lix/src/libstore/local-store.hh

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#pragma once
///@file
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#include "sqlite.hh"
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#include "pathlocks.hh"
#include "store-api.hh"
#include "indirect-root-store.hh"
#include "sync.hh"
#include "util.hh"
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#include <chrono>
#include <future>
#include <string>
#include <unordered_set>
namespace nix {
/**
* Nix store and database schema version.
*
* Version 1 (or 0) was Nix <=
* 0.7. Version 2 was Nix 0.8 and 0.9. Version 3 is Nix 0.10.
* Version 4 is Nix 0.11. Version 5 is Nix 0.12-0.16. Version 6 is
* Nix 1.0. Version 7 is Nix 1.3. Version 10 is 2.0.
*/
const int nixSchemaVersion = 10;
struct OptimiseStats
{
unsigned long filesLinked = 0;
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uint64_t bytesFreed = 0;
uint64_t blocksFreed = 0;
};
struct LocalStoreConfig : virtual LocalFSStoreConfig
{
using LocalFSStoreConfig::LocalFSStoreConfig;
Setting<bool> requireSigs{this,
settings.requireSigs,
"require-sigs",
"Whether store paths copied into this store should have a trusted signature."};
Setting<bool> readOnly{this,
false,
"read-only",
R"(
Allow this store to be opened when its [database](@docroot@/glossary.md#gloss-nix-database) is on a read-only filesystem.
Normally Nix will attempt to open the store database in read-write mode, even for querying (when write access is not needed), causing it to fail if the database is on a read-only filesystem.
Enable read-only mode to disable locking and open the SQLite database with the [`immutable` parameter](https://www.sqlite.org/c3ref/open.html) set.
> **Warning**
> Do not use this unless the filesystem is read-only.
>
> Using it when the filesystem is writable can cause incorrect query results or corruption errors if the database is changed by another process.
> While the filesystem the database resides on might appear to be read-only, consider whether another user or system might have write access to it.
)"};
const std::string name() override { return "Local Store"; }
std::string doc() override;
};
class LocalStore : public virtual LocalStoreConfig
, public virtual IndirectRootStore
, public virtual GcStore
{
private:
/**
* Lock file used for upgrading.
*/
AutoCloseFD globalLock;
struct State
{
/**
* The SQLite database object.
*/
SQLite db;
struct Stmts;
std::unique_ptr<Stmts> stmts;
/**
* The last time we checked whether to do an auto-GC, or an
* auto-GC finished.
*/
std::chrono::time_point<std::chrono::steady_clock> lastGCCheck;
/**
* Whether auto-GC is running. If so, get gcFuture to wait for
* the GC to finish.
*/
bool gcRunning = false;
std::shared_future<void> gcFuture;
/**
* How much disk space was available after the previous
* auto-GC. If the current available disk space is below
* minFree but not much below availAfterGC, then there is no
* point in starting a new GC.
*/
uint64_t availAfterGC = std::numeric_limits<uint64_t>::max();
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std::unique_ptr<PublicKeys> publicKeys;
};
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Sync<State> _state;
public:
const Path dbDir;
const Path linksDir;
const Path reservedPath;
const Path schemaPath;
const Path tempRootsDir;
const Path fnTempRoots;
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private:
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const PublicKeys & getPublicKeys();
protected:
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/**
* Initialise the local store, upgrading the schema if
* necessary.
* Protected so that users don't accidentally create a LocalStore
* instead of a platform's subclass.
*/
LocalStore(const Params & params);
LocalStore(std::string scheme, std::string path, const Params & params);
public:
/**
* Hack for build-remote.cc.
*/
PathSet locksHeld;
virtual ~LocalStore();
static std::set<std::string> uriSchemes()
{ return {}; }
/**
* Create a LocalStore, possibly a platform-specific subclass
*/
static std::shared_ptr<LocalStore> makeLocalStore(const Params & params);
/**
* Implementations of abstract store API methods.
