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/error.h>
  31 #include <apt-pkg/sptr.h>
  32
  33 #include <apti18n.h>
  34
  35 #include <iostream>
  36 #include <sstream>
  37                                                                         /*}}}*/
  38
  39 using namespace std;
  40
  41 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  42 // ---------------------------------------------------------------------
  43 /* Set the defaults for operation. The default mode with no loaded policy
  44    file matches the V0 policy engine. */
  45 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  46 {
  47    PFPriority = new signed short[Owner->Head().PackageFileCount];
  48    Pins = new Pin[Owner->Head().PackageCount];
  49
  50    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  51       Pins[I].Type = pkgVersionMatch::None;
  52
  53    // The config file has a master override.
  54    string DefRel = _config->Find("APT::Default-Release");
  55    if (DefRel.empty() == false)
  56       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  57
  58    InitDefaults();
  59 }
  60                                                                         /*}}}*/
  61 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  62 // ---------------------------------------------------------------------
  63 /* */
  64 bool pkgPolicy::InitDefaults()
  65 {
  66    // Initialize the priorities based on the status of the package file
  67    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  68    {
  69       PFPriority[I->ID] = 500;
  70       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  71          PFPriority[I->ID] = 100;
  72       else
  73          if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  74             PFPriority[I->ID] = 1;
  75    }
  76
  77    // Apply the defaults..
  78    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  79    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  80    signed Cur = 989;
  81    StatusOverride = false;
  82    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  83         I++, Cur--)
  84    {
  85       pkgVersionMatch Match(I->Data,I->Type);
  86       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  87       {
  88          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  89          {
  90             if (I->Priority != 0 && I->Priority > 0)
  91                Cur = I->Priority;
  92
  93             if (I->Priority < 0)
  94                PFPriority[F->ID] =  I->Priority;
  95             else
  96                PFPriority[F->ID] = Cur;
  97
  98             if (PFPriority[F->ID] > 1000)
  99                StatusOverride = true;
 100
 101             Fixed[F->ID] = true;
 102          }
 103       }
 104    }
 105
 106    if (_config->FindB("Debug::pkgPolicy",false) == true)
 107       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 108          cout << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << endl;
 109
 110    return true;
 111 }
 112                                                                         /*}}}*/
 113 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 114 // ---------------------------------------------------------------------
 115 /* Evaluate the package pins and the default list to deteremine what the
 116    best package is. */
 117 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator Pkg)
 118 {
 119    // Look for a package pin and evaluate it.
 120    signed Max = GetPriority(Pkg);
 121    pkgCache::VerIterator Pref = GetMatch(Pkg);
 122
 123    // no package = no candidate version
 124    if (Pkg.end() == true)
 125       return Pref;
 126
 127    // packages with a pin lower than 0 have no newer candidate than the current version
 128    if (Max < 0)
 129       return Pkg.CurrentVer();
 130
 131    /* Falling through to the default version.. Setting Max to zero
 132       effectively excludes everything <= 0 which are the non-automatic
 133       priorities.. The status file is given a prio of 100 which will exclude
 134       not-automatic sources, except in a single shot not-installed mode.
 135       The second pseduo-status file is at prio 1000, above which will permit
 136       the user to force-downgrade things.
 137
 138       The user pin is subject to the same priority rules as default
 139       selections. Thus there are two ways to create a pin - a pin that
 140       tracks the default when the default is taken away, and a permanent
 141       pin that stays at that setting.
 142     */
 143    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 144    {
 145       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 146       {
 147          /* If this is the status file, and the current version is not the
 148             version in the status file (ie it is not installed, or somesuch)
 149             then it is not a candidate for installation, ever. This weeds
 150             out bogus entries that may be due to config-file states, or
 151             other. */
 152          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 153              Pkg.CurrentVer() != Ver)
 154             continue;
 155
 156          signed Prio = PFPriority[VF.File()->ID];
 157          if (Prio > Max)
 158          {
 159             Pref = Ver;
 160             Max = Prio;
 161          }
 162       }
 163
 164       if (Pkg.CurrentVer() == Ver && Max < 1000)
 165       {
 166          /* Elevate our current selection (or the status file itself)
 167             to the Pseudo-status priority. */
 168          if (Pref.end() == true)
 169             Pref = Ver;
 170          Max = 1000;
 171
 172          // Fast path optimize.
