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// Copyright (c) 2012, Google Inc.

// All rights reserved.

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//     * Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

//     * Neither the name of Google Inc. nor the names of its

// contributors may be used to endorse or promote products derived from

// this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//

// elfutils.h: Utilities for dealing with ELF files.

//

#ifndef COMMON_LINUX_ELFUTILS_H_

#define COMMON_LINUX_ELFUTILS_H_

#include <elf.h>

#include <link.h>

#include <stdint.h>

#include "common/memory_allocator.h"

namespace google_breakpad {

// Traits classes so consumers can write templatized code to deal

// with specific ELF bits.

struct ElfClass32 {

  typedef Elf32_Addr Addr;

  typedef Elf32_Dyn Dyn;

  typedef Elf32_Ehdr Ehdr;

  typedef Elf32_Nhdr Nhdr;

  typedef Elf32_Phdr Phdr;

  typedef Elf32_Shdr Shdr;

  typedef Elf32_Half Half;

  typedef Elf32_Off Off;

  typedef Elf32_Sym Sym;

  typedef Elf32_Word Word;

  static const int kClass = ELFCLASS32;

  static const uint16_t kMachine = EM_386;

  static const size_t kAddrSize = sizeof(Elf32_Addr);

  static constexpr const char* kMachineName = "x86";

};

struct ElfClass64 {

  typedef Elf64_Addr Addr;

  typedef Elf64_Dyn Dyn;

  typedef Elf64_Ehdr Ehdr;

  typedef Elf64_Nhdr Nhdr;

  typedef Elf64_Phdr Phdr;

  typedef Elf64_Shdr Shdr;

  typedef Elf64_Half Half;

  typedef Elf64_Off Off;

  typedef Elf64_Sym Sym;

  typedef Elf64_Word Word;

  static const int kClass = ELFCLASS64;

  static const uint16_t kMachine = EM_X86_64;

  static const size_t kAddrSize = sizeof(Elf64_Addr);

  static constexpr const char* kMachineName = "x86_64";

};

bool IsValidElf(const void* elf_header);

int ElfClass(const void* elf_base);

// Attempt to find a section named |section_name| of type |section_type|

// in the ELF binary data at |elf_mapped_base|. On success, returns true

// and sets |*section_start| to point to the start of the section data,

// and |*section_size| to the size of the section's data.

bool FindElfSection(const void *elf_mapped_base,

                    const char *section_name,

                    uint32_t section_type,

                    const void **section_start,

                    size_t *section_size);

// Internal helper method, exposed for convenience for callers

// that already have more info.

template<typename ElfClass>

const typename ElfClass::Shdr*

FindElfSectionByName(const char* name,

                     typename ElfClass::Word section_type,

                     const typename ElfClass::Shdr* sections,

                     const char* section_names,

                     const char* names_end,

                     int nsection);

struct ElfSegment {

  const void* start;

  size_t size;

};

// Attempt to find all segments of type |segment_type| in the ELF

// binary data at |elf_mapped_base|. On success, returns true and fills

// |*segments| with a list of segments of the given type.

bool FindElfSegments(const void* elf_mapped_base,

                     uint32_t segment_type,

                     wasteful_vector<ElfSegment>* segments);

// Convert an offset from an Elf header into a pointer to the mapped

// address in the current process. Takes an extra template parameter

// to specify the return type to avoid having to dynamic_cast the

// result.

template<typename ElfClass, typename T>

const T*

GetOffset(const typename ElfClass::Ehdr* elf_header,

          typename ElfClass::Off offset);

// Read the value of DT_SONAME from the elf file mapped at |elf_base|. Returns

// true and fills |soname| with the result if found.

bool ElfFileSoNameFromMappedFile(const void* elf_base,

                                 char* soname,

                                 size_t soname_size);

}  // namespace google_breakpad

#endif  // COMMON_LINUX_ELFUTILS_H_