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-rw-r--r--third_party/nix/src/libstore/local-store.hh319
1 files changed, 319 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/local-store.hh b/third_party/nix/src/libstore/local-store.hh
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+++ b/third_party/nix/src/libstore/local-store.hh
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+#pragma once
+
+#include <chrono>
+#include <future>
+#include <string>
+#include <unordered_set>
+
+#include <absl/status/status.h>
+#include <absl/strings/str_split.h>
+
+#include "libstore/pathlocks.hh"
+#include "libstore/sqlite.hh"
+#include "libstore/store-api.hh"
+#include "libutil/sync.hh"
+#include "libutil/util.hh"
+
+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 Derivation;
+
+struct OptimiseStats {
+  unsigned long filesLinked = 0;
+  unsigned long long bytesFreed = 0;
+  unsigned long long blocksFreed = 0;
+};
+
+class LocalStore : public LocalFSStore {
+ private:
+  /* Lock file used for upgrading. */
+  AutoCloseFD globalLock;
+
+  struct State {
+    /* The SQLite database object. */
+    SQLite db;
+
+    /* Some precompiled SQLite statements. */
+    SQLiteStmt stmtRegisterValidPath;
+    SQLiteStmt stmtUpdatePathInfo;
+    SQLiteStmt stmtAddReference;
+    SQLiteStmt stmtQueryPathInfo;
+    SQLiteStmt stmtQueryReferences;
+    SQLiteStmt stmtQueryReferrers;
+    SQLiteStmt stmtInvalidatePath;
+    SQLiteStmt stmtAddDerivationOutput;
+    SQLiteStmt stmtQueryValidDerivers;
+    SQLiteStmt stmtQueryDerivationOutputs;
+    SQLiteStmt stmtQueryPathFromHashPart;
+    SQLiteStmt stmtQueryValidPaths;
+
+    /* The file to which we write our temporary roots. */
+    AutoCloseFD fdTempRoots;
+
+    /* 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, std::recursive_mutex> _state;
+
+ public:
+  PathSetting realStoreDir_;
+
+  const Path realStoreDir;
+  const Path dbDir;
+  const Path linksDir;
+  const Path reservedPath;
+  const Path schemaPath;
+  const Path trashDir;
+  const Path tempRootsDir;
+  const Path fnTempRoots;
+
+ private:
+  Setting<bool> requireSigs{
+      (Store*)this, settings.requireSigs, "require-sigs",
+      "whether store paths should have a trusted signature on import"};
+
+  const PublicKeys& getPublicKeys();
+
+ public:
+  // Hack for build-remote.cc.
+  // TODO(tazjin): remove this when we've got gRPC
+  PathSet locksHeld =
+      absl::StrSplit(getEnv("NIX_HELD_LOCKS").value_or(""),
+                     absl::ByAnyChar(" \t\n\r"), absl::SkipEmpty());
+
+  /* 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 Path& path) override;
+
+  PathSet queryValidPaths(const PathSet& paths, SubstituteFlag maybeSubstitute =
+                                                    NoSubstitute) override;
+
+  PathSet queryAllValidPaths() override;
+
+  void queryPathInfoUncached(
+      const Path& path,
+      Callback<std::shared_ptr<ValidPathInfo>> callback) noexcept override;
+
+  void queryReferrers(const Path& path, PathSet& referrers) override;
+
+  PathSet queryValidDerivers(const Path& path) override;
+
+  PathSet queryDerivationOutputs(const Path& path) override;
+
+  StringSet queryDerivationOutputNames(const Path& path) override;
+
+  Path queryPathFromHashPart(const std::string& hashPart) override;
+
+  PathSet querySubstitutablePaths(const PathSet& paths) override;
+
+  void querySubstitutablePathInfos(const PathSet& paths,
+                                   SubstitutablePathInfos& infos) override;
+
+  void addToStore(const ValidPathInfo& info, Source& source, RepairFlag repair,
+                  CheckSigsFlag checkSigs,
+                  std::shared_ptr<FSAccessor> accessor) override;
+
+  Path addToStore(const std::string& name, const Path& srcPath, bool recursive,
+                  HashType hashAlgo, PathFilter& filter,
+                  RepairFlag repair) override;
+
+  /* Like addToStore(), but the contents of the path are contained
+     in `dump', which is either a NAR serialisation (if recursive ==
+     true) or simply the contents of a regular file (if recursive ==
+     false). */