 173          if (StatusOverride == false)
 174             break;
 175       }
 176    }
 177    return Pref;
 178 }
 179                                                                         /*}}}*/
 180 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 181 // ---------------------------------------------------------------------
 182 /* For performance we have 3 tables, the default table, the main cache
 183    table (hashed to the cache). A blank package name indicates the pin
 184    belongs to the default table. Order of insertion matters here, the
 185    earlier defaults override later ones. */
 186 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 187                           string Data,signed short Priority)
 188 {
 189    Pin *P = 0;
 190
 191    if (Name.empty() == true)
 192       P = &*Defaults.insert(Defaults.end(),PkgPin());
 193    else
 194    {
 195       // Get a spot to put the pin
 196       pkgCache::PkgIterator Pkg = Cache->FindPkg(Name);
 197       if (Pkg.end() == true)
 198       {
 199          // Check the unmatched table
 200          for (vector<PkgPin>::iterator I = Unmatched.begin();
 201               I != Unmatched.end() && P == 0; I++)
 202             if (I->Pkg == Name)
 203                P = &*I;
 204
 205          if (P == 0)
 206             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 207       }
 208       else
 209       {
 210          P = Pins + Pkg->ID;
 211       }
 212    }
 213
 214    // Set..
 215    P->Type = Type;
 216    P->Priority = Priority;
 217    P->Data = Data;
 218 }
 219                                                                         /*}}}*/
 220 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 221 // ---------------------------------------------------------------------
 222 /* */
 223 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator Pkg)
 224 {
 225    const Pin &PPkg = Pins[Pkg->ID];
 226    if (PPkg.Type != pkgVersionMatch::None)
 227    {
 228       pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 229       return Match.Find(Pkg);
 230    }
 231    return pkgCache::VerIterator(*Pkg.Cache());
 232 }
 233                                                                         /*}}}*/
 234 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 235 // ---------------------------------------------------------------------
 236 /* */
 237 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 238 {
 239    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 240    {
 241       // In this case 0 means default priority
 242       if (Pins[Pkg->ID].Priority == 0)
 243          return 989;
 244       return Pins[Pkg->ID].Priority;
 245    }
 246
 247    return 0;
 248 }
 249                                                                         /*}}}*/
 250 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 251 // ---------------------------------------------------------------------
 252 /* The preference file is a user generated file so the parser should
 253    therefore be a bit more friendly by allowing comments and new lines
 254    all over the place rather than forcing a special format */
 255 class PreferenceSection : public pkgTagSection
 256 {
 257    void TrimRecord(bool BeforeRecord, const char* &End)
 258    {
 259       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 260          if (Stop[0] == '#')
 261             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 262    }
 263 };
 264                                                                         /*}}}*/
 265 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 266 // ---------------------------------------------------------------------
 267 /* I'd like to see the preferences file store more than just pin information
 268    but right now that is the only stuff I have to store. Later there will
 269    have to be some kind of combined super parser to get the data into all
 270    the right classes.. */
 271 bool ReadPinFile(pkgPolicy &Plcy,string File)
 272 {
 273    if (File.empty() == true)
 274       File = _config->FindFile("Dir::Etc::Preferences");
 275
 276    if (FileExists(File) == false)
 277       return true;
 278
 279    FileFd Fd(File,FileFd::ReadOnly);
 280    pkgTagFile TF(&Fd);
 281    if (_error->PendingError() == true)
 282       return false;
 283
 284    PreferenceSection Tags;
 285    while (TF.Step(Tags) == true)
 286    {
 287       string Name = Tags.FindS("Package");
 288       if (Name.empty() == true)
 289          return _error->Error(_("Invalid record in the preferences file, no Package header"));
 290       if (Name == "*")
 291          Name = string();
 292
 293       const char *Start;
 294       const char *End;
 295       if (Tags.Find("Pin",Start,End) == false)
 296          continue;
 297
 298       const char *Word = Start;
 299       for (; Word != End && isspace(*Word) == 0; Word++);
 300
 301       // Parse the type..
 302       pkgVersionMatch::MatchType Type;
 303       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 304          Type = pkgVersionMatch::Version;
 305       else if (stringcasecmp(Start,Word,"release") == 0)
 306          Type = pkgVersionMatch::Release;
 307       else if (stringcasecmp(Start,Word,"origin") == 0)
 308          Type = pkgVersionMatch::Origin;
 309       else
 310       {
 311          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 312          continue;
 313       }
 314       for (; Word != End && isspace(*Word) != 0; Word++);
 315
 316       short int priority = Tags.FindI("Pin-Priority", 0);
 317       if (priority == 0)
 318       {
 319          _error->Warning(_("No priority (or zero) specified for pin"));
 320          continue;
 321       }
 322
 323       istringstream s(Name);
 324       string pkg;
 325       while(!s.eof())
 326       {
 327          s >> pkg;
 328          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 329       };
 330    }
 331
 332    Plcy.InitDefaults();
 333    return true;
 334 }
 335                                                                         /*}}}*/