apt-pkg/policy.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: policy.cc,v 1.10 2003/08/12 00:17:37 mdz Exp $
   4 /* ######################################################################
   5
   6    Package Version Policy implementation
   7
   8    This is just a really simple wrapper around pkgVersionMatch with
   9    some added goodies to manage the list of things..
  10
  11    Priority Table:
  12
  13    1000 -> inf = Downgradeable priorities
  14    1000        = The 'no downgrade' pseduo-status file
  15    100 -> 1000 = Standard priorities
  16    990         = Config file override package files
  17    989         = Start for preference auto-priorities
  18    500         = Default package files
  19    100         = The status file
  20    0 -> 100    = NotAutomatic sources like experimental
  21    -inf -> 0   = Never selected
  22
  23    ##################################################################### */
  24                                                                         /*}}}*/
  25 // Include Files                                                        /*{{{*/
  26 #include <apt-pkg/policy.h>
  27 #include <apt-pkg/configuration.h>
  28 #include <apt-pkg/tagfile.h>
  29 #include <apt-pkg/strutl.h>
  30 #include <apt-pkg/fileutl.h>
  31 #include <apt-pkg/error.h>
  32 #include <apt-pkg/sptr.h>
  33
  34 #include <apti18n.h>
  35
  36 #include <iostream>
  37 #include <sstream>
  38                                                                         /*}}}*/
  39
  40 using namespace std;
  41
  42 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  43 // ---------------------------------------------------------------------
  44 /* Set the defaults for operation. The default mode with no loaded policy
  45    file matches the V0 policy engine. */
  46 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  47 {
  48    PFPriority = new signed short[Owner->Head().PackageFileCount];
  49    Pins = new Pin[Owner->Head().PackageCount];
  50
  51    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  52       Pins[I].Type = pkgVersionMatch::None;
  53
  54    // The config file has a master override.
  55    string DefRel = _config->Find("APT::Default-Release");
  56    if (DefRel.empty() == false)
  57       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  58
  59    InitDefaults();
  60 }
  61                                                                         /*}}}*/
  62 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  63 // ---------------------------------------------------------------------
  64 /* */
  65 bool pkgPolicy::InitDefaults()
  66 {
  67    // Initialize the priorities based on the status of the package file
  68    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  69    {
  70       PFPriority[I->ID] = 500;
  71       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  72          PFPriority[I->ID] = 100;
  73       else
  74          if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  75             PFPriority[I->ID] = 1;
  76    }
  77
  78    // Apply the defaults..
  79    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  80    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  81    signed Cur = 989;
  82    StatusOverride = false;
  83    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  84         I++, Cur--)
  85    {
  86       pkgVersionMatch Match(I->Data,I->Type);
  87       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  88       {
  89          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  90          {
  91             if (I->Priority != 0 && I->Priority > 0)
  92                Cur = I->Priority;
  93
  94             if (I->Priority < 0)
  95                PFPriority[F->ID] =  I->Priority;
  96             else
  97                PFPriority[F->ID] = Cur;
  98
  99             if (PFPriority[F->ID] > 1000)
 100                StatusOverride = true;
 101
 102             Fixed[F->ID] = true;
 103          }
 104       }
 105    }
 106
 107    if (_config->FindB("Debug::pkgPolicy",false) == true)
 108       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 109          cout << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << endl;
 110
 111    return true;
 112 }
 113                                                                         /*}}}*/
 114 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 115 // ---------------------------------------------------------------------
 116 /* Evaluate the package pins and the default list to deteremine what the
 117    best package is. */
 118 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator Pkg)
 119 {
 120    // Look for a package pin and evaluate it.
 121    signed Max = GetPriority(Pkg);
 122    pkgCache::VerIterator Pref = GetMatch(Pkg);
 123
 124    // no package = no candidate version
 125    if (Pkg.end() == true)
 126       return Pref;
 127
 128    // packages with a pin lower than 0 have no newer candidate than the current version
 129    if (Max < 0)
 130       return Pkg.CurrentVer();
 131
 132    /* Falling through to the default version.. Setting Max to zero
 133       effectively excludes everything <= 0 which are the non-automatic
 134       priorities.. The status file is given a prio of 100 which will exclude
 135       not-automatic sources, except in a single shot not-installed mode.
 136       The second pseduo-status file is at prio 1000, above which will permit
 137       the user to force-downgrade things.
 138
 139       The user pin is subject to the same priority rules as default
 140       selections. Thus there are two ways to create a pin - a pin that
 141       tracks the default when the default is taken away, and a permanent
 142       pin that stays at that setting.
 143     */
 144    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 145    {
 146       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 147       {
 148          /* If this is the status file, and the current version is not the
 149             version in the status file (ie it is not installed, or somesuch)
 150             then it is not a candidate for installation, ever. This weeds
 151             out bogus entries that may be due to config-file states, or
 152             other. */
 153          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 154              Pkg.CurrentVer() != Ver)
 155             continue;
 156
 157          signed Prio = PFPriority[VF.File()->ID];
 158          if (Prio > Max)
 159          {
 160             Pref = Ver;
 161             Max = Prio;
 162          }
 163       }
 164
 165       if (Pkg.CurrentVer() == Ver && Max < 1000)
 166       {
 167          /* Elevate our current selection (or the status file itself)
 168             to the Pseudo-status priority. */
 169          if (Pref.end() == true)
 170             Pref = Ver;
 171          Max = 1000;
 172
 173          // Fast path optimize.
