// -*- Mode: C++ -*-
//
// Copyright (C) 2015-2017 Red Hat, Inc.
//
// This file is part of the GNU Application Binary Interface Generic
// Analysis and Instrumentation Library (libabigail).  This library is
// free software; you can redistribute it and/or modify it under the
// terms of the GNU Lesser General Public License as published by the
// Free Software Foundation; either version 3, or (at your option) any
// later version.

// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Lesser Public License for more details.

// You should have received a copy of the GNU Lesser General Public
// License along with this program; see the file COPYING-LGPLV3.  If
// not, see <http://www.gnu.org/licenses/>.
//
// Author: Sinny Kumari

/// @file

/// This program compares the ABIs of binaries inside two packages.
///
/// For now, the supported package formats are Deb and RPM, but
/// support for other formats would be greatly appreciated.
///
/// The program takes the two packages to compare as well as their
/// associated debug info packages.
///
/// The program extracts the content of the two packages into a
/// temporary directory , looks for the ELF binaries in there,
/// compares their ABIs and emit a report about the changes.
/// As this program uses libpthread to perform several tasks
/// concurrently, here is a coarse grain description of the sequence
/// of actions performed, including where things are done
/// concurrently.
///
/// (steps 1/ and 2/ are performed concurrently.  Then steps 3/ and 4/
/// are performed in sequence)
///
/// 1/ the first package and its ancillary packages (debug info and
/// devel packages) are extracted concurrently.
/// There is one thread per package being extracted.  So if there are
/// 3 thread packages (one package, one debug info package and one
/// devel package), then there are 3 threads to extracts them.  Then
/// when the extracting is done, another thread performs the analysis
/// of th1 extracted content.
///
/// 2/ A similar thing is done for the second package.
///
/// 3/ comparisons are performed concurrently.
///
/// 4/ the reports are then emitted to standard output, always in the same
/// order.

// For package configuration macros.
#include "config.h"

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <vector>
#include <fts.h>
#include <algorithm>
#include <map>
#include <assert.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <elf.h>
#include <elfutils/libdw.h>

#include "abg-workers.h"
#include "abg-config.h"
#include "abg-tools-utils.h"
#include "abg-comparison.h"
#include "abg-suppression.h"
#include "abg-dwarf-reader.h"

using std::cout;
using std::cerr;
using std::string;
using std::ostream;
using std::vector;
using std::map;
using std::ostringstream;
using std::tr1::shared_ptr;
using std::tr1::dynamic_pointer_cast;
using abigail::workers::task;
using abigail::workers::task_sptr;
using abigail::workers::queue;
using abigail::tools_utils::maybe_get_symlink_target_file_path;
using abigail::tools_utils::file_exists;
using abigail::tools_utils::is_dir;
using abigail::tools_utils::emit_prefix;
using abigail::tools_utils::check_file;
using abigail::tools_utils::ensure_dir_path_created;
using abigail::tools_utils::guess_file_type;
using abigail::tools_utils::string_ends_with;
using abigail::tools_utils::file_type;
using abigail::tools_utils::make_path_absolute;
using abigail::tools_utils::base_name;
using abigail::tools_utils::gen_suppr_spec_from_headers;
using abigail::tools_utils::get_default_system_suppression_file_path;
using abigail::tools_utils::get_default_user_suppression_file_path;
using abigail::tools_utils::load_default_system_suppressions;
using abigail::tools_utils::load_default_user_suppressions;
using abigail::tools_utils::abidiff_status;
using abigail::ir::corpus_sptr;
using abigail::comparison::diff_context;
using abigail::comparison::diff_context_sptr;
using abigail::comparison::compute_diff;
using abigail::comparison::corpus_diff_sptr;
using abigail::suppr::suppression_sptr;
using abigail::suppr::suppressions_type;
using abigail::suppr::read_suppressions;
using abigail::dwarf_reader::read_context_sptr;
using abigail::dwarf_reader::create_read_context;
using abigail::dwarf_reader::get_soname_of_elf_file;
using abigail::dwarf_reader::get_type_of_elf_file;
using abigail::dwarf_reader::read_corpus_from_elf;

/// The options passed to the current program.
class options
{
  options();

public:
  string	wrong_option;
  string	wrong_arg;
  string	prog_name;
  bool		display_usage;
  bool		display_version;
  bool		missing_operand;
  bool		nonexistent_file;
  bool		abignore;
  bool		parallel;
  string	package1;
  string	package2;
  string	debug_package1;
  string	debug_package2;
  string	devel_package1;
  string	devel_package2;
  size_t	num_workers;
  bool		verbose;
  bool		drop_private_types;
  bool		show_relative_offset_changes;
  bool		no_default_suppression;
  bool		keep_tmp_files;
  bool		compare_dso_only;
  bool		show_linkage_names;
  bool		show_redundant_changes;
  bool		show_harmless_changes;
  bool		show_locs;
  bool		show_added_syms;
  bool		show_added_binaries;
  bool		fail_if_no_debug_info;
  bool		show_identical_binaries;
  vector<string> suppression_paths;

  options(const string& program_name)
    : prog_name(program_name),
      display_usage(),
      display_version(),
      missing_operand(),
      nonexistent_file(),
      abignore(true),
      parallel(true),
      verbose(false),
      drop_private_types(false),
      show_relative_offset_changes(true),
      no_default_suppression(),
      keep_tmp_files(),
      compare_dso_only(),
      show_linkage_names(true),
      show_redundant_changes(),
      show_harmless_changes(),
      show_locs(true),
      show_added_syms(true),
      show_added_binaries(true),
      fail_if_no_debug_info(),
      show_identical_binaries()
  {
    // set num_workers to the default number of threads of the
    // underlying maching.  This is the default value for the number
    // of workers to use in workers queues throughout the code.
    num_workers = abigail::workers::get_number_of_threads();
  }
};

/// Abstract ELF files from the packages which ABIs ought to be
/// compared
class elf_file
{
private:
  elf_file();

public:
  string				path;
  string				name;
  string				soname;
  off_t 				size;
  abigail::dwarf_reader::elf_type	type;

  /// The path to the elf file.
  ///
  /// @param path the path to the elf file.
  elf_file(const string& path)
    : path(path)
   {
     abigail::tools_utils::base_name(path, name);
     get_soname_of_elf_file(path, soname);
     get_type_of_elf_file(path, type);
     struct stat estat;
     stat(path.c_str(), &estat);
     size = estat.st_size;
  }
};

/// A convenience typedef for a shared pointer to elf_file.
typedef shared_ptr<elf_file> elf_file_sptr;

/// Abstract the result of comparing two packages.
///
/// This contains the the paths of the set of added binaries, removed
/// binaries, and binaries whic ABI changed.
struct abi_diff
{
  vector<elf_file_sptr> added_binaries;
  vector<elf_file_sptr> removed_binaries;
  vector<string> changed_binaries;

  /// Test if the current diff carries changes.
  ///
  /// @return true iff the current diff carries changes.
  bool
  has_changes()
  {
    return (!added_binaries.empty()
	    || !removed_binaries.empty()
	    ||!changed_binaries.empty());
  }
};

class package;

/// Convenience typedef for a shared pointer to a @ref package.
typedef shared_ptr<package> package_sptr;

/// Abstracts a package.
class package
{
public:

