MaxOS::processes::ELF64 Class Reference

Handles the loading and parsing of 64-bit ELF files. More...

#include <elf.h>

Public Member Functions
	ELF64 (uintptr_t elf_header_address)
	Constructor for the ELF64 class.
	~ELF64 ()
	Destructor for the ELF64 class.
void	load ()
	Loads the elf program into memory if a valid elf file.
bool	is_valid () const
	Checks if the elf file is valid for MaxOS runtime.
elf_64_header_t *	header () const
	Gets the header of the elf file.
elf_64_program_header_t *	get_program_header (size_t index) const
	Gets a program header from the elf file.
elf_64_section_header_t *	get_section_header (size_t index) const
	Gets a section header from the elf file.

Static Public Member Functions
static uint64_t	to_vmm_flags (uint32_t type)
	Converts elf flags to vmm flags.

Detailed Description

Handles the loading and parsing of 64-bit ELF files.

Definition at line 217 of file elf.h.

Constructor & Destructor Documentation

ELF64()

ELF64::ELF64 ( uintptr_t  elf_header_address )

explicit

Constructor for the ELF64 class.

Parameters

elf_header_address

The address of the elf header, this must be mapped to memory before uses

Definition at line 23 of file elf.cpp.

: m_elf_header_address(elf_header_address)
{
}

Member Function Documentation

get_program_header()

elf_64_program_header_t * ELF64::get_program_header

(

size_t

index

)

const

Gets a program header from the elf file.

Parameters

index

The index of the program header

Returns

The program header at that index or nullptr if out of bounds

Definition at line 63 of file elf.cpp.

                                                                     {
 
    // Check bounds
    if (index >= header()->program_header_count)
        return nullptr;
 
    // Find the program headers and return the item
    auto* program_headers = (elf_64_program_header_t*) (m_elf_header_address + header()->program_header_offset);
    return &program_headers[index];
 
}

References header(), and MaxOS::processes::ELFHeader64::program_header_offset.

get_section_header()

elf_64_section_header_t * ELF64::get_section_header

(

size_t

index

)

const

Gets a section header from the elf file.

Parameters

index

The index of the section header

Returns

The section header at that index or nullptr if out of bounds

Definition at line 81 of file elf.cpp.

                                                                     {
 
    // Check bound
    if (index >= header()->section_header_count)
        return nullptr;
 
    // Find the section headers and return the item
    auto* section_headers = (elf_64_section_header_t*) (m_elf_header_address + header()->section_header_offset);
    return &section_headers[index];
 
}

References header(), and MaxOS::processes::ELFHeader64::section_header_offset.

header()

elf_64_header_t * ELF64::header

(

)

const

Gets the header of the elf file.

Returns

The header of the elf file

Definition at line 52 of file elf.cpp.

                                     {
 
    return (elf_64_header_t*) m_elf_header_address;
}

Referenced by get_program_header(), get_section_header(), and is_valid().

is_valid()

bool ELF64::is_valid

(

)

const

Checks if the elf file is valid for MaxOS runtime.

Returns

True if the elf file is valid, false otherwise

Todo:

Add support for maxOS ABI

Definition at line 100 of file elf.cpp.

                           {
 
    // Validate the magic number
    for (size_t i = 0; i < 4; i++)
        if (header()->identification[i] != ELF_MAGIC[i])
            return false;
 
    // Check if the elf is 64 bit
    if (header()->identification[(int) ELFIdentification::Class] != (int) ELFClass::Bits64)
        return false;
 
    // Check if the elf is little endian
    if (header()->identification[(int) ELFIdentification::Data] != (int) ELFData::LittleEndian)
        return false;
 
    // Check if the elf is version 1
    if (header()->identification[(int) ELFIdentification::Version] != (int) ELFVersion::Current)
        return false;
 
    // Check if the elf is for the MaxOS platform
    //  if(header() -> identification[OSABI] != MaxOSABI)
    //      return false;
 
    // Check if the elf is executable
    if (header()->type != (int) ELFType::Executable)
        return false;
 
    // Check if the elf is for the x86_64 platform
    if (header()->machine != (int) ELFMachine::x86_64)
        return false;
 
    // LGTM
    return true;
 
}

References MaxOS::processes::ELF_MAGIC, and header().

Referenced by load(), and MaxOS::processes::GlobalScheduler::load_multiboot_elfs().

load()

void ELF64::load

(

)

Loads the elf program into memory if a valid elf file.

Todo:

Error handling

Definition at line 38 of file elf.cpp.

                 {
 
    if (!is_valid())
        return;
 
    load_program_headers();
 
}

References is_valid().

to_vmm_flags()

uint64_t ELF64::to_vmm_flags ( uint32_t  type )

static

Converts elf flags to vmm flags.

Parameters

type	The elf flags of the program header

Returns

The vmm flags

Definition at line 173 of file elf.cpp.

                                          {
 
    // Conversion
    // ELF   |   VMM
    // 0x0   |   Executable
    // 0x1   |   Write
    // 0x2   |   Read
 
    uint64_t flags = PRESENT | USER | NO_EXECUTE;
 
    // Enable write
    if (type & ELFWrite)
        flags |= WRITE;
 
    // Disable no execute
    if (type & ELFExecute)
        flags &= ~NO_EXECUTE;
 
    return flags;
}

References MaxOS::memory::NO_EXECUTE, MaxOS::memory::PRESENT, MaxOS::memory::USER, and MaxOS::memory::WRITE.

---

The documentation for this class was generated from the following files:

• /home/runner/work/MaxOS/MaxOS/kernel/include/processes/elf.h
• /home/runner/work/MaxOS/MaxOS/kernel/src/processes/elf.cpp