move EvalState into worker to avoid stack-use-after-return

Author: Mic92

src/nix-eval-jobs.cc

@@ -60,9 +60,8 @@ namespace {
 MyArgs myArgs; // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 }
 
-using Processor = std::function<void(
-    nix::ref<nix::EvalState> state, nix::Bindings &autoArgs,
-    nix::AutoCloseFD &to, nix::AutoCloseFD &from, MyArgs &args)>;
+using Processor = std::function<void(MyArgs &myArgs, nix::AutoCloseFD &to,
+                                     nix::AutoCloseFD &from)>;
 
 /* Auto-cleanup of fork's process and fds. */
 struct Proc {
@@ -89,15 +88,7 @@ struct Proc {
                     nix::lvlDebug,
                     nix::fmt("created worker process %d", getpid()));
                 try {
-                    auto evalStore = myArgs.evalStoreUrl
-                                         ? nix::openStore(*myArgs.evalStoreUrl)
-                                         : nix::openStore();
-                    auto state = std::make_shared<nix::EvalState>(
-                        myArgs.lookupPath, evalStore, nix::fetchSettings,
-                        nix::evalSettings);
-                    nix::Bindings &autoArgs = *myArgs.getAutoArgs(*state);
-                    proc(nix::ref<nix::EvalState>(state), autoArgs, *to, *from,
-                         myArgs);
+                    proc(myArgs, *to, *from);
                 } catch (nix::Error &e) {
                     nlohmann::json err;
                     const auto &msg = e.msg();

src/worker.cc

@@ -84,9 +84,16 @@ auto attrPathJoin(nlohmann::json input) -> std::string {
 } // namespace
 
 void worker(
-    nix::ref<nix::EvalState> state, nix::Bindings &autoArgs,
+    MyArgs &args,
     nix::AutoCloseFD &to, // NOLINT(bugprone-easily-swappable-parameters)
-    nix::AutoCloseFD &from, MyArgs &args) {
+    nix::AutoCloseFD &from) {
+
+    auto evalStore = args.evalStoreUrl ? nix::openStore(*args.evalStoreUrl)
+                                       : nix::openStore();
+    auto state = nix::make_ref<nix::EvalState>(
+        args.lookupPath, evalStore, nix::fetchSettings, nix::evalSettings);
+    nix::Bindings &autoArgs = *args.getAutoArgs(*state);
+
     nix::Value *vRoot = [&]() {
         if (args.flake) {
             auto [flakeRef, fragment, outputSpec] =

src/worker.hh

@@ -12,5 +12,4 @@ class EvalState;
 template <typename T> class ref;
 } // namespace nix
 
-void worker(nix::ref<nix::EvalState> state, nix::Bindings &autoArgs,
-            nix::AutoCloseFD &to, nix::AutoCloseFD &from, MyArgs &args);
+void worker(MyArgs &args, nix::AutoCloseFD &to, nix::AutoCloseFD &from);