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          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::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 const &Pkg)
 119 {
 120    // Look for a package pin and evaluate it.
 121    signed Max = GetPriority(Pkg);
 122    pkgCache::VerIterator Pref = GetMatch(Pkg);
 123
 124    // Alternatives in case we can not find our package pin (Bug#512318).
 125    signed MaxAlt = 0;
 126    pkgCache::VerIterator PrefAlt;
 127
 128    // no package = no candidate version
 129    if (Pkg.end() == true)
 130       return Pref;
 131
 132    // packages with a pin lower than 0 have no newer candidate than the current version
 133    if (Max < 0)
 134       return Pkg.CurrentVer();
 135
 136    /* Falling through to the default version.. Setting Max to zero
 137       effectively excludes everything <= 0 which are the non-automatic
 138       priorities.. The status file is given a prio of 100 which will exclude
 139       not-automatic sources, except in a single shot not-installed mode.
 140       The second pseduo-status file is at prio 1000, above which will permit
 141       the user to force-downgrade things.
 142
 143       The user pin is subject to the same priority rules as default
 144       selections. Thus there are two ways to create a pin - a pin that
 145       tracks the default when the default is taken away, and a permanent
 146       pin that stays at that setting.
 147     */
 148    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 149    {
 150       /* Lets see if this version is the installed version */
 151       bool instVer = (Pkg.CurrentVer() == Ver);
 152       if (Ver.Pseudo() == true && instVer == false)
 153       {
 154          pkgCache::PkgIterator const allPkg = Ver.ParentPkg().Group().FindPkg("all");
 155          if (allPkg->CurrentVer != 0 && allPkg.CurrentVer()->Hash == Ver->Hash &&
 156              strcmp(allPkg.CurVersion(), Ver.VerStr()) == 0)
 157             instVer = true;
 158       }
 159
 160       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 161       {
 162          /* If this is the status file, and the current version is not the
 163             version in the status file (ie it is not installed, or somesuch)
 164             then it is not a candidate for installation, ever. This weeds
 165             out bogus entries that may be due to config-file states, or
 166             other. */
 167          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 168              instVer == false)
 169             continue;
 170
 171          signed Prio = PFPriority[VF.File()->ID];
 172          if (Prio > Max)
 173          {
 174             Pref = Ver;
 175             Max = Prio;
 176          }
 177          if (Prio > MaxAlt)
 178          {
 179             PrefAlt = Ver;
 180             MaxAlt = Prio;
 181          }
 182       }
 183
 184       if (instVer == true && Max < 1000)
 185       {
 186          /* Elevate our current selection (or the status file itself)
 187             to the Pseudo-status priority. */
 188          if (Pref.end() == true)
 189             Pref = Ver;
 190          Max = 1000;
 191
 192          // Fast path optimize.
 193          if (StatusOverride == false)
 194             break;
 195       }
 196    }
 197    // If we do not find our candidate, use the one with the highest pin.
 198    // This means that if there is a version available with pin > 0; there
 199    // will always be a candidate (Closes: #512318)
 200    if (!Pref.IsGood() && MaxAlt > 0)
 201        Pref = PrefAlt;
 202
 203    return Pref;
 204 }
 205                                                                         /*}}}*/
 206 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 207 // ---------------------------------------------------------------------
 208 /* For performance we have 3 tables, the default table, the main cache
 209    table (hashed to the cache). A blank package name indicates the pin
 210    belongs to the default table. Order of insertion matters here, the
 211    earlier defaults override later ones. */
 212 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 213                           string Data,signed short Priority)
 214 {
 215    if (Name.empty() == true)
 216    {
 217       Pin *P = &*Defaults.insert(Defaults.end(),PkgPin());
 218       P->Type = Type;
 219       P->Priority = Priority;
 220       P->Data = Data;
 221       return;
 222    }
 223
 224    // Get a spot to put the pin
 225    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 226    for (pkgCache::PkgIterator Pkg = Grp.FindPkg("any");
 227         Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 228    {
 229       Pin *P = 0;
 230       if (Pkg.end() == false)
 231          P = Pins + Pkg->ID;
 232       else
 233       {
 234          // Check the unmatched table
 235          for (vector<PkgPin>::iterator I = Unmatched.begin();
 236               I != Unmatched.end() && P == 0; I++)
 237             if (I->Pkg == Name)
 238                P = &*I;
 239
 240          if (P == 0)
 241             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 242       }
 243       P->Type = Type;
 244       P->Priority = Priority;
 245       P->Data = Data;
 246    }
 247 }
 248                                                                         /*}}}*/
