diff options
Diffstat (limited to 'third_party/nix/src/nix-daemon/nix-daemon.cc')
| -rw-r--r-- | third_party/nix/src/nix-daemon/nix-daemon.cc | 1149 |
1 files changed, 1149 insertions, 0 deletions
diff --git a/third_party/nix/src/nix-daemon/nix-daemon.cc b/third_party/nix/src/nix-daemon/nix-daemon.cc new file mode 100644 index 0000000000..cd18489b0c --- /dev/null +++ b/third_party/nix/src/nix-daemon/nix-daemon.cc @@ -0,0 +1,1149 @@ +#include "shared.hh" +#include "local-store.hh" +#include "util.hh" +#include "serialise.hh" +#include "worker-protocol.hh" +#include "archive.hh" +#include "affinity.hh" +#include "globals.hh" +#include "monitor-fd.hh" +#include "derivations.hh" +#include "finally.hh" +#include "legacy.hh" + +#include <algorithm> + +#include <cstring> +#include <unistd.h> +#include <signal.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/stat.h> +#include <sys/socket.h> +#include <sys/un.h> +#include <errno.h> +#include <pwd.h> +#include <grp.h> +#include <fcntl.h> +#include <limits.h> + +#if __APPLE__ || __FreeBSD__ +#include <sys/ucred.h> +#endif + +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); + + +Sink & operator << (Sink & sink, const Logger::Fields & fields) +{ + sink << fields.size(); + for (auto & f : fields) { + sink << f.type; + if (f.type == Logger::Field::tInt) + sink << f.i; + else if (f.type == Logger::Field::tString) + sink << f.s; + else abort(); + } + return sink; +} + + +/* 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 : public Logger +{ + struct State + { + bool canSendStderr = false; + std::vector<std::string> pendingMsgs; + }; + + Sync<State> state_; + + unsigned int clientVersion; + + 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(Verbosity lvl, const FormatOrString & fs) override + { + if (lvl > verbosity) return; + + 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 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(ActivityId act, Verbosity lvl, ActivityType type, + const std::string & s, const Fields & fields, ActivityId parent) override + { + if (GET_PROTOCOL_MINOR(clientVersion) < 20) { + if (!s.empty()) + log(lvl, s + "..."); + return; + } + + StringSink buf; + buf << STDERR_START_ACTIVITY << act << lvl << type << s << fields << parent; + enqueueMsg(*buf.s); + } + + void stopActivity(ActivityId act) override + { + if (GET_PROTOCOL_MINOR(clientVersion) < 20) return; + StringSink buf; + buf << STDERR_STOP_ACTIVITY << act; + enqueueMsg(*buf.s); + } + + void result(ActivityId act, ResultType type, const Fields & fields) override + { + if (GET_PROTOCOL_MINOR(clientVersion) < 20) return; + StringSink buf; + buf << STDERR_RESULT << act << type << fields; + enqueueMsg(*buf.s); + } +}; + + +struct TunnelSink : Sink +{ + Sink & to; + TunnelSink(Sink & to) : to(to) { } + virtual void operator () (const unsigned char * data, size_t len) + { + to << STDERR_WRITE; + writeString(data, len, to); + } +}; + + +struct TunnelSource : BufferedSource +{ + Source & from; + 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; + string s; + + RetrieveRegularNARSink() : regular(true) { } + + void createDirectory(const Path & path) + { + regular = false; + } + + void receiveContents(unsigned char * data, unsigned int len) + { + s.append((const char *) data, len); + } + + void createSymlink(const Path & path, const string & target) + { + regular = false; + } +}; + + +static void performOp(TunnelLogger * logger, 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 << result; + break; + } + + case wopQueryValidPaths: { + PathSet 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 << (res.find(path) != res.end()); + break; + } + + case wopQuerySubstitutablePaths: { + PathSet 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: { + string hashPart = readString(from); + logger->startWork(); + Path path = store->queryPathFromHashPart(hashPart); + logger->stopWork(); + to << path; + break; + } + + case wopAddToStore: { + bool fixed, recursive; + std::string s, baseName; + from >> baseName >> fixed /* obsolete */ >> recursive >> s; + /* Compatibility hack. */ + if (!fixed) { + s = "sha256"; + recursive = true; + } + HashType hashAlgo = parseHashType(s); + + 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: { + string suffix = readString(from); + string s = readString(from); + PathSet 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: { + PathSet 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); + BuildMode 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); + settings.keepGoing = readInt(from); + settings.tryFallback = readInt(from); + verbosity = (Verbosity) readInt(from); + settings.maxBuildJobs.assign(readInt(from)); + settings.maxSilentTime = readInt(from); + readInt(from); // obsolete useBuildHook + settings.verboseBuild = lvlError == (Verbosity) readInt(from); + readInt(from); // obsolete logType + readInt(from); // obsolete printBuildTrace + settings.buildCores = readInt(from); + settings.useSubstitutes = readInt(from); + + StringMap overrides; + if (GET_PROTOCOL_MINOR(clientVersion) >= 12) { + unsigned int n = readInt(from); + for (unsigned int i = 0; i < n; i++) { + string name = readString(from); + 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; + auto ss = tokenizeString<Strings>(value); + for (auto & s : ss) + if (trusted.count(s)) + subs.push_back(s); + else + warn("ignoring untrusted substituter '%s'", 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 == "")) + settings.set(name, value); + else if (setSubstituters(settings.substituters)) + ; + else if (setSubstituters(settings.extraSubstituters)) + ; + else + warn("ignoring the user-specified setting '%s', because it is a restricted setting and you are not a trusted user", name); + } catch (UsageError & e) { + warn(e.what()); + } + } + + logger->stopWork(); + break; + } + + case wopQuerySubstitutablePathInfo: { + Path path = absPath(readString(from)); + logger->startWork(); + SubstitutablePathInfos infos; + store->querySubstitutablePathInfos({path}, infos); + logger->stopWork(); + SubstitutablePathInfos::iterator 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: { + PathSet 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 << 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, 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 << errors; + break; + } + + case wopAddSignatures: { + Path path = readStorePath(*store, from); + StringSet 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, 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: { + PathSet targets = readStorePaths<PathSet>(*store, from); + logger->startWork(); + PathSet willBuild, willSubstitute, unknown; + unsigned long long downloadSize, 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); + auto prevLogger = nix::logger; + logger = tunnelLogger; + + unsigned int opCount = 0; + + Finally finally([&]() { + _isInterrupted = false; + prevLogger->log(lvlDebug, fmt("%d operations", opCount)); + }); + + if (GET_PROTOCOL_MINOR(clientVersion) >= 14 && readInt(from)) + 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, 0, WNOHANG) > 0) ; + errno = saved_errno; +} + + +static void setSigChldAction(bool autoReap) +{ + struct sigaction act, oact; + act.sa_handler = autoReap ? sigChldHandler : SIG_DFL; + sigfillset(&act.sa_mask); + act.sa_flags = 0; + if (sigaction(SIGCHLD, &act, &oact)) + throw SysError("setting SIGCHLD handler"); +} + + +bool matchUser(const string & user, const 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 (string(i, 0, 1) == "@") { + if (group == string(i, 1)) return true; + struct group * gr = getgrnam(i.c_str() + 1); + if (!gr) continue; + for (char * * mem = gr->gr_mem; *mem; mem++) + if (user == 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") != "") { + 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"); + + 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; + if (socketPathRel.size() >= sizeof(addr.sun_path)) + throw Error(format("socket path '%1%' is too long") % socketPathRel); + strcpy(addr.sun_path, socketPathRel.c_str()); + + 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 (1) { + + 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) : 0; + string user = pw ? pw->pw_name : std::to_string(peer.uid); + + struct group * gr = peer.gidKnown ? getgrgid(peer.gid) : 0; + string group = gr ? 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); + + printInfo(format((string) "accepted connection from pid %1%, user %2%" + (trusted ? " (trusted)" : "")) + % (peer.pidKnown ? std::to_string(peer.pid) : "<unknown>") + % (peer.uidKnown ? user : "<unknown>")); + + /* Fork a child to handle the connection. */ + ProcessOptions options; + options.errorPrefix = "unexpected Nix daemon error: "; + options.dieWithParent = false; + options.runExitHandlers = true; + options.allowVfork = false; + 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]) { + 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) { + printError(format("error processing connection: %1%") % 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; + }); + + initPlugins(); + + 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; + if (socketName.size() + 1 >= sizeof(addr.sun_path)) + throw Error(format("socket name %1% is too long") % socketName); + strcpy(addr.sun_path, socketName.c_str()); + + 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"); + else 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"); + else if (res == 0) + return 0; + } + } + } else { + processConnection(true, "root", 0); + } + } else { + daemonLoop(argv); + } + + return 0; + } +} + +static RegisterLegacyCommand s1("nix-daemon", _main); |