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(),PkgPin());
 214       P->Type = Type;
 215       P->Priority = Priority;
 216       P->Data = Data;
 217       return;
 218    }
 219
 220    // Allow pinning by wildcards
 221    // TODO: Maybe we should always prefer specific pins over non-
 222    // specific ones.
 223    if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
 224    {
 225       pkgVersionMatch match(Data, Type);
 226       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 227          if (match.ExpressionMatches(Name, G.Name()))
 228             CreatePin(Type, G.Name(), Data, Priority);
 229       return;
 230    }
 231
 232    // Get a spot to put the pin
 233    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 234    for (pkgCache::PkgIterator Pkg = Grp.PackageList();
 235         Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 236    {
 237       Pin *P = 0;
 238       if (Pkg.end() == false)
 239          P = Pins + Pkg->ID;
 240       else
 241       {
 242          // Check the unmatched table
 243          for (vector<PkgPin>::iterator I = Unmatched.begin();
 244               I != Unmatched.end() && P == 0; I++)
 245             if (I->Pkg == Name)
 246                P = &*I;
 247
 248          if (P == 0)
 249             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 250       }
 251       P->Type = Type;
 252       P->Priority = Priority;
 253       P->Data = Data;
 254    }
 255 }
 256                                                                         /*}}}*/
 257 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 258 // ---------------------------------------------------------------------
 259 /* */
 260 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 261 {
 262    const Pin &PPkg = Pins[Pkg->ID];
 263    if (PPkg.Type == pkgVersionMatch::None)
 264       return pkgCache::VerIterator(*Pkg.Cache());
 265
 266    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 267    return Match.Find(Pkg);
 268 }
 269                                                                         /*}}}*/
 270 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 271 // ---------------------------------------------------------------------
 272 /* */
 273 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 274 {
 275    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 276    {
 277       // In this case 0 means default priority
 278       if (Pins[Pkg->ID].Priority == 0)
 279          return 989;
 280       return Pins[Pkg->ID].Priority;
 281    }
 282
 283    return 0;
 284 }
 285                                                                         /*}}}*/
 286 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 287 // ---------------------------------------------------------------------
 288 /* The preference file is a user generated file so the parser should
 289    therefore be a bit more friendly by allowing comments and new lines
 290    all over the place rather than forcing a special format */
 291 class PreferenceSection : public pkgTagSection
 292 {
 293    void TrimRecord(bool BeforeRecord, const char* &End)
 294    {
 295       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 296          if (Stop[0] == '#')
 297             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 298    }
 299 };
 300                                                                         /*}}}*/
 301 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 302 // ---------------------------------------------------------------------
 303 /* This will load each pin file in the given dir into a Policy. If the
 304    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 305    Note also that this method will issue a warning if the dir does not
 306    exists but it will return true in this case! */
 307 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 308 {
 309    if (Dir.empty() == true)
 310       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 311
 312    if (DirectoryExists(Dir) == false)
 313    {
 314       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 315       return true;
 316    }
 317
 318    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 319
 320    // Read the files
 321    for (vector<string>::const_iterator I = List.begin(); I != List.end(); I++)
 322       if (ReadPinFile(Plcy, *I) == false)
 323          return false;
 324    return true;
 325 }
 326                                                                         /*}}}*/
 327 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 328 // ---------------------------------------------------------------------
 329 /* I'd like to see the preferences file store more than just pin information
 330    but right now that is the only stuff I have to store. Later there will
 331    have to be some kind of combined super parser to get the data into all
 332    the right classes.. */
 333 bool ReadPinFile(pkgPolicy &Plcy,string File)
 334 {
 335    if (File.empty() == true)
 336       File = _config->FindFile("Dir::Etc::Preferences");
 337
 338    if (RealFileExists(File) == false)
 339       return true;
 340
 341    FileFd Fd(File,FileFd::ReadOnly);
 342    pkgTagFile TF(&Fd);
 343    if (_error->PendingError() == true)
 344       return false;
 345
 346    PreferenceSection Tags;
 347    while (TF.Step(Tags) == true)
 348    {
 349       string Name = Tags.FindS("Package");
 350       if (Name.empty() == true)
 351          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 352       if (Name == "*")
 353          Name = string();
 354
 355       const char *Start;
 356       const char *End;
 357       if (Tags.Find("Pin",Start,End) == false)
 358          continue;
 359
 360       const char *Word = Start;
 361       for (; Word != End && isspace(*Word) == 0; Word++);
 362
 363       // Parse the type..
 364       pkgVersionMatch::MatchType Type;
 365       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 366          Type = pkgVersionMatch::Version;
 367       else if (stringcasecmp(Start,Word,"release") == 0)
 368          Type = pkgVersionMatch::Release;
 369       else if (stringcasecmp(Start,Word,"origin") == 0)
 370          Type = pkgVersionMatch::Origin;
 371       else
 372       {
 373          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 374          continue;
 375       }
 376       for (; Word != End && isspace(*Word) != 0; Word++);
 377
 378       short int priority = Tags.FindI("Pin-Priority", 0);
 379       if (priority == 0)
 380       {
 381          _error->Warning(_("No priority (or zero) specified for pin"));
 382          continue;
 383       }
 384
 385       istringstream s(Name);
 386       string pkg;
 387       while(!s.eof())
 388       {
 389          s >> pkg;
 390          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 391       };
 392    }
 393
 394    Plcy.InitDefaults();
 395    return true;
 396 }
 397                                                                         /*}}}*/