/*============================================================================
  CMake - Cross Platform Makefile Generator
  Copyright 2000-2009 Kitware, Inc., Insight Software Consortium

  Distributed under the OSI-approved BSD License (the "License");
  see accompanying file Copyright.txt for details.

  This software is distributed WITHOUT ANY WARRANTY; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the License for more information.
============================================================================*/
#include "cmCPackDebGenerator.h"

#include "cmSystemTools.h"
#include "cmMakefile.h"
#include "cmGeneratedFileStream.h"
#include "cmCPackLog.h"
#include "cmArchiveWrite.h"

#include <cmsys/SystemTools.hxx>
#include <cmsys/Glob.hxx>

#include <limits.h> // USHRT_MAX
#include <sys/stat.h>

// NOTE:
// A debian package .deb is simply an 'ar' archive. The only subtle difference
// is that debian uses the BSD ar style archive whereas most Linux distro have
// a GNU ar.
// See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=161593 for more info
// Therefore we provide our own implementation of a BSD-ar:
static int ar_append(const char*archive,const std::vector<std::string>& files);

//----------------------------------------------------------------------
cmCPackDebGenerator::cmCPackDebGenerator()
{
}

//----------------------------------------------------------------------
cmCPackDebGenerator::~cmCPackDebGenerator()
{
}

//----------------------------------------------------------------------
int cmCPackDebGenerator::InitializeInternal()
{
  this->SetOptionIfNotSet("CPACK_PACKAGING_INSTALL_PREFIX", "/usr");
  if (cmSystemTools::IsOff(this->GetOption("CPACK_SET_DESTDIR")))
    {
    this->SetOption("CPACK_SET_DESTDIR", "I_ON");
    }
  return this->Superclass::InitializeInternal();
}

//----------------------------------------------------------------------
int cmCPackDebGenerator::PackageOnePack(std::string initialTopLevel,
                                        std::string packageName)
  {
  int retval = 1;
  // Begin the archive for this pack
  std::string localToplevel(initialTopLevel);
  std::string packageFileName(
      cmSystemTools::GetParentDirectory(toplevel)
  );
  std::string outputFileName(
      std::string(this->GetOption("CPACK_PACKAGE_FILE_NAME"))
  +"-"+packageName + this->GetOutputExtension()
  );

  localToplevel += "/"+ packageName;
  /* replace the TEMP DIRECTORY with the component one */
  this->SetOption("CPACK_TEMPORARY_DIRECTORY",localToplevel.c_str());
  packageFileName += "/"+ outputFileName;
  /* replace proposed CPACK_OUTPUT_FILE_NAME */
  this->SetOption("CPACK_OUTPUT_FILE_NAME",outputFileName.c_str());
  /* replace the TEMPORARY package file name */
  this->SetOption("CPACK_TEMPORARY_PACKAGE_FILE_NAME",
      packageFileName.c_str());
  // Tell CPackDeb.cmake the name of the component GROUP.
  this->SetOption("CPACK_DEB_PACKAGE_COMPONENT",packageName.c_str());
  // Tell CPackDeb.cmake the path where the component is.
  std::string component_path = "/";
  component_path += packageName;
  this->SetOption("CPACK_DEB_PACKAGE_COMPONENT_PART_PATH",
                  component_path.c_str());
  if (!this->ReadListFile("CPackDeb.cmake"))
    {
    cmCPackLogger(cmCPackLog::LOG_ERROR,
        "Error while execution CPackDeb.cmake" << std::endl);
    retval = 0;
    return retval;
    }

  cmsys::Glob gl;
  std::string findExpr(this->GetOption("GEN_WDIR"));
  findExpr += "/*";
  gl.RecurseOn();
  gl.SetRecurseListDirs(true);
  if ( !gl.FindFiles(findExpr) )
    {
    cmCPackLogger(cmCPackLog::LOG_ERROR,
        "Cannot find any files in the installed directory" << std::endl);
    return 0;
    }
  packageFiles = gl.GetFiles();

  int res = createDeb();
  if (res != 1)
    {
    retval = 0;
    }
  // add the generated package to package file names list
  packageFileNames.push_back(packageFileName);
  return retval;
}

