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 <dirent.h>
  36 #include <sys/stat.h>
  37 #include <algorithm>
  38 #include <iostream>
  39 #include <sstream>
  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    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
  76          if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  77             PFPriority[I->ID] = 1;
  78    }
  79
  80    // Apply the defaults..
  81    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  82    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  83    signed Cur = 989;
  84    StatusOverride = false;
  85    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  86         I++, Cur--)
  87    {
  88       pkgVersionMatch Match(I->Data,I->Type);
  89       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  90       {
  91          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  92          {
  93             if (I->Priority != 0 && I->Priority > 0)
  94                Cur = I->Priority;
  95
  96             if (I->Priority < 0)
  97                PFPriority[F->ID] =  I->Priority;
  98             else
  99                PFPriority[F->ID] = Cur;
 100
 101             if (PFPriority[F->ID] > 1000)
 102                StatusOverride = true;
 103
 104             Fixed[F->ID] = true;
 105          }
 106       }
 107    }
 108
 109    if (_config->FindB("Debug::pkgPolicy",false) == true)
 110       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 111          cout << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << endl;
 112
 113    return true;
 114 }
 115                                                                         /*}}}*/
 116 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 117 // ---------------------------------------------------------------------
 118 /* Evaluate the package pins and the default list to deteremine what the
 119    best package is. */
 120 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator Pkg)
 121 {
 122    // Look for a package pin and evaluate it.
 123    signed Max = GetPriority(Pkg);
 124    pkgCache::VerIterator Pref = GetMatch(Pkg);
 125
 126    // no package = no candidate version
 127    if (Pkg.end() == true)
 128       return Pref;
 129
 130    // packages with a pin lower than 0 have no newer candidate than the current version
 131    if (Max < 0)
 132       return Pkg.CurrentVer();
 133
 134    /* Falling through to the default version.. Setting Max to zero
 135       effectively excludes everything <= 0 which are the non-automatic
 136       priorities.. The status file is given a prio of 100 which will exclude
 137       not-automatic sources, except in a single shot not-installed mode.
 138       The second pseduo-status file is at prio 1000, above which will permit
 139       the user to force-downgrade things.
 140
 141       The user pin is subject to the same priority rules as default
 142       selections. Thus there are two ways to create a pin - a pin that
 143       tracks the default when the default is taken away, and a permanent
 144       pin that stays at that setting.
 145     */
 146    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 147    {
 148       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 149       {
 150          /* If this is the status file, and the current version is not the
 151             version in the status file (ie it is not installed, or somesuch)
 152             then it is not a candidate for installation, ever. This weeds
 153             out bogus entries that may be due to config-file states, or
 154             other. */
 155          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 156              Pkg.CurrentVer() != Ver)
 157             continue;
 158
 159          signed Prio = PFPriority[VF.File()->ID];
 160          if (Prio > Max)
 161          {
 162             Pref = Ver;
 163             Max = Prio;
 164          }
 165       }
 166
 167       if (Pkg.CurrentVer() == Ver && Max < 1000)
 168       {
 169          /* Elevate our current selection (or the status file itself)
 170             to the Pseudo-status priority. */
 171          if (Pref.end() == true)
 172             Pref = Ver;
 173          Max = 1000;
 174
 175          // Fast path optimize.
 176          if (StatusOverride == false)
 177             break;
 178       }
 179    }
 180    return Pref;
 181 }
 182                                                                         /*}}}*/
 183 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 184 // ---------------------------------------------------------------------
 185 /* For performance we have 3 tables, the default table, the main cache
 186    table (hashed to the cache). A blank package name indicates the pin
 187    belongs to the default table. Order of insertion matters here, the
 188    earlier defaults override later ones. */
 189 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 190                           string Data,signed short Priority)
 191 {
 192    Pin *P = 0;
 193
 194    if (Name.empty() == true)
 195       P = &*Defaults.insert(Defaults.end(),PkgPin());
 196    else
 197    {
 198       // Get a spot to put the pin
 199       pkgCache::PkgIterator Pkg = Cache->FindPkg(Name);
 200       if (Pkg.end() == true)
 201       {
 202          // Check the unmatched table
 203          for (vector<PkgPin>::iterator I = Unmatched.begin();
 204               I != Unmatched.end() && P == 0; I++)
 205             if (I->Pkg == Name)
 206                P = &*I;
 207
 208          if (P == 0)
 209             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 210       }
 211       else
 212       {
 213          P = Pins + Pkg->ID;
 214       }
 215    }
 216
 217    // Set..
