1
// SPDX-FileCopyrightText: 2019-2024 Connor McLaughlin <[email protected]>
2
// SPDX-License-Identifier: CC-BY-NC-ND-4.0
3

4
#pragma once
5

6
#include "common/heap_array.h"
7
#include "common/types.h"
8

9
#include <functional>
10
#include <string_view>
11

12
class Error;
13

14
class ELFFile
15
{
16
public:
17
  using DataArray = DynamicHeapArray<u8>;
18

19
  // ELF header constants
20
  static constexpr u8 EI_NIDENT = 16;
21
  static constexpr u16 ET_EXEC = 2;
22
  static constexpr u16 ET_DYN = 3;
23
  static constexpr u16 EM_MIPS = 8;
24
  static constexpr u16 SHN_UNDEF = 0;
25
  static constexpr u32 SHT_NULL = 0;
26
  static constexpr u32 SHT_PROGBITS = 1;
27
  static constexpr u32 SHT_SYMTAB = 2;
28
  static constexpr u32 SHT_STRTAB = 3;
29
  static constexpr u32 SHT_RELA = 4;
30
  static constexpr u32 SHT_HASH = 5;
31
  static constexpr u32 SHT_DYNAMIC = 6;
32
  static constexpr u32 SHT_NOTE = 7;
33
  static constexpr u32 SHT_NOBITS = 8;
34
  static constexpr u32 SHT_REL = 9;
35
  static constexpr u32 SHT_SHLIB = 10;
36
  static constexpr u32 SHT_DYNSYM = 11;
37
  static constexpr u32 SHT_NUM = 12;
38
  static constexpr u32 PT_NULL = 0;
39
  static constexpr u32 PT_LOAD = 1;
40
  static constexpr u32 PT_DYNAMIC = 2;
41
  static constexpr u32 PT_INTERP = 3;
42
  static constexpr u32 PT_NOTE = 4;
43
  static constexpr u32 PT_SHLIB = 5;
44
  static constexpr u32 PT_PHDR = 6;
45
  static constexpr u32 PT_TLS = 7;
46

47
  // ELF Header structure
48
  struct Elf32_Ehdr
49
  {
50
    u8 e_ident[EI_NIDENT]; // Magic number and other information
51
    u16 e_type;            // Object file type
52
    u16 e_machine;         // Architecture
53
    u32 e_version;         // Object file version
54
    u32 e_entry;           // Entry point virtual address
55
    u32 e_phoff;           // Program header table file offset
56
    u32 e_shoff;           // Section header table file offset
57
    u32 e_flags;           // Processor-specific flags
58
    u16 e_ehsize;          // ELF header size in bytes
59
    u16 e_phentsize;       // Program header table entry size
60
    u16 e_phnum;           // Program header table entry count
61
    u16 e_shentsize;       // Section header table entry size
62
    u16 e_shnum;           // Section header table entry count
63
    u16 e_shstrndx;        // Section header string table index
64
  };
65

66
  // Section header structure
67
  struct Elf32_Shdr
68
  {
69
    u32 sh_name;      // Section name (string tbl index)
70
    u32 sh_type;      // Section type
71
    u32 sh_flags;     // Section flags
72
    u32 sh_addr;      // Section virtual addr at execution
73
    u32 sh_offset;    // Section file offset
74
    u32 sh_size;      // Section size in bytes
75
    u32 sh_link;      // Link to another section
76
    u32 sh_info;      // Additional section information
77
    u32 sh_addralign; // Section alignment
78
    u32 sh_entsize;   // Entry size if section holds table
79
  };
80

81
  // Program header structure
82
  struct Elf32_Phdr
83
  {
84
    u32 p_type;
85
    u32 p_offset;
86
    u32 p_vaddr;
87
    u32 p_paddr;
88
    u32 p_filesz;
89
    u32 p_memsz;
90
    u32 p_flags;
91
    u32 p_align;
92
  };
93

94
public:
95
  ELFFile();
96
  ~ELFFile();
97

98
  static bool IsValidElfHeader(const std::span<const u8> data, Error* error = nullptr);
99
  static bool IsValidElfHeader(const Elf32_Ehdr& header, Error* error = nullptr);
100

101
  const Elf32_Ehdr& GetELFHeader() const;
102
  u32 GetEntryPoint() const;
103

104
  const Elf32_Shdr* GetSectionHeader(u32 index) const;
105
  std::string_view GetSectionName(const Elf32_Shdr& section) const;
106
  u32 GetSectionCount() const;
107

108
  const Elf32_Phdr* GetProgramHeader(u32 index) const;
109
  u32 GetProgramHeaderCount() const;
110

111
  bool Open(const char* path, Error* error);
112
  bool Open(DataArray data, Error* error);
113

114
  using LoadExecutableSectionCallback =
115
    std::function<bool(std::span<const u8> data, u32 dest_vaddr, u32 dest_size, Error* error)>;
116
  bool LoadExecutableSections(const LoadExecutableSectionCallback& callback, Error* error) const;
117

118
private:
119
  DataArray m_data;
120
};
121

122