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 and ButAutomaticUpgrades sources
  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 if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
  74          PFPriority[I->ID] = 100;
  75       else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  76          PFPriority[I->ID] = 1;
  77    }
  78
  79    // Apply the defaults..
  80    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  81    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  82    signed Cur = 989;
  83    StatusOverride = false;
  84    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  85         I++, Cur--)
  86    {
  87       pkgVersionMatch Match(I->Data,I->Type);
  88       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  89       {
  90          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  91          {
  92             if (I->Priority != 0 && I->Priority > 0)
  93                Cur = I->Priority;
  94
  95             if (I->Priority < 0)
  96                PFPriority[F->ID] =  I->Priority;
  97             else
  98                PFPriority[F->ID] = Cur;
  99
 100             if (PFPriority[F->ID] > 1000)
 101                StatusOverride = true;
 102
 103             Fixed[F->ID] = true;
 104          }
 105       }
 106    }
 107
 108    if (_config->FindB("Debug::pkgPolicy",false) == true)
 109       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 110          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 111
 112    return true;
 113 }
 114                                                                         /*}}}*/
 115 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 116 // ---------------------------------------------------------------------
 117 /* Evaluate the package pins and the default list to deteremine what the
 118    best package is. */
 119 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 120 {
 121    // Look for a package pin and evaluate it.
 122    signed Max = GetPriority(Pkg);
 123    pkgCache::VerIterator Pref = GetMatch(Pkg);
 124
 125    // Alternatives in case we can not find our package pin (Bug#512318).
 126    signed MaxAlt = 0;
 127    pkgCache::VerIterator PrefAlt;
 128
 129    // no package = no candidate version
 130    if (Pkg.end() == true)
 131       return Pref;
 132
 133    // packages with a pin lower than 0 have no newer candidate than the current version
 134    if (Max < 0)
 135       return Pkg.CurrentVer();
 136
 137    /* Falling through to the default version.. Setting Max to zero
 138       effectively excludes everything <= 0 which are the non-automatic
 139       priorities.. The status file is given a prio of 100 which will exclude
 140       not-automatic sources, except in a single shot not-installed mode.
 141       The second pseduo-status file is at prio 1000, above which will permit
 142       the user to force-downgrade things.
 143
 144       The user pin is subject to the same priority rules as default
 145       selections. Thus there are two ways to create a pin - a pin that
 146       tracks the default when the default is taken away, and a permanent
 147       pin that stays at that setting.
 148     */
 149    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 150    {
 151       /* Lets see if this version is the installed version */
 152       bool instVer = (Pkg.CurrentVer() == Ver);
 153       if (Ver.Pseudo() == true && instVer == false)
 154       {
 155          pkgCache::PkgIterator const allPkg = Ver.ParentPkg().Group().FindPkg("all");
 156          if (allPkg->CurrentVer != 0 && allPkg.CurrentVer()->Hash == Ver->Hash &&
 157              strcmp(allPkg.CurVersion(), Ver.VerStr()) == 0)
 158             instVer = true;
 159       }
 160
 161       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 162       {
 163          /* If this is the status file, and the current version is not the
 164             version in the status file (ie it is not installed, or somesuch)
 165             then it is not a candidate for installation, ever. This weeds
 166             out bogus entries that may be due to config-file states, or
 167             other. */
 168          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 169              instVer == false)
 170             continue;
 171
 172          signed Prio = PFPriority[VF.File()->ID];
 173          if (Prio > Max)
 174          {
 175             Pref = Ver;
 176             Max = Prio;
 177          }
 178          if (Prio > MaxAlt)
 179          {
 180             PrefAlt = Ver;
 181             MaxAlt = Prio;
 182          }
 183       }
 184
 185       if (instVer == true && Max < 1000)
 186       {
 187          /* Elevate our current selection (or the status file itself)
 188             to the Pseudo-status priority. */
 189          if (Pref.end() == true)
 190             Pref = Ver;
 191          Max = 1000;
 192
 193          // Fast path optimize.
 194          if (StatusOverride == false)
 195             break;
 196       }
 197    }
 198    // If we do not find our candidate, use the one with the highest pin.
