Add libretro assets directory search path, and have environment variables override configured values (#17054)

* platform_win32: Fix sizeof for DEFAULT_DIR_PLAYLIST.

* frontend/drivers/platform_win32.c (frontend_win32_env_get): Check
the size of correct destination array.

* frontend: Honor the LIBRETRO_ASSETS_DIRECTORY environment variable.

This builds on 763fcd8267 ("unix, win32: Allow set the default
libretro_directory via environment variable") to also allow specifying
the assets directory via an environment variable.

* frontend/drivers/platform_unix.c (frontend_unix_get_env)
<libretro_assets_directory> New variable. Use it to set
DEFAULT_DIR_ASSETS, when available.
* frontend/drivers/platform_win32.c (frontend_win32_env_get): Likewise.

* platform: Honor the LIBRETRO_DIRECTORY environment variable.

Until now, and unlike the defaut core directory, the default
core *info* directory would be hard-coded relative to the installation
directory. Honor the LIBRETRO_DIRECTORY environment variable the same
instead.

* frontend/drivers/platform_unix.c (frontend_unix_get_env): Set
DEFAULT_DIR_CORE_INFO default to the value of the LIBRETRO_DIRECTORY
environment variable, if available.
* frontend/drivers/platform_win32.c (frontend_win32_env_get): Likewise.

* platform: Honor the LIBRETRO_AUTOCONFIG_DIRECTORY environment variable.

* frontend/drivers/platform_unix.c
(libretro_autoconfig_directory): New variable.
(frontend_unix_get_env): Set DEFAULT_DIR_AUTOCONFIG to the value of
the LIBRETRO_AUTOCONFIG_DIRECTORY environment variable, if available.
* frontend/drivers/platform_win32.c: Likewise.

* platform: Honor the LIBRETRO_VIDEO_FILTER_DIRECTORY environment variable.

* frontend/drivers/platform_unix.c
(libretro_video_filter_directory): New variable.
(frontend_unix_get_env): Set DEFAULT_DIR_VIDEO_FILTER to the value of
the LIBRETRO_VIDEO_FILTER_DIRECTORY environment variable, if available.
* frontend/drivers/platform_win32.c: Likewise.

* platform: Honor the LIBRETRO_VIDEO_SHADER_DIRECTORY environment variable.

* frontend/drivers/platform_unix.c
(libretro_video_shader_directory): New variable.
(frontend_unix_get_env): Set DEFAULT_DIR_SHADER to the value of
the LIBRETRO_VIDEO_SHADER_DIRECTORY environment variable, if available.
* frontend/drivers/platform_win32.c: Likewise.

* platform: Honor the LIBRETRO_SYSTEM_DIRECTORY environment variable.

* frontend/drivers/platform_unix.c
(libretro_system_directory): New variable.
(frontend_unix_get_env): Set DEFAULT_DIR_SYSTEM to the value of
the LIBRETRO_SYSTEM_DIRECTORY environment variable, if available.
* frontend/drivers/platform_win32.c: Likewise.

* configuration: Have environment variables override configuration.

Because the configuration file is systematically written when
RetroArch terminates, persisting any previous default/configured
value, setting the LIBRETRO_DIRECTORY, LIBRETRO_ASSETS_DIRECTORY, etc.
environment variables would not have an effect unless the
retroarch.cfg configuration file was cleared.

This seems to go against the common expectation that environment
variables are set by users to *override* the default behavior or
configuration of an application.

* configuration.c (config_load_file) <libretro_directory>
<libretro_assets_directory, libretro_autoconfig_directory>
<libretro_system_directory, libretro_video_filter_directory>
<libretro_video_shader_directory>: New variables. Use the values of
the LIBRETRO_DIRECTORY, LIBRETRO_ASSETS_DIRECTORY,
LIBRETRO_AUTOCONFIG_DIRECTORY, LIBRETRO_SYSTEM_DIRECTORY,
LIBRETRO_VIDEO_FILTER_DIRECTORY and LIBRETRO_VIDEO_SHADER_DIRECTORY
environment variables instead of their corresponding configured
values, when set.
* docs/retroarch.6: Document the environment variables honored and
their behavior.

configuration.c

@@ -3568,6 +3568,12 @@ static bool config_load_file(global_t *global,
 {
    unsigned i;
    char tmp_str[PATH_MAX_LENGTH];
+   char* libretro_directory                        = NULL;
+   char* libretro_assets_directory                 = NULL;
+   char* libretro_autoconfig_directory             = NULL;
+   char* libretro_system_directory                 = NULL;
+   char* libretro_video_filter_directory           = NULL;
+   char* libretro_video_shader_directory           = NULL;
    static bool first_load                          = true;
    bool without_overrides                          = false;
    unsigned msg_color                              = 0;
@@ -3849,12 +3855,6 @@ static bool config_load_file(global_t *global,
          strlcpy(path_settings[i].ptr, tmp_str, PATH_MAX_LENGTH);
    }
 
