Merge remote-tracking branch 'donkult/debian/sid' into debian/sid

[apt.git] / cmdline / apt-get.cc

// -*- mode: cpp; mode: fold -*-
// Description                                                          /*{{{*/
// $Id: apt-get.cc,v 1.156 2004/08/28 01:05:16 mdz Exp $
/* ######################################################################
   
   apt-get - Cover for dpkg
   
   This is an allout cover for dpkg implementing a safer front end. It is
   based largely on libapt-pkg.

   The syntax is different, 
      apt-get [opt] command [things]
   Where command is:
      update - Resyncronize the package files from their sources
      upgrade - Smart-Download the newest versions of all packages
      dselect-upgrade - Follows dselect's changes to the Status: field
                       and installes new and removes old packages
      dist-upgrade - Powerfull upgrader designed to handle the issues with
                    a new distribution.
      install - Download and install a given package (by name, not by .deb)
      check - Update the package cache and check for broken packages
      clean - Erase the .debs downloaded to /var/cache/apt/archives and
              the partial dir too

   ##################################################################### */
                                                                        /*}}}*/
// Include Files                                                        /*{{{*/
#include <config.h>

#include <apt-pkg/aptconfiguration.h>
#include <apt-pkg/error.h>
#include <apt-pkg/cmndline.h>
#include <apt-pkg/init.h>
#include <apt-pkg/depcache.h>
#include <apt-pkg/sourcelist.h>
#include <apt-pkg/algorithms.h>
#include <apt-pkg/acquire-item.h>
#include <apt-pkg/strutl.h>
#include <apt-pkg/fileutl.h>
#include <apt-pkg/clean.h>
#include <apt-pkg/srcrecords.h>
#include <apt-pkg/version.h>
#include <apt-pkg/cachefile.h>
#include <apt-pkg/cacheset.h>
#include <apt-pkg/sptr.h>
#include <apt-pkg/md5.h>
#include <apt-pkg/versionmatch.h>
#include <apt-pkg/progress.h>
#include <apt-pkg/pkgsystem.h>
#include <apt-pkg/pkgrecords.h>
#include <apt-pkg/indexfile.h>

#include <apt-private/private-download.h>
#include <apt-private/private-install.h>
#include <apt-private/private-upgrade.h>
#include <apt-private/private-output.h>
#include <apt-private/private-cacheset.h>
#include <apt-private/private-update.h>
#include <apt-private/private-cmndline.h>
#include <apt-private/private-moo.h>

#include <apt-private/acqprogress.h>

#include <set>
#include <fstream>
#include <sstream>

#include <locale.h>
#include <langinfo.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/statvfs.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <regex.h>
#include <sys/wait.h>

#include <apt-private/private-output.h>
#include <apt-private/private-main.h>

#include <apti18n.h>
                                                                        /*}}}*/

using namespace std;

// TryToInstallBuildDep - Try to install a single package               /*{{{*/
// ---------------------------------------------------------------------
/* This used to be inlined in DoInstall, but with the advent of regex package
   name matching it was split out.. */
bool TryToInstallBuildDep(pkgCache::PkgIterator Pkg,pkgCacheFile &Cache,
                  pkgProblemResolver &Fix,bool Remove,bool BrokenFix,
                  bool AllowFail = true)
{
   if (Cache[Pkg].CandidateVer == 0 && Pkg->ProvidesList != 0)
   {
      CacheSetHelperAPTGet helper(c1out);
      helper.showErrors(false);
      pkgCache::VerIterator Ver = helper.canNotFindNewestVer(Cache, Pkg);
      if (Ver.end() == false)
         Pkg = Ver.ParentPkg();
      else if (helper.showVirtualPackageErrors(Cache) == false)
         return AllowFail;
   }

   if (_config->FindB("Debug::BuildDeps",false) == true)
   {
      if (Remove == true)
         cout << "  Trying to remove " << Pkg << endl;
      else
         cout << "  Trying to install " << Pkg << endl;
   }

   if (Remove == true)
   {
      TryToRemove RemoveAction(Cache, &Fix);
      RemoveAction(Pkg.VersionList());
   } else if (Cache[Pkg].CandidateVer != 0) {
      TryToInstall InstallAction(Cache, &Fix, BrokenFix);
      InstallAction(Cache[Pkg].CandidateVerIter(Cache));
      InstallAction.doAutoInstall();
   } else
      return AllowFail;

   return true;
}
                                                                        /*}}}*/
// FindSrc - Find a source record                                       /*{{{*/
// ---------------------------------------------------------------------
/* */
pkgSrcRecords::Parser *FindSrc(const char *Name,pkgRecords &Recs,
                               pkgSrcRecords &SrcRecs,string &Src,
                               pkgDepCache &Cache)
{
   string VerTag;
   string DefRel = _config->Find("APT::Default-Release");
   string TmpSrc = Name;

   // extract the version/release from the pkgname
   const size_t found = TmpSrc.find_last_of("/=");
   if (found != string::npos) {
      if (TmpSrc[found] == '/')
         DefRel = TmpSrc.substr(found+1);
      else
         VerTag = TmpSrc.substr(found+1);
      TmpSrc = TmpSrc.substr(0,found);
   }

   /* Lookup the version of the package we would install if we were to
      install a version and determine the source package name, then look
      in the archive for a source package of the same name. */
   bool MatchSrcOnly = _config->FindB("APT::Get::Only-Source");
   const pkgCache::PkgIterator Pkg = Cache.FindPkg(TmpSrc);
   if (MatchSrcOnly == false && Pkg.end() == false) 
   {
      if(VerTag.empty() == false || DefRel.empty() == false) 
      {
         bool fuzzy = false;
         // we have a default release, try to locate the pkg. we do it like
         // this because GetCandidateVer() will not "downgrade", that means
         // "apt-get source -t stable apt" won't work on a unstable system
         for (pkgCache::VerIterator Ver = Pkg.VersionList();; ++Ver)
         {
            // try first only exact matches, later fuzzy matches
            if (Ver.end() == true)
            {
               if (fuzzy == true)
                  break;
               fuzzy = true;
               Ver = Pkg.VersionList();
               // exit right away from the Pkg.VersionList() loop if we
               // don't have any versions
               if (Ver.end() == true)
                  break;
            }
            // We match against a concrete version (or a part of this version)
            if (VerTag.empty() == false &&
                (fuzzy == true || Cache.VS().CmpVersion(VerTag, Ver.VerStr()) != 0) && // exact match
                (fuzzy == false || strncmp(VerTag.c_str(), Ver.VerStr(), VerTag.size()) != 0)) // fuzzy match
               continue;

            for (pkgCache::VerFileIterator VF = Ver.FileList();
                 VF.end() == false; ++VF)
            {
               /* If this is the status file, and the current version is not the
                  version in the status file (ie it is not installed, or somesuch)
                  then it is not a candidate for installation, ever. This weeds
                  out bogus entries that may be due to config-file states, or
                  other. */
               if ((VF.File()->Flags & pkgCache::Flag::NotSource) ==
                   pkgCache::Flag::NotSource && Pkg.CurrentVer() != Ver)
                  continue;

