/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the tools applications of the Qt Toolkit.
**
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
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****************************************************************************/

#ifndef ELFREADER_H
#define ELFREADER_H

#include <QtCore/QtEndian>
#include <QtCore/QString>
#include <QtCore/QVector>

QT_BEGIN_NAMESPACE

enum ElfProgramHeaderType
{
    Elf_PT_NULL    = 0,
    Elf_PT_LOAD    = 1,
    Elf_PT_DYNAMIC = 2,
    Elf_PT_INTERP  = 3,
    Elf_PT_NOTE    = 4,
    Elf_PT_SHLIB   = 5,
    Elf_PT_PHDR    = 6,
    Elf_PT_TLS     = 7,
    Elf_PT_NUM     = 8
};

enum ElfSectionHeaderType
{
    Elf_SHT_NULL          = 0,
    Elf_SHT_PROGBITS      = 1,
    Elf_SHT_SYMTAB        = 2,
    Elf_SHT_STRTAB        = 3,
    Elf_SHT_RELA          = 4,
    Elf_SHT_HASH          = 5,
    Elf_SHT_DYNAMIC       = 6,
    Elf_SHT_NOTE          = 7,
    Elf_SHT_NOBITS        = 8,
    Elf_SHT_REL           = 9,
    Elf_SHT_SHLIB         = 10,
    Elf_SHT_DYNSYM        = 11,
    Elf_SHT_INIT_ARRAY    = 14,
    Elf_SHT_FINI_ARRAY    = 15,
    Elf_SHT_PREINIT_ARRAY = 16,
    Elf_SHT_GROUP         = 17,
    Elf_SHT_SYMTAB_SHNDX  = 18
};

enum ElfEndian
{
    Elf_ELFDATANONE = 0,
    Elf_ELFDATA2LSB = 1,
    Elf_ELFDATA2MSB = 2,
    Elf_ELFDATANUM  = 3
};

enum ElfClass
{
    Elf_ELFCLASS32 = 1,
    Elf_ELFCLASS64 = 2
};

enum ElfType
{
    Elf_ET_NONE = 0,
    Elf_ET_REL  = 1,
    Elf_ET_EXEC = 2,
    Elf_ET_DYN  = 3,
    Elf_ET_CORE = 4
};

enum ElfMachine
{
    Elf_EM_386    =  3,
    Elf_EM_ARM    = 40,
    Elf_EM_X86_64 = 62
};

enum DebugSymbolsType
{
    UnknownSymbols   = 0,    // Unknown.
    NoSymbols        = 1,    // No usable symbols.
    LinkedSymbols    = 2,    // Link to symols available.
    BuildIdSymbols   = 4,    // BuildId available.
    PlainSymbols     = 8,    // Ordinary symbols available.
    FastSymbols      = 16    // Dwarf index available.
};

class ElfSectionHeader
{
public:
    QByteArray name;
    quint32 index;
    quint32 type;
    quint32 flags;
    quint64 offset;
    quint64 size;
    quint64 addr;
};

class ElfProgramHeader
{
public:
    quint32 name;
    quint32 type;
    quint64 offset;
    quint64 filesz;
    quint64 memsz;
};

class ElfData
{
public:
    ElfData() : symbolsType(UnknownSymbols) {}
    int indexOf(const QByteArray &name) const;

public:
    ElfEndian  endian;
    ElfType    elftype;
    ElfMachine elfmachine;
    ElfClass   elfclass;
    quint64    entryPoint;
    QByteArray debugLink;
    QByteArray buildId;
    DebugSymbolsType symbolsType;
    QVector<ElfSectionHeader> sectionHeaders;
    QVector<ElfProgramHeader> programHeaders;
};

class ElfReader
{
public:
    explicit ElfReader(const QString &binary);
    enum Result { Ok, NotElf, Corrupt };

    ElfData readHeaders();
    QByteArray readSection(const QByteArray &sectionName);
    QString errorString() const { return m_errorString; }
    QByteArray readCoreName(bool *isCore);
    QList<QByteArray> dependencies();

private:
    friend class ElfMapper;
    Result readIt();

    QString m_binary;
    QString m_errorString;
    ElfData m_elfData;
};

QT_END_NAMESPACE

#endif // ELFREADER_H