From c2b8be4c4f2e986490dcd2bf86d810c4e030be7e Mon Sep 17 00:00:00 2001
From: Craig Carnell <1188869+cscd98@users.noreply.github.com>
Date: Mon, 3 Aug 2026 10:40:11 +0100
Subject: [PATCH] libretro: add vfs aware file checks in retro_load_game

---
 Makefile.common         |  1 +
 libretro/libretro.c     | 21 ++++++++++++---------
 libretro/libretro_vfs.c | 39 +++++++++++++++++++++++++++++++++++++++
 libretro/libretro_vfs.h | 14 ++++++++++++++
 4 files changed, 66 insertions(+), 9 deletions(-)
 create mode 100644 libretro/libretro_vfs.c
 create mode 100644 libretro/libretro_vfs.h

diff --git a/Makefile.common b/Makefile.common
index 72aef3abc..575dbb5aa 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -232,6 +232,7 @@ endif
 
 # Libretro
 SOURCES_C += $(LIBRETRO_DIR)/libretro.c \
+	$(LIBRETRO_DIR)/libretro_vfs.c \
 	$(LIBRETRO_COMM_DIR)/memmap/memalign.c \
 	$(ROOT_DIR)/custom/mupen64plus-core/plugin/emulate_game_controller_via_libretro.c \
 	$(LIBRETRO_COMM_DIR)/audio/resampler/drivers/sinc_resampler.c \
diff --git a/libretro/libretro.c b/libretro/libretro.c
index 76656668b..98d49377b 100644
--- a/libretro/libretro.c
+++ b/libretro/libretro.c
@@ -56,6 +56,7 @@
 #include "device/rcp/pi/pi_controller.h"
 #include "device/pif/pif.h"
 #include "libretro_memory.h"
+#include "libretro_vfs.h"
 
 #include "audio_plugin.h"
 
@@ -646,6 +647,13 @@ void retro_set_environment(retro_environment_t cb)
     environ_cb(RETRO_ENVIRONMENT_SET_SUBSYSTEM_INFO, (void*)subsystems);
     environ_cb(RETRO_ENVIRONMENT_GET_CLEAR_ALL_THREAD_WAITS_CB, &environ_clear_thread_waits_cb);
     
+    struct retro_vfs_interface_info vfs_iface_info;
+    vfs_iface_info.required_interface_version = 3;
+    vfs_iface_info.iface = NULL;
+
+    if (environ_cb(RETRO_ENVIRONMENT_GET_VFS_INTERFACE, &vfs_iface_info))
+        vfs_interface = vfs_iface_info.iface;
+
     setup_variables();
 }
 
@@ -1891,12 +1899,11 @@ bool retro_load_game(const struct retro_game_info *game)
         newPath = (char*)calloc(1, strlen(gamePath)+5);
         strcpy(newPath, gamePath);
         strcat(newPath, ".ndd");
-        FILE* fileTest = fopen(newPath, "r");
-        if(!fileTest)
+
+        if (!vfs_file_exists(newPath))
         {
             free(newPath);
         } else {
-            fclose(fileTest);
             // Free'd later in Mupen Core
             retro_dd_path_img = newPath;
         }
@@ -1908,14 +1915,12 @@ bool retro_load_game(const struct retro_game_info *game)
        newPath = (char *)calloc(1, strlen(gamePath) + 4);
        strcpy(newPath, gamePath);
        strcat(newPath, ".gb");
-       FILE *fileTest = fopen(newPath, "r");
-       if (!fileTest)
+       if (!vfs_file_exists(newPath))
        {
           free(newPath);
        }
        else
        {
-          fclose(fileTest);
           // Free'd later in Mupen Core
           retro_transferpak_rom_path = newPath;
  
@@ -1926,14 +1931,12 @@ bool retro_load_game(const struct retro_game_info *game)
              newPath = (char *)calloc(1, strlen(gamePath) + 5);
              strcpy(newPath, gamePath);
              strcat(newPath, ".sav");
-             FILE *fileTest = fopen(newPath, "r");
-             if (!fileTest)
+             if (!vfs_file_exists(newPath))
              {
                 free(newPath);
              }
              else
              {
-                fclose(fileTest);
                 // Free'd later in Mupen Core
                 retro_transferpak_ram_path = newPath;
              }
diff --git a/libretro/libretro_vfs.c b/libretro/libretro_vfs.c
new file mode 100644
index 000000000..7a1816ada
--- /dev/null
+++ b/libretro/libretro_vfs.c
@@ -0,0 +1,39 @@
+#include "libretro_vfs.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct retro_vfs_interface *vfs_interface = NULL;
+
+void *vfs_fopen(const char *path, bool write)
+{
+    if (vfs_interface)
+    {
+        unsigned access = write ? RETRO_VFS_FILE_ACCESS_WRITE
+                                 : RETRO_VFS_FILE_ACCESS_READ;
+        return (void*)vfs_interface->open(path, access, RETRO_VFS_FILE_ACCESS_HINT_NONE);
+    }
+
+    return (void*)fopen(path, write ? "wb" : "rb");
+}
+
+bool vfs_file_exists(const char *path)
+{
+    void *fp = vfs_fopen(path, false);
+    if (!fp)
+        return false;
+
+    vfs_fclose(fp);
+    return true;
+}
+
+void vfs_fclose(void *fp)
+{
+    if (!fp)
+        return;
+
+    if (vfs_interface)
+        vfs_interface->close((struct retro_vfs_file_handle*)fp);
+    else
+        fclose((FILE*)fp);
+}
diff --git a/libretro/libretro_vfs.h b/libretro/libretro_vfs.h
new file mode 100644
index 000000000..0d1fb6052
--- /dev/null
+++ b/libretro/libretro_vfs.h
@@ -0,0 +1,14 @@
+#ifndef _LIBRETRO_VFS_H_
+#define _LIBRETRO_VFS_H_
+
+#include <stdbool.h>
+
+#include "libretro.h"
+
+extern struct retro_vfs_interface *vfs_interface;
+
+void *vfs_fopen(const char *path, bool write);
+bool vfs_file_exists(const char *path);
+void vfs_fclose(void *fp);
+
+#endif