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<config.h>
  27
  28 #include <apt-pkg/policy.h>
  29 #include <apt-pkg/configuration.h>
  30 #include <apt-pkg/tagfile.h>
  31 #include <apt-pkg/strutl.h>
  32 #include <apt-pkg/fileutl.h>
  33 #include <apt-pkg/error.h>
  34 #include <apt-pkg/sptr.h>
  35
  36 #include <iostream>
  37 #include <sstream>
  38
  39 #include <apti18n.h>
  40                                                                         /*}}}*/
  41
  42 using namespace std;
  43
  44 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  45 // ---------------------------------------------------------------------
  46 /* Set the defaults for operation. The default mode with no loaded policy
  47    file matches the V0 policy engine. */
  48 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  49 {
  50    if (Owner == 0 || &(Owner->Head()) == 0)
  51       return;
  52    PFPriority = new signed short[Owner->Head().PackageFileCount];
  53    Pins = new Pin[Owner->Head().PackageCount];
  54
  55    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  56       Pins[I].Type = pkgVersionMatch::None;
  57
  58    // The config file has a master override.
  59    string DefRel = _config->Find("APT::Default-Release");
  60    if (DefRel.empty() == false)
  61       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  62
  63    InitDefaults();
  64 }
  65                                                                         /*}}}*/
  66 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  67 // ---------------------------------------------------------------------
  68 /* */
  69 bool pkgPolicy::InitDefaults()
  70 {
  71    // Initialize the priorities based on the status of the package file
  72    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  73    {
  74       PFPriority[I->ID] = 500;
  75       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  76          PFPriority[I->ID] = 100;
  77       else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
  78          PFPriority[I->ID] = 100;
  79       else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  80          PFPriority[I->ID] = 1;
  81    }
  82
  83    // Apply the defaults..
  84    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  85    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  86    signed Cur = 989;
  87    StatusOverride = false;
  88    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  89         I++, Cur--)
  90    {
  91       pkgVersionMatch Match(I->Data,I->Type);
  92       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  93       {
  94          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  95          {
  96             if (I->Priority != 0 && I->Priority > 0)
  97                Cur = I->Priority;
  98
  99             if (I->Priority < 0)
 100                PFPriority[F->ID] =  I->Priority;
 101             else
 102                PFPriority[F->ID] = Cur;
 103
 104             if (PFPriority[F->ID] > 1000)
 105                StatusOverride = true;
 106
 107             Fixed[F->ID] = true;
 108          }
 109       }
 110    }
 111
 112    if (_config->FindB("Debug::pkgPolicy",false) == true)
 113       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 114          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 115
 116    return true;
 117 }
 118                                                                         /*}}}*/
 119 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 120 // ---------------------------------------------------------------------
 121 /* Evaluate the package pins and the default list to deteremine what the
 122    best package is. */
 123 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 124 {
 125    // Look for a package pin and evaluate it.
 126    signed Max = GetPriority(Pkg);
 127    pkgCache::VerIterator Pref = GetMatch(Pkg);
 128
 129    // Alternatives in case we can not find our package pin (Bug#512318).
 130    signed MaxAlt = 0;
 131    pkgCache::VerIterator PrefAlt;
 132
 133    // no package = no candidate version
 134    if (Pkg.end() == true)
 135       return Pref;
 136
 137    // packages with a pin lower than 0 have no newer candidate than the current version
 138    if (Max < 0)
 139       return Pkg.CurrentVer();
 140
 141    /* Falling through to the default version.. Setting Max to zero
 142       effectively excludes everything <= 0 which are the non-automatic
 143       priorities.. The status file is given a prio of 100 which will exclude
 144       not-automatic sources, except in a single shot not-installed mode.
 145       The second pseduo-status file is at prio 1000, above which will permit
 146       the user to force-downgrade things.
 147
 148       The user pin is subject to the same priority rules as default
 149       selections. Thus there are two ways to create a pin - a pin that
 150       tracks the default when the default is taken away, and a permanent
 151       pin that stays at that setting.
