File: policy.cc

package info (click to toggle)
apt 1.8.2
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 19,680 kB
  • sloc: cpp: 67,708; sh: 24,865; xml: 5,187; perl: 577; ansic: 190; makefile: 28; python: 28
file content (442 lines) | stat: -rw-r--r-- 15,382 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
/* ######################################################################

   Package Version Policy implementation

   This is just a really simple wrapper around pkgVersionMatch with
   some added goodies to manage the list of things..

   See man apt_preferences for what value means what.

   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#include <config.h>

#include <apt-pkg/cachefilter.h>
#include <apt-pkg/configuration.h>
#include <apt-pkg/error.h>
#include <apt-pkg/fileutl.h>
#include <apt-pkg/netrc.h>
#include <apt-pkg/pkgcache.h>
#include <apt-pkg/policy.h>
#include <apt-pkg/strutl.h>
#include <apt-pkg/tagfile.h>
#include <apt-pkg/version.h>
#include <apt-pkg/versionmatch.h>

#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <ctype.h>
#include <stddef.h>
#include <string.h>

#include <apti18n.h>
									/*}}}*/

using namespace std;

constexpr short NEVER_PIN = std::numeric_limits<short>::min();

// Policy::Init - Startup and bind to a cache				/*{{{*/
// ---------------------------------------------------------------------
/* Set the defaults for operation. The default mode with no loaded policy
   file matches the V0 policy engine. */
pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(nullptr), VerPins(nullptr),
   PFPriority(nullptr), Cache(Owner), d(NULL)
{
   if (Owner == 0)
      return;
   PFPriority = new signed short[Owner->Head().PackageFileCount];
   auto PackageCount = Owner->Head().PackageCount;
   Pins = new Pin[PackageCount];
   VerPins = new Pin[Owner->Head().VersionCount];

   for (decltype(PackageCount) I = 0; I != PackageCount; ++I)
      Pins[I].Type = pkgVersionMatch::None;
   auto VersionCount = Owner->Head().VersionCount;
   for (decltype(VersionCount) I = 0; I != VersionCount; ++I)
      VerPins[I].Type = pkgVersionMatch::None;

   // The config file has a master override.
   string DefRel = _config->Find("APT::Default-Release");
   if (DefRel.empty() == false)
   {
      bool found = false;
      // FIXME: make ExpressionMatches static to use it here easily
      pkgVersionMatch vm("", pkgVersionMatch::None);
      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
      {
	 if (vm.ExpressionMatches(DefRel, F.Archive()) ||
	     vm.ExpressionMatches(DefRel, F.Codename()) ||
	     vm.ExpressionMatches(DefRel, F.Version()) ||
	     (DefRel.length() > 2 && DefRel[1] == '='))
	    found = true;
      }
      if (found == false)
	 _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
      else
	 CreatePin(pkgVersionMatch::Release,"",DefRel,990);
   }
   InitDefaults();
}
									/*}}}*/
// Policy::InitDefaults - Compute the default selections		/*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgPolicy::InitDefaults()
{
   std::vector<std::unique_ptr<FileFd>> authconfs;
   // Initialize the priorities based on the status of the package file
   for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
   {
      PFPriority[I->ID] = 500;
      if (I.Flagged(pkgCache::Flag::NotSource))
	 PFPriority[I->ID] = 100;
      else if (I.Flagged(pkgCache::Flag::ButAutomaticUpgrades))
	 PFPriority[I->ID] = 100;
      else if (I.Flagged(pkgCache::Flag::NotAutomatic))
	 PFPriority[I->ID] = 1;
      if (I.Flagged(pkgCache::Flag::PackagesRequireAuthorization) && !IsAuthorized(I, authconfs))
	 PFPriority[I->ID] = NEVER_PIN;
   }

   // Apply the defaults..
   std::unique_ptr<bool[]> Fixed(new bool[Cache->HeaderP->PackageFileCount]);
   memset(Fixed.get(),0,sizeof(Fixed[0])*Cache->HeaderP->PackageFileCount);
   StatusOverride = false;
   for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
   {
      pkgVersionMatch Match(I->Data,I->Type);
      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
      {
	 if ((Fixed[F->ID] == false || I->Priority == NEVER_PIN) && PFPriority[F->ID] != NEVER_PIN && Match.FileMatch(F) == true)
	 {
	    PFPriority[F->ID] = I->Priority;

	    if (PFPriority[F->ID] >= 1000)
	       StatusOverride = true;

	    Fixed[F->ID] = true;
	 }
      }
   }

   if (_config->FindB("Debug::pkgPolicy",false) == true)
      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
	 std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;

   return true;
}
									/*}}}*/
// Policy::GetCandidateVer - Get the candidate install version		/*{{{*/
// ---------------------------------------------------------------------
/* Evaluate the package pins and the default list to deteremine what the
   best package is. */
pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
{
   pkgCache::VerIterator cand;
   pkgCache::VerIterator cur = Pkg.CurrentVer();
   int candPriority = -1;
   pkgVersioningSystem *vs = Cache->VS;

   for (pkgCache::VerIterator ver = Pkg.VersionList(); ver.end() == false; ++ver) {
      int priority = GetPriority(ver, true);

      if (priority == 0 || priority <= candPriority)
	 continue;

