lix/src/libstore/remote-store.cc

#include "serialise.hh"
#include "util.hh"
#include "remote-store.hh"
#include "worker-protocol.hh"
#include "archive.hh"
#include "affinity.hh"
#include "globals.hh"
#include "derivations.hh"
#include "pool.hh"
#include "finally.hh"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#include <cstring>

namespace nix {


Path readStorePath(Store & store, Source & from)
{
    Path path = readString(from);
    store.assertStorePath(path);
    return path;
}


template<class T> T readStorePaths(Store & store, Source & from)
{
    T paths = readStrings<T>(from);
    for (auto & i : paths) store.assertStorePath(i);
    return paths;
}

template PathSet readStorePaths(Store & store, Source & from);
template Paths readStorePaths(Store & store, Source & from);

/* TODO: Separate these store impls into different files, give them better names */
RemoteStore::RemoteStore(const Params & params)
    : Store(params)
    , connections(make_ref<Pool<Connection>>(
            std::max(1, (int) maxConnections),
            [this]() { return openConnectionWrapper(); },
            [this](const ref<Connection> & r) {
                return
                    r->to.good()
                    && r->from.good()
                    && std::chrono::duration_cast<std::chrono::seconds>(
                        std::chrono::steady_clock::now() - r->startTime).count() < maxConnectionAge;
            }
            ))
{
}


ref<RemoteStore::Connection> RemoteStore::openConnectionWrapper()
{
    if (failed)
        throw Error("opening a connection to remote store '%s' previously failed", getUri());
    try {
        return openConnection();
    } catch (...) {
        failed = true;
        throw;
    }
}


UDSRemoteStore::UDSRemoteStore(const Params & params)
    : Store(params)
    , LocalFSStore(params)
    , RemoteStore(params)
{
}


UDSRemoteStore::UDSRemoteStore(std::string socket_path, const Params & params)
    : Store(params)
    , LocalFSStore(params)
    , RemoteStore(params)
    , path(socket_path)
{
}


std::string UDSRemoteStore::getUri()
{
    if (path) {
        return std::string("unix://") + *path;
    } else {
        return "daemon";
    }
}


ref<RemoteStore::Connection> UDSRemoteStore::openConnection()
{
    auto conn = make_ref<Connection>();

    /* Connect to a daemon that does the privileged work for us. */
    conn->fd = socket(PF_UNIX, SOCK_STREAM
        #ifdef SOCK_CLOEXEC
        | SOCK_CLOEXEC
        #endif
        , 0);
    if (!conn->fd)
        throw SysError("cannot create Unix domain socket");
    closeOnExec(conn->fd.get());

    string socketPath = path ? *path : settings.nixDaemonSocketFile;

    struct sockaddr_un addr;
    addr.sun_family = AF_UNIX;
    if (socketPath.size() + 1 >= sizeof(addr.sun_path))
        throw Error(format("socket path '%1%' is too long") % socketPath);
    strcpy(addr.sun_path, socketPath.c_str());

    if (::connect(conn->fd.get(), (struct sockaddr *) &addr, sizeof(addr)) == -1)
        throw SysError(format("cannot connect to daemon at '%1%'") % socketPath);

    conn->from.fd = conn->fd.get();
    conn->to.fd = conn->fd.get();

    conn->startTime = std::chrono::steady_clock::now();

    initConnection(*conn);

    return conn;
}


void RemoteStore::initConnection(Connection & conn)
{
    /* Send the magic greeting, check for the reply. */
    try {
        conn.to << WORKER_MAGIC_1;
        conn.to.flush();
        unsigned int magic = readInt(conn.from);
        if (magic != WORKER_MAGIC_2) throw Error("protocol mismatch");

        conn.from >> conn.daemonVersion;
        if (GET_PROTOCOL_MAJOR(conn.daemonVersion) != GET_PROTOCOL_MAJOR(PROTOCOL_VERSION))
            throw Error("Nix daemon protocol version not supported");
        if (GET_PROTOCOL_MINOR(conn.daemonVersion) < 10)
            throw Error("the Nix daemon version is too old");
        conn.to << PROTOCOL_VERSION;

        if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 14) {
            int cpu = settings.lockCPU ? lockToCurrentCPU() : -1;
            if (cpu != -1)
                conn.to << 1 << cpu;
            else
                conn.to << 0;
        }

        if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 11)
            conn.to << false;

        auto ex = conn.processStderr();
        if (ex) std::rethrow_exception(ex);
    }
    catch (Error & e) {
        throw Error("cannot open connection to remote store '%s': %s", getUri(), e.what());
    }

