diff options
Diffstat (limited to 'third_party/nix/src/nix-daemon/nix-daemon-legacy.cc')
| -rw-r--r-- | third_party/nix/src/nix-daemon/nix-daemon-legacy.cc | 1185 |
1 files changed, 1185 insertions, 0 deletions
diff --git a/third_party/nix/src/nix-daemon/nix-daemon-legacy.cc b/third_party/nix/src/nix-daemon/nix-daemon-legacy.cc new file mode 100644 index 000000000000..97cf5195d35c --- /dev/null +++ b/third_party/nix/src/nix-daemon/nix-daemon-legacy.cc @@ -0,0 +1,1185 @@ +/* + NOTE: You are looking at the *previous* implementation of the Nix + daemon. This file is not in use, is only left in here for reference + and will be deleted from the codebase eventually. + */ + +#include <algorithm> +#include <cerrno> +#include <climits> +#include <csignal> +#include <cstring> + +#include <fcntl.h> +#include <glog/logging.h> +#include <grp.h> +#include <pwd.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/un.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "libmain/shared.hh" +#include "libproto/worker.pb.h" +#include "libstore/derivations.hh" +#include "libstore/globals.hh" +#include "libstore/local-store.hh" +#include "libstore/worker-protocol.hh" +#include "libutil/affinity.hh" +#include "libutil/archive.hh" +#include "libutil/finally.hh" +#include "libutil/monitor-fd.hh" +#include "libutil/serialise.hh" +#include "libutil/util.hh" +#include "nix/legacy.hh" + +using namespace nix; + +#ifndef __linux__ +#define SPLICE_F_MOVE 0 +static ssize_t splice(int fd_in, void* off_in, int fd_out, void* off_out, + size_t len, unsigned int flags) { + /* We ignore most parameters, we just have them for conformance with the linux + * syscall */ + std::vector<char> buf(8192); + auto read_count = read(fd_in, buf.data(), buf.size()); + if (read_count == -1) { + return read_count; + } + auto write_count = decltype(read_count)(0); + while (write_count < read_count) { + auto res = + write(fd_out, buf.data() + write_count, read_count - write_count); + if (res == -1) { + return res; + } + write_count += res; + } + return read_count; +} +#endif + +static FdSource from(STDIN_FILENO); +static FdSink to(STDOUT_FILENO); + +/* Logger that forwards log messages to the client, *if* we're in a + state where the protocol allows it (i.e., when canSendStderr is + true). */ +struct TunnelLogger { + struct State { + bool canSendStderr = false; + std::vector<std::string> pendingMsgs; + }; + + Sync<State> state_; + + unsigned int clientVersion; + + explicit TunnelLogger(unsigned int clientVersion) + : clientVersion(clientVersion) {} + + void enqueueMsg(const std::string& s) { + auto state(state_.lock()); + + if (state->canSendStderr) { + assert(state->pendingMsgs.empty()); + try { + to(s); + to.flush(); + } catch (...) { + /* Write failed; that means that the other side is + gone. */ + state->canSendStderr = false; + throw; + } + } else { + state->pendingMsgs.push_back(s); + } + } + + void log(const FormatOrString& fs) { + StringSink buf; + buf << STDERR_NEXT << (fs.s + "\n"); + enqueueMsg(*buf.s); + } + + /* startWork() means that we're starting an operation for which we + want to send out stderr to the client. */ + void startWork() { + auto state(state_.lock()); + state->canSendStderr = true; + + for (auto& msg : state->pendingMsgs) { + to(msg); + } + + state->pendingMsgs.clear(); + + to.flush(); + } + + /* stopWork() means that we're done; stop sending stderr to the + client. */ + void stopWork(bool success = true, const std::string& msg = "", + unsigned int status = 0) { + auto state(state_.lock()); + + state->canSendStderr = false; + + if (success) { + to << STDERR_LAST; + } else { + to << STDERR_ERROR << msg; + if (status != 0) { + to << status; + } + } + } + + void startActivity(const