libstore/build: copy ca-certificates too

In b469c6509b, the ca-certificates file was missed. It should be copied too so that we don't end up bind-mounting a broken symlink. Change-Id: Ic9b292d602eb94b0e78f77f2a27a19d24665783c
libstore/build: use an allowlist approach to syscall filtering
2024-05-29 18:24:30 +02:00 · 2024-05-29 18:24:30 +02:00 · 2024-05-29 18:24:30 +02:00
165 changed files with 3315 additions and 3540 deletions
--- a/doc/manual/book.toml
+++ b/doc/manual/book.toml
@ -11,10 +11,6 @@ additional-js = ["redirects.js"]
 # to just submit a Gerrit CL by the web for trivial stuff.
 edit-url-template = "https://github.com/lix-project/lix/tree/main/doc/manual/{path}"
 git-repository-url = "https://git.lix.systems/lix-project/lix"
-# Folding by default would prevent things like "Ctrl+F for nix-env" from working
-# trivially, but the user should be able to fold if they want to.
-fold.enable = true
-fold.level = 30

 # Handles replacing @docroot@ with a path to ./src relative to that markdown file,
 # {{#include handlebars}}, and the @generated@ syntax used within these. it mostly
--- a/package.nix
+++ b/package.nix
@ -85,7 +85,6 @@
 let
  inherit (__forDefaults) canRunInstalled;
  inherit (lib) fileset;
-  inherit (stdenv) hostPlatform buildPlatform;

  version = lib.fileContents ./.version + versionSuffix;

@ -188,23 +187,23 @@ stdenv.mkDerivation (finalAttrs: {
  dontBuild = false;

  mesonFlags =
-    lib.optionals hostPlatform.isLinux [
+    lib.optionals stdenv.hostPlatform.isLinux [
      # You'd think meson could just find this in PATH, but busybox is in buildInputs,
      # which don't actually get added to PATH. And buildInputs is correct over
      # nativeBuildInputs since this should be a busybox executable on the host.
      "-Dsandbox-shell=${lib.getExe' busybox-sandbox-shell "busybox"}"
    ]
-    ++ lib.optional hostPlatform.isStatic "-Denable-embedded-sandbox-shell=true"
+    ++ lib.optional stdenv.hostPlatform.isStatic "-Denable-embedded-sandbox-shell=true"
    ++ lib.optional (finalAttrs.dontBuild) "-Denable-build=false"
    ++ [
      # mesonConfigurePhase automatically passes -Dauto_features=enabled,
      # so we must explicitly enable or disable features that we are not passing
      # dependencies for.
      (lib.mesonEnable "internal-api-docs" internalApiDocs)
-      (lib.mesonBool "enable-tests" finalAttrs.finalPackage.doCheck)
+      (lib.mesonBool "enable-tests" finalAttrs.doCheck)
      (lib.mesonBool "enable-docs" canRunInstalled)
    ]
-    ++ lib.optional (hostPlatform != buildPlatform) "--cross-file=${mesonCrossFile}";
+    ++ lib.optional (stdenv.hostPlatform != stdenv.buildPlatform) "--cross-file=${mesonCrossFile}";

  # We only include CMake so that Meson can locate toml11, which only ships CMake dependency metadata.
  dontUseCmakeConfigure = true;
@ -232,7 +231,7 @@ stdenv.mkDerivation (finalAttrs: {
      jq
      lsof
    ]
-    ++ lib.optional hostPlatform.isLinux util-linuxMinimal
+    ++ lib.optional stdenv.hostPlatform.isLinux util-linuxMinimal
    ++ lib.optional (!officialRelease && buildUnreleasedNotes) build-release-notes
    ++ lib.optional internalApiDocs doxygen;

@ -252,14 +251,14 @@ stdenv.mkDerivation (finalAttrs: {
      toml11
      lix-doc
    ]
-    ++ lib.optionals hostPlatform.isLinux [
+    ++ lib.optionals stdenv.hostPlatform.isLinux [
      libseccomp
      busybox-sandbox-shell
    ]
    ++ lib.optional internalApiDocs rapidcheck
-    ++ lib.optional hostPlatform.isx86_64 libcpuid
+    ++ lib.optional stdenv.hostPlatform.isx86_64 libcpuid
    # There have been issues building these dependencies
-    ++ lib.optional (hostPlatform == buildPlatform) aws-sdk-cpp-nix
+    ++ lib.optional (stdenv.hostPlatform == stdenv.buildPlatform) aws-sdk-cpp-nix
    ++ lib.optionals (finalAttrs.dontBuild) maybePropagatedInputs;

  checkInputs = [
@ -279,18 +278,18 @@ stdenv.mkDerivation (finalAttrs: {
  };

  preConfigure =
-    lib.optionalString (!finalAttrs.dontBuild && !hostPlatform.isStatic) ''
+    lib.optionalString (!finalAttrs.dontBuild && !stdenv.hostPlatform.isStatic) ''
      # Copy libboost_context so we don't get all of Boost in our closure.
      # https://github.com/NixOS/nixpkgs/issues/45462
      mkdir -p $out/lib
      cp -pd ${boost}/lib/{libboost_context*,libboost_thread*,libboost_system*} $out/lib
      rm -f $out/lib/*.a
    ''
-    + lib.optionalString (!finalAttrs.dontBuild && hostPlatform.isLinux && !hostPlatform.isStatic) ''
+    + lib.optionalString (!finalAttrs.dontBuild && stdenv.hostPlatform.isLinux) ''
      chmod u+w $out/lib/*.so.*
      patchelf --set-rpath $out/lib:${stdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
    ''
-    + lib.optionalString (!finalAttrs.dontBuild && hostPlatform.isDarwin) ''
+    + lib.optionalString (!finalAttrs.dontBuild && stdenv.hostPlatform.isDarwin) ''
      for LIB in $out/lib/*.dylib; do
        chmod u+w $LIB
        install_name_tool -id $LIB $LIB
@ -334,7 +333,7 @@ stdenv.mkDerivation (finalAttrs: {
      mkdir -p $doc/nix-support
      echo "doc manual $doc/share/doc/nix/manual" >> $doc/nix-support/hydra-build-products
    ''
-    + lib.optionalString hostPlatform.isStatic ''
+    + lib.optionalString stdenv.hostPlatform.isStatic ''
      mkdir -p $out/nix-support
      echo "file binary-dist $out/bin/nix" >> $out/nix-support/hydra-build-products
    ''
@ -365,12 +364,12 @@ stdenv.mkDerivation (finalAttrs: {
    runHook postInstallCheck
  '';

-  separateDebugInfo = !hostPlatform.isStatic && !finalAttrs.dontBuild;
+  separateDebugInfo = !stdenv.hostPlatform.isStatic && !finalAttrs.dontBuild;

  strictDeps = true;

  # strictoverflow is disabled because we trap on signed overflow instead
-  hardeningDisable = [ "strictoverflow" ] ++ lib.optional hostPlatform.isStatic "pie";
+  hardeningDisable = [ "strictoverflow" ] ++ lib.optional stdenv.hostPlatform.isStatic "pie";

  meta = {
    mainProgram = "nix";
@ -400,7 +399,7 @@ stdenv.mkDerivation (finalAttrs: {
        check-syscalls,
      }:
      let
-        glibcFix = lib.optionalAttrs (buildPlatform.isLinux && glibcLocales != null) {
+        glibcFix = lib.optionalAttrs (stdenv.buildPlatform.isLinux && glibcLocales != null) {
          # Required to make non-NixOS Linux not complain about missing locale files during configure in a dev shell
          LOCALE_ARCHIVE = "${lib.getLib pkgs.glibcLocales}/lib/locale/locale-archive";
        };
@ -418,19 +417,13 @@ stdenv.mkDerivation (finalAttrs: {

          name = "lix-shell-env";

-          # finalPackage is necessary to propagate stuff that is set by mkDerivation itself,
-          # like doCheck.
-          inputsFrom = [ finalAttrs.finalPackage ];
+          inputsFrom = [ finalAttrs ];

          # For Meson to find Boost.
          env = finalAttrs.env;

-          # I guess this is necessary because mesonFlags to mkDerivation doesn't propagate in inputsFrom,
-          # which only propagates stuff set in hooks? idk.
-          inherit (finalAttrs) mesonFlags;
-
          packages =
-            lib.optional (stdenv.cc.isClang && hostPlatform == buildPlatform) clang-tools_llvm
+            lib.optional (stdenv.cc.isClang && stdenv.hostPlatform == stdenv.buildPlatform) clang-tools_llvm
            ++ [
              check-syscalls
              just
@ -444,41 +437,37 @@ stdenv.mkDerivation (finalAttrs: {
              llvmPackages.clang-unwrapped.dev
            ]
            ++ lib.optional (pre-commit-checks ? enabledPackages) pre-commit-checks.enabledPackages
-            ++ lib.optional (lib.meta.availableOn buildPlatform clangbuildanalyzer) clangbuildanalyzer
+            ++ lib.optional (lib.meta.availableOn stdenv.buildPlatform clangbuildanalyzer) clangbuildanalyzer
            ++ finalAttrs.checkInputs;

          shellHook = ''
            # don't re-run the hook in (other) nested nix-shells
-            function lixShellHook() {
-              if [[ $name != lix-shell-env ]]; then
-                return;
-              fi
+            if [[ $name != lix-shell-env ]]; then
+              return;
+            fi

-              PATH=$prefix/bin:$PATH
-              unset PYTHONPATH
-              export MANPATH=$out/share/man:$MANPATH
+            PATH=$prefix/bin:$PATH
+            unset PYTHONPATH
+            export MANPATH=$out/share/man:$MANPATH

-              # Make bash completion work.
-              XDG_DATA_DIRS+=:$out/share
+            # Make bash completion work.
+            XDG_DATA_DIRS+=:$out/share

-              ${lib.optionalString (pre-commit-checks ? shellHook) pre-commit-checks.shellHook}
-              # Allow `touch .nocontribmsg` to turn this notice off.
-              if ! [[ -f .nocontribmsg ]]; then
-                cat ${contribNotice}
-              fi
+            ${lib.optionalString (pre-commit-checks ? shellHook) pre-commit-checks.shellHook}
+            # Allow `touch .nocontribmsg` to turn this notice off.
+            if ! [[ -f .nocontribmsg ]]; then
+              cat ${contribNotice}
+            fi

-              # Install the Gerrit commit-msg hook.
-              # (git common dir is the main .git, including for worktrees)
-              if gitcommondir=$(git rev-parse --git-common-dir 2>/dev/null) && [[ ! -f "$gitcommondir/hooks/commit-msg" ]]; then
-                echo 'Installing Gerrit commit-msg hook (adds Change-Id to commit messages)' >&2
-                mkdir -p "$gitcommondir/hooks"
-                curl -s -Lo "$gitcommondir/hooks/commit-msg" https://gerrit.lix.systems/tools/hooks/commit-msg
-                chmod u+x "$gitcommondir/hooks/commit-msg"
-              fi
-              unset gitcommondir
-            }
-
-            lixShellHook
+            # Install the Gerrit commit-msg hook.
+            # (git common dir is the main .git, including for worktrees)
+            if gitcommondir=$(git rev-parse --git-common-dir 2>/dev/null) && [[ ! -f "$gitcommondir/hooks/commit-msg" ]]; then
+              echo 'Installing Gerrit commit-msg hook (adds Change-Id to commit messages)' >&2
+              mkdir -p "$gitcommondir/hooks"
+              curl -s -Lo "$gitcommondir/hooks/commit-msg" https://gerrit.lix.systems/tools/hooks/commit-msg
+              chmod u+x "$gitcommondir/hooks/commit-msg"
+            fi
+            unset gitcommondir
          '';
        }
      );
--- a/perl/lib/Nix/Store.xs
+++ b/perl/lib/Nix/Store.xs
@ -11,6 +11,7 @@
 #include "derivations.hh"
 #include "globals.hh"
 #include "store-api.hh"
+#include "util.hh"
 #include "crypto.hh"