  /// The kind of package we are looking at.
  enum kind
  {
    /// Main package. Contains binaries to ABI-compare.
    KIND_MAIN = 0,
    /// Devel package.  Contains public headers files in which public
    /// types are defined.
    KIND_DEVEL,
    /// Debug info package.  Contains the debug info for the binaries
    /// int he main packge.
    KIND_DEBUG_INFO,
    /// Source package.  Contains the source of the binaries in the
    /// main package.
    KIND_SRC
  };

private:
  string				path_;
  string				extracted_dir_path_;
  abigail::tools_utils::file_type	type_;
  kind					kind_;
  map<string, elf_file_sptr>		path_elf_file_sptr_map_;
  package_sptr				debug_info_package_;
  package_sptr				devel_package_;
  suppressions_type			private_types_suppressions_;

public:
  /// Constructor for the @ref package type.
  ///
  /// @param path the path to the package.
  ///
  /// @parm dir the temporary directory where to extract the content
  /// of the package.
  ///
  /// @param pkg_kind the kind of package.
  package(const string&			path,
	  const string&			dir,
          kind					pkg_kind = package::KIND_MAIN)
    : path_(path),
      kind_(pkg_kind)
  {
    type_ = guess_file_type(path);
    if (type_ == abigail::tools_utils::FILE_TYPE_DIR)
      extracted_dir_path_ = path;
    else
      extracted_dir_path_ = extracted_packages_parent_dir() + "/" + dir;
  }

  /// Getter of the path of the package.
  ///
  /// @return the path of the package.
  const string&
  path() const
  {return path_;}

  /// Setter of the path of the package.
  ///
  /// @param s the new path.
  void
  path(const string& s)
  {path_ = s;}

  /// Getter for the path to the root dir where the packages are
  /// extracted.
  ///
  /// @return the path to the root dir where the packages are
  /// extracted.
  static const string&
  extracted_packages_parent_dir();

  /// Getter for the path to the directory where the packages are
  /// extracted for the current thread.
  ///
  /// @return the path to the directory where the packages are
  /// extracted for the current thread.
  const string&
  extracted_dir_path() const
  {return extracted_dir_path_;}

  /// Setter for the path to the directory where the packages are
  /// extracted for the current thread.
  ///
  /// @param p the new path.
  void
  extracted_dir_path(const string& p)
  {extracted_dir_path_ = p;}

  /// Getter for the file type of the current package.
  ///
  /// @return the file type of the current package.
  abigail::tools_utils::file_type
  type() const
  {return type_;}

  /// Setter for the file type of the current package.
  ///
  /// @param t the new file type.
  void type(abigail::tools_utils::file_type t)
  {type_ = t;}

  /// Get the package kind
  ///
  /// @return the package kind
  kind
  get_kind() const
  {return kind_;}

  /// Set the package kind
  ///
  /// @param k the package kind.
  void
  set_kind(kind k)
  {kind_ = k;}

  /// Getter for the path <-> elf_file map.
  ///
  /// @return the the path <-> elf_file map.
  const map<string, elf_file_sptr>&
  path_elf_file_sptr_map() const
  {return path_elf_file_sptr_map_;}

  /// Getter for the path <-> elf_file map.
  ///
  /// @return the the path <-> elf_file map.
  map<string, elf_file_sptr>&
  path_elf_file_sptr_map()
  {return path_elf_file_sptr_map_;}

  /// Getter for the debug info package associated to the current
  /// package.
  ///
  /// @return the debug info package associated to the current
  /// package.
  const shared_ptr<package>&
  debug_info_package() const
  {return debug_info_package_;}

  /// Setter for the debug info package associated to the current
  /// package.
  ///
  /// @param p the new debug info package.
  void
  debug_info_package(const shared_ptr<package> p)
  {debug_info_package_ = p;}

  /// Getter for the devel package associated to the current package.
  ///
  /// @return the devel package associated to the current package.
  const package_sptr&
  devel_package() const
  {return devel_package_;}

  /// Setter of the devel package associated to the current package.
  ///
  /// @param p the new devel package associated to the current package.
  void
  devel_package(const package_sptr& p)
  {devel_package_ = p;}

  /// Getter of the specifications to suppress change reports about
  /// private types.
  ///
  /// @return the vector of specifications to suppress change reports
  /// about private types.
  const suppressions_type&
  private_types_suppressions() const
  {return private_types_suppressions_;}

  /// Getter of the specifications to suppress change reports about
  /// private types.
  ///
  /// @return the vector of specifications to suppress change reports
  /// about private types.
  suppressions_type&
  private_types_suppressions()
  {return private_types_suppressions_;}

  /// Erase the content of the temporary extraction directory that has
  /// been populated by the @ref extract_package() function;
  ///
  /// @param opts the options passed to the current program.
  void
  erase_extraction_directory(const options &opts) const
  {
    if (type() == abigail::tools_utils::FILE_TYPE_DIR)
      // If we are comparing two directories, do not erase the
      // directory as it was provided by the user; it's not a
      // temporary directory we created ourselves.
      return;

    if (opts.verbose)
      emit_prefix("abipkgdiff", cerr)
	<< "Erasing temporary extraction directory "
	<< extracted_dir_path()
	<< " ...";

    string cmd = "rm -rf " + extracted_dir_path();
    if (system(cmd.c_str()))
      {
	if (opts.verbose)
	  emit_prefix("abipkgdiff", cerr) << " FAILED\n";
      }
    else
      {
	if (opts.verbose)
	  emit_prefix("abipkgdiff", cerr) << " DONE\n";
      }
  }

  /// Erase the content of all the temporary extraction directories.
  ///
  /// @param opts the options passed to the current program.
  void
  erase_extraction_directories(const options &opts) const
  {
    erase_extraction_directory(opts);
    if (debug_info_package())
      debug_info_package()->erase_extraction_directory(opts);
    if (devel_package())
      devel_package()->erase_extraction_directory(opts);
  }
}; // end class package.

/// Arguments passed to the comparison tasks.
struct compare_args
{
  const elf_file	elf1;
  const string&	debug_dir1;
  const suppressions_type&	private_types_suppr1;
  const elf_file	elf2;
  const string&	debug_dir2;
  const suppressions_type&	private_types_suppr2;
  const options&	opts;

  /// Constructor for compare_args, which is used to pass
  /// information to the comparison threads.
  ///
  /// @param elf1 the first elf file to consider.
  ///
  /// @param debug_dir1 the directory where the debug info file for @p
  /// elf1 is stored.
  ///
  /// @param elf2 the second elf file to consider.
  ///
  /// @param debug_dir2 the directory where the debug info file for @p
  /// elf2 is stored.
  ///
  /// @param opts the options the current program has been called with.
  compare_args(const elf_file &elf1, const string& debug_dir1,
	       const suppressions_type& priv_types_suppr1,
	       const elf_file &elf2, const string& debug_dir2,
	       const suppressions_type& priv_types_suppr2,
	       const options& opts)
    : elf1(elf1), debug_dir1(debug_dir1),
      private_types_suppr1(priv_types_suppr1),
      elf2(elf2), debug_dir2(debug_dir2),
      private_types_suppr2(priv_types_suppr2),
      opts(opts)
  {}
}; // end struct compare_args

/// A convenience typedef for arguments passed to the comparison workers.
typedef shared_ptr<compare_args> compare_args_sptr;

static bool extract_package_and_map_its_content(package &pkg,
						options &opts);

/// Getter for the path to the parent directory under which packages
/// extracted by the current thread are placed.
///
/// @return the path to the parent directory under which packages
/// extracted by the current thread are placed.
const string&
package::extracted_packages_parent_dir()
{
  // I tried to declare this in thread-local storage, but GCC 4.4.7
  // won't let me.  So for now, I am just making it static.  I'll deal
  // with this later when I have to.