*/
std::string getUri() override;
bool isValidPathUncached(const StorePath & path) override;
StorePathSet queryValidPaths(const StorePathSet & paths,
SubstituteFlag maybeSubstitute = NoSubstitute) override;
StorePathSet queryAllValidPaths() override;
void queryPathInfoUncached(const StorePath & path,
Callback<std::shared_ptr<const ValidPathInfo>> callback) noexcept override;
void queryReferrers(const StorePath & path, StorePathSet & referrers) override;
StorePathSet queryValidDerivers(const StorePath & path) override;
std::map<std::string, std::optional<StorePath>> queryStaticPartialDerivationOutputMap(const StorePath & path) override;
std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override;
StorePathSet querySubstitutablePaths(const StorePathSet & paths) override;
bool pathInfoIsUntrusted(const ValidPathInfo &) override;
bool realisationIsUntrusted(const Realisation & ) override;
void addToStore(const ValidPathInfo & info, Source & source,
RepairFlag repair, CheckSigsFlag checkSigs) override;
StorePath addToStoreFromDump(Source & dump, std::string_view name,
FileIngestionMethod method, HashType hashAlgo, RepairFlag repair, const StorePathSet & references) override;
StorePath addTextToStore(
std::string_view name,
std::string_view s,
const StorePathSet & references,
RepairFlag repair) override;
void addTempRoot(const StorePath & path) override;
private:
void createTempRootsFile();
/**
* The file to which we write our temporary roots.
*/
Sync<AutoCloseFD> _fdTempRoots;
/**
* The global GC lock.
*/
Sync<AutoCloseFD> _fdGCLock;
/**
* Connection to the garbage collector.
*/
Sync<AutoCloseFD> _fdRootsSocket;
public:
/**
* Implementation of IndirectRootStore::addIndirectRoot().
*
* The weak reference merely is a symlink to `path' from
* /nix/var/nix/gcroots/auto/<hash of `path'>.
*/
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void addIndirectRoot(const Path & path) override;
private:
void findTempRoots(Roots & roots, bool censor);
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AutoCloseFD openGCLock();
public:
Roots findRoots(bool censor) override;
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void collectGarbage(const GCOptions & options, GCResults & results) override;
/**
* Optimise the disk space usage of the Nix store by hard-linking
* files with the same contents.
*/
void optimiseStore(OptimiseStats & stats);
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void optimiseStore() override;
/**
* Optimise a single store path. Optionally, test the encountered
* symlinks for corruption.
*/
void optimisePath(const Path & path, RepairFlag repair);
bool verifyStore(bool checkContents, RepairFlag repair) override;
/**
* Register the validity of a path, i.e., that `path` exists, that
* the paths referenced by it exists, and in the case of an output
* path of a derivation, that it has been produced by a successful
* execution of the derivation (or something equivalent). Also
* register the hash of the file system contents of the path. The
* hash must be a SHA-256 hash.
*/
void registerValidPath(const ValidPathInfo & info);
void registerValidPaths(const ValidPathInfos & infos);
unsigned int getProtocol() override;
std::optional<TrustedFlag> isTrustedClient() override;
void vacuumDB();
void addSignatures(const StorePath & storePath, const StringSet & sigs) override;
/**
* If free disk space in /nix/store if below minFree, delete
* garbage until it exceeds maxFree.
*/
void autoGC(bool sync = true);
/**
* Register the store path 'output' as the output named 'outputName' of
* derivation 'deriver'.
*/
void registerDrvOutput(const Realisation & info) override;
void registerDrvOutput(const Realisation & info, CheckSigsFlag checkSigs) override;
void cacheDrvOutputMapping(
State & state,
const uint64_t deriver,
const std::string & outputName,
const StorePath & output);
std::optional<const Realisation> queryRealisation_(State & state, const DrvOutput & id);
std::optional<std::pair<int64_t, Realisation>> queryRealisationCore_(State & state, const DrvOutput & id);
void queryRealisationUncached(const DrvOutput&,
Callback<std::shared_ptr<const Realisation>> callback) noexcept override;
std::optional<std::string> getVersion() override;
private:
/**
* Retrieve the current version of the database schema.
