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    See man apt_preferences for what value means what.
  12
  13    ##################################################################### */
  14                                                                         /*}}}*/
  15 // Include Files                                                        /*{{{*/
  16 #include<config.h>
  17
  18 #include <apt-pkg/policy.h>
  19 #include <apt-pkg/configuration.h>
  20 #include <apt-pkg/cachefilter.h>
  21 #include <apt-pkg/tagfile.h>
  22 #include <apt-pkg/strutl.h>
  23 #include <apt-pkg/fileutl.h>
  24 #include <apt-pkg/error.h>
  25 #include <apt-pkg/sptr.h>
  26 #include <apt-pkg/cacheiterators.h>
  27 #include <apt-pkg/pkgcache.h>
  28 #include <apt-pkg/versionmatch.h>
  29
  30 #include <ctype.h>
  31 #include <stddef.h>
  32 #include <string.h>
  33 #include <string>
  34 #include <vector>
  35 #include <iostream>
  36 #include <sstream>
  37
  38 #include <apti18n.h>
  39                                                                         /*}}}*/
  40
  41 using namespace std;
  42
  43 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  44 // ---------------------------------------------------------------------
  45 /* Set the defaults for operation. The default mode with no loaded policy
  46    file matches the V0 policy engine. */
  47 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  48 {
  49    if (Owner == 0)
  50       return;
  51    PFPriority = new signed short[Owner->Head().PackageFileCount];
  52    Pins = new Pin[Owner->Head().PackageCount];
  53
  54    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  55       Pins[I].Type = pkgVersionMatch::None;
  56
  57    // The config file has a master override.
  58    string DefRel = _config->Find("APT::Default-Release");
  59    if (DefRel.empty() == false)
  60    {
  61       bool found = false;
  62       // FIXME: make ExpressionMatches static to use it here easily
  63       pkgVersionMatch vm("", pkgVersionMatch::None);
  64       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
  65       {
  66          if ((F->Archive != 0 && vm.ExpressionMatches(DefRel, F.Archive()) == true) ||
  67              (F->Codename != 0 && vm.ExpressionMatches(DefRel, F.Codename()) == true) ||
  68              (F->Version != 0 && vm.ExpressionMatches(DefRel, F.Version()) == true) ||
  69              (DefRel.length() > 2 && DefRel[1] == '='))
  70             found = true;
  71       }
  72       if (found == false)
  73          _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
  74       else
  75          CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  76    }
  77    InitDefaults();
  78 }
  79                                                                         /*}}}*/
  80 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  81 // ---------------------------------------------------------------------
  82 /* */
  83 bool pkgPolicy::InitDefaults()
  84 {
  85    // Initialize the priorities based on the status of the package file
  86    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
  87    {
  88       PFPriority[I->ID] = 500;
  89       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  90          PFPriority[I->ID] = 100;
  91       else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
  92          PFPriority[I->ID] = 100;
  93       else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  94          PFPriority[I->ID] = 1;
  95    }
  96
  97    // Apply the defaults..
  98    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  99    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
 100    StatusOverride = false;
 101    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
 102    {
 103       pkgVersionMatch Match(I->Data,I->Type);
 104       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 105       {
 106          if (Fixed[F->ID] == false && Match.FileMatch(F) == true)
 107          {
 108             PFPriority[F->ID] = I->Priority;
 109
 110             if (PFPriority[F->ID] >= 1000)
 111                StatusOverride = true;
 112
 113             Fixed[F->ID] = true;
 114          }
 115       }
 116    }
 117
 118    if (_config->FindB("Debug::pkgPolicy",false) == true)
 119       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 120          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 121
 122    return true;
 123 }
 124                                                                         /*}}}*/
 125 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 126 // ---------------------------------------------------------------------
 127 /* Evaluate the package pins and the default list to deteremine what the
 128    best package is. */
 129 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 130 {
 131    // Look for a package pin and evaluate it.
 132    signed Max = GetPriority(Pkg);
 133    pkgCache::VerIterator Pref = GetMatch(Pkg);
 134
 135    // Alternatives in case we can not find our package pin (Bug#512318).
 136    signed MaxAlt = 0;
 137    pkgCache::VerIterator PrefAlt;
 138
 139    // no package = no candidate version
 140    if (Pkg.end() == true)
 141       return Pref;
 142
 143    // packages with a pin lower than 0 have no newer candidate than the current version
 144    if (Max < 0)
 145       return Pkg.CurrentVer();
 146
 147    /* Falling through to the default version.. Setting Max to zero
 148       effectively excludes everything <= 0 which are the non-automatic
 149       priorities.. The status file is given a prio of 100 which will exclude
 150       not-automatic sources, except in a single shot not-installed mode.