-#if !IOS
-   if (config_get_path(conf, "libretro_directory", tmp_str, sizeof(tmp_str)))
-      configuration_set_string(settings,
-            settings->paths.directory_libretro, tmp_str);
-#endif
-
 #ifdef RARCH_CONSOLE
    if (conf)
       video_driver_load_settings(global, conf);
@@ -3862,6 +3862,26 @@ static bool config_load_file(global_t *global,
 
    /* Post-settings load */
 
+   libretro_directory = getenv("LIBRETRO_DIRECTORY");
+   if (libretro_directory) {
+      configuration_set_string(settings,
+            settings->paths.directory_libretro, libretro_directory);
+      configuration_set_string(settings,
+            settings->paths.path_libretro_info, libretro_directory);
+   }
+
+   libretro_autoconfig_directory = getenv("LIBRETRO_AUTOCONFIG_DIRECTORY");
+   if (libretro_autoconfig_directory)
+       configuration_set_string(settings,
+				settings->paths.directory_autoconfig,
+				libretro_autoconfig_directory);
+
+   libretro_system_directory = getenv("LIBRETRO_SYSTEM_DIRECTORY");
+   if (libretro_system_directory)
+       configuration_set_string(settings,
+				settings->paths.directory_system,
+				libretro_system_directory);
+
    if (     (rarch_flags & RARCH_FLAGS_HAS_SET_USERNAME)
          && (override_username))
    {
@@ -4026,15 +4046,27 @@ static bool config_load_file(global_t *global,
       *settings->paths.path_menu_wallpaper = '\0';
    if (string_is_equal(settings->paths.path_rgui_theme_preset, "default"))
       *settings->paths.path_rgui_theme_preset = '\0';
-   if (string_is_equal(settings->paths.directory_video_shader, "default"))
+   libretro_video_shader_directory = getenv("LIBRETRO_VIDEO_SHADER_DIRECTORY");
+   if (libretro_video_shader_directory) { /* override configuration value */
+      configuration_set_string(settings, settings->paths.directory_video_shader,
+			       libretro_video_shader_directory);
+   } else if (string_is_equal(settings->paths.directory_video_shader, "default"))
       *settings->paths.directory_video_shader = '\0';
-   if (string_is_equal(settings->paths.directory_video_filter, "default"))
+   libretro_video_filter_directory = getenv("LIBRETRO_VIDEO_FILTER_DIRECTORY");
+   if (libretro_video_filter_directory) { /* override configuration value */
+       configuration_set_string(settings, settings->paths.directory_video_filter,
+				libretro_video_filter_directory);
+   } else if (string_is_equal(settings->paths.directory_video_filter, "default"))
       *settings->paths.directory_video_filter = '\0';
    if (string_is_equal(settings->paths.directory_audio_filter, "default"))
       *settings->paths.directory_audio_filter = '\0';
    if (string_is_equal(settings->paths.directory_core_assets, "default"))
       *settings->paths.directory_core_assets = '\0';
-   if (string_is_equal(settings->paths.directory_assets, "default"))
+   libretro_assets_directory = getenv("LIBRETRO_ASSETS_DIRECTORY");
+   if (libretro_assets_directory) { /* override configuration value */
+      configuration_set_string(settings,
+           settings->paths.directory_assets, libretro_assets_directory);
+   } else if (string_is_equal(settings->paths.directory_assets, "default"))
       *settings->paths.directory_assets = '\0';
 #ifdef _3DS
    if (string_is_equal(settings->paths.directory_bottom_assets, "default"))

docs/retroarch.6

@@ -1,6 +1,6 @@
 .\" retroarch.6:
 
-.TH  "RETROARCH" "6" "November 1, 2011" "RETROARCH" "System Manager's Manual: retroarch"
+.TH  "RETROARCH" "6" "January 16, 2025" "RETROARCH" "System Manager's Manual: retroarch"
 
 .SH NAME
 
@@ -239,3 +239,42 @@ Disables all kinds of content patching.
 .TP
 \fB-D, --detach\fR
 Detach from the current console. This is currently only relevant for Microsoft Windows.
+
+.SH ENVIRONMENT
+\fBretroarch\fR honors the following environment variables:
+
+.TP
+\fBLIBRETRO_DIRECTORY\fR
+Specify the directory where RetroArch looks for core and info files,
+overriding the value of the "libretro_directory" configuration file
+option.
+
+.TP
+\fBLIBRETRO_ASSETS_DIRECTORY\fR
+Specify the directory where RetroArch looks for assets, overriding
+the value of the "assets_directory" configuration file
+option.
+
+.TP
+\fBLIBRETRO_AUTOCONFIG_DIRECTORY\fR
+Specify the directory where RetroArch looks for controller
+auto-configuration files, overriding the value of the
+"joypad_autoconfig_dir" configuration file option.
+
+.TP
+\fBLIBRETRO_SYSTEM_DIRECTORY\fR
+Specify the directory where RetroArch looks for system files,
+overriding the value of the "system_directory" configuration file
+option.
+
+.TP
+\fBLIBRETRO_VIDEO_FILTER_DIRECTORY\fR
+Specify the directory where RetroArch looks for video filters,
+overriding the value of the "video_filter_dir" configuration file
+option.
+
+.TP
+\fBLIBRETRO_VIDEO_SHADER_DIRECTORY\fR
+Specify the directory where RetroArch looks for video shaders,
+overriding the value of the "video_shader_dir" configuration file
+option.