  //static __thread string p;
  static string p;

  if (p.empty())
    {
      const char *cachedir = getenv("XDG_CACHE_HOME");

      if (cachedir != NULL)
        p = cachedir;
      else
        {
	  const char* s = getenv("HOME");
	  if (s != NULL)
	    p = s;
	  if (p.empty())
	    {
	      s = getenv("TMPDIR");
	      if (s != NULL)
		p = s;
	      else
		p = "/tmp";
	    }
	  p += "/.cache/libabigail";
        }

      // Create the cache directory if it doesn't exist
      bool cache_dir_is_created = ensure_dir_path_created(p);
      assert(cache_dir_is_created);

      string libabigail_tmp_dir_template = p;
      libabigail_tmp_dir_template += "/abipkgdiff-tmp-dir-XXXXXX";

      if (!mkdtemp(const_cast<char*>(libabigail_tmp_dir_template.c_str())))
	abort();

      p = libabigail_tmp_dir_template;
    }

  return p;
}

/// A convenience typedef for shared_ptr of package.
typedef shared_ptr<package> package_sptr;

/// Show the usage of this program.
///
/// @param prog_name the name of the program.
///
/// @param out the output stream to emit the usage to .
static void
display_usage(const string& prog_name, ostream& out)
{
  emit_prefix(prog_name, out)
    << "usage: " << prog_name << " [options] <package1> <package2>\n"
    << " where options can be:\n"
    << " --debug-info-pkg1|--d1 <path>  path of debug-info package of package1\n"
    << " --debug-info-pkg2|--d2 <path>  path of debug-info package of package2\n"
    << " --devel-pkg1|--devel1 <path>   path of devel package of pakage1\n"
    << " --devel-pkg2|--devel2 <path>   path of devel package of pakage1\n"
    << " --drop-private-types  drop private types from "
    "internal representation\n"
    << " --no-default-suppression       don't load any default "
       "suppression specifications\n"
    << " --suppressions|--suppr <path>  specify supression specification path\n"
    << " --keep-tmp-files               don't erase created temporary files\n"
    << " --dso-only                     compare shared libraries only\n"
    << " --no-linkage-name		do not display linkage names of "
    "added/removed/changed\n"
    << " --redundant                    display redundant changes\n"
    << " --harmless                     display the harmless changes\n"
    << " --no-show-locs                 do not show location information\n"
    << " --no-show-relative-offset-changes  do not show relative"
    " offset changes\n"
    << " --no-added-syms                do not display added functions or variables\n"
    << " --no-added-binaries            do not display added binaries\n"
    << " --no-abignore                  do not look for *.abignore files\n"
    << " --no-parallel                  do not execute in parallel\n"
    << " --fail-no-dbg                  fail if no debug info was found\n"
    << " --show-identical-binaries      show the names of identical binaries\n"
    << " --verbose                      emit verbose progress messages\n"
    << " --help|-h                      display this help message\n"
    << " --version|-v                   display program version information"
    " and exit\n";
}

#ifdef WITH_RPM

/// Extract an RPM package.
///
/// @param package_path the path to the package to extract.
///
/// @param extracted_package_dir_path the path where to extract the
/// package to.
///
/// @param opts the options passed to the current program.
///
/// @return true upon successful completion, false otherwise.
static bool
extract_rpm(const string& package_path,
	    const string& extracted_package_dir_path,
	    const options &opts)
{
  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Extracting package "
      << package_path
      << " to "
      << extracted_package_dir_path
      << " ...";

  string cmd = "test -d " +
    extracted_package_dir_path +
    " && rm -rf " + extracted_package_dir_path;

  if (system(cmd.c_str()))
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << "command " << cmd << " FAILED\n";
    }

  cmd = "mkdir -p " + extracted_package_dir_path + " && cd " +
    extracted_package_dir_path + " && rpm2cpio " + package_path +
    " | cpio -dium --quiet";

  if (system(cmd.c_str()))
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << " FAILED\n";
      return false;
    }

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr) << " DONE\n";

  return true;
}

#endif // WITH_RPM

#ifdef WITH_DEB

/// Extract a Debian binary package.
///
/// @param package_path the path to the package to extract.
///
/// @param extracted_package_dir_path the path where to extract the
/// package to.
///
/// @param opts the options passed to the current program.
///
/// @return true upon successful completion, false otherwise.
static bool
extract_deb(const string& package_path,
	    const string& extracted_package_dir_path,
	    const options &opts)
{
  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Extracting package "
      << package_path
      << " to "
      << extracted_package_dir_path
      << " ...";

  string cmd = "test -d " +
    extracted_package_dir_path +
    " && rm -rf " + extracted_package_dir_path;

  if (system(cmd.c_str()))
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << "command "  << cmd <<  " FAILED\n";
    }

  cmd = "mkdir -p " + extracted_package_dir_path + " && dpkg -x " +
    package_path + " " + extracted_package_dir_path;

  if (system(cmd.c_str()))
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << " FAILED\n";
      return false;
    }

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr) << " DONE\n";

  return true;
}

#endif // WITH_DEB

#ifdef WITH_TAR

/// Extract a GNU Tar archive.
///
/// @param package_path the path to the archive to extract.
///
/// @param extracted_package_dir_path the path where to extract the
/// archive to.
///
/// @param opts the options passed to the current program.
///
/// @return true upon successful completion, false otherwise.
static bool
extract_tar(const string& package_path,
	    const string& extracted_package_dir_path,
	    const options &opts)
{
  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Extracting tar archive "
      << package_path
      << " to "
      << extracted_package_dir_path
      << " ...";

  string cmd = "test -d " +
    extracted_package_dir_path +
    " && rm -rf " + extracted_package_dir_path;

  if (system(cmd.c_str()))
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << "command " << cmd << " FAILED\n";
    }

  cmd = "mkdir -p " + extracted_package_dir_path + " && cd " +
    extracted_package_dir_path + " && tar -xf " + package_path;

  if (system(cmd.c_str()))
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << " FAILED\n";
      return false;
    }

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr) << " DONE\n";

  return true;
}

#endif // WITH_TAR

/// Erase the temporary directories created for the extraction of two
/// packages.
///
/// @param first_package the first package to consider.
///
/// @param opts the options passed to the current program.
///
/// @param second_package the second package to consider.
static void
erase_created_temporary_directories(const package& first_package,
				    const package& second_package,
				    const options &opts)
{
  first_package.erase_extraction_directories(opts);
  second_package.erase_extraction_directories(opts);
}

/// Erase the root of all the temporary directories created by the
/// current thread.
static void
erase_created_temporary_directories_parent(const options &opts)
{
  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Erasing temporary extraction parent directory "
      << package::extracted_packages_parent_dir()
      << " ...";

  string cmd = "rm -rf " + package::extracted_packages_parent_dir();
  if (system(cmd.c_str()))
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << "FAILED\n";
    }
  else
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr) << "DONE\n";
    }
}

/// Extract the content of a package.
///
/// @param package the package we are looking at.
///
/// @param opts the options passed to the current program.
static bool
extract_package(const package& package,
		const options &opts)
{
  switch(package.type())
    {
    case abigail::tools_utils::FILE_TYPE_RPM:
#ifdef WITH_RPM
      if (!extract_rpm(package.path(), package.extracted_dir_path(), opts))
        {
          emit_prefix("abipkgdiff", cerr)
	    << "Error while extracting package" << package.path() << "\n";
          return false;
        }
      return true;
#else
      emit_prefix("abipkgdiff", cerr)
	<< "Support for rpm hasn't been enabled.  Please consider "
      "enabling it at package configure time\n";
      return false;
#endif // WITH_RPM
      break;
    case abigail::tools_utils::FILE_TYPE_DEB:
#ifdef WITH_DEB
      if (!extract_deb(package.path(), package.extracted_dir_path(), opts))
        {
          emit_prefix("abipkgdiff", cerr)
	    << "Error while extracting package" << package.path() << "\n";
          return false;
        }
      return true;
#else
      emit_prefix("abipkgdiff", cerr)
	<< "Support for deb hasn't been enabled.  Please consider "
	"enabling it at package configure time\n";
      return false;
#endif // WITH_DEB
      break;

    case  abigail::tools_utils::FILE_TYPE_DIR:
      // The input package is just a directory that contains binaries,
      // there is nothing to extract.
      break;

    case abigail::tools_utils::FILE_TYPE_TAR:
#ifdef WITH_TAR
      if (!extract_tar(package.path(), package.extracted_dir_path(), opts))
        {
          emit_prefix("abipkgdiff", cerr)
	    << "Error while extracting GNU tar archive "
	    << package.path() << "\n";
          return false;
        }
      return true;
#else
      emit_prefix("abipkgdiff", cerr)
	<< "Support for GNU tar hasn't been enabled.  Please consider "
	"enabling it at package configure time\n";
      return false;
#endif // WITH_TAR
      break;