 174          if (StatusOverride == false)
 175             break;
 176       }
 177    }
 178    return Pref;
 179 }
 180                                                                         /*}}}*/
 181 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 182 // ---------------------------------------------------------------------
 183 /* For performance we have 3 tables, the default table, the main cache
 184    table (hashed to the cache). A blank package name indicates the pin
 185    belongs to the default table. Order of insertion matters here, the
 186    earlier defaults override later ones. */
 187 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 188                           string Data,signed short Priority)
 189 {
 190    if (Name.empty() == true)
 191    {
 192       Pin *P = &*Defaults.insert(Defaults.end(),PkgPin());
 193       P->Type = Type;
 194       P->Priority = Priority;
 195       P->Data = Data;
 196       return;
 197    }
 198
 199    // Get a spot to put the pin
 200    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 201    for (pkgCache::PkgIterator Pkg = Grp.FindPkg("any");
 202         Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 203    {
 204       Pin *P = 0;
 205       if (Pkg.end() == false)
 206          P = Pins + Pkg->ID;
 207       else
 208       {
 209          // Check the unmatched table
 210          for (vector<PkgPin>::iterator I = Unmatched.begin();
 211               I != Unmatched.end() && P == 0; I++)
 212             if (I->Pkg == Name)
 213                P = &*I;
 214
 215          if (P == 0)
 216             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 217       }
 218       P->Type = Type;
 219       P->Priority = Priority;
 220       P->Data = Data;
 221    }
 222 }
 223                                                                         /*}}}*/
 224 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 225 // ---------------------------------------------------------------------
 226 /* */
 227 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator Pkg)
 228 {
 229    const Pin &PPkg = Pins[Pkg->ID];
 230    if (PPkg.Type != pkgVersionMatch::None)
 231    {
 232       pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 233       return Match.Find(Pkg);
 234    }
 235    return pkgCache::VerIterator(*Pkg.Cache());
 236 }
 237                                                                         /*}}}*/
 238 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 239 // ---------------------------------------------------------------------
 240 /* */
 241 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 242 {
 243    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 244    {
 245       // In this case 0 means default priority
 246       if (Pins[Pkg->ID].Priority == 0)
 247          return 989;
 248       return Pins[Pkg->ID].Priority;
 249    }
 250
 251    return 0;
 252 }
 253                                                                         /*}}}*/
 254 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 255 // ---------------------------------------------------------------------
 256 /* The preference file is a user generated file so the parser should
 257    therefore be a bit more friendly by allowing comments and new lines
 258    all over the place rather than forcing a special format */
 259 class PreferenceSection : public pkgTagSection
 260 {
 261    void TrimRecord(bool BeforeRecord, const char* &End)
 262    {
 263       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 264          if (Stop[0] == '#')
 265             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 266    }
 267 };
 268                                                                         /*}}}*/
 269 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 270 // ---------------------------------------------------------------------
 271 /* This will load each pin file in the given dir into a Policy. If the
 272    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 273    Note also that this method will issue a warning if the dir does not
 274    exists but it will return true in this case! */
 275 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 276 {
 277    if (Dir.empty() == true)
 278       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 279
 280    if (FileExists(Dir) == false)
 281    {
 282       _error->WarningE("FileExists",_("Unable to read %s"),Dir.c_str());
 283       return true;
 284    }
 285
 286    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 287
 288    // Read the files
 289    for (vector<string>::const_iterator I = List.begin(); I != List.end(); I++)
 290       if (ReadPinFile(Plcy, *I) == false)
 291          return false;
 292    return true;
 293 }
 294                                                                         /*}}}*/
 295 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 296 // ---------------------------------------------------------------------
 297 /* I'd like to see the preferences file store more than just pin information
 298    but right now that is the only stuff I have to store. Later there will
 299    have to be some kind of combined super parser to get the data into all
 300    the right classes.. */
 301 bool ReadPinFile(pkgPolicy &Plcy,string File)
 302 {
 303    if (File.empty() == true)
 304       File = _config->FindFile("Dir::Etc::Preferences");
 305
 306    if (FileExists(File) == false)
 307       return true;
 308
 309    FileFd Fd(File,FileFd::ReadOnly);
 310    pkgTagFile TF(&Fd);
 311    if (_error->PendingError() == true)
 312       return false;
 313
 314    PreferenceSection Tags;
 315    while (TF.Step(Tags) == true)
 316    {
 317       string Name = Tags.FindS("Package");
 318       if (Name.empty() == true)
 319          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 320       if (Name == "*")
 321          Name = string();
 322
 323       const char *Start;
 324       const char *End;
 325       if (Tags.Find("Pin",Start,End) == false)
 326          continue;
 327
 328       const char *Word = Start;
 329       for (; Word != End && isspace(*Word) == 0; Word++);
 330
 331       // Parse the type..
 332       pkgVersionMatch::MatchType Type;
 333       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 334          Type = pkgVersionMatch::Version;
 335       else if (stringcasecmp(Start,Word,"release") == 0)
 336          Type = pkgVersionMatch::Release;
 337       else if (stringcasecmp(Start,Word,"origin") == 0)
 338          Type = pkgVersionMatch::Origin;
 339       else
 340       {
 341          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 342          continue;
 343       }
 344       for (; Word != End && isspace(*Word) != 0; Word++);
 345
 346       short int priority = Tags.FindI("Pin-Priority", 0);
 347       if (priority == 0)
 348       {
 349          _error->Warning(_("No priority (or zero) specified for pin"));
 350          continue;
 351       }
 352
 353       istringstream s(Name);
 354       string pkg;
 355       while(!s.eof())
 356       {
 357          s >> pkg;
 358          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 359       };
 360    }
 361
 362    Plcy.InitDefaults();
 363    return true;
 364 }
 365                                                                         /*}}}*/