    setOptions(conn);
}


void RemoteStore::setOptions(Connection & conn)
{
    conn.to << wopSetOptions
       << settings.keepFailed
       << settings.keepGoing
       << settings.tryFallback
       << verbosity
       << settings.maxBuildJobs
       << settings.maxSilentTime
       << true
       << (settings.verboseBuild ? lvlError : lvlVomit)
       << 0 // obsolete log type
       << 0 /* obsolete print build trace */
       << settings.buildCores
       << settings.useSubstitutes;

    if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 12) {
        std::map<std::string, Config::SettingInfo> overrides;
        globalConfig.getSettings(overrides, true);
        overrides.erase(settings.keepFailed.name);
        overrides.erase(settings.keepGoing.name);
        overrides.erase(settings.tryFallback.name);
        overrides.erase(settings.maxBuildJobs.name);
        overrides.erase(settings.maxSilentTime.name);
        overrides.erase(settings.buildCores.name);
        overrides.erase(settings.useSubstitutes.name);
        conn.to << overrides.size();
        for (auto & i : overrides)
            conn.to << i.first << i.second.value;
    }

    auto ex = conn.processStderr();
    if (ex) std::rethrow_exception(ex);
}


/* A wrapper around Pool<RemoteStore::Connection>::Handle that marks
   the connection as bad (causing it to be closed) if a non-daemon
   exception is thrown before the handle is closed. Such an exception
   causes a deviation from the expected protocol and therefore a
   desynchronization between the client and daemon. */
struct ConnectionHandle
{
    Pool<RemoteStore::Connection>::Handle handle;
    bool daemonException = false;

    ConnectionHandle(Pool<RemoteStore::Connection>::Handle && handle)
        : handle(std::move(handle))
    { }

    ConnectionHandle(ConnectionHandle && h)
        : handle(std::move(h.handle))
    { }

    ~ConnectionHandle()
    {
        if (!daemonException && std::uncaught_exception()) {
            handle.markBad();
            debug("closing daemon connection because of an exception");
        }
    }

    RemoteStore::Connection * operator -> () { return &*handle; }

    void processStderr(Sink * sink = 0, Source * source = 0)
    {
        auto ex = handle->processStderr(sink, source);
        if (ex) {
            daemonException = true;
            std::rethrow_exception(ex);
        }
    }
};


ConnectionHandle RemoteStore::getConnection()
{
    return ConnectionHandle(connections->get());
}


bool RemoteStore::isValidPathUncached(const Path & path)
{
    auto conn(getConnection());
    conn->to << wopIsValidPath << path;
    conn.processStderr();
    return readInt(conn->from);
}


PathSet RemoteStore::queryValidPaths(const PathSet & paths, SubstituteFlag maybeSubstitute)
{
    auto conn(getConnection());
    if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 12) {
        PathSet res;
        for (auto & i : paths)
            if (isValidPath(i)) res.insert(i);
        return res;
    } else {
        conn->to << wopQueryValidPaths << paths;
        conn.processStderr();
        return readStorePaths<PathSet>(*this, conn->from);
    }
}


PathSet RemoteStore::queryAllValidPaths()
{
    auto conn(getConnection());
    conn->to << wopQueryAllValidPaths;
    conn.processStderr();
    return readStorePaths<PathSet>(*this, conn->from);
}


PathSet RemoteStore::querySubstitutablePaths(const PathSet & paths)
{
    auto conn(getConnection());
    if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 12) {
        PathSet res;
        for (auto & i : paths) {
            conn->to << wopHasSubstitutes << i;
            conn.processStderr();
            if (readInt(conn->from)) res.insert(i);
        }
        return res;
    } else {
        conn->to << wopQuerySubstitutablePaths << paths;
        conn.processStderr();
        return readStorePaths<PathSet>(*this, conn->from);
    }
}


void RemoteStore::querySubstitutablePathInfos(const PathSet & paths,
    SubstitutablePathInfos & infos)
{
    if (paths.empty()) return;

    auto conn(getConnection());

    if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 12) {

        for (auto & i : paths) {
            SubstitutablePathInfo info;
            conn->to << wopQuerySubstitutablePathInfo << i;
            conn.processStderr();
            unsigned int reply = readInt(conn->from);
            if (reply == 0) continue;
            info.deriver = readString(conn->from);
            if (info.deriver != "") assertStorePath(info.deriver);
            info.references = readStorePaths<PathSet>(*this, conn->from);
            info.downloadSize = readLongLong(conn->from);
            info.narSize = readLongLong(conn->from);
            infos[i] = info;
        }

