iidxhook9: add fs hook for F drive

src/main/iidxhook9/Module.mk

@@ -29,4 +29,5 @@ libs_iidxhook9      := \
 
 src_iidxhook9       := \
     config-io.c \
+    fs-hook.c \
     dllmain.c \

src/main/iidxhook9/dllmain.c

@@ -26,6 +26,7 @@
 #include "bio2emu-iidx/bi2a.h"
 
 #include "iidxhook9/config-io.h"
+#include "iidxhook9/fs-hook.h"
 
 #include "camhook/cam.h"
 #include "camhook/config-cam.h"
@@ -159,6 +160,9 @@ static bool my_dll_entry_init(char *sidcode, struct property_node *param)
         } else {
             memfile_hook_add_fd("d:\\\\001rom.txt", ABSOLUTE_MATCH, "LDJ", 3);
         }
+
+        // redirect F:\ drive to vfs (used for video recording)
+        iidxhook9_fs_hooks_init();
     }
 
     rs232_hook_init();

src/main/iidxhook9/fs-hook.c

@@ -0,0 +1,50 @@
+#define LOG_MODULE "fs-hook"
+
+#include <stdint.h>
+#include <string.h>
+
+#include "hook/table.h"
+
+#include "imports/avs.h"
+
+#include "iidxhook9/fs-hook.h"
+
+#include "util/log.h"
+#include "util/str.h"
+
+static void *(*real_avs_fs_mount)(const char *dest, const char *src, const char *fs_type, const char *options);
+static void *my_avs_fs_mount(const char *dest, const char *src, const char *fs_type, const char *options);
+
+static const struct hook_symbol avs_fs_hook_syms[] = {
+    {.name = "XCgsqzn000004b", // avs_fs_mount
+     .ordinal = 76,
+     .patch = my_avs_fs_mount,
+     .link = (void **) &real_avs_fs_mount},
+};
+
+static void *my_avs_fs_mount(const char *dest, const char *src, const char *fs_type, const char *options)
+{
+    // quick check for "F:\"
+    if (src[0] == 'F' && src[1] == ':' && src[2] == '\0') {
+        const char* dev_folder_drive = "dev/vfs/drive_f/";
+        log_misc("Redirecting %s to %s", src, dev_folder_drive);
+
+        CreateDirectoryA("dev/vfs/", NULL);
+        CreateDirectoryA("dev/vfs/drive_f/", NULL);
+
+        return real_avs_fs_mount(dest, dev_folder_drive, fs_type, options);
+    }
+
+    return real_avs_fs_mount(dest, src, fs_type, options);
+}
+
+void iidxhook9_fs_hooks_init()
+{
+    hook_table_apply(
+        NULL,
+        "avs2-core.dll",
+        avs_fs_hook_syms,
+        lengthof(avs_fs_hook_syms));
+
+    log_info("Inserted avs fs hooks");
+}

src/main/iidxhook9/fs-hook.h

@@ -0,0 +1,6 @@
+#ifndef IIDXHOOK9_FS_HOOKS_H
+#define IIDXHOOK9_FS_HOOKS_H
+
+void iidxhook9_fs_hooks_init();
+
+#endif