* Sync with the trunk.

12 files changed, 157 insertions, 74 deletions

diff --git a/src/libstore/Makefile.am b/src/libstore/Makefile.am
index e19256b925ea..39a61233b4a7 100644
--- a/src/libstore/Makefile.am
+++ b/src/libstore/Makefile.am
@@ -15,7 +15,16 @@ libstore_la_LIBADD = ../libutil/libutil.la ../boost/format/libformat.la ${aterm_
 EXTRA_DIST = schema.sql
 
 AM_CXXFLAGS = -Wall \
- ${sqlite_include} -I$(srcdir)/.. -I$(srcdir)/../libutil
+ ${sqlite_include} -I$(srcdir)/.. -I$(srcdir)/../libutil \
+ -DNIX_STORE_DIR=\"$(storedir)\" \
+ -DNIX_DATA_DIR=\"$(datadir)\" \
+ -DNIX_STATE_DIR=\"$(localstatedir)/nix\" \
+ -DNIX_LOG_DIR=\"$(localstatedir)/log/nix\" \
+ -DNIX_CONF_DIR=\"$(sysconfdir)/nix\" \
+ -DNIX_LIBEXEC_DIR=\"$(libexecdir)\" \
+ -DNIX_BIN_DIR=\"$(bindir)\" \
+ -I$(srcdir)/.. -I$(srcdir)/../libutil \
+ -I$(srcdir)/../libstore
 
 local-store.lo: schema.sql.hh
 
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index d12f41d66941..a8ef9b23efaf 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1650,6 +1650,9 @@ void DerivationGoal::startBuilder()
             (format("nixbld:!:%1%:\n")
                 % (buildUser.enabled() ? buildUser.getGID() : getgid())).str());
 
+        /* Create /etc/hosts with localhost entry. */
+        writeFile(chrootRootDir + "/etc/hosts", "127.0.0.1 localhost\n");
+
         /* Bind-mount a user-configurable set of directories from the
            host file system.  The `/dev/pts' directory must be mounted
            separately so that newly-created pseudo-terminals show
@@ -2199,9 +2202,7 @@ void SubstitutionGoal::tryNext()
     if (subs.size() == 0) {
         /* None left.  Terminate this goal and let someone else deal
            with it. */
-        printMsg(lvlError,
-            format("path `%1%' is required, but there is no substituter that can build it")
-            % storePath);
+        debug(format("path `%1%' is required, but there is no substituter that can build it") % storePath);
         amDone(ecFailed);
         return;
     }
@@ -2232,8 +2233,7 @@ void SubstitutionGoal::referencesValid()
     trace("all references realised");
 
     if (nrFailed > 0) {
-        printMsg(lvlError,
-            format("some references of path `%1%' could not be realised") % storePath);
+        debug(format("some references of path `%1%' could not be realised") % storePath);
         amDone(ecFailed);
         return;
     }
@@ -2286,9 +2286,7 @@ void SubstitutionGoal::tryToRun()
         return;
     }
 
-    printMsg(lvlInfo,
-        format("substituting path `%1%' using substituter `%2%'")
-        % storePath % sub);
+    printMsg(lvlInfo, format("fetching path `%1%'...") % storePath);
     
     logPipe.create();
 
@@ -2364,19 +2362,15 @@ void SubstitutionGoal::finished()
     try {
         
         if (!statusOk(status))
-            throw SubstError(format("builder for `%1%' %2%")
+            throw SubstError(format("fetching path `%1%' %2%")
                 % storePath % statusToString(status));
 
         if (!pathExists(storePath))
-            throw SubstError(
-                format("substitute did not produce path `%1%'")
-                % storePath);
+            throw SubstError(format("substitute did not produce path `%1%'") % storePath);
         
     } catch (SubstError & e) {
 
-        printMsg(lvlInfo,
-            format("substitution of path `%1%' using substituter `%2%' failed: %3%")
-            % storePath % sub % e.msg());
+        printMsg(lvlInfo, e.msg());
         
         if (printBuildTrace) {
             printMsg(lvlError, format("@ substituter-failed %1% %2% %3%")
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index 2e9dc88237d1..5c22f1406649 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -1,3 +1,5 @@
+#include "config.h"
+
 #include "globals.hh"
 #include "util.hh"
 
