chromium/base/debug/elf_reader.cc

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40284755): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif

#include "base/debug/elf_reader.h"

#include <arpa/inet.h>
#include <elf.h>
#include <string.h>

#include <optional>
#include <string_view>

#include "base/bits.h"
#include "base/containers/span.h"
#include "base/hash/sha1.h"
#include "base/strings/safe_sprintf.h"
#include "build/build_config.h"

// NOTE: This code may be used in crash handling code, so the implementation
// must avoid dynamic memory allocation or using data structures which rely on
// dynamic allocation.

namespace base {
namespace debug {
namespace {

// See https://refspecs.linuxbase.org/elf/elf.pdf for the ELF specification.

#if __SIZEOF_POINTER__ == 4
using Ehdr = Elf32_Ehdr;
using Dyn = Elf32_Dyn;
using Half = Elf32_Half;
using Nhdr = Elf32_Nhdr;
using Word = Elf32_Word;
using Xword = Elf32_Word;
#else
Ehdr;
Dyn;
Half;
Nhdr;
Word;
Xword;
#endif

constexpr char kGnuNoteName[] = …;

// Returns a pointer to the header of the ELF binary mapped into memory, or a
// null pointer if the header is invalid. Here and below |elf_mapped_base| is a
// pointer to the start of the ELF image.
const Ehdr* GetElfHeader(const void* elf_mapped_base) { … }

}  // namespace

size_t ReadElfBuildId(const void* elf_mapped_base,
                      bool uppercase,
                      ElfBuildIdBuffer build_id) { … }

std::optional<std::string_view> ReadElfLibraryName(
    const void* elf_mapped_base) { … }

span<const Phdr> GetElfProgramHeaders(const void* elf_mapped_base) { … }

// Returns the offset to add to virtual addresses in the image to compute the
// mapped virtual address.
size_t GetRelocationOffset(const void* elf_mapped_base) { … }

}  // namespace debug
}  // namespace base