    } else {

        conn->to << wopQuerySubstitutablePathInfos << paths;
        conn.processStderr();
        size_t count = readNum<size_t>(conn->from);
        for (size_t n = 0; n < count; n++) {
            Path path = readStorePath(*this, conn->from);
            SubstitutablePathInfo & info(infos[path]);
            info.deriver = readString(conn->from);
            if (info.deriver != "") assertStorePath(info.deriver);
            info.references = readStorePaths<PathSet>(*this, conn->from);
            info.downloadSize = readLongLong(conn->from);
            info.narSize = readLongLong(conn->from);
        }

    }
}


void RemoteStore::queryPathInfoUncached(const Path & path,
    Callback<std::shared_ptr<ValidPathInfo>> callback) noexcept
{
    try {
        std::shared_ptr<ValidPathInfo> info;
        {
            auto conn(getConnection());
            conn->to << wopQueryPathInfo << path;
            try {
                conn.processStderr();
            } catch (Error & e) {
                // Ugly backwards compatibility hack.
                if (e.msg().find("is not valid") != std::string::npos)
                    throw InvalidPath(e.what());
                throw;
            }
            if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 17) {
                bool valid; conn->from >> valid;
                if (!valid) throw InvalidPath(format("path '%s' is not valid") % path);
            }
            info = std::make_shared<ValidPathInfo>();
            info->path = path;
            info->deriver = readString(conn->from);
            if (info->deriver != "") assertStorePath(info->deriver);
            info->narHash = Hash(readString(conn->from), htSHA256);
            info->references = readStorePaths<PathSet>(*this, conn->from);
            conn->from >> info->registrationTime >> info->narSize;
            if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 16) {
                conn->from >> info->ultimate;
                info->sigs = readStrings<StringSet>(conn->from);
                conn->from >> info->ca;
            }
        }
        callback(std::move(info));
    } catch (...) { callback.rethrow(); }
}


void RemoteStore::queryReferrers(const Path & path,
    PathSet & referrers)
{
    auto conn(getConnection());
    conn->to << wopQueryReferrers << path;
    conn.processStderr();
    PathSet referrers2 = readStorePaths<PathSet>(*this, conn->from);
    referrers.insert(referrers2.begin(), referrers2.end());
}


PathSet RemoteStore::queryValidDerivers(const Path & path)
{
    auto conn(getConnection());
    conn->to << wopQueryValidDerivers << path;
    conn.processStderr();
    return readStorePaths<PathSet>(*this, conn->from);
}


PathSet RemoteStore::queryDerivationOutputs(const Path & path)
{
    auto conn(getConnection());
    conn->to << wopQueryDerivationOutputs << path;
    conn.processStderr();
    return readStorePaths<PathSet>(*this, conn->from);
}


PathSet RemoteStore::queryDerivationOutputNames(const Path & path)
{
    auto conn(getConnection());
    conn->to << wopQueryDerivationOutputNames << path;
    conn.processStderr();
    return readStrings<PathSet>(conn->from);
}


Path RemoteStore::queryPathFromHashPart(const string & hashPart)
{
    auto conn(getConnection());
    conn->to << wopQueryPathFromHashPart << hashPart;
    conn.processStderr();
    Path path = readString(conn->from);
    if (!path.empty()) assertStorePath(path);
    return path;
}


void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
    RepairFlag repair, CheckSigsFlag checkSigs, std::shared_ptr<FSAccessor> accessor)
{
    auto conn(getConnection());

    if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 18) {
        conn->to << wopImportPaths;

        auto source2 = sinkToSource([&](Sink & sink) {
            sink << 1 // == path follows
                ;
            copyNAR(source, sink);
            sink
                << exportMagic
                << info.path
                << info.references
                << info.deriver
                << 0 // == no legacy signature
                << 0 // == no path follows
                ;
        });

        conn.processStderr(0, source2.get());

        auto importedPaths = readStorePaths<PathSet>(*this, conn->from);
        assert(importedPaths.size() <= 1);
    }

    else {
        conn->to << wopAddToStoreNar
                 << info.path << info.deriver << info.narHash.to_string(Base16, false)
                 << info.references << info.registrationTime << info.narSize
                 << info.ultimate << info.sigs << info.ca
                 << repair << !checkSigs;
        bool tunnel = GET_PROTOCOL_MINOR(conn->daemonVersion) >= 21;
        if (!tunnel) copyNAR(source, conn->to);
        conn.processStderr(0, tunnel ? &source : nullptr);
    }
}