               // or we match against a release
               if(VerTag.empty() == false ||
                  (VF.File().Archive() != 0 && VF.File().Archive() == DefRel) ||
                  (VF.File().Codename() != 0 && VF.File().Codename() == DefRel)) 
               {
                  pkgRecords::Parser &Parse = Recs.Lookup(VF);
                  Src = Parse.SourcePkg();
                  // no SourcePkg name, so it is the "binary" name
                  if (Src.empty() == true)
                     Src = TmpSrc;
                  // the Version we have is possibly fuzzy or includes binUploads,
                  // so we use the Version of the SourcePkg (empty if same as package)
                  VerTag = Parse.SourceVer();
                  if (VerTag.empty() == true)
                     VerTag = Ver.VerStr();
                  break;
               }
            }
            if (Src.empty() == false)
               break;
         }
         if (Src.empty() == true) 
         {
            // Sources files have no codename information
            if (VerTag.empty() == true && DefRel.empty() == false) 
            {
               _error->Error(_("Ignore unavailable target release '%s' of package '%s'"), DefRel.c_str(), TmpSrc.c_str());
               return 0;
            }
         }
      }
      if (Src.empty() == true)
      {
         // if we don't have found a fitting package yet so we will
         // choose a good candidate and proceed with that.
         // Maybe we will find a source later on with the right VerTag
         pkgCache::VerIterator Ver = Cache.GetCandidateVer(Pkg);
         if (Ver.end() == false) 
         {
            pkgRecords::Parser &Parse = Recs.Lookup(Ver.FileList());
            Src = Parse.SourcePkg();
            if (VerTag.empty() == true)
               VerTag = Parse.SourceVer();
         }
      }
   }

   if (Src.empty() == true)
      Src = TmpSrc;
   else 
   {
      /* if we have a source pkg name, make sure to only search
         for srcpkg names, otherwise apt gets confused if there
         is a binary package "pkg1" and a source package "pkg1"
         with the same name but that comes from different packages */
      MatchSrcOnly = true;
      if (Src != TmpSrc) 
      {
         ioprintf(c1out, _("Picking '%s' as source package instead of '%s'\n"), Src.c_str(), TmpSrc.c_str());
      }
   }

   // The best hit
   pkgSrcRecords::Parser *Last = 0;
   unsigned long Offset = 0;
   string Version;

   /* Iterate over all of the hits, which includes the resulting
      binary packages in the search */
   pkgSrcRecords::Parser *Parse;
   while (true) 
   {
      SrcRecs.Restart();
      while ((Parse = SrcRecs.Find(Src.c_str(), MatchSrcOnly)) != 0) 
      {
         const string Ver = Parse->Version();

         // Ignore all versions which doesn't fit
         if (VerTag.empty() == false &&
             Cache.VS().CmpVersion(VerTag, Ver) != 0) // exact match
            continue;

         // Newer version or an exact match? Save the hit
         if (Last == 0 || Cache.VS().CmpVersion(Version,Ver) < 0) {
            Last = Parse;
            Offset = Parse->Offset();
            Version = Ver;
         }

         // was the version check above an exact match? If so, we don't need to look further
         if (VerTag.empty() == false && VerTag.size() == Ver.size())
            break;
      }
      if (Last != 0 || VerTag.empty() == true)
         break;
      //if (VerTag.empty() == false && Last == 0)
      _error->Error(_("Ignore unavailable version '%s' of package '%s'"), VerTag.c_str(), TmpSrc.c_str());
      return 0;
   }

   if (Last == 0 || Last->Jump(Offset) == false)
      return 0;

   return Last;
}
                                                                        /*}}}*/
/* mark packages as automatically/manually installed.                   {{{*/
bool DoMarkAuto(CommandLine &CmdL)
{
   bool Action = true;
   int AutoMarkChanged = 0;
   OpTextProgress progress;
   CacheFile Cache;
   if (Cache.Open() == false)
      return false;

   if (strcasecmp(CmdL.FileList[0],"markauto") == 0)
      Action = true;
   else if (strcasecmp(CmdL.FileList[0],"unmarkauto") == 0)
      Action = false;

   for (const char **I = CmdL.FileList + 1; *I != 0; I++)
   {
      const char *S = *I;
      // Locate the package
      pkgCache::PkgIterator Pkg = Cache->FindPkg(S);
      if (Pkg.end() == true) {
         return _error->Error(_("Couldn't find package %s"),S);
      }
      else
      {
         if (!Action)
            ioprintf(c1out,_("%s set to manually installed.\n"), Pkg.Name());
         else
            ioprintf(c1out,_("%s set to automatically installed.\n"),
                      Pkg.Name());

         Cache->MarkAuto(Pkg,Action);
         AutoMarkChanged++;
      }
   }

   _error->Notice(_("This command is deprecated. Please use 'apt-mark auto' and 'apt-mark manual' instead."));

   if (AutoMarkChanged && ! _config->FindB("APT::Get::Simulate",false))
      return Cache->writeStateFile(NULL);
   return false;
}
                                                                        /*}}}*/
// DoDistUpgrade - Automatic smart upgrader                             /*{{{*/
// ---------------------------------------------------------------------
/* Intelligent upgrader that will install and remove packages at will */
bool DoDistUpgrade(CommandLine &CmdL)
{
   CacheFile Cache;
   if (Cache.OpenForInstall() == false || Cache.CheckDeps() == false)
      return false;

   c0out << _("Calculating upgrade... ") << flush;
   if (pkgDistUpgrade(*Cache) == false)
   {
      c0out << _("Failed") << endl;
      ShowBroken(c1out,Cache,false);
      return false;
   }
   
   // parse additional cmdline pkg manipulation switches
   if(!DoCacheManipulationFromCommandLine(CmdL, Cache))
      return false;

   c0out << _("Done") << endl;
   
   return InstallPackages(Cache,true);
}
                                                                        /*}}}*/
// DoDSelectUpgrade - Do an upgrade by following dselects selections    /*{{{*/
// ---------------------------------------------------------------------
/* Follows dselect's selections */
bool DoDSelectUpgrade(CommandLine &CmdL)
{
   CacheFile Cache;
   if (Cache.OpenForInstall() == false || Cache.CheckDeps() == false)
      return false;
   
   pkgDepCache::ActionGroup group(Cache);

   // Install everything with the install flag set
   pkgCache::PkgIterator I = Cache->PkgBegin();
   for (;I.end() != true; ++I)
   {
      /* Install the package only if it is a new install, the autoupgrader
         will deal with the rest */
      if (I->SelectedState == pkgCache::State::Install)
         Cache->MarkInstall(I,false);
   }

   /* Now install their deps too, if we do this above then order of
      the status file is significant for | groups */
   for (I = Cache->PkgBegin();I.end() != true; ++I)
   {
      /* Install the package only if it is a new install, the autoupgrader
         will deal with the rest */
      if (I->SelectedState == pkgCache::State::Install)
         Cache->MarkInstall(I,true);
   }
   
   // Apply erasures now, they override everything else.
   for (I = Cache->PkgBegin();I.end() != true; ++I)
   {
      // Remove packages 
      if (I->SelectedState == pkgCache::State::DeInstall ||
          I->SelectedState == pkgCache::State::Purge)
         Cache->MarkDelete(I,I->SelectedState == pkgCache::State::Purge);
   }

   /* Resolve any problems that dselect created, allupgrade cannot handle
      such things. We do so quite agressively too.. */
   if (Cache->BrokenCount() != 0)
   {      
      pkgProblemResolver Fix(Cache);

      // Hold back held packages.
      if (_config->FindB("APT::Ignore-Hold",false) == false)
      {
         for (pkgCache::PkgIterator I = Cache->PkgBegin(); I.end() == false; ++I)
         {
            if (I->SelectedState == pkgCache::State::Hold)
            {
               Fix.Protect(I);
               Cache->MarkKeep(I);
            }
         }
      }
   
      if (Fix.Resolve() == false)
      {
         ShowBroken(c1out,Cache,false);
         return _error->Error(_("Internal error, problem resolver broke stuff"));
      }
   }