    default:
      return false;
    }
  return true;
}

/// Check that the suppression specification files supplied are
/// present.  If not, emit an error on stderr.
///
/// @param opts the options instance to use.
///
/// @return true if all suppression specification files are present,
/// false otherwise.
static bool
maybe_check_suppression_files(const options& opts)
{
  for (vector<string>::const_iterator i = opts.suppression_paths.begin();
       i != opts.suppression_paths.end();
       ++i)
    if (!check_file(*i, cerr, opts.prog_name))
      return false;

  return true;
}

/// Update the diff context from the @ref options data structure.
///
/// @param ctxt the diff context to update.
///
/// @param opts the instance of @ref options to consider.
static void
set_diff_context_from_opts(diff_context_sptr ctxt,
			   const options& opts)
{
  ctxt->default_output_stream(&cout);
  ctxt->error_output_stream(&cerr);
  ctxt->show_relative_offset_changes(opts.show_relative_offset_changes);
  ctxt->show_redundant_changes(opts.show_redundant_changes);
  ctxt->show_locs(opts.show_locs);
  ctxt->show_linkage_names(opts.show_linkage_names);
  ctxt->show_added_fns(opts.show_added_syms);
  ctxt->show_added_vars(opts.show_added_syms);
  ctxt->show_added_symbols_unreferenced_by_debug_info
    (opts.show_added_syms);

  if (!opts.show_harmless_changes)
    ctxt->switch_categories_off
      (abigail::comparison::ACCESS_CHANGE_CATEGORY
       | abigail::comparison::COMPATIBLE_TYPE_CHANGE_CATEGORY
       | abigail::comparison::HARMLESS_DECL_NAME_CHANGE_CATEGORY
       | abigail::comparison::NON_VIRT_MEM_FUN_CHANGE_CATEGORY
       | abigail::comparison::STATIC_DATA_MEMBER_CHANGE_CATEGORY
       | abigail::comparison::HARMLESS_ENUM_CHANGE_CATEGORY
       | abigail::comparison::HARMLESS_SYMBOL_ALIAS_CHANGE_CATEORY);

  suppressions_type supprs;
  for (vector<string>::const_iterator i = opts.suppression_paths.begin();
       i != opts.suppression_paths.end();
       ++i)
    read_suppressions(*i, supprs);
  ctxt->add_suppressions(supprs);
}

/// Compare the ABI two elf files, using their associated debug info.
///
/// The result of the comparison is emitted to standard output.
///
/// @param elf1 the first elf file to consider.
///
/// @param debug_dir1 the directory where the debug info file for @p
/// elf1 is stored.
/// The result of the comparison is saved to a global corpus map.
///
/// @param elf2 the second eld file to consider.
/// @args the list of argument sets used for comparison
///
/// @param debug_dir2 the directory where the debug info file for @p
/// elf2 is stored.
///
/// @param opts the options the current program has been called with.
///
/// @param env the environment encapsulating the entire comparison.
///
/// @param diff the shared pointer to be set to the result of the comparison.
///
/// @return the status of the comparison.
static abidiff_status
compare(const elf_file& elf1,
	const string&	debug_dir1,
	const suppressions_type& priv_types_supprs1,
	const elf_file& elf2,
	const string&	debug_dir2,
	const suppressions_type& priv_types_supprs2,
	const options&	opts,
	abigail::ir::environment_sptr	&env,
	corpus_diff_sptr	&diff,
	diff_context_sptr	&ctxt)
{
  char *di_dir1 = (char*) debug_dir1.c_str(),
	*di_dir2 = (char*) debug_dir2.c_str();

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Comparing the ABIs of file "
      << elf1.path
      << " and "
      << elf2.path
      << "...\n";

  abigail::dwarf_reader::status c1_status = abigail::dwarf_reader::STATUS_OK,
    c2_status = abigail::dwarf_reader::STATUS_OK;

  ctxt.reset(new diff_context);
  set_diff_context_from_opts(ctxt, opts);
  suppressions_type& supprs = ctxt->suppressions();
  bool files_suppressed = (file_is_suppressed(elf1.path, supprs)
			   ||file_is_suppressed(elf2.path, supprs));

  if (files_suppressed)
    {
      if (opts.verbose)
	emit_prefix("abipkgdiff", cerr)
	  << "  input file "
	  << elf1.path << " or " << elf2.path
	  << " has been suppressed by a suppression specification.\n"
	  << " Not reading any of them\n";
      return abigail::tools_utils::ABIDIFF_OK;
    }

  // Add the first private type suppressions set to the set of
  // suppressions.
  for (suppressions_type::const_iterator i = priv_types_supprs1.begin();
       i != priv_types_supprs1.end();
       ++i)
    supprs.push_back(*i);

  // Add the second private type suppressions set to the set of
  // suppressions.
  for (suppressions_type::const_iterator i = priv_types_supprs2.begin();
       i != priv_types_supprs2.end();
       ++i)
    supprs.push_back(*i);

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "  Reading file "
      << elf1.path
      << " ...\n";

  corpus_sptr corpus1;
  {
    read_context_sptr c = create_read_context(elf1.path, &di_dir1, env.get(),
					      /*load_all_types=*/false);
    add_read_context_suppressions(*c, priv_types_supprs1);
    corpus1 = read_corpus_from_elf(*c, c1_status);

    if (!(c1_status & abigail::dwarf_reader::STATUS_OK))
      {
	if (opts.verbose)
	  emit_prefix("abipkgdiff", cerr)
	    << "Could not read file '"
	    << elf1.path
	    << "' properly\n";
	return abigail::tools_utils::ABIDIFF_ERROR;
      }
  }

  if (opts.fail_if_no_debug_info
      && (c1_status & abigail::dwarf_reader::STATUS_DEBUG_INFO_NOT_FOUND))
    {
      emit_prefix("abipkgdiff", cerr) << "Could not find debug info file";
      if (di_dir1 && strcmp(di_dir1, ""))
	emit_prefix("abipkgdiff", cerr) << " under " << di_dir1 << "\n";
      else
	emit_prefix("abipkgdiff", cerr) << "\n";

      return abigail::tools_utils::ABIDIFF_ERROR;
    }

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << " DONE reading file "
      << elf1.path
      << "\n";

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "  Reading file "
      << elf2.path
      << " ...\n";

  corpus_sptr corpus2;
  {
    read_context_sptr c = create_read_context(elf2.path, &di_dir2, env.get(),
					      /*load_all_types=*/false);
    add_read_context_suppressions(*c, priv_types_supprs2);
    corpus2 = read_corpus_from_elf(*c, c2_status);

    if (!(c2_status & abigail::dwarf_reader::STATUS_OK))
      {
	if (opts.verbose)
	  emit_prefix("abipkgdiff", cerr)
	    << "Could not find the read file '"
	    << elf2.path
	    << "' properly\n";
	return abigail::tools_utils::ABIDIFF_ERROR;
      }
  }

  if (opts.fail_if_no_debug_info
      && (c2_status & abigail::dwarf_reader::STATUS_DEBUG_INFO_NOT_FOUND))
    {
      emit_prefix("abipkgdiff", cerr)
	<< "Could not find debug info file";
      if (di_dir1 && strcmp(di_dir2, ""))
	emit_prefix("abipkgdiff", cerr)
	  << " under " << di_dir2 << "\n";
      else
	emit_prefix("abipkgdiff", cerr) << "\n";

      return abigail::tools_utils::ABIDIFF_ERROR;
    }

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << " DONE reading file " << elf2.path << "\n";

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "  Comparing the ABIs of: \n"
      << "    " << elf1.path << "\n"
      << "    " << elf2.path << "\n";

  diff = compute_diff(corpus1, corpus2, ctxt);