 #include <sodium.h>
--- a/src/libcmd/common-eval-args.cc
+++ b/src/libcmd/common-eval-args.cc
@ -2,6 +2,7 @@
 #include "common-eval-args.hh"
 #include "shared.hh"
 #include "filetransfer.hh"
+#include "util.hh"
 #include "eval.hh"
 #include "fetchers.hh"
 #include "registry.hh"
--- a/src/libcmd/editor-for.cc
+++ b/src/libcmd/editor-for.cc
@ -1,5 +1,5 @@
+#include "util.hh"
 #include "editor-for.hh"
-#include "environment-variables.hh"
 #include "source-path.hh"

 namespace nix {
--- a/src/libcmd/installable-attr-path.cc
+++ b/src/libcmd/installable-attr-path.cc
@ -1,6 +1,7 @@
 #include "globals.hh"
 #include "installable-attr-path.hh"
 #include "outputs-spec.hh"
+#include "util.hh"
 #include "command.hh"
 #include "attr-path.hh"
 #include "common-eval-args.hh"
--- a/src/libcmd/installable-attr-path.hh
+++ b/src/libcmd/installable-attr-path.hh
@ -4,6 +4,7 @@
 #include "globals.hh"
 #include "installable-value.hh"
 #include "outputs-spec.hh"
+#include "util.hh"
 #include "command.hh"
 #include "attr-path.hh"
 #include "common-eval-args.hh"
--- a/src/libcmd/installable-flake.cc
+++ b/src/libcmd/installable-flake.cc
@ -2,6 +2,7 @@
 #include "installable-flake.hh"
 #include "installable-derived-path.hh"
 #include "outputs-spec.hh"
+#include "util.hh"
 #include "command.hh"
 #include "attr-path.hh"
 #include "common-eval-args.hh"
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@ -3,21 +3,26 @@
 #include "installable-derived-path.hh"
 #include "installable-attr-path.hh"
 #include "installable-flake.hh"
-#include "logging.hh"
 #include "outputs-spec.hh"
+#include "util.hh"
 #include "command.hh"
 #include "attr-path.hh"
 #include "common-eval-args.hh"
 #include "derivations.hh"
+#include "eval-inline.hh"
 #include "eval.hh"
 #include "eval-settings.hh"
+#include "get-drvs.hh"
 #include "store-api.hh"
 #include "shared.hh"
 #include "flake/flake.hh"
 #include "eval-cache.hh"
+#include "url.hh"
 #include "registry.hh"
 #include "build-result.hh"

+#include <regex>
+#include <queue>

 #include <nlohmann/json.hpp>

--- a/src/libcmd/installables.hh
+++ b/src/libcmd/installables.hh
@ -1,6 +1,7 @@
 #pragma once
 ///@file

+#include "util.hh"
 #include "path.hh"
 #include "outputs-spec.hh"
 #include "derived-path.hh"
--- a/src/libcmd/markdown.cc
+++ b/src/libcmd/markdown.cc
@ -1,7 +1,6 @@
 #include "markdown.hh"
-#include "error.hh"
+#include "util.hh"
 #include "finally.hh"
-#include "terminal.hh"

 #include <sys/queue.h>
 #include <lowdown.h>
--- a/src/libcmd/repl-interacter.cc
+++ b/src/libcmd/repl-interacter.cc
@ -1,7 +1,3 @@
-#include "error.hh"
-#include "file-system.hh"
-#include "logging.hh"
-#include <csignal>
 #include <cstdio>
 #include <iostream>
 #include <string>
@ -22,8 +18,11 @@ extern "C" {
 }
 #endif

+#include "signals.hh"
 #include "finally.hh"
 #include "repl-interacter.hh"
+#include "util.hh"
+#include "repl.hh"

 namespace nix {

--- a/src/libcmd/repl.cc
+++ b/src/libcmd/repl.cc
@ -31,7 +31,6 @@
 #include "print.hh"
 #include "progress-bar.hh"
 #include "gc-small-vector.hh"
-#include "users.hh"

 #if HAVE_BOEHMGC
 #define GC_INCLUDE_NEW
--- a/src/libexpr/attr-path.cc
+++ b/src/libexpr/attr-path.cc
@ -1,5 +1,6 @@
 #include "attr-path.hh"
 #include "eval-inline.hh"
+#include "util.hh"


 namespace nix {
--- a/src/libexpr/eval-cache.cc
+++ b/src/libexpr/eval-cache.cc
@ -1,8 +1,8 @@
 #include "eval-cache.hh"
 #include "sqlite.hh"
 #include "eval.hh"
+#include "eval-inline.hh"
 #include "store-api.hh"
-#include "users.hh"

 namespace nix::eval_cache {

--- a/src/libexpr/eval-settings.cc
+++ b/src/libexpr/eval-settings.cc
@ -1,7 +1,6 @@
-#include "file-system.hh"
 #include "globals.hh"
 #include "profiles.hh"
-#include "users.hh"
+#include "eval.hh"
 #include "eval-settings.hh"

 namespace nix {
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@ -5,6 +5,7 @@
 #include "print-options.hh"
 #include "shared.hh"
 #include "types.hh"
+#include "util.hh"
 #include "store-api.hh"
 #include "derivations.hh"
 #include "downstream-placeholder.hh"
--- a/src/libexpr/flake/config.cc
+++ b/src/libexpr/flake/config.cc
@ -1,6 +1,5 @@
 #include "flake.hh"
-#include "logging.hh"
-#include "users.hh"
+#include "globals.hh"
 #include "fetch-settings.hh"

 #include <nlohmann/json.hpp>
--- a/src/libexpr/flake/flake.cc
+++ b/src/libexpr/flake/flake.cc
@ -8,7 +8,6 @@
 #include "fetchers.hh"
 #include "finally.hh"
 #include "fetch-settings.hh"
-#include "terminal.hh"

 namespace nix {

--- a/src/libexpr/get-drvs.cc
+++ b/src/libexpr/get-drvs.cc
@ -1,4 +1,5 @@
 #include "get-drvs.hh"
+#include "util.hh"
 #include "eval-inline.hh"
 #include "derivations.hh"
 #include "store-api.hh"
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@ -2,6 +2,7 @@
 #include "derivations.hh"
 #include "eval.hh"
 #include "symbol-table.hh"
+#include "util.hh"
 #include "print.hh"
 #include "escape-string.hh"

--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@ -19,7 +19,7 @@
 #include <variant>

 #include "finally.hh"
-#include "users.hh"
+#include "util.hh"

 #include "nixexpr.hh"
 #include "eval.hh"
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@ -9,8 +9,8 @@
 #include "json-to-value.hh"
 #include "names.hh"
 #include "path-references.hh"
-#include "processes.hh"
 #include "store-api.hh"
+#include "util.hh"
 #include "value-to-json.hh"
 #include "value-to-xml.hh"
 #include "primops.hh"
--- a/src/libexpr/print-ambiguous.cc
+++ b/src/libexpr/print-ambiguous.cc
@ -1,7 +1,6 @@
 #include "print-ambiguous.hh"
-#include "attr-set.hh"
-#include "logging.hh"
 #include "print.hh"
+#include "eval.hh"
 #include "signals.hh"
 #include "escape-string.hh"

--- a/src/libexpr/print.cc
+++ b/src/libexpr/print.cc
@ -9,7 +9,6 @@
 #include "english.hh"
 #include "signals.hh"
 #include "eval.hh"
-#include "terminal.hh"

 namespace nix {

--- a/src/libexpr/search-path.cc
+++ b/src/libexpr/search-path.cc
@ -1,4 +1,5 @@
 #include "search-path.hh"
+#include "util.hh"

 namespace nix {

--- a/src/libexpr/value-to-json.cc
+++ b/src/libexpr/value-to-json.cc
@ -1,5 +1,6 @@
 #include "value-to-json.hh"
 #include "eval-inline.hh"
+#include "util.hh"
 #include "signals.hh"
 #include "store-api.hh"

--- a/src/libexpr/value-to-xml.cc
+++ b/src/libexpr/value-to-xml.cc
@ -1,7 +1,11 @@
 #include "value-to-xml.hh"
 #include "xml-writer.hh"
+#include "eval-inline.hh"
+#include "util.hh"
 #include "signals.hh"

+#include <cstdlib>
+

 namespace nix {

--- a/src/libexpr/value/context.hh
+++ b/src/libexpr/value/context.hh
@ -1,6 +1,7 @@
 #pragma once
 ///@file

+#include "util.hh"
 #include "comparator.hh"
 #include "derived-path.hh"
 #include "variant-wrapper.hh"
--- a/src/libfetchers/cache.cc
+++ b/src/libfetchers/cache.cc
@ -2,7 +2,6 @@
 #include "sqlite.hh"
 #include "sync.hh"
 #include "store-api.hh"
-#include "users.hh"

 #include <nlohmann/json.hpp>

--- a/src/libfetchers/fetch-settings.hh
+++ b/src/libfetchers/fetch-settings.hh
@ -3,6 +3,7 @@

 #include "types.hh"
 #include "config.hh"
+#include "util.hh"

 #include <map>
 #include <limits>
--- a/src/libfetchers/fetch-to-store.hh
+++ b/src/libfetchers/fetch-to-store.hh
@ -3,6 +3,7 @@

 #include "source-path.hh"
 #include "store-api.hh"
+#include "util.hh"
 #include "repair-flag.hh"
 #include "content-address.hh"

--- a/src/libfetchers/git.cc
+++ b/src/libfetchers/git.cc
@ -1,12 +1,11 @@
 #include "fetchers.hh"
 #include "cache.hh"
 #include "globals.hh"
-#include "processes.hh"
 #include "tarfile.hh"
 #include "store-api.hh"
 #include "url-parts.hh"
 #include "pathlocks.hh"
-#include "users.hh"
+#include "util.hh"
 #include "git.hh"
 #include "logging.hh"
 #include "finally.hh"
--- a/src/libfetchers/mercurial.cc
+++ b/src/libfetchers/mercurial.cc
@ -1,9 +1,9 @@
 #include "fetchers.hh"
 #include "cache.hh"
-#include "processes.hh"
+#include "globals.hh"
+#include "tarfile.hh"
 #include "store-api.hh"
 #include "url-parts.hh"
-#include "users.hh"

 #include "fetch-settings.hh"

--- a/src/libfetchers/registry.cc
+++ b/src/libfetchers/registry.cc
@ -1,6 +1,6 @@
 #include "registry.hh"
 #include "fetchers.hh"
-#include "users.hh"
+#include "util.hh"
 #include "globals.hh"
 #include "store-api.hh"
 #include "local-fs-store.hh"
--- a/src/libmain/common-args.cc
+++ b/src/libmain/common-args.cc
@ -2,7 +2,6 @@
 #include "args/root.hh"
 #include "globals.hh"
 #include "loggers.hh"
-#include "logging.hh"

 namespace nix {

--- a/src/libmain/loggers.cc
+++ b/src/libmain/loggers.cc
@ -1,6 +1,6 @@
-#include "environment-variables.hh"
 #include "loggers.hh"
 #include "progress-bar.hh"
+#include "util.hh"

 namespace nix {

--- a/src/libmain/progress-bar.cc
+++ b/src/libmain/progress-bar.cc
@ -1,8 +1,8 @@
 #include "progress-bar.hh"
+#include "util.hh"
 #include "sync.hh"
 #include "store-api.hh"
 #include "names.hh"
-#include "terminal.hh"

 #include <atomic>
 #include <map>
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@ -2,10 +2,10 @@
 #include "shared.hh"
 #include "store-api.hh"
 #include "gc-store.hh"
+#include "util.hh"
 #include "signals.hh"
 #include "loggers.hh"
 #include "progress-bar.hh"
-#include "current-process.hh"

 #include <algorithm>
 #include <cctype>
--- a/src/libmain/shared.hh
+++ b/src/libmain/shared.hh
@ -1,12 +1,12 @@
 #pragma once
 ///@file

+#include "util.hh"
 #include "args.hh"
 #include "args/root.hh"
 #include "common-args.hh"
 #include "path.hh"
 #include "derived-path.hh"
-#include "processes.hh"
 #include "exit.hh"