   // Now upgrade everything
   if (pkgAllUpgrade(Cache) == false)
   {
      ShowBroken(c1out,Cache,false);
      return _error->Error(_("Internal error, problem resolver broke stuff"));
   }
   
   return InstallPackages(Cache,false);
}
                                                                        /*}}}*/
// DoClean - Remove download archives                                   /*{{{*/
// ---------------------------------------------------------------------
/* */
bool DoClean(CommandLine &CmdL)
{
   std::string const archivedir = _config->FindDir("Dir::Cache::archives");
   std::string const pkgcache = _config->FindFile("Dir::cache::pkgcache");
   std::string const srcpkgcache = _config->FindFile("Dir::cache::srcpkgcache");

   if (_config->FindB("APT::Get::Simulate") == true)
   {
      cout << "Del " << archivedir << "* " << archivedir << "partial/*"<< endl
           << "Del " << pkgcache << " " << srcpkgcache << endl;
      return true;
   }
   
   // Lock the archive directory
   FileFd Lock;
   if (_config->FindB("Debug::NoLocking",false) == false)
   {
      int lock_fd = GetLock(archivedir + "lock");
      if (lock_fd < 0)
         return _error->Error(_("Unable to lock the download directory"));
      Lock.Fd(lock_fd);
   }
   
   pkgAcquire Fetcher;
   Fetcher.Clean(archivedir);
   Fetcher.Clean(archivedir + "partial/");

   pkgCacheFile::RemoveCaches();

   return true;
}
                                                                        /*}}}*/
// DoAutoClean - Smartly remove downloaded archives                     /*{{{*/
// ---------------------------------------------------------------------
/* This is similar to clean but it only purges things that cannot be 
   downloaded, that is old versions of cached packages. */
class LogCleaner : public pkgArchiveCleaner
{
   protected:
   virtual void Erase(const char *File,string Pkg,string Ver,struct stat &St) 
   {
      c1out << "Del " << Pkg << " " << Ver << " [" << SizeToStr(St.st_size) << "B]" << endl;
      
      if (_config->FindB("APT::Get::Simulate") == false)
         unlink(File);      
   };
};

bool DoAutoClean(CommandLine &CmdL)
{
   // Lock the archive directory
   FileFd Lock;
   if (_config->FindB("Debug::NoLocking",false) == false)
   {
      int lock_fd = GetLock(_config->FindDir("Dir::Cache::Archives") + "lock");
      if (lock_fd < 0)
         return _error->Error(_("Unable to lock the download directory"));
      Lock.Fd(lock_fd);
   }
   
   CacheFile Cache;
   if (Cache.Open() == false)
      return false;
   
   LogCleaner Cleaner;
   
   return Cleaner.Go(_config->FindDir("Dir::Cache::archives"),*Cache) &&
      Cleaner.Go(_config->FindDir("Dir::Cache::archives") + "partial/",*Cache);
}
                                                                        /*}}}*/
// DoDownload - download a binary                                       /*{{{*/
// ---------------------------------------------------------------------
bool DoDownload(CommandLine &CmdL)
{
   CacheFile Cache;
   if (Cache.ReadOnlyOpen() == false)
      return false;

   APT::CacheSetHelper helper(c0out);
   APT::VersionList verset = APT::VersionList::FromCommandLine(Cache,
                CmdL.FileList + 1, APT::VersionList::CANDIDATE, helper);

   if (verset.empty() == true)
      return false;

   AcqTextStatus Stat(ScreenWidth, _config->FindI("quiet", 0));
   pkgAcquire Fetcher;
   if (Fetcher.Setup(&Stat) == false)
      return false;

   pkgRecords Recs(Cache);
   pkgSourceList *SrcList = Cache.GetSourceList();

   // reuse the usual acquire methods for deb files, but don't drop them into
   // the usual directories - keep everything in the current directory
   std::vector<std::string> storefile(verset.size());
   std::string const cwd = SafeGetCWD();
   _config->Set("Dir::Cache::Archives", cwd);
   int i = 0;
   for (APT::VersionList::const_iterator Ver = verset.begin();
         Ver != verset.end(); ++Ver, ++i)
   {
      pkgAcquire::Item *I = new pkgAcqArchive(&Fetcher, SrcList, &Recs, *Ver, storefile[i]);
      std::string const filename = cwd + flNotDir(storefile[i]);
      storefile[i].assign(filename);
      I->DestFile.assign(filename);
   }

   // Just print out the uris and exit if the --print-uris flag was used
   if (_config->FindB("APT::Get::Print-URIs") == true)
   {
      pkgAcquire::UriIterator I = Fetcher.UriBegin();
      for (; I != Fetcher.UriEnd(); ++I)
         cout << '\'' << I->URI << "' " << flNotDir(I->Owner->DestFile) << ' ' <<
               I->Owner->FileSize << ' ' << I->Owner->HashSum() << endl;
      return true;
   }

   if (_error->PendingError() == true || CheckAuth(Fetcher, false) == false)
      return false;

   bool Failed = false;
   if (AcquireRun(Fetcher, 0, &Failed, NULL) == false)
      return false;

   // copy files in local sources to the current directory
   for (pkgAcquire::ItemIterator I = Fetcher.ItemsBegin(); I != Fetcher.ItemsEnd(); ++I)
      if ((*I)->Local == true && (*I)->Status == pkgAcquire::Item::StatDone)
      {
         std::string const filename = cwd + flNotDir((*I)->DestFile);
         std::ifstream src((*I)->DestFile.c_str(), std::ios::binary);
         std::ofstream dst(filename.c_str(), std::ios::binary);
         dst << src.rdbuf();
      }

   return Failed == false;
}
                                                                        /*}}}*/
// DoCheck - Perform the check operation                                /*{{{*/
// ---------------------------------------------------------------------
/* Opening automatically checks the system, this command is mostly used
   for debugging */
bool DoCheck(CommandLine &CmdL)
{
   CacheFile Cache;
   Cache.Open();
   Cache.CheckDeps();
   
   return true;
}
                                                                        /*}}}*/
// DoSource - Fetch a source archive                                    /*{{{*/
// ---------------------------------------------------------------------
/* Fetch souce packages */
struct DscFile
{
   string Package;
   string Version;
   string Dsc;
};

bool DoSource(CommandLine &CmdL)
{
   CacheFile Cache;
   if (Cache.Open(false) == false)
      return false;

   if (CmdL.FileSize() <= 1)
      return _error->Error(_("Must specify at least one package to fetch source for"));
   
   // Read the source list
   if (Cache.BuildSourceList() == false)
      return false;
   pkgSourceList *List = Cache.GetSourceList();
   
   // Create the text record parsers
   pkgRecords Recs(Cache);
   pkgSrcRecords SrcRecs(*List);
   if (_error->PendingError() == true)
      return false;

   // Create the download object
   AcqTextStatus Stat(ScreenWidth,_config->FindI("quiet",0));   
   pkgAcquire Fetcher;
   Fetcher.SetLog(&Stat);

   DscFile *Dsc = new DscFile[CmdL.FileSize()];
   
   // insert all downloaded uris into this set to avoid downloading them
   // twice
   set<string> queued;

   // Diff only mode only fetches .diff files
   bool const diffOnly = _config->FindB("APT::Get::Diff-Only", false);
   // Tar only mode only fetches .tar files
   bool const tarOnly = _config->FindB("APT::Get::Tar-Only", false);
   // Dsc only mode only fetches .dsc files
   bool const dscOnly = _config->FindB("APT::Get::Dsc-Only", false);

   // Load the requestd sources into the fetcher
   unsigned J = 0;
   for (const char **I = CmdL.FileList + 1; *I != 0; I++, J++)
   {
      string Src;
      pkgSrcRecords::Parser *Last = FindSrc(*I,Recs,SrcRecs,Src,*Cache);
      
      if (Last == 0) {
         delete[] Dsc;
         return _error->Error(_("Unable to find a source package for %s"),Src.c_str());
      }
      
      string srec = Last->AsStr();
      string::size_type pos = srec.find("\nVcs-");
      while (pos != string::npos)
      {
         pos += strlen("\nVcs-");
         string vcs = srec.substr(pos,srec.find(":",pos)-pos);
         if(vcs == "Browser") 
         {
            pos = srec.find("\nVcs-", pos);
            continue;
         }
         pos += vcs.length()+2;
         string::size_type epos = srec.find("\n", pos);
         string uri = srec.substr(pos,epos-pos).c_str();
         ioprintf(c1out, _("NOTICE: '%s' packaging is maintained in "
                           "the '%s' version control system at:\n"
                           "%s\n"),
                  Src.c_str(), vcs.c_str(), uri.c_str());
         if(vcs == "Bzr") 
            ioprintf(c1out,_("Please use:\n"
                             "bzr branch %s\n"
                             "to retrieve the latest (possibly unreleased) "
                             "updates to the package.\n"),
                     uri.c_str());
         break;
      }