//----------------------------------------------------------------------
int cmCPackDebGenerator::PackageComponents(bool ignoreGroup)
{
  int retval = 1;
  /* Reset package file name list it will be populated during the
   * component packaging run*/
  packageFileNames.clear();
  std::string initialTopLevel(this->GetOption("CPACK_TEMPORARY_DIRECTORY"));

  // The default behavior is to have one package by component group
  // unless CPACK_COMPONENTS_IGNORE_GROUP is specified.
  if (!ignoreGroup)
    {
    std::map<std::string, cmCPackComponentGroup>::iterator compGIt;
    for (compGIt=this->ComponentGroups.begin();
        compGIt!=this->ComponentGroups.end(); ++compGIt)
      {
      cmCPackLogger(cmCPackLog::LOG_VERBOSE, "Packaging component group: "
          << compGIt->first
          << std::endl);
      // Begin the archive for this group
      retval &= PackageOnePack(initialTopLevel,compGIt->first);
      }
    // Handle Orphan components (components not belonging to any groups)
    std::map<std::string, cmCPackComponent>::iterator compIt;
    for (compIt=this->Components.begin();
        compIt!=this->Components.end(); ++compIt )
      {
      // Does the component belong to a group?
      if (compIt->second.Group==NULL)
        {
        cmCPackLogger(cmCPackLog::LOG_VERBOSE,
            "Component <"
            << compIt->second.Name
            << "> does not belong to any group, package it separately."
            << std::endl);
        // Begin the archive for this orphan component
        retval &= PackageOnePack(initialTopLevel,compIt->first);
        }
      }
    }
  // CPACK_COMPONENTS_IGNORE_GROUPS is set
  // We build 1 package per component
  else
    {
    std::map<std::string, cmCPackComponent>::iterator compIt;
    for (compIt=this->Components.begin();
         compIt!=this->Components.end(); ++compIt )
      {
      retval &= PackageOnePack(initialTopLevel,compIt->first);
      }
    }
  return retval;
}

//----------------------------------------------------------------------
int cmCPackDebGenerator::PackageComponentsAllInOne()
{
  int retval = 1;
  std::string compInstDirName;
  /* Reset package file name list it will be populated during the
   * component packaging run*/
  packageFileNames.clear();
  std::string initialTopLevel(this->GetOption("CPACK_TEMPORARY_DIRECTORY"));

  compInstDirName = "ALL_COMPONENTS_IN_ONE";

  cmCPackLogger(cmCPackLog::LOG_VERBOSE,
                "Packaging all groups in one package..."
                "(CPACK_COMPONENTS_ALL_[GROUPS_]IN_ONE_PACKAGE is set)"
      << std::endl);

  // The ALL GROUPS in ONE package case
  std::string localToplevel(initialTopLevel);
  std::string packageFileName(
      cmSystemTools::GetParentDirectory(toplevel)
                             );
  std::string outputFileName(
            std::string(this->GetOption("CPACK_PACKAGE_FILE_NAME"))
            + this->GetOutputExtension()
                            );
  // all GROUP in one vs all COMPONENT in one
  localToplevel += "/"+compInstDirName;

  /* replace the TEMP DIRECTORY with the component one */
  this->SetOption("CPACK_TEMPORARY_DIRECTORY",localToplevel.c_str());
  packageFileName += "/"+ outputFileName;
  /* replace proposed CPACK_OUTPUT_FILE_NAME */
  this->SetOption("CPACK_OUTPUT_FILE_NAME",outputFileName.c_str());
  /* replace the TEMPORARY package file name */
  this->SetOption("CPACK_TEMPORARY_PACKAGE_FILE_NAME",
      packageFileName.c_str());
  // Tell CPackDeb.cmake the path where the component is.
  std::string component_path = "/";
  component_path += compInstDirName;
  this->SetOption("CPACK_DEB_PACKAGE_COMPONENT_PART_PATH",
                  component_path.c_str());
  if (!this->ReadListFile("CPackDeb.cmake"))
    {
    cmCPackLogger(cmCPackLog::LOG_ERROR,
        "Error while execution CPackDeb.cmake" << std::endl);
    retval = 0;
    return retval;
    }

