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author | Ludovic Courtès <ludo@gnu.org> | 2014-12-17 23:00:42 +0100 |
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committer | Ludovic Courtès <ludo@gnu.org> | 2014-12-19 22:47:37 +0100 |
commit | 36457566f9917dc7c0c348d012816a2ca333ef1b (patch) | |
tree | 6f1d22a195ea2483b9ce539227d65e8e2a9c137d /nix/nix-daemon | |
parent | 2c7ee1672029aa43afb509af5b5f7261244fa2d1 (diff) | |
download | gnu-guix-36457566f9917dc7c0c348d012816a2ca333ef1b.tar gnu-guix-36457566f9917dc7c0c348d012816a2ca333ef1b.tar.gz |
Merge branch 'nix' into 'master'.
Diffstat (limited to 'nix/nix-daemon')
-rw-r--r-- | nix/nix-daemon/nix-daemon.cc | 939 |
1 files changed, 939 insertions, 0 deletions
diff --git a/nix/nix-daemon/nix-daemon.cc b/nix/nix-daemon/nix-daemon.cc new file mode 100644 index 0000000000..8814fe3155 --- /dev/null +++ b/nix/nix-daemon/nix-daemon.cc @@ -0,0 +1,939 @@ +#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 <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 <fcntl.h> +#include <errno.h> + +using namespace nix; + + +/* On platforms that have O_ASYNC, we can detect when a client + disconnects and immediately kill any ongoing builds. On platforms + that lack it, we only notice the disconnection the next time we try + to write to the client. So if you have a builder that never + generates output on stdout/stderr, the daemon will never notice + that the client has disconnected until the builder terminates. + + GNU/Hurd does have O_ASYNC, but its Unix-domain socket translator + (pflocal) does not implement F_SETOWN. See + <http://lists.gnu.org/archive/html/bug-guix/2013-07/msg00021.html> for + details.*/ +#if defined O_ASYNC && !defined __GNU__ +#define HAVE_HUP_NOTIFICATION +#ifndef SIGPOLL +#define SIGPOLL SIGIO +#endif +#endif + + +static FdSource from(STDIN_FILENO); +static FdSink to(STDOUT_FILENO); + +bool canSendStderr; +pid_t myPid; + + + +/* This function is called anytime we want to write something to + stderr. If we're in a state where the protocol allows it (i.e., + when canSendStderr), send the message to the client over the + socket. */ +static void tunnelStderr(const unsigned char * buf, size_t count) +{ + /* Don't send the message to the client if we're a child of the + process handling the connection. Otherwise we could screw up + the protocol. It's up to the parent to redirect stderr and + send it to the client somehow (e.g., as in build.cc). */ + if (canSendStderr && myPid == getpid()) { + try { + writeInt(STDERR_NEXT, to); + writeString(buf, count, to); + to.flush(); + } catch (...) { + /* Write failed; that means that the other side is + gone. */ + canSendStderr = false; + throw; + } + } else + writeFull(STDERR_FILENO, buf, count); +} + + +/* Return true if the remote side has closed its end of the + connection, false otherwise. Should not be called on any socket on + which we expect input! */ +static bool isFarSideClosed(int socket) +{ + struct timeval timeout; + timeout.tv_sec = timeout.tv_usec = 0; + + fd_set fds; + FD_ZERO(&fds); + FD_SET(socket, &fds); + + while (select(socket + 1, &fds, 0, 0, &timeout) == -1) + if (errno != EINTR) throw SysError("select()"); + + if (!FD_ISSET(socket, &fds)) return false; + + /* Destructive read to determine whether the select() marked the + socket as readable because there is actual input or because + we've reached EOF (i.e., a read of size 0 is available). */ + char c; + int rd; + if ((rd = read(socket, &c, 1)) > 0) + throw Error("EOF expected (protocol error?)"); + else if (rd == -1 && errno != ECONNRESET) + throw SysError("expected connection reset or EOF"); + + return true; +} + + +/* A SIGPOLL signal is received when data is available on the client + communication socket, or when the client has closed its side of the + socket. This handler is enabled at precisely those moments in the + protocol when we're doing work and the client is supposed to be + quiet. Thus, if we get a SIGPOLL signal, it means that the client + has quit. So we should quit as well. + + Too bad most operating systems don't support the POLL_HUP value for + si_code in siginfo_t. That would make most of the SIGPOLL + complexity unnecessary, i.e., we could just enable SIGPOLL all