+  Path addToStoreFromDump(const std::string& dump, const std::string& name,
+                          bool recursive = true, HashType hashAlgo = htSHA256,
+                          RepairFlag repair = NoRepair);
+
+  Path addTextToStore(const std::string& name, const std::string& s,
+                      const PathSet& references, RepairFlag repair) override;
+
+  absl::Status buildPaths(std::ostream& log_sink, const PathSet& paths,
+                          BuildMode build_mode) override;
+
+  BuildResult buildDerivation(std::ostream& log_sink, const Path& drvPath,
+                              const BasicDerivation& drv,
+                              BuildMode buildMode) override;
+
+  void ensurePath(const Path& path) override;
+
+  void addTempRoot(const Path& path) override;
+
+  void addIndirectRoot(const Path& path) override;
+
+  void syncWithGC() override;
+
+ private:
+  typedef std::shared_ptr<AutoCloseFD> FDPtr;
+  using FDs = std::list<FDPtr>;
+
+  void findTempRoots(FDs& fds, Roots& roots, bool censor);
+
+ 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. */
+  void optimisePath(const Path& path);
+
+  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();
+
+  /* Repair the contents of the given path by redownloading it using
+     a substituter (if available). */
+  void repairPath(const Path& path);
+
+  void addSignatures(const Path& 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);
+
+ private:
+  int getSchema();
+
+  void openDB(State& state, bool create);
+
+  void makeStoreWritable();
+
+  static uint64_t queryValidPathId(State& state, const Path& path);
+
+  uint64_t addValidPath(State& state, const ValidPathInfo& info,
+                        bool checkOutputs = true);
+
+  void invalidatePath(State& state, const Path& path);
+
+  /* Delete a path from the Nix store. */
+  void invalidatePathChecked(const Path& path);
+
+  void verifyPath(const Path& path, const PathSet& store, PathSet& done,
+                  PathSet& validPaths, RepairFlag repair, bool& errors);
+
+  static void updatePathInfo(State& state, const ValidPathInfo& info);
+
+  void upgradeStore6();
+  void upgradeStore7();
+  PathSet queryValidPathsOld();
+  ValidPathInfo queryPathInfoOld(const Path& path);
+
+  struct GCState;
+
+  static void deleteGarbage(GCState& state, const Path& path);
+
+  void tryToDelete(GCState& state, const Path& path);
+
+  bool canReachRoot(GCState& state, PathSet& visited, const Path& path);
+
+  void deletePathRecursive(GCState& state, const Path& path);
+
+  static bool isActiveTempFile(const GCState& state, const Path& path,
+                               const std::string& suffix);
+
+  AutoCloseFD openGCLock(LockType lockType);
+
+  void findRoots(const Path& path, unsigned char type, Roots& roots);
+
+  void findRootsNoTemp(Roots& roots, bool censor);
+
+  void findRuntimeRoots(Roots& roots, bool censor);
+
+  void removeUnusedLinks(const GCState& state);
+
+  Path createTempDirInStore();
+
+  void checkDerivationOutputs(const Path& drvPath, const Derivation& drv);
+
+  using InodeHash = std::unordered_set<ino_t>;
+
+  InodeHash loadInodeHash();
+  static Strings readDirectoryIgnoringInodes(const Path& path,
+                                             const InodeHash& inodeHash);
+  void optimisePath_(OptimiseStats& stats, const Path& path,
+                     InodeHash& inodeHash);
+
+  // Internal versions that are not wrapped in retry_sqlite.
+  static bool isValidPath_(State& state, const Path& path);
+  static void queryReferrers(State& state, const Path& path,
+                             PathSet& referrers);
+
+  /* Add signatures to a ValidPathInfo using the secret keys
+     specified by the ‘secret-key-files’ option. */
+  static void signPathInfo(ValidPathInfo& info);
+
+  Path getRealStoreDir() override { return realStoreDir; }
+
+  void createUser(const std::string& userName, uid_t userId) override;
+
+  friend class DerivationGoal;
+  friend class SubstitutionGoal;
+};
+
+using Inode = std::pair<dev_t, ino_t>;
+using InodesSeen = std::set<Inode>;
+
+/* "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);
+
+}  // namespace nix