  cmsys::Glob gl;
  std::string findExpr(this->GetOption("GEN_WDIR"));
  findExpr += "/*";
  gl.RecurseOn();
  gl.SetRecurseListDirs(true);
  if ( !gl.FindFiles(findExpr) )
    {
    cmCPackLogger(cmCPackLog::LOG_ERROR,
    "Cannot find any files in the installed directory" << std::endl);
    return 0;
    }
  packageFiles = gl.GetFiles();

  int res = createDeb();
  if (res != 1)
    {
    retval = 0;
    }
  // add the generated package to package file names list
  packageFileNames.push_back(packageFileName);
  return retval;
}

//----------------------------------------------------------------------
int cmCPackDebGenerator::PackageFiles()
{
  int retval = -1;

  /* Are we in the component packaging case */
  if (WantsComponentInstallation()) {
    // CASE 1 : COMPONENT ALL-IN-ONE package
    // If ALL GROUPS or ALL COMPONENTS in ONE package has been requested
    // then the package file is unique and should be open here.
    if (componentPackageMethod == ONE_PACKAGE)
      {
      return PackageComponentsAllInOne();
      }
    // CASE 2 : COMPONENT CLASSICAL package(s) (i.e. not all-in-one)
    // There will be 1 package for each component group
    // however one may require to ignore component group and
    // in this case you'll get 1 package for each component.
    else
      {
      return PackageComponents(componentPackageMethod ==
                               ONE_PACKAGE_PER_COMPONENT);
      }
  }
  // CASE 3 : NON COMPONENT package.
  else
    {
    if (!this->ReadListFile("CPackDeb.cmake"))
      {
      cmCPackLogger(cmCPackLog::LOG_ERROR,
                    "Error while execution CPackDeb.cmake" << std::endl);
      retval = 0;
      }
    else
      {
      packageFiles = files;
      return createDeb();
      }
    }
  return retval;
}

int cmCPackDebGenerator::createDeb()
{
  // debian-binary file
  std::string dbfilename;
    dbfilename += this->GetOption("GEN_WDIR");
  dbfilename += "/debian-binary";
    { // the scope is needed for cmGeneratedFileStream
    cmGeneratedFileStream out(dbfilename.c_str());
    out << "2.0";
    out << std::endl; // required for valid debian package
    }

  // control file
  std::string ctlfilename;
    ctlfilename = this->GetOption("GEN_WDIR");
  ctlfilename += "/control";

  // debian policy enforce lower case for package name
  // mandatory entries:
  std::string debian_pkg_name = cmsys::SystemTools::LowerCase(
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_NAME") );
  const char* debian_pkg_version =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_VERSION");
  const char* debian_pkg_section =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_SECTION");
  const char* debian_pkg_priority =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_PRIORITY");
  const char* debian_pkg_arch =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_ARCHITECTURE");
  const char* maintainer =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_MAINTAINER");
  const char* desc =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_DESCRIPTION");

  // optional entries
  const char* debian_pkg_dep =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_DEPENDS");
  const char* debian_pkg_rec =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_RECOMMENDS");
  const char* debian_pkg_sug =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_SUGGESTS");
  const char* debian_pkg_url =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_HOMEPAGE");
  const char* debian_pkg_predep =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_PREDEPENDS");
  const char* debian_pkg_enhances =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_ENHANCES");
  const char* debian_pkg_breaks =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_BREAKS");
  const char* debian_pkg_conflicts =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_CONFLICTS");
  const char* debian_pkg_provides =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_PROVIDES");
  const char* debian_pkg_replaces =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_REPLACES");
  const char* debian_pkg_source =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_SOURCE");