      // TODO: Maybe optimize to not compare versions
      if (!cur.end() && priority < 1000
	  && (vs->CmpVersion(ver.VerStr(), cur.VerStr()) < 0))
	 continue;

      candPriority = priority;
      cand = ver;
   }

   return cand;
}
									/*}}}*/
// Policy::CreatePin - Create an entry in the pin table..		/*{{{*/
// ---------------------------------------------------------------------
/* For performance we have 3 tables, the default table, the main cache
   table (hashed to the cache). A blank package name indicates the pin
   belongs to the default table. Order of insertion matters here, the
   earlier defaults override later ones. */
void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
			  string Data,signed short Priority)
{
   if (Name.empty() == true)
   {
      Pin *P = &*Defaults.insert(Defaults.end(),Pin());
      P->Type = Type;
      P->Priority = Priority;
      P->Data = Data;
      return;
   }

   size_t found = Name.rfind(':');
   string Arch;
   if (found != string::npos) {
      Arch = Name.substr(found+1);
      Name.erase(found);
   }

   // Allow pinning by wildcards - beware of package names looking like wildcards!
   // TODO: Maybe we should always prefer specific pins over non-specific ones.
   if ((Name[0] == '/' && Name[Name.length() - 1] == '/') || Name.find_first_of("*[?") != string::npos)
   {
      pkgVersionMatch match(Data, Type);
      for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
	 if (Name != G.Name() && match.ExpressionMatches(Name, G.Name()))
	 {
	    if (Arch.empty() == false)
	       CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
	    else
	       CreatePin(Type, G.Name(), Data, Priority);
	 }
      return;
   }

   // find the package (group) this pin applies to
   pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
   bool matched = false;
   if (Grp.end() == false)
   {
      std::string MatchingArch;
      if (Arch.empty() == true)
	 MatchingArch = Cache->NativeArch();
      else
	 MatchingArch = Arch;
      APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
      for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
      {
	 if (pams(Pkg.Arch()) == false)
	    continue;
	 Pin *P = Pins + Pkg->ID;
	 // the first specific stanza for a package is the ruler,
	 // all others need to be ignored
	 if (P->Type != pkgVersionMatch::None)
	    P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
	 P->Type = Type;
	 P->Priority = Priority;
	 P->Data = Data;
	 matched = true;

	 // Find matching version(s) and copy the pin into it
	 pkgVersionMatch Match(P->Data,P->Type);
	 for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() != true; ++Ver)
	 {
	    if (Match.VersionMatches(Ver)) {
	       Pin *VP = VerPins + Ver->ID;
	       if (VP->Type == pkgVersionMatch::None)
		  *VP = *P;
	    }
	 }
      }
   }

   if (matched == false)
   {
      PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
      if (Arch.empty() == false)
	 P->Pkg.append(":").append(Arch);
      P->Type = Type;
      P->Priority = Priority;
      P->Data = Data;
      return;
   }
}
									/*}}}*/
// Policy::GetMatch - Get the matching version for a package pin	/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
{
   const Pin &PPkg = Pins[Pkg->ID];
   if (PPkg.Type == pkgVersionMatch::None)
      return pkgCache::VerIterator(*Pkg.Cache());

   pkgVersionMatch Match(PPkg.Data,PPkg.Type);
   return Match.Find(Pkg);
}
									/*}}}*/
// Policy::GetPriority - Get the priority of the package pin		/*{{{*/
// ---------------------------------------------------------------------
/* */
APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
{
   if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
      return Pins[Pkg->ID].Priority;
   return 0;
}
APT_PURE signed short pkgPolicy::GetPriority(pkgCache::VerIterator const &Ver, bool ConsiderFiles)
{
   if (VerPins[Ver->ID].Type != pkgVersionMatch::None)
   {
      // If all sources are never pins, the never pin wins.
      if (VerPins[Ver->ID].Priority == NEVER_PIN)
	 return NEVER_PIN;
      for (pkgCache::VerFileIterator file = Ver.FileList(); file.end() == false; file++)
	 if (GetPriority(file.File()) != NEVER_PIN)
	    return VerPins[Ver->ID].Priority;
   }
   if (!ConsiderFiles)
      return 0;

   // priorities are short ints, but we want to pick a value outside the valid range here
   auto priority = std::numeric_limits<signed int>::min();
   for (pkgCache::VerFileIterator file = Ver.FileList(); file.end() == false; file++)
   {
      /* If this is the status file, and the current version is not the
         version in the status file (ie it is not installed, or somesuch)
         then it is not a candidate for installation, ever. This weeds
         out bogus entries that may be due to config-file states, or
         other. */
      if (file.File().Flagged(pkgCache::Flag::NotSource) && Ver.ParentPkg().CurrentVer() != Ver)
	 priority = std::max(priority, static_cast<decltype(priority)>(-1));
      else
	 priority = std::max(priority, static_cast<decltype(priority)>(GetPriority(file.File())));
   }

   return priority == std::numeric_limits<decltype(priority)>::min() ? 0 : priority;
}
APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
{
   return PFPriority[File->ID];
}
									/*}}}*/
// ReadPinDir - Load the pin files from this dir into a Policy		/*{{{*/
// ---------------------------------------------------------------------
/* This will load each pin file in the given dir into a Policy. If the
   given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
   Note also that this method will issue a warning if the dir does not
   exists but it will return true in this case! */
bool ReadPinDir(pkgPolicy &Plcy,string Dir)
{
   if (Dir.empty() == true)
      Dir = _config->FindDir("Dir::Etc::PreferencesParts", "/dev/null");

   if (DirectoryExists(Dir) == false)
   {
      if (APT::String::Endswith(Dir, "/dev/null") == false)
	 _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
      return true;
   }

   _error->PushToStack();
   vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
   bool const PendingErrors = _error->PendingError();
   _error->MergeWithStack();
   if (PendingErrors)
      return false;

   // Read the files
   bool good = true;
   for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
      good = ReadPinFile(Plcy, *I) && good;
   return good;
}
									/*}}}*/
// ReadPinFile - Load the pin file into a Policy			/*{{{*/
// ---------------------------------------------------------------------
/* I'd like to see the preferences file store more than just pin information
   but right now that is the only stuff I have to store. Later there will
   have to be some kind of combined super parser to get the data into all
   the right classes.. */
bool ReadPinFile(pkgPolicy &Plcy,string File)
{
   if (File.empty() == true)
      File = _config->FindFile("Dir::Etc::Preferences");

   if (RealFileExists(File) == false)
      return true;

   FileFd Fd;
   if (OpenConfigurationFileFd(File, Fd) == false)
      return false;

   pkgTagFile TF(&Fd, pkgTagFile::SUPPORT_COMMENTS);
   if (Fd.IsOpen() == false || Fd.Failed())
      return false;

   pkgTagSection Tags;
   while (TF.Step(Tags) == true)
   {
      // can happen when there are only comments in a record
      if (Tags.Count() == 0)
         continue;

      string Name = Tags.FindS("Package");
      if (Name.empty() == true)
	 return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
      if (Name == "*")
	 Name = string();
      
      const char *Start;
      const char *End;
      if (Tags.Find("Pin",Start,End) == false)
	 continue;
	 
      const char *Word = Start;
      for (; Word != End && isspace(*Word) == 0; Word++);

      // Parse the type..
      pkgVersionMatch::MatchType Type;
      if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
	 Type = pkgVersionMatch::Version;
      else if (stringcasecmp(Start,Word,"release") == 0)
	 Type = pkgVersionMatch::Release;
      else if (stringcasecmp(Start,Word,"origin") == 0)
	 Type = pkgVersionMatch::Origin;
      else
      {
	 _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
	 continue;
      }
      for (; Word != End && isspace(*Word) != 0; Word++);

      _error->PushToStack();
      std::string sPriority = Tags.FindS("Pin-Priority");
      int priority = sPriority == "never" ? NEVER_PIN : Tags.FindI("Pin-Priority", 0);
      bool const newError = _error->PendingError();
      _error->MergeWithStack();

      if (sPriority == "never" && not Name.empty())
	 return _error->Error(_("%s: The special 'Pin-Priority: %s' can only be used for 'Package: *' records"), File.c_str(), "never");

      // Silently clamp the never pin to never pin + 1
      if (priority == NEVER_PIN && sPriority != "never")
	 priority = NEVER_PIN + 1;
      if (priority < std::numeric_limits<short>::min() ||
          priority > std::numeric_limits<short>::max() ||
	  newError) {
	 return _error->Error(_("%s: Value %s is outside the range of valid pin priorities (%d to %d)"),
			      File.c_str(), Tags.FindS("Pin-Priority").c_str(),
			      std::numeric_limits<short>::min(),
			      std::numeric_limits<short>::max());
      }
      if (priority == 0)
      {
         return _error->Error(_("No priority (or zero) specified for pin"));
      }

      istringstream s(Name);
      string pkg;
      while(!s.eof())
      {
	 s >> pkg;
         Plcy.CreatePin(Type, pkg, string(Word,End),priority);
      };
   }

   Plcy.InitDefaults();
   return true;
}
									/*}}}*/

pkgPolicy::~pkgPolicy() {delete [] PFPriority; delete [] Pins; delete [] VerPins; }