 #include <signal.h>
--- a/src/libstore/build/child.cc
+++ b/src/libstore/build/child.cc
@ -1,33 +0,0 @@
-#include "current-process.hh"
-#include "logging.hh"
-
-namespace nix {
-
-void commonChildInit()
-{
-    logger = makeSimpleLogger();
-
-    const static std::string pathNullDevice = "/dev/null";
-    restoreProcessContext(false);
-
-    /* Put the child in a separate session (and thus a separate
-       process group) so that it has no controlling terminal (meaning
-       that e.g. ssh cannot open /dev/tty) and it doesn't receive
-       terminal signals. */
-    if (setsid() == -1)
-        throw SysError("creating a new session");
-
-    /* Dup stderr to stdout. */
-    if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1)
-        throw SysError("cannot dup stderr into stdout");
-
-    /* Reroute stdin to /dev/null. */
-    int fdDevNull = open(pathNullDevice.c_str(), O_RDWR);
-    if (fdDevNull == -1)
-        throw SysError("cannot open '%1%'", pathNullDevice);
-    if (dup2(fdDevNull, STDIN_FILENO) == -1)
-        throw SysError("cannot dup null device into stdin");
-    close(fdDevNull);
-}
-
-}
--- a/src/libstore/build/child.hh
+++ b/src/libstore/build/child.hh
@ -1,11 +0,0 @@
-#pragma once
-///@file
-
-namespace nix {
-
-/**
- * Common initialisation performed in child processes.
- */
-void commonChildInit();
-
-}
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@ -5,6 +5,7 @@
 #include "builtins/buildenv.hh"
 #include "references.hh"
 #include "finally.hh"
+#include "util.hh"
 #include "archive.hh"
 #include "compression.hh"
 #include "common-protocol.hh"
--- a/src/libstore/build/hook-instance.cc
+++ b/src/libstore/build/hook-instance.cc
@ -1,5 +1,3 @@
-#include "child.hh"
-#include "file-system.hh"
 #include "globals.hh"
 #include "hook-instance.hh"

--- a/src/libstore/build/hook-instance.hh
+++ b/src/libstore/build/hook-instance.hh
@ -2,7 +2,6 @@
 ///@file

 #include "logging.hh"
-#include "processes.hh"
 #include "serialise.hh"

 namespace nix {
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@ -6,6 +6,7 @@
 #include "builtins/buildenv.hh"
 #include "path-references.hh"
 #include "finally.hh"
+#include "util.hh"
 #include "archive.hh"
 #include "compression.hh"
 #include "daemon.hh"
@ -14,8 +15,6 @@
 #include "cgroup.hh"
 #include "personality.hh"
 #include "namespaces.hh"
-#include "child.hh"
-#include "unix-domain-socket.hh"

 #include <regex>
 #include <queue>
@ -63,11 +62,6 @@ extern "C" int sandbox_init_with_parameters(const char *profile, uint64_t flags,

 namespace nix {

-/**
- * The system for which Nix is compiled.
- */
-constexpr std::string_view nativeSystem = SYSTEM;
-
 void handleDiffHook(
    uid_t uid, uid_t gid,
    const Path & tryA, const Path & tryB,
--- a/src/libstore/build/local-derivation-goal.hh
+++ b/src/libstore/build/local-derivation-goal.hh
@ -3,7 +3,6 @@

 #include "derivation-goal.hh"
 #include "local-store.hh"
-#include "processes.hh"

 namespace nix {

--- a/src/libstore/common-protocol.cc
+++ b/src/libstore/common-protocol.cc
@ -1,8 +1,11 @@
 #include "serialise.hh"
+#include "util.hh"
 #include "path-with-outputs.hh"
 #include "store-api.hh"
+#include "build-result.hh"
 #include "common-protocol.hh"
 #include "common-protocol-impl.hh"
+#include "archive.hh"
 #include "derivations.hh"

 #include <nlohmann/json.hpp>
--- a/src/libstore/crypto.cc
+++ b/src/libstore/crypto.cc
@ -1,7 +1,6 @@
 #include "crypto.hh"
-#include "file-system.hh"
+#include "util.hh"
 #include "globals.hh"
-#include "strings.hh"

 #include <sodium.h>

--- a/src/libstore/crypto.hh
+++ b/src/libstore/crypto.hh
@ -1,9 +1,9 @@
 #pragma once
 ///@file

+#include "types.hh"

 #include <map>
-#include <string>

 namespace nix {

--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@ -3,6 +3,7 @@
 #include "store-api.hh"
 #include "globals.hh"
 #include "types.hh"
+#include "util.hh"
 #include "split.hh"
 #include "common-protocol.hh"
 #include "common-protocol-impl.hh"
--- a/src/libstore/derived-path.hh
+++ b/src/libstore/derived-path.hh
@ -1,7 +1,7 @@
 #pragma once
 ///@file

-#include "config.hh"
+#include "util.hh"
 #include "path.hh"
 #include "outputs-spec.hh"
 #include "comparator.hh"
--- a/src/libstore/filetransfer.cc
+++ b/src/libstore/filetransfer.cc
@ -1,5 +1,5 @@
 #include "filetransfer.hh"
-#include "namespaces.hh"
+#include "util.hh"
 #include "globals.hh"
 #include "store-api.hh"
 #include "s3.hh"
@ -19,6 +19,7 @@
 #include <algorithm>
 #include <cmath>
 #include <cstring>
+#include <iostream>
 #include <queue>
 #include <random>
 #include <thread>
@ -50,6 +51,7 @@ struct curlFileTransfer : public FileTransfer
        std::function<void(TransferItem &, std::string_view data)> dataCallback;
        CURL * req = 0;
        bool active = false; // whether the handle has been added to the multi object
+        bool headersProcessed = false;
        std::string statusMsg;

        unsigned int attempt = 0;
@ -134,11 +136,35 @@ struct curlFileTransfer : public FileTransfer

        std::exception_ptr writeException;

+        std::optional<std::string> getHeader(const char * name)
+        {
+            curl_header * result;
+            auto e = curl_easy_header(req, name, 0, CURLH_HEADER, -1, &result);
+            if (e == CURLHE_OK) {
+                return result->value;
+            } else if (e == CURLHE_MISSING || e == CURLHE_NOHEADERS) {
+                return std::nullopt;
+            } else {
+                throw nix::Error("unexpected error from curl_easy_header(): %i", e);
+            }
+        }
+
        size_t writeCallback(void * contents, size_t size, size_t nmemb)
        {
            const size_t realSize = size * nmemb;

            try {
+                if (!headersProcessed) {
+                    if (auto h = getHeader("content-encoding")) {
+                        encoding = std::move(*h);
+                    }
+                    if (auto h = getHeader("accept-ranges"); h && *h == "bytes") {
+                        acceptRanges = true;
+                    }
+
+                    headersProcessed = true;
+                }
+
                result.bodySize += realSize;

                if (successfulStatuses.count(getHTTPStatus()) && this->dataCallback) {
@ -174,31 +200,7 @@ struct curlFileTransfer : public FileTransfer
                statusMsg = trim(match.str(1));
                acceptRanges = false;
                encoding = "";
-            } else {
-                auto i = line.find(':');
-                if (i != std::string::npos) {
-                    std::string name = toLower(trim(line.substr(0, i)));
-
-                    if (name == "etag") {
-                        result.etag = trim(line.substr(i + 1));
-                    }
-
-                    else if (name == "content-encoding")
-                        encoding = trim(line.substr(i + 1));
-
-                    else if (name == "accept-ranges" && toLower(trim(line.substr(i + 1))) == "bytes")
-                        acceptRanges = true;
-
-                    else if (name == "link" || name == "x-amz-meta-link") {
-                        auto value = trim(line.substr(i + 1));
-                        static std::regex linkRegex("<([^>]*)>; rel=\"immutable\"", std::regex::extended | std::regex::icase);
-                        if (std::smatch match; std::regex_match(value, match, linkRegex))
-                            result.immutableUrl = match.str(1);
-                        else
-                            debug("got invalid link header '%s'", value);
-                        warn("foo %s", value);
-                    }
-                }
+                headersProcessed = false;
            }
            return realSize;
        }
@ -334,6 +336,25 @@ struct curlFileTransfer : public FileTransfer
            debug("finished %s of '%s'; curl status = %d, HTTP status = %d, body = %d bytes",
                request.verb(), request.uri, code, httpStatus, result.bodySize);

+            auto link = getHeader("link");
+            if (!link) {
+                link = getHeader("x-amz-meta-link");
+            }
+            if (link) {
+                static std::regex linkRegex(
+                    "<([^>]*)>; rel=\"immutable\"", std::regex::extended | std::regex::icase
+                );
+                if (std::smatch match; std::regex_match(*link, match, linkRegex)) {
+                    result.immutableUrl = match.str(1);
+                } else {
+                    debug("got invalid link header '%s'", *link);
+                }
+            }
+
+            if (auto etag = getHeader("etag")) {
+                result.etag = std::move(*etag);
+            }
+
            // this has to happen here until we can return an actual future.
            // wrapping user `callback`s instead is not possible because the
            // Callback api expects std::functions, and copying Callbacks is
--- a/src/libstore/filetransfer.hh
+++ b/src/libstore/filetransfer.hh
@ -1,9 +1,8 @@
 #pragma once
 ///@file

-#include "logging.hh"
-#include "serialise.hh"
 #include "types.hh"
+#include "hash.hh"
 #include "config.hh"

 #include <string>
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@ -1,14 +1,16 @@
+#include "derivations.hh"
 #include "globals.hh"
 #include "local-store.hh"
-#include "pathlocks.hh"
-#include "processes.hh"
 #include "signals.hh"
 #include "finally.hh"
-#include "unix-domain-socket.hh"

+#include <functional>
 #include <queue>
+#include <algorithm>
 #include <regex>
+#include <random>

+#include <climits>
 #include <errno.h>
 #include <fcntl.h>
 #include <poll.h>
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@ -1,15 +1,12 @@
-#include "environment-variables.hh"
 #include "globals.hh"
-#include "file-system.hh"
-#include "logging.hh"
-#include "strings.hh"
-#include "users.hh"
+#include "util.hh"
+#include "archive.hh"
 #include "args.hh"
 #include "abstract-setting-to-json.hh"
 #include "compute-levels.hh"
-#include "current-process.hh"

 #include <algorithm>
+#include <map>
 #include <mutex>
 #include <thread>
 #include <dlfcn.h>
@ -28,7 +25,6 @@
 #include "config-impl.hh"

 #ifdef __APPLE__
-#include "processes.hh"
 #include <curl/curl.h>
 #include <sys/sysctl.h>
 #endif
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@ -1,9 +1,9 @@
 #pragma once
 ///@file

-#include "environment-variables.hh"
 #include "types.hh"
 #include "config.hh"
+#include "util.hh"

 #include <map>
 #include <limits>
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@ -3,9 +3,11 @@

 #include "sqlite.hh"

+#include "pathlocks.hh"
 #include "store-api.hh"
 #include "indirect-root-store.hh"
 #include "sync.hh"
+#include "util.hh"

 #include <chrono>
 #include <future>
--- a/src/libstore/lock.cc
+++ b/src/libstore/lock.cc
@ -1,6 +1,4 @@
 #include "lock.hh"
-#include "logging.hh"
-#include "file-system.hh"
 #include "globals.hh"
 #include "pathlocks.hh"

--- a/src/libstore/machines.cc
+++ b/src/libstore/machines.cc
@ -1,7 +1,7 @@
 #include "machines.hh"
+#include "util.hh"
 #include "globals.hh"
 #include "store-api.hh"
-#include "strings.hh"