      // Back track
      vector<pkgSrcRecords::File> Lst;
      if (Last->Files(Lst) == false) {
         delete[] Dsc;
         return false;
      }

      // Load them into the fetcher
      for (vector<pkgSrcRecords::File>::const_iterator I = Lst.begin();
           I != Lst.end(); ++I)
      {
         // Try to guess what sort of file it is we are getting.
         if (I->Type == "dsc")
         {
            Dsc[J].Package = Last->Package();
            Dsc[J].Version = Last->Version();
            Dsc[J].Dsc = flNotDir(I->Path);
         }

         // Handle the only options so that multiple can be used at once
         if (diffOnly == true || tarOnly == true || dscOnly == true)
         {
            if ((diffOnly == true && I->Type == "diff") ||
                (tarOnly == true && I->Type == "tar") ||
                (dscOnly == true && I->Type == "dsc"))
                ; // Fine, we want this file downloaded
            else
               continue;
         }

         // don't download the same uri twice (should this be moved to
         // the fetcher interface itself?)
         if(queued.find(Last->Index().ArchiveURI(I->Path)) != queued.end())
            continue;
         queued.insert(Last->Index().ArchiveURI(I->Path));

         // check if we have a file with that md5 sum already localy
         if(!I->MD5Hash.empty() && FileExists(flNotDir(I->Path)))  
         {
            FileFd Fd(flNotDir(I->Path), FileFd::ReadOnly);
            MD5Summation sum;
            sum.AddFD(Fd.Fd(), Fd.Size());
            Fd.Close();
            if((string)sum.Result() == I->MD5Hash) 
            {
               ioprintf(c1out,_("Skipping already downloaded file '%s'\n"),
                        flNotDir(I->Path).c_str());
               continue;
            }
         }

         new pkgAcqFile(&Fetcher,Last->Index().ArchiveURI(I->Path),
                        I->MD5Hash,I->Size,
                        Last->Index().SourceInfo(*Last,*I),Src);
      }
   }
   
   // Display statistics
   unsigned long long FetchBytes = Fetcher.FetchNeeded();
   unsigned long long FetchPBytes = Fetcher.PartialPresent();
   unsigned long long DebBytes = Fetcher.TotalNeeded();

   // Check for enough free space
   struct statvfs Buf;
   string OutputDir = ".";
   if (statvfs(OutputDir.c_str(),&Buf) != 0) {
      delete[] Dsc;
      if (errno == EOVERFLOW)
         return _error->WarningE("statvfs",_("Couldn't determine free space in %s"),
                                OutputDir.c_str());
      else
         return _error->Errno("statvfs",_("Couldn't determine free space in %s"),
                                OutputDir.c_str());
   } else if (unsigned(Buf.f_bfree) < (FetchBytes - FetchPBytes)/Buf.f_bsize)
     {
       struct statfs Stat;
       if (statfs(OutputDir.c_str(),&Stat) != 0
#if HAVE_STRUCT_STATFS_F_TYPE
           || unsigned(Stat.f_type) != RAMFS_MAGIC
#endif
           )  {
         delete[] Dsc;
          return _error->Error(_("You don't have enough free space in %s"),
              OutputDir.c_str());
       }
     }
   
   // Number of bytes
   if (DebBytes != FetchBytes)
      //TRANSLATOR: The required space between number and unit is already included
      // in the replacement strings, so %sB will be correctly translate in e.g. 1,5 MB
      ioprintf(c1out,_("Need to get %sB/%sB of source archives.\n"),
               SizeToStr(FetchBytes).c_str(),SizeToStr(DebBytes).c_str());
   else
      //TRANSLATOR: The required space between number and unit is already included
      // in the replacement string, so %sB will be correctly translate in e.g. 1,5 MB
      ioprintf(c1out,_("Need to get %sB of source archives.\n"),
               SizeToStr(DebBytes).c_str());
   
   if (_config->FindB("APT::Get::Simulate",false) == true)
   {
      for (unsigned I = 0; I != J; I++)
         ioprintf(cout,_("Fetch source %s\n"),Dsc[I].Package.c_str());
      delete[] Dsc;
      return true;
   }
   
   // Just print out the uris an exit if the --print-uris flag was used
   if (_config->FindB("APT::Get::Print-URIs") == true)
   {
      pkgAcquire::UriIterator I = Fetcher.UriBegin();
      for (; I != Fetcher.UriEnd(); ++I)
         cout << '\'' << I->URI << "' " << flNotDir(I->Owner->DestFile) << ' ' << 
               I->Owner->FileSize << ' ' << I->Owner->HashSum() << endl;
      delete[] Dsc;
      return true;
   }

   // Run it
   bool Failed = false;
   if (AcquireRun(Fetcher, 0, &Failed, NULL) == false || Failed == true)
   {
      delete[] Dsc;
      return _error->Error(_("Failed to fetch some archives."));
   }

   if (_config->FindB("APT::Get::Download-only",false) == true)
   {
      c1out << _("Download complete and in download only mode") << endl;
      delete[] Dsc;
      return true;
   }

   // Unpack the sources
   pid_t Process = ExecFork();
   
   if (Process == 0)
   {
      bool const fixBroken = _config->FindB("APT::Get::Fix-Broken", false);
      for (unsigned I = 0; I != J; ++I)
      {
         string Dir = Dsc[I].Package + '-' + Cache->VS().UpstreamVersion(Dsc[I].Version.c_str());
         
         // Diff only mode only fetches .diff files
         if (_config->FindB("APT::Get::Diff-Only",false) == true ||
             _config->FindB("APT::Get::Tar-Only",false) == true ||
             Dsc[I].Dsc.empty() == true)
            continue;

         // See if the package is already unpacked
         struct stat Stat;
         if (fixBroken == false && stat(Dir.c_str(),&Stat) == 0 &&
             S_ISDIR(Stat.st_mode) != 0)
         {
            ioprintf(c0out ,_("Skipping unpack of already unpacked source in %s\n"),
                              Dir.c_str());
         }
         else
         {
            // Call dpkg-source
            char S[500];
            snprintf(S,sizeof(S),"%s -x %s",
                     _config->Find("Dir::Bin::dpkg-source","dpkg-source").c_str(),
                     Dsc[I].Dsc.c_str());
            if (system(S) != 0)
            {
               fprintf(stderr,_("Unpack command '%s' failed.\n"),S);
               fprintf(stderr,_("Check if the 'dpkg-dev' package is installed.\n"));
               _exit(1);
            }       
         }
         
         // Try to compile it with dpkg-buildpackage
         if (_config->FindB("APT::Get::Compile",false) == true)
         {
            string buildopts = _config->Find("APT::Get::Host-Architecture");
            if (buildopts.empty() == false)
               buildopts = "-a" + buildopts + " ";
            buildopts.append(_config->Find("DPkg::Build-Options","-b -uc"));

            // Call dpkg-buildpackage
            char S[500];
            snprintf(S,sizeof(S),"cd %s && %s %s",
                     Dir.c_str(),
                     _config->Find("Dir::Bin::dpkg-buildpackage","dpkg-buildpackage").c_str(),
                     buildopts.c_str());
            
            if (system(S) != 0)
            {
               fprintf(stderr,_("Build command '%s' failed.\n"),S);
               _exit(1);
            }       
         }      
      }
      