@@ -138,5 +140,33 @@ void reloadSettings()
     settings.clear();
 }
 
+
+void setDefaultsFromEnvironment()
+{
+    /* Setup Nix paths. */
+    nixStore = canonPath(getEnv("NIX_STORE_DIR", getEnv("NIX_STORE", NIX_STORE_DIR)));
+    nixDataDir = canonPath(getEnv("NIX_DATA_DIR", NIX_DATA_DIR));
+    nixLogDir = canonPath(getEnv("NIX_LOG_DIR", NIX_LOG_DIR));
+    nixStateDir = canonPath(getEnv("NIX_STATE_DIR", NIX_STATE_DIR));
+    nixDBPath = getEnv("NIX_DB_DIR", nixStateDir + "/db");
+    nixConfDir = canonPath(getEnv("NIX_CONF_DIR", NIX_CONF_DIR));
+    nixLibexecDir = canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR));
+    nixBinDir = canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR));
+
+    string subs = getEnv("NIX_SUBSTITUTERS", "default");
+    if (subs == "default") {
+        substituters.push_back(nixLibexecDir + "/nix/substituters/copy-from-other-stores.pl");
+        substituters.push_back(nixLibexecDir + "/nix/substituters/download-using-manifests.pl");
+    } else
+        substituters = tokenizeString(subs, ":");
+
+    /* Get some settings from the configuration file. */
+    thisSystem = querySetting("system", SYSTEM);
+    maxBuildJobs = queryIntSetting("build-max-jobs", 1);
+    buildCores = queryIntSetting("build-cores", 1);
+    maxSilentTime = queryIntSetting("build-max-silent-time", 0);
+    buildTimeout = queryIntSetting("build-timeout", 0);
+}
+
  
 }
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 231c1f8508ac..12a9b9ca15c0 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -114,7 +114,9 @@ void overrideSetting(const string & name, const Strings & value);
 
 void reloadSettings();
 
-    
+void setDefaultsFromEnvironment();
+
+
 }
 
 
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 8ca5daa9f171..29817df9d6e8 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -327,10 +327,9 @@ void LocalStore::openDB(bool create)
     if (sqlite3_exec(db, ("pragma synchronous = " + syncMode + ";").c_str(), 0, 0, 0) != SQLITE_OK)
         throwSQLiteError(db, "setting synchronous mode");
 
-    /* Set the SQLite journal mode.  WAL mode is fastest, but doesn't
-       seem entirely stable at the moment (Oct. 2010).  Thus, use
-       truncate mode by default. */
-    string mode = queryBoolSetting("use-sqlite-wal", false) ? "wal" : "truncate";
+    /* Set the SQLite journal mode.  WAL mode is fastest, so it's the
+       default. */
+    string mode = queryBoolSetting("use-sqlite-wal", true) ? "wal" : "truncate";
     string prevMode;
     {
         SQLiteStmt stmt;
@@ -367,7 +366,7 @@ void LocalStore::openDB(bool create)
     stmtRegisterValidPath.create(db,
         "insert into ValidPaths (path, hash, registrationTime, deriver, narSize) values (?, ?, ?, ?, ?);");
     stmtUpdatePathInfo.create(db,
-        "update ValidPaths set narSize = ? where path = ?;");
+        "update ValidPaths set narSize = ?, hash = ? where path = ?;");
     stmtAddReference.create(db,
         "insert or replace into Refs (referrer, reference) values (?, ?);");
     stmtQueryPathInfo.create(db,
@@ -684,7 +683,7 @@ ValidPathInfo LocalStore::queryPathInfo(const Path & path)
 }
 
 
-/* Update path info in the database.  Currently only updated the
+/* Update path info in the database.  Currently only updates the
    narSize field. */
 void LocalStore::updatePathInfo(const ValidPathInfo & info)
 {
@@ -693,6 +692,7 @@ void LocalStore::updatePathInfo(const ValidPathInfo & info)
         stmtUpdatePathInfo.bind64(info.narSize);
     else
         stmtUpdatePathInfo.bind(); // null
+    stmtUpdatePathInfo.bind("sha256:" + printHash(info.hash));
     stmtUpdatePathInfo.bind(info.path);
     if (sqlite3_step(stmtUpdatePathInfo) != SQLITE_DONE)
         throwSQLiteError(db, format("updating info of path `%1%' in database") % info.path);
@@ -1125,16 +1125,14 @@ struct HashAndWriteSink : Sink
     HashAndWriteSink(Sink & writeSink) : writeSink(writeSink), hashSink(htSHA256)
     {
     }
-    virtual void operator ()
-        (const unsigned char * data, unsigned int len)
+    virtual void operator () (const unsigned char * data, size_t len)
     {
         writeSink(data, len);
         hashSink(data, len);
     }
     Hash currentHash()
     {
-        HashSink hashSinkClone(hashSink);
-        return hashSinkClone.finish().first;
+        return hashSink.currentHash().first;
     }
 };
 
