Build the build hook (remote building) for Windows

maintainers/flake-module.nix

@@ -229,7 +229,7 @@
             ''^src/libstore/build/entry-points\.cc$''
             ''^src/libstore/build/goal\.cc$''
             ''^src/libstore/build/goal\.hh$''
-            ''^src/libstore/unix/build/hook-instance\.cc$''
+            ''^src/libstore/build/hook-instance\.cc$''
             ''^src/libstore/unix/build/local-derivation-goal\.cc$''
             ''^src/libstore/unix/build/local-derivation-goal\.hh$''
             ''^src/libstore/build/substitution-goal\.cc$''

src/libstore/unix/build/child.cc → src/libstore/build/child.cc

@@ -11,6 +11,7 @@ void commonChildInit()
 {
     logger = makeSimpleLogger();
 
+#ifndef _WIN32
     const static std::string pathNullDevice = "/dev/null";
     restoreProcessContext(false);
 
@@ -32,6 +33,7 @@ void commonChildInit()
     if (dup2(fdDevNull, STDIN_FILENO) == -1)
         throw SysError("cannot dup null device into stdin");
     close(fdDevNull);
+#endif
 }
 
 }

src/libstore/build/derivation-goal.cc

@@ -1,7 +1,5 @@
 #include "derivation-goal.hh"
-#ifndef _WIN32 // TODO enable build hook on Windows
-#  include "hook-instance.hh"
-#endif
+#include "hook-instance.hh"
 #include "processes.hh"
 #include "config-global.hh"
 #include "worker.hh"
@@ -106,9 +104,7 @@ std::string DerivationGoal::key()
 
 void DerivationGoal::killChild()
 {
-#ifndef _WIN32 // TODO enable build hook on Windows
     hook.reset();
-#endif
 }
 
 
@@ -632,17 +628,9 @@ void DerivationGoal::started()
         buildMode == bmCheck ? "checking outputs of '%s'" :
         "building '%s'", worker.store.printStorePath(drvPath));
     fmt("building '%s'", worker.store.printStorePath(drvPath));
-#ifndef _WIN32 // TODO enable build hook on Windows
     if (hook) msg += fmt(" on '%s'", machineName);
-#endif
     act = std::make_unique<Activity>(*logger, lvlInfo, actBuild, msg,
-        Logger::Fields{worker.store.printStorePath(drvPath),
-#ifndef _WIN32 // TODO enable build hook on Windows
-        hook ? machineName :
-#endif
-            "",
-        1,
-        1});
+        Logger::Fields{worker.store.printStorePath(drvPath), hook ? machineName : "", 1, 1});
     mcRunningBuilds = std::make_unique<MaintainCount<uint64_t>>(worker.runningBuilds);
     worker.updateProgress();
 }
@@ -825,20 +813,14 @@ void replaceValidPath(const Path & storePath, const Path & tmpPath)
 
 int DerivationGoal::getChildStatus()
 {
-#ifndef _WIN32 // TODO enable build hook on Windows
     return hook->pid.kill();
-#else
-    return 0;
-#endif
 }
 
 
 void DerivationGoal::closeReadPipes()
 {
-#ifndef _WIN32 // TODO enable build hook on Windows
     hook->builderOut.readSide.close();
     hook->fromHook.readSide.close();
-#endif
 }
 
 
@@ -1127,13 +1109,14 @@ Goal::Co DerivationGoal::resolvedFinished()
 
 HookReply DerivationGoal::tryBuildHook()
 {
-#ifdef _WIN32 // TODO enable build hook on Windows
-    return rpDecline;
-#else
     if (settings.buildHook.get().empty() || !worker.tryBuildHook || !useDerivation) return rpDecline;
 
     if (!worker.hook)
-        worker.hook = std::make_unique<HookInstance>();
+        worker.hook = std::make_unique<HookInstance>(
+#ifdef _WIN32
+            worker.ioport.get()
+#endif
+        );
 
     try {
 
@@ -1229,12 +1212,16 @@ HookReply DerivationGoal::tryBuildHook()
     Path logFile = openLogFile();
 
     std::set<MuxablePipePollState::CommChannel> fds;
+#ifndef _WIN32
     fds.insert(hook->fromHook.readSide.get());
     fds.insert(hook->builderOut.readSide.get());
+#else
+    fds.insert(&hook->fromHook);
+    fds.insert(&hook->builderOut);
+#endif
     worker.childStarted(shared_from_this(), fds, false, false);
 
     return rpAccept;
-#endif
 }
 
 
@@ -1300,11 +1287,7 @@ void DerivationGoal::closeLogFile()
 
 bool DerivationGoal::isReadDesc(Descriptor fd)
 {
-#ifdef _WIN32 // TODO enable build hook on Windows
-    return false;
-#else
     return fd == hook->builderOut.readSide.get();
-#endif
 }
 
 void DerivationGoal::handleChildOutput(Descriptor fd, std::string_view data)
@@ -1339,7 +1322,6 @@ void DerivationGoal::handleChildOutput(Descriptor fd, std::string_view data)
         if (logSink) (*logSink)(data);
     }
 
-#ifndef _WIN32 // TODO enable build hook on Windows
     if (hook && fd == hook->fromHook.readSide.get()) {
         for (auto c : data)
             if (c == '\n') {
@@ -1374,7 +1356,6 @@ void DerivationGoal::handleChildOutput(Descriptor fd, std::string_view data)
             } else
                 currentHookLine += c;
     }
-#endif
 }
 
 

src/libstore/build/derivation-goal.hh

@@ -14,9 +14,7 @@ namespace nix {
 
 using std::map;
 
-#ifndef _WIN32 // TODO enable build hook on Windows
 struct HookInstance;
-#endif
 
 typedef enum {rpAccept, rpDecline, rpPostpone} HookReply;
 
@@ -182,12 +180,10 @@ struct DerivationGoal : public Goal
 
     std::string currentHookLine;
 
-#ifndef _WIN32 // TODO enable build hook on Windows
     /**
      * The build hook.
      */
     std::unique_ptr<HookInstance> hook;
-#endif
 
     /**
      * The sort of derivation we are building.

src/libstore/unix/build/hook-instance.cc → src/libstore/build/hook-instance.cc

@@ -8,7 +8,11 @@
 
 namespace nix {
 
-HookInstance::HookInstance()
+HookInstance::HookInstance(
+#ifdef _WIN32
+    HANDLE ioport
+#endif
+    )
 {
     debug("starting build hook '%s'", concatStringsSep(" ", settings.buildHook.get()));
 
@@ -36,14 +40,23 @@ HookInstance::HookInstance()
     args.push_back(std::to_string(verbosity));
 
     /* Create a pipe to get the output of the child. */
+#ifndef _WIN32
     fromHook.create();
+#else
+    fromHook.createAsyncPipe(ioport);
+#endif
 
     /* Create the communication pipes. */
     toHook.create();
 
     /* Create a pipe to get the output of the builder. */
+#ifndef _WIN32
     builderOut.create();
+#else
+    builderOut.createAsyncPipe(ioport);
+#endif
 
+#ifndef _WIN32
     /* Fork the hook. */
     pid = startProcess([&]() {
 
@@ -73,8 +86,11 @@ HookInstance::HookInstance()
     });
 
     pid.setSeparatePG(true);
-    fromHook.writeSide = -1;
-    toHook.readSide = -1;
+#else
+    throw UnimplementedError("build remote hook not yet implemented on Windows.");
+#endif
+    fromHook.writeSide.close();
+    toHook.readSide.close();
 
     sink = FdSink(toHook.writeSide.get());
     std::map<std::string, Config::SettingInfo> settings;
@@ -88,7 +104,7 @@ HookInstance::HookInstance()
 HookInstance::~HookInstance()
 {
     try {
-        toHook.writeSide = -1;
+        toHook.writeSide.close();
         if (pid != -1) pid.kill();
     } catch (...) {
         ignoreExceptionInDestructor();

src/libstore/unix/build/hook-instance.hh → src/libstore/build/hook-instance.hh

@@ -5,6 +5,10 @@
 #include "serialise.hh"
 #include "processes.hh"
 
+#ifdef _WIN32
+#  include "windows-async-pipe.hh"
+#endif
+
 namespace nix {
 
 struct HookInstance
@@ -17,12 +21,22 @@ struct HookInstance
     /**
      * Pipe for the hook's standard output/error.
      */
-    Pipe fromHook;
+#ifndef _WIN32
+    Pipe
+#else
+    windows::AsyncPipe
+#endif
+        fromHook;
 
     /**
      * Pipe for the builder's standard output/error.
      */
-    Pipe builderOut;
+#ifndef _WIN32
+    Pipe
+#else
+    windows::AsyncPipe
+#endif
+        builderOut;
 
     /**
      * The process ID of the hook.
@@ -33,7 +47,11 @@ struct HookInstance
 
     std::map<ActivityId, Activity> activities;
 
-    HookInstance();
+    HookInstance(
+#ifdef _WIN32
+        HANDLE ioport
+#endif
+        );
 
     ~HookInstance();
 };

src/libstore/build/worker.cc

@@ -6,8 +6,8 @@
 #include "derivation-goal.hh"
 #ifndef _WIN32 // TODO Enable building on Windows
 #  include "local-derivation-goal.hh"
-#  include "hook-instance.hh"
 #endif
+#include "hook-instance.hh"
 #include "signals.hh"
 
 namespace nix {

src/libstore/build/worker.hh

@@ -53,10 +53,8 @@ struct Child
     steady_time_point timeStarted;
 };
 
-#ifndef _WIN32 // TODO Enable building on Windows
 /* Forward definition. */
 struct HookInstance;
-#endif
 
 /**
  * Coordinates one or more realisations and their interdependencies.
@@ -161,9 +159,7 @@ public:
     Store & store;
     Store & evalStore;
 
-#ifndef _WIN32 // TODO Enable building on Windows
     std::unique_ptr<HookInstance> hook;
-#endif
 
     uint64_t expectedBuilds = 0;
     uint64_t doneBuilds = 0;