* Pass various options to the worker so that flags like -K or -j work

  in multi-user Nix (NIX-72).
* Client/worker: exchange a protocol version number for future
  compatibility.

3 files changed, 29 insertions, 4 deletions

diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index c5d13bf49495..4d866071b181 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -53,18 +53,24 @@ RemoteStore::RemoteStore()
     from.fd = fdSocket;
     to.fd = fdSocket;
 
-    
     /* Send the magic greeting, check for the reply. */
     try {
         writeInt(WORKER_MAGIC_1, to);
-        writeInt(verbosity, to);
         unsigned int magic = readInt(from);
         if (magic != WORKER_MAGIC_2) throw Error("protocol mismatch");
+
+        unsigned int daemonVersion = readInt(from);
+        if (GET_PROTOCOL_MAJOR(daemonVersion) != GET_PROTOCOL_MAJOR(PROTOCOL_VERSION))
+            throw Error("Nix daemon protocol version not supported");
+        writeInt(PROTOCOL_VERSION, to);
         processStderr();
+
     } catch (Error & e) {
         throw Error(format("cannot start worker (%1%)")
             % e.msg());
     }
+
+    setOptions();
 }
 
 
@@ -154,6 +160,19 @@ RemoteStore::~RemoteStore()
 }
 
 
+void RemoteStore::setOptions()
+{
+    writeInt(wopSetOptions, to);
+    writeInt(keepFailed, to);
+    writeInt(keepGoing, to);
+    writeInt(tryFallback, to);
+    writeInt(verbosity, to);
+    writeInt(maxBuildJobs, to);
+    writeInt(maxSilentTime, to);
+    processStderr();
+}
+
+
 bool RemoteStore::isValidPath(const Path & path)
 {
     writeInt(wopIsValidPath, to);
diff --git a/src/libstore/remote-store.hh b/src/libstore/remote-store.hh
index 87850c406873..79a15e11ef9d 100644
--- a/src/libstore/remote-store.hh
+++ b/src/libstore/remote-store.hh
@@ -77,6 +77,8 @@ private:
     void forkSlave();
     
     void connectToDaemon();
+
+    void setOptions();
 };
 
 
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index f3b63151dbfb..22f5973a96ee 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -5,8 +5,11 @@
 namespace nix {
 
 
-#define WORKER_MAGIC_1 0x6e697864
-#define WORKER_MAGIC_2 0x6478696e
+#define WORKER_MAGIC_1 0x6e697863
+#define WORKER_MAGIC_2 0x6478696f
+
+#define PROTOCOL_VERSION 0x101
+#define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
 
 
 typedef enum {
@@ -28,6 +31,7 @@ typedef enum {
     wopExportPath,
     wopImportPath,
     wopQueryDeriver,
+    wopSetOptions,
 } WorkerOp;