct [[gnu::packed]] Header
{
u8 code1[218];
u16 ts_zero;
u8 ts_drive;
u8 ts_seconds;
u8 ts_minutes;
u8 ts_hours;
u8 code2[216];
u32 disk_signature;
u16 disk_signature_zero;
Entry entry[4];
u16 mbr_signature;
};
public:
explicit MBRPartitionTable(NonnullRefPtr<BlockDevice>);
~MBRPartitionTable();
bool initialize();
static Result<NonnullOwnPtr<MBRPartitionTable>, PartitionTable::Error> try_to_initialize(const StorageDevice&);
static OwnPtr<MBRPartitionTable> try_to_initialize(const StorageDevice&, u32 start_lba);
explicit MBRPartitionTable(const StorageDevice&);
MBRPartitionTable(const StorageDevice&, u32 start_lba);
bool is_protective_mbr() const;
bool contains_ebr() const;
RefPtr<DiskPartition> partition(unsigned index);
virtual Type type() const override { return Type::MBR; };
virtual bool is_valid() const override { return m_valid; };
protected:
const Header& header() const;
bool is_header_valid() const { return m_header_valid; };
private:
NonnullRefPtr<BlockDevice> m_device;
const MBRPartitionHeader& header() const;
u8 m_cached_header[512];
bool read_boot_record();
bool initialize();
bool m_valid { false };
bool m_header_valid { false };
const u32 m_start_lba;
ByteBuffer m_cached_header;
size_t m_partitions_count { 0 };
};
}