 151
 152       The user pin is subject to the same priority rules as default
 153       selections. Thus there are two ways to create a pin - a pin that
 154       tracks the default when the default is taken away, and a permanent
 155       pin that stays at that setting.
 156     */
 157    bool PrefSeen = false;
 158    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
 159    {
 160       /* Lets see if this version is the installed version */
 161       bool instVer = (Pkg.CurrentVer() == Ver);
 162
 163       if (Pref == Ver)
 164          PrefSeen = true;
 165
 166       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
 167       {
 168          /* If this is the status file, and the current version is not the
 169             version in the status file (ie it is not installed, or somesuch)
 170             then it is not a candidate for installation, ever. This weeds
 171             out bogus entries that may be due to config-file states, or
 172             other. */
 173          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 174              instVer == false)
 175             continue;
 176
 177          signed Prio = PFPriority[VF.File()->ID];
 178          if (Prio > Max)
 179          {
 180             Pref = Ver;
 181             Max = Prio;
 182             PrefSeen = true;
 183          }
 184          if (Prio > MaxAlt)
 185          {
 186             PrefAlt = Ver;
 187             MaxAlt = Prio;
 188          }
 189       }
 190
 191       if (instVer == true && Max < 1000)
 192       {
 193          /* Not having seen the Pref yet means we have a specific pin below 1000
 194             on a version below the current installed one, so ignore the specific pin
 195             as this would be a downgrade otherwise */
 196          if (PrefSeen == false || Pref.end() == true)
 197          {
 198             Pref = Ver;
 199             PrefSeen = true;
 200          }
 201          /* Elevate our current selection (or the status file itself) so that only
 202             a downgrade can override it from now on */
 203          Max = 999;
 204
 205          // Fast path optimize.
 206          if (StatusOverride == false)
 207             break;
 208       }
 209    }
 210    // If we do not find our candidate, use the one with the highest pin.
 211    // This means that if there is a version available with pin > 0; there
 212    // will always be a candidate (Closes: #512318)
 213    if (!Pref.IsGood() && MaxAlt > 0)
 214        Pref = PrefAlt;
 215
 216    return Pref;
 217 }
 218                                                                         /*}}}*/
 219 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 220 // ---------------------------------------------------------------------
 221 /* For performance we have 3 tables, the default table, the main cache
 222    table (hashed to the cache). A blank package name indicates the pin
 223    belongs to the default table. Order of insertion matters here, the
 224    earlier defaults override later ones. */
 225 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 226                           string Data,signed short Priority)
 227 {
 228    if (Name.empty() == true)
 229    {
 230       Pin *P = &*Defaults.insert(Defaults.end(),Pin());
 231       P->Type = Type;
 232       P->Priority = Priority;
 233       P->Data = Data;
 234       return;
 235    }
 236
 237    size_t found = Name.rfind(':');
 238    string Arch;
 239    if (found != string::npos) {
 240       Arch = Name.substr(found+1);
 241       Name.erase(found);
 242    }
 243
 244    // Allow pinning by wildcards
 245    // TODO: Maybe we should always prefer specific pins over non-
 246    // specific ones.