std::string& s) { + DLOG(INFO) << "startActivity(" << s << ")"; + if (GET_PROTOCOL_MINOR(clientVersion) < 20) { + if (!s.empty()) { + LOG(INFO) << s; + } + return; + } + + StringSink buf; + buf << STDERR_START_ACTIVITY << s; + enqueueMsg(*buf.s); + } +}; + +struct TunnelSink : Sink { + Sink& to; + explicit TunnelSink(Sink& to) : to(to) {} + void operator()(const unsigned char* data, size_t len) override { + to << STDERR_WRITE; + writeString(data, len, to); + } +}; + +struct TunnelSource : BufferedSource { + Source& from; + explicit TunnelSource(Source& from) : from(from) {} + + protected: + size_t readUnbuffered(unsigned char* data, size_t len) override { + to << STDERR_READ << len; + to.flush(); + size_t n = readString(data, len, from); + if (n == 0) { + throw EndOfFile("unexpected end-of-file"); + } + return n; + } +}; + +/* If the NAR archive contains a single file at top-level, then save + the contents of the file to `s'. Otherwise barf. */ +struct RetrieveRegularNARSink : ParseSink { + bool regular{true}; + std::string s; + + RetrieveRegularNARSink() {} + + void createDirectory(const Path& path) override { regular = false; } + + void receiveContents(unsigned char* data, unsigned int len) override { + s.append((const char*)data, len); + } + + void createSymlink(const Path& path, const std::string& target) override { + regular = false; + } +}; + +static void performOp(TunnelLogger* logger, const ref<Store>& store, + bool trusted, unsigned int clientVersion, Source& from, + Sink& to, unsigned int op) { + switch (op) { + case wopIsValidPath: { + /* 'readStorePath' could raise an error leading to the connection + being closed. To be able to recover from an invalid path error, + call 'startWork' early, and do 'assertStorePath' afterwards so + that the 'Error' exception handler doesn't close the + connection. */ + Path path = readString(from); + logger->startWork(); + store->assertStorePath(path); + bool result = store->isValidPath(path); + logger->stopWork(); + to << static_cast<uint64_t>(result); + break; + } + + case wopQueryValidPaths: { + auto paths = readStorePaths<PathSet>(*store, from); + logger->startWork(); + PathSet res = store->queryValidPaths(paths); + logger->stopWork(); + to << res; + break; + } + + case wopHasSubstitutes: { + Path path = readStorePath(*store, from); + logger->startWork(); + PathSet res = store->querySubstitutablePaths({path}); + logger->stopWork(); + to << static_cast<uint64_t>(res.find(path) != res.end()); + break; + } + + case wopQuerySubstitutablePaths: { + auto paths = readStorePaths<PathSet>(*store, from); + logger->startWork(); + PathSet res = store->querySubstitutablePaths(paths); + logger->stopWork(); + to << res; + break; + } + + case wopQueryPathHash: { + Path path = readStorePath(*store, from); + logger->startWork(); + auto hash = store->queryPathInfo(path)->narHash; + logger->stopWork(); + to << hash.to_string(Base16, false); + break; + } + + case wopQueryReferences: + case wopQueryReferrers: + case wopQueryValidDerivers: + case wopQueryDerivationOutputs: { + Path path = readStorePath(*store, from); + logger->startWork(); + PathSet paths; + if (op == wopQueryReferences) { + paths = store->queryPathInfo(path)->references; + } else if (op == wopQueryReferrers) { + store->queryReferrers(path, paths); + } else if (op == wopQueryValidDerivers) { + paths = store->queryValidDerivers(path); + } else { + paths = store->queryDerivationOutputs(path); + } + logger->stopWork(); + to << paths; + break; + } + + case wopQueryDerivationOutputNames: { + Path path = readStorePath(*store, from); + logger->startWork(); + StringSet names; + names = store->queryDerivationOutputNames(path); + logger->stopWork(); + to << names; + break; + } + + case wopQueryDeriver: { + Path