diff --git a/selfdrive/common/params.cc b/selfdrive/common/params.cc
index 6a2a89038e..e7006aba7e 100644
--- a/selfdrive/common/params.cc
+++ b/selfdrive/common/params.cc
@@ -327,12 +327,12 @@ std::string Params::get(const char *key, bool block) {
   }
 }
 
-int Params::readAll(std::map<std::string, std::string> *params) {
+std::map<std::string, std::string> Params::readAll() {
   FileLock file_lock(params_path + "/.lock", LOCK_SH);
   std::lock_guard<FileLock> lk(file_lock);
 
   std::string key_path = params_path + "/d";
-  return util::read_files_in_dir(key_path, params);
+  return util::read_files_in_dir(key_path);
 }
 
 void Params::clearAll(ParamKeyType key_type) {
diff --git a/selfdrive/common/params.h b/selfdrive/common/params.h
index bc13722955..52aab815f7 100644
--- a/selfdrive/common/params.h
+++ b/selfdrive/common/params.h
@@ -33,7 +33,7 @@ public:
   void clearAll(ParamKeyType type);
 
   // read all values
-  int readAll(std::map<std::string, std::string> *params);
+  std::map<std::string, std::string> readAll();
 
   // helpers for reading values
   std::string get(const char *key, bool block = false);
diff --git a/selfdrive/common/util.cc b/selfdrive/common/util.cc
index 78f9e409f9..e6fabc2b95 100644
--- a/selfdrive/common/util.cc
+++ b/selfdrive/common/util.cc
@@ -76,19 +76,20 @@ std::string read_file(const std::string& fn) {
   return std::string();
 }
 
-int read_files_in_dir(const std::string &path, std::map<std::string, std::string> *contents) {
+std::map<std::string, std::string> read_files_in_dir(const std::string &path) {
+  std::map<std::string, std::string> ret;
   DIR *d = opendir(path.c_str());
-  if (!d) return -1;
+  if (!d) return ret;
 
   struct dirent *de = NULL;
   while ((de = readdir(d))) {
     if (isalnum(de->d_name[0])) {
-      (*contents)[de->d_name] = util::read_file(path + "/" + de->d_name);
+      ret[de->d_name] = util::read_file(path + "/" + de->d_name);
     }
   }
 
   closedir(d);
-  return 0;
+  return ret;
 }
 
 int write_file(const char* path, const void* data, size_t size, int flags, mode_t mode) {
diff --git a/selfdrive/common/util.h b/selfdrive/common/util.h
index 460fb8f5c0..1637a8380a 100644
--- a/selfdrive/common/util.h
+++ b/selfdrive/common/util.h
@@ -62,7 +62,7 @@ bool is_valid_dongle_id(std::string const& dongle_id);
 
 // **** file fhelpers *****
 std::string read_file(const std::string& fn);
-int read_files_in_dir(const std::string& path, std::map<std::string, std::string>* contents);
+std::map<std::string, std::string> read_files_in_dir(const std::string& path);
 int write_file(const char* path, const void* data, size_t size, int flags = O_WRONLY, mode_t mode = 0777);
 std::string readlink(const std::string& path);
 bool file_exists(const std::string& fn);
diff --git a/selfdrive/loggerd/bootlog.cc b/selfdrive/loggerd/bootlog.cc
index 86c4473af5..35508730fd 100644
--- a/selfdrive/loggerd/bootlog.cc
+++ b/selfdrive/loggerd/bootlog.cc
@@ -12,8 +12,7 @@ static kj::Array<capnp::word> build_boot_log() {
   boot.setWallTimeNanos(nanos_since_epoch());
 
   std::string pstore = "/sys/fs/pstore";
-  std::map<std::string, std::string> pstore_map;
-  util::read_files_in_dir(pstore, &pstore_map);
+  std::map<std::string, std::string> pstore_map = util::read_files_in_dir(pstore);
 
   const std::vector<std::string> log_keywords = {"Kernel panic"};
   auto lpstore = boot.initPstore().initEntries(pstore_map.size());
diff --git a/selfdrive/loggerd/logger.cc b/selfdrive/loggerd/logger.cc
index 6436b960b8..8651530b47 100644
--- a/selfdrive/loggerd/logger.cc
+++ b/selfdrive/loggerd/logger.cc
@@ -101,8 +101,7 @@ kj::Array<capnp::word> logger_build_init_data() {
   init.setPassive(params.getBool("Passive"));
   init.setDongleId(params.get("DongleId"));
   {
-    std::map<std::string, std::string> params_map;
-    params.readAll(&params_map);
+    std::map<std::string, std::string> params_map = params.readAll();
     auto lparams = init.initParams().initEntries(params_map.size());
     int i = 0;
     for (auto& kv : params_map) {