Allows discovery of assets file via the LIBRETRO_ASSETS_DIRECTORY environment
variable.

Upstream-status: https://github.com/libretro/RetroArch/pull/17054

diff --git a/configuration.c b/configuration.c
index 5808a3f21c..0cc2909102 100644
--- a/configuration.c
+++ b/configuration.c
@@ -3573,6 +3573,11 @@ 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_video_filter_directory           = NULL;
+   char* libretro_video_shader_directory           = NULL;
    static bool first_load                          = true;
    bool without_overrides                          = false;
    unsigned msg_color                              = 0;
@@ -3848,12 +3853,6 @@ 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);
@@ -3861,6 +3860,20 @@ 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);
+
    if (     (rarch_flags & RARCH_FLAGS_HAS_SET_USERNAME)
          && (override_username))
    {
@@ -4032,15 +4045,27 @@ 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"))
diff --git a/docs/retroarch.6 b/docs/retroarch.6
index 7478040e17..f864e0e0d5 100644
--- a/docs/retroarch.6
+++ b/docs/retroarch.6
@@ -1,6 +1,6 @@
 .\" retroarch.6:
 
-.TH  "RETROARCH" "6" "November 1, 2011" "RETROARCH" "System Manager's Manual: retroarch"
+.TH  "RETROARCH" "6" "September 28, 2024" "RETROARCH" "System Manager's Manual: retroarch"
 
 .SH NAME
 
@@ -239,3 +239,36 @@ 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_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.
diff --git a/frontend/drivers/platform_unix.c b/frontend/drivers/platform_unix.c
index c157d355a1..ddf0b5ca87 100644
--- a/frontend/drivers/platform_unix.c
+++ b/frontend/drivers/platform_unix.c
@@ -1324,6 +1324,10 @@ 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_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};
@@ -1765,12 +1769,20 @@ static void frontend_unix_get_env(int *argc,
             "cores", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
    else
 #endif
-   fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_CORE_INFO], base_path,
-         "cores", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
+   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
-   fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG], base_path,
-         "autoconfig", sizeof(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG]));
-
+   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],
@@ -1778,7 +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]));
@@ -1838,7 +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]));
@@ -1872,8 +1891,13 @@ 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]));
-   fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_SHADER], base_path,
-         "shaders", sizeof(g_defaults.dirs[DEFAULT_DIR_SHADER]));
+   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,
          "cheats", sizeof(g_defaults.dirs[DEFAULT_DIR_CHEATS]));
    fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_OVERLAY], base_path,
diff --git a/frontend/drivers/platform_win32.c b/frontend/drivers/platform_win32.c
index 26ed25c04f..0cc9a9dc95 100644
--- a/frontend/drivers/platform_win32.c
+++ b/frontend/drivers/platform_win32.c
@@ -565,24 +565,38 @@ 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_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],
-      ":\\assets", sizeof(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]));
-   fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_VIDEO_FILTER],
-      ":\\filters\\video", sizeof(g_defaults.dirs[DEFAULT_DIR_VIDEO_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],
       ":\\cheats", sizeof(g_defaults.dirs[DEFAULT_DIR_CHEATS]));
    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],
@@ -605,12 +619,26 @@ 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]));
-   fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_CORE_INFO],
-      ":\\info", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_INFO]));
-   fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG],
-      ":\\autoconfig", sizeof(g_defaults.dirs[DEFAULT_DIR_AUTOCONFIG]));
-   fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_SHADER],
-      ":\\shaders", sizeof(g_defaults.dirs[DEFAULT_DIR_SHADER]));
+   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],
       ":\\downloads", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_ASSETS]));
    fill_pathname_expand_special(g_defaults.dirs[DEFAULT_DIR_SCREENSHOT],