@@ -1180,7 +1178,7 @@ void LocalStore::exportPath(const Path & path, bool sign,
     
     PathSet references;
     queryReferences(path, references);
-    writeStringSet(references, hashAndWriteSink);
+    writeStrings(references, hashAndWriteSink);
 
     Path deriver = queryDeriver(path);
     writeString(deriver, hashAndWriteSink);
@@ -1223,11 +1221,11 @@ struct HashAndReadSource : Source
     {
         hashing = true;
     }
-    virtual void operator ()
-        (unsigned char * data, unsigned int len)
+    size_t read(unsigned char * data, size_t len)
     {
-        readSource(data, len);
-        if (hashing) hashSink(data, len);
+        size_t n = readSource.read(data, len);
+        if (hashing) hashSink(data, n);
+        return n;
     }
 };
 
@@ -1267,7 +1265,7 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
 
     Path dstPath = readStorePath(hashAndReadSource);
 
-    PathSet references = readStorePaths(hashAndReadSource);
+    PathSet references = readStorePaths<PathSet>(hashAndReadSource);
 
     Path deriver = readString(hashAndReadSource);
     if (deriver != "") assertStorePath(deriver);
@@ -1278,7 +1276,7 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
     bool haveSignature = readInt(hashAndReadSource) == 1;
 
     if (requireSignature && !haveSignature)
-        throw Error("imported archive lacks a signature");
+        throw Error(format("imported archive of `%1%' lacks a signature") % dstPath);
     
     if (haveSignature) {
         string signature = readString(hashAndReadSource);
@@ -1354,6 +1352,19 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
 }
 
 
+Paths LocalStore::importPaths(bool requireSignature, Source & source)
+{
+    Paths res;
+    while (true) {
+        unsigned long long n = readLongLong(source);
+        if (n == 0) break;
+        if (n != 1) throw Error("input doesn't look like something created by `nix-store --export'");
+        res.push_back(importPath(requireSignature, source));
+    }
+    return res;
+}
+
+
 void LocalStore::deleteFromStore(const Path & path, unsigned long long & bytesFreed,
     unsigned long long & blocksFreed)
 {
@@ -1369,7 +1380,7 @@ void LocalStore::deleteFromStore(const Path & path, unsigned long long & bytesFr
                 PathSet referrers; queryReferrers(path, referrers);
                 referrers.erase(path); /* ignore self-references */
                 if (!referrers.empty())
-                    throw PathInUse(format("cannot delete path `%1%' because it is in use by `%2%'")
+                    throw PathInUse(format("cannot delete path `%1%' because it is in use by %2%")
                         % path % showPaths(referrers));
                 invalidatePath(path);
             }
@@ -1409,6 +1420,8 @@ void LocalStore::verifyStore(bool checkContents)
     if (checkContents) {
         printMsg(lvlInfo, "checking hashes...");
 
+        Hash nullHash(htSHA256);
+
         foreach (PathSet::iterator, i, validPaths) {
             try {
                 ValidPathInfo info = queryPathInfo(*i);
@@ -1417,17 +1430,30 @@ void LocalStore::verifyStore(bool checkContents)
                 printMsg(lvlTalkative, format("checking contents of `%1%'") % *i);
                 HashResult current = hashPath(info.hash.type, *i);
                 
