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LibELF: Add 32 bit support

This commit is contained in:
Bananymous 2023-04-22 18:57:24 +03:00
parent 4f8f3ddc29
commit 163d2e4ba8
3 changed files with 332 additions and 71 deletions
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294
LibELF/LibELF/ELF.cpp
View File

@ -40,12 +40,106 @@ namespace LibELF
return elf;
}
const char* ELF::lookup_section_name(uint32_t offset) const
BAN::ErrorOr<void> ELF::load()
{
return lookup_string(file_header64().e_shstrndx, offset);
if (m_data.size() < EI_NIDENT)
{
dprintln("Too small ELF file");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_MAG0] != ELFMAG0 ||
m_data[EI_MAG1] != ELFMAG1 ||
m_data[EI_MAG2] != ELFMAG2 ||
m_data[EI_MAG3] != ELFMAG3)
{
dprintln("Invalid ELF header");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_DATA] != ELFDATA2LSB)
{
dprintln("Only little-endian is supported");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_VERSION] != EV_CURRENT)
{
dprintln("Invalid ELF version");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_CLASS] == ELFCLASS64)
{
if (m_data.size() <= sizeof(Elf64FileHeader))
{
dprintln("Too small ELF file");
return BAN::Error::from_errno(EINVAL);
}
auto& header = file_header64();
if (!parse_elf64_file_header(header))
return BAN::Error::from_errno(EINVAL);
for (size_t i = 0; i < header.e_phnum; i++)
{
auto& program_header = program_header64(i);
if (!parse_elf64_program_header(program_header))
return BAN::Error::from_errno(EINVAL);
}
for (size_t i = 1; i < header.e_shnum; i++)
{
auto& section_header = section_header64(i);
if (!parse_elf64_section_header(section_header))
return BAN::Error::from_errno(EINVAL);
}
}
else if (m_data[EI_CLASS] == ELFCLASS32)
{
if (m_data.size() <= sizeof(Elf32FileHeader))
{
dprintln("Too small ELF file");
return BAN::Error::from_errno(EINVAL);
}
auto& header = file_header32();
if (!parse_elf32_file_header(header))
return BAN::Error::from_errno(EINVAL);
for (size_t i = 0; i < header.e_phnum; i++)
{
auto& program_header = program_header32(i);
if (!parse_elf32_program_header(program_header))
return BAN::Error::from_errno(EINVAL);
}
for (size_t i = 1; i < header.e_shnum; i++)
{
auto& section_header = section_header32(i);
if (!parse_elf32_section_header(section_header))
return BAN::Error::from_errno(EINVAL);
}
}
return {};
}
const char* ELF::lookup_string(size_t table_index, uint32_t offset) const
bool ELF::is_x86_32() const { return m_data[EI_CLASS] == ELFCLASS32; }
bool ELF::is_x86_64() const { return m_data[EI_CLASS] == ELFCLASS64; }
/*
64 bit ELF
*/
const char* ELF::lookup_section_name64(uint32_t offset) const
{
return lookup_string64(file_header64().e_shstrndx, offset);
}
const char* ELF::lookup_string64(size_t table_index, uint32_t offset) const
{
if (table_index == SHN_UNDEF)
return nullptr;
@ -90,7 +184,7 @@ namespace LibELF
bool ELF::parse_elf64_section_header(const Elf64SectionHeader& header)
{
#if ELF_PRINT_HEADERS
if (auto* name = lookup_section_name(header.sh_name))
if (auto* name = lookup_section_name64(header.sh_name))
dprintln("{}", name);
switch (header.sh_type)
@ -105,7 +199,7 @@ namespace LibELF
for (size_t i = 1; i < header.sh_size / header.sh_entsize; i++)
{
auto& symbol = ((const Elf64Symbol*)(m_data.data() + header.sh_offset))[i];
if (auto* name = lookup_string(header.sh_link, symbol.st_name))
if (auto* name = lookup_string64(header.sh_link, symbol.st_name))
dprintln(" {}", name);
}
break;
@ -135,76 +229,15 @@ namespace LibELF
return true;
}
BAN::ErrorOr<void> ELF::load()
{
if (m_data.size() < EI_NIDENT)
{
dprintln("Too small ELF file");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_MAG0] != ELFMAG0 ||
m_data[EI_MAG1] != ELFMAG1 ||
m_data[EI_MAG2] != ELFMAG2 ||
m_data[EI_MAG3] != ELFMAG3)
{
dprintln("Invalid ELF header");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_DATA] != ELFDATA2LSB)
{
dprintln("Only little-endian is supported");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_VERSION] != EV_CURRENT)
{
dprintln("Invalid ELF version");
return BAN::Error::from_errno(EINVAL);
}
if (m_data[EI_CLASS] != ELFCLASS64)
{