 199    // This means that if there is a version available with pin > 0; there
 200    // will always be a candidate (Closes: #512318)
 201    if (!Pref.IsGood() && MaxAlt > 0)
 202        Pref = PrefAlt;
 203
 204    return Pref;
 205 }
 206                                                                         /*}}}*/
 207 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 208 // ---------------------------------------------------------------------
 209 /* For performance we have 3 tables, the default table, the main cache
 210    table (hashed to the cache). A blank package name indicates the pin
 211    belongs to the default table. Order of insertion matters here, the
 212    earlier defaults override later ones. */
 213 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 214                           string Data,signed short Priority)
 215 {
 216    if (Name.empty() == true)
 217    {
 218       Pin *P = &*Defaults.insert(Defaults.end(),PkgPin());
 219       P->Type = Type;
 220       P->Priority = Priority;
 221       P->Data = Data;
 222       return;
 223    }
 224
 225    // Get a spot to put the pin
 226    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 227    for (pkgCache::PkgIterator Pkg = Grp.FindPkg("any");
 228         Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 229    {
 230       Pin *P = 0;
 231       if (Pkg.end() == false)
 232          P = Pins + Pkg->ID;
 233       else
 234       {
 235          // Check the unmatched table
 236          for (vector<PkgPin>::iterator I = Unmatched.begin();
 237               I != Unmatched.end() && P == 0; I++)
 238             if (I->Pkg == Name)
 239                P = &*I;
 240
 241          if (P == 0)
 242             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 243       }
 244       P->Type = Type;
 245       P->Priority = Priority;
 246       P->Data = Data;
 247    }
 248 }
 249                                                                         /*}}}*/
 250 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 251 // ---------------------------------------------------------------------
 252 /* */
 253 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 254 {
 255    const Pin &PPkg = Pins[Pkg->ID];
 256    if (PPkg.Type == pkgVersionMatch::None)
 257       return pkgCache::VerIterator(*Pkg.Cache());
 258
 259    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 260    return Match.Find(Pkg);
 261 }
 262                                                                         /*}}}*/
 263 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 264 // ---------------------------------------------------------------------
 265 /* */
 266 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 267 {
 268    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 269    {
 270       // In this case 0 means default priority
 271       if (Pins[Pkg->ID].Priority == 0)
 272          return 989;
 273       return Pins[Pkg->ID].Priority;
 274    }
 275
 276    return 0;
 277 }
 278                                                                         /*}}}*/
 279 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 280 // ---------------------------------------------------------------------
 281 /* The preference file is a user generated file so the parser should
 282    therefore be a bit more friendly by allowing comments and new lines
 283    all over the place rather than forcing a special format */
 284 class PreferenceSection : public pkgTagSection
 285 {
 286    void TrimRecord(bool BeforeRecord, const char* &End)
 287    {
 288       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 289          if (Stop[0] == '#')
 290             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 291    }
 292 };
 293                                                                         /*}}}*/
 294 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 295 // ---------------------------------------------------------------------
 296 /* This will load each pin file in the given dir into a Policy. If the
 297    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 298    Note also that this method will issue a warning if the dir does not
 299    exists but it will return true in this case! */
 300 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 301 {
 302    if (Dir.empty() == true)
 303       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 304
 305    if (DirectoryExists(Dir) == false)
 306    {
 307       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 308       return true;
 309    }
 310
 311    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 312
 313    // Read the files
 314    for (vector<string>::const_iterator I = List.begin(); I != List.end(); I++)
 315       if (ReadPinFile(Plcy, *I) == false)
 316          return false;
 317    return true;
 318 }
 319                                                                         /*}}}*/
 320 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 321 // ---------------------------------------------------------------------
 322 /* I'd like to see the preferences file store more than just pin information
 323    but right now that is the only stuff I have to store. Later there will
 324    have to be some kind of combined super parser to get the data into all
 325    the right classes.. */
 326 bool ReadPinFile(pkgPolicy &Plcy,string File)
 327 {
 328    if (File.empty() == true)
 329       File = _config->FindFile("Dir::Etc::Preferences");
 330
 331    if (FileExists(File) == false)
 332       return true;
 333
 334    FileFd Fd(File,FileFd::ReadOnly);
 335    pkgTagFile TF(&Fd);
 336    if (_error->PendingError() == true)
 337       return false;
 338
 339    PreferenceSection Tags;
 340    while (TF.Step(Tags) == true)
 341    {
 342       string Name = Tags.FindS("Package");
 343       if (Name.empty() == true)
 344          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 345       if (Name == "*")
 346          Name = string();
 347
 348       const char *Start;
 349       const char *End;
 350       if (Tags.Find("Pin",Start,End) == false)
 351          continue;
 352
 353       const char *Word = Start;
 354       for (; Word != End && isspace(*Word) == 0; Word++);
 355
 356       // Parse the type..
 357       pkgVersionMatch::MatchType Type;
 358       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 359          Type = pkgVersionMatch::Version;
 360       else if (stringcasecmp(Start,Word,"release") == 0)
 361          Type = pkgVersionMatch::Release;
 362       else if (stringcasecmp(Start,Word,"origin") == 0)
 363          Type = pkgVersionMatch::Origin;
 364       else
 365       {
 366          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 367          continue;
 368       }
 369       for (; Word != End && isspace(*Word) != 0; Word++);
 370
 371       short int priority = Tags.FindI("Pin-Priority", 0);
 372       if (priority == 0)
 373       {
 374          _error->Warning(_("No priority (or zero) specified for pin"));
 375          continue;
 376       }
 377
 378       istringstream s(Name);
 379       string pkg;
 380       while(!s.eof())
 381       {
 382          s >> pkg;
 383          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 384       };
 385    }
 386
 387    Plcy.InitDefaults();
 388    return true;
 389 }
 390                                                                         /*}}}*/