elf.h

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#ifndef ELF_H
#define ELF_H
 
#include <stddef.h>
#include <stdint.h>
 
#define SHT_REL 0x9
#define R_SYM(val) ((val) >> 8)
#define R_TYPE(val) ((val) & 0xff)
#define ST_TYPE(i) ((i) & 0xf)
 
typedef uint32_t Elf_Addr;
typedef uint32_t Elf_Off;
typedef uint16_t Elf_Half;
typedef uint32_t Elf_Word;
typedef int32_t Elf_Sword;
 
// We define the Xword and Sxword types for ELF32 even though they don't exist
// in the spec for forwards compatibility with ELF64.
typedef uint32_t Elf_Xword;
typedef int32_t Elf_Sxword;
 
typedef struct ElfHeader_t {
  uint8_t ident[16];
  Elf_Half type;
  Elf_Half machine;
  Elf_Word version;
  Elf_Addr entry;
  Elf_Off phoff;
  Elf_Off shoff;
  Elf_Word flags;
  Elf_Half ehsize;
  Elf_Half phentsize;
  Elf_Half phnum;
  Elf_Half shentsize;
  Elf_Half shnum;
  Elf_Half shstrndx;
} __attribute__((packed)) ElfHeader_t;
 
typedef struct ElfSectionHeader_t {
  Elf_Word name;
  Elf_Word type;
  Elf_Xword flags;
  Elf_Addr addr;
  Elf_Off offset;
  Elf_Xword size;
  Elf_Word link;
  Elf_Word info;
  Elf_Xword addralign;
  Elf_Xword entsize;
} __attribute__((packed)) ElfSectionHeader_t;
 
typedef struct ElfSymbol_t {
  Elf_Word name;
  Elf_Addr value;
  Elf_Xword size;
  uint8_t info;
  uint8_t other;
  Elf_Half shndx;
} __attribute__((packed)) ElfSymbol_t;
 
typedef struct ElfRel_t {
  Elf_Addr offset;
  Elf_Xword info;
} __attribute__((packed)) ElfRel_t;
 
typedef struct Elf_t {
  uint8_t* buffer;
  ElfHeader_t* header;
  ElfSectionHeader_t* section_headers;
  ElfSymbol_t* symtab;
  size_t symtabsz;
  char* strtab;
  size_t strtabsz;
} Elf_t;
 
#define SYM_PTR(elf, sym) \
  ((uint32_t*)&(elf->buffer[sym->value + elf->section_headers[sym->shndx].offset]))
 
Elf_t* elf_create(uint8_t* buffer, size_t len);
ElfSymbol_t* elf_get_symbol(Elf_t* elf, const char* name);
uint8_t* elf_relptr(Elf_t* elf, ElfSymbol_t* sym, uint32_t ptr);
 
#endif