frontend/drivers/platform_unix.c

@@ -1323,6 +1323,11 @@ static void frontend_unix_get_env(int *argc,
 {
    unsigned i;
    const char* libretro_directory = getenv("LIBRETRO_DIRECTORY");
+   const char* libretro_assets_directory = getenv("LIBRETRO_ASSETS_DIRECTORY");
+   const char* libretro_autoconfig_directory = getenv("LIBRETRO_AUTOCONFIG_DIRECTORY");
+   const char* libretro_system_directory = getenv("LIBRETRO_SYSTEM_DIRECTORY");
+   const char* libretro_video_filter_directory = getenv("LIBRETRO_VIDEO_FILTER_DIRECTORY");
+   const char* libretro_video_shader_directory = getenv("LIBRETRO_VIDEO_SHADER_DIRECTORY");
 #ifdef ANDROID
    int32_t major, minor, rel;
    char device_model[PROP_VALUE_MAX]  = {0};
@@ -1764,12 +1769,20 @@ static void frontend_unix_get_env(int *argc,
             "cores", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
    else
 #endif
+   if (!string_is_empty(libretro_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_CORE_INFO], libretro_directory,
+            sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
+   else
       fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_CORE_INFO], base_path,
             "cores", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
 #endif
+   if (!string_is_empty(libretro_autoconfig_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG],
+	    libretro_autoconfig_directory,
+            sizeof(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG]));
+   else
        fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG], base_path,
             "autoconfig", sizeof(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG]));
-
 #ifdef ASSETS_DIR
    if (path_is_directory(ASSETS_DIR "/assets"))
       fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_ASSETS],
@@ -1777,7 +1790,10 @@ static void frontend_unix_get_env(int *argc,
             "assets", sizeof(g_defaults.dirs[DEFAULT_DIR_ASSETS]));
    else
 #endif
-   if (path_is_directory("/usr/local/share/retroarch/assets"))
+   if (!string_is_empty(libretro_assets_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_ASSETS], libretro_assets_directory,
+	      sizeof(g_defaults.dirs[DEFAULT_DIR_ASSETS]));
+   else if (path_is_directory("/usr/local/share/retroarch/assets"))
       fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_ASSETS],
             "/usr/local/share/retroarch",
             "assets", sizeof(g_defaults.dirs[DEFAULT_DIR_ASSETS]));
@@ -1837,7 +1853,11 @@ static void frontend_unix_get_env(int *argc,
             "filters/video", sizeof(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER]));
    else
 #endif
-   if (path_is_directory("/usr/local/share/retroarch/filters/video"))
+   if (!string_is_empty(libretro_video_filter_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER],
+	      libretro_video_filter_directory,
+	      sizeof(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER]));
+   else if (path_is_directory("/usr/local/share/retroarch/filters/video"))
       fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER],
             "/usr/local/share/retroarch",
             "filters/video", sizeof(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER]));
@@ -1871,6 +1891,11 @@ static void frontend_unix_get_env(int *argc,
          "records", sizeof(g_defaults.dirs[DEFAULT_DIR_RECORD_OUTPUT]));
    fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_DATABASE], base_path,
          "database/rdb", sizeof(g_defaults.dirs[DEFAULT_DIR_DATABASE]));
+   if (!string_is_empty(libretro_video_shader_directory))
+       strlcpy(g_defaults.dirs[DEFAULT_DIR_SHADER],
+	       libretro_video_shader_directory,
+	       sizeof(g_defaults.dirs[DEFAULT_DIR_SHADER]));
+   else
        fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_SHADER], base_path,
              "shaders", sizeof(g_defaults.dirs[DEFAULT_DIR_SHADER]));
    fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_CHEATS], base_path,
@@ -1891,6 +1916,11 @@ static void frontend_unix_get_env(int *argc,
          "saves", sizeof(g_defaults.dirs[DEFAULT_DIR_SRAM]));
    fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_SAVESTATE], base_path,
          "states", sizeof(g_defaults.dirs[DEFAULT_DIR_SAVESTATE]));
+   if (!string_is_empty(libretro_system_directory))
+       strlcpy(g_defaults.dirs[DEFAULT_DIR_SYSTEM],
+	       libretro_system_directory,
+	       sizeof(g_defaults.dirs[DEFAULT_DIR_SYSTEM]));
+   else
        fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_SYSTEM], base_path,
              "system", sizeof(g_defaults.dirs[DEFAULT_DIR_SYSTEM]));
 #endif