 #include <algorithm>

--- a/src/libstore/meson.build
+++ b/src/libstore/meson.build
@ -79,7 +79,6 @@ libstore_sources = files(
  'store-api.cc',
  'uds-remote-store.cc',
  'worker-protocol.cc',
-  'build/child.cc',
  'build/derivation-goal.cc',
  'build/drv-output-substitution-goal.cc',
  'build/entry-points.cc',
@ -97,7 +96,6 @@ libstore_sources = files(

 libstore_headers = files(
  'binary-cache-store.hh',
-  'build/child.hh',
  'build/derivation-goal.hh',
  'build/drv-output-substitution-goal.hh',
  'build/goal.hh',
--- a/src/libstore/names.cc
+++ b/src/libstore/names.cc
@ -1,5 +1,5 @@
 #include "names.hh"
-#include "strings.hh"
+#include "util.hh"

 #include <regex>

--- a/src/libstore/nar-info-disk-cache.cc
+++ b/src/libstore/nar-info-disk-cache.cc
@ -1,9 +1,7 @@
 #include "nar-info-disk-cache.hh"
-#include "logging.hh"
 #include "sync.hh"
 #include "sqlite.hh"
 #include "globals.hh"
-#include "users.hh"

 #include <sqlite3.h>
 #include <nlohmann/json.hpp>
--- a/src/libstore/optimise-store.cc
+++ b/src/libstore/optimise-store.cc
@ -1,3 +1,4 @@
+#include "util.hh"
 #include "local-store.hh"
 #include "globals.hh"
 #include "signals.hh"
--- a/src/libstore/outputs-spec.cc
+++ b/src/libstore/outputs-spec.cc
@ -1,10 +1,10 @@
 #include <regex>
 #include <nlohmann/json.hpp>

+#include "util.hh"
 #include "regex-combinators.hh"
 #include "outputs-spec.hh"
 #include "path-regex.hh"
-#include "strings.hh"

 namespace nix {

--- a/src/libstore/path-references.cc
+++ b/src/libstore/path-references.cc
@ -1,8 +1,12 @@
 #include "path-references.hh"
 #include "hash.hh"
+#include "util.hh"
 #include "archive.hh"

 #include <map>
+#include <cstdlib>
+#include <mutex>
+#include <algorithm>


 namespace nix {
--- a/src/libstore/pathlocks.cc
+++ b/src/libstore/pathlocks.cc
@ -1,8 +1,10 @@
 #include "pathlocks.hh"
-#include "logging.hh"
+#include "util.hh"
 #include "signals.hh"
+#include "sync.hh"

 #include <cerrno>
+#include <cstdlib>

 #include <fcntl.h>
 #include <sys/types.h>
--- a/src/libstore/pathlocks.hh
+++ b/src/libstore/pathlocks.hh
@ -1,7 +1,7 @@
 #pragma once
 ///@file

-#include "file-descriptor.hh"
+#include "util.hh"

 namespace nix {

--- a/src/libstore/profiles.cc
+++ b/src/libstore/profiles.cc
@ -1,7 +1,7 @@
 #include "profiles.hh"
 #include "store-api.hh"
 #include "local-fs-store.hh"
-#include "users.hh"
+#include "util.hh"

 #include <sys/types.h>
 #include <sys/stat.h>
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@ -1,4 +1,5 @@
 #include "serialise.hh"
+#include "util.hh"
 #include "signals.hh"
 #include "path-with-outputs.hh"
 #include "gc-store.hh"
--- a/src/libstore/serve-protocol.cc
+++ b/src/libstore/serve-protocol.cc
@ -1,9 +1,11 @@
 #include "serialise.hh"
+#include "util.hh"
 #include "path-with-outputs.hh"
 #include "store-api.hh"
 #include "build-result.hh"
 #include "serve-protocol.hh"
 #include "serve-protocol-impl.hh"
+#include "archive.hh"
 #include "path-info.hh"

 #include <nlohmann/json.hpp>
--- a/src/libstore/sqlite.cc
+++ b/src/libstore/sqlite.cc
@ -1,11 +1,12 @@
 #include "sqlite.hh"
 #include "globals.hh"
-#include "logging.hh"
+#include "util.hh"
 #include "signals.hh"
 #include "url.hh"

 #include <sqlite3.h>

+#include <atomic>

 namespace nix {

--- a/src/libstore/ssh.cc
+++ b/src/libstore/ssh.cc
@ -1,9 +1,5 @@
-#include "current-process.hh"
-#include "environment-variables.hh"
 #include "ssh.hh"
 #include "finally.hh"
-#include "logging.hh"
-#include "strings.hh"

 namespace nix {

--- a/src/libstore/ssh.hh
+++ b/src/libstore/ssh.hh
@ -1,8 +1,7 @@
 #pragma once
 ///@file

-#include "file-system.hh"
-#include "processes.hh"
+#include "util.hh"
 #include "sync.hh"

 namespace nix {
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@ -1,7 +1,9 @@
+#include "crypto.hh"
 #include "fs-accessor.hh"
 #include "globals.hh"
 #include "derivations.hh"
 #include "store-api.hh"
+#include "util.hh"
 #include "nar-info-disk-cache.hh"
 #include "thread-pool.hh"
 #include "url.hh"
@ -12,7 +14,6 @@
 // FIXME this should not be here, see TODO below on
 // `addMultipleToStore`.
 #include "worker-protocol.hh"
-#include "users.hh"

 #include <nlohmann/json.hpp>
 #include <regex>
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@ -1,7 +1,6 @@
 #pragma once
 ///@file

-#include "logging.hh"
 #include "nar-info.hh"
 #include "realisation.hh"
 #include "path.hh"
--- a/src/libstore/uds-remote-store.cc
+++ b/src/libstore/uds-remote-store.cc
@ -1,5 +1,4 @@
 #include "uds-remote-store.hh"
-#include "unix-domain-socket.hh"
 #include "worker-protocol.hh"

 #include <sys/types.h>
--- a/src/libstore/worker-protocol.cc
+++ b/src/libstore/worker-protocol.cc
@ -1,4 +1,5 @@
 #include "serialise.hh"
+#include "util.hh"
 #include "path-with-outputs.hh"
 #include "store-api.hh"
 #include "build-result.hh"
--- a/src/libutil/archive.cc
+++ b/src/libutil/archive.cc
@ -12,9 +12,8 @@
 #include <fcntl.h>

 #include "archive.hh"
-#include "file-system.hh"
+#include "util.hh"
 #include "config.hh"
-#include "logging.hh"
 #include "signals.hh"

 namespace nix {
--- a/src/libutil/archive.hh
+++ b/src/libutil/archive.hh
@ -3,7 +3,6 @@

 #include "types.hh"
 #include "serialise.hh"
-#include "file-system.hh"


 namespace nix {
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@ -2,10 +2,7 @@
 #include "args/root.hh"
 #include "hash.hh"
 #include "json-utils.hh"
-#include "environment-variables.hh"
-
 #include "experimental-features-json.hh"
-#include "logging.hh"

 #include <glob.h>

--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@ -1,17 +1,13 @@
 #pragma once
 ///@file

-#include "experimental-features.hh"
-#include "types.hh"
-#include <functional>
+#include <iostream>
 #include <map>
 #include <memory>
-#include <limits>

 #include <nlohmann/json_fwd.hpp>
-#include <optional>
-#include <set>

+#include "util.hh"

 namespace nix {

--- a/src/libutil/canon-path.cc
+++ b/src/libutil/canon-path.cc
@ -1,5 +1,5 @@
 #include "canon-path.hh"
-#include "file-system.hh"
+#include "util.hh"

 namespace nix {

--- a/src/libutil/cgroup.cc
+++ b/src/libutil/cgroup.cc
@ -1,17 +1,14 @@
-#include "logging.hh"
 #if __linux__

 #include "cgroup.hh"
-#include "file-system.hh"
+#include "util.hh"
 #include "finally.hh"
-#include "strings.hh"

 #include <chrono>
 #include <cmath>
 #include <regex>
 #include <unordered_set>
 #include <thread>
-#include <signal.h>

 #include <dirent.h>
 #include <mntent.h>
--- a/src/libutil/comparator.hh
+++ b/src/libutil/comparator.hh
@ -1,8 +1,6 @@
 #pragma once
 ///@file

-#include <tuple>
-
 #define DECLARE_ONE_CMP(PRE, QUAL, COMPARATOR, MY_TYPE) \
    PRE bool QUAL operator COMPARATOR(const MY_TYPE & other) const;
 #define DECLARE_EQUAL(prefix, qualification, my_type) \
--- a/src/libutil/compression.cc
+++ b/src/libutil/compression.cc
@ -1,5 +1,7 @@
 #include "compression.hh"
 #include "tarfile.hh"
+#include "util.hh"
+#include "finally.hh"
 #include "signals.hh"
 #include "logging.hh"

@ -11,6 +13,7 @@
 #include <brotli/decode.h>
 #include <brotli/encode.h>

+#include <iostream>

 namespace nix {

--- a/src/libutil/config-impl.hh
+++ b/src/libutil/config-impl.hh
@ -12,9 +12,7 @@
 * instantiation.
 */

-#include "args.hh"
 #include "config.hh"
-#include "logging.hh"

 namespace nix {

--- a/src/libutil/config.cc
+++ b/src/libutil/config.cc
@ -2,9 +2,6 @@
 #include "args.hh"
 #include "abstract-setting-to-json.hh"
 #include "experimental-features.hh"
-#include "file-system.hh"
-#include "logging.hh"
-#include "strings.hh"

 #include "config-impl.hh"