the + time and wouldn't have to worry about races. */ +static void sigPollHandler(int sigNo) +{ + using namespace std; + try { + /* Check that the far side actually closed. We're still + getting spurious signals every once in a while. I.e., + there is no input available, but we get a signal with + POLL_IN set. Maybe it's delayed or something. */ + if (isFarSideClosed(from.fd)) { + if (!blockInt) { + _isInterrupted = 1; + blockInt = 1; + canSendStderr = false; + const char * s = "SIGPOLL\n"; + write(STDERR_FILENO, s, strlen(s)); + } + } else { + const char * s = "spurious SIGPOLL\n"; + write(STDERR_FILENO, s, strlen(s)); + } + } + catch (Error & e) { + /* Shouldn't happen. */ + string s = "impossible: " + e.msg() + '\n'; + write(STDERR_FILENO, s.data(), s.size()); + throw; + } +} + + +static void setSigPollAction(bool enable) +{ +#ifdef HAVE_HUP_NOTIFICATION + struct sigaction act, oact; + act.sa_handler = enable ? sigPollHandler : SIG_IGN; + sigfillset(&act.sa_mask); + act.sa_flags = 0; + if (sigaction(SIGPOLL, &act, &oact)) + throw SysError("setting handler for SIGPOLL"); +#endif +} + + +/* startWork() means that we're starting an operation for which we + want to send out stderr to the client. */ +static void startWork() +{ + canSendStderr = true; + + /* Handle client death asynchronously. */ + setSigPollAction(true); + + /* Of course, there is a race condition here: the socket could + have closed between when we last read from / wrote to it, and + between the time we set the handler for SIGPOLL. In that case + we won't get the signal. So do a non-blocking select() to find + out if any input is available on the socket. If there is, it + has to be the 0-byte read that indicates that the socket has + closed. */ + if (isFarSideClosed(from.fd)) { + _isInterrupted = 1; + checkInterrupt(); + } +} + + +/* stopWork() means that we're done; stop sending stderr to the + client. */ +static void stopWork(bool success = true, const string & msg = "", unsigned int status = 0) +{ + /* Stop handling async client death; we're going to a state where + we're either sending or receiving from the client, so we'll be + notified of client death anyway. */ + setSigPollAction(false); + + canSendStderr = false; + + if (success) + writeInt(STDERR_LAST, to); + else { + writeInt(STDERR_ERROR, to); + writeString(msg, to); + if (status != 0) writeInt(status, to); + } +} + + +struct TunnelSink : Sink +{ + Sink & to; + TunnelSink(Sink & to) : to(to) { } + virtual void operator () (const unsigned char * data, size_t len) + { + writeInt(STDERR_WRITE, to); + writeString(data, len, to); + } +}; + + +struct TunnelSource : BufferedSource +{ + Source & from; + TunnelSource(Source & from) : from(from) { } + size_t readUnbuffered(unsigned char * data, size_t len) + { + /* Careful: we're going to receive data from the client now, + so we have to disable the SIGPOLL handler. */ + setSigPollAction(false); + canSendStderr = false; + + writeInt(STDERR_READ, to); + writeInt(len, to); + to.flush(); + size_t n = readString(data, len, from); + + startWork(); + 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; + } +}; + + +/* Adapter class of a Source that saves all data read to `s'. */ +struct SavingSourceAdapter : Source +{ + Source & orig; + string s; + SavingSourceAdapter(Source & orig) : orig(orig) { } + size_t read(unsigned char * data, size_t len) + { + size_t n = orig.read(data, len); + s.append((const char *) data, n); + return n; + } +}; + + +static void performOp(bool trusted, unsigned int clientVersion, + Source & from, Sink & to, unsigned int op) +{ + switch (op) { + +#if 0 + case wopQuit: { + /* Close the database. */ + store.reset((StoreAPI *) 0); + writeInt(1, to); + break; + } +#endif + + 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); + startWork(); + assertStorePath(path); + bool result = store->isValidPath(path); + stopWork(); + writeInt(result, to); + break; + } + + case wopQueryValidPaths: { + PathSet paths = readStorePaths<PathSet>(from); + startWork(); + PathSet res = store->queryValidPaths(paths); + stopWork(); + writeStrings(res, to); + break; + } + + case wopHasSubstitutes: { + Path path = readStorePath(from); + startWork(); + PathSet res = store->querySubstitutablePaths(singleton<PathSet>(path)); + stopWork(); + writeInt(res.find(path) != res.end(), to); + break; + } + + case wopQuerySubstitutablePaths: { + PathSet paths = readStorePaths<PathSet>(from); + startWork(); + PathSet res = store->querySubstitutablePaths(paths); + stopWork(); + writeStrings(res, to); + break; + } + + case wopQueryPathHash: { + Path path = readStorePath(from); + startWork(); + Hash hash = store->queryPathHash(path); + stopWork(); + writeString(printHash(hash), to); + break; + } + + case wopQueryReferences: + case wopQueryReferrers: + case wopQueryValidDerivers: + case wopQueryDerivationOutputs: { + Path path = readStorePath(from); + startWork(); + PathSet paths; + if (op == wopQueryReferences) + store->queryReferences(path, paths); + else if (op == wopQueryReferrers) + store->queryReferrers(path, paths); + else if (op == wopQueryValidDerivers) + paths = store->queryValidDerivers(path); + else paths = store->queryDerivationOutputs(path); + stopWork(); + writeStrings(paths, to); + break; + } + + case wopQueryDerivationOutputNames: { + Path path = readStorePath(from); + startWork(); + StringSet names; + names = store->queryDerivationOutputNames(path); + stopWork(); + writeStrings(names, to); + break; + } + + case wopQueryDeriver: { + Path path = readStorePath(from); + startWork(); + Path deriver = store->queryDeriver(path); + stopWork(); + writeString(deriver, to); + break; + } + + case wopQueryPathFromHashPart: { + string hashPart = readString(from); + startWork(); + Path path = store->queryPathFromHashPart(hashPart); + stopWork(); + writeString(path, to); + break; + } + + case wopAddToStore: { + string baseName = readString(from); + bool fixed = readInt(from) == 1; /* obsolete */ + bool recursive = readInt(from) == 1; + string s = readString(from); + /* Compatibility hack. */ + if (!fixed) { + s = "sha256"; + recursive = true; + } + HashType hashAlgo = parseHashType(s); + + SavingSourceAdapter 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); + + startWork(); + if (!savedRegular.regular) throw Error("regular file expected"); + Path path = dynamic_cast<LocalStore *>(store.get()) + ->addToStoreFromDump(recursive ? savedNAR.s : savedRegular.s, baseName, recursive, hashAlgo); + stopWork(); + + writeString(path, to); + break; + } + + case wopAddTextToStore: { + string suffix = readString(from); + string s = readString(from); + PathSet refs = readStorePaths<PathSet>(from); + startWork(); + Path path = store->addTextToStore(suffix, s, refs); + stopWork(); + writeString(path, to); + break; + } + + case wopExportPath: { + Path path = readStorePath(from); + bool sign = readInt(from) == 1; + startWork(); + TunnelSink sink(to); + store->exportPath(path, sign, sink); + stopWork(); + writeInt(1, to); + break; + } + + case wopImportPaths: { + startWork(); + TunnelSource source(from); + Paths paths = store->importPaths(true, source); + stopWork(); + writeStrings(paths, to); + break; + } + + case wopBuildPaths: { + PathSet drvs = readStorePaths<PathSet>(from); + startWork(); + store->buildPaths(drvs); + stopWork(); + writeInt(1, to); + break; + } + + case wopEnsurePath: { + Path path = readStorePath(from); + startWork(); + store->ensurePath(path); + stopWork(); + writeInt(1, to); + break; + } + + case wopAddTempRoot: { + Path path = readStorePath(from); + startWork(); + store->addTempRoot(path); + stopWork(); + writeInt(1, to); + break; + } + + case wopAddIndirectRoot: { + Path path = absPath(readString(from)); + startWork(); + store->addIndirectRoot(path); + stopWork(); + writeInt(1, to); + break; + } + + case wopSyncWithGC: { + startWork(); + store->syncWithGC(); + stopWork(); + writeInt(1, to); + break; + } + + case wopFindRoots: { + startWork(); + Roots roots = store->findRoots(); + stopWork(); + writeInt(roots.size(), to); + for (Roots::iterator i = roots.begin(); i != roots.end(); ++i) { + writeString(i->first, to); + writeString(i->second, to); + } + break; + } + + case wopCollectGarbage: { + GCOptions options; + options.action = (GCOptions::GCAction) readInt(from); + options.pathsToDelete = readStorePaths<PathSet>(from); + options.ignoreLiveness = readInt(from); + options.maxFreed = readLongLong(from); + readInt(from); // obsolete field + if (GET_PROTOCOL_MINOR(clientVersion) >= 5) { + /* removed options */ + readInt(from); + readInt(from); + } + + GCResults results; + + startWork(); + if (options.ignoreLiveness) + throw Error("you are not allowed to ignore liveness"); + store->collectGarbage(options, results); + stopWork(); + + writeStrings(results.paths, to); + writeLongLong(results.bytesFreed, to); + writeLongLong(0, to); // obsolete + + break; + } + + case wopSetOptions: { + settings.keepFailed = readInt(from) != 0; + settings.keepGoing = readInt(from) != 0; + settings.set("build-fallback", readInt(from) ? "true" : "false"); + verbosity = (Verbosity) readInt(from); + settings.set("build-max-jobs", int2String(readInt(from))); + settings.set("build-max-silent-time", int2String(readInt(from))); + if (GET_PROTOCOL_MINOR(clientVersion) >= 2) + settings.useBuildHook = readInt(from) != 0; + if (GET_PROTOCOL_MINOR(clientVersion) >= 4) { + settings.buildVerbosity = (Verbosity) readInt(from); + logType = (LogType) readInt(from); + settings.printBuildTrace = readInt(from) != 0; + } + if (GET_PROTOCOL_MINOR(clientVersion) >= 6) + settings.set("build-cores", int2String(readInt(from))); + if (GET_PROTOCOL_MINOR(clientVersion) >= 10) + settings.set("build-use-substitutes", readInt(from) ? "true" : "false"); + 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); + if (name == "build-timeout" || name == "use-ssh-substituter") + settings.set(name, value); + else + settings.set(trusted ? name : "untrusted-" + name, value); + } + } + settings.update(); + startWork(); + stopWork(); + break; + } + + case wopQuerySubstitutablePathInfo: { + Path path = absPath(readString(from)); + startWork(); + SubstitutablePathInfos infos; + store->querySubstitutablePathInfos(singleton<PathSet>(path), infos); + stopWork(); + SubstitutablePathInfos::iterator i = infos.find(path); + if (i == infos.end()) + writeInt(0, to); + else { + writeInt(1, to); + writeString(i->second.deriver, to); + writeStrings(i->second.references, to); + writeLongLong(i->second.downloadSize, to); + if (GET_PROTOCOL_MINOR(clientVersion) >= 7) + writeLongLong(i->second.narSize, to); + } + break; + } + + case wopQuerySubstitutablePathInfos: { + PathSet paths = readStorePaths<PathSet>(from); + startWork(); + SubstitutablePathInfos infos; + store->querySubstitutablePathInfos(paths, infos); + stopWork(); + writeInt(infos.size(), to); + foreach (SubstitutablePathInfos::iterator, i, infos) { + writeString(i->first, to); + writeString(i->second.deriver, to); + writeStrings(i->second.references, to); + writeLongLong(i->second.downloadSize, to); + writeLongLong(i->second.narSize, to); + } + break; + } + + case wopQueryAllValidPaths: { + startWork(); + PathSet paths = store->queryAllValidPaths(); + stopWork(); + writeStrings(paths, to); + break; + } + + case wopQueryFailedPaths: { + startWork(); + PathSet paths = store->queryFailedPaths(); + stopWork(); + writeStrings(paths, to); + break; + } + + case wopClearFailedPaths: { + PathSet paths = readStrings<PathSet>(from); + startWork(); + store->clearFailedPaths(paths); + stopWork(); + writeInt(1, to); + break; + } + + case wopQueryPathInfo: { + Path path = readStorePath(from); + startWork(); + ValidPathInfo info = store->queryPathInfo(path); + stopWork(); + writeString(info.deriver, to); + writeString(printHash(info.hash), to); + writeStrings(info.references, to); + writeInt(info.registrationTime, to); + writeLongLong(info.narSize, to); + break; + } + + default: + throw Error(format("invalid operation %1%") % op); + } +} + + +static void processConnection(bool trusted) +{ + canSendStderr = false; + myPid = getpid(); + _writeToStderr = tunnelStderr; + +#ifdef HAVE_HUP_NOTIFICATION + /* Allow us to receive SIGPOLL for events on the client socket. */ + setSigPollAction(false); + if (fcntl(from.fd, F_SETOWN, getpid()) == -1) + throw SysError("F_SETOWN"); + if (fcntl(from.fd, F_SETFL, fcntl(from.fd, F_GETFL, 0) | O_ASYNC) == -1) + throw SysError("F_SETFL"); +#endif + + /* Exchange the greeting. */ + unsigned int magic = readInt(from); + if (magic != WORKER_MAGIC_1) throw Error("protocol mismatch"); + writeInt(WORKER_MAGIC_2, to); + writeInt(PROTOCOL_VERSION, to); + to.flush(); + unsigned int clientVersion = readInt(from); + + if (GET_PROTOCOL_MINOR(clientVersion) >= 14 && readInt(from)) + setAffinityTo(readInt(from)); + + bool reserveSpace = true; + if (GET_PROTOCOL_MINOR(clientVersion) >= 11) + reserveSpace = readInt(from) != 0; + + /* Send startup error messages to the client. */ + 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 = std::shared_ptr<StoreAPI>(new LocalStore(reserveSpace)); + + stopWork(); + to.flush(); + + } catch (Error & e) { + stopWork(false, e.msg()); + to.flush(); + return; + } + + /* Process client requests. */ + unsigned int opCount = 0; + + while (true) { + WorkerOp op; + try { + op = (WorkerOp) readInt(from); + } catch (EndOfFile & e) { + break; + } + + opCount++; + + try { + performOp(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 = canSendStderr; + if (!errorAllowed) printMsg(lvlError, format("error processing client input: %1%") % e.msg()); + stopWork(false, e.msg(), GET_PROTOCOL_MINOR(clientVersion) >= 8 ? e.status : 0); + if (!errorAllowed) break; + } catch (std::bad_alloc & e) { + if (canSendStderr) + stopWork(false, "Nix daemon out of memory", GET_PROTOCOL_MINOR(clientVersion) >= 8 ? 1 : 0); + throw; + } + + to.flush(); + + assert(!canSendStderr); + }; + + printMsg(lvlError, format("%1% operations") % opCount); +} + + +static void sigChldHandler(int sigNo) +{ + /* Reap all dead children. */ + while (waitpid(-1, 0, WNOHANG) > 0) ; +} + + +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"); +} + + +#define SD_LISTEN_FDS_START 3 + + +static void daemonLoop() +{ + /* 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") != int2String(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 == -1) + 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. */ + chdir(dirOf(socketPath).c_str()); + 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, (struct sockaddr *) &addr, sizeof(addr)); + umask(oldMode); + if (res == -1) + throw SysError(format("cannot bind to socket `%1%'") % socketPath); + + chdir("/"); /* back to the root */ + + if (listen(fdSocket, 5) == -1) + throw SysError(format("cannot listen on socket `%1%'") % socketPath); + } + + closeOnExec(fdSocket); + + /* Loop accepting connections. */ + while (1) { + + try { + /* Important: the server process *cannot* open the SQLite + database, because it doesn't like forks very much. */ + assert(!store); + + /* Accept a connection. */ + struct sockaddr_un remoteAddr; + socklen_t remoteAddrLen = sizeof(remoteAddr); + + AutoCloseFD remote = accept(fdSocket, + (struct sockaddr *) &remoteAddr, &remoteAddrLen); + checkInterrupt(); + if (remote == -1) { + if (errno == EINTR) + continue; + else + throw SysError("accepting connection"); + } + + closeOnExec(remote); + + /* Get the identity of the caller, if possible. */ + uid_t clientUid = -1; + pid_t clientPid = -1; + bool trusted = false; + +#if defined(SO_PEERCRED) + ucred cred; + socklen_t credLen = sizeof(cred); + if (getsockopt(remote, SOL_SOCKET, SO_PEERCRED, &cred, &credLen) != -1) { + clientPid = cred.pid; + clientUid = cred.uid; + if (clientUid == 0) trusted = true; + } +#endif + + printMsg(lvlInfo, format("accepted connection from pid %1%, uid %2%") % clientPid % clientUid); + + /* Fork a child to handle the connection. */ + pid_t child; + child = fork(); + + switch (child) { + + case -1: + throw SysError("unable to fork"); + + case 0: + try { /* child */ + + /* 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 (clientPid != -1 && argvSaved[1]) { + string processName = int2String(clientPid); + strncpy(argvSaved[1], processName.c_str(), strlen(argvSaved[1])); + } + + /* Handle the connection. */ + from.fd = remote; + to.fd = remote; + processConnection(trusted); + + } catch (std::exception & e) { + writeToStderr("unexpected Nix daemon error: " + string(e.what()) + "\n"); + } + exit(0); + } + + } catch (Interrupted & e) { + throw; + } catch (Error & e) { + printMsg(lvlError, format("error processing connection: %1%") % e.msg()); + } + } +} + + +void run(Strings args) +{ + for (Strings::iterator i = args.begin(); i != args.end(); ) { + string arg = *i++; + if (arg == "--daemon") /* ignored for backwards compatibility */; + } + + chdir("/"); + daemonLoop(); +} + + +void printHelp() +{ + showManPage("nix-daemon"); +} + + +string programId = "nix-daemon"; |