-                if (current.first != info.hash) {
+                if (info.hash != nullHash && info.hash != current.first) {
                     printMsg(lvlError, format("path `%1%' was modified! "
                             "expected hash `%2%', got `%3%'")
                         % *i % printHash(info.hash) % printHash(current.first));
                 } else {
+
+                    bool update = false;
+
+                    /* Fill in missing hashes. */
+                    if (info.hash == nullHash) {
+                        printMsg(lvlError, format("fixing missing hash on `%1%'") % *i);
+                        info.hash = current.first;
+                        update = true;
+                    }
+                    
                     /* Fill in missing narSize fields (from old stores). */
                     if (info.narSize == 0) {
                         printMsg(lvlError, format("updating size field on `%1%' to %2%") % *i % current.second);
                         info.narSize = current.second;
-                        updatePathInfo(info);
+                        update = true;                        
                     }
+
+                    if (update) updatePathInfo(info);
+
                 }
             
             } catch (Error & e) {
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index b97e2f406190..2739c4eea69d 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -148,7 +148,7 @@ public:
     void exportPath(const Path & path, bool sign,
         Sink & sink);
 
-    Path importPath(bool requireSignature, Source & source);
+    Paths importPaths(bool requireSignature, Source & source);
     
     void buildDerivations(const PathSet & drvPaths);
 
@@ -261,6 +261,8 @@ private:
 
     Path createTempDirInStore();
 
+    Path importPath(bool requireSignature, Source & source);
+    
     void checkDerivationOutputs(const Path & drvPath, const Derivation & drv);
 };
 
diff --git a/src/libstore/references.cc b/src/libstore/references.cc
index ade9c9aa20e3..c1f9e3ba7711 100644
--- a/src/libstore/references.cc
+++ b/src/libstore/references.cc
@@ -57,11 +57,11 @@ struct RefScanSink : Sink
 
     RefScanSink() : hashSink(htSHA256) { }
     
-    void operator () (const unsigned char * data, unsigned int len);
+    void operator () (const unsigned char * data, size_t len);
 };
 
 
-void RefScanSink::operator () (const unsigned char * data, unsigned int len)
+void RefScanSink::operator () (const unsigned char * data, size_t len)
 {
     hashSink(data, len);
 
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 84c87246f0f0..ce99c205e7d0 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -27,13 +27,15 @@ Path readStorePath(Source & from)
 }
 
 
-PathSet readStorePaths(Source & from)
+template<class T> T readStorePaths(Source & from)
 {
-    PathSet paths = readStringSet(from);
-    foreach (PathSet::iterator, i, paths) assertStorePath(*i);
+    T paths = readStrings<T>(from);
+    foreach (typename T::iterator, i, paths) assertStorePath(*i);
     return paths;
 }
 
+template PathSet readStorePaths(Source & from);
+
 
 RemoteStore::RemoteStore()
 {
@@ -65,6 +67,7 @@ void RemoteStore::openConnection()
     /* Send the magic greeting, check for the reply. */
     try {
         writeInt(WORKER_MAGIC_1, to);
+        to.flush();
         unsigned int magic = readInt(from);
         if (magic != WORKER_MAGIC_2) throw Error("protocol mismatch");
 
@@ -166,6 +169,7 @@ void RemoteStore::connectToDaemon()
 RemoteStore::~RemoteStore()
 {
     try {
+        to.flush();
         fdSocket.close();
         if (child != -1)
             child.wait(true);
@@ -213,7 +217,7 @@ PathSet RemoteStore::queryValidPaths()
     openConnection();
     writeInt(wopQueryValidPaths, to);
     processStderr();
-    return readStorePaths(from);
+    return readStorePaths<PathSet>(from);
 }
 
 
@@ -240,7 +244,7 @@ bool RemoteStore::querySubstitutablePathInfo(const Path & path,
     if (reply == 0) return false;
     info.deriver = readString(from);
     if (info.deriver != "") assertStorePath(info.deriver);
-    info.references = readStorePaths(from);
+    info.references = readStorePaths<PathSet>(from);
     info.downloadSize = readLongLong(from);
     info.narSize = GET_PROTOCOL_MINOR(daemonVersion) >= 7 ? readLongLong(from) : 0;
     return true;
@@ -258,7 +262,7 @@ ValidPathInfo RemoteStore::queryPathInfo(const Path & path)
     info.deriver = readString(from);
     if (info.deriver != "") assertStorePath(info.deriver);
     info.hash = parseHash(htSHA256, readString(from));
-    info.references = readStorePaths(from);
+    info.references = readStorePaths<PathSet>(from);
     info.registrationTime = readInt(from);
     info.narSize = readLongLong(from);
     return info;
@@ -283,7 +287,7 @@ void RemoteStore::queryReferences(const Path & path,
     writeInt(wopQueryReferences, to);
     writeString(path, to);
     processStderr();
-    PathSet references2 = readStorePaths(from);
+    PathSet references2 = readStorePaths<PathSet>(from);
     references.insert(references2.begin(), references2.end());
 }
 