Path RemoteStore::addToStore(const string & name, const Path & _srcPath,
    bool recursive, HashType hashAlgo, PathFilter & filter, RepairFlag repair)
{
    if (repair) throw Error("repairing is not supported when building through the Nix daemon");

    auto conn(getConnection());

    Path srcPath(absPath(_srcPath));

    conn->to << wopAddToStore << name
       << ((hashAlgo == htSHA256 && recursive) ? 0 : 1) /* backwards compatibility hack */
       << (recursive ? 1 : 0)
       << printHashType(hashAlgo);

    try {
        conn->to.written = 0;
        conn->to.warn = true;
        connections->incCapacity();
        {
            Finally cleanup([&]() { connections->decCapacity(); });
            dumpPath(srcPath, conn->to, filter);
        }
        conn->to.warn = false;
        conn.processStderr();
    } catch (SysError & e) {
        /* Daemon closed while we were sending the path. Probably OOM
           or I/O error. */
        if (e.errNo == EPIPE)
            try {
                conn.processStderr();
            } catch (EndOfFile & e) { }
        throw;
    }

    return readStorePath(*this, conn->from);
}


Path RemoteStore::addTextToStore(const string & name, const string & s,
    const PathSet & references, RepairFlag repair)
{
    if (repair) throw Error("repairing is not supported when building through the Nix daemon");

    auto conn(getConnection());
    conn->to << wopAddTextToStore << name << s << references;

    conn.processStderr();
    return readStorePath(*this, conn->from);
}


void RemoteStore::buildPaths(const PathSet & drvPaths, BuildMode buildMode)
{
    auto conn(getConnection());
    conn->to << wopBuildPaths;
    if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 13) {
        conn->to << drvPaths;
        if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 15)
            conn->to << buildMode;
        else
            /* Old daemons did not take a 'buildMode' parameter, so we
               need to validate it here on the client side.  */
            if (buildMode != bmNormal)
                throw Error("repairing or checking is not supported when building through the Nix daemon");
    } else {
        /* For backwards compatibility with old daemons, strip output
           identifiers. */
        PathSet drvPaths2;
        for (auto & i : drvPaths)
            drvPaths2.insert(string(i, 0, i.find('!')));
        conn->to << drvPaths2;
    }
    conn.processStderr();
    readInt(conn->from);
}


BuildResult RemoteStore::buildDerivation(const Path & drvPath, const BasicDerivation & drv,
    BuildMode buildMode)
{
    auto conn(getConnection());
    conn->to << wopBuildDerivation << drvPath << drv << buildMode;
    conn.processStderr();
    BuildResult res;
    unsigned int status;
    conn->from >> status >> res.errorMsg;
    res.status = (BuildResult::Status) status;
    return res;
}


void RemoteStore::ensurePath(const Path & path)
{
    auto conn(getConnection());
    conn->to << wopEnsurePath << path;
    conn.processStderr();
    readInt(conn->from);
}


void RemoteStore::addTempRoot(const Path & path)
{
    auto conn(getConnection());
    conn->to << wopAddTempRoot << path;
    conn.processStderr();
    readInt(conn->from);
}


void RemoteStore::addIndirectRoot(const Path & path)
{
    auto conn(getConnection());
    conn->to << wopAddIndirectRoot << path;
    conn.processStderr();
    readInt(conn->from);
}


void RemoteStore::syncWithGC()
{
    auto conn(getConnection());
    conn->to << wopSyncWithGC;
    conn.processStderr();
    readInt(conn->from);
}


Roots RemoteStore::findRoots(bool censor)
{
    auto conn(getConnection());
    conn->to << wopFindRoots;
    conn.processStderr();
    size_t count = readNum<size_t>(conn->from);
    Roots result;
    while (count--) {
        Path link = readString(conn->from);
        Path target = readStorePath(*this, conn->from);
        result[target].emplace(link);
    }
    return result;
}


void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results)
{
    auto conn(getConnection());

    conn->to
        << wopCollectGarbage << options.action << options.pathsToDelete << options.ignoreLiveness
        << options.maxFreed
        /* removed options */
        << 0 << 0 << 0;

    conn.processStderr();

    results.paths = readStrings<PathSet>(conn->from);
    results.bytesFreed = readLongLong(conn->from);
    readLongLong(conn->from); // obsolete

