9 files changed, 101 insertions, 66 deletions
diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index 520f50c30..bcff653c5 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -2,6 +2,8 @@
 #include "args/root.hh"
 #include "hash.hh"
 #include "json-utils.hh"
+#include "environment-variables.hh"
+
 #include "experimental-features-json.hh"
 
 #include <glob.h>
diff --git a/src/libutil/environment-variables.cc b/src/libutil/environment-variables.cc
new file mode 100644
index 000000000..71c404a0e
--- /dev/null
+++ b/src/libutil/environment-variables.cc
@@ -0,0 +1,51 @@
+#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);
+}
+
+}
diff --git a/src/libutil/environment-variables.hh b/src/libutil/environment-variables.hh
new file mode 100644
index 000000000..784b95921
--- /dev/null
+++ b/src/libutil/environment-variables.hh
@@ -0,0 +1,42 @@
+#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);
+
+}
diff --git a/src/libutil/error.cc b/src/libutil/error.cc
index b534ff87e..fe73ffc56 100644
--- a/src/libutil/error.cc
+++ b/src/libutil/error.cc
@@ -1,3 +1,4 @@
+#include "environment-variables.hh"
 #include "error.hh"
 #include "position.hh"
 
diff --git a/src/libutil/filesystem.cc b/src/libutil/filesystem.cc
index b637281d0..85871870c 100644
--- a/src/libutil/filesystem.cc
+++ b/src/libutil/filesystem.cc
@@ -2,6 +2,7 @@
 #include <filesystem>
 #include <atomic>
 
+#include "environment-variables.hh"
 #include "finally.hh"
 #include "util.hh"
 #include "signals.hh"
diff --git a/src/libutil/logging.cc b/src/libutil/logging.cc
index 0e63f9bd6..8e4828be4 100644
--- a/src/libutil/logging.cc
+++ b/src/libutil/logging.cc
@@ -1,3 +1,4 @@
+#include "environment-variables.hh"
 #include "logging.hh"
 #include "util.hh"
 #include "config.hh"
diff --git a/src/libutil/meson.build b/src/libutil/meson.build
index 58e0bd062..01b3e24b7 100644
--- a/src/libutil/meson.build
+++ b/src/libutil/meson.build
@@ -7,6 +7,7 @@ libutil_sources = files(
   'compute-levels.cc',
   'config.cc',
   'english.cc',
+  'environment-variables.cc',
   'error.cc',
   'escape-char.cc',
   'escape-string.cc',
@@ -53,6 +54,7 @@ libutil_headers = files(
   'config-impl.hh',
   'config.hh',
   'english.hh',
+  'environment-variables.hh',
   'error.hh',
   'escape-char.hh',
   'escape-string.hh',
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 2c0fcc897..97d53ca63 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -4,6 +4,7 @@
 #include "serialise.hh"
 #include "cgroup.hh"
 #include "signals.hh"
+#include "environment-variables.hh"
 
 #include <array>
 #include <cctype>
@@ -43,57 +44,12 @@
 #endif
 
 
-extern char * * environ __attribute__((weak));
-
-
 #ifdef NDEBUG
 #error "Lix may not be built with assertions disabled (i.e. with -DNDEBUG)."
 #endif
 
 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);
-}
-
-
 Path absPath(Path path, std::optional<PathView> dir, bool resolveSymlinks)
 {
     if (path.empty() || path[0] != '/') {
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 14868776c..151da25b9 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -40,27 +40,6 @@ extern const std::string nativeSystem;
 
 
 /**
- * @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();
-
-/**
  * @return An absolutized path, resolving paths relative to the
  * specified directory, or the current directory otherwise.  The path
  * is also canonicalised.