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Comparing the ABIs of file "
      << elf1.path
      << " and "
      << elf2.path
      << " is DONE\n";

  abidiff_status s = abigail::tools_utils::ABIDIFF_OK;
  if (diff->has_net_changes())
    s |= abigail::tools_utils::ABIDIFF_ABI_CHANGE;
  if (diff->has_incompatible_changes())
    s |= abigail::tools_utils::ABIDIFF_ABI_INCOMPATIBLE_CHANGE;

  return s;
}

/// If devel packages were associated to the main package we are
/// looking at, use the names of the header files (extracted from the
/// package) to generate suppression specification to filter out types
/// that are not defined in those header files.
///
/// Filtering out types not defined in publi headers amounts to filter
/// out types that are deemed private to the package we are looking
/// at.
///
/// If the function succeeds, the generated private type suppressions
/// are available by invoking the
/// package::private_types_suppressions() accessor of the @p pkg
/// parameter.
///
/// @param pkg the main package we are looking at.
///
/// @param opts the options of the current program.
///
/// @return true iff suppression specifications were generated for
/// types private to the package.
static bool
maybe_create_private_types_suppressions(package& pkg, const options &opts)
{
  if (!pkg.private_types_suppressions().empty())
    return false;

  package_sptr devel_pkg = pkg.devel_package();
  if (!devel_pkg
      || !file_exists(devel_pkg->extracted_dir_path())
      || !is_dir(devel_pkg->extracted_dir_path()))
    return false;

  string headers_path = devel_pkg->extracted_dir_path();
  if (devel_pkg->type() == abigail::tools_utils::FILE_TYPE_RPM
      ||devel_pkg->type() == abigail::tools_utils::FILE_TYPE_DEB)
    // For RPM and DEB packages, header files are under the
    // /usr/include sub-directories.
    headers_path += "/usr/include";

  if (!is_dir(headers_path))
    return false;

  suppression_sptr suppr =
    gen_suppr_spec_from_headers(headers_path);

  if (suppr)
    {
      if (opts.drop_private_types)
	suppr->set_drops_artifact_from_ir(true);
      pkg.private_types_suppressions().push_back(suppr);
    }

  return suppr;
}

/// The task that performs the extraction of the content of a package
/// into a temporary directory.
///
/// Note that several instanaces of tasks can perform their jobs in
/// parallel.
class pkg_extraction_task : public task
{
  pkg_extraction_task();

public:
  package &pkg;
  const options &opts;
  bool is_ok;

  pkg_extraction_task(package &p, const options &o)
    : pkg(p), opts(o), is_ok(false)
  {}

  /// The job performed by the current task.  It's to be performed in
  /// parallel with other jobs.
  virtual void
  perform()
  {
    is_ok = extract_package(pkg, opts);
  }
}; //end class pkg_extraction_task

/// A convenience typedef for a shared pointer to @f pkg_extraction_task.
typedef shared_ptr<pkg_extraction_task> pkg_extraction_task_sptr;

/// The worker task which job is to prepares a package.
///
/// Preparing a package means:
///
/// 	1/ Extract the package and its ancillary packages.
///
/// 	2/ Analyze the extracted content, map that content so that we
/// 	determine what the ELF files to be analyze are.
class pkg_prepare_task : public abigail::workers::task
{
  pkg_prepare_task();

public:
  package &pkg;
  options &opts;
  bool is_ok;

  pkg_prepare_task(package &p, options &o)
    : pkg(p), opts(o), is_ok(false)
  {}

  /// The job performed by this task.
  virtual void
  perform()
  {
    is_ok = extract_package_and_map_its_content(pkg, opts);
  }
}; //end class pkg_prepare_task

/// A convenience typedef for a shared_ptr to @ref pkg_prepare_task
typedef shared_ptr<pkg_prepare_task> pkg_prepare_task_sptr;

/// The worker task which job is to compare two ELF binaries
class compare_task : public abigail::workers::task
{
public:

  compare_args_sptr args;
  abidiff_status status;
  ostringstream out;
  string pretty_output;

  compare_task()
    : status(abigail::tools_utils::ABIDIFF_OK)
  {}

  compare_task(const compare_args_sptr& a)
    : args(a),
      status(abigail::tools_utils::ABIDIFF_OK)
  {}

  /// The job performed by the task.
  ///
  /// This compares two ELF files, gets the resulting test report and
  /// stores it in an output stream.
  virtual void
  perform()
  {
    abigail::ir::environment_sptr env(new abigail::ir::environment);
    diff_context_sptr ctxt;
    corpus_diff_sptr diff;

    status |= compare(args->elf1, args->debug_dir1, args->private_types_suppr1,
		      args->elf2, args->debug_dir2, args->private_types_suppr2,
		      args->opts, env, diff, ctxt);

    if ((status & abigail::tools_utils::ABIDIFF_ABI_CHANGE)
	|| (args->opts.verbose && diff->has_changes()))
	diff->report(out, /*prefix=*/"  ");
    else
      {
	if (args->opts.show_identical_binaries)
	  out << "No ABI change detected\n";
      }

    if (status != abigail::tools_utils::ABIDIFF_OK)
      {
	string name = args->elf1.name;

	pretty_output =
	  string("================ changes of '") + name + "'===============\n"
	  + out.str()

	  + "================ end of changes of '"
	  + name + "'===============\n\n";
      }
  }
}; // end class compare_task

/// Convenience typedef for a shared_ptr of @ref compare_task.
typedef shared_ptr<compare_task> compare_task_sptr;

/// This function is sub-routine of create_maps_of_package_content.
///
/// It's called during the walking of the directory tree containing
/// the extracted content of package.  It's called with an entry of
/// that directory tree.
///
/// Depending on the kind of file this function is called on, it
/// updates the vector of paths of the directory and the set of
/// suppression paths found.
///
/// @param entry the directory entry to analyze.
///
/// @param opts the options of the current program.
///
/// @param paths out parameter.  This is the set of meaningful paths
/// of the current directory tree being analyzed.  These paths are
/// those that are going to be involved in ABI comparison.
static void
maybe_update_vector_of_package_content(const FTSENT *entry,
				       options &opts,
				       vector<string>& paths)
{
  if (entry == NULL
      || (entry->fts_info != FTS_F && entry->fts_info != FTS_SL)
      || entry->fts_info == FTS_ERR
      || entry->fts_info == FTS_NS)
    return;

  string path = entry->fts_path;
  maybe_get_symlink_target_file_path(path, path);

  if (guess_file_type(path) == abigail::tools_utils::FILE_TYPE_ELF)
    paths.push_back(path);
  else if (opts.abignore && string_ends_with(path, ".abignore"))
    opts.suppression_paths.push_back(path);
}

/// Create maps of the content of a given package.
///
/// The maps contain relevant metadata about the content of the
/// files.  These maps are used afterwards during the comparison of
/// the content of the package.  Note that the maps are stored in the
/// object that represents that package.
///
/// @param package the package to consider.
///
/// @param opts the options the current program has been called with.
///
/// @param true upon successful completion, false otherwise.
static bool
create_maps_of_package_content(package& package, options& opts)
{
  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Analyzing the content of package "
      << package.path()
      << " extracted to "
      << package.extracted_dir_path()
      << " ...\n";

  bool is_ok = false;
  char* paths[] = {const_cast<char*>(package.extracted_dir_path().c_str()), 0};

  FTS *file_hierarchy = fts_open(paths, FTS_LOGICAL|FTS_NOCHDIR, NULL);
  if (!file_hierarchy)
    return is_ok;

  vector<string> elf_file_paths;
  FTSENT *entry;
  while ((entry = fts_read(file_hierarchy)))
    maybe_update_vector_of_package_content(entry, opts, elf_file_paths);