--- a/src/libutil/current-process.cc
+++ b/src/libutil/current-process.cc
@ -1,111 +0,0 @@
-#include "current-process.hh"
-#include "error.hh"
-#include "file-system.hh"
-#include "logging.hh"
-#include "namespaces.hh"
-#include "signals.hh"
-#include "strings.hh"
-
-#ifdef __APPLE__
-# include <mach-o/dyld.h>
-#endif
-
-#if __linux__
-# include <sys/resource.h>
-#endif
-
-#include <sys/mount.h>
-#include <cgroup.hh>
-
-namespace nix {
-
-unsigned int getMaxCPU()
-{
-    #if __linux__
-    try {
-        auto cgroupFS = getCgroupFS();
-        if (!cgroupFS) return 0;
-
-        auto cgroups = getCgroups("/proc/self/cgroup");
-        auto cgroup = cgroups[""];
-        if (cgroup == "") return 0;
-
-        auto cpuFile = *cgroupFS + "/" + cgroup + "/cpu.max";
-
-        auto cpuMax = readFile(cpuFile);
-        auto cpuMaxParts = tokenizeString<std::vector<std::string>>(cpuMax, " \n");
-
-        if (cpuMaxParts.size() != 2) {
-            return 0;
-        }
-
-        auto quota = cpuMaxParts[0];
-        auto period = cpuMaxParts[1];
-        if (quota != "max")
-                return std::ceil(std::stoi(quota) / std::stof(period));
-    } catch (Error &) { ignoreException(lvlDebug); }
-    #endif
-
-    return 0;
-}
-
-rlim_t savedStackSize = 0;
-
-void setStackSize(rlim_t stackSize)
-{
-    struct rlimit limit;
-    if (getrlimit(RLIMIT_STACK, &limit) == 0 && limit.rlim_cur < stackSize) {
-        savedStackSize = limit.rlim_cur;
-        limit.rlim_cur = std::min(stackSize, limit.rlim_max);
-        if (setrlimit(RLIMIT_STACK, &limit) != 0) {
-            logger->log(
-                lvlError,
-                HintFmt(
-                    "Failed to increase stack size from %1% to %2% (maximum allowed stack size: %3%): %4%",
-                    savedStackSize,
-                    stackSize,
-                    limit.rlim_max,
-                    std::strerror(errno)
-                ).str()
-            );
-        }
-    }
-}
-
-void restoreProcessContext(bool restoreMounts)
-{
-    restoreSignals();
-    if (restoreMounts) {
-        restoreMountNamespace();
-    }
-
-    if (savedStackSize) {
-        struct rlimit limit;
-        if (getrlimit(RLIMIT_STACK, &limit) == 0) {
-            limit.rlim_cur = savedStackSize;
-            setrlimit(RLIMIT_STACK, &limit);
-        }
-    }
-}
-
-std::optional<Path> getSelfExe()
-{
-    static auto cached = []() -> std::optional<Path>
-    {
-        #if __linux__
-        return readLink("/proc/self/exe");
-        #elif __APPLE__
-        char buf[1024];
-        uint32_t size = sizeof(buf);
-        if (_NSGetExecutablePath(buf, &size) == 0)
-            return buf;
-        else
-            return std::nullopt;
-        #else
-        return std::nullopt;
-        #endif
-    }();
-    return cached;
-}
-
-}
--- a/src/libutil/current-process.hh
+++ b/src/libutil/current-process.hh
@ -1,37 +0,0 @@
-#pragma once
-///@file
-
-#include <optional>
-#include <sys/resource.h>
-
-#include "types.hh"
-
-namespace nix {
-
-/**
- * If cgroups are active, attempt to calculate the number of CPUs available.
- * If cgroups are unavailable or if cpu.max is set to "max", return 0.
- */
-unsigned int getMaxCPU();
-
-
-/**
- * Change the stack size.
- */
-void setStackSize(rlim_t stackSize);
-
-
-/**
- * Restore the original inherited Unix process context (such as signal
- * masks, stack size).
-
- * See startSignalHandlerThread(), saveSignalMask().
- */
-void restoreProcessContext(bool restoreMounts = true);
-
-/**
- * @return the path of the current executable.
- */
-std::optional<Path> getSelfExe();
-
-}
--- a/src/libutil/environment-variables.cc
+++ b/src/libutil/environment-variables.cc
@ -1,51 +0,0 @@
-#include <cstring>
-#include <map>
-#include <optional>
-#include <string>
-
-extern char * * environ __attribute__((weak));
-
-namespace nix {
-
-std::optional<std::string> getEnv(const std::string & key)
-{
-    char * value = getenv(key.c_str());
-    if (!value) return {};
-    return std::string(value);
-}
-
-std::optional<std::string> getEnvNonEmpty(const std::string & key) {
-    auto value = getEnv(key);
-    if (value == "") return {};
-    return value;
-}
-
-std::map<std::string, std::string> getEnv()
-{
-    std::map<std::string, std::string> env;
-    for (size_t i = 0; environ[i]; ++i) {
-        auto s = environ[i];
-        auto eq = strchr(s, '=');
-        if (!eq)
-            // invalid env, just keep going
-            continue;
-        env.emplace(std::string(s, eq), std::string(eq + 1));
-    }
-    return env;
-}
-
-
-void clearEnv()
-{
-    for (auto & name : getEnv())
-        unsetenv(name.first.c_str());
-}
-
-void replaceEnv(const std::map<std::string, std::string> & newEnv)
-{
-    clearEnv();
-    for (auto & newEnvVar : newEnv)
-        setenv(newEnvVar.first.c_str(), newEnvVar.second.c_str(), 1);
-}
-
-}
--- a/src/libutil/environment-variables.hh
+++ b/src/libutil/environment-variables.hh
@ -1,42 +0,0 @@
-#pragma once
-/**
- * @file
- *
- * Utilities for working with the current process's environment
- * variables.
- */
-
-#include <map>
-#include <optional>
-#include <string>
-
-
-namespace nix {
-
-/**
- * @return an environment variable.
- */
-std::optional<std::string> getEnv(const std::string & key);
-
-/**
- * @return a non empty environment variable. Returns nullopt if the env
- * variable is set to ""
- */
-std::optional<std::string> getEnvNonEmpty(const std::string & key);
-
-/**
- * Get the entire environment.
- */
-std::map<std::string, std::string> getEnv();
-
-/**
- * Clear the environment.
- */
-void clearEnv();
-
-/**
- * Replace the entire environment with the given one.
- */
-void replaceEnv(const std::map<std::string, std::string> & newEnv);
-
-}
--- a/src/libutil/error.cc
+++ b/src/libutil/error.cc
@ -1,15 +1,15 @@
-#include "environment-variables.hh"
 #include "error.hh"
-#include "logging.hh"
 #include "position.hh"
-#include "terminal.hh"

 #include <iostream>
 #include <optional>
+#include "serialise.hh"
 #include <sstream>

 namespace nix {

+const std::string nativeSystem = SYSTEM;
+
 void BaseError::addTrace(std::shared_ptr<Pos> && e, HintFmt hint)
 {
    err.traces.push_front(Trace { .pos = std::move(e), .hint = hint });
@ -415,17 +415,4 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s
    return out;
 }

-void ignoreException(Verbosity lvl)
-{
-    /* Make sure no exceptions leave this function.
-       printError() also throws when remote is closed. */
-    try {
-        try {
-            throw;
-        } catch (std::exception & e) {
-            printMsg(lvl, "error (ignored): %1%", e.what());
-        }
-    } catch (...) { }
-}
-
 }
--- a/src/libutil/error.hh
+++ b/src/libutil/error.hh
@ -202,10 +202,4 @@ public:
    }
 };

-/**
- * Exception handling in destructors: print an error message, then
- * ignore the exception.
- */
-void ignoreException(Verbosity lvl = lvlError);
-
 }
--- a/src/libutil/experimental-features.cc
+++ b/src/libutil/experimental-features.cc
@ -1,7 +1,7 @@
 #include "experimental-features.hh"
 // Required for instances of to_json and from_json for ExperimentalFeature
 #include "experimental-features-json.hh"
-#include "strings.hh"
+#include "util.hh"

 #include "nlohmann/json.hpp"

