#pragma once #include "hash.hh" #include "serialise.hh" #include "crypto.hh" #include "lru-cache.hh" #include "sync.hh" #include "globals.hh" #include "config.hh" #include #include #include #include #include #include #include namespace nix { MakeError(SubstError, Error) MakeError(BuildError, Error) /* denotes a permanent build failure */ MakeError(InvalidPath, Error) MakeError(Unsupported, Error) MakeError(SubstituteGone, Error) MakeError(SubstituterDisabled, Error) MakeError(NotInStore, Error) struct BasicDerivation; struct Derivation; class FSAccessor; class NarInfoDiskCache; class Store; class JSONPlaceholder; enum RepairFlag : bool { NoRepair = false, Repair = true }; enum CheckSigsFlag : bool { NoCheckSigs = false, CheckSigs = true }; enum SubstituteFlag : bool { NoSubstitute = false, Substitute = true }; enum AllowInvalidFlag : bool { DisallowInvalid = false, AllowInvalid = true }; /* Size of the hash part of store paths, in base-32 characters. */ const size_t storePathHashLen = 32; // i.e. 160 bits /* Magic header of exportPath() output (obsolete). */ const uint32_t exportMagic = 0x4558494e; typedef std::unordered_map> Roots; struct GCOptions { /* Garbage collector operation: - `gcReturnLive': return the set of paths reachable from (i.e. in the closure of) the roots. - `gcReturnDead': return the set of paths not reachable from the roots. - `gcDeleteDead': actually delete the latter set. - `gcDeleteSpecific': delete the paths listed in `pathsToDelete', insofar as they are not reachable. */ typedef enum { gcReturnLive, gcReturnDead, gcDeleteDead, gcDeleteSpecific, } GCAction; GCAction action{gcDeleteDead}; /* If `ignoreLiveness' is set, then reachability from the roots is ignored (dangerous!). However, the paths must still be unreferenced *within* the store (i.e., there can be no other store paths that depend on them). */ bool ignoreLiveness{false}; /* For `gcDeleteSpecific', the paths to delete. */ PathSet pathsToDelete; /* Stop after at least `maxFreed' bytes have been freed. */ unsigned long long maxFreed{std::numeric_limits::max()}; }; struct GCResults { /* Depending on the action, the GC roots, or the paths that would be or have been deleted. */ PathSet paths; /* For `gcReturnDead', `gcDeleteDead' and `gcDeleteSpecific', the number of bytes that would be or was freed. */ unsigned long long bytesFreed = 0; }; struct SubstitutablePathInfo { Path deriver; PathSet references; unsigned long long downloadSize; /* 0 = unknown or inapplicable */ unsigned long long narSize; /* 0 = unknown */ }; typedef std::map SubstitutablePathInfos; struct ValidPathInfo { Path path; Path deriver; Hash narHash; PathSet references; time_t registrationTime = 0; uint64_t narSize = 0; // 0 = unknown uint64_t id; // internal use only /* Whether the path is ultimately trusted, that is, it's a derivation output that was built locally. */ bool ultimate = false; StringSet sigs; // note: not necessarily verified /* If non-empty, an assertion that the path is content-addressed, i.e., that the store path is computed from a cryptographic hash of the contents of the path, plus some other bits of data like the "name" part of the path. Such a path doesn't need signatures, since we don't have to trust anybody's claim that the path is the output of a particular derivation. (In the extensional store model, we have to trust that the *contents* of an output path of a derivation were actually produced by that derivation. In the intensional model, we have to trust that a particular output path was produced by a derivation; the path then implies the contents.) Ideally, the content-addressability assertion would just be a Boolean, and the store path would be computed from ‘storePathToName(path)’, ‘narHash’ and ‘references’. However, 1) we've accumulated several types of content-addressed paths over the years; and 2) fixed-output derivations support multiple hash algorithms and serialisation methods (flat file vs NAR). Thus, ‘ca’ has one of the following forms: * ‘text:sha256:’: For paths computed by makeTextPath() / addTextToStore(). * ‘fixed:::’: For paths computed by makeFixedOutputPath() / addToStore(). */ std::string ca; bool operator == (const ValidPathInfo & i) const { return path == i.path && narHash == i.narHash && references == i.references; } /* Return a fingerprint of the store path to be used in binary cache signatures. It contains the store path, the base-32 SHA-256 hash of the NAR serialisation of the path, the size of the NAR, and the sorted references. The size field is strictly speaking superfluous, but might prevent endless/excessive data attacks. */ std::string fingerprint() const; void sign(const SecretKey & secretKey); /* Return true iff the path is verifiably content-addressed. */ bool isContentAddressed(const Store & store) const; static const size_t maxSigs = std::numeric_limits::max(); /* Return the number of signatures on this .narinfo that were produced by one of the specified keys, or maxSigs if the path is content-addressed. */ size_t checkSignatures(const Store & store, const PublicKeys & publicKeys) const; /* Verify a single signature. */ bool checkSignature(const PublicKeys & publicKeys, const std::string & sig) const; Strings shortRefs() const; virtual ~ValidPathInfo() { } }; typedef list ValidPathInfos; enum BuildMode { bmNormal, bmRepair, bmCheck }; struct BuildResult { /* Note: don't remove status codes, and only add new status codes at the end of the list, to prevent client/server incompatibilities in the nix-store --serve protocol. */ enum Status { Built = 0, Substituted, AlreadyValid, PermanentFailure, InputRejected, OutputRejected, TransientFailure, // possibly transient CachedFailure, // no longer used TimedOut, MiscFailure, DependencyFailed, LogLimitExceeded, NotDeterministic, } status = MiscFailure; std::string errorMsg; /* How many times this build was performed. */ unsigned int timesBuilt = 0; /* If timesBuilt > 1, whether some builds did not produce the same result. (Note that 'isNonDeterministic = false' does not mean the build is deterministic, just that we don't have evidence of non-determinism.) */ bool isNonDeterministic = false; /* The start/stop times of the build (or one of the rounds, if it was repeated). */ time_t startTime = 0, stopTime = 0; bool success() { return status == Built || status == Substituted || status == AlreadyValid; } }; class Store : public std::enable_shared_from_this, public Config { public: typedef std::map Params; const PathSetting storeDir_{this, false, settings.nixStore, "store", "path to the Nix store"}; const Path storeDir = storeDir_; const Setting pathInfoCacheSize{this, 65536, "path-info-cache-size", "size of the in-memory store path information cache"}; const Setting isTrusted{this, false, "trusted", "whether paths from this store can be used as substitutes even when they lack trusted signatures"}; protected: struct State { LRUCache> pathInfoCache; }; Sync state; std::shared_ptr diskCache; Store(const Params & params); public: virtual ~Store() { } virtual std::string getUri() = 0; /* Return true if ‘path’ is in the Nix store (but not the Nix store itself). */ bool isInStore(const Path & path) const; /* Return true if ‘path’ is a store path, i.e. a direct child of the Nix store. */ bool isStorePath(const Path & path) const; /* Throw an exception if ‘path’ is not a store path. */ void assertStorePath(const Path & path) const; /* Chop off the parts after the top-level store name, e.g., /nix/store/abcd-foo/bar => /nix/store/abcd-foo. */ Path toStorePath(const Path & path) const; /* Follow symlinks until we end up with a path in the Nix store. */ Path followLinksToStore(const Path & path) const; /* Same as followLinksToStore(), but apply toStorePath() to the result. */ Path followLinksToStorePath(const Path & path) const; /* Constructs a unique store path name. */ Path makeStorePath(const string & type, const Hash & hash, const string & name) const; Path makeOutputPath(const string & id, const Hash & hash, const string & name) const; Path makeFixedOutputPath(bool recursive, const Hash & hash, const string & name) const; Path makeTextPath(const string & name, const Hash & hash, const PathSet & references) const; /* This is the preparatory part of addToStore(); it computes the store path to which srcPath is to be copied. Returns the store path and the cryptographic hash of the contents of srcPath. */ std::pair computeStorePathForPath(const string & name, const Path & srcPath, bool recursive = true, HashType hashAlgo = htSHA256, PathFilter & filter = defaultPathFilter) const; /* Preparatory part of addTextToStore(). !!! Computation of the path should take the references given to addTextToStore() into account, otherwise we have a (relatively minor) security hole: a caller can register a source file with bogus references. If there are too many references, the path may not be garbage collected when it has to be (not really a problem, the caller could create a root anyway), or it may be garbage collected when it shouldn't be (more serious). Hashing the references would solve this (bogus references would simply yield a different store path, so other users wouldn't be affected), but it has some backwards compatibility issues (the hashing scheme changes), so I'm not doing that for now. */ Path computeStorePathForText(const string & name, const string & s, const PathSet & references) const; /* Check whether a path is valid. */ bool isValidPath(const Path & path); protected: virtual bool isValidPathUncached(const Path & path); public: /* Query which of the given paths is valid. Optionally, try to substitute missing paths. */ virtual PathSet queryValidPaths(const PathSet & paths, SubstituteFlag maybeSubstitute = NoSubstitute); /* Query the set of all valid paths. Note that for some store backends, the name part of store paths may be omitted (i.e. you'll get /nix/store/ rather than /nix/store/-). Use queryPathInfo() to obtain the full store path. */ virtual PathSet queryAllValidPaths() { unsupported("queryAllValidPaths"); } /* Query information about a valid path. It is permitted to omit the name part of the store path. */ ref queryPathInfo(const Path & path); /* Asynchronous version of queryPathInfo(). */ void queryPathInfo(const Path & path, Callback> callback) noexcept; protected: virtual void queryPathInfoUncached(const Path & path, Callback> callback) noexcept = 0; public: /* Queries the set of incoming FS references for a store path. The result is not cleared. */ virtual void queryReferrers(const Path & path, PathSet & referrers) { unsupported("queryReferrers"); } /* Return all currently valid derivations that have `path' as an output. (Note that the result of `queryDeriver()' is the derivation that was actually used to produce `path', which may not exist anymore.) */ virtual PathSet queryValidDerivers(const Path & path) { return {}; }; /* Query the outputs of the derivation denoted by `path'. */ virtual PathSet queryDerivationOutputs(const Path & path) { unsupported("queryDerivationOutputs"); } /* Query the output names of the derivation denoted by `path'. */ virtual StringSet queryDerivationOutputNames(const Path & path) { unsupported("queryDerivationOutputNames"); } /* Query the full store path given the hash part of a valid store path, or "" if the path doesn't exist. */ virtual Path queryPathFromHashPart(const string & hashPart) = 0; /* Query which of the given paths have substitutes. */ virtual PathSet querySubstitutablePaths(const PathSet & paths) { return {}; }; /* Query substitute info (i.e. references, derivers and download sizes) of a set of paths. If a path does not have substitute info, it's omitted from the resulting ‘infos’ map. */ virtual void querySubstitutablePathInfos(const PathSet & paths, SubstitutablePathInfos & infos) { return; }; virtual bool wantMassQuery() { return false; } /* Import a path into the store. */ virtual void addToStore(const ValidPathInfo & info, Source & narSource, RepairFlag repair = NoRepair, CheckSigsFlag checkSigs = CheckSigs, std::shared_ptr accessor = 0); // FIXME: remove virtual void addToStore(const ValidPathInfo & info, const ref & nar, RepairFlag repair = NoRepair, CheckSigsFlag checkSigs = CheckSigs, std::shared_ptr accessor = 0); /* Copy the contents of a path to the store and register the validity the resulting path. The resulting path is returned. The function object `filter' can be used to exclude files (see libutil/archive.hh). */ virtual Path addToStore(const string & name, const Path & srcPath, bool recursive = true, HashType hashAlgo = htSHA256, PathFilter & filter = defaultPathFilter, RepairFlag repair = NoRepair) = 0; /* Like addToStore, but the contents written to the output path is a regular file containing the given string. */ virtual Path addTextToStore(const string & name, const string & s, const PathSet & references, RepairFlag repair = NoRepair) = 0; /* Write a NAR dump of a store path. */ virtual void narFromPath(const Path & path, Sink & sink) = 0; /* For each path, if it's a derivation, build it. Building a derivation means ensuring that the output paths are valid. If they are already valid, this is a no-op. Otherwise, validity can be reached in two ways. First, if the output paths is substitutable, then build the path that way. Second, the output paths can be created by running the builder, after recursively building any sub-derivations. For inputs that are not derivations, substitute them. */ virtual void buildPaths(const PathSet & paths, BuildMode buildMode = bmNormal); /* Build a single non-materialized derivation (i.e. not from an on-disk .drv file). Note that ‘drvPath’ is only used for informational purposes. */ virtual BuildResult buildDerivation(const Path & drvPath, const BasicDerivation & drv, BuildMode buildMode = bmNormal) = 0; /* Ensure that a path is valid. If it is not currently valid, it may be made valid by running a substitute (if defined for the path). */ virtual void ensurePath(const Path & path) = 0; /* Add a store path as a temporary root of the garbage collector. The root disappears as soon as we exit. */ virtual void addTempRoot(const Path & path) { unsupported("addTempRoot"); } /* Add an indirect root, which is merely a symlink to `path' from /nix/var/nix/gcroots/auto/. `path' is supposed to be a symlink to a store path. The garbage collector will automatically remove the indirect root when it finds that `path' has disappeared. */ virtual void addIndirectRoot(const Path & path) { unsupported("addIndirectRoot"); } /* Acquire the global GC lock, then immediately release it. This function must be called after registering a new permanent root, but before exiting. Otherwise, it is possible that a running garbage collector doesn't see the new root and deletes the stuff we've just built. By acquiring the lock briefly, we ensure that either: - The collector is already running, and so we block until the collector is finished. The collector will know about our *temporary* locks, which should include whatever it is we want to register as a permanent lock. - The collector isn't running, or it's just started but hasn't acquired the GC lock yet. In that case we get and release the lock right away, then exit. The collector scans the permanent root and sees our's. In either case the permanent root is seen by the collector. */ virtual void syncWithGC() { }; /* Find the roots of the garbage collector. Each root is a pair (link, storepath) where `link' is the path of the symlink outside of the Nix store that point to `storePath'. If 'censor' is true, privacy-sensitive information about roots found in /proc is censored. */ virtual Roots findRoots(bool censor) { unsupported("findRoots"); } /* Perform a garbage collection. */ virtual void collectGarbage(const GCOptions & options, GCResults & results) { unsupported("collectGarbage"); } /* Return a string representing information about the path that can be loaded into the database using `nix-store --load-db' or `nix-store --register-validity'. */ string makeValidityRegistration(const PathSet & paths, bool showDerivers, bool showHash); /* Write a JSON representation of store path metadata, such as the hash and the references. If ‘includeImpureInfo’ is true, variable elements such as the registration time are included. If ‘showClosureSize’ is true, the closure size of each path is included. */ void pathInfoToJSON(JSONPlaceholder & jsonOut, const PathSet & storePaths, bool includeImpureInfo, bool showClosureSize, AllowInvalidFlag allowInvalid = DisallowInvalid); /* Return the size of the closure of the specified path, that is, the sum of the size of the NAR serialisation of each path in the closure. */ std::pair getClosureSize(const Path & storePath); /* Optimise the disk space usage of the Nix store by hard-linking files with the same contents. */ virtual void optimiseStore() { }; /* Check the integrity of the Nix store. Returns true if errors remain. */ virtual bool verifyStore(bool checkContents, RepairFlag repair = NoRepair) { return false; }; /* Return an object to access files in the Nix store. */ virtual ref getFSAccessor() { unsupported("getFSAccessor"); } /* Add