path = readStorePath(*store, from); + logger->startWork(); + auto deriver = store->queryPathInfo(path)->deriver; + logger->stopWork(); + to << deriver; + break; + } + + case wopQueryPathFromHashPart: { + std::string hashPart = readString(from); + logger->startWork(); + Path path = store->queryPathFromHashPart(hashPart); + logger->stopWork(); + to << path; + break; + } + + case wopAddToStore: { + bool fixed = false; + bool recursive = false; + std::string hashType; + std::string baseName; + from >> baseName >> fixed /* obsolete */ >> recursive >> hashType; + /* Compatibility hack. */ + if (!fixed) { + hashType = "sha256"; + recursive = true; + } + HashType hashAlgo = parseHashType(hashType); + + TeeSource savedNAR(from); + RetrieveRegularNARSink savedRegular; + + if (recursive) { + /* Get the entire NAR dump from the client and save it to + a string so that we can pass it to + addToStoreFromDump(). */ + ParseSink sink; /* null sink; just parse the NAR */ + parseDump(sink, savedNAR); + } else { + parseDump(savedRegular, from); + } + + logger->startWork(); + if (!savedRegular.regular) { + throw Error("regular file expected"); + } + + auto store2 = store.dynamic_pointer_cast<LocalStore>(); + if (!store2) { + throw Error("operation is only supported by LocalStore"); + } + + Path path = store2->addToStoreFromDump( + recursive ? *savedNAR.data : savedRegular.s, baseName, recursive, + hashAlgo); + logger->stopWork(); + + to << path; + break; + } + + case wopAddTextToStore: { + std::string suffix = readString(from); + std::string s = readString(from); + auto refs = readStorePaths<PathSet>(*store, from); + logger->startWork(); + Path path = store->addTextToStore(suffix, s, refs, NoRepair); + logger->stopWork(); + to << path; + break; + } + + case wopExportPath: { + Path path = readStorePath(*store, from); + readInt(from); // obsolete + logger->startWork(); + TunnelSink sink(to); + store->exportPath(path, sink); + logger->stopWork(); + to << 1; + break; + } + + case wopImportPaths: { + logger->startWork(); + TunnelSource source(from); + Paths paths = store->importPaths(source, nullptr, + trusted ? NoCheckSigs : CheckSigs); + logger->stopWork(); + to << paths; + break; + } + + case wopBuildPaths: { + auto drvs = readStorePaths<PathSet>(*store, from); + BuildMode mode = bmNormal; + if (GET_PROTOCOL_MINOR(clientVersion) >= 15) { + mode = (BuildMode)readInt(from); + + /* Repairing is not atomic, so disallowed for "untrusted" + clients. */ + if (mode == bmRepair && !trusted) { + throw Error( + "repairing is not allowed because you are not in " + "'trusted-users'"); + } + } + logger->startWork(); + store->buildPaths(drvs, mode); + logger->stopWork(); + to << 1; + break; + } + + case wopBuildDerivation: { + Path drvPath = readStorePath(*store, from); + BasicDerivation drv; + readDerivation(from, *store, drv); + auto buildMode = (BuildMode)readInt(from); + logger->startWork(); + if (!trusted) { + throw Error("you are not privileged to build derivations"); + } + auto res = store->buildDerivation(drvPath, drv, buildMode); + logger->stopWork(); + to << res.status << res.errorMsg; + break; + } + + case wopEnsurePath: { + Path path = readStorePath(*store, from); + logger->startWork(); + store->ensurePath(path); + logger->stopWork(); + to << 1; + break; + } + + case wopAddTempRoot: { + Path path = readStorePath(*store, from); + logger->startWork(); + store->addTempRoot(path); + logger->stopWork(); + to << 1; + break; + } + + case wopAddIndirectRoot: { + Path path = absPath(readString(from)); + logger->startWork(); + store->addIndirectRoot(path); + logger->stopWork(); + to << 1; + break; + } + + case wopSyncWithGC: { + logger->startWork(); + store->syncWithGC(); + logger->stopWork(); + to << 