From 2a9fddc0b16d9b4771d11fc10d8b2a9cba55ff64 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 23 Jun 2022 16:29:50 +0200
Subject: [PATCH 1/3] Automatically use a chroot store if /nix doesn't exist

Specifically, if we're not root and the daemon socket does not exist,
then we use ~/.local/share/nix/root as a chroot store. This enables
non-root users to download nix-static and have it work out of the box,
e.g.

  ubuntu@ip-10-13-1-146:~$ ~/nix run nixpkgs#hello
  warning: '/nix' does not exists, so Nix will use '/home/ubuntu/.local/share/nix/root' as a chroot store
  Hello, world!
---
 src/libstore/store-api.cc | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 8861274a2..b46b3066b 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -1302,7 +1302,8 @@ std::pair<std::string, Store::Params> splitUriAndParams(const std::string & uri_
     return {uri, params};
 }
 
-static bool isNonUriPath(const std::string & spec) {
+static bool isNonUriPath(const std::string & spec)
+{
     return
         // is not a URL
         spec.find("://") == std::string::npos
@@ -1319,7 +1320,19 @@ std::shared_ptr<Store> openFromNonUri(const std::string & uri, const Store::Para
             return std::make_shared<LocalStore>(params);
         else if (pathExists(settings.nixDaemonSocketFile))
             return std::make_shared<UDSRemoteStore>(params);
-        else
+        else if (!pathExists(stateDir) && params.empty() && getuid() != 0) {
+            /* If /nix doesn't exist, there is no daemon socket, and
+               we're not root, then automatically set up a chroot
+               store in ~/.local/share/nix/root. */
+            auto chrootStore = getDataDir() + "/nix/root";
+            if (!pathExists(chrootStore))
+                warn("'/nix' does not exists, so Nix will use '%s' as a chroot store", chrootStore);
+            else
+                debug("'/nix' does not exists, so Nix will use '%s' as a chroot store", chrootStore);
+            Store::Params params2;
+            params2["root"] = chrootStore;
+            return std::make_shared<LocalStore>(params2);
+        } else
             return std::make_shared<LocalStore>(params);
     } else if (uri == "daemon") {
         return std::make_shared<UDSRemoteStore>(params);

From 1cb376d60e3a7d0742d92fa2ea1ebebba0a513e5 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 23 Jun 2022 17:18:22 +0200
Subject: [PATCH 2/3] Fix typo

Co-authored-by: Cole Helbling <cole.e.helbling@outlook.com>
---
 src/libstore/store-api.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index b46b3066b..91080a2af 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -1326,9 +1326,9 @@ std::shared_ptr<Store> openFromNonUri(const std::string & uri, const Store::Para
                store in ~/.local/share/nix/root. */
             auto chrootStore = getDataDir() + "/nix/root";
             if (!pathExists(chrootStore))
-                warn("'/nix' does not exists, so Nix will use '%s' as a chroot store", chrootStore);
+                warn("'/nix' does not exist, so Nix will use '%s' as a chroot store", chrootStore);
             else
-                debug("'/nix' does not exists, so Nix will use '%s' as a chroot store", chrootStore);
+                debug("'/nix' does not exist, so Nix will use '%s' as a chroot store", chrootStore);
             Store::Params params2;
             params2["root"] = chrootStore;
             return std::make_shared<LocalStore>(params2);

From 30d4aa5dd651813578b67d70ffbcd0446f6f0fe7 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Fri, 24 Jun 2022 23:35:21 +0200
Subject: [PATCH 3/3] Only do the auto chroot store on Linux

---
 src/libstore/store-api.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 91080a2af..53b1a8777 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -1320,6 +1320,7 @@ std::shared_ptr<Store> openFromNonUri(const std::string & uri, const Store::Para
             return std::make_shared<LocalStore>(params);
         else if (pathExists(settings.nixDaemonSocketFile))
             return std::make_shared<UDSRemoteStore>(params);
+        #if __linux__
         else if (!pathExists(stateDir) && params.empty() && getuid() != 0) {
             /* If /nix doesn't exist, there is no daemon socket, and
                we're not root, then automatically set up a chroot
@@ -1332,7 +1333,9 @@ std::shared_ptr<Store> openFromNonUri(const std::string & uri, const Store::Para
             Store::Params params2;
             params2["root"] = chrootStore;
             return std::make_shared<LocalStore>(params2);
-        } else
+        }
+        #endif
+        else
             return std::make_shared<LocalStore>(params);
     } else if (uri == "daemon") {
         return std::make_shared<UDSRemoteStore>(params);