signatures to the specified store path. The signatures are not verified. */ virtual void addSignatures(const Path & storePath, const StringSet & sigs) { unsupported("addSignatures"); } /* Utility functions. */ /* Read a derivation, after ensuring its existence through ensurePath(). */ Derivation derivationFromPath(const Path & drvPath); /* Place in `out' the set of all store paths in the file system closure of `storePath'; that is, all paths than can be directly or indirectly reached from it. `out' is not cleared. If `flipDirection' is true, the set of paths that can reach `storePath' is returned; that is, the closures under the `referrers' relation instead of the `references' relation is returned. */ virtual void computeFSClosure(const PathSet & paths, PathSet & out, bool flipDirection = false, bool includeOutputs = false, bool includeDerivers = false); void computeFSClosure(const Path & path, PathSet & out, bool flipDirection = false, bool includeOutputs = false, bool includeDerivers = false); /* Given a set of paths that are to be built, return the set of derivations that will be built, and the set of output paths that will be substituted. */ virtual void queryMissing(const PathSet & targets, PathSet & willBuild, PathSet & willSubstitute, PathSet & unknown, unsigned long long & downloadSize, unsigned long long & narSize); /* Sort a set of paths topologically under the references relation. If p refers to q, then p preceeds q in this list. */ Paths topoSortPaths(const PathSet & paths); /* Export multiple paths in the format expected by ‘nix-store --import’. */ void exportPaths(const Paths & paths, Sink & sink); void exportPath(const Path & path, Sink & sink); /* Import a sequence of NAR dumps created by exportPaths() into the Nix store. Optionally, the contents of the NARs are preloaded into the specified FS accessor to speed up subsequent access. */ Paths importPaths(Source & source, std::shared_ptr accessor, CheckSigsFlag checkSigs = CheckSigs); struct Stats { std::atomic narInfoRead{0}; std::atomic narInfoReadAverted{0}; std::atomic narInfoMissing{0}; std::atomic narInfoWrite{0}; std::atomic pathInfoCacheSize{0}; std::atomic narRead{0}; std::atomic narReadBytes{0}; std::atomic narReadCompressedBytes{0}; std::atomic narWrite{0}; std::atomic narWriteAverted{0}; std::atomic narWriteBytes{0}; std::atomic narWriteCompressedBytes{0}; std::atomic narWriteCompressionTimeMs{0}; }; const Stats & getStats(); /* Return the build log of the specified store path, if available, or null otherwise. */ virtual std::shared_ptr getBuildLog(const Path & path) { return nullptr; } /* Hack to allow long-running processes like hydra-queue-runner to occasionally flush their path info cache. */ void clearPathInfoCache() { state.lock()->pathInfoCache.clear(); } /* Establish a connection to the store, for store types that have a notion of connection. Otherwise this is a no-op. */ virtual void connect() { }; /* Get the protocol version of this store or it's connection. */ virtual unsigned int getProtocol() { return 0; }; /* Get the priority of the store, used to order substituters. In particular, binary caches can specify a priority field in their "nix-cache-info" file. Lower value means higher priority. */ virtual int getPriority() { return 0; } virtual Path toRealPath(const Path & storePath) { return storePath; } virtual void createUser(const std::string & userName, uid_t userId) { } protected: Stats stats; /* Unsupported methods. */ [[noreturn]] void unsupported(const std::string & op) { throw Unsupported("operation '%s' is not supported by store '%s'", op, getUri()); } }; class LocalFSStore : public virtual Store { public: // FIXME: the (Store*) cast works around a bug in gcc that causes // it to emit the call to the Option constructor. Clang works fine // either way. const PathSetting rootDir{(Store*) this, true, "", "root", "directory prefixed to all other paths"}; const PathSetting stateDir{(Store*) this, false, rootDir != "" ? rootDir + "/nix/var/nix" : settings.nixStateDir, "state", "directory where Nix will store state"}; const PathSetting logDir{(Store*) this, false, rootDir != "" ? rootDir + "/nix/var/log/nix" : settings.nixLogDir, "log", "directory where Nix will store state"}; const static string