1; + break; + } + + case wopFindRoots: { + logger->startWork(); + Roots roots = store->findRoots(!trusted); + logger->stopWork(); + + size_t size = 0; + for (auto& i : roots) { + size += i.second.size(); + } + + to << size; + + for (auto& [target, links] : roots) { + for (auto& link : links) { + to << link << target; + } + } + + break; + } + + case wopCollectGarbage: { + GCOptions options; + options.action = (GCOptions::GCAction)readInt(from); + options.pathsToDelete = readStorePaths<PathSet>(*store, from); + from >> options.ignoreLiveness >> options.maxFreed; + // obsolete fields + readInt(from); + readInt(from); + readInt(from); + + GCResults results; + + logger->startWork(); + if (options.ignoreLiveness) { + throw Error("you are not allowed to ignore liveness"); + } + store->collectGarbage(options, results); + logger->stopWork(); + + to << results.paths << results.bytesFreed << 0 /* obsolete */; + + break; + } + + case wopSetOptions: { + settings.keepFailed = readInt(from) != 0u; + settings.keepGoing = readInt(from) != 0u; + settings.tryFallback = readInt(from) != 0u; + readInt(from); // obsolete verbosity + settings.maxBuildJobs.assign(readInt(from)); + settings.maxSilentTime = readInt(from); + readInt(from); // obsolete useBuildHook + settings.verboseBuild = 0 == readInt(from); + readInt(from); // obsolete logType + readInt(from); // obsolete printBuildTrace + settings.buildCores = readInt(from); + settings.useSubstitutes = readInt(from) != 0u; + + StringMap overrides; + if (GET_PROTOCOL_MINOR(clientVersion) >= 12) { + unsigned int n = readInt(from); + for (unsigned int i = 0; i < n; i++) { + std::string name = readString(from); + std::string value = readString(from); + overrides.emplace(name, value); + } + } + + logger->startWork(); + + for (auto& i : overrides) { + auto& name(i.first); + auto& value(i.second); + + auto setSubstituters = [&](Setting<Strings>& res) { + if (name != res.name && res.aliases.count(name) == 0) { + return false; + } + StringSet trusted = settings.trustedSubstituters; + for (auto& s : settings.substituters.get()) { + trusted.insert(s); + } + Strings subs; + Strings ss = absl::StrSplit(value, absl::ByAnyChar(" \t\n\r"), + absl::SkipEmpty()); + for (auto& s : ss) { + if (trusted.count(s) != 0u) { + subs.push_back(s); + } else { + LOG(WARNING) << "ignoring untrusted substituter '" << s << "'"; + } + } + res = subs; + return true; + }; + + try { + if (name == "ssh-auth-sock") { // obsolete + ; + } else if (trusted || name == settings.buildTimeout.name || + name == "connect-timeout" || + (name == "builders" && value.empty())) { + settings.set(name, value); + } else if (setSubstituters(settings.substituters)) { + ; + } else if (setSubstituters(settings.extraSubstituters)) { + ; + } else { + LOG(WARNING) << "ignoring the user-specified setting '" << name + << "', because it is a " + << "restricted setting and you are not a trusted user"; + } + } catch (UsageError& e) { + LOG(WARNING) << e.what(); + } + } + + logger->stopWork(); + break; + } + + case wopQuerySubstitutablePathInfo: { + Path path = absPath(readString(from)); + logger->startWork(); + SubstitutablePathInfos infos; + store->querySubstitutablePathInfos({path}, infos); + logger->stopWork(); + auto i = infos.find(path); + if (i == infos.end()) { + to << 0; + } else { + to << 1 << i->second.deriver << i->second.references + << i->second.downloadSize << i->second.narSize; + } + break; + } + + case wopQuerySubstitutablePathInfos: { + auto paths = readStorePaths<PathSet>(*store, from); + logger->startWork(); + SubstitutablePathInfos infos; + store->querySubstitutablePathInfos(paths, infos); + logger->stopWork(); + to << infos.size(); + for (auto& i : infos) { + to << i.first << i.second.deriver << i.second.references + << i.second.downloadSize << i.second.narSize; + } + break; + } + + case wopQueryAllValidPaths: { + logger->startWork(); + PathSet paths = store->queryAllValidPaths(); + logger->stopWork(); + to << paths; + break; + } + + case wopQueryPathInfo: { + Path path = readStorePath(*store, from); + std::shared_ptr<const ValidPathInfo> info; + logger->startWork(); + try { + info = store->queryPathInfo(path); + } catch (InvalidPath&) { + if (GET_PROTOCOL_MINOR(clientVersion) < 17) { + throw; + } + } + logger->stopWork(); + if (info) { + if (GET_PROTOCOL_MINOR(clientVersion) >= 17) { + to << 1; + } + to << info->deriver << info->narHash.to_string(Base16, false) + << info->references << info->registrationTime << info->narSize; + if (GET_PROTOCOL_MINOR(clientVersion) >= 16) { + to << static_cast<uint64_t>(info->ultimate) << info->sigs << info->ca; + } + } else { + assert(GET_PROTOCOL_MINOR(clientVersion) >= 17); + to << 0; + } + break; + } + + case wopOptimiseStore: { + logger->startWork(); + store->optimiseStore(); + logger->stopWork(); + to << 1; + break; + } + + case wopVerifyStore: { + bool checkContents; + bool repair; + from >> checkContents >> repair; + logger->startWork(); + if (repair && !trusted) { + throw Error("you are not privileged to repair paths"); + } + bool errors = store->verifyStore(checkContents, (RepairFlag)repair); + logger->stopWork(); + to << static_cast<uint64_t>(errors); + break; + } + + case wopAddSignatures: { + Path path = readStorePath(*store, from); + auto sigs = readStrings<StringSet>(from); + logger->startWork(); + if (!trusted) { + throw Error("you are not privileged to add signatures"); + } + store->addSignatures(path, sigs); + logger->stopWork(); + to << 1; + break; + } + + case wopNarFromPath: { + auto path = readStorePath(*store, from); + logger->startWork(); + logger->stopWork(); + dumpPath(path, to); + break; + } + + case wopAddToStoreNar: { + bool repair; + bool dontCheckSigs; + ValidPathInfo info; + info.path = readStorePath(*store, from); + from >> info.deriver; + if (!info.deriver.empty()) { + store->assertStorePath(info.deriver); + } + info.narHash = Hash(readString(from), htSHA256); + info.references = readStorePaths<PathSet>(*store, from); + from >> info.registrationTime >> info.narSize >> info.ultimate; + info.sigs = readStrings<StringSet>(from); + from >> info.ca >> repair >> dontCheckSigs; + if (!trusted && dontCheckSigs) { + dontCheckSigs = false; + } + if (!trusted) { + info.ultimate = false; + } + + std::string saved; + std::unique_ptr<Source> source; + if (GET_PROTOCOL_MINOR(clientVersion) >= 21) { + source = std::make_unique<TunnelSource>(from); + } else { + TeeSink tee(from); + parseDump(tee, tee.source); + saved = std::move(*tee.source.data); + source = std::make_unique<StringSource>(saved); + } + + logger->startWork(); + + // FIXME: race if addToStore doesn't read source? + store->addToStore(info, *source, (RepairFlag)repair, + dontCheckSigs ? NoCheckSigs : CheckSigs, nullptr); + + logger->stopWork(); + break; + } + + case wopQueryMissing: { + auto targets = readStorePaths<PathSet>(*store, from); + logger->startWork(); + PathSet willBuild; + PathSet willSubstitute; + PathSet unknown; + unsigned long long downloadSize; + unsigned long long narSize; + store->queryMissing(targets, willBuild, willSubstitute, unknown, + downloadSize, narSize); + logger->stopWork(); + to << willBuild << willSubstitute << unknown << downloadSize << narSize; + break; + } + + default: + throw Error(format("invalid operation %1%") % op); + } +} + +static void processConnection(bool trusted, const std::string& userName, + uid_t userId) { + MonitorFdHup monitor(from.fd); + + /* Exchange the greeting. */ + unsigned int magic = readInt(from); + if (magic != WORKER_MAGIC_1) { + throw Error("protocol mismatch"); + } + to << WORKER_MAGIC_2 << PROTOCOL_VERSION; + to.flush(); + unsigned int clientVersion = readInt(from); + + if (clientVersion < 0x10a) { + throw Error("the Nix client version is too old"); + } + + auto tunnelLogger = new TunnelLogger(clientVersion); + // logger = tunnelLogger; + + unsigned int opCount = 0; + + Finally finally([&]() { + _isInterrupted = false; + DLOG(INFO) << opCount << " operations"; + }); + + if (GET_PROTOCOL_MINOR(clientVersion) >= 14 && (readInt(from) != 0u)) { + setAffinityTo(readInt(from)); + } + + readInt(from); // obsolete reserveSpace + + /* Send startup error messages to the client. */ + tunnelLogger->startWork(); + + try { + /* If we can't accept clientVersion, then throw an error + *here* (not above). */ + +#if 0 + /* Prevent users from doing something very dangerous. */ + if (geteuid() == 0 && + querySetting("build-users-group", "") == "") + throw Error("if you run 'nix-daemon' as root, then you MUST set 'build-users-group'!"); +#endif + + /* Open the store. */ + Store::Params params; // FIXME: get params from somewhere + // Disable caching since the client already does that. + params["path-info-cache-size"] = "0"; + auto store = openStore(settings.storeUri, params); + + store->createUser(userName, userId); + + tunnelLogger->stopWork(); + to.flush(); + + /* Process client requests. */ + while (true) { + WorkerOp op; + try { + op = (WorkerOp)readInt(from); + } catch (Interrupted& e) { + break; + } catch (EndOfFile& e) { + break; + } + + opCount++; + + try { + performOp(tunnelLogger, store, trusted, clientVersion, from, to, op); + } catch (Error& e) { + /* If we're not in a state where we can send replies, then + something went wrong processing the input of the + client. This can happen especially if I/O errors occur + during addTextToStore() / importPath(). If that + happens, just send the error message and exit. */ + bool errorAllowed = tunnelLogger->state_.lock()->canSendStderr; + tunnelLogger->stopWork(false, e.msg(), e.status); + if (!errorAllowed) { + throw; + } + } catch (std::bad_alloc& e) { + tunnelLogger->stopWork(false, "Nix daemon out of memory", 1); + throw; + } + + to.flush(); + + assert(!tunnelLogger->state_.lock()->canSendStderr); + }; + + } catch (std::exception& e) { + tunnelLogger->stopWork(false, e.what(), 1); + to.flush(); + return; + } +} + +static void sigChldHandler(int sigNo) { + // Ensure we don't modify errno of whatever we've interrupted + auto saved_errno = errno; + /* Reap all dead children. */ + while (waitpid(-1, nullptr, WNOHANG) > 0) { + ; + } + errno = saved_errno; +} + +static void setSigChldAction(bool autoReap) { + struct sigaction act; + struct sigaction oact; + act.sa_handler = autoReap ? sigChldHandler : SIG_DFL; + sigfillset(&act.sa_mask); + act.sa_flags = 0; + if (sigaction(SIGCHLD, &act, &oact) != 0) { + throw SysError("setting SIGCHLD handler"); + } +} + +bool matchUser(const std::string& user, const std::string& group, + const Strings& users) { + if (find(users.begin(), users.end(), "*") != users.end()) { + return true; + } + + if (find(users.begin(), users.end(), user) != users.end()) { + return true; + } + + for (auto& i : users) { + if (std::string(i, 0, 1) == "@") { + if (group == std::string(i, 1)) { + return true; + } + struct group* gr = getgrnam(i.c_str() + 1); + if (gr == nullptr) { + continue; + } + for (char** mem = gr->gr_mem; *mem != nullptr; mem++) { + if (user == std::string(*mem)) { + return true; + } + } + } + } + + return false; +} + +struct PeerInfo { + bool pidKnown; + pid_t pid; + bool uidKnown; + uid_t uid; + bool gidKnown; + gid_t gid; +}; + +/* Get the identity of the caller, if possible. */ +static