@@ -295,7 +299,7 @@ void RemoteStore::queryReferrers(const Path & path,
     writeInt(wopQueryReferrers, to);
     writeString(path, to);
     processStderr();
-    PathSet referrers2 = readStorePaths(from);
+    PathSet referrers2 = readStorePaths<PathSet>(from);
     referrers.insert(referrers2.begin(), referrers2.end());
 }
 
@@ -318,7 +322,7 @@ PathSet RemoteStore::queryDerivationOutputs(const Path & path)
     writeInt(wopQueryDerivationOutputs, to);
     writeString(path, to);
     processStderr();
-    return readStorePaths(from);
+    return readStorePaths<PathSet>(from);
 }
 
 
@@ -338,7 +342,7 @@ Path RemoteStore::addToStore(const Path & _srcPath,
     openConnection();
     
     Path srcPath(absPath(_srcPath));
-    
+
     writeInt(wopAddToStore, to);
     writeString(baseNameOf(srcPath), to);
     /* backwards compatibility hack */
@@ -358,7 +362,7 @@ Path RemoteStore::addTextToStore(const string & name, const string & s,
     writeInt(wopAddTextToStore, to);
     writeString(name, to);
     writeString(s, to);
-    writeStringSet(references, to);
+    writeStrings(references, to);
     
     processStderr();
     return readStorePath(from);
@@ -377,14 +381,14 @@ void RemoteStore::exportPath(const Path & path, bool sign,
 }
 
 
-Path RemoteStore::importPath(bool requireSignature, Source & source)
+Paths RemoteStore::importPaths(bool requireSignature, Source & source)
 {
     openConnection();
-    writeInt(wopImportPath, to);
+    writeInt(wopImportPaths, to);
     /* We ignore requireSignature, since the worker forces it to true
-       anyway. */    
+       anyway. */
     processStderr(0, &source);
-    return readStorePath(from);
+    return readStorePaths<Paths>(from);
 }
 
 
@@ -392,7 +396,7 @@ void RemoteStore::buildDerivations(const PathSet & drvPaths)
 {
     openConnection();
     writeInt(wopBuildDerivations, to);
-    writeStringSet(drvPaths, to);
+    writeStrings(drvPaths, to);
     processStderr();
     readInt(from);
 }
@@ -459,7 +463,7 @@ void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results)
     
     writeInt(wopCollectGarbage, to);
     writeInt(options.action, to);
-    writeStringSet(options.pathsToDelete, to);
+    writeStrings(options.pathsToDelete, to);
     writeInt(options.ignoreLiveness, to);
     writeLongLong(options.maxFreed, to);
     writeInt(options.maxLinks, to);
@@ -471,7 +475,7 @@ void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results)
     
     processStderr();
     
-    results.paths = readStringSet(from);
+    results.paths = readStrings<PathSet>(from);
     results.bytesFreed = readLongLong(from);
     results.blocksFreed = readLongLong(from);
 }
@@ -482,7 +486,7 @@ PathSet RemoteStore::queryFailedPaths()
     openConnection();
     writeInt(wopQueryFailedPaths, to);
     processStderr();
-    return readStorePaths(from);
+    return readStorePaths<PathSet>(from);
 }
 
 
@@ -490,7 +494,7 @@ void RemoteStore::clearFailedPaths(const PathSet & paths)
 {
     openConnection();
     writeInt(wopClearFailedPaths, to);
-    writeStringSet(paths, to);
+    writeStrings(paths, to);
     processStderr();
     readInt(from);
 }
@@ -498,6 +502,7 @@ void RemoteStore::clearFailedPaths(const PathSet & paths)
 
