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