Create a default config file if it doesn't exist.

file.h

@@ -74,6 +74,8 @@ bool path_is_directory(const char *path);
 bool path_file_exists(const char *path);
 const char *path_get_extension(const char *path);
 
+bool path_mkdir(const char *dir);
+
 // Removes all text after and including the last '.'
 char *path_remove_extension(char *path);
 

file_path.c

@@ -19,6 +19,7 @@
 #include "boolean.h"
 #include <string.h>
 #include <time.h>
+#include <errno.h>
 #include "compat/strl.h"
 #include "compat/posix_string.h"
 
@@ -44,6 +45,7 @@
 #else
 #include <io.h>
 #include <fcntl.h>
+#include <direct.h>
 #include <windows.h>
 #endif
 #else
@@ -564,6 +566,64 @@ void path_resolve_realpath(char *buf, size_t size)
 #endif
 }
 
+static bool path_mkdir_norecurse(const char *dir)
+{
+#if (defined(_WIN32) && !defined(_XBOX)) || !defined(RARCH_CONSOLE)
+#ifdef _WIN32
+   int ret = _mkdir(dir);
+#else
+   int ret = mkdir(dir, 0750);
+#endif
+   if (ret < 0 && errno == EEXIST && path_is_directory(dir)) // Don't treat this as an error.
+      ret = 0;
+   if (ret < 0)
+      RARCH_ERR("mkdir(%s) error: %s.\n", dir, strerror(errno));
+   return ret == 0;
+#else
+   (void)dir;
+   return false;
+#endif
+}
+
+bool path_mkdir(const char *dir)
+{
+   const char *target = NULL;
+   char *basedir = strdup(dir); // Use heap. Real chance of stack overflow if we recurse too hard.
+   bool ret = true;
+
+   if (!basedir)
+      return false;
+
+   path_parent_dir(basedir);
+   if (!*basedir || !strcmp(basedir, dir))
+   {
+      ret = false;
+      goto end;
+   }
+
+   if (path_is_directory(basedir))
+   {
+      target = dir;
+      ret = path_mkdir_norecurse(dir);
+   }
+   else
+   {
+      target = basedir;
+      ret = path_mkdir(basedir);
+      if (ret)
+      {
+         target = dir;
+         ret = path_mkdir_norecurse(dir);
+      }
+   }
+
+end:
+   if (target && !ret)
+      RARCH_ERR("Failed to create directory: \"%s\".\n", target);
+   free(basedir);
+   return ret;
+}
+
 void fill_pathname_resolve_relative(char *out_path, const char *in_refpath, const char *in_path, size_t size)
 {
    if (path_is_absolute(in_path))

frontend/frontend.c

@@ -67,6 +67,7 @@ static bool libretro_install_core(const char *path_prefix,
 
 void rarch_make_dir(const char *x, const char *name)
 {
+   // FIXME: This should use path_mkdir() in file_path.c.
    RARCH_LOG("Checking directory name %s [%s]\n", name, x);
    if (strlen(x) > 0)
    {

settings.c

@@ -392,6 +392,28 @@ static config_file_t *open_default_config_file(void)
       }
    }
 
+   // Try to create a new config file.
+   if (!conf)
+   {
+      conf = config_file_new(NULL);
+      bool saved = false;
+      if (conf) // Since this is a clean config file, we can safely use config_save_on_exit.
+      {
+         fill_pathname_resolve_relative(conf_path, app_path, "retroarch.cfg", sizeof(conf_path));
+         config_set_bool(conf, "config_save_on_exit", true);
+         saved = config_file_write(conf, conf_path);
+      }
+
+      if (saved)
+         RARCH_WARN("Created new config file in: \"%s\".\n", conf_path); // WARN here to make sure user has a good chance of seeing it.
+      else
+      {
+         RARCH_ERR("Failed to create new config file in: \"%s\".\n", conf_path);
+         config_file_free(conf);
+         conf = NULL;
+      }
+   }
+
    if (conf)
       strlcpy(g_extern.config_path, conf_path, sizeof(g_extern.config_path));
 #elif !defined(__CELLOS_LV2__) && !defined(_XBOX)
@@ -401,9 +423,9 @@ static config_file_t *open_default_config_file(void)
 
    // XDG_CONFIG_HOME falls back to $HOME/.config.
    if (xdg)
-      snprintf(conf_path, sizeof(conf_path), "%s/retroarch/retroarch.cfg", xdg);
+      fill_pathname_join(conf_path, xdg, "retroarch/retroarch.cfg", sizeof(conf_path));
    else if (home)
-      snprintf(conf_path, sizeof(conf_path), "%s/.config/retroarch/retroarch.cfg", home);
+      fill_pathname_join(conf_path, home, ".config/retroarch/retroarch.cfg", sizeof(conf_path));
 
    if (xdg || home)
    {
@@ -414,12 +436,45 @@ static config_file_t *open_default_config_file(void)
    // Fallback to $HOME/.retroarch.cfg.
    if (!conf && home)
    {
-      snprintf(conf_path, sizeof(conf_path), "%s/.retroarch.cfg", home);
+      fill_pathname_join(conf_path, home, ".retroarch.cfg", sizeof(conf_path));
       RARCH_LOG("Looking for config in: \"%s\".\n", conf_path);
       conf = config_file_new(conf_path);
    }
 
-   // Try this as a last chance ...
+   // Try to create a new config file.
+   if (!conf && (home || xdg))
+   {
+      // XDG_CONFIG_HOME falls back to $HOME/.config.
+      if (xdg)
+         fill_pathname_join(conf_path, xdg, "retroarch/retroarch.cfg", sizeof(conf_path));
+      else if (home)
+         fill_pathname_join(conf_path, home, ".config/retroarch/retroarch.cfg", sizeof(conf_path));
+
+      char basedir[PATH_MAX];
+      fill_pathname_basedir(basedir, conf_path, sizeof(basedir));
+
+      if (path_mkdir(basedir))
+      {
+         conf = config_file_new(NULL);
+         bool saved = false;
+         if (conf)
+         {
+            config_set_bool(conf, "config_save_on_exit", true); // Since this is a clean config file, we can safely use config_save_on_exit.
+            saved = config_file_write(conf, conf_path);
+         }
+
+         if (saved)
+            RARCH_WARN("Created new config file in: \"%s\".\n", conf_path); // WARN here to make sure user has a good chance of seeing it.
+         else
+         {
+            RARCH_ERR("Failed to create new config file in: \"%s\".\n", conf_path);
+            config_file_free(conf);
+            conf = NULL;
+         }
+      }
+   }
+
+   // Try this as a very last chance ...
    if (!conf)
    {
 #ifndef GLOBAL_CONFIG_DIR