    { // the scope is needed for cmGeneratedFileStream
    cmGeneratedFileStream out(ctlfilename.c_str());
    out << "Package: " << debian_pkg_name << "\n";
    out << "Version: " << debian_pkg_version << "\n";
    out << "Section: " << debian_pkg_section << "\n";
    out << "Priority: " << debian_pkg_priority << "\n";
    out << "Architecture: " << debian_pkg_arch << "\n";
    if(debian_pkg_source && *debian_pkg_source)
      {
      out << "Source: " << debian_pkg_source << "\n";
      }
    if(debian_pkg_dep && *debian_pkg_dep)
      {
      out << "Depends: " << debian_pkg_dep << "\n";
      }
    if(debian_pkg_rec && *debian_pkg_rec)
      {
      out << "Recommends: " << debian_pkg_rec << "\n";
      }
    if(debian_pkg_sug && *debian_pkg_sug)
      {
      out << "Suggests: " << debian_pkg_sug << "\n";
      }
    if(debian_pkg_url && *debian_pkg_url)
      {
      out << "Homepage: " << debian_pkg_url << "\n";
      }
    if (debian_pkg_predep && *debian_pkg_predep)
      {
      out << "Pre-Depends: " << debian_pkg_predep << "\n";
      }
    if (debian_pkg_enhances && *debian_pkg_enhances)
      {
      out << "Enhances: " << debian_pkg_enhances << "\n";
      }
    if (debian_pkg_breaks && *debian_pkg_breaks)
      {
      out << "Breaks: " << debian_pkg_breaks << "\n";
      }
    if (debian_pkg_conflicts && *debian_pkg_conflicts)
      {
      out << "Conflicts: " << debian_pkg_conflicts << "\n";
      }
    if (debian_pkg_provides && *debian_pkg_provides)
      {
      out << "Provides: " << debian_pkg_provides << "\n";
      }
    if (debian_pkg_replaces && *debian_pkg_replaces)
      {
      out << "Replaces: " << debian_pkg_replaces << "\n";
      }
    unsigned long totalSize = 0;
    {
      std::string dirName = this->GetOption("CPACK_TEMPORARY_DIRECTORY");
      dirName += '/';
      for (std::vector<std::string>::const_iterator fileIt =
           packageFiles.begin();
           fileIt != packageFiles.end(); ++ fileIt )
        {
        totalSize += cmSystemTools::FileLength(*fileIt);
        }
    }
    out << "Installed-Size: " << (totalSize + 1023) / 1024 << "\n";
    out << "Maintainer: " << maintainer << "\n";
    out << "Description: " << desc << "\n";
    out << std::endl;
    }

  const std::string strGenWDIR(this->GetOption("GEN_WDIR"));

  cmArchiveWrite::Compress tar_compression_type = cmArchiveWrite::CompressGZip;
  const char* debian_compression_type =
      this->GetOption("GEN_CPACK_DEBIAN_COMPRESSION_TYPE");
  if(!debian_compression_type)
    {
    debian_compression_type = "gzip";
    }

  std::string compression_suffix;
  if(!strcmp(debian_compression_type, "lzma")) {
      compression_suffix = ".lzma";
      tar_compression_type = cmArchiveWrite::CompressLZMA;
  } else if(!strcmp(debian_compression_type, "xz")) {
      compression_suffix = ".xz";
      tar_compression_type = cmArchiveWrite::CompressXZ;
  } else if(!strcmp(debian_compression_type, "bzip2")) {
      compression_suffix = ".bz2";
      tar_compression_type = cmArchiveWrite::CompressBZip2;
  } else if(!strcmp(debian_compression_type, "gzip")) {
      compression_suffix = ".gz";
      tar_compression_type = cmArchiveWrite::CompressGZip;
  } else if(!strcmp(debian_compression_type, "none")) {
      compression_suffix = "";
      tar_compression_type = cmArchiveWrite::CompressNone;
  } else {
      cmCPackLogger(cmCPackLog::LOG_ERROR,
                    "Error unrecognized compression type: "
                    << debian_compression_type << std::endl);
  }


  std::string filename_data_tar = strGenWDIR
      + "/data.tar" + compression_suffix;

  // atomic file generation for data.tar
  {
    cmGeneratedFileStream fileStream_data_tar;
    fileStream_data_tar.Open(filename_data_tar.c_str(), false, true);
    if(!fileStream_data_tar)
      {
      cmCPackLogger(cmCPackLog::LOG_ERROR,
          "Error opening the file \"" << filename_data_tar << "\" for writing"
          << std::endl);
      return 0;
      }
    cmArchiveWrite data_tar(fileStream_data_tar, tar_compression_type, "paxr");

