lix/src/libstore/local-store.hh
Andrew Brooks 84fe75a12a Keep created temp dirs inside store, but protect from GC
Implements the approach suggested by feedback on PR #6994, where
tempdir paths are created in the store (now with an exclusive lock).

As part of this work, the currently-broken and unused
`createTempDirInStore` function is updated to create an exclusive lock
on the temp directory in the store.

The GC now makes a non-blocking attempt to lock any store directories
that "look like" the temp directories created by this function, and if
it can't acquire one, ignores the directory.
2022-09-06 17:48:00 -05:00

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#pragma once
#include "sqlite.hh"
#include "pathlocks.hh"
#include "store-api.hh"
#include "local-fs-store.hh"
#include "gc-store.hh"
#include "sync.hh"
#include "util.hh"
#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;
uint64_t bytesFreed = 0;
uint64_t blocksFreed = 0;
};
struct LocalStoreConfig : virtual LocalFSStoreConfig
{
using LocalFSStoreConfig::LocalFSStoreConfig;
Setting<bool> requireSigs{(StoreConfig*) this,
settings.requireSigs,
"require-sigs", "whether store paths should have a trusted signature on import"};
const std::string name() override { return "Local Store"; }
};
class LocalStore : public virtual LocalStoreConfig, public virtual LocalFSStore, 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 global GC lock */
AutoCloseFD fdGCLock;
/* The file to which we write our temporary roots. */
AutoCloseFD fdTempRoots;
/* Connection to the garbage collector. */
AutoCloseFD fdRootsSocket;
/* 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();
std::unique_ptr<PublicKeys> publicKeys;
};
Sync<State> _state;
public:
const Path dbDir;
const Path linksDir;
const Path reservedPath;
const Path schemaPath;
const Path tempRootsDir;
const Path fnTempRoots;
private:
const PublicKeys & getPublicKeys();
public:
// Hack for build-remote.cc.
PathSet locksHeld;
/* Initialise the local store, upgrading the schema if
necessary. */
LocalStore(const Params & params);
~LocalStore();
/* 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>> queryPartialDerivationOutputMap(const StorePath & path) override;
std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override;
StorePathSet querySubstitutablePaths(const StorePathSet & paths) override;
void querySubstitutablePathInfos(const StorePathCAMap & paths,
SubstitutablePathInfos & infos) 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;
void addIndirectRoot(const Path & path) override;
private:
void findTempRoots(Roots & roots, bool censor);
AutoCloseFD openGCLock();
public:
Roots findRoots(bool censor) override;
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);
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;
void vacuumDB();
void repairPath(const StorePath & path) override;
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:
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);
/* Delete a path from the Nix store. */
void invalidatePathChecked(const StorePath & path);
void verifyPath(const Path & path, const StringSet & store,
PathSet & 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);
void upgradeStore6();
void upgradeStore7();
PathSet queryValidPathsOld();
ValidPathInfo queryPathInfoOld(const Path & path);
void findRoots(const Path & path, unsigned char type, Roots & roots);
void findRootsNoTemp(Roots & roots, bool censor);
void findRuntimeRoots(Roots & roots, bool censor);
std::pair<Path, AutoCloseFD> createTempDirInStore();
void checkDerivationOutputs(const StorePath & drvPath, const Derivation & drv);
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 &);
void createUser(const std::string & userName, uid_t userId) override;
// XXX: Make a generic `Store` method
FixedOutputHash hashCAPath(
const FileIngestionMethod & method,
const HashType & hashType,
const StorePath & path);
FixedOutputHash hashCAPath(
const FileIngestionMethod & 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;
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. */
void canonicalisePathMetaData(const Path & path, uid_t fromUid, InodesSeen & inodesSeen);
void canonicalisePathMetaData(const Path & path, uid_t fromUid);
void canonicaliseTimestampAndPermissions(const Path & path);
MakeError(PathInUse, Error);
}