dprintln("Only 64 bit is supported");
return BAN::Error::from_errno(EINVAL);
}
if (m_data.size() <= sizeof(Elf64FileHeader))
{
dprintln("Too small ELF file");
return BAN::Error::from_errno(EINVAL);
}
auto& header = file_header64();
if (!parse_elf64_file_header(header))
return BAN::Error::from_errno(EINVAL);
for (size_t i = 0; i < header.e_phnum; i++)
{
auto& program_header = program_header64(i);
if (!parse_elf64_program_header(program_header))
return BAN::Error::from_errno(EINVAL);
}
for (size_t i = 1; i < header.e_shnum; i++)
{
auto& section_header = section_header64(i);
if (!parse_elf64_section_header(section_header))
return BAN::Error::from_errno(EINVAL);
}
return {};
}
const Elf64FileHeader& ELF::file_header64() const
{
ASSERT(is_x86_64());
return *(const Elf64FileHeader*)m_data.data();
}
const Elf64ProgramHeader& ELF::program_header64(size_t index) const
{
ASSERT(is_x86_64());
const auto& file_header = file_header64();
ASSERT(index < file_header.e_phnum);
return *(const Elf64ProgramHeader*)(m_data.data() + file_header.e_phoff + file_header.e_phentsize * index);
@ -212,10 +245,135 @@ namespace LibELF
const Elf64SectionHeader& ELF::section_header64(size_t index) const
{
ASSERT(is_x86_64());
const auto& file_header = file_header64();
ASSERT(index < file_header.e_shnum);
return *(const Elf64SectionHeader*)(m_data.data() + file_header.e_shoff + file_header.e_shentsize * index);
}
/*
32 bit ELF
*/
const char* ELF::lookup_section_name32(uint32_t offset) const
{
return lookup_string32(file_header32().e_shstrndx, offset);
}
const char* ELF::lookup_string32(size_t table_index, uint32_t offset) const
{
if (table_index == SHN_UNDEF)
return nullptr;
auto& section_header = section_header32(table_index);
return (const char*)m_data.data() + section_header.sh_offset + offset;
}
bool ELF::parse_elf32_file_header(const Elf32FileHeader& header)
{
if (header.e_type != ET_EXEC)
{
dprintln("Only executable files are supported");
return false;
}
if (header.e_version != EV_CURRENT)
{
dprintln("Invalid ELF version");
return false;
}
return true;
}
bool ELF::parse_elf32_program_header(const Elf32ProgramHeader& header)
{
#if ELF_PRINT_HEADERS
dprintln("program header");
dprintln(" type {H}", header.p_type);
dprintln(" flags {H}", header.p_flags);
dprintln(" offset {H}", header.p_offset);
dprintln(" vaddr {H}", header.p_vaddr);
dprintln(" paddr {H}", header.p_paddr);
dprintln(" filesz {}", header.p_filesz);
dprintln(" memsz {}", header.p_memsz);
dprintln(" align {}", header.p_align);
#endif
(void)header;
return true;
}
bool ELF::parse_elf32_section_header(const Elf32SectionHeader& header)
{
#if ELF_PRINT_HEADERS
if (auto* name = lookup_section_name32(header.sh_name))
dprintln("{}", name);
switch (header.sh_type)
{
case SHT_NULL:
dprintln(" SHT_NULL");
break;
case SHT_PROGBITS:
dprintln(" SHT_PROGBITS");
break;
case SHT_SYMTAB:
for (size_t i = 1; i < header.sh_size / header.sh_entsize; i++)
{
auto& symbol = ((const Elf32Symbol*)(m_data.data() + header.sh_offset))[i];
if (auto* name = lookup_string32(header.sh_link, symbol.st_name))
dprintln(" {}", name);
}
break;
case SHT_STRTAB:
dprintln(" SHT_STRTAB");
break;
case SHT_RELA:
dprintln(" SHT_RELA");
break;
case SHT_NOBITS:
dprintln(" SHT_NOBITS");
break;
case SHT_REL:
dprintln(" SHT_REL");
break;
case SHT_SHLIB:
dprintln(" SHT_SHLIB");
break;
case SHT_DYNSYM:
dprintln(" SHT_DYNSYM");
break;
default:
ASSERT(false);
}
#endif
(void)header;
return true;
}
const Elf32FileHeader& ELF::file_header32() const
{
ASSERT(is_x86_32());
return *(const Elf32FileHeader*)m_data.data();
}
const Elf32ProgramHeader& ELF::program_header32(size_t index) const
{
ASSERT(is_x86_32());
const auto& file_header = file_header32();
ASSERT(index < file_header.e_phnum);
return *(const Elf32ProgramHeader*)(m_data.data() + file_header.e_phoff + file_header.e_phentsize * index);
}
const Elf32SectionHeader& ELF::section_header32(size_t index) const
{
ASSERT(is_x86_32());
const auto& file_header = file_header32();
ASSERT(index < file_header.e_shnum);
return *(const Elf32SectionHeader*)(m_data.data() + file_header.e_shoff + file_header.e_shentsize * index);
}
}