    // uid/gid should be the one of the root user, and this root user has
    // always uid/gid equal to 0.
    data_tar.SetUIDAndGID(0u, 0u);
    data_tar.SetUNAMEAndGNAME("root", "root");

    // now add all directories which have to be compressed
    // collect all top level install dirs for that
    // e.g. /opt/bin/foo, /usr/bin/bar and /usr/bin/baz would
    // give /usr and /opt
    size_t topLevelLength = strGenWDIR.length();
    cmCPackLogger(cmCPackLog::LOG_DEBUG, "WDIR: \""
            << strGenWDIR
            << "\", length = " << topLevelLength
            << std::endl);
    std::set<std::string> orderedFiles;

    // we have to reconstruct the parent folders as well

    for (std::vector<std::string>::const_iterator fileIt =
         packageFiles.begin();
         fileIt != packageFiles.end(); ++ fileIt )
      {
      std::string currentPath = *fileIt;
      while(currentPath != strGenWDIR)
        {
        // the last one IS strGenWDIR, but we do not want this one:
        // XXX/application/usr/bin/myprogram with GEN_WDIR=XXX/application
        // should not add XXX/application
        orderedFiles.insert(currentPath);
        currentPath = cmSystemTools::CollapseCombinedPath(currentPath, "..");
        }
      }


    for (std::set<std::string>::const_iterator fileIt =
         orderedFiles.begin();
         fileIt != orderedFiles.end(); ++ fileIt )
      {
      cmCPackLogger(cmCPackLog::LOG_DEBUG, "FILEIT: \"" << *fileIt << "\""
                    << std::endl);
      std::string::size_type slashPos = fileIt->find('/', topLevelLength+1);
      std::string relativeDir = fileIt->substr(topLevelLength,
                                               slashPos - topLevelLength);
      cmCPackLogger(cmCPackLog::LOG_DEBUG, "RELATIVEDIR: \"" << relativeDir
                    << "\"" << std::endl);

      // do not recurse because the loop will do it
      if(!data_tar.Add(*fileIt, topLevelLength, ".", false))
        {
        cmCPackLogger(cmCPackLog::LOG_ERROR,
                      "Problem adding file to tar:" << std::endl
                      << "#top level directory: "
                      << strGenWDIR << std::endl
                      << "#file: " << *fileIt << std::endl
                      << "#error:" << data_tar.GetError() << std::endl);
        return 0;
        }
      }
  } // scope for file generation


  std::string md5filename = strGenWDIR + "/md5sums";
  {
    // the scope is needed for cmGeneratedFileStream
    cmGeneratedFileStream out(md5filename.c_str());

    std::string topLevelWithTrailingSlash =
        this->GetOption("CPACK_TEMPORARY_DIRECTORY");
    topLevelWithTrailingSlash += '/';
    for (std::vector<std::string>::const_iterator fileIt =
           packageFiles.begin();
         fileIt != packageFiles.end(); ++ fileIt )
      {
      // hash only regular files
      if(   cmSystemTools::FileIsDirectory(*fileIt)
         || cmSystemTools::FileIsSymlink(*fileIt))
        {
        continue;
        }

      char md5sum[33];
      if(!cmSystemTools::ComputeFileMD5(*fileIt, md5sum))
        {
        cmCPackLogger(cmCPackLog::LOG_ERROR, "Problem computing the md5 of "
                      << *fileIt << std::endl);
        }

      md5sum[32] = 0;

      std::string output(md5sum);
      output += "  " + *fileIt + "\n";
      // debian md5sums entries are like this:
      // 014f3604694729f3bf19263bac599765  usr/bin/ccmake
      // thus strip the full path (with the trailing slash)
      cmSystemTools::ReplaceString(output,
                                   topLevelWithTrailingSlash.c_str(), "");
      out << output;
      }
    // each line contains a eol.
    // Do not end the md5sum file with yet another (invalid)
  }


  std::string filename_control_tar = strGenWDIR + "/control.tar.gz";
  // atomic file generation for control.tar
  {
    cmGeneratedFileStream fileStream_control_tar;
    fileStream_control_tar.Open(filename_control_tar.c_str(), false, true);
    if(!fileStream_control_tar)
      {
      cmCPackLogger(cmCPackLog::LOG_ERROR,
          "Error opening the file \"" << filename_control_tar
          << "\" for writing" << std::endl);
      return 0;
      }
    cmArchiveWrite control_tar(fileStream_control_tar,
                               cmArchiveWrite::CompressGZip,
                               "paxr");