 218    P->Type = Type;
 219    P->Priority = Priority;
 220    P->Data = Data;
 221 }
 222                                                                         /*}}}*/
 223 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 224 // ---------------------------------------------------------------------
 225 /* */
 226 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator Pkg)
 227 {
 228    const Pin &PPkg = Pins[Pkg->ID];
 229    if (PPkg.Type != pkgVersionMatch::None)
 230    {
 231       pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 232       return Match.Find(Pkg);
 233    }
 234    return pkgCache::VerIterator(*Pkg.Cache());
 235 }
 236                                                                         /*}}}*/
 237 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 238 // ---------------------------------------------------------------------
 239 /* */
 240 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 241 {
 242    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 243    {
 244       // In this case 0 means default priority
 245       if (Pins[Pkg->ID].Priority == 0)
 246          return 989;
 247       return Pins[Pkg->ID].Priority;
 248    }
 249
 250    return 0;
 251 }
 252                                                                         /*}}}*/
 253 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 254 // ---------------------------------------------------------------------
 255 /* The preference file is a user generated file so the parser should
 256    therefore be a bit more friendly by allowing comments and new lines
 257    all over the place rather than forcing a special format */
 258 class PreferenceSection : public pkgTagSection
 259 {
 260    void TrimRecord(bool BeforeRecord, const char* &End)
 261    {
 262       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 263          if (Stop[0] == '#')
 264             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 265    }
 266 };
 267                                                                         /*}}}*/
 268 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 269 // ---------------------------------------------------------------------
 270 /* */
 271 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 272 {
 273    if (Dir.empty() == true)
 274       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 275
 276    DIR *D = opendir(Dir.c_str());
 277    if (D == 0)
 278       return _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
 279
 280    vector<string> List;
 281
 282    for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D))
 283    {
 284       if (Ent->d_name[0] == '.')
 285          continue;
 286
 287       // Skip bad file names ala run-parts
 288       const char *C = Ent->d_name;
 289       for (; *C != 0; C++)
 290          if (isalpha(*C) == 0 && isdigit(*C) == 0 && *C != '_' && *C != '-')
 291             break;
 292       if (*C != 0)
 293          continue;
 294
 295       // Make sure it is a file and not something else
 296       string File = flCombine(Dir,Ent->d_name);
 297       struct stat St;
 298       if (stat(File.c_str(),&St) != 0 || S_ISREG(St.st_mode) == 0)
 299          continue;
 300
 301       List.push_back(File);
 302    }
 303    closedir(D);
 304
 305    sort(List.begin(),List.end());
 306
 307    // Read the files
 308    for (vector<string>::const_iterator I = List.begin(); I != List.end(); I++)
 309       if (ReadPinFile(Plcy, *I) == false)
 310          return false;
 311    return true;
 312 }
 313                                                                         /*}}}*/
 314 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 315 // ---------------------------------------------------------------------
 316 /* I'd like to see the preferences file store more than just pin information
 317    but right now that is the only stuff I have to store. Later there will
 318    have to be some kind of combined super parser to get the data into all
 319    the right classes.. */
 320 bool ReadPinFile(pkgPolicy &Plcy,string File)
 321 {
 322    if (File.empty() == true)
 323       File = _config->FindFile("Dir::Etc::Preferences");
 324
 325    if (FileExists(File) == false)
 326       return true;
 327
 328    FileFd Fd(File,FileFd::ReadOnly);
 329    pkgTagFile TF(&Fd);
 330    if (_error->PendingError() == true)
 331       return false;
 332
 333    PreferenceSection Tags;
 334    while (TF.Step(Tags) == true)
 335    {
 336       string Name = Tags.FindS("Package");
 337       if (Name.empty() == true)
 338          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 339       if (Name == "*")
 340          Name = string();
 341
 342       const char *Start;
 343       const char *End;
 344       if (Tags.Find("Pin",Start,End) == false)
 345          continue;
 346
 347       const char *Word = Start;
 348       for (; Word != End && isspace(*Word) == 0; Word++);
 349
 350       // Parse the type..
 351       pkgVersionMatch::MatchType Type;
 352       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 353          Type = pkgVersionMatch::Version;
 354       else if (stringcasecmp(Start,Word,"release") == 0)
 355          Type = pkgVersionMatch::Release;
 356       else if (stringcasecmp(Start,Word,"origin") == 0)
 357          Type = pkgVersionMatch::Origin;
 358       else
 359       {
 360          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 361          continue;
 362       }
 363       for (; Word != End && isspace(*Word) != 0; Word++);
 364
 365       short int priority = Tags.FindI("Pin-Priority", 0);
 366       if (priority == 0)
 367       {
 368          _error->Warning(_("No priority (or zero) specified for pin"));
 369          continue;
 370       }
 371
 372       istringstream s(Name);
 373       string pkg;
 374       while(!s.eof())
 375       {
 376          s >> pkg;
 377          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 378       };
 379    }
 380
 381    Plcy.InitDefaults();
 382    return true;
 383 }
 384                                                                         /*}}}*/