* If the database does not exist yet, the version returned will be 0.
*/
int getSchema();
void openDB(State & state, bool create);
void makeStoreWritable();
uint64_t queryValidPathId(State & state, const StorePath & path);
uint64_t addValidPath(State & state, const ValidPathInfo & info, bool checkOutputs = true);
void invalidatePath(State & state, const StorePath & path);
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/**
* Delete a path from the Nix store.
*/
void invalidatePathChecked(const StorePath & path);
void verifyPath(const StorePath & path, const StorePathSet & store,
StorePathSet & done, StorePathSet & validPaths, RepairFlag repair, bool & errors);
std::shared_ptr<const ValidPathInfo> queryPathInfoInternal(State & state, const StorePath & path);
void updatePathInfo(State & state, const ValidPathInfo & info);
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void upgradeStore6();
void upgradeStore7();
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PathSet queryValidPathsOld();
ValidPathInfo queryPathInfoOld(const Path & path);
void findRoots(const Path & path, unsigned char type, Roots & roots);
void findRootsNoTemp(Roots & roots, bool censor);
/**
* Find possible garbage collector roots in a platform-specific manner,
* e.g. by looking in `/proc` or using `lsof`
*/
virtual void findPlatformRoots(UncheckedRoots & unchecked);
void findRuntimeRoots(Roots & roots, bool censor);
std::pair<Path, AutoCloseFD> createTempDirInStore();
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typedef std::unordered_set<ino_t> InodeHash;
InodeHash loadInodeHash();
Strings readDirectoryIgnoringInodes(const Path & path, const InodeHash & inodeHash);
void optimisePath_(Activity * act, OptimiseStats & stats, const Path & path, InodeHash & inodeHash, RepairFlag repair);
// Internal versions that are not wrapped in retry_sqlite.
bool isValidPath_(State & state, const StorePath & path);
void queryReferrers(State & state, const StorePath & path, StorePathSet & referrers);
/**
* Add signatures to a ValidPathInfo or Realisation using the secret keys
* specified by the secret-key-files option.
*/
void signPathInfo(ValidPathInfo & info);
void signRealisation(Realisation &);
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// XXX: Make a generic `Store` method
ContentAddress hashCAPath(
const ContentAddressMethod & method,
const HashType & hashType,
const StorePath & path);
ContentAddress hashCAPath(
const ContentAddressMethod & method,
const HashType & hashType,
const Path & path,
const std::string_view pathHash
);
void addBuildLog(const StorePath & drvPath, std::string_view log) override;
friend struct LocalDerivationGoal;
friend struct PathSubstitutionGoal;
friend struct SubstitutionGoal;
friend struct DerivationGoal;
};
typedef std::pair<dev_t, ino_t> Inode;
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typedef std::set<Inode> InodesSeen;
/**
* "Fix", or canonicalise, the meta-data of the files in a store path
* after it has been built. In particular:
*
* - the last modification date on each file is set to 1 (i.e.,
* 00:00:01 1/1/1970 UTC)
*
* - the permissions are set of 444 or 555 (i.e., read-only with or
* without execute permission; setuid bits etc. are cleared)
*
* - the owner and group are set to the Nix user and group, if we're
* running as root.
*
* If uidRange is not empty, this function will throw an error if it
* encounters files owned by a user outside of the closed interval
* [uidRange->first, uidRange->second].
*/
void canonicalisePathMetaData(
const Path & path,
std::optional<std::pair<uid_t, uid_t>> uidRange,
InodesSeen & inodesSeen);
void canonicalisePathMetaData(
const Path & path,
std::optional<std::pair<uid_t, uid_t>> uidRange);
void canonicaliseTimestampAndPermissions(const Path & path);
MakeError(PathInUse, Error);
}