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << "Found " << elf_file_paths.size() << " files in "
      << package.extracted_dir_path() << "\n";

  for (vector<string>::const_iterator file = elf_file_paths.begin();
       file != elf_file_paths.end();
       ++file)
    {
      elf_file_sptr e (new elf_file(*file));
      if (opts.compare_dso_only)
	{
	  if (e->type != abigail::dwarf_reader::ELF_TYPE_DSO)
	    {
	      if (opts.verbose)
		emit_prefix("abipkgdiff", cerr)
		  << "skipping non-DSO file " << e->path << "\n";
	      continue;
	    }
	}
      else
	{
	  if (e->type != abigail::dwarf_reader::ELF_TYPE_DSO
	      && e->type != abigail::dwarf_reader::ELF_TYPE_EXEC
              && e->type != abigail::dwarf_reader::ELF_TYPE_PI_EXEC)
	    {
	      if (opts.verbose)
		emit_prefix("abipkgdiff", cerr)
		  << "skipping non-DSO non-executable file " << e->path << "\n";
	      continue;
	    }
	}

      if (e->soname.empty())
	package.path_elf_file_sptr_map()[e->name] = e;
      else
	package.path_elf_file_sptr_map()[e->soname] = e;
    }

  if (opts.verbose)
    emit_prefix("abipkgdiff", cerr)
      << " Analysis of " << package.path() << " DONE\n";

  is_ok = true;

  return is_ok;
}

/// Extract the content of a package (and its ancillary packages) and
/// map its content.
///
/// First, the content of the package and its ancillary packages are
/// extracted, in parallel.
///
/// Then, after that extraction is done, the content of the package if
/// walked and analyzed.
///
/// @param pkg the package to extract and to analyze.
///
/// @param opts the options of the current program.
///
/// @return true iff the extraction and analyzing went well.
static bool
extract_package_and_map_its_content(package &pkg, options &opts)
{

  pkg_extraction_task_sptr main_pkg_extraction;
  pkg_extraction_task_sptr dbg_extraction;
  pkg_extraction_task_sptr devel_extraction;

  size_t NUM_EXTRACTIONS = 3;

  main_pkg_extraction.reset(new pkg_extraction_task(pkg, opts));

  if (package_sptr dbg_pkg = pkg.debug_info_package())
    dbg_extraction.reset(new pkg_extraction_task(*dbg_pkg, opts));

  if (package_sptr devel_pkg = pkg.devel_package())
    devel_extraction.reset(new pkg_extraction_task(*devel_pkg, opts));

  size_t num_workers = (opts.parallel
			? std::min(opts.num_workers, NUM_EXTRACTIONS)
			: 1);
  abigail::workers::queue extraction_queue(num_workers);

  // Perform the extraction of the 3 packages in parallel.
  extraction_queue.schedule_task(dbg_extraction);
  extraction_queue.schedule_task(main_pkg_extraction);
  extraction_queue.schedule_task(devel_extraction);

  // Wait for the extraction to be done.
  extraction_queue.wait_for_workers_to_complete();

  // Analyze and map the content of the extracted package.
  bool is_ok = false;
  if (main_pkg_extraction->is_ok)
    is_ok = create_maps_of_package_content(pkg, opts);

  if (is_ok)
    maybe_create_private_types_suppressions(pkg, opts);

  return is_ok;
}

/// Extract the two packages (and their ancillary packages) and
/// analyze their content, so that we later know what files from the
/// first package to compare against what files from the second
/// package.
///
/// Note that preparing the first package and its ancillary packages
/// happens in parallel with preparing the second package and its
/// ancillary packages.  The function then waits for the two
/// preparations to complete before returning.
///
/// @param first_package the first package to consider.
///
/// @param second_package the second package to consider.
///
/// @param opts the options of the current program.
///
/// @return true iff the preparation went well.
static bool
prepare_packages(package &first_package, package &second_package, options &opts)
{
  pkg_prepare_task_sptr first_pkg_prepare;
  pkg_prepare_task_sptr second_pkg_prepare;
  size_t NUM_PREPARATIONS = 2;

  first_pkg_prepare.reset(new pkg_prepare_task(first_package, opts));
  second_pkg_prepare.reset(new pkg_prepare_task(second_package, opts));

  size_t num_workers = (opts.parallel
			? std::min(opts.num_workers, NUM_PREPARATIONS)
			: 1);
  abigail::workers::queue preparation_queue(num_workers);

  preparation_queue.schedule_task(first_pkg_prepare);
  preparation_queue.schedule_task(second_pkg_prepare);

  preparation_queue.wait_for_workers_to_complete();

  return first_pkg_prepare->is_ok && second_pkg_prepare->is_ok;
}

/// Compare the added sizes of an ELF pair (specified by a comparison
/// task that compares two ELF files) against the added sizes of a
/// second ELF pair.
///
/// Larger filesize strongly raises the possibility of larger debug-info,
/// hence longer diff time. For a package containing several relatively
/// large and small ELFs, it is often more efficient to start working on
/// the larger ones first. This function is used to order the pairs by
/// size, starting from the largest.
///
/// @param t1 the first comparison task that compares a pair of ELF
/// files.
///
/// @param t2 the second comparison task that compares a pair of ELF
/// files.
///
/// @return true if @p task1 is greater than @p task2.
bool
elf_size_is_greater(const task_sptr &task1,
		    const task_sptr &task2)
{
  compare_task_sptr t1 = dynamic_pointer_cast<compare_task>(task1);
  compare_task_sptr t2 = dynamic_pointer_cast<compare_task>(task2);

  off_t s1 = t1->args->elf1.size + t1->args->elf2.size;
  off_t s2 = t2->args->elf1.size + t2->args->elf2.size;

  return s1 > s2;
}

/// This type is used to notify the calling thread that the comparison
/// of two ELF files is done.
class comparison_done_notify : public abigail::workers::queue::task_done_notify
{
  comparison_done_notify();

public:
  abi_diff& diff;
  abidiff_status status;

  comparison_done_notify(abi_diff &d)
    : diff(d),
      status(abigail::tools_utils::ABIDIFF_OK)
  {}

  /// This operator is invoked by the worker queue whenever a
  /// comparison task is done.
  ///
  /// The operator collects the status of the job of the task and also
  /// updates the the count of binaries that have ABI changes.
  ///
  /// @param task_done the task that is done.
  virtual void
  operator()(const task_sptr& task_done)
  {
    compare_task_sptr comp_task = dynamic_pointer_cast<compare_task>(task_done);
    assert(comp_task);

    status |= comp_task->status;

    if (status != abigail::tools_utils::ABIDIFF_OK)
      {
	string name = comp_task->args->elf1.name;

	if (status & abigail::tools_utils::ABIDIFF_ABI_CHANGE)
	  diff.changed_binaries.push_back(name);
      }
  }
}; // end struct comparison_done_notify

/// Erase the temporary directories that might have been created while
/// handling two packages, unless the user asked to keep the temporary
/// directories around.
///
/// @param first_package the first package to consider.
///
/// @param second_package the second package to consider.
///
/// @param opts the options passed to the program.
static void
maybe_erase_temp_dirs(package& first_package, package& second_package,
		      options& opts)
{
  if (opts.keep_tmp_files)
    return;

  erase_created_temporary_directories(first_package, second_package, opts);
  erase_created_temporary_directories_parent(opts);
}

/// Compare the ABI of two packages
///
/// @param first_package the first package to consider.
///
/// @param second_package the second package to consider.
///
/// @param options the options the current program has been called
/// with.
///
/// @param diff out parameter.  If this function returns true, then
/// this parameter is set to the result of the comparison.
///
/// @param opts the options of the current program.
///
/// @return the status of the comparison.
static abidiff_status
compare(package& first_package, package& second_package,
	abi_diff& diff, options& opts)
{
  // Prepare (extract and analyze the contents) the packages and their
  // ancillary packages.
  //
  // Note that the package preparations happens in parallel.
  if (!prepare_packages(first_package, second_package, opts))
    {
      maybe_erase_temp_dirs(first_package, second_package, opts);
      return abigail::tools_utils::ABIDIFF_ERROR;
    }