 249 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 250 // ---------------------------------------------------------------------
 251 /* */
 252 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 253 {
 254    const Pin &PPkg = Pins[Pkg->ID];
 255    if (PPkg.Type == pkgVersionMatch::None)
 256       return pkgCache::VerIterator(*Pkg.Cache());
 257
 258    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 259    return Match.Find(Pkg);
 260 }
 261                                                                         /*}}}*/
 262 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 263 // ---------------------------------------------------------------------
 264 /* */
 265 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 266 {
 267    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 268    {
 269       // In this case 0 means default priority
 270       if (Pins[Pkg->ID].Priority == 0)
 271          return 989;
 272       return Pins[Pkg->ID].Priority;
 273    }
 274
 275    return 0;
 276 }
 277                                                                         /*}}}*/
 278 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 279 // ---------------------------------------------------------------------
 280 /* The preference file is a user generated file so the parser should
 281    therefore be a bit more friendly by allowing comments and new lines
 282    all over the place rather than forcing a special format */
 283 class PreferenceSection : public pkgTagSection
 284 {
 285    void TrimRecord(bool BeforeRecord, const char* &End)
 286    {
 287       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 288          if (Stop[0] == '#')
 289             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 290    }
 291 };
 292                                                                         /*}}}*/
 293 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 294 // ---------------------------------------------------------------------
 295 /* This will load each pin file in the given dir into a Policy. If the
 296    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 297    Note also that this method will issue a warning if the dir does not
 298    exists but it will return true in this case! */
 299 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 300 {
 301    if (Dir.empty() == true)
 302       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 303
 304    if (DirectoryExists(Dir) == false)
 305    {
 306       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 307       return true;
 308    }
 309
 310    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 311
 312    // Read the files
 313    for (vector<string>::const_iterator I = List.begin(); I != List.end(); I++)
 314       if (ReadPinFile(Plcy, *I) == false)
 315          return false;
 316    return true;
 317 }
 318                                                                         /*}}}*/
 319 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 320 // ---------------------------------------------------------------------
 321 /* I'd like to see the preferences file store more than just pin information
 322    but right now that is the only stuff I have to store. Later there will
 323    have to be some kind of combined super parser to get the data into all
 324    the right classes.. */
 325 bool ReadPinFile(pkgPolicy &Plcy,string File)
 326 {
 327    if (File.empty() == true)
 328       File = _config->FindFile("Dir::Etc::Preferences");
 329
 330    if (FileExists(File) == false)
 331       return true;
 332
 333    FileFd Fd(File,FileFd::ReadOnly);
 334    pkgTagFile TF(&Fd);
 335    if (_error->PendingError() == true)
 336       return false;
 337
 338    PreferenceSection Tags;
 339    while (TF.Step(Tags) == true)
 340    {
 341       string Name = Tags.FindS("Package");
 342       if (Name.empty() == true)
 343          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 344       if (Name == "*")
 345          Name = string();
 346
 347       const char *Start;
 348       const char *End;
 349       if (Tags.Find("Pin",Start,End) == false)
 350          continue;
 351
 352       const char *Word = Start;
 353       for (; Word != End && isspace(*Word) == 0; Word++);
 354
 355       // Parse the type..
 356       pkgVersionMatch::MatchType Type;
 357       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 358          Type = pkgVersionMatch::Version;
 359       else if (stringcasecmp(Start,Word,"release") == 0)
 360          Type = pkgVersionMatch::Release;
 361       else if (stringcasecmp(Start,Word,"origin") == 0)
 362          Type = pkgVersionMatch::Origin;
 363       else
 364       {
 365          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 366          continue;
 367       }
 368       for (; Word != End && isspace(*Word) != 0; Word++);
 369
 370       short int priority = Tags.FindI("Pin-Priority", 0);
 371       if (priority == 0)
 372       {
 373          _error->Warning(_("No priority (or zero) specified for pin"));
 374          continue;
 375       }
 376
 377       istringstream s(Name);
 378       string pkg;
 379       while(!s.eof())
 380       {
 381          s >> pkg;
 382          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 383       };
 384    }
 385
 386    Plcy.InitDefaults();
 387    return true;
 388 }
 389                                                                         /*}}}*/