 152     */
 153    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 154    {
 155       /* Lets see if this version is the installed version */
 156       bool instVer = (Pkg.CurrentVer() == Ver);
 157
 158       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 159       {
 160          /* If this is the status file, and the current version is not the
 161             version in the status file (ie it is not installed, or somesuch)
 162             then it is not a candidate for installation, ever. This weeds
 163             out bogus entries that may be due to config-file states, or
 164             other. */
 165          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 166              instVer == false)
 167             continue;
 168
 169          signed Prio = PFPriority[VF.File()->ID];
 170          if (Prio > Max)
 171          {
 172             Pref = Ver;
 173             Max = Prio;
 174          }
 175          if (Prio > MaxAlt)
 176          {
 177             PrefAlt = Ver;
 178             MaxAlt = Prio;
 179          }
 180       }
 181
 182       if (instVer == true && Max < 1000)
 183       {
 184          /* Elevate our current selection (or the status file itself)
 185             to the Pseudo-status priority. */
 186          if (Pref.end() == true)
 187             Pref = Ver;
 188          Max = 1000;
 189
 190          // Fast path optimize.
 191          if (StatusOverride == false)
 192             break;
 193       }
 194    }
 195    // If we do not find our candidate, use the one with the highest pin.
 196    // This means that if there is a version available with pin > 0; there
 197    // will always be a candidate (Closes: #512318)
 198    if (!Pref.IsGood() && MaxAlt > 0)
 199        Pref = PrefAlt;
 200
 201    return Pref;
 202 }
 203                                                                         /*}}}*/
 204 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 205 // ---------------------------------------------------------------------
 206 /* For performance we have 3 tables, the default table, the main cache
 207    table (hashed to the cache). A blank package name indicates the pin
 208    belongs to the default table. Order of insertion matters here, the
 209    earlier defaults override later ones. */
 210 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 211                           string Data,signed short Priority)
 212 {
 213    if (Name.empty() == true)
 214    {
 215       Pin *P = &*Defaults.insert(Defaults.end(),Pin());
 216       P->Type = Type;
 217       P->Priority = Priority;
 218       P->Data = Data;
 219       return;
 220    }
 221
 222    size_t found = Name.rfind(':');
 223    string Arch;
 224    if (found != string::npos) {
 225       Arch = Name.substr(found+1);
 226       Name.erase(found);
 227    }
 228
 229    // Allow pinning by wildcards
 230    // TODO: Maybe we should always prefer specific pins over non-
 231    // specific ones.
 232    if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
 233    {
 234       pkgVersionMatch match(Data, Type);
 235       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 236          if (match.ExpressionMatches(Name, G.Name()))
 237          {
 238             if (Arch.empty() == false)
 239                CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
 240             else
 241                CreatePin(Type, G.Name(), Data, Priority);
 242          }
 243       return;
 244    }
 245
 246    // find the package (group) this pin applies to
 247    pkgCache::GrpIterator Grp;
 248    pkgCache::PkgIterator Pkg;
 249    if (Arch.empty() == false)
 250       Pkg = Cache->FindPkg(Name, Arch);
 251    else {
 252       Grp = Cache->FindGrp(Name);
 253       if (Grp.end() == false)
 254          Pkg = Grp.PackageList();
 255    }
 256
 257    if (Pkg.end() == true)
 258    {
 259       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 260       if (Arch.empty() == false)
 261          P->Pkg.append(":").append(Arch);
 262       P->Type = Type;
 263       P->Priority = Priority;
 264       P->Data = Data;
 265       return;
 266    }
 267
 268    for (; Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 269    {
 270       Pin *P = Pins + Pkg->ID;
 271       // the first specific stanza for a package is the ruler,
 272       // all others need to be ignored
 273       if (P->Type != pkgVersionMatch::None)
 274          P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 275       P->Type = Type;
 276       P->Priority = Priority;
 277       P->Data = Data;
 278       if (Grp.end() == true)
 279          break;
 280    }
 281 }
 282                                                                         /*}}}*/
 283 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 284 // ---------------------------------------------------------------------
 285 /* */
 286 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 287 {
 288    const Pin &PPkg = Pins[Pkg->ID];
 289    if (PPkg.Type == pkgVersionMatch::None)
 290       return pkgCache::VerIterator(*Pkg.Cache());
 291
 292    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 293    return Match.Find(Pkg);