  // Setting debug-info path of libraries
  string debug_dir1, debug_dir2, relative_debug_path = "/usr/lib/debug/";
  if (first_package.debug_info_package()
      && second_package.debug_info_package())
    {
      debug_dir1 =
	first_package.debug_info_package()->extracted_dir_path() +
	relative_debug_path;
      if (second_package.debug_info_package())
	debug_dir2 =
	  second_package.debug_info_package()->extracted_dir_path() +
	  relative_debug_path;
    }

  abidiff_status status = abigail::tools_utils::ABIDIFF_OK;

  abigail::workers::queue::tasks_type compare_tasks;

  for (map<string, elf_file_sptr>::iterator it =
	 first_package.path_elf_file_sptr_map().begin();
       it != first_package.path_elf_file_sptr_map().end();
       ++it)
    {
      map<string, elf_file_sptr>::iterator iter =
	second_package.path_elf_file_sptr_map().find(it->first);

      if (iter != second_package.path_elf_file_sptr_map().end()
	  && (iter->second->type == abigail::dwarf_reader::ELF_TYPE_DSO
	      || iter->second->type == abigail::dwarf_reader::ELF_TYPE_EXEC
              || iter->second->type == abigail::dwarf_reader::ELF_TYPE_PI_EXEC))
	{
	  compare_args_sptr args
	    (new compare_args(*it->second,
			      debug_dir1,
			      first_package.private_types_suppressions(),
			      *iter->second,
			      debug_dir2,
			      second_package.private_types_suppressions(),
			      opts));

	  compare_task_sptr t(new compare_task(args));
	  compare_tasks.push_back(t);

	  second_package.path_elf_file_sptr_map().erase(iter);
	}
      else
	{
	  diff.removed_binaries.push_back(it->second);
	  status |= abigail::tools_utils::ABIDIFF_ABI_INCOMPATIBLE_CHANGE;
	  status |= abigail::tools_utils::ABIDIFF_ABI_CHANGE;
	}
    }

  if (compare_tasks.empty())
    {
      maybe_erase_temp_dirs(first_package, second_package, opts);
      return abigail::tools_utils::ABIDIFF_OK;
    }

  // Larger elfs are processed first, since it's usually safe to assume
  // their debug-info is larger as well, but the results are still
  // in a map ordered by looked up in elf.name order.
  std::sort(compare_tasks.begin(), compare_tasks.end(), elf_size_is_greater);

  // There's no reason to spawn more workers than there are ELF pairs
  // to be compared.
  size_t num_workers = (opts.parallel
			? std::min(opts.num_workers, compare_tasks.size())
			: 1);
  assert(num_workers >= 1);

  comparison_done_notify notifier(diff);
  abigail::workers::queue comparison_queue(num_workers, notifier);

  // Compare all the binaries, in parallel and then wait for the
  // comparisons to complete.
  comparison_queue.schedule_tasks(compare_tasks);
  comparison_queue.wait_for_workers_to_complete();

  // Get the set of comparison tasks that were perform and sort them.
  queue::tasks_type& done_tasks = comparison_queue.get_completed_tasks();
  std::sort(done_tasks.begin(), done_tasks.end(), elf_size_is_greater);

  // Print the reports of the comparison to standard output.
  for (queue::tasks_type::const_iterator i = done_tasks.begin();
       i != done_tasks.end();
       ++i)
    {
      compare_task_sptr t = dynamic_pointer_cast<compare_task>(*i);
      cout << t->pretty_output;
    }

  // Update the count of added binaries.
  for (map<string, elf_file_sptr>::iterator it =
	 second_package.path_elf_file_sptr_map().begin();
       it != second_package.path_elf_file_sptr_map().end();
       ++it)
    diff.added_binaries.push_back(it->second);

  // Print information about removed binaries on standard output.
  if (diff.removed_binaries.size())
    {
      cout << "Removed binaries:\n";
      for (vector<elf_file_sptr>::iterator it = diff.removed_binaries.begin();
	   it != diff.removed_binaries.end(); ++it)
	{
	  cout << "  " << (*it)->name << ", ";
	  string soname;
	  get_soname_of_elf_file((*it)->path, soname);
	  if (!soname.empty())
	    cout << "SONAME: " << soname;
	  else
	    cout << "no SONAME";
	  cout << "\n";
	}
    }

  // Print information about added binaries on standard output.
  if (opts.show_added_binaries && diff.added_binaries.size())
    {
      cout << "Added binaries:\n";
      for (vector<elf_file_sptr>::iterator it = diff.added_binaries.begin();
	   it != diff.added_binaries.end(); ++it)
	{
	  cout << "  " << (*it)->name << ", ";
	  string soname;
	  get_soname_of_elf_file((*it)->path, soname);
	  if (!soname.empty())
	    cout << "SONAME: " << soname;
	  else
	    cout << "no SONAME";
	  cout << "\n";
	}
    }

  // Erase temporary directory tree we might have left behind.
  maybe_erase_temp_dirs(first_package, second_package, opts);

  status = notifier.status;

  return status;
}

/// Compare the ABI of two packages.
///
/// @param first_package the first package to consider.
///
/// @param second_package the second package to consider.
///
/// @param opts the options the current program has been called with.
///
/// @return the status of the comparison.
static abidiff_status
compare(package& first_package, package& second_package, options& opts)
{
  abi_diff diff;
  return compare(first_package, second_package, diff, opts);
}

/// Parse the command line of the current program.
///
/// @param argc the number of arguments in the @p argv parameter.
///
/// @param argv the array of arguemnts passed to the function.  The
/// first argument is the name of this program.
///
/// @param opts the resulting options.
///
/// @return true upon successful parsing.
static bool
parse_command_line(int argc, char* argv[], options& opts)
{
  if (argc < 2)
    return false;

  for (int i = 1; i < argc; ++i)
    {
      if (argv[i][0] != '-')
        {
          if (opts.package1.empty())
            {
              opts.package1 = abigail::tools_utils::make_path_absolute(argv[i]).get();
              opts.nonexistent_file = !file_exists(opts.package1);
            }
          else if (opts.package2.empty())
            {
              opts.package2 = abigail::tools_utils::make_path_absolute(argv[i]).get();
              opts.nonexistent_file = !file_exists(opts.package2);
            }
          else
	    {
	      opts.wrong_arg = argv[i];
	      return false;
	    }