frontend/drivers/platform_win32.c

@@ -566,16 +566,31 @@ static void frontend_win32_env_get(int *argc, char *argv[],
 {
    const char *tmp_dir = getenv("TMP");
    const char *libretro_directory = getenv("LIBRETRO_DIRECTORY");
+   const char *libretro_assets_directory = getenv("LIBRETRO_ASSETS_DIRECTORY");
+   const char* libretro_autoconfig_directory = getenv("LIBRETRO_AUTOCONFIG_DIRECTORY");
+   const char* libretro_system_directory = getenv("LIBRETRO_SYSTEM_DIRECTORY");
+   const char* libretro_video_filter_directory = getenv("LIBRETRO_VIDEO_FILTER_DIRECTORY");
+   const char* libretro_video_shader_directory = getenv("LIBRETRO_VIDEO_SHADER_DIRECTORY");
    if (!string_is_empty(tmp_dir))
       fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_CACHE],
          tmp_dir, sizeof(g_defaults.dirs[DEFAULT_DIR_CACHE]));
 
    gfx_set_dwm();
 
-   fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_ASSETS],
+   if (!string_is_empty(libretro_assets_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_ASSETS], libretro_assets_directory,
+	      sizeof(g_defaults.dirs[DEFAULT_DIR_ASSETS]));
+   else
+       fill_pathname_expand_special(
+	   g_defaults.dirs[DEFAULT_DIR_ASSETS],
 	   ":\\assets", sizeof(g_defaults.dirs[DEFAULT_DIR_ASSETS]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_AUDIO_FILTER],
       ":\\filters\\audio", sizeof(g_defaults.dirs[DEFAULT_DIR_AUDIO_FILTER]));
+   if (!string_is_empty(libretro_video_filter_directory))
+       strlcpy(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER],
+	       libretro_video_filter_directory,
+	       sizeof(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER]));
+   else
        fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER],
            ":\\filters\\video", sizeof(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_CHEATS],
@@ -583,7 +598,7 @@ static void frontend_win32_env_get(int *argc, char *argv[],
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_DATABASE],
       ":\\database\\rdb", sizeof(g_defaults.dirs[DEFAULT_DIR_DATABASE]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_PLAYLIST],
-      ":\\playlists", sizeof(g_defaults.dirs[DEFAULT_DIR_ASSETS]));
+      ":\\playlists", sizeof(g_defaults.dirs[DEFAULT_DIR_PLAYLIST]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_RECORD_CONFIG],
       ":\\config\\record", sizeof(g_defaults.dirs[DEFAULT_DIR_RECORD_CONFIG]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_RECORD_OUTPUT],
@@ -606,10 +621,24 @@ static void frontend_win32_env_get(int *argc, char *argv[],
    else
       fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_CORE],
             ":\\cores", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE]));
+   if (!string_is_empty(libretro_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_CORE_INFO], libretro_directory,
+            sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
+   else
        fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_CORE_INFO],
            ":\\info", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
+   if (!string_is_empty(libretro_autoconfig_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG],
+	      libretro_autoconfig_directory,
+	      sizeof(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG]));
+   else
        fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG],
              ":\\autoconfig", sizeof(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG]));
+   if (!string_is_empty(libretro_video_filter_directory))
+      strlcpy(g_defaults.dirs[DEFAULT_DIR_SHADER],
+	      libretro_video_shader_directory,
+	      sizeof(g_defaults.dirs[DEFAULT_DIR_SHADER]));
+   else
        fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_SHADER],
              ":\\shaders", sizeof(g_defaults.dirs[DEFAULT_DIR_SHADER]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_CORE_ASSETS],
@@ -620,6 +649,11 @@ static void frontend_win32_env_get(int *argc, char *argv[],
       ":\\saves", sizeof(g_defaults.dirs[DEFAULT_DIR_SRAM]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_SAVESTATE],
       ":\\states", sizeof(g_defaults.dirs[DEFAULT_DIR_SAVESTATE]));
+   if (!string_is_empty(libretro_system_directory))
+       strlcpy(g_defaults.dirs[DEFAULT_DIR_SYSTEM],
+	       libretro_system_directory,
+	       sizeof(g_defaults.dirs[DEFAULT_DIR_SYSTEM]));
+   else
        fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_SYSTEM],
              ":\\system", sizeof(g_defaults.dirs[DEFAULT_DIR_SYSTEM]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_LOGS],