 294 }
 295                                                                         /*}}}*/
 296 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 297 // ---------------------------------------------------------------------
 298 /* */
 299 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 300 {
 301    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 302    {
 303       // In this case 0 means default priority
 304       if (Pins[Pkg->ID].Priority == 0)
 305          return 989;
 306       return Pins[Pkg->ID].Priority;
 307    }
 308
 309    return 0;
 310 }
 311 signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 312 {
 313    return PFPriority[File->ID];
 314 }
 315                                                                         /*}}}*/
 316 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 317 // ---------------------------------------------------------------------
 318 /* The preference file is a user generated file so the parser should
 319    therefore be a bit more friendly by allowing comments and new lines
 320    all over the place rather than forcing a special format */
 321 class PreferenceSection : public pkgTagSection
 322 {
 323    void TrimRecord(bool BeforeRecord, const char* &End)
 324    {
 325       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 326          if (Stop[0] == '#')
 327             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 328    }
 329 };
 330                                                                         /*}}}*/
 331 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 332 // ---------------------------------------------------------------------
 333 /* This will load each pin file in the given dir into a Policy. If the
 334    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 335    Note also that this method will issue a warning if the dir does not
 336    exists but it will return true in this case! */
 337 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 338 {
 339    if (Dir.empty() == true)
 340       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 341
 342    if (DirectoryExists(Dir) == false)
 343    {
 344       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 345       return true;
 346    }
 347
 348    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 349
 350    // Read the files
 351    for (vector<string>::const_iterator I = List.begin(); I != List.end(); I++)
 352       if (ReadPinFile(Plcy, *I) == false)
 353          return false;
 354    return true;
 355 }
 356                                                                         /*}}}*/
 357 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 358 // ---------------------------------------------------------------------
 359 /* I'd like to see the preferences file store more than just pin information
 360    but right now that is the only stuff I have to store. Later there will
 361    have to be some kind of combined super parser to get the data into all
 362    the right classes.. */
 363 bool ReadPinFile(pkgPolicy &Plcy,string File)
 364 {
 365    if (File.empty() == true)
 366       File = _config->FindFile("Dir::Etc::Preferences");
 367
 368    if (RealFileExists(File) == false)
 369       return true;
 370
 371    FileFd Fd(File,FileFd::ReadOnly);
 372    pkgTagFile TF(&Fd);
 373    if (_error->PendingError() == true)
 374       return false;
 375
 376    PreferenceSection Tags;
 377    while (TF.Step(Tags) == true)
 378    {
 379       string Name = Tags.FindS("Package");
 380       if (Name.empty() == true)
 381          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 382       if (Name == "*")
 383          Name = string();
 384
 385       const char *Start;
 386       const char *End;
 387       if (Tags.Find("Pin",Start,End) == false)
 388          continue;
 389
 390       const char *Word = Start;
 391       for (; Word != End && isspace(*Word) == 0; Word++);
 392
 393       // Parse the type..
 394       pkgVersionMatch::MatchType Type;
 395       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 396          Type = pkgVersionMatch::Version;
 397       else if (stringcasecmp(Start,Word,"release") == 0)
 398          Type = pkgVersionMatch::Release;
 399       else if (stringcasecmp(Start,Word,"origin") == 0)
 400          Type = pkgVersionMatch::Origin;
 401       else
 402       {
 403          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 404          continue;
 405       }
 406       for (; Word != End && isspace(*Word) != 0; Word++);
 407
 408       short int priority = Tags.FindI("Pin-Priority", 0);
 409       if (priority == 0)
 410       {
 411          _error->Warning(_("No priority (or zero) specified for pin"));
 412          continue;
 413       }
 414
 415       istringstream s(Name);
 416       string pkg;
 417       while(!s.eof())
 418       {
 419          s >> pkg;
 420          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 421       };
 422    }
 423
 424    Plcy.InitDefaults();
 425    return true;
 426 }
 427                                                                         /*}}}*/