From 79e358ce6d2a2c34f365c24d68ddbab7461380f8 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 16 Oct 2018 23:36:15 +0200 Subject: [PATCH] RemoteStore: Close connection if an exception occurs Fixes #2075. --- src/libstore/remote-store.cc | 171 ++++++++++++++++++++++------------- src/libstore/remote-store.hh | 7 +- src/libutil/pool.hh | 6 +- 3 files changed, 121 insertions(+), 63 deletions(-) diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc index ea86ef052..ef8b0e53b 100644 --- a/src/libstore/remote-store.cc +++ b/src/libstore/remote-store.cc @@ -161,7 +161,8 @@ void RemoteStore::initConnection(Connection & conn) if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 11) conn.to << false; - conn.processStderr(); + 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()); @@ -195,22 +196,68 @@ void RemoteStore::setOptions(Connection & conn) conn.to << i.first << i.second.value; } - conn.processStderr(); + auto ex = conn.processStderr(); + if (ex) std::rethrow_exception(ex); +} + + +/* A wrapper around Pool::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::Handle handle; + bool daemonException = false; + + ConnectionHandle(Pool::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(connections->get()); + auto conn(getConnection()); conn->to << wopIsValidPath << path; - conn->processStderr(); + conn.processStderr(); return readInt(conn->from); } PathSet RemoteStore::queryValidPaths(const PathSet & paths, SubstituteFlag maybeSubstitute) { - auto conn(connections->get()); + auto conn(getConnection()); if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 12) { PathSet res; for (auto & i : paths) @@ -218,7 +265,7 @@ PathSet RemoteStore::queryValidPaths(const PathSet & paths, SubstituteFlag maybe return res; } else { conn->to << wopQueryValidPaths << paths; - conn->processStderr(); + conn.processStderr(); return readStorePaths(*this, conn->from); } } @@ -226,27 +273,27 @@ PathSet RemoteStore::queryValidPaths(const PathSet & paths, SubstituteFlag maybe PathSet RemoteStore::queryAllValidPaths() { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopQueryAllValidPaths; - conn->processStderr(); + conn.processStderr(); return readStorePaths(*this, conn->from); } PathSet RemoteStore::querySubstitutablePaths(const PathSet & paths) { - auto conn(connections->get()); + auto conn(getConnection()); if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 12) { PathSet res; for (auto & i : paths) { conn->to << wopHasSubstitutes << i; - conn->processStderr(); + conn.processStderr(); if (readInt(conn->from)) res.insert(i); } return res; } else { conn->to << wopQuerySubstitutablePaths << paths; - conn->processStderr(); + conn.processStderr(); return readStorePaths(*this, conn->from); } } @@ -257,14 +304,14 @@ void RemoteStore::querySubstitutablePathInfos(const PathSet & paths, { if (paths.empty()) return; - auto conn(connections->get()); + auto conn(getConnection()); if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 12) { for (auto & i : paths) { SubstitutablePathInfo info; conn->to << wopQuerySubstitutablePathInfo << i; - conn->processStderr(); + conn.processStderr(); unsigned int reply = readInt(conn->from); if (reply == 0) continue; info.deriver = readString(conn->from); @@ -278,7 +325,7 @@ void RemoteStore::querySubstitutablePathInfos(const PathSet & paths, } else { conn->to << wopQuerySubstitutablePathInfos << paths; - conn->processStderr(); + conn.processStderr(); size_t count = readNum(conn->from); for (size_t n = 0; n < count; n++) { Path path = readStorePath(*this, conn->from); @@ -300,10 +347,10 @@ void RemoteStore::queryPathInfoUncached(const Path & path, try { std::shared_ptr info; { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopQueryPathInfo << path; try { - conn->processStderr(); + conn.processStderr(); } catch (Error & e) { // Ugly backwards compatibility hack. if (e.msg().find("is not valid") != std::string::npos) @@ -335,9 +382,9 @@ void RemoteStore::queryPathInfoUncached(const Path & path, void RemoteStore::queryReferrers(const Path & path, PathSet & referrers) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopQueryReferrers << path; - conn->processStderr(); + conn.processStderr(); PathSet referrers2 = readStorePaths(*this, conn->from); referrers.insert(referrers2.begin(), referrers2.end()); } @@ -345,36 +392,36 @@ void RemoteStore::queryReferrers(const Path & path, PathSet RemoteStore::queryValidDerivers(const