    // sets permissions and uid/gid for the files
    control_tar.SetUIDAndGID(0u, 0u);
    control_tar.SetUNAMEAndGNAME("root", "root");

    /* permissions are set according to
    https://www.debian.org/doc/debian-policy/ch-files.html#s-permissions-owners
    and
    https://lintian.debian.org/tags/control-file-has-bad-permissions.html
    */
    const mode_t permission644 = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
    const mode_t permissionExecute = S_IXUSR | S_IXGRP | S_IXOTH;
    const mode_t permission755 = permission644 | permissionExecute;

    // for md5sum and control (that we have generated here), we use 644
    // (RW-R--R--)
    // so that deb lintian doesn't warn about it
    control_tar.SetPermissions(permission644);

    // adds control and md5sums
    if(   !control_tar.Add(md5filename, strGenWDIR.length(), ".")
       || !control_tar.Add(strGenWDIR + "/control", strGenWDIR.length(), "."))
      {
        cmCPackLogger(cmCPackLog::LOG_ERROR,
            "Error adding file to tar:" << std::endl
            << "#top level directory: "
               << strGenWDIR << std::endl
            << "#file: \"control\" or \"md5sums\"" << std::endl
            << "#error:" << control_tar.GetError() << std::endl);
        return 0;
      }

    // for the other files, we use
    // -either the original permission on the files
    // -either a permission strictly defined by the Debian policies
    const char* controlExtra =
      this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_CONTROL_EXTRA");
    if( controlExtra )
      {
      // permissions are now controlled by the original file permissions

      const bool permissionStrictPolicy =
        this->IsSet("GEN_CPACK_DEBIAN_PACKAGE_CONTROL_STRICT_PERMISSION");

      static const char* strictFiles[] = {
        "config", "postinst", "postrm", "preinst", "prerm"
        };
      std::set<std::string> setStrictFiles(
        strictFiles,
        strictFiles + sizeof(strictFiles)/sizeof(strictFiles[0]));

      // default
      control_tar.ClearPermissions();

      std::vector<std::string> controlExtraList;
      cmSystemTools::ExpandListArgument(controlExtra, controlExtraList);
      for(std::vector<std::string>::iterator i = controlExtraList.begin();
          i != controlExtraList.end(); ++i)
        {
        std::string filenamename =
          cmsys::SystemTools::GetFilenameName(*i);
        std::string localcopy = strGenWDIR + "/" + filenamename;

        if(permissionStrictPolicy)
          {
          control_tar.SetPermissions(setStrictFiles.count(filenamename) ?
            permission755 : permission644);
          }

        // if we can copy the file, it means it does exist, let's add it:
        if( cmsys::SystemTools::CopyFileIfDifferent(*i, localcopy) )
          {
          control_tar.Add(localcopy, strGenWDIR.length(), ".");
          }
        }
      }
  }


  // ar -r your-package-name.deb debian-binary control.tar.* data.tar.*
  // since debian packages require BSD ar (most Linux distros and even
  // FreeBSD and NetBSD ship GNU ar) we use a copy of OpenBSD ar here.
  std::vector<std::string> arFiles;
  std::string topLevelString = strGenWDIR + "/";
  arFiles.push_back(topLevelString + "debian-binary");
  arFiles.push_back(topLevelString + "control.tar.gz");
  arFiles.push_back(topLevelString + "data.tar" + compression_suffix);
  std::string outputFileName = this->GetOption("CPACK_TOPLEVEL_DIRECTORY");
  outputFileName += "/";
  outputFileName += this->GetOption("CPACK_OUTPUT_FILE_NAME");
  int res = ar_append(outputFileName.c_str(), arFiles);
  if ( res!=0 )
    {
    std::string tmpFile = this->GetOption("CPACK_TEMPORARY_PACKAGE_FILE_NAME");
    tmpFile += "/Deb.log";
    cmGeneratedFileStream ofs(tmpFile.c_str());
    ofs << "# Problem creating archive using: " << res << std::endl;
    return 0;
    }
  return 1;
}

