diff --git a/include/dwarfs/os_access.h b/include/dwarfs/os_access.h
index d33fffef..97584312 100644
--- a/include/dwarfs/os_access.h
+++ b/include/dwarfs/os_access.h
@@ -53,5 +53,6 @@ class os_access {
   virtual std::filesystem::path
   canonical(std::filesystem::path const& path) const = 0;
   virtual std::filesystem::path current_path() const = 0;
+  virtual std::optional<std::string> getenv(std::string_view name) const = 0;
 };
 } // namespace dwarfs
diff --git a/include/dwarfs/os_access_generic.h b/include/dwarfs/os_access_generic.h
index 01998aa4..9750e9bb 100644
--- a/include/dwarfs/os_access_generic.h
+++ b/include/dwarfs/os_access_generic.h
@@ -24,6 +24,7 @@
 #include <cstddef>
 #include <filesystem>
 #include <memory>
+#include <optional>
 #include <string>
 
 #include "dwarfs/os_access.h"
@@ -45,5 +46,6 @@ class os_access_generic : public os_access {
   std::filesystem::path
   canonical(std::filesystem::path const& path) const override;
   std::filesystem::path current_path() const override;
+  std::optional<std::string> getenv(std::string_view name) const override;
 };
 } // namespace dwarfs
diff --git a/src/dwarfs/os_access_generic.cpp b/src/dwarfs/os_access_generic.cpp
index 371de4b2..fd68391a 100644
--- a/src/dwarfs/os_access_generic.cpp
+++ b/src/dwarfs/os_access_generic.cpp
@@ -19,6 +19,8 @@
  * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+#include <cstdlib>
+
 #include <folly/portability/Unistd.h>
 
 #include "dwarfs/mmap.h"
@@ -84,4 +86,13 @@ fs::path os_access_generic::canonical(fs::path const& path) const {
 
 fs::path os_access_generic::current_path() const { return fs::current_path(); }
 
+std::optional<std::string>
+os_access_generic::getenv(std::string_view name) const {
+  std::string name_str(name);
+  if (auto value = std::getenv(name_str.c_str())) {
+    return value;
+  }
+  return std::nullopt;
+}
+
 } // namespace dwarfs
diff --git a/test/test_helpers.cpp b/test/test_helpers.cpp
index a4e669e3..9493b949 100644
--- a/test/test_helpers.cpp
+++ b/test/test_helpers.cpp
@@ -459,6 +459,17 @@ std::filesystem::path os_access_mock::current_path() const {
   return root_->name;
 }
 
+void os_access_mock::setenv(std::string name, std::string value) {
+  env_[std::move(name)] = std::move(value);
+}
+
+std::optional<std::string> os_access_mock::getenv(std::string_view name) const {
+  if (auto it = env_.find(std::string(name)); it != env_.end()) {
+    return it->second;
+  }
+  return std::nullopt;
+}
+
 std::optional<fs::path> find_binary(std::string_view name) {
   auto path_str = std::getenv("PATH");
   if (!path_str) {
diff --git a/test/test_helpers.h b/test/test_helpers.h
index a205f784..92e7de54 100644
--- a/test/test_helpers.h
+++ b/test/test_helpers.h
@@ -91,6 +91,8 @@ class os_access_mock : public os_access {
 
   void set_access_fail(std::filesystem::path const& path);
 
+  void setenv(std::string name, std::string value);
+
   std::unique_ptr<dir_reader>
   opendir(std::filesystem::path const& path) const override;
 
@@ -108,6 +110,8 @@ class os_access_mock : public os_access {
 
   std::filesystem::path current_path() const override;
 
+  std::optional<std::string> getenv(std::string_view name) const override;
+
  private:
   static std::vector<std::string> splitpath(std::filesystem::path const& path);
   struct mock_dirent* find(std::filesystem::path const& path) const;
@@ -118,6 +122,7 @@ class os_access_mock : public os_access {
   std::unique_ptr<mock_dirent> root_;
   size_t ino_{1000000};
   std::set<std::filesystem::path> access_fail_set_;
+  std::map<std::string, std::string> env_;
 };
 
 class script_mock : public script {