          if (opts.nonexistent_file)
            {
              opts.wrong_option = argv[i];
              return true;
            }
        }
      else if (!strcmp(argv[i], "--debug-info-pkg1")
	       || !strcmp(argv[i], "--d1"))
        {
          int j = i + 1;
          if (j >= argc)
            {
	      opts.missing_operand = true;
	      opts.wrong_option = argv[i];
	      return true;
            }
          opts.debug_package1 =
	    abigail::tools_utils::make_path_absolute(argv[j]).get();
          ++i;
        }
      else if (!strcmp(argv[i], "--debug-info-pkg2")
	       || !strcmp(argv[i], "--d2"))
        {
          int j = i + 1;
          if (j >= argc)
            {
	      opts.missing_operand = true;
	      opts.wrong_option = argv[i];
	      return true;
            }
          opts.debug_package2 =
	    abigail::tools_utils::make_path_absolute(argv[j]).get();
          ++i;
        }
      else if (!strcmp(argv[i], "--devel-pkg1")
	       || !strcmp(argv[i], "--devel1"))
        {
          int j = i + 1;
          if (j >= argc)
            {
	      opts.missing_operand = true;
	      opts.wrong_option = argv[i];
	      return true;
            }
          opts.devel_package1 =
	    abigail::tools_utils::make_path_absolute(argv[j]).get();
          ++i;
        }
      else if (!strcmp(argv[i], "--devel-pkg2")
	       || !strcmp(argv[i], "--devel2"))
        {
          int j = i + 1;
          if (j >= argc)
            {
	      opts.missing_operand = true;
	      opts.wrong_option = argv[i];
	      return true;
            }
          opts.devel_package2 =
	    abigail::tools_utils::make_path_absolute(argv[j]).get();
          ++i;
        }
      else if (!strcmp(argv[i], "--drop-private-types"))
	opts.drop_private_types = true;
      else if (!strcmp(argv[i], "--no-default-suppression"))
	opts.no_default_suppression = true;
      else if (!strcmp(argv[i], "--keep-tmp-files"))
	opts.keep_tmp_files = true;
      else if (!strcmp(argv[i], "--dso-only"))
	opts.compare_dso_only = true;
      else if (!strcmp(argv[i], "--no-linkage-name"))
	opts.show_linkage_names = false;
      else if (!strcmp(argv[i], "--redundant"))
	opts.show_redundant_changes = true;
      else if (!strcmp(argv[i], "--harmless"))
	opts.show_harmless_changes = true;
      else if (!strcmp(argv[i], "--no-show-locs"))
	opts.show_locs = false;
      else if (!strcmp(argv[i], "--no-show-relative-offset-changes"))
	opts.show_relative_offset_changes = false;
      else if (!strcmp(argv[i], "--no-added-syms"))
	opts.show_added_syms = false;
      else if (!strcmp(argv[i], "--no-added-binaries"))
	opts.show_added_binaries = false;
      else if (!strcmp(argv[i], "--fail-no-dbg"))
	opts.fail_if_no_debug_info = true;
      else if (!strcmp(argv[i], "--verbose"))
	opts.verbose = true;
      else if (!strcmp(argv[i], "--no-abignore"))
	opts.abignore = false;
      else if (!strcmp(argv[i], "--no-parallel"))
	opts.parallel = false;
      else if (!strcmp(argv[i], "--show-identical-binaries"))
	opts.show_identical_binaries = true;
      else if (!strcmp(argv[i], "--suppressions")
	       || !strcmp(argv[i], "--suppr"))
	{
	  int j = i + 1;
	  if (j >= argc)
	    return false;
	  opts.suppression_paths.push_back(argv[j]);
	  ++i;
	}
      else if (!strcmp(argv[i], "--help")
	       || !strcmp(argv[i], "-h"))
        {
          opts.display_usage = true;
          return true;
        }
      else if (!strcmp(argv[i], "--version")
	       || !strcmp(argv[i], "-v"))
	{
	  opts.display_version = true;
	  return true;
	}
      else
	{
	  if (strlen(argv[i]) >= 2 && argv[i][0] == '-' && argv[i][1] == '-')
	    opts.wrong_option = argv[i];
	  return false;
	}
    }

  return true;
}

int
main(int argc, char* argv[])
{
  options opts(argv[0]);

  if (!parse_command_line(argc, argv, opts))
    {
      if (!opts.wrong_option.empty())
	emit_prefix("abipkgdiff", cerr)
	  << "unrecognized option: " << opts.wrong_option
	  << "\ntry the --help option for more information\n";
      else
	emit_prefix("abipkgdiff", cerr)
	  << "unrecognized argument: " << opts.wrong_arg
	  << "\ntry the --help option for more information\n";
      return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
	      | abigail::tools_utils::ABIDIFF_ERROR);
    }

  if (opts.missing_operand)
    {
      emit_prefix("abipkgdiff", cerr)
	<< "missing operand\n"
        "try the --help option for more information\n";
      return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
	      | abigail::tools_utils::ABIDIFF_ERROR);
    }

  if (opts.nonexistent_file)
    {
      string input_file;
      base_name(opts.wrong_option, input_file);
      emit_prefix("abipkgdiff", cerr)
	<< "The input file " << input_file << " doesn't exist\n"
	"try the --help option for more information\n";
      return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
	      | abigail::tools_utils::ABIDIFF_ERROR);
    }

  if (opts.display_usage)
    {
      display_usage(argv[0], cout);
      return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
	      | abigail::tools_utils::ABIDIFF_ERROR);
    }

  if (opts.display_version)
    {
      string major, minor, revision;
      abigail::abigail_get_library_version(major, minor, revision);
      cout << major << "." << minor << "." << revision << "\n";
      return 0;
    }

    if (!opts.no_default_suppression && opts.suppression_paths.empty())
    {
      // Load the default system and user suppressions.
      string default_system_suppr_file =
	get_default_system_suppression_file_path();
      if (file_exists(default_system_suppr_file))
	opts.suppression_paths.push_back(default_system_suppr_file);

      string default_user_suppr_file =
	get_default_user_suppression_file_path();
      if (file_exists(default_user_suppr_file))
	opts.suppression_paths.push_back(default_user_suppr_file);
    }

  if (!maybe_check_suppression_files(opts))
    return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
	    | abigail::tools_utils::ABIDIFF_ERROR);

  if (opts.package1.empty() || opts.package2.empty())
    {
      emit_prefix("abipkgdiff", cerr)
	<< "Please enter two packages to compare" << "\n";
      return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
	      | abigail::tools_utils::ABIDIFF_ERROR);
    }

  package_sptr first_package(new package(opts.package1, "package1"));

  package_sptr second_package(new package(opts.package2, "package2"));

  if (!opts.debug_package1.empty())
    first_package->debug_info_package
      (package_sptr(new package(opts.debug_package1,
				"debug_package1",
				/*pkg_kind=*/package::KIND_DEBUG_INFO)));

  if (!opts.debug_package2.empty())
    second_package->debug_info_package
      (package_sptr(new package(opts.debug_package2,
				"debug_package2",
				/*pkg_kind=*/package::KIND_DEBUG_INFO)));

  if (!opts.devel_package1.empty())
    first_package->devel_package
      (package_sptr(new package(opts.devel_package1,
				"devel_package1",
				/*pkg_kind=*/package::KIND_DEVEL)));
    ;

  if (!opts.devel_package2.empty())
    second_package->devel_package
      (package_sptr(new package(opts.devel_package2,
				"devel_package2",
				/*pkg_kind=*/package::KIND_DEVEL)));

  string package_name;
  switch (first_package->type())
    {
    case abigail::tools_utils::FILE_TYPE_RPM:
      if (second_package->type() != abigail::tools_utils::FILE_TYPE_RPM)
	{
	  base_name(opts.package2, package_name);
	  emit_prefix("abipkgdiff", cerr)
	    << package_name << " should be an RPM file\n";
	  return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
		  | abigail::tools_utils::ABIDIFF_ERROR);
	}
      break;

    case abigail::tools_utils::FILE_TYPE_DEB:
      if (second_package->type() != abigail::tools_utils::FILE_TYPE_DEB)
	{
	  base_name(opts.package2, package_name);
	  emit_prefix("abipkgdiff", cerr)
	    << package_name << " should be a DEB file\n";
	  return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
		  | abigail::tools_utils::ABIDIFF_ERROR);
	}
      break;

    case abigail::tools_utils::FILE_TYPE_DIR:
      if (second_package->type() != abigail::tools_utils::FILE_TYPE_DIR)
	{
	  base_name(opts.package2, package_name);
	  emit_prefix("abipkgdiff", cerr)
	    << package_name << " should be a directory\n";
	  return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
		  | abigail::tools_utils::ABIDIFF_ERROR);
	}
      break;

    case abigail::tools_utils::FILE_TYPE_TAR:
      if (second_package->type() != abigail::tools_utils::FILE_TYPE_TAR)
	{
	  base_name(opts.package2, package_name);
	  emit_prefix("abipkgdiff", cerr)
	    << package_name << " should be a GNU tar archive\n";
	  return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
		  | abigail::tools_utils::ABIDIFF_ERROR);
	}
      break;

    default:
      base_name(opts.package1, package_name);
      emit_prefix("abipkgdiff", cerr)
	<< package_name << " should be a valid package file \n";
      return (abigail::tools_utils::ABIDIFF_USAGE_ERROR
	      | abigail::tools_utils::ABIDIFF_ERROR);
    }

  return compare(*first_package, *second_package, opts);
}