      _exit(0);
   }
   delete[] Dsc;

   // Wait for the subprocess
   int Status = 0;
   while (waitpid(Process,&Status,0) != Process)
   {
      if (errno == EINTR)
         continue;
      return _error->Errno("waitpid","Couldn't wait for subprocess");
   }

   if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
      return _error->Error(_("Child process failed"));
   
   return true;
}
                                                                        /*}}}*/
// DoBuildDep - Install/removes packages to satisfy build dependencies  /*{{{*/
// ---------------------------------------------------------------------
/* This function will look at the build depends list of the given source 
   package and install the necessary packages to make it true, or fail. */
bool DoBuildDep(CommandLine &CmdL)
{
   CacheFile Cache;

   _config->Set("APT::Install-Recommends", false);
   
   if (Cache.Open(true) == false)
      return false;

   if (CmdL.FileSize() <= 1)
      return _error->Error(_("Must specify at least one package to check builddeps for"));
   
   // Read the source list
   if (Cache.BuildSourceList() == false)
      return false;
   pkgSourceList *List = Cache.GetSourceList();
   
   // Create the text record parsers
   pkgRecords Recs(Cache);
   pkgSrcRecords SrcRecs(*List);
   if (_error->PendingError() == true)
      return false;

   // Create the download object
   AcqTextStatus Stat(ScreenWidth,_config->FindI("quiet",0));   
   pkgAcquire Fetcher;
   if (Fetcher.Setup(&Stat) == false)
      return false;

   bool StripMultiArch;
   string hostArch = _config->Find("APT::Get::Host-Architecture");
   if (hostArch.empty() == false)
   {
      std::vector<std::string> archs = APT::Configuration::getArchitectures();
      if (std::find(archs.begin(), archs.end(), hostArch) == archs.end())
         return _error->Error(_("No architecture information available for %s. See apt.conf(5) APT::Architectures for setup"), hostArch.c_str());
      StripMultiArch = false;
   }
   else
      StripMultiArch = true;

   unsigned J = 0;
   for (const char **I = CmdL.FileList + 1; *I != 0; I++, J++)
   {
      string Src;
      pkgSrcRecords::Parser *Last = FindSrc(*I,Recs,SrcRecs,Src,*Cache);
      if (Last == 0)
         return _error->Error(_("Unable to find a source package for %s"),Src.c_str());
            
      // Process the build-dependencies
      vector<pkgSrcRecords::Parser::BuildDepRec> BuildDeps;
      // FIXME: Can't specify architecture to use for [wildcard] matching, so switch default arch temporary
      if (hostArch.empty() == false)
      {
         std::string nativeArch = _config->Find("APT::Architecture");
         _config->Set("APT::Architecture", hostArch);
         bool Success = Last->BuildDepends(BuildDeps, _config->FindB("APT::Get::Arch-Only", false), StripMultiArch);
         _config->Set("APT::Architecture", nativeArch);
         if (Success == false)
            return _error->Error(_("Unable to get build-dependency information for %s"),Src.c_str());
      }
      else if (Last->BuildDepends(BuildDeps, _config->FindB("APT::Get::Arch-Only", false), StripMultiArch) == false)
            return _error->Error(_("Unable to get build-dependency information for %s"),Src.c_str());
   
      // Also ensure that build-essential packages are present
      Configuration::Item const *Opts = _config->Tree("APT::Build-Essential");
      if (Opts) 
         Opts = Opts->Child;
      for (; Opts; Opts = Opts->Next)
      {
         if (Opts->Value.empty() == true)
            continue;

         pkgSrcRecords::Parser::BuildDepRec rec;
         rec.Package = Opts->Value;
         rec.Type = pkgSrcRecords::Parser::BuildDependIndep;
         rec.Op = 0;
         BuildDeps.push_back(rec);
      }

      if (BuildDeps.empty() == true)
      {
         ioprintf(c1out,_("%s has no build depends.\n"),Src.c_str());
         continue;
      }

      // Install the requested packages
      vector <pkgSrcRecords::Parser::BuildDepRec>::iterator D;
      pkgProblemResolver Fix(Cache);
      bool skipAlternatives = false; // skip remaining alternatives in an or group
      for (D = BuildDeps.begin(); D != BuildDeps.end(); ++D)
      {
         bool hasAlternatives = (((*D).Op & pkgCache::Dep::Or) == pkgCache::Dep::Or);

         if (skipAlternatives == true)
         {
            /*
             * if there are alternatives, we've already picked one, so skip
             * the rest
             *
             * TODO: this means that if there's a build-dep on A|B and B is
             * installed, we'll still try to install A; more importantly,
             * if A is currently broken, we cannot go back and try B. To fix 
             * this would require we do a Resolve cycle for each package we 
             * add to the install list. Ugh
             */
            if (!hasAlternatives)
               skipAlternatives = false; // end of or group
            continue;
         }

         if ((*D).Type == pkgSrcRecords::Parser::BuildConflict ||
             (*D).Type == pkgSrcRecords::Parser::BuildConflictIndep)
         {
            pkgCache::GrpIterator Grp = Cache->FindGrp((*D).Package);
            // Build-conflicts on unknown packages are silently ignored
            if (Grp.end() == true)
               continue;

            for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg))
            {
               pkgCache::VerIterator IV = (*Cache)[Pkg].InstVerIter(*Cache);
               /*
                * Remove if we have an installed version that satisfies the
                * version criteria
                */
               if (IV.end() == false &&
                   Cache->VS().CheckDep(IV.VerStr(),(*D).Op,(*D).Version.c_str()) == true)
                  TryToInstallBuildDep(Pkg,Cache,Fix,true,false);
            }
         }
         else // BuildDep || BuildDepIndep
         {
            if (_config->FindB("Debug::BuildDeps",false) == true)
                 cout << "Looking for " << (*D).Package << "...\n";

            pkgCache::PkgIterator Pkg;

            // Cross-Building?
            if (StripMultiArch == false && D->Type != pkgSrcRecords::Parser::BuildDependIndep)
            {
               size_t const colon = D->Package.find(":");
               if (colon != string::npos)
               {
                  if (strcmp(D->Package.c_str() + colon, ":any") == 0 || strcmp(D->Package.c_str() + colon, ":native") == 0)
                     Pkg = Cache->FindPkg(D->Package.substr(0,colon));
                  else
                     Pkg = Cache->FindPkg(D->Package);
               }
               else
                  Pkg = Cache->FindPkg(D->Package, hostArch);

               // a bad version either is invalid or doesn't satify dependency
               #define BADVER(Ver) (Ver.end() == true || \
                                    (D->Version.empty() == false && \
                                     Cache->VS().CheckDep(Ver.VerStr(),D->Op,D->Version.c_str()) == false))