PeerInfo getPeerInfo(int remote) { + PeerInfo peer = {false, 0, false, 0, false, 0}; + +#if defined(SO_PEERCRED) + + ucred cred; + socklen_t credLen = sizeof(cred); + if (getsockopt(remote, SOL_SOCKET, SO_PEERCRED, &cred, &credLen) == -1) { + throw SysError("getting peer credentials"); + } + peer = {true, cred.pid, true, cred.uid, true, cred.gid}; + +#elif defined(LOCAL_PEERCRED) + +#if !defined(SOL_LOCAL) +#define SOL_LOCAL 0 +#endif + + xucred cred; + socklen_t credLen = sizeof(cred); + if (getsockopt(remote, SOL_LOCAL, LOCAL_PEERCRED, &cred, &credLen) == -1) + throw SysError("getting peer credentials"); + peer = {false, 0, true, cred.cr_uid, false, 0}; + +#endif + + return peer; +} + +#define SD_LISTEN_FDS_START 3 + +static void daemonLoop(char** argv) { + if (chdir("/") == -1) { + throw SysError("cannot change current directory"); + } + + /* Get rid of children automatically; don't let them become + zombies. */ + setSigChldAction(true); + + AutoCloseFD fdSocket; + + /* Handle socket-based activation by systemd. */ + if (!getEnv("LISTEN_FDS").empty()) { + if (getEnv("LISTEN_PID") != std::to_string(getpid()) || + getEnv("LISTEN_FDS") != "1") { + throw Error("unexpected systemd environment variables"); + } + fdSocket = SD_LISTEN_FDS_START; + } + + /* Otherwise, create and bind to a Unix domain socket. */ + else { + /* Create and bind to a Unix domain socket. */ + fdSocket = socket(PF_UNIX, SOCK_STREAM, 0); + if (!fdSocket) { + throw SysError("cannot create Unix domain socket"); + } + + std::string socketPath = settings.nixDaemonSocketFile; + + createDirs(dirOf(socketPath)); + + /* Urgh, sockaddr_un allows path names of only 108 characters. + So chdir to the socket directory so that we can pass a + relative path name. */ + if (chdir(dirOf(socketPath).c_str()) == -1) { + throw SysError("cannot change current directory"); + } + Path socketPathRel = "./" + baseNameOf(socketPath); + + struct sockaddr_un addr; + addr.sun_family = AF_UNIX; + strncpy(addr.sun_path, socketPathRel.c_str(), sizeof(addr.sun_path)); + if (addr.sun_path[sizeof(addr.sun_path) - 1] != '\0') { + throw Error(format("socket path '%1%' is too long") % socketPathRel); + } + + unlink(socketPath.c_str()); + + /* Make sure that the socket is created with 0666 permission + (everybody can connect --- provided they have access to the + directory containing the socket). */ + mode_t oldMode = umask(0111); + int res = bind(fdSocket.get(), (struct sockaddr*)&addr, sizeof(addr)); + umask(oldMode); + if (res == -1) { + throw SysError(format("cannot bind to socket '%1%'") % socketPath); + } + + if (chdir("/") == -1) { /* back to the root */ + throw SysError("cannot change current directory"); + } + + if (listen(fdSocket.get(), 5) == -1) { + throw SysError(format("cannot listen on socket '%1%'") % socketPath); + } + } + + closeOnExec(fdSocket.get()); + + /* Loop accepting connections. */ + while (true) { + try { + /* Accept a connection. */ + struct sockaddr_un remoteAddr; + socklen_t remoteAddrLen = sizeof(remoteAddr); + + AutoCloseFD remote = + accept(fdSocket.get(), (struct sockaddr*)&remoteAddr, &remoteAddrLen); + checkInterrupt(); + if (!remote) { + if (errno == EINTR) { + continue; + } + throw SysError("accepting connection"); + } + + closeOnExec(remote.get()); + + bool trusted = false; + PeerInfo peer = getPeerInfo(remote.get()); + + struct passwd* pw = peer.uidKnown ? getpwuid(peer.uid) : nullptr; + std::string user = pw != nullptr ? pw->pw_name : std::to_string(peer.uid); + + struct group* gr = peer.gidKnown ? getgrgid(peer.gid) : nullptr; + std::string group = + gr != nullptr ? gr->gr_name : std::to_string(peer.gid); + + Strings trustedUsers = settings.trustedUsers; + Strings allowedUsers = settings.allowedUsers; + + if (matchUser(user, group, trustedUsers)) { + trusted = true; + } + + if ((!trusted && !matchUser(user, group, allowedUsers)) || + group == settings.buildUsersGroup) { + throw Error( + format("user '%1%' is not allowed to connect to the Nix daemon") % + user); + } + + LOG(INFO) << "accepted connection from pid " + << (peer.pidKnown ? std::to_string(peer.pid) : "<unknown>") + << ", user " << (peer.uidKnown ? user : "<unknown>") + << (trusted ? " (trusted)" : ""); + + /* Fork a child to handle the connection. */ + ProcessOptions options; + options.errorPrefix = "unexpected Nix daemon error: "; + options.dieWithParent = false; + options.runExitHandlers = true; + startProcess( + [&]() { + fdSocket = -1; + + /* Background the daemon. */ + if (setsid() == -1) { + throw SysError(format("creating a new session")); + } + + /* Restore normal handling of SIGCHLD. */ + setSigChldAction(false); + + /* For debugging, stuff the pid into argv[1]. */ + if (peer.pidKnown && (argv[1] != nullptr)) { + std::string processName = std::to_string(peer.pid); + strncpy(argv[1], processName.c_str(), strlen(argv[1])); + } + + /* Handle the connection. */ + from.fd = remote.get(); + to.fd = remote.get(); + processConnection(trusted, user, peer.uid); + + exit(0); + }, + options); + + } catch (Interrupted& e) { + return; + } catch (Error& e) { + LOG(ERROR) << "error processing connection: " << e.msg(); + } + } +} + +static int _main(int argc, char** argv) { + { + auto stdio = false; + + parseCmdLine(argc, argv, + [&](Strings::iterator& arg, const Strings::iterator& end) { + if (*arg == "--daemon") { + ; /* ignored for backwards compatibility */ + } else if (*arg == "--help") { + showManPage("nix-daemon"); + } else if (*arg == "--version") { + printVersion("nix-daemon"); + } else if (*arg == "--stdio") { + stdio = true; + } else { + return false; + } + return true; + }); + + if (stdio) { + if (getStoreType() == tDaemon) { + /* Forward on this connection to the real daemon */ + auto socketPath = settings.nixDaemonSocketFile; + auto s = socket(PF_UNIX, SOCK_STREAM, 0); + if (s == -1) { + throw SysError("creating Unix domain socket"); + } + + auto socketDir = dirOf(socketPath); + if (chdir(socketDir.c_str()) == -1) { + throw SysError(format("changing to socket directory '%1%'") % + socketDir); + } + + auto socketName = baseNameOf(socketPath); + auto addr = sockaddr_un{}; + addr.sun_family = AF_UNIX; + strncpy(addr.sun_path, socketName.c_str(), sizeof(addr.sun_path)); + if (addr.sun_path[sizeof(addr.sun_path) - 1] != '\0') { + throw Error(format("socket name %1% is too long") % socketName); + } + + if (connect(s, (struct sockaddr*)&addr, sizeof(addr)) == -1) { + throw SysError(format("cannot connect to daemon at %1%") % + socketPath); + } + + auto nfds = (s > STDIN_FILENO ? s : STDIN_FILENO) + 1; + while (true) { + fd_set fds; + FD_ZERO(&fds); + FD_SET(s, &fds); + FD_SET(STDIN_FILENO, &fds); + if (select(nfds, &fds, nullptr, nullptr, nullptr) == -1) { + throw SysError("waiting for data from client or server"); + } + if (FD_ISSET(s, &fds)) { + auto res = splice(s, nullptr, STDOUT_FILENO, nullptr, SSIZE_MAX, + SPLICE_F_MOVE); + if (res == -1) { + throw SysError("splicing data from daemon socket to stdout"); + } + if (res == 0) { + throw EndOfFile("unexpected EOF from daemon socket"); + } + } + if (FD_ISSET(STDIN_FILENO, &fds)) { + auto res = splice(STDIN_FILENO, nullptr, s, nullptr, SSIZE_MAX, + SPLICE_F_MOVE); + if (res == -1) { + throw SysError("splicing data from stdin to daemon socket"); + } + if (res == 0) { + return 0; + } + } + } + } else { + processConnection(true, "root", 0); + } + } else { + daemonLoop(argv); + } + + return 0; + } +} + +static RegisterLegacyCommand s1("nix-daemon", _main); |