    {
        auto state_(Store::state.lock());
        state_->pathInfoCache.clear();
    }
}


void RemoteStore::optimiseStore()
{
    auto conn(getConnection());
    conn->to << wopOptimiseStore;
    conn.processStderr();
    readInt(conn->from);
}


bool RemoteStore::verifyStore(bool checkContents, RepairFlag repair)
{
    auto conn(getConnection());
    conn->to << wopVerifyStore << checkContents << repair;
    conn.processStderr();
    return readInt(conn->from);
}


void RemoteStore::addSignatures(const Path & storePath, const StringSet & sigs)
{
    auto conn(getConnection());
    conn->to << wopAddSignatures << storePath << sigs;
    conn.processStderr();
    readInt(conn->from);
}


void RemoteStore::queryMissing(const PathSet & targets,
    PathSet & willBuild, PathSet & willSubstitute, PathSet & unknown,
    unsigned long long & downloadSize, unsigned long long & narSize)
{
    {
        auto conn(getConnection());
        if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 19)
            // Don't hold the connection handle in the fallback case
            // to prevent a deadlock.
            goto fallback;
        conn->to << wopQueryMissing << targets;
        conn.processStderr();
        willBuild = readStorePaths<PathSet>(*this, conn->from);
        willSubstitute = readStorePaths<PathSet>(*this, conn->from);
        unknown = readStorePaths<PathSet>(*this, conn->from);
        conn->from >> downloadSize >> narSize;
        return;
    }

 fallback:
    return Store::queryMissing(targets, willBuild, willSubstitute,
        unknown, downloadSize, narSize);
}


void RemoteStore::connect()
{
    auto conn(getConnection());
}


unsigned int RemoteStore::getProtocol()
{
    auto conn(connections->get());
    return conn->daemonVersion;
}


void RemoteStore::flushBadConnections()
{
    connections->flushBad();
}


RemoteStore::Connection::~Connection()
{
    try {
        to.flush();
    } catch (...) {
        ignoreException();
    }
}


static Logger::Fields readFields(Source & from)
{
    Logger::Fields fields;
    size_t size = readInt(from);
    for (size_t n = 0; n < size; n++) {
        auto type = (decltype(Logger::Field::type)) readInt(from);
        if (type == Logger::Field::tInt)
            fields.push_back(readNum<uint64_t>(from));
        else if (type == Logger::Field::tString)
            fields.push_back(readString(from));
        else
            throw Error("got unsupported field type %x from Nix daemon", (int) type);
    }
    return fields;
}


std::exception_ptr RemoteStore::Connection::processStderr(Sink * sink, Source * source)
{
    to.flush();

    while (true) {

        auto msg = readNum<uint64_t>(from);

        if (msg == STDERR_WRITE) {
            string s = readString(from);
            if (!sink) throw Error("no sink");
            (*sink)(s);
        }

        else if (msg == STDERR_READ) {
            if (!source) throw Error("no source");
            size_t len = readNum<size_t>(from);
            auto buf = std::make_unique<unsigned char[]>(len);
            writeString(buf.get(), source->read(buf.get(), len), to);
            to.flush();
        }

        else if (msg == STDERR_ERROR) {
            string error = readString(from);
            unsigned int status = readInt(from);
            return std::make_exception_ptr(Error(status, error));
        }

        else if (msg == STDERR_NEXT)
            printError(chomp(readString(from)));

        else if (msg == STDERR_START_ACTIVITY) {
            auto act = readNum<ActivityId>(from);
            auto lvl = (Verbosity) readInt(from);
            auto type = (ActivityType) readInt(from);
            auto s = readString(from);
            auto fields = readFields(from);
            auto parent = readNum<ActivityId>(from);
            logger->startActivity(act, lvl, type, s, fields, parent);
        }

        else if (msg == STDERR_STOP_ACTIVITY) {
            auto act = readNum<ActivityId>(from);
            logger->stopActivity(act);
        }

        else if (msg == STDERR_RESULT) {
            auto act = readNum<ActivityId>(from);
            auto type = (ResultType) readInt(from);
            auto fields = readFields(from);
            logger->result(act, type, fields);
        }

        else if (msg == STDERR_LAST)
            break;

        else
            throw Error("got unknown message type %x from Nix daemon", msg);
    }

    return nullptr;
}

static std::string uriScheme = "unix://";

static RegisterStoreImplementation regStore([](
    const std::string & uri, const Store::Params & params)
    -> std::shared_ptr<Store>
{
    if (std::string(uri, 0, uriScheme.size()) != uriScheme) return 0;
    return std::make_shared<UDSRemoteStore>(std::string(uri, uriScheme.size()), params);
});

}