               APT::VersionList verlist;
               if (Pkg.end() == false)
               {
                  pkgCache::VerIterator Ver = (*Cache)[Pkg].InstVerIter(*Cache);
                  if (BADVER(Ver) == false)
                     verlist.insert(Ver);
                  Ver = (*Cache)[Pkg].CandidateVerIter(*Cache);
                  if (BADVER(Ver) == false)
                     verlist.insert(Ver);
               }
               if (verlist.empty() == true)
               {
                  pkgCache::PkgIterator BuildPkg = Cache->FindPkg(D->Package, "native");
                  if (BuildPkg.end() == false && Pkg != BuildPkg)
                  {
                     pkgCache::VerIterator Ver = (*Cache)[BuildPkg].InstVerIter(*Cache);
                     if (BADVER(Ver) == false)
                        verlist.insert(Ver);
                     Ver = (*Cache)[BuildPkg].CandidateVerIter(*Cache);
                     if (BADVER(Ver) == false)
                        verlist.insert(Ver);
                  }
               }
               #undef BADVER

               string forbidden;
               // We need to decide if host or build arch, so find a version we can look at
               APT::VersionList::const_iterator Ver = verlist.begin();
               for (; Ver != verlist.end(); ++Ver)
               {
                  forbidden.clear();
                  if (Ver->MultiArch == pkgCache::Version::None || Ver->MultiArch == pkgCache::Version::All)
                  {
                     if (colon == string::npos)
                        Pkg = Ver.ParentPkg().Group().FindPkg(hostArch);
                     else if (strcmp(D->Package.c_str() + colon, ":any") == 0)
                        forbidden = "Multi-Arch: none";
                     else if (strcmp(D->Package.c_str() + colon, ":native") == 0)
                        Pkg = Ver.ParentPkg().Group().FindPkg("native");
                  }
                  else if (Ver->MultiArch == pkgCache::Version::Same)
                  {
                     if (colon == string::npos)
                        Pkg = Ver.ParentPkg().Group().FindPkg(hostArch);
                     else if (strcmp(D->Package.c_str() + colon, ":any") == 0)
                        forbidden = "Multi-Arch: same";
                     else if (strcmp(D->Package.c_str() + colon, ":native") == 0)
                        Pkg = Ver.ParentPkg().Group().FindPkg("native");
                  }
                  else if ((Ver->MultiArch & pkgCache::Version::Foreign) == pkgCache::Version::Foreign)
                  {
                     if (colon == string::npos)
                        Pkg = Ver.ParentPkg().Group().FindPkg("native");
                     else if (strcmp(D->Package.c_str() + colon, ":any") == 0 ||
                              strcmp(D->Package.c_str() + colon, ":native") == 0)
                        forbidden = "Multi-Arch: foreign";
                  }
                  else if ((Ver->MultiArch & pkgCache::Version::Allowed) == pkgCache::Version::Allowed)
                  {
                     if (colon == string::npos)
                        Pkg = Ver.ParentPkg().Group().FindPkg(hostArch);
                     else if (strcmp(D->Package.c_str() + colon, ":any") == 0)
                     {
                        // prefer any installed over preferred non-installed architectures
                        pkgCache::GrpIterator Grp = Ver.ParentPkg().Group();
                        // we don't check for version here as we are better of with upgrading than remove and install
                        for (Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg))
                           if (Pkg.CurrentVer().end() == false)
                              break;
                        if (Pkg.end() == true)
                           Pkg = Grp.FindPreferredPkg(true);
                     }
                     else if (strcmp(D->Package.c_str() + colon, ":native") == 0)
                        Pkg = Ver.ParentPkg().Group().FindPkg("native");
                  }

                  if (forbidden.empty() == false)
                  {
                     if (_config->FindB("Debug::BuildDeps",false) == true)
                        cout << D->Package.substr(colon, string::npos) << " is not allowed from " << forbidden << " package " << (*D).Package << " (" << Ver.VerStr() << ")" << endl;
                     continue;
                  }

                  //we found a good version
                  break;
               }
               if (Ver == verlist.end())
               {
                  if (_config->FindB("Debug::BuildDeps",false) == true)
                     cout << " No multiarch info as we have no satisfying installed nor candidate for " << D->Package << " on build or host arch" << endl;

                  if (forbidden.empty() == false)
                  {
                     if (hasAlternatives)
                        continue;
                     return _error->Error(_("%s dependency for %s can't be satisfied "
                                            "because %s is not allowed on '%s' packages"),
                                          Last->BuildDepType(D->Type), Src.c_str(),
                                          D->Package.c_str(), forbidden.c_str());
                  }
               }
            }
            else
               Pkg = Cache->FindPkg(D->Package);

            if (Pkg.end() == true || (Pkg->VersionList == 0 && Pkg->ProvidesList == 0))
            {
               if (_config->FindB("Debug::BuildDeps",false) == true)
                    cout << " (not found)" << (*D).Package << endl;

               if (hasAlternatives)
                  continue;

               return _error->Error(_("%s dependency for %s cannot be satisfied "
                                      "because the package %s cannot be found"),
                                    Last->BuildDepType((*D).Type),Src.c_str(),
                                    (*D).Package.c_str());
            }

            pkgCache::VerIterator IV = (*Cache)[Pkg].InstVerIter(*Cache);
            if (IV.end() == false)
            {
               if (_config->FindB("Debug::BuildDeps",false) == true)
                  cout << "  Is installed\n";

               if (D->Version.empty() == true ||
                   Cache->VS().CheckDep(IV.VerStr(),(*D).Op,(*D).Version.c_str()) == true)
               {
                  skipAlternatives = hasAlternatives;
                  continue;
               }

               if (_config->FindB("Debug::BuildDeps",false) == true)
                  cout << "    ...but the installed version doesn't meet the version requirement\n";

               if (((*D).Op & pkgCache::Dep::LessEq) == pkgCache::Dep::LessEq)
                  return _error->Error(_("Failed to satisfy %s dependency for %s: Installed package %s is too new"),
                                        Last->BuildDepType((*D).Type), Src.c_str(), Pkg.FullName(true).c_str());
            }

            // Only consider virtual packages if there is no versioned dependency
            if ((*D).Version.empty() == true)
            {
               /*
                * If this is a virtual package, we need to check the list of
                * packages that provide it and see if any of those are
                * installed
                */
               pkgCache::PrvIterator Prv = Pkg.ProvidesList();
               for (; Prv.end() != true; ++Prv)
               {
                  if (_config->FindB("Debug::BuildDeps",false) == true)
                     cout << "  Checking provider " << Prv.OwnerPkg().FullName() << endl;

                  if ((*Cache)[Prv.OwnerPkg()].InstVerIter(*Cache).end() == false)
                     break;
               }

               if (Prv.end() == false)
               {
                  if (_config->FindB("Debug::BuildDeps",false) == true)
                     cout << "  Is provided by installed package " << Prv.OwnerPkg().FullName() << endl;
                  skipAlternatives = hasAlternatives;
                  continue;
               }
            }
            else // versioned dependency
            {
               pkgCache::VerIterator CV = (*Cache)[Pkg].CandidateVerIter(*Cache);
               if (CV.end() == true ||
                   Cache->VS().CheckDep(CV.VerStr(),(*D).Op,(*D).Version.c_str()) == false)
               {
                  if (hasAlternatives)
                     continue;
                  else if (CV.end() == false)
                     return _error->Error(_("%s dependency for %s cannot be satisfied "
                                            "because candidate version of package %s "
                                            "can't satisfy version requirements"),
                                          Last->BuildDepType(D->Type), Src.c_str(),
                                          D->Package.c_str());
                  else
                     return _error->Error(_("%s dependency for %s cannot be satisfied "
                                            "because package %s has no candidate version"),
                                          Last->BuildDepType(D->Type), Src.c_str(),
                                          D->Package.c_str());
               }
            }

            if (TryToInstallBuildDep(Pkg,Cache,Fix,false,false,false) == true)
            {
               // We successfully installed something; skip remaining alternatives
               skipAlternatives = hasAlternatives;
               if(_config->FindB("APT::Get::Build-Dep-Automatic", false) == true)
                  Cache->MarkAuto(Pkg, true);
               continue;
            }
            else if (hasAlternatives)
            {
               if (_config->FindB("Debug::BuildDeps",false) == true)
                  cout << "  Unsatisfiable, trying alternatives\n";
               continue;
            }
            else
            {
               return _error->Error(_("Failed to satisfy %s dependency for %s: %s"),
                                    Last->BuildDepType((*D).Type),
                                    Src.c_str(),
                                    (*D).Package.c_str());
            }
         }             
      }

      if (Fix.Resolve(true) == false)
         _error->Discard();
      