 void RemoteStore::processStderr(Sink * sink, Source * source)
 {
+    to.flush();
     unsigned int msg;
     while ((msg = readInt(from)) == STDERR_NEXT
         || msg == STDERR_READ || msg == STDERR_WRITE) {
@@ -508,11 +513,11 @@ void RemoteStore::processStderr(Sink * sink, Source * source)
         }
         else if (msg == STDERR_READ) {
             if (!source) throw Error("no source");
-            unsigned int len = readInt(from);
+            size_t len = readInt(from);
             unsigned char * buf = new unsigned char[len];
             AutoDeleteArray<unsigned char> d(buf);
-            (*source)(buf, len);
-            writeString(string((const char *) buf, len), to);
+            writeString(buf, source->read(buf, len), to);
+            to.flush();
         }
         else {
             string s = readString(from);
diff --git a/src/libstore/remote-store.hh b/src/libstore/remote-store.hh
index 3be9e315a219..c5853ef53646 100644
--- a/src/libstore/remote-store.hh
+++ b/src/libstore/remote-store.hh
@@ -58,7 +58,7 @@ public:
     void exportPath(const Path & path, bool sign,
         Sink & sink);
 
-    Path importPath(bool requireSignature, Source & source);
+    Paths importPaths(bool requireSignature, Source & source);
     
     void buildDerivations(const PathSet & drvPaths);
 
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index d67ff2c77299..36ade2170876 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -298,6 +298,17 @@ string showPaths(const PathSet & paths)
 }
 
 
+void exportPaths(StoreAPI & store, const Paths & paths,
+    bool sign, Sink & sink)
+{
+    foreach (Paths::const_iterator, i, paths) {
+        writeInt(1, sink);
+        store.exportPath(*i, sign, sink);
+    }
+    writeInt(0, sink);
+}
+
+
 }
 
 
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 0384657498b5..14890f5225ad 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -154,9 +154,7 @@ public:
     
     /* Copy the contents of a path to the store and register the
        validity the resulting path.  The resulting path is returned.
-       If `fixed' is true, then the output of a fixed-output
-       derivation is pre-loaded into the Nix store.  The function
-       object `filter' can be used to exclude files (see
+       The function object `filter' can be used to exclude files (see
        libutil/archive.hh). */
     virtual Path addToStore(const Path & srcPath,
         bool recursive = true, HashType hashAlgo = htSHA256,
@@ -174,9 +172,9 @@ public:
     virtual void exportPath(const Path & path, bool sign,
         Sink & sink) = 0;
 
-    /* Import a NAR dump created by exportPath() into the Nix
-       store. */
-    virtual Path importPath(bool requireSignature, Source & source) = 0;
+    /* Import a sequence of NAR dumps created by exportPaths() into
+       the Nix store. */
+    virtual Paths importPaths(bool requireSignature, Source & source) = 0;
 
     /* Ensure that the output paths of the derivation are valid.  If
        they are already valid, this is a no-op.  Otherwise, validity
@@ -345,6 +343,12 @@ ValidPathInfo decodeValidPathInfo(std::istream & str,
     bool hashGiven = false);
 
 
+/* Export multiple paths in the format expected by ‘nix-store
+   --import’. */
+void exportPaths(StoreAPI & store, const Paths & paths,
+    bool sign, Sink & sink);
+
+
 }
 
 
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index 576e754d2d7a..ef1e0993df28 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -8,7 +8,7 @@ namespace nix {
 #define WORKER_MAGIC_1 0x6e697863
 #define WORKER_MAGIC_2 0x6478696f
 
-#define PROTOCOL_VERSION 0x108
+#define PROTOCOL_VERSION 0x109
 #define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
 #define GET_PROTOCOL_MINOR(x) ((x) & 0x00ff)
 
@@ -29,7 +29,6 @@ typedef enum {
     wopSyncWithGC = 13,
     wopFindRoots = 14,
     wopExportPath = 16,
-    wopImportPath = 17,
     wopQueryDeriver = 18,
     wopSetOptions = 19,
     wopCollectGarbage = 20,
@@ -39,7 +38,8 @@ typedef enum {
     wopQueryFailedPaths = 24,
     wopClearFailedPaths = 25,
     wopQueryPathInfo = 26,
-    wopQueryDerivationOutputNames = 27,
+    wopImportPaths = 27,
+    wopQueryDerivationOutputNames = 28,
 } WorkerOp;
 
 
@@ -59,7 +59,7 @@ typedef enum {
 
 
 Path readStorePath(Source & from);
-PathSet readStorePaths(Source & from);
+template<class T> T readStorePaths(Source & from);
 
     
 }