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apt/apt-pkg/policy.cc
Daniel Baumann 6810ba718b
Adding upstream version 3.0.2. 
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-20 21:10:43 +02:00

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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/strutl.h>
#include <apt-pkg/tagfile-keys.h>
#include <apt-pkg/tagfile.h>
#include <apt-pkg/version.h>
#include <apt-pkg/versionmatch.h>
#include <cctype>
#include <cstddef>
#include <cstring>
#include <iostream>
#include <random>
#include <sstream>
#include <string>
#include <vector>
#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 = std::make_unique<signed short[]>(Owner->Head().PackageFileCount);
VerPins = std::make_unique<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 = {};
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,"source-version") == 0 && Name.empty() == false)
Type = pkgVersionMatch::SourceVersion;
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(std::string{Name}); // TODO: replace with std::string_view_stream in C++23
string pkg;
while(!s.eof())
{
s >> pkg;
Plcy.CreatePin(Type, pkg, string(Word,End),priority);
};
}
Plcy.InitDefaults();
return true;
}
/*}}}*/
pkgPolicy::~pkgPolicy() = default;
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