      // Now we check the state of the packages,
      if (Cache->BrokenCount() != 0)
      {
         ShowBroken(cout, Cache, false);
         return _error->Error(_("Build-dependencies for %s could not be satisfied."),*I);
      }
   }
  
   if (InstallPackages(Cache, false, true) == false)
      return _error->Error(_("Failed to process build dependencies"));
   return true;
}
                                                                        /*}}}*/
// GetChangelogPath - return a path pointing to a changelog file or dir /*{{{*/
// ---------------------------------------------------------------------
/* This returns a "path" string for the changelog url construction.
 * Please note that its not complete, it either needs a "/changelog"
 * appended (for the packages.debian.org/changelogs site) or a
 * ".changelog" (for third party sites that store the changelog in the
 * pool/ next to the deb itself)
 * Example return: "pool/main/a/apt/apt_0.8.8ubuntu3" 
 */
string GetChangelogPath(CacheFile &Cache, 
                        pkgCache::PkgIterator Pkg,
                        pkgCache::VerIterator Ver)
{
   string path;

   pkgRecords Recs(Cache);
   pkgRecords::Parser &rec=Recs.Lookup(Ver.FileList());
   string srcpkg = rec.SourcePkg().empty() ? Pkg.Name() : rec.SourcePkg();
   string ver = Ver.VerStr();
   // if there is a source version it always wins
   if (rec.SourceVer() != "")
      ver = rec.SourceVer();
   path = flNotFile(rec.FileName());
   path += srcpkg + "_" + StripEpoch(ver);
   return path;
}
                                                                        /*}}}*/
// GuessThirdPartyChangelogUri - return url                             /*{{{*/
// ---------------------------------------------------------------------
/* Contruct a changelog file path for third party sites that do not use
 * packages.debian.org/changelogs
 * This simply uses the ArchiveURI() of the source pkg and looks for
 * a .changelog file there, Example for "mediabuntu":
 * apt-get changelog mplayer-doc:
 *  http://packages.medibuntu.org/pool/non-free/m/mplayer/mplayer_1.0~rc4~try1.dsfg1-1ubuntu1+medibuntu1.changelog
 */
bool GuessThirdPartyChangelogUri(CacheFile &Cache, 
                                 pkgCache::PkgIterator Pkg,
                                 pkgCache::VerIterator Ver,
                                 string &out_uri)
{
   // get the binary deb server path
   pkgCache::VerFileIterator Vf = Ver.FileList();
   if (Vf.end() == true)
      return false;
   pkgCache::PkgFileIterator F = Vf.File();
   pkgIndexFile *index;
   pkgSourceList *SrcList = Cache.GetSourceList();
   if(SrcList->FindIndex(F, index) == false)
      return false;

   // get archive uri for the binary deb
   string path_without_dot_changelog = GetChangelogPath(Cache, Pkg, Ver);
   out_uri = index->ArchiveURI(path_without_dot_changelog + ".changelog");

   // now strip away the filename and add srcpkg_srcver.changelog
   return true;
}
                                                                        /*}}}*/
// DownloadChangelog - Download the changelog                           /*{{{*/
// ---------------------------------------------------------------------
bool DownloadChangelog(CacheFile &CacheFile, pkgAcquire &Fetcher, 
                       pkgCache::VerIterator Ver, string targetfile)
/* Download a changelog file for the given package version to
 * targetfile. This will first try the server from Apt::Changelogs::Server
 * (http://packages.debian.org/changelogs by default) and if that gives
 * a 404 tries to get it from the archive directly (see 
 * GuessThirdPartyChangelogUri for details how)
 */
{
   string path;
   string descr;
   string server;
   string changelog_uri;

   // data structures we need
   pkgCache::PkgIterator Pkg = Ver.ParentPkg();

   // make the server root configurable
   server = _config->Find("Apt::Changelogs::Server",
                          "http://packages.debian.org/changelogs");
   path = GetChangelogPath(CacheFile, Pkg, Ver);
   strprintf(changelog_uri, "%s/%s/changelog", server.c_str(), path.c_str());
   if (_config->FindB("APT::Get::Print-URIs", false) == true)
   {
      std::cout << '\'' << changelog_uri << '\'' << std::endl;
      return true;
   }

   strprintf(descr, _("Changelog for %s (%s)"), Pkg.Name(), changelog_uri.c_str());
   // queue it
   new pkgAcqFile(&Fetcher, changelog_uri, "", 0, descr, Pkg.Name(), "ignored", targetfile);

   // try downloading it, if that fails, try third-party-changelogs location
   // FIXME: Fetcher.Run() is "Continue" even if I get a 404?!?
   Fetcher.Run();
   if (!FileExists(targetfile))
   {
      string third_party_uri;
      if (GuessThirdPartyChangelogUri(CacheFile, Pkg, Ver, third_party_uri))
      {
         strprintf(descr, _("Changelog for %s (%s)"), Pkg.Name(), third_party_uri.c_str());
         new pkgAcqFile(&Fetcher, third_party_uri, "", 0, descr, Pkg.Name(), "ignored", targetfile);
         Fetcher.Run();
      }
   }

   if (FileExists(targetfile))
      return true;

   // error
   return _error->Error("changelog download failed");
}
                                                                        /*}}}*/
// DisplayFileInPager - Display File with pager                         /*{{{*/
void DisplayFileInPager(string filename)
{
   pid_t Process = ExecFork();
   if (Process == 0)
   {
      const char *Args[3];
      Args[0] = "/usr/bin/sensible-pager";
      Args[1] = filename.c_str();
      Args[2] = 0;
      execvp(Args[0],(char **)Args);
      exit(100);
   }
         
   // Wait for the subprocess
   ExecWait(Process, "sensible-pager", false);
}
                                                                        /*}}}*/
// DoChangelog - Get changelog from the command line                    /*{{{*/
// ---------------------------------------------------------------------
bool DoChangelog(CommandLine &CmdL)
{
   CacheFile Cache;
   if (Cache.ReadOnlyOpen() == false)
      return false;
   
   APT::CacheSetHelper helper(c0out);
   APT::VersionList verset = APT::VersionList::FromCommandLine(Cache,
                CmdL.FileList + 1, APT::VersionList::CANDIDATE, helper);
   if (verset.empty() == true)
      return false;
   pkgAcquire Fetcher;

   if (_config->FindB("APT::Get::Print-URIs", false) == true)
   {
      bool Success = true;
      for (APT::VersionList::const_iterator Ver = verset.begin();
           Ver != verset.end(); ++Ver)
         Success &= DownloadChangelog(Cache, Fetcher, Ver, "");
      return Success;
   }

   AcqTextStatus Stat(ScreenWidth, _config->FindI("quiet",0));
   Fetcher.Setup(&Stat);

   bool const downOnly = _config->FindB("APT::Get::Download-Only", false);

   char tmpname[100];
   char* tmpdir = NULL;
   if (downOnly == false)
   {
      const char* const tmpDir = getenv("TMPDIR");
      if (tmpDir != NULL && *tmpDir != '\0')
         snprintf(tmpname, sizeof(tmpname), "%s/apt-changelog-XXXXXX", tmpDir);
      else
         strncpy(tmpname, "/tmp/apt-changelog-XXXXXX", sizeof(tmpname));
      tmpdir = mkdtemp(tmpname);
      if (tmpdir == NULL)
         return _error->Errno("mkdtemp", "mkdtemp failed");
   }

   for (APT::VersionList::const_iterator Ver = verset.begin(); 
        Ver != verset.end(); 
        ++Ver) 
   {
      string changelogfile;
      if (downOnly == false)
         changelogfile.append(tmpname).append("changelog");
      else
         changelogfile.append(Ver.ParentPkg().Name()).append(".changelog");
      if (DownloadChangelog(Cache, Fetcher, Ver, changelogfile) && downOnly == false)
      {
         DisplayFileInPager(changelogfile);
         // cleanup temp file
         unlink(changelogfile.c_str());
      }
   }
   // clenaup tmp dir
   if (tmpdir != NULL)
      rmdir(tmpdir);
   return true;
}
                                                                        /*}}}*/
// ShowHelp - Show a help screen                                        /*{{{*/
// ---------------------------------------------------------------------
/* */
bool ShowHelp(CommandLine &CmdL)
{
   ioprintf(cout,_("%s %s for %s compiled on %s %s\n"),PACKAGE,PACKAGE_VERSION,
            COMMON_ARCH,__DATE__,__TIME__);
            
   if (_config->FindB("version") == true)
   {
      cout << _("Supported modules:") << endl;
      
      for (unsigned I = 0; I != pkgVersioningSystem::GlobalListLen; I++)
      {
         pkgVersioningSystem *VS = pkgVersioningSystem::GlobalList[I];
         if (_system != 0 && _system->VS == VS)
            cout << '*';
         else
            cout << ' ';
         cout << "Ver: " << VS->Label << endl;
         