--- a/src/libutil/file-descriptor.cc
+++ b/src/libutil/file-descriptor.cc
@ -1,252 +0,0 @@
-#include "file-system.hh"
-#include "finally.hh"
-#include "logging.hh"
-#include "serialise.hh"
-#include "signals.hh"
-
-#include <fcntl.h>
-#include <unistd.h>
-
-namespace nix {
-
-std::string readFile(int fd)
-{
-    struct stat st;
-    if (fstat(fd, &st) == -1)
-        throw SysError("statting file");
-
-    return drainFD(fd, true, st.st_size);
-}
-
-
-std::string readLine(int fd)
-{
-    std::string s;
-    while (1) {
-        checkInterrupt();
-        char ch;
-        // FIXME: inefficient
-        ssize_t rd = read(fd, &ch, 1);
-        if (rd == -1) {
-            if (errno != EINTR)
-                throw SysError("reading a line");
-        } else if (rd == 0)
-            throw EndOfFile("unexpected EOF reading a line");
-        else {
-            if (ch == '\n') return s;
-            s += ch;
-        }
-    }
-}
-
-
-void writeLine(int fd, std::string s)
-{
-    s += '\n';
-    writeFull(fd, s);
-}
-
-
-void readFull(int fd, char * buf, size_t count)
-{
-    while (count) {
-        checkInterrupt();
-        ssize_t res = read(fd, buf, count);
-        if (res == -1) {
-            if (errno == EINTR) continue;
-            throw SysError("reading from file");
-        }
-        if (res == 0) throw EndOfFile("unexpected end-of-file");
-        count -= res;
-        buf += res;
-    }
-}
-
-
-void writeFull(int fd, std::string_view s, bool allowInterrupts)
-{
-    while (!s.empty()) {
-        if (allowInterrupts) checkInterrupt();
-        ssize_t res = write(fd, s.data(), s.size());
-        if (res == -1 && errno != EINTR)
-            throw SysError("writing to file");
-        if (res > 0)
-            s.remove_prefix(res);
-    }
-}
-
-
-std::string drainFD(int fd, bool block, const size_t reserveSize)
-{
-    // the parser needs two extra bytes to append terminating characters, other users will
-    // not care very much about the extra memory.
-    StringSink sink(reserveSize + 2);
-    drainFD(fd, sink, block);
-    return std::move(sink.s);
-}
-
-
-void drainFD(int fd, Sink & sink, bool block)
-{
-    // silence GCC maybe-uninitialized warning in finally
-    int saved = 0;
-
-    if (!block) {
-        saved = fcntl(fd, F_GETFL);
-        if (fcntl(fd, F_SETFL, saved | O_NONBLOCK) == -1)
-            throw SysError("making file descriptor non-blocking");
-    }
-
-    Finally finally([&]() {
-        if (!block) {
-            if (fcntl(fd, F_SETFL, saved) == -1)
-                throw SysError("making file descriptor blocking");
-        }
-    });
-
-    std::array<unsigned char, 64 * 1024> buf;
-    while (1) {
-        checkInterrupt();
-        ssize_t rd = read(fd, buf.data(), buf.size());
-        if (rd == -1) {
-            if (!block && (errno == EAGAIN || errno == EWOULDBLOCK))
-                break;
-            if (errno != EINTR)
-                throw SysError("reading from file");
-        }
-        else if (rd == 0) break;
-        else sink({(char *) buf.data(), (size_t) rd});
-    }
-}
-
-AutoCloseFD::AutoCloseFD() : fd{-1} {}
-
-
-AutoCloseFD::AutoCloseFD(int fd) : fd{fd} {}
-
-
-AutoCloseFD::AutoCloseFD(AutoCloseFD && that) : fd{that.fd}
-{
-    that.fd = -1;
-}
-
-
-AutoCloseFD & AutoCloseFD::operator =(AutoCloseFD && that)
-{
-    close();
-    fd = that.fd;
-    that.fd = -1;
-    return *this;
-}
-
-
-AutoCloseFD::~AutoCloseFD()
-{
-    try {
-        close();
-    } catch (...) {
-        ignoreException();
-    }
-}
-
-
-int AutoCloseFD::get() const
-{
-    return fd;
-}
-
-
-void AutoCloseFD::close()
-{
-    if (fd != -1) {
-        if (::close(fd) == -1)
-            /* This should never happen. */
-            throw SysError("closing file descriptor %1%", fd);
-        fd = -1;
-    }
-}
-
-void AutoCloseFD::fsync()
-{
-  if (fd != -1) {
-      int result;
-#if __APPLE__
-      result = ::fcntl(fd, F_FULLFSYNC);
-#else
-      result = ::fsync(fd);
-#endif
-      if (result == -1)
-          throw SysError("fsync file descriptor %1%", fd);
-  }
-}
-
-
-AutoCloseFD::operator bool() const
-{
-    return fd != -1;
-}
-
-
-int AutoCloseFD::release()
-{
-    int oldFD = fd;
-    fd = -1;
-    return oldFD;
-}
-
-
-void Pipe::create()
-{
-    int fds[2];
-#if HAVE_PIPE2
-    if (pipe2(fds, O_CLOEXEC) != 0) throw SysError("creating pipe");
-#else
-    if (pipe(fds) != 0) throw SysError("creating pipe");
-    closeOnExec(fds[0]);
-    closeOnExec(fds[1]);
-#endif
-    readSide = AutoCloseFD{fds[0]};
-    writeSide = AutoCloseFD{fds[1]};
-}
-
-
-void Pipe::close()
-{
-    readSide.close();
-    writeSide.close();
-}
-
-
-void closeMostFDs(const std::set<int> & exceptions)
-{
-#if __linux__
-    try {
-        for (auto & s : readDirectory("/proc/self/fd")) {
-            auto fd = std::stoi(s.name);
-            if (!exceptions.count(fd)) {
-                debug("closing leaked FD %d", fd);
-                close(fd);
-            }
-        }
-        return;
-    } catch (SysError &) {
-    }
-#endif
-
-    int maxFD = 0;
-    maxFD = sysconf(_SC_OPEN_MAX);
-    for (int fd = 0; fd < maxFD; ++fd)
-        if (!exceptions.count(fd))
-            close(fd); /* ignore result */
-}
-
-
-void closeOnExec(int fd)
-{
-    int prev;
-    if ((prev = fcntl(fd, F_GETFD, 0)) == -1 ||
-        fcntl(fd, F_SETFD, prev | FD_CLOEXEC) == -1)
-        throw SysError("setting close-on-exec flag");
-}
-
-}
--- a/src/libutil/file-descriptor.hh
+++ b/src/libutil/file-descriptor.hh
@ -1,80 +0,0 @@
-#pragma once
-///@file
-
-#include "error.hh"
-
-namespace nix {
-
-struct Sink;
-struct Source;
-
-/**
- * Read a line from a file descriptor.
- */
-std::string readLine(int fd);
-
-/**
- * Write a line to a file descriptor.
- */
-void writeLine(int fd, std::string s);
-
-/**
- * Read the contents of a file into a string.
- */
-std::string readFile(int fd);
-
-/**
- * Wrappers arount read()/write() that read/write exactly the
- * requested number of bytes.
- */
-void readFull(int fd, char * buf, size_t count);
-void writeFull(int fd, std::string_view s, bool allowInterrupts = true);
-
-/**
- * Read a file descriptor until EOF occurs.
- */
-std::string drainFD(int fd, bool block = true, const size_t reserveSize=0);
-
-void drainFD(int fd, Sink & sink, bool block = true);
-
-class AutoCloseFD
-{
-    int fd;
-public:
-    AutoCloseFD();
-    explicit AutoCloseFD(int fd);
-    AutoCloseFD(const AutoCloseFD & fd) = delete;
-    AutoCloseFD(AutoCloseFD&& fd);
-    ~AutoCloseFD();
-    AutoCloseFD& operator =(const AutoCloseFD & fd) = delete;
-    AutoCloseFD& operator =(AutoCloseFD&& fd) noexcept(false);
-    int get() const;
-    explicit operator bool() const;
-    int release();
-    void close();
-    void fsync();
-    void reset() { *this = {}; }
-};
-
-class Pipe
-{
-public:
-    AutoCloseFD readSide, writeSide;
-    void create();
-    void close();
-};
-
-/**
- * Close all file descriptors except those listed in the given set.
- * Good practice in child processes.
- */
-void closeMostFDs(const std::set<int> & exceptions);
-
-/**
- * Set the close-on-exec flag for the given file descriptor.
- */
-void closeOnExec(int fd);
-
-MakeError(EndOfFile, Error);
-
-}
--- a/src/libutil/file-system.cc
+++ b/src/libutil/file-system.cc
@ -1,670 +0,0 @@
-#include <sys/time.h>
-#include <filesystem>
-#include <atomic>
-
-#include "environment-variables.hh"
-#include "file-descriptor.hh"
-#include "file-system.hh"
-#include "finally.hh"
-#include "logging.hh"
-#include "serialise.hh"
-#include "signals.hh"
-#include "types.hh"
-#include "users.hh"
-
-namespace fs = std::filesystem;
-
-namespace nix {
-
-Path absPath(Path path, std::optional<PathView> dir, bool resolveSymlinks)
-{
-    if (path.empty() || path[0] != '/') {
-        if (!dir) {
-#ifdef __GNU__
-            /* GNU (aka. GNU/Hurd) doesn't have any limitation on path
-               lengths and doesn't define `PATH_MAX'.  */
-            char *buf = getcwd(NULL, 0);
-            if (buf == NULL)
-#else
-            char buf[PATH_MAX];
-            if (!getcwd(buf, sizeof(buf)))
-#endif
-                throw SysError("cannot get cwd");
-            path = concatStrings(buf, "/", path);
-#ifdef __GNU__
-            free(buf);
-#endif
-        } else
-            path = concatStrings(*dir, "/", path);
-    }
-    return canonPath(path, resolveSymlinks);
-}
-
-
-Path canonPath(PathView path, bool resolveSymlinks)
-{
-    assert(path != "");
-
-    std::string s;
-    s.reserve(256);
-
-    if (path[0] != '/')
-        throw Error("not an absolute path: '%1%'", path);
-
-    std::string temp;
-
-    /* Count the number of times we follow a symlink and stop at some
-       arbitrary (but high) limit to prevent infinite loops. */
-    unsigned int followCount = 0, maxFollow = 1024;
-
-    while (1) {
-
-        /* Skip slashes. */
-        while (!path.empty() && path[0] == '/') path.remove_prefix(1);
-        if (path.empty()) break;
-
-        /* Ignore `.'. */
-        if (path == "." || path.substr(0, 2) == "./")
-            path.remove_prefix(1);
-
-        /* If `..', delete the last component. */
-        else if (path == ".." || path.substr(0, 3) == "../")
-        {
-            if (!s.empty()) s.erase(s.rfind('/'));
-            path.remove_prefix(2);
-        }
-
-        /* Normal component; copy it. */
-        else {
-            s += '/';
-            if (const auto slash = path.find('/'); slash == std::string::npos) {
-                s += path;
-                path = {};
-            } else {
-                s += path.substr(0, slash);
-                path = path.substr(slash);
-            }
-
-            /* If s points to a symlink, resolve it and continue from there */
-            if (resolveSymlinks && isLink(s)) {
-                if (++followCount >= maxFollow)
-                    throw Error("infinite symlink recursion in path '%1%'", path);
-                temp = concatStrings(readLink(s), path);
-                path = temp;
-                if (!temp.empty() && temp[0] == '/') {
-                    s.clear();  /* restart for symlinks pointing to absolute path */
-                } else {
-                    s = dirOf(s);
-                    if (s == "/") {  // we don’t want trailing slashes here, which dirOf only produces if s = /
-                        s.clear();
-                    }
-                }
-            }
-        }
-    }
-
-    return s.empty() ? "/" : std::move(s);
-}
-
-void chmodPath(const Path & path, mode_t mode)
-{
-    if (chmod(path.c_str(), mode) == -1)
-        throw SysError("setting permissions on '%s'", path);
-}
-
-Path dirOf(const PathView path)
-{
-    Path::size_type pos = path.rfind('/');
-    if (pos == std::string::npos)
-        return ".";
-    return pos == 0 ? "/" : Path(path, 0, pos);
-}
-
-
-std::string_view baseNameOf(std::string_view path)
-{
-    if (path.empty())
-        return "";
-
-    auto last = path.size() - 1;
-    if (path[last] == '/' && last > 0)
-        last -= 1;
-
-    auto pos = path.rfind('/', last);
-    if (pos == std::string::npos)
-        pos = 0;
-    else
-        pos += 1;
-
-    return path.substr(pos, last - pos + 1);
-}
-
-
-std::string expandTilde(std::string_view path)
-{
-    // TODO: expand ~user ?
-    auto tilde = path.substr(0, 2);
-    if (tilde == "~/" || tilde == "~")
-        return getHome() + std::string(path.substr(1));
-    else
-        return std::string(path);
-}
-
-
-bool isInDir(std::string_view path, std::string_view dir)
-{
-    return path.substr(0, 1) == "/"
-        && path.substr(0, dir.size()) == dir
-        && path.size() >= dir.size() + 2
-        && path[dir.size()] == '/';
-}
-
-
-bool isDirOrInDir(std::string_view path, std::string_view dir)
-{
-    return path == dir || isInDir(path, dir);
-}
-
-
-struct stat stat(const Path & path)
-{
-    struct stat st;
-    if (stat(path.c_str(), &st))
-        throw SysError("getting status of '%1%'", path);
-    return st;
-}
-
-
-struct stat lstat(const Path & path)
-{
-    struct stat st;
-    if (lstat(path.c_str(), &st))
-        throw SysError("getting status of '%1%'", path);
-    return st;
-}
-
-std::optional<struct stat> maybeLstat(const Path & path)
-{
-    std::optional<struct stat> st{std::in_place};
-    if (lstat(path.c_str(), &*st))
-    {
-        if (errno == ENOENT || errno == ENOTDIR)
-            st.reset();
-        else
-            throw SysError("getting status of '%s'", path);
-    }
-    return st;
-}
-
-bool pathExists(const Path & path)
-{
-    return maybeLstat(path).has_value();
-}
-
-bool pathAccessible(const Path & path)
-{
-    try {
-        return pathExists(path);
-    } catch (SysError & e) {
-        // swallow EPERM
-        if (e.errNo == EPERM) return false;
-        throw;
-    }
-}
-
-
-Path readLink(const Path & path)
-{
-    checkInterrupt();
-    std::vector<char> buf;
-    for (ssize_t bufSize = PATH_MAX/4; true; bufSize += bufSize/2) {
-        buf.resize(bufSize);