drvsLogDir; LocalFSStore(const Params & params); void narFromPath(const Path & path, Sink & sink) override; ref getFSAccessor() override; /* Register a permanent GC root. */ Path addPermRoot(const Path & storePath, const Path & gcRoot, bool indirect, bool allowOutsideRootsDir = false); virtual Path getRealStoreDir() { return storeDir; } Path toRealPath(const Path & storePath) override { assert(isInStore(storePath)); return getRealStoreDir() + "/" + std::string(storePath, storeDir.size() + 1); } std::shared_ptr getBuildLog(const Path & path) override; }; /* Extract the name part of the given store path. */ string storePathToName(const Path & path); /* Extract the hash part of the given store path. */ string storePathToHash(const Path & path); /* Check whether ‘name’ is a valid store path name part, i.e. contains only the characters [a-zA-Z0-9\+\-\.\_\?\=] and doesn't start with a dot. */ void checkStoreName(const string & name); /* Copy a path from one store to another. */ void copyStorePath(ref srcStore, ref dstStore, const Path & storePath, RepairFlag repair = NoRepair, CheckSigsFlag checkSigs = CheckSigs); /* Copy store paths from one store to another. The paths may be copied in parallel. They are copied in a topologically sorted order (i.e. if A is a reference of B, then A is copied before B), but the set of store paths is not automatically closed; use copyClosure() for that. */ void copyPaths(ref srcStore, ref dstStore, const PathSet & storePaths, RepairFlag repair = NoRepair, CheckSigsFlag checkSigs = CheckSigs, SubstituteFlag substitute = NoSubstitute); /* Copy the closure of the specified paths from one store to another. */ void copyClosure(ref srcStore, ref dstStore, const PathSet & storePaths, RepairFlag repair = NoRepair, CheckSigsFlag checkSigs = CheckSigs, SubstituteFlag substitute = NoSubstitute); /* Remove the temporary roots file for this process. Any temporary root becomes garbage after this point unless it has been registered as a (permanent) root. */ void removeTempRoots(); /* Return a Store object to access the Nix store denoted by ‘uri’ (slight misnomer...). Supported values are: * ‘local’: The Nix store in /nix/store and database in /nix/var/nix/db, accessed directly. * ‘daemon’: The Nix store accessed via a Unix domain socket connection to nix-daemon. * ‘unix://’: The Nix store accessed via a Unix domain socket connection to nix-daemon, with the socket located at . * ‘auto’ or ‘’: Equivalent to ‘local’ or ‘daemon’ depending on whether the user has write access to the local Nix store/database. * ‘file://’: A binary cache stored in . * ‘https://’: A binary cache accessed via HTTP. * ‘s3://’: A writable binary cache stored on Amazon's Simple Storage Service. * ‘ssh://[user@]’: A remote Nix store accessed by running ‘nix-store --serve’ via SSH. You can pass parameters to the store implementation by appending ‘?key=value&key=value&...’ to the URI. */ ref openStore(const std::string & uri = settings.storeUri.get(), const Store::Params & extraParams = Store::Params()); enum StoreType { tDaemon, tLocal, tOther }; StoreType getStoreType(const std::string & uri = settings.storeUri.get(), const std::string & stateDir = settings.nixStateDir); /* Return the default substituter stores, defined by the ‘substituters’ option and various legacy options. */ std::list> getDefaultSubstituters(); /* Store implementation registration. */ typedef std::function( const std::string & uri, const Store::Params & params)> OpenStore; struct RegisterStoreImplementation { typedef std::vector Implementations; static Implementations * implementations; RegisterStoreImplementation(OpenStore fun) { if (!implementations) implementations = new Implementations; implementations->push_back(fun); } }; /* Display a set of paths in human-readable form (i.e., between quotes and separated by commas). */ string showPaths(const PathSet & paths); ValidPathInfo decodeValidPathInfo(std::istream & str, bool hashGiven = false); /* Compute the content-addressability assertion (ValidPathInfo::ca) for paths created by makeFixedOutputPath() / addToStore(). */ std::string makeFixedOutputCA(bool recursive, const Hash & hash); /* Split URI into protocol+hierarchy part and its parameter set. */ std::pair splitUriAndParams(const std::string & uri); }