Path & path) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopQueryValidDerivers << path; - conn->processStderr(); + conn.processStderr(); return readStorePaths(*this, conn->from); } PathSet RemoteStore::queryDerivationOutputs(const Path & path) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopQueryDerivationOutputs << path; - conn->processStderr(); + conn.processStderr(); return readStorePaths(*this, conn->from); } PathSet RemoteStore::queryDerivationOutputNames(const Path & path) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopQueryDerivationOutputNames << path; - conn->processStderr(); + conn.processStderr(); return readStrings(conn->from); } Path RemoteStore::queryPathFromHashPart(const string & hashPart) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopQueryPathFromHashPart << hashPart; - conn->processStderr(); + conn.processStderr(); Path path = readString(conn->from); if (!path.empty()) assertStorePath(path); return path; @@ -384,7 +431,7 @@ Path RemoteStore::queryPathFromHashPart(const string & hashPart) void RemoteStore::addToStore(const ValidPathInfo & info, Source & source, RepairFlag repair, CheckSigsFlag checkSigs, std::shared_ptr accessor) { - auto conn(connections->get()); + auto conn(getConnection()); if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 18) { conn->to << wopImportPaths; @@ -403,7 +450,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source, ; }); - conn->processStderr(0, source2.get()); + conn.processStderr(0, source2.get()); auto importedPaths = readStorePaths(*this, conn->from); assert(importedPaths.size() <= 1); @@ -417,7 +464,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source, << repair << !checkSigs; bool tunnel = GET_PROTOCOL_MINOR(conn->daemonVersion) >= 21; if (!tunnel) copyNAR(source, conn->to); - conn->processStderr(0, tunnel ? &source : nullptr); + conn.processStderr(0, tunnel ? &source : nullptr); } } @@ -427,7 +474,7 @@ Path RemoteStore::addToStore(const string & name, const Path & _srcPath, { if (repair) throw Error("repairing is not supported when building through the Nix daemon"); - auto conn(connections->get()); + auto conn(getConnection()); Path srcPath(absPath(_srcPath)); @@ -445,13 +492,13 @@ Path RemoteStore::addToStore(const string & name, const Path & _srcPath, dumpPath(srcPath, conn->to, filter); } conn->to.warn = false; - conn->processStderr(); + 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(); + conn.processStderr(); } catch (EndOfFile & e) { } throw; } @@ -465,17 +512,17 @@ Path RemoteStore::addTextToStore(const string & name, const string & s, { if (repair) throw Error("repairing is not supported when building through the Nix daemon"); - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopAddTextToStore << name << s << references; - conn->processStderr(); + conn.processStderr(); return readStorePath(*this, conn->from); } void RemoteStore::buildPaths(const PathSet & drvPaths, BuildMode buildMode) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopBuildPaths; if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 13) { conn->to << drvPaths; @@ -494,7 +541,7 @@ void RemoteStore::buildPaths(const PathSet & drvPaths, BuildMode buildMode) drvPaths2.insert(string(i, 0, i.find('!'))); conn->to << drvPaths2; } - conn->processStderr(); + conn.processStderr(); readInt(conn->from); } @@ -502,9 +549,9 @@ void RemoteStore::buildPaths(const PathSet & drvPaths, BuildMode buildMode) BuildResult RemoteStore::buildDerivation(const Path & drvPath, const BasicDerivation & drv, BuildMode buildMode) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopBuildDerivation << drvPath << drv << buildMode; - conn->processStderr(); + conn.processStderr(); BuildResult res; unsigned int status; conn->from >> status >> res.errorMsg; @@ -515,45 +562,45 @@ BuildResult RemoteStore::buildDerivation(const Path & drvPath, const BasicDeriva void RemoteStore::ensurePath(const Path & path) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopEnsurePath << path; - conn->processStderr(); + conn.processStderr(); readInt(conn->from); } void RemoteStore::addTempRoot(const Path & path) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopAddTempRoot << path; - conn->processStderr(); + conn.processStderr(); readInt(conn->from); } void RemoteStore::addIndirectRoot(const Path & path) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopAddIndirectRoot << path; - conn->processStderr(); + conn.processStderr(); readInt(conn->from); } void RemoteStore::syncWithGC() { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopSyncWithGC; - conn->processStderr(); + conn.processStderr(); readInt(conn->from); } Roots RemoteStore::findRoots() { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopFindRoots; - conn->processStderr(); + conn.processStderr(); size_t count = readNum(conn->from); Roots result; while (count--) { @@ -567,7 +614,7 @@ Roots RemoteStore::findRoots() void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopCollectGarbage << options.action << options.pathsToDelete << options.ignoreLiveness @@ -575,7 +622,7 @@ void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results) /* removed options */ << 0 << 0 << 0; - conn->processStderr(); + conn.processStderr(); results.paths = readStrings(conn->from); results.bytesFreed = readLongLong(conn->from); @@ -590,27 +637,27 @@ void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results) void RemoteStore::optimiseStore() { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopOptimiseStore; - conn->processStderr(); + conn.processStderr(); readInt(conn->from); } bool RemoteStore::verifyStore(bool checkContents, RepairFlag repair) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopVerifyStore << checkContents << repair; - conn->processStderr(); + conn.processStderr(); return readInt(conn->from); } void RemoteStore::addSignatures(const Path & storePath, const StringSet & sigs) { - auto conn(connections->get()); + auto conn(getConnection()); conn->to << wopAddSignatures << storePath << sigs; - conn->processStderr(); + conn.processStderr(); readInt(conn->from); } @@ -620,13 +667,13 @@ void RemoteStore::queryMissing(const PathSet & targets, unsigned long long & downloadSize, unsigned long long & narSize) { { - auto conn(connections->get()); + 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(); + conn.processStderr(); willBuild = readStorePaths(*this, conn->from); willSubstitute = readStorePaths(*this, conn->from); unknown = readStorePaths(*this, conn->from); @@ -642,7 +689,7 @@ void RemoteStore::queryMissing(const PathSet & targets, void RemoteStore::connect() { - auto conn(connections->get()); + auto conn(getConnection()); } @@ -679,7 +726,7 @@ static Logger::Fields readFields(Source & from) } -void RemoteStore::Connection::processStderr(Sink * sink, Source * source) +std::exception_ptr RemoteStore::Connection::processStderr(Sink * sink, Source * source) { to.flush(); @@ -704,7 +751,7 @@ void RemoteStore::Connection::processStderr(Sink * sink, Source * source) else if (msg == STDERR_ERROR) { string error = readString(from); unsigned int status = readInt(from); - throw Error(status, error); + return std::make_exception_ptr(Error(status, error)); } else if (msg == STDERR_NEXT) @@ -738,6 +785,8 @@ void RemoteStore::Connection::processStderr(Sink * sink, Source * source) else throw Error("got unknown message type %x from Nix daemon", msg); } + + return nullptr; } static std::string uriScheme = "unix://"; diff --git a/src/libstore/remote-store.hh b/src/libstore/remote-store.hh index 9d768576b..7f9d7d1f5 100644 --- a/src/libstore/remote-store.hh +++ b/src/libstore/remote-store.hh @@ -14,6 +14,7 @@ class Pid; struct FdSink; struct FdSource; template class Pool; +struct ConnectionHandle; /* FIXME: RemoteStore is a misnomer - should be something like @@ -111,7 +112,7 @@ protected: virtual ~Connection(); - void processStderr(Sink * sink = 0, Source * source = 0); + std::exception_ptr processStderr(Sink * sink = 0, Source * source = 0); }; ref openConnectionWrapper(); @@ -124,6 +125,10 @@ protected: virtual void setOptions(Connection & conn); + ConnectionHandle getConnection(); + + friend class ConnectionHandle; + private: std::atomic_bool failed{false}; diff --git a/src/libutil/pool.hh b/src/libutil/pool.hh index 0b142b059..d49067bb9 100644 --- a/src/libutil/pool.hh +++ b/src/libutil/pool.hh @@ -97,6 +97,7 @@ public: private: Pool & pool; std::shared_ptr r; + bool bad = false; friend Pool; @@ -112,7 +113,8 @@ public: if (!r) return; { auto state_(pool.state.lock()); - state_->idle.push_back(ref(r)); + if (!bad) + state_->idle.push_back(ref(r)); assert(state_->inUse); state_->inUse--; } @@ -121,6 +123,8 @@ public: R * operator -> () { return &*r; } R & operator * () { return *r; } + + void markBad() { bad = true; } }; Handle get()