bool cmCPackDebGenerator::SupportsComponentInstallation() const
  {
  if (IsOn("CPACK_DEB_COMPONENT_INSTALL"))
    {
      return true;
    }
  else
    {
      return false;
    }
  }

std::string cmCPackDebGenerator::GetComponentInstallDirNameSuffix(
    const std::string& componentName)
  {
  if (componentPackageMethod == ONE_PACKAGE_PER_COMPONENT) {
    return componentName;
  }

  if (componentPackageMethod == ONE_PACKAGE) {
    return std::string("ALL_COMPONENTS_IN_ONE");
  }
  // We have to find the name of the COMPONENT GROUP
  // the current COMPONENT belongs to.
  std::string groupVar = "CPACK_COMPONENT_" +
        cmSystemTools::UpperCase(componentName) + "_GROUP";
    if (NULL != GetOption(groupVar))
      {
      return std::string(GetOption(groupVar));
      }
    else
      {
      return componentName;
      }
  }


// The following code is taken from OpenBSD ar:
// http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ar/
// It has been slightly modified:
// -return error codes instead exit() in functions
// -use the stdio file I/O functions instead the file descriptor based ones
// -merged into one cxx file
// -no additional options supported
// The coding style hasn't been modified.

/*-
 * Copyright (c) 1990, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Hugh Smith at The University of Guelph.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define ARMAG           "!<arch>\n"        /* ar "magic number" */
#define SARMAG          8                  /* strlen(ARMAG); */

#define AR_EFMT1        "#1/"              /* extended format #1 */
#define ARFMAG          "`\n"

/* Header format strings. */
#define HDR1            "%s%-13d%-12ld%-6u%-6u%-8o%-10lld%2s"
#define HDR2             "%-16.16s%-12ld%-6u%-6u%-8o%-10lld%2s"

struct ar_hdr {
  char ar_name[16];                        /* name */
  char ar_date[12];                        /* modification time */
  char ar_uid[6];                          /* user id */
  char ar_gid[6];                          /* group id */
  char ar_mode[8];                         /* octal file permissions */
  char ar_size[10];                        /* size in bytes */
  char ar_fmag[2];                         /* consistency check */
};

/* Set up file copy. */
#define SETCF(from, fromname, to, toname, pad) { \
        cf.rFile = from; \
        cf.rname = fromname; \
        cf.wFile = to; \
        cf.wname = toname; \
        cf.flags = pad; \
}

/* File copy structure. */
typedef struct {
        FILE* rFile;                       /* read file descriptor */
        const char *rname;                 /* read name */
        FILE* wFile;                       /* write file descriptor */
        const char *wname;                 /* write name */
#define NOPAD        0x00                  /* don't pad */
#define WPAD        0x02                   /* pad on writes */
        unsigned int flags;                       /* pad flags */
} CF;

/* misc.c */

static const char * ar_rname(const char *path)
{
  const char *ind = strrchr(path, '/');
  return (ind ) ? ind + 1 : path;
}

/* archive.c */

typedef struct ar_hdr HDR;
static char ar_hb[sizeof(HDR) + 1];        /* real header */

static size_t ar_already_written;

/* copy_ar --
 *      Copy size bytes from one file to another - taking care to handle the
 *      extra byte (for odd size files) when reading archives and writing an
 *      extra byte if necessary when adding files to archive.  The length of
 *      the object is the long name plus the object itself; the variable
 *      already_written gets set if a long name was written.
 *
 *      The padding is really unnecessary, and is almost certainly a remnant
 *      of early archive formats where the header included binary data which
 *      a PDP-11 required to start on an even byte boundary.  (Or, perhaps,
 *      because 16-bit word addressed copies were faster?)  Anyhow, it should
 *      have been ripped out long ago.
 */
static int copy_ar(CF *cfp, off_t size)
{
  static char pad = '\n';
  off_t sz = size;
  size_t nr, nw;
  char buf[8*1024];

  if (sz == 0)
    return 0;