35
LibELF/include/LibELF/ELF.h
View File

@ -2,6 +2,7 @@
#include <BAN/StringView.h>
#include <BAN/Vector.h>
#include <kernel/Arch.h>
#include "Types.h"
namespace LibELF
@ -11,16 +12,40 @@ namespace LibELF
{
public:
static BAN::ErrorOr<ELF*> load_from_file(BAN::StringView);
const Elf64FileHeader& file_header64() const;
const Elf64ProgramHeader& program_header64(size_t) const;
const Elf64SectionHeader& section_header64(size_t) const;
const char* lookup_section_name64(uint32_t) const;
const char* lookup_string64(size_t, uint32_t) const;
#if ARCH(x86_64)
const Elf64FileHeader& file_header_native() const { return file_header64(); }
const Elf64ProgramHeader& program_header_native(size_t index) const { return program_header64(index); }
const Elf64SectionHeader& section_header_native(size_t index) const { return section_header64(index); }
const char* lookup_section_name_native(uint32_t offset) const { return lookup_section_name64(offset); }
const char* lookup_string_native(size_t table_index, uint32_t offset) const { return lookup_string64(table_index, offset); }
bool is_native() const { return is_x86_64(); }
#endif
const char* lookup_section_name(uint32_t) const;
const char* lookup_string(size_t, uint32_t) const;
const Elf32FileHeader& file_header32() const;
const Elf32ProgramHeader& program_header32(size_t) const;
const Elf32SectionHeader& section_header32(size_t) const;
const char* lookup_section_name32(uint32_t) const;
const char* lookup_string32(size_t, uint32_t) const;
#if ARCH(i386)
const Elf32FileHeader& file_header_native() const { return file_header32(); }
const Elf32ProgramHeader& program_header_native(size_t index) const { return program_header32(index); }
const Elf32SectionHeader& section_header_native(size_t index) const { return section_header32(index); }
const char* lookup_section_name_native(uint32_t offset) const { return lookup_section_name32(offset); }
const char* lookup_string_native(size_t table_index, uint32_t offset) const { return lookup_string32(table_index, offset); }
bool is_native() const { return is_x86_32(); }
#endif
const uint8_t* data() const { return m_data.data(); }
bool is_x86_32() const;
bool is_x86_64() const;
private:
ELF(BAN::Vector<uint8_t>&& data)
: m_data(BAN::move(data))
@ -31,6 +56,10 @@ namespace LibELF
bool parse_elf64_program_header(const Elf64ProgramHeader&);
bool parse_elf64_section_header(const Elf64SectionHeader&);
bool parse_elf32_file_header(const Elf32FileHeader&);
bool parse_elf32_program_header(const Elf32ProgramHeader&);
bool parse_elf32_section_header(const Elf32SectionHeader&);
private:
const BAN::Vector<uint8_t> m_data;
};

74
LibELF/include/LibELF/Types.h
View File

@ -5,6 +5,80 @@
namespace LibELF
{
using Elf32Addr = uint32_t;
using Elf32Off = uint32_t;
using Elf32Half = uint16_t;
using Elf32Word = uint32_t;
using Elf32Sword = int32_t;
struct Elf32FileHeader
{
unsigned char e_ident[16];
Elf32Half e_type;
Elf32Half e_machine;
Elf32Word e_version;
Elf32Addr e_entry;
Elf32Off e_phoff;
Elf32Off e_shoff;
Elf32Word e_flags;
Elf32Half e_ehsize;
Elf32Half e_phentsize;
Elf32Half e_phnum;
Elf32Half e_shentsize;
Elf32Half e_shnum;
Elf32Half e_shstrndx;
};
struct Elf32SectionHeader
{
Elf32Word sh_name;
Elf32Word sh_type;
Elf32Word sh_flags;
Elf32Addr sh_addr;
Elf32Off sh_offset;
Elf32Word sh_size;
Elf32Word sh_link;
Elf32Word sh_info;
Elf32Word sh_addralign;
Elf32Word sh_entsize;
};
struct Elf32Symbol
{
Elf32Word st_name;
Elf32Addr st_value;
Elf32Word st_size;
unsigned char st_info;
unsigned char st_other;
Elf32Half st_shndx;
};
struct Elf32Relocation
{
Elf32Addr r_offset;
Elf32Word r_info;
};
struct Elf32RelocationA
{
Elf32Addr r_offset;
Elf32Word r_info;
Elf32Sword r_addend;
};
struct Elf32ProgramHeader
{
Elf32Word p_type;
Elf32Off p_offset;
Elf32Addr p_vaddr;
Elf32Addr p_paddr;
Elf32Word p_filesz;
Elf32Word p_memsz;
Elf32Word p_flags;
Elf32Word p_align;
};
using Elf64Addr = uint64_t;
using Elf64Off = uint64_t;
using Elf64Half = uint16_t;