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