path-lookup: introduce user_search_dirs() (shall replace xdg_user_dirs())

xdg_user_dirs() doesn't seem well-organized currently.
In all other xdg_user_*() funcs we assume /etc/xdg/systemd
to be a symlink to /etc/systemd/, hence it is the odd one out.
Also, when the relevant envvar is unset, it only returns
the global search dirs.

sd_path_lookup() actually covers this nicely with SD_PATH_SEARCH_*,
where the combined search paths (from user home and system) are used.
Therefore, let's introduce a wrapper for that, and deprecate xdg_user_dirs()
(would be removed in later commits).

src/libsystemd/sd-path/path-lookup.c

@@ -17,6 +17,27 @@
 #include "tmpfile-util.h"
 #include "user-util.h"
 
+int user_search_dirs(const char *suffix, char ***ret_config_dirs, char ***ret_data_dirs) {
+        _cleanup_strv_free_ char **config_dirs = NULL, **data_dirs = NULL;
+        int r;
+
+        assert(ret_config_dirs);
+        assert(ret_data_dirs);
+
+        r = sd_path_lookup_strv(SD_PATH_SEARCH_CONFIGURATION, suffix, &config_dirs);
+        if (r < 0)
+                return r;
+
+        r = sd_path_lookup_strv(SD_PATH_SEARCH_SHARED, suffix, &data_dirs);
+        if (r < 0)
+                return r;
+
+        *ret_config_dirs = TAKE_PTR(config_dirs);
+        *ret_data_dirs = TAKE_PTR(data_dirs);
+
+        return 0;
+}
+
 int runtime_directory(RuntimeScope scope, const char *suffix, char **ret) {
         int r;
 

src/libsystemd/sd-path/path-lookup.h

@@ -65,6 +65,7 @@ int xdg_user_dirs(char ***ret_config_dirs, char ***ret_data_dirs);
 /* We don't treat /etc/xdg/systemd/ in these functions as the xdg base dir spec suggests because we assume
  * that is a link to /etc/systemd/ anyway. */
 
+int user_search_dirs(const char *suffix, char ***ret_config_dirs, char ***ret_data_dirs);
 static inline int xdg_user_runtime_dir(const char *suffix, char **ret) {
         return sd_path_lookup(SD_PATH_USER_RUNTIME, suffix, ret);
 }

src/tmpfiles/tmpfiles.c

@@ -349,49 +349,35 @@ static int log_unresolvable_specifier(const char *filename, unsigned line) {
                  arg_dry_run ? (would) : (doing),       \
                  __VA_ARGS__)
 
-static int user_config_paths(char*** ret) {
+static int user_config_paths(char ***ret) {
         _cleanup_strv_free_ char **config_dirs = NULL, **data_dirs = NULL;
-        _cleanup_free_ char *persistent_config = NULL, *runtime_config = NULL, *data_home = NULL;
-        _cleanup_strv_free_ char **res = NULL;
+        _cleanup_free_ char *runtime_config = NULL;
         int r;
 
-        r = xdg_user_dirs(&config_dirs, &data_dirs);
-        if (r < 0)
-                return r;
+        assert(ret);
 
-        r = xdg_user_config_dir("/user-tmpfiles.d", &persistent_config);
-        if (r < 0 && !ERRNO_IS_NEG_NOINFO(r))
+        /* Combined user-specific and global dirs */
+        r = user_search_dirs("/user-tmpfiles.d", &config_dirs, &data_dirs);
+        if (r < 0)
                 return r;
 
         r = xdg_user_runtime_dir("/user-tmpfiles.d", &runtime_config);
         if (r < 0 && !ERRNO_IS_NEG_NOINFO(r))
                 return r;
 
-        r = xdg_user_data_dir("/user-tmpfiles.d", &data_home);
-        if (r < 0 && !ERRNO_IS_NEG_NOINFO(r))
-                return r;
-
-        r = strv_extend_strv_concat(&res, (const char* const*) config_dirs, "/user-tmpfiles.d");
+        r = strv_consume(&config_dirs, TAKE_PTR(runtime_config));
         if (r < 0)
                 return r;
 
-        r = strv_extend_many(
-                        &res,
-                        persistent_config,
-                        runtime_config,
-                        data_home);
+        r = strv_extend_strv_consume(&config_dirs, TAKE_PTR(data_dirs), /* filter_duplicates = */ true);
         if (r < 0)
                 return r;
 
-        r = strv_extend_strv_concat(&res, (const char* const*) data_dirs, "/user-tmpfiles.d");
+        r = path_strv_make_absolute_cwd(config_dirs);
         if (r < 0)
                 return r;
 
-        r = path_strv_make_absolute_cwd(res);
-        if (r < 0)
-                return r;
-
-        *ret = TAKE_PTR(res);
+        *ret = TAKE_PTR(config_dirs);
         return 0;
 }