Add a log message when loading libretro save state made with incompatible mkxp-z version

binding-sandbox/binding-sandbox.cpp

@@ -20,7 +20,8 @@
 */
 
 #include "binding-sandbox.h"
-#include <cstring>
+#include "mkxp-polyfill.h" // std::strtol
+#include <string>
 #include <libretro.h>
 #include <zlib.h>
 #include "sharedstate.h"
@@ -535,6 +536,26 @@ void sandbox_binding_init::operator()() {
     static VALUE system_module;
     static VALUE cfg_module;
 
+    struct register_ruby_revision : boost::asio::coroutine {
+        typedef decl_slots<wasm_ptr_t, VALUE, ID> slots;
+
+        void operator()() {
+            BOOST_ASIO_CORO_REENTER (this) {
+                SANDBOX_AWAIT_S(2, rb_intern, "RUBY_REVISION");
+                SANDBOX_AWAIT_S(1, rb_const_get, sb()->rb_cObject(), SANDBOX_SLOT(2));
+                SANDBOX_AWAIT_S(0, rb_string_value_cstr, &SANDBOX_SLOT(1));
+
+                struct sandbox_str_guard str = sb()->str(SANDBOX_SLOT(0));
+                if (std::strlen(str) != 2 * sizeof mkxp_retro::ruby_revision) {
+                    std::abort();
+                }
+                for (size_t i = 0; i < sizeof mkxp_retro::ruby_revision; ++i) {
+                    mkxp_retro::ruby_revision[i] = std::strtol(std::string(str + 2 * i, 2).c_str(), nullptr, 16);
+                }
+            }
+        }
+    };
+
     struct register_utf8_encoding : boost::asio::coroutine {
         typedef decl_slots<ID> slots;
 
@@ -547,6 +568,7 @@ void sandbox_binding_init::operator()() {
     };
 
     BOOST_ASIO_CORO_REENTER (this) {
+        SANDBOX_AWAIT(register_ruby_revision);
         SANDBOX_AWAIT(register_utf8_encoding);
         SANDBOX_AWAIT(exception_binding_init);
 

binding-sandbox/hasher.cpp

@@ -0,0 +1,70 @@
+/*
+** hasher.cpp
+**
+** This file is part of mkxp.
+**
+** Copyright (C) 2013 - 2021 Amaryllis Kulla <ancurio@mapleshrine.eu>
+**
+** mkxp is free software: you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation, either version 2 of the License, or
+** (at your option) any later version.
+**
+** mkxp is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with mkxp.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <cstdint>
+#include <fstream>
+#include <iostream>
+#include <vector>
+#include <picosha2.h>
+
+int main(int argc, char **argv) {
+    if (argc < 2) {
+        std::cerr << "[hasher] error: at least one argument must be passed to this program" << std::endl;
+        return 1;
+    }
+
+    picosha2::hash256_one_by_one digest;
+
+    for (int i = 2; i < argc; ++i) {
+        std::ifstream file(argv[i], std::ios::binary);
+        if (!file.is_open()) {
+            std::cerr << "[hasher] error: could not open input file " << argv[i] << std::endl;
+            return 2;
+        }
+        std::vector<uint8_t> buffer;
+        for (;;) {
+            uint8_t byte = file.get();
+            if (file.eof()) {
+                break;
+            }
+            buffer.push_back(byte);
+        }
+        digest.process(buffer.begin(), buffer.end());
+    }
+
+    digest.finish();
+    std::vector<uint8_t> bytes(picosha2::k_digest_size);
+    digest.get_hash_bytes(bytes.begin(), bytes.end());
+
+    std::ofstream file(argv[1]);
+    if (!file.is_open()) {
+        std::cerr << "[hasher] error: could not open output file " << argv[1] << std::endl;
+        return 3;
+    }
+    file << "#ifndef MKXPZ_BINDING_SANDBOX_HASH" << std::endl;
+    file << "#  define MKXPZ_BINDING_SANDBOX_HASH \"" << std::hex;
+    for (uint8_t byte : bytes) {
+        file << "\\x" << (unsigned int)byte;
+    }
+    file << '"' << std::endl << "#endif" << std::endl;
+
+    return 0;
+}

binding-sandbox/meson.build

@@ -1,4 +1,4 @@
-global_sources += files(
+binding_sandbox_sources = files(
     'audio-binding.cpp',
     'binding-base.cpp',
     'binding-sandbox.cpp',
@@ -22,3 +22,32 @@ global_sources += files(
     'window-binding.cpp',
     'windowvx-binding.cpp',
 )
+
+global_sources += binding_sandbox_sources
+
+binding_sandbox_hasher = executable(
+    'binding-sandbox-hasher',
+    dependencies: subproject('picosha2').get_variable('picosha2'),
+    sources: 'hasher.cpp',
+    native: true,
+    override_options: [
+        'buildtype=release',
+        'b_coverage=false',
+        'b_lto=false',
+        'b_ndebug=false',
+        'b_pgo=off',
+        'