From 240f1614d816dc504a6684a7d73618322d589f5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophane=20Hufschmitt?=
 <theophane.hufschmitt@tweag.io>
Date: Mon, 11 Apr 2022 10:20:37 +0200
Subject: [PATCH] Add a proper nix option for the external GC

---
 src/libstore/gc.cc      | 5 +++--
 src/libstore/globals.hh | 7 +++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index 104405d6e..98a7866a1 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -269,8 +269,9 @@ void LocalStore::findRootsNoTemp(Roots & roots, bool censor)
         throw SysError("cannot create Unix domain socket");
     closeOnExec(fd.get());
 
-    // FIXME: Don’t hardcode
-    string socketPath = getEnv("NIX_GC_SOCKET_PATH").value_or("/nix/var/nix/gc-socket/socket");
+    std::string socketPath = settings.gcSocketPath.get() != "auto"
+        ? settings.gcSocketPath.get()
+        : stateDir.get() + gcSocketPath;
 
     struct sockaddr_un addr;
     addr.sun_family = AF_UNIX;
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index feb6899cd..d8db8be76 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -94,6 +94,13 @@ public:
     Setting<std::string> storeUri{this, getEnv("NIX_REMOTE").value_or("auto"), "store",
         "The default Nix store to use."};
 
+    Setting<std::string> gcSocketPath {
+        this,
+        getEnv("NIX_GC_SOCKET_PATH").value_or("auto"),
+        "gc-socket-path",
+        "Path to the socket used to communicate with an external GC."
+    };
+
     Setting<bool> keepFailed{this, false, "keep-failed",
         "Whether to keep temporary directories of failed builds."};