 247    if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
 248    {
 249       pkgVersionMatch match(Data, Type);
 250       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 251          if (match.ExpressionMatches(Name, G.Name()))
 252          {
 253             if (Arch.empty() == false)
 254                CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
 255             else
 256                CreatePin(Type, G.Name(), Data, Priority);
 257          }
 258       return;
 259    }
 260
 261    // find the package (group) this pin applies to
 262    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 263    bool matched = false;
 264    if (Grp.end() == false)
 265    {
 266       std::string MatchingArch;
 267       if (Arch.empty() == true)
 268          MatchingArch = Cache->NativeArch();
 269       else
 270          MatchingArch = Arch;
 271       APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
 272       for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 273       {
 274          if (pams(Pkg.Arch()) == false)
 275             continue;
 276          Pin *P = Pins + Pkg->ID;
 277          // the first specific stanza for a package is the ruler,
 278          // all others need to be ignored
 279          if (P->Type != pkgVersionMatch::None)
 280             P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 281          P->Type = Type;
 282          P->Priority = Priority;
 283          P->Data = Data;
 284          matched = true;
 285       }
 286    }
 287
 288    if (matched == false)
 289    {
 290       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 291       if (Arch.empty() == false)
 292          P->Pkg.append(":").append(Arch);
 293       P->Type = Type;
 294       P->Priority = Priority;
 295       P->Data = Data;
 296       return;
 297    }
 298 }
 299                                                                         /*}}}*/
 300 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 301 // ---------------------------------------------------------------------
 302 /* */
 303 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 304 {
 305    const Pin &PPkg = Pins[Pkg->ID];
 306    if (PPkg.Type == pkgVersionMatch::None)
 307       return pkgCache::VerIterator(*Pkg.Cache());
 308
 309    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 310    return Match.Find(Pkg);
 311 }
 312                                                                         /*}}}*/
 313 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 314 // ---------------------------------------------------------------------
 315 /* */
 316 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 317 {
 318    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 319       return Pins[Pkg->ID].Priority;
 320    return 0;
 321 }
 322 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 323 {
 324    return PFPriority[File->ID];
 325 }
 326                                                                         /*}}}*/
 327 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 328 // ---------------------------------------------------------------------
 329 /* The preference file is a user generated file so the parser should
 330    therefore be a bit more friendly by allowing comments and new lines
 331    all over the place rather than forcing a special format */
 332 class PreferenceSection : public pkgTagSection
 333 {
 334    void TrimRecord(bool /*BeforeRecord*/, const char* &End)
 335    {
 336       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 337          if (Stop[0] == '#')
 338             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 339    }
 340 };
 341                                                                         /*}}}*/
 342 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 343 // ---------------------------------------------------------------------
 344 /* This will load each pin file in the given dir into a Policy. If the
 345    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 346    Note also that this method will issue a warning if the dir does not
 347    exists but it will return true in this case! */
 348 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 349 {
 350    if (Dir.empty() == true)
 351       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 352
 353    if (DirectoryExists(Dir) == false)
 354    {
 355       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 356       return true;
 357    }
 358
 359    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 360
 361    // Read the files
 362    for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
 363       if (ReadPinFile(Plcy, *I) == false)
 364          return false;
 365    return true;
 366 }
 367                                                                         /*}}}*/
 368 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 369 // ---------------------------------------------------------------------
 370 /* I'd like to see the preferences file store more than just pin information
 371    but right now that is the only stuff I have to store. Later there will
 372    have to be some kind of combined super parser to get the data into all
 373    the right classes.. */
 374 bool ReadPinFile(pkgPolicy &Plcy,string File)
 375 {
 376    if (File.empty() == true)
 377       File = _config->FindFile("Dir::Etc::Preferences");
 378
 379    if (RealFileExists(File) == false)
 380       return true;
 381
 382    FileFd Fd(File,FileFd::ReadOnly);
 383    pkgTagFile TF(&Fd);
 384    if (_error->PendingError() == true)
 385       return false;
 386
 387    PreferenceSection Tags;
 388    while (TF.Step(Tags) == true)
 389    {
 390       // can happen when there are only comments in a record
 391       if (Tags.Count() == 0)
 392          continue;
 393
 394       string Name = Tags.FindS("Package");
 395       if (Name.empty() == true)
 396          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 397       if (Name == "*")
 398          Name = string();
 399
 400       const char *Start;
 401       const char *End;
 402       if (Tags.Find("Pin",Start,End) == false)
 403          continue;
 404
 405       const char *Word = Start;
 406       for (; Word != End && isspace(*Word) == 0; Word++);
 407
 408       // Parse the type..
 409       pkgVersionMatch::MatchType Type;
 410       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 411          Type = pkgVersionMatch::Version;
 412       else if (stringcasecmp(Start,Word,"release") == 0)
 413          Type = pkgVersionMatch::Release;
 414       else if (stringcasecmp(Start,Word,"origin") == 0)
 415          Type = pkgVersionMatch::Origin;
 416       else
 417       {
 418          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 419          continue;
 420       }
 421       for (; Word != End && isspace(*Word) != 0; Word++);
 422
 423       short int priority = Tags.FindI("Pin-Priority", 0);
 424       if (priority == 0)
 425       {
 426          _error->Warning(_("No priority (or zero) specified for pin"));
 427          continue;
 428       }
 429
 430       istringstream s(Name);
 431       string pkg;
 432       while(!s.eof())
 433       {
 434          s >> pkg;
 435          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 436       };
 437    }
 438
 439    Plcy.InitDefaults();
 440    return true;
 441 }
 442                                                                         /*}}}*/