  FILE* from = cfp->rFile;
  FILE* to = cfp->wFile;
  while (sz &&
        (nr = fread(buf, 1, sz < static_cast<off_t>(sizeof(buf))
                    ? static_cast<size_t>(sz) : sizeof(buf), from ))
               > 0) {
    sz -= nr;
    for (size_t off = 0; off < nr; nr -= off, off += nw)
      if ((nw = fwrite(buf + off, 1, nr, to)) < nr)
        return -1;
    }
  if (sz)
    return -2;

  if (cfp->flags & WPAD && (size + ar_already_written) & 1
      && fwrite(&pad, 1, 1, to) != 1)
    return -4;

  return 0;
}

/* put_arobj --  Write an archive member to a file. */
static int put_arobj(CF *cfp, struct stat *sb)
{
  int result = 0;
  struct ar_hdr *hdr;

 /* If passed an sb structure, reading a file from disk.  Get stat(2)
  * information, build a name and construct a header.  (Files are named
  * by their last component in the archive.) */
  const char* name = ar_rname(cfp->rname);
  (void)stat(cfp->rname, sb);

 /* If not truncating names and the name is too long or contains
  * a space, use extended format 1.   */
  size_t lname = strlen(name);
  uid_t uid = sb->st_uid;
  gid_t gid = sb->st_gid;
  if (uid > USHRT_MAX) {
    uid = USHRT_MAX;
    }
  if (gid > USHRT_MAX) {
    gid = USHRT_MAX;
    }
  if (lname > sizeof(hdr->ar_name) || strchr(name, ' '))
    (void)sprintf(ar_hb, HDR1, AR_EFMT1, (int)lname,
                  (long int)sb->st_mtime, (unsigned)uid, (unsigned)gid,
                  (unsigned)sb->st_mode, (long long)sb->st_size + lname,
                  ARFMAG);
    else {
      lname = 0;
      (void)sprintf(ar_hb, HDR2, name,
                    (long int)sb->st_mtime, (unsigned)uid, (unsigned)gid,
                    (unsigned)sb->st_mode, (long long)sb->st_size,
                    ARFMAG);
      }
    off_t size = sb->st_size;

  if (fwrite(ar_hb, 1, sizeof(HDR), cfp->wFile) != sizeof(HDR))
    return -1;

  if (lname) {
    if (fwrite(name, 1, lname, cfp->wFile) != lname)
      return -2;
    ar_already_written = lname;
    }
  result = copy_ar(cfp, size);
  ar_already_written = 0;
  return result;
}

/* append.c */

/* append --
 *      Append files to the archive - modifies original archive or creates
 *      a new archive if named archive does not exist.
 */
static int ar_append(const char* archive,const std::vector<std::string>& files)
{
  int eval = 0;
  FILE* aFile = cmSystemTools::Fopen(archive, "wb+");
  if (aFile!=NULL) {
    fwrite(ARMAG, SARMAG, 1, aFile);
    if (fseek(aFile, 0, SEEK_END) != -1) {
      CF cf;
      struct stat sb;
      /* Read from disk, write to an archive; pad on write. */
      SETCF(NULL, 0, aFile, archive, WPAD);
      for(std::vector<std::string>::const_iterator fileIt = files.begin();
          fileIt!=files.end(); ++fileIt) {
        const char* filename = fileIt->c_str();
        FILE* file = cmSystemTools::Fopen(filename, "rb");
        if (file == NULL) {
          eval = -1;
          continue;
          }
        cf.rFile = file;
        cf.rname = filename;
        int result = put_arobj(&cf, &sb);
        (void)fclose(file);
        if (result!=0) {
          eval = -2;
          break;
          }
        }
      }
      else {
        eval = -3;
      }
    fclose(aFile);
    }
  else {
    eval = -4;
    }
  return eval;
}