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