         /* Print out all the packaging systems that will work with 
            this VS */
         for (unsigned J = 0; J != pkgSystem::GlobalListLen; J++)
         {
            pkgSystem *Sys = pkgSystem::GlobalList[J];
            if (_system == Sys)
               cout << '*';
            else
               cout << ' ';
            if (Sys->VS->TestCompatibility(*VS) == true)
               cout << "Pkg:  " << Sys->Label << " (Priority " << Sys->Score(*_config) << ")" << endl;
         }
      }
      
      for (unsigned I = 0; I != pkgSourceList::Type::GlobalListLen; I++)
      {
         pkgSourceList::Type *Type = pkgSourceList::Type::GlobalList[I];
         cout << " S.L: '" << Type->Name << "' " << Type->Label << endl;
      }      
      
      for (unsigned I = 0; I != pkgIndexFile::Type::GlobalListLen; I++)
      {
         pkgIndexFile::Type *Type = pkgIndexFile::Type::GlobalList[I];
         cout << " Idx: " << Type->Label << endl;
      }      
      
      return true;
   }
   
   cout << 
    _("Usage: apt-get [options] command\n"
      "       apt-get [options] install|remove pkg1 [pkg2 ...]\n"
      "       apt-get [options] source pkg1 [pkg2 ...]\n"
      "\n"
      "apt-get is a simple command line interface for downloading and\n"
      "installing packages. The most frequently used commands are update\n"
      "and install.\n"   
      "\n"
      "Commands:\n"
      "   update - Retrieve new lists of packages\n"
      "   upgrade - Perform an upgrade\n"
      "   install - Install new packages (pkg is libc6 not libc6.deb)\n"
      "   remove - Remove packages\n"
      "   autoremove - Remove automatically all unused packages\n"
      "   purge - Remove packages and config files\n"
      "   source - Download source archives\n"
      "   build-dep - Configure build-dependencies for source packages\n"
      "   dist-upgrade - Distribution upgrade, see apt-get(8)\n"
      "   dselect-upgrade - Follow dselect selections\n"
      "   clean - Erase downloaded archive files\n"
      "   autoclean - Erase old downloaded archive files\n"
      "   check - Verify that there are no broken dependencies\n"
      "   changelog - Download and display the changelog for the given package\n"
      "   download - Download the binary package into the current directory\n"
      "\n"
      "Options:\n"
      "  -h  This help text.\n"
      "  -q  Loggable output - no progress indicator\n"
      "  -qq No output except for errors\n"
      "  -d  Download only - do NOT install or unpack archives\n"
      "  -s  No-act. Perform ordering simulation\n"
      "  -y  Assume Yes to all queries and do not prompt\n"
      "  -f  Attempt to correct a system with broken dependencies in place\n"
      "  -m  Attempt to continue if archives are unlocatable\n"
      "  -u  Show a list of upgraded packages as well\n"
      "  -b  Build the source package after fetching it\n"
      "  -V  Show verbose version numbers\n"
      "  -c=? Read this configuration file\n"
      "  -o=? Set an arbitrary configuration option, eg -o dir::cache=/tmp\n"
      "See the apt-get(8), sources.list(5) and apt.conf(5) manual\n"
      "pages for more information and options.\n"
      "                       This APT has Super Cow Powers.\n");
   return true;
}
                                                                        /*}}}*/
// SigWinch - Window size change signal handler                         /*{{{*/
// ---------------------------------------------------------------------
/* */
void SigWinch(int)
{
   // Riped from GNU ls
#ifdef TIOCGWINSZ
   struct winsize ws;
  
   if (ioctl(1, TIOCGWINSZ, &ws) != -1 && ws.ws_col >= 5)
      ScreenWidth = ws.ws_col - 1;
#endif
}
                                                                        /*}}}*/
bool DoUpgrade(CommandLine &CmdL)                                       /*{{{*/
{
   if (_config->FindB("APT::Get::UpgradeAllowNew", false) == true)
      return DoUpgradeWithAllowNewPackages(CmdL);
   else
      return DoUpgradeNoNewPackages(CmdL);
}
                                                                        /*}}}*/
int main(int argc,const char *argv[])                                   /*{{{*/
{
   CommandLine::Dispatch Cmds[] = {{"update",&DoUpdate},
                                   {"upgrade",&DoUpgrade},
                                   {"install",&DoInstall},
                                   {"remove",&DoInstall},
                                   {"purge",&DoInstall},
                                   {"autoremove",&DoInstall},
                                   {"markauto",&DoMarkAuto},
                                   {"unmarkauto",&DoMarkAuto},
                                   {"dist-upgrade",&DoDistUpgrade},
                                   {"dselect-upgrade",&DoDSelectUpgrade},
                                   {"build-dep",&DoBuildDep},
                                   {"clean",&DoClean},
                                   {"autoclean",&DoAutoClean},
                                   {"check",&DoCheck},
                                   {"source",&DoSource},
                                   {"download",&DoDownload},
                                   {"changelog",&DoChangelog},
                                   {"moo",&DoMoo},
                                   {"help",&ShowHelp},
                                   {0,0}};

   std::vector<CommandLine::Args> Args = getCommandArgs("apt-get", CommandLine::GetCommand(Cmds, argc, argv));

   // Set up gettext support
   setlocale(LC_ALL,"");
   textdomain(PACKAGE);

   // Parse the command line and initialize the package library
   CommandLine CmdL(Args.data(),_config);
   if (pkgInitConfig(*_config) == false ||
       CmdL.Parse(argc,argv) == false ||
       pkgInitSystem(*_config,_system) == false)
   {
      if (_config->FindB("version") == true)
         ShowHelp(CmdL);
         
      _error->DumpErrors();
      return 100;
   }

   // See if the help should be shown
   if (_config->FindB("help") == true ||
       _config->FindB("version") == true ||
       CmdL.FileSize() == 0)
   {
      ShowHelp(CmdL);
      return 0;
   }

   // see if we are in simulate mode
   CheckSimulateMode(CmdL);

   // Deal with stdout not being a tty
   if (!isatty(STDOUT_FILENO) && _config->FindI("quiet", -1) == -1)
      _config->Set("quiet","1");

   // Setup the output streams
   InitOutput();

   // Setup the signals
   signal(SIGPIPE,SIG_IGN);
   signal(SIGWINCH,SigWinch);
   SigWinch(0);

   // Match the operation
   CmdL.DispatchArg(Cmds);

   // Print any errors or warnings found during parsing
   bool const Errors = _error->PendingError();
   if (_config->FindI("quiet",0) > 0)
      _error->DumpErrors();
   else
      _error->DumpErrors(GlobalError::DEBUG);
   return Errors == true ? 100 : 0;
}
                                                                        /*}}}*/