-        ssize_t rlSize = readlink(path.c_str(), buf.data(), bufSize);
-        if (rlSize == -1)
-            if (errno == EINVAL)
-                throw Error("'%1%' is not a symlink", path);
-            else
-                throw SysError("reading symbolic link '%1%'", path);
-        else if (rlSize < bufSize)
-            return std::string(buf.data(), rlSize);
-    }
-}
-
-
-bool isLink(const Path & path)
-{
-    struct stat st = lstat(path);
-    return S_ISLNK(st.st_mode);
-}
-
-
-DirEntries readDirectory(DIR *dir, const Path & path)
-{
-    DirEntries entries;
-    entries.reserve(64);
-
-    struct dirent * dirent;
-    while (errno = 0, dirent = readdir(dir)) { /* sic */
-        checkInterrupt();
-        std::string name = dirent->d_name;
-        if (name == "." || name == "..") continue;
-        entries.emplace_back(name, dirent->d_ino,
-#ifdef HAVE_STRUCT_DIRENT_D_TYPE
-            dirent->d_type
-#else
-            DT_UNKNOWN
-#endif
-        );
-    }
-    if (errno) throw SysError("reading directory '%1%'", path);
-
-    return entries;
-}
-
-DirEntries readDirectory(const Path & path)
-{
-    AutoCloseDir dir(opendir(path.c_str()));
-    if (!dir) throw SysError("opening directory '%1%'", path);
-
-    return readDirectory(dir.get(), path);
-}
-
-
-unsigned char getFileType(const Path & path)
-{
-    struct stat st = lstat(path);
-    if (S_ISDIR(st.st_mode)) return DT_DIR;
-    if (S_ISLNK(st.st_mode)) return DT_LNK;
-    if (S_ISREG(st.st_mode)) return DT_REG;
-    return DT_UNKNOWN;
-}
-
-
-std::string readFile(const Path & path)
-{
-    AutoCloseFD fd{open(path.c_str(), O_RDONLY | O_CLOEXEC)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-    return readFile(fd.get());
-}
-
-
-void readFile(const Path & path, Sink & sink)
-{
-    AutoCloseFD fd{open(path.c_str(), O_RDONLY | O_CLOEXEC)};
-    if (!fd)
-        throw SysError("opening file '%s'", path);
-    drainFD(fd.get(), sink);
-}
-
-
-void writeFile(const Path & path, std::string_view s, mode_t mode, bool sync)
-{
-    AutoCloseFD fd{open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-    try {
-        writeFull(fd.get(), s);
-    } catch (Error & e) {
-        e.addTrace({}, "writing file '%1%'", path);
-        throw;
-    }
-    if (sync)
-        fd.fsync();
-    // Explicitly close to make sure exceptions are propagated.
-    fd.close();
-    if (sync)
-        syncParent(path);
-}
-
-
-void writeFile(const Path & path, Source & source, mode_t mode, bool sync)
-{
-    AutoCloseFD fd{open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-
-    std::vector<char> buf(64 * 1024);
-
-    try {
-        while (true) {
-            try {
-                auto n = source.read(buf.data(), buf.size());
-                writeFull(fd.get(), {buf.data(), n});
-            } catch (EndOfFile &) { break; }
-        }
-    } catch (Error & e) {
-        e.addTrace({}, "writing file '%1%'", path);
-        throw;
-    }
-    if (sync)
-        fd.fsync();
-    // Explicitly close to make sure exceptions are propagated.
-    fd.close();
-    if (sync)
-        syncParent(path);
-}
-
-void syncParent(const Path & path)
-{
-    AutoCloseFD fd{open(dirOf(path).c_str(), O_RDONLY, 0)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-    fd.fsync();
-}
-
-static void _deletePath(int parentfd, const Path & path, uint64_t & bytesFreed)
-{
-    checkInterrupt();
-
-    std::string name(baseNameOf(path));
-
-    struct stat st;
-    if (fstatat(parentfd, name.c_str(), &st, AT_SYMLINK_NOFOLLOW) == -1) {
-        if (errno == ENOENT) return;
-        throw SysError("getting status of '%1%'", path);
-    }
-
-    if (!S_ISDIR(st.st_mode)) {
-        /* We are about to delete a file. Will it likely free space? */
-
-        switch (st.st_nlink) {
-            /* Yes: last link. */
-            case 1:
-                bytesFreed += st.st_size;
-                break;
-            /* Maybe: yes, if 'auto-optimise-store' or manual optimisation
-               was performed. Instead of checking for real let's assume
-               it's an optimised file and space will be freed.
-
-               In worst case we will double count on freed space for files
-               with exactly two hardlinks for unoptimised packages.
-             */
-            case 2:
-                bytesFreed += st.st_size;
-                break;
-            /* No: 3+ links. */
-            default:
-                break;
-        }
-    }
-
-    if (S_ISDIR(st.st_mode)) {
-        /* Make the directory accessible. */
-        const auto PERM_MASK = S_IRUSR | S_IWUSR | S_IXUSR;
-        if ((st.st_mode & PERM_MASK) != PERM_MASK) {
-            if (fchmodat(parentfd, name.c_str(), st.st_mode | PERM_MASK, 0) == -1)
-                throw SysError("chmod '%1%'", path);
-        }
-
-        int fd = openat(parentfd, path.c_str(), O_RDONLY);
-        if (fd == -1)
-            throw SysError("opening directory '%1%'", path);
-        AutoCloseDir dir(fdopendir(fd));
-        if (!dir)
-            throw SysError("opening directory '%1%'", path);
-        for (auto & i : readDirectory(dir.get(), path))
-            _deletePath(dirfd(dir.get()), path + "/" + i.name, bytesFreed);
-    }
-
-    int flags = S_ISDIR(st.st_mode) ? AT_REMOVEDIR : 0;
-    if (unlinkat(parentfd, name.c_str(), flags) == -1) {
-        if (errno == ENOENT) return;
-        throw SysError("cannot unlink '%1%'", path);
-    }
-}
-
-static void _deletePath(const Path & path, uint64_t & bytesFreed)
-{
-    Path dir = dirOf(path);
-    if (dir == "")
-        dir = "/";
-
-    AutoCloseFD dirfd{open(dir.c_str(), O_RDONLY)};
-    if (!dirfd) {
-        if (errno == ENOENT) return;
-        throw SysError("opening directory '%1%'", path);
-    }
-
-    _deletePath(dirfd.get(), path, bytesFreed);
-}
-
-
-void deletePath(const Path & path)
-{
-    uint64_t dummy;
-    deletePath(path, dummy);
-}
-
-
-void deletePath(const Path & path, uint64_t & bytesFreed)
-{
-    //Activity act(*logger, lvlDebug, "recursively deleting path '%1%'", path);
-    bytesFreed = 0;
-    _deletePath(path, bytesFreed);
-}
-
-Paths createDirs(const Path & path)
-{
-    Paths created;
-    if (path == "/") return created;
-
-    struct stat st;
-    if (lstat(path.c_str(), &st) == -1) {
-        created = createDirs(dirOf(path));
-        if (mkdir(path.c_str(), 0777) == -1 && errno != EEXIST)
-            throw SysError("creating directory '%1%'", path);
-        st = lstat(path);
-        created.push_back(path);
-    }
-
-    if (S_ISLNK(st.st_mode) && stat(path.c_str(), &st) == -1)
-        throw SysError("statting symlink '%1%'", path);
-
-    if (!S_ISDIR(st.st_mode)) throw Error("'%1%' is not a directory", path);
-
-    return created;
-}
-
-
-//////////////////////////////////////////////////////////////////////
-
-AutoDelete::AutoDelete() : del{false} {}
-
-AutoDelete::AutoDelete(const std::string & p, bool recursive) : path(p)
-{
-    del = true;
-    this->recursive = recursive;
-}
-
-AutoDelete::~AutoDelete()
-{
-    try {
-        if (del) {
-            if (recursive)
-                deletePath(path);
-            else {
-                if (remove(path.c_str()) == -1)
-                    throw SysError("cannot unlink '%1%'", path);
-            }
-        }
-    } catch (...) {
-        ignoreException();
-    }
-}
-
-void AutoDelete::cancel()
-{
-    del = false;
-}
-
-void AutoDelete::reset(const Path & p, bool recursive) {
-    path = p;
-    this->recursive = recursive;
-    del = true;
-}
-
-//////////////////////////////////////////////////////////////////////
-
-static Path tempName(Path tmpRoot, const Path & prefix, bool includePid,
-    std::atomic<unsigned int> & counter)
-{
-    tmpRoot = canonPath(tmpRoot.empty() ? getEnv("TMPDIR").value_or("/tmp") : tmpRoot, true);
-    if (includePid)
-        return fmt("%1%/%2%-%3%-%4%", tmpRoot, prefix, getpid(), counter++);
-    else
-        return fmt("%1%/%2%-%3%", tmpRoot, prefix, counter++);
-}
-
-Path createTempDir(const Path & tmpRoot, const Path & prefix,
-    bool includePid, bool useGlobalCounter, mode_t mode)
-{
-    static std::atomic<unsigned int> globalCounter = 0;
-    std::atomic<unsigned int> localCounter = 0;
-    auto & counter(useGlobalCounter ? globalCounter : localCounter);
-
-    while (1) {
-        checkInterrupt();
-        Path tmpDir = tempName(tmpRoot, prefix, includePid, counter);
-        if (mkdir(tmpDir.c_str(), mode) == 0) {
-#if __FreeBSD__
-            /* Explicitly set the group of the directory.  This is to
-               work around around problems caused by BSD's group
-               ownership semantics (directories inherit the group of
-               the parent).  For instance, the group of /tmp on
-               FreeBSD is "wheel", so all directories created in /tmp
-               will be owned by "wheel"; but if the user is not in
-               "wheel", then "tar" will fail to unpack archives that
-               have the setgid bit set on directories. */
-            if (chown(tmpDir.c_str(), (uid_t) -1, getegid()) != 0)
-                throw SysError("setting group of directory '%1%'", tmpDir);
-#endif
-            return tmpDir;
-        }
-        if (errno != EEXIST)
-            throw SysError("creating directory '%1%'", tmpDir);
-    }
-}
-
-
-std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)
-{
-    Path tmpl(getEnv("TMPDIR").value_or("/tmp") + "/" + prefix + ".XXXXXX");
-    // Strictly speaking, this is UB, but who cares...
-    // FIXME: use O_TMPFILE.
-    AutoCloseFD fd(mkstemp((char *) tmpl.c_str()));
-    if (!fd)
-        throw SysError("creating temporary file '%s'", tmpl);
-    closeOnExec(fd.get());
-    return {std::move(fd), tmpl};
-}
-
-void createSymlink(const Path & target, const Path & link)
-{
-    if (symlink(target.c_str(), link.c_str()))
-        throw SysError("creating symlink from '%1%' to '%2%'", link, target);
-}
-
-void replaceSymlink(const Path & target, const Path & link)
-{
-    for (unsigned int n = 0; true; n++) {
-        Path tmp = canonPath(fmt("%s/.%d_%s", dirOf(link), n, baseNameOf(link)));
-
-        try {
-            createSymlink(target, tmp);
-        } catch (SysError & e) {
-            if (e.errNo == EEXIST) continue;
-            throw;
-        }
-
-        renameFile(tmp, link);
-
-        break;
-    }
-}
-
-void setWriteTime(const fs::path & p, const struct stat & st)
-{
-    struct timeval times[2];
-    times[0] = {
-        .tv_sec = st.st_atime,
-        .tv_usec = 0,
-    };
-    times[1] = {
-        .tv_sec = st.st_mtime,
-        .tv_usec = 0,
-    };
-    if (lutimes(p.c_str(), times) != 0)
-        throw SysError("changing modification time of '%s'", p);
-}
-
-void copy(const fs::directory_entry & from, const fs::path & to, CopyFileFlags flags)
-{
-    // TODO: Rewrite the `is_*` to use `symlink_status()`
-    auto statOfFrom = lstat(from.path().c_str());
-    auto fromStatus = from.symlink_status();
-
-    // Mark the directory as writable so that we can delete its children
-    if (flags.deleteAfter && fs::is_directory(fromStatus)) {
-        fs::permissions(from.path(), fs::perms::owner_write, fs::perm_options::add | fs::perm_options::nofollow);
-    }
-
-
-    if (fs::is_symlink(fromStatus) || fs::is_regular_file(fromStatus)) {
-        auto opts = fs::copy_options::overwrite_existing;
-
-        if (!flags.followSymlinks) {
-            opts |= fs::copy_options::copy_symlinks;
-        }
-
-        fs::copy(from.path(), to, opts);
-    } else if (fs::is_directory(fromStatus)) {
-        fs::create_directory(to);
-        for (auto & entry : fs::directory_iterator(from.path())) {
-            copy(entry, to / entry.path().filename(), flags);
-        }
-    } else {
-        throw Error("file '%s' has an unsupported type", from.path());
-    }
-
-    setWriteTime(to, statOfFrom);
-    if (flags.deleteAfter) {
-        if (!fs::is_symlink(fromStatus))
-            fs::permissions(from.path(), fs::perms::owner_write, fs::perm_options::add | fs::perm_options::nofollow);
-        fs::remove(from.path());
-    }
-}
-
-
-void copyFile(const Path & oldPath, const Path & newPath, CopyFileFlags flags)
-{
-    return copy(fs::directory_entry(fs::path(oldPath)), fs::path(newPath), flags);
-}
-
-void renameFile(const Path & oldName, const Path & newName)
-{
-    fs::rename(oldName, newName);
-}
-
-void moveFile(const Path & oldName, const Path & newName)
-{
-    try {
-        renameFile(oldName, newName);
-    } catch (fs::filesystem_error & e) {
-        auto oldPath = fs::path(oldName);
-        auto newPath = fs::path(newName);
-        // For the move to be as atomic as possible, copy to a temporary
-        // directory
-        fs::path temp = createTempDir(newPath.parent_path(), "rename-tmp");
-        Finally removeTemp = [&]() { fs::remove(temp); };
-        auto tempCopyTarget = temp / "copy-target";
-        if (e.code().value() == EXDEV) {
-            fs::remove(newPath);
-            warn("Can’t rename %s as %s, copying instead", oldName, newName);
-            copy(fs::directory_entry(oldPath), tempCopyTarget, { .deleteAfter = true });
-            renameFile(tempCopyTarget, newPath);
-        }
-    }
-}
-
-}
--- a/src/libutil/file-system.hh
+++ b/src/libutil/file-system.hh
@ -1,269 +0,0 @@
-#pragma once
-/**
- * @file
- *
- * Utiltities for working with the file sytem and file paths.
- */
-
-#include "types.hh"
-#include "file-descriptor.hh"
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <dirent.h>
-#include <unistd.h>
-
-#include <boost/lexical_cast.hpp>
-
-#include <functional>
-#include <optional>
-
-#ifndef HAVE_STRUCT_DIRENT_D_TYPE
-#define DT_UNKNOWN 0
-#define DT_REG 1
-#define DT_LNK 2
-#define DT_DIR 3
-#endif
-
-namespace nix {
-
-struct Sink;
-struct Source;
-
-/**
- * @return An absolutized path, resolving paths relative to the
- * specified directory, or the current directory otherwise.  The path
- * is also canonicalised.
- */
-Path absPath(Path path,
-    std::optional<PathView> dir = {},
-    bool resolveSymlinks = false);
-
-/**
- * Canonicalise a path by removing all `.` or `..` components and
- * double or trailing slashes.  Optionally resolves all symlink
- * components such that each component of the resulting path is *not*
- * a symbolic link.
- */
-Path canonPath(PathView path, bool resolveSymlinks = false);
-
-/**
- * Change the permissions of a path
- * Not called `chmod` as it shadows and could be confused with
- * `int chmod(char *, mode_t)`, which does not handle errors
- */
-void chmodPath(const Path & path, mode_t mode);
-
-/**
- * @return The directory part of the given canonical path, i.e.,
- * everything before the final `/`.  If the path is the root or an
- * immediate child thereof (e.g., `/foo`), this means `/`
- * is returned.
- */
-Path dirOf(const PathView path);
-
-/**
- * @return the base name of the given canonical path, i.e., everything
- * following the final `/` (trailing slashes are removed).
- */
-std::string_view baseNameOf(std::string_view path);
-
-/**
- * Perform tilde expansion on a path.
- */
-std::string expandTilde(std::string_view path);
-
-/**
- * Check whether 'path' is a descendant of 'dir'. Both paths must be
- * canonicalized.
- */
-bool isInDir(std::string_view path, std::string_view dir);
-
-/**
- * Check whether 'path' is equal to 'dir' or a descendant of
- * 'dir'. Both paths must be canonicalized.
- */
-bool isDirOrInDir(std::string_view path, std::string_view dir);
-
-/**
- * Get status of `path`.
- */
-struct stat stat(const Path & path);
-struct stat lstat(const Path & path);
-
-/**
- * `lstat` the given path if it exists.
- * @return std::nullopt if the path doesn't exist, or an optional containing the result of `lstat` otherwise
- */
-std::optional<struct stat> maybeLstat(const Path & path);
-
-/**
- * @return true iff the given path exists.
- */
-bool pathExists(const Path & path);
-
-/**
- * A version of pathExists that returns false on a permission error.
- * Useful for inferring default paths across directories that might not
- * be readable.
- * @return true iff the given path can be accessed and exists
- */
-bool pathAccessible(const Path & path);
-
-/**
- * Read the contents (target) of a symbolic link.  The result is not
- * in any way canonicalised.
- */
-Path readLink(const Path & path);
-
-bool isLink(const Path & path);
-
-/**
- * Read the contents of a directory.  The entries `.` and `..` are
- * removed.
- */
-struct DirEntry
-{
-    std::string name;
-    ino_t ino;
-    /**
-     * one of DT_*
-     */
-    unsigned char type;
-    DirEntry(std::string name, ino_t ino, unsigned char type)
-        : name(std::move(name)), ino(ino), type(type) { }
-};
-
-typedef std::vector<DirEntry> DirEntries;
-
-DirEntries readDirectory(const Path & path);
-
-unsigned char getFileType(const Path & path);
-
-/**
- * Read the contents of a file into a string.
- */
-std::string readFile(const Path & path);
-void readFile(const Path & path, Sink & sink);
-
-/**
- * Write a string to a file.
- */
-void writeFile(const Path & path, std::string_view s, mode_t mode = 0666, bool sync = false);
-
-void writeFile(const Path & path, Source & source, mode_t mode = 0666, bool sync = false);
-
-/**
- * Flush a file's parent directory to disk
- */
-void syncParent(const Path & path);
-
-/**
- * Delete a path; i.e., in the case of a directory, it is deleted
- * recursively. It's not an error if the path does not exist. The
- * second variant returns the number of bytes and blocks freed.
- */
-void deletePath(const Path & path);
-
-void deletePath(const Path & path, uint64_t & bytesFreed);
-
-/**
- * Create a directory and all its parents, if necessary.  Returns the
- * list of created directories, in order of creation.
- */
-Paths createDirs(const Path & path);
-inline Paths createDirs(PathView path)
-{
-    return createDirs(Path(path));
-}
-
-/**
- * Create a symlink.
- */
-void createSymlink(const Path & target, const Path & link);
-
-/**
- * Atomically create or replace a symlink.
- */
-void replaceSymlink(const Path & target, const Path & link);
-
-void renameFile(const Path & src, const Path & dst);
-
-/**
- * Similar to 'renameFile', but fallback to a copy+remove if `src` and `dst`
- * are on a different filesystem.
- *
- * Beware that this might not be atomic because of the copy that happens behind
- * the scenes
- */
-void moveFile(const Path & src, const Path & dst);
-
-struct CopyFileFlags
-{
-    /**
-     * Delete the file after copying.
-     */
-    bool deleteAfter = false;
-
-    /**
-     * Follow symlinks and copy the eventual target.
-     */
-    bool followSymlinks = false;
-};
-
-/**
- * Recursively copy the content of `oldPath` to `newPath`. If `andDelete` is
- * `true`, then also remove `oldPath` (making this equivalent to `moveFile`, but
- * with the guaranty that the destination will be “fresh”, with no stale inode
- * or file descriptor pointing to it).
- */
-void copyFile(const Path & oldPath, const Path & newPath, CopyFileFlags flags);
-
-/**
- * Automatic cleanup of resources.
- */
-
-
-class AutoDelete
-{
-    Path path;
-    bool del;
-    bool recursive;
-public:
-    AutoDelete();
-    AutoDelete(const Path & p, bool recursive = true);
-    ~AutoDelete();
-    void cancel();
-    void reset(const Path & p, bool recursive = true);
-    operator Path() const { return path; }
-    operator PathView() const { return path; }
-};
-
-struct DIRDeleter
-{
-    void operator()(DIR * dir) const {
-        closedir(dir);
-    }
-};
-
-typedef std::unique_ptr<DIR, DIRDeleter> AutoCloseDir;
-
-/**
- * Create a temporary directory.
- */
-Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",
-    bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755);
-
-/**
- * Create a temporary file, returning a file handle and its path.
- */
-std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix = "nix");
-
-/**
- * Used in various places.
- */
-typedef std::function<bool(const Path & path)> PathFilter;
-
-extern PathFilter defaultPathFilter;
-
-}
--- a/src/libutil/filesystem.cc
+++ b/src/libutil/filesystem.cc
@ -0,0 +1,175 @@
+#include <sys/time.h>
+#include <filesystem>
+#include <atomic>
+
+#include "finally.hh"
+#include "util.hh"
+#include "signals.hh"
+#include "types.hh"
+
+namespace fs = std::filesystem;
+
+namespace nix {
+
+static Path tempName(Path tmpRoot, const Path & prefix, bool includePid,
+    std::atomic<unsigned int> & counter)
+{
+    tmpRoot = canonPath(tmpRoot.empty() ? getEnv("TMPDIR").value_or("/tmp") : tmpRoot, true);
+    if (includePid)
+        return fmt("%1%/%2%-%3%-%4%", tmpRoot, prefix, getpid(), counter++);
+    else
+        return fmt("%1%/%2%-%3%", tmpRoot, prefix, counter++);
+}
+
+Path createTempDir(const Path & tmpRoot, const Path & prefix,
+    bool includePid, bool useGlobalCounter, mode_t mode)
+{
+    static std::atomic<unsigned int> globalCounter = 0;
+    std::atomic<unsigned int> localCounter = 0;
+    auto & counter(useGlobalCounter ? globalCounter : localCounter);
+
+    while (1) {
+        checkInterrupt();
+        Path tmpDir = tempName(tmpRoot, prefix, includePid, counter);
+        if (mkdir(tmpDir.c_str(), mode) == 0) {
+#if __FreeBSD__
+            /* Explicitly set the group of the directory.  This is to
+               work around around problems caused by BSD's group
+               ownership semantics (directories inherit the group of
+               the parent).  For instance, the group of /tmp on
+               FreeBSD is "wheel", so all directories created in /tmp
+               will be owned by "wheel"; but if the user is not in
+               "wheel", then "tar" will fail to unpack archives that
+               have the setgid bit set on directories. */
+            if (chown(tmpDir.c_str(), (uid_t) -1, getegid()) != 0)
+                throw SysError("setting group of directory '%1%'", tmpDir);
+#endif
+            return tmpDir;
+        }
+        if (errno != EEXIST)
+            throw SysError("creating directory '%1%'", tmpDir);
+    }
+}
+
+
+std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)
+{
+    Path tmpl(getEnv("TMPDIR").value_or("/tmp") + "/" + prefix + ".XXXXXX");
+    // Strictly speaking, this is UB, but who cares...
+    // FIXME: use O_TMPFILE.
+    AutoCloseFD fd(mkstemp((char *) tmpl.c_str()));
+    if (!fd)
+        throw SysError("creating temporary file '%s'", tmpl);
+    closeOnExec(fd.get());
+    return {std::move(fd), tmpl};
+}
+
+void createSymlink(const Path & target, const Path & link)
+{
+    if (symlink(target.c_str(), link.c_str()))
+        throw SysError("creating symlink from '%1%' to '%2%'", link, target);
+}
+
+void replaceSymlink(const Path & target, const Path & link)
+{
+    for (unsigned int n = 0; true; n++) {
+        Path tmp = canonPath(fmt("%s/.%d_%s", dirOf(link), n, baseNameOf(link)));
+
+        try {
+            createSymlink(target, tmp);
+        } catch (SysError & e) {
+            if (e.errNo == EEXIST) continue;
+            throw;
+        }
+
+        renameFile(tmp, link);
+
+        break;
+    }
+}
+
+void setWriteTime(const fs::path & p, const struct stat & st)
+{
+    struct timeval times[2];
+    times[0] = {
+        .tv_sec = st.st_atime,
+        .tv_usec = 0,
+    };
+    times[1] = {
+        .tv_sec = st.st_mtime,
+        .tv_usec = 0,
+    };
+    if (lutimes(p.c_str(), times) != 0)
+        throw SysError("changing modification time of '%s'", p);
+}
+
+void copy(const fs::directory_entry & from, const fs::path & to, CopyFileFlags flags)
+{
+    // TODO: Rewrite the `is_*` to use `symlink_status()`
+    auto statOfFrom = lstat(from.path().c_str());
+    auto fromStatus = from.symlink_status();
+
+    // Mark the directory as writable so that we can delete its children
+    if (flags.deleteAfter && fs::is_directory(fromStatus)) {
+        fs::permissions(from.path(), fs::perms::owner_write, fs::perm_options::add | fs::perm_options::nofollow);
+    }
+
+
+    if (fs::is_symlink(fromStatus) || fs::is_regular_file(fromStatus)) {
+        auto opts = fs::copy_options::overwrite_existing;
+
+        if (!flags.followSymlinks) {
+            opts |= fs::copy_options::copy_symlinks;
+        }
+
+        fs::copy(from.path(), to, opts);
+    } else if (fs::is_directory(fromStatus)) {
+        fs::create_directory(to);
+        for (auto & entry : fs::directory_iterator(from.path())) {
+            copy(entry, to / entry.path().filename(), flags);
+        }
+    } else {
+        throw Error("file '%s' has an unsupported type", from.path());
+    }
+
+    setWriteTime(to, statOfFrom);
+    if (flags.deleteAfter) {
+        if (!fs::is_symlink(fromStatus))
+            fs::permissions(from.path(), fs::perms::owner_write, fs::perm_options::add | fs::perm_options::nofollow);
+        fs::remove(from.path());
+    }
+}
+
+
+void copyFile(const Path & oldPath, const Path & newPath, CopyFileFlags flags)
+{
+    return copy(fs::directory_entry(fs::path(oldPath)), fs::path(newPath), flags);
+}
+
+void renameFile(const Path & oldName, const Path & newName)
+{
+    fs::rename(oldName, newName);
+}
+
+void moveFile(const Path & oldName, const Path & newName)
+{
+    try {
+        renameFile(oldName, newName);
+    } catch (fs::filesystem_error & e) {
+        auto oldPath = fs::path(oldName);
+        auto newPath = fs::path(newName);
+        // For the move to be as atomic as possible, copy to a temporary
+        // directory
+        fs::path temp = createTempDir(newPath.parent_path(), "rename-tmp");
+        Finally removeTemp = [&]() { fs::remove(temp); };
+        auto tempCopyTarget = temp / "copy-target";
+        if (e.code().value() == EXDEV) {
+            fs::remove(newPath);
+            warn("Can’t rename %s as %s, copying instead", oldName, newName);
+            copy(fs::directory_entry(oldPath), tempCopyTarget, { .deleteAfter = true });
+            renameFile(tempCopyTarget, newPath);
+        }
+    }
+}
+
+}
--- a/Show more
+++ b/Show more