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+ // -*- 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/aptconfiguration.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/policy.h>
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+#include <apt-pkg/version.h>
+#include <apt-pkg/versionmatch.h>
+
+#include <iostream>
+#include <random>
+#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();
+
+struct pkgPolicy::Private
+{
+ std::string machineID;
+};
+
+// 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) : VerPins(nullptr),
+ PFPriority(nullptr), Cache(Owner), d(new Private)
+{
+ if (Owner == 0)
+ return;
+ PFPriority = new signed short[Owner->Head().PackageFileCount];
+ VerPins = new Pin[Owner->Head().VersionCount];
+
+ 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;
+ for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
+ {
+ if (pkgVersionMatch::ExpressionMatches(DefRel, F.Archive()) ||
+ pkgVersionMatch::ExpressionMatches(DefRel, F.Codename()) ||
+ pkgVersionMatch::ExpressionMatches(DefRel, F.Version()) ||
+ (DefRel.length() > 2 && DefRel[1] == '='))
+ found = true;
+ }
+ // "now" is our internal archive name for the status file,
+ // which we should accept even if we have no status file at the moment
+ if (not found && pkgVersionMatch::ExpressionMatches(DefRel, "now"))
+ found = true;
+ if (not found)
+ _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();
+
+ d->machineID = APT::Configuration::getMachineID();
+}
+ /*}}}*/
+// Policy::InitDefaults - Compute the default selections /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgPolicy::InitDefaults()
+{
+ // 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;
+ }
+
+ // 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 determine 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;
+ }
+
+ bool IsSourcePin = APT::String::Startswith(Name, "src:");
+ if (IsSourcePin) {
+ Name = Name.substr(sizeof("src:") - 1);
+ }
+
+ 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()))
+ {
+ auto NameToPinFor = IsSourcePin ? string("src:").append(G.Name()) : string(G.Name());
+ if (Arch.empty() == false)
+ CreatePin(Type, NameToPinFor.append(":").append(Arch), Data, Priority);
+ else
+ CreatePin(Type, NameToPinFor, 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);
+
+ if (IsSourcePin) {
+ for (pkgCache::VerIterator Ver = Grp.VersionsInSource(); not Ver.end(); Ver = Ver.NextInSource())
+ {
+ if (pams(Ver.ParentPkg().Arch()) == false)
+ continue;
+
+ PkgPin P(Ver.ParentPkg().FullName());
+ P.Type = Type;
+ P.Priority = Priority;
+ P.Data = Data;
+ // Find matching version(s) and copy the pin into it
+ pkgVersionMatch Match(P.Data,P.Type);
+ if (Match.VersionMatches(Ver)) {
+ Pin *VP = VerPins + Ver->ID;
+ if (VP->Type == pkgVersionMatch::None) {
+ *VP = P;
+ matched = true;
+ }
+ }
+ }
+ } else {
+ for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
+ {
+ if (pams(Pkg.Arch()) == false)
+ continue;
+
+ PkgPin P(Pkg.FullName());
+ P.Type = Type;
+ P.Priority = Priority;
+ P.Data = Data;
+
+ // 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;
+ matched = true;
+ }
+ }
+ }
+ }
+ }
+ }
+
+ 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::GetPriority - Get the priority of the package pin /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+// Returns true if this update is excluded by phasing.
+static inline bool ExcludePhased(std::string machineID, pkgCache::VerIterator const &Ver)
+{
+ if (Ver.PhasedUpdatePercentage() == 100)
+ return false;
+
+ // FIXME: We have migrated to a legacy implementation until LP: #1929082 is fixed
+ if (not _config->FindB("APT::Get::Phase-Policy", false))
+ return false;
+
+ // The order and fallbacks for the always/never checks come from update-manager and exist
+ // to preserve compatibility.
+ if (_config->FindB("APT::Get::Always-Include-Phased-Updates",
+ _config->FindB("Update-Manager::Always-Include-Phased-Updates", false)))
+ return false;
+
+ if (_config->FindB("APT::Get::Never-Include-Phased-Updates",
+ _config->FindB("Update-Manager::Never-Include-Phased-Updates", false)))
+ return true;
+
+ if (machineID.empty() // no machine-id
+ || getenv("SOURCE_DATE_EPOCH") != nullptr // reproducible build - always include
+ || APT::Configuration::isChroot())
+ return false;
+
+ std::string seedStr = std::string(Ver.SourcePkgName()) + "-" + Ver.SourceVerStr() + "-" + machineID;
+ std::seed_seq seed(seedStr.begin(), seedStr.end());
+ std::minstd_rand rand(seed);
+ std::uniform_int_distribution<unsigned int> dist(0, 100);
+
+ return dist(rand) > Ver.PhasedUpdatePercentage();
+}
+APT_PURE signed short pkgPolicy::GetPriority(pkgCache::VerIterator const &Ver, bool ConsiderFiles)
+{
+ auto ceiling = std::numeric_limits<signed int>::max();
+ if (ExcludePhased(d->machineID, Ver))
+ ceiling = 1;
+ 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 std::min((int)VerPins[Ver->ID].Priority, ceiling);
+ }
+ if (!ConsiderFiles)
+ return std::min(0, ceiling);
+
+ // 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<decltype(priority)>(priority, -1);
+ else
+ priority = std::max<decltype(priority)>(priority, GetPriority(file.File()));
+ }
+
+ return std::min(priority == std::numeric_limits<decltype(priority)>::min() ? 0 : priority, ceiling);
+}
+APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
+{
+ return PFPriority[File->ID];
+}
+ /*}}}*/
+// SetPriority - Directly set priority /*{{{*/
+// ---------------------------------------------------------------------
+void pkgPolicy::SetPriority(pkgCache::VerIterator const &Ver, signed short Priority)
+{
+ Pin pin;
+ pin.Data = "pkgPolicy::SetPriority";
+ pin.Priority = Priority;
+ VerPins[Ver->ID] = pin;
+}
+void pkgPolicy::SetPriority(pkgCache::PkgFileIterator const &File, signed short Priority)
+{
+ PFPriority[File->ID] = Priority;
+}
+
+ /*}}}*/
+// 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;
+
+ auto Name = Tags.Find(pkgTagSection::Key::Package);
+ if (Name.empty())
+ return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
+ if (Name == "*")
+ Name = APT::StringView{};
+
+ 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"));
+ }
+
+ std::istringstream s(Name.to_string());
+ string pkg;
+ while(!s.eof())
+ {
+ s >> pkg;
+ Plcy.CreatePin(Type, pkg, string(Word,End),priority);
+ };
+ }
+
+ Plcy.InitDefaults();
+ return true;
+}
+ /*}}}*/
+
+pkgPolicy::~pkgPolicy()
+{
+ delete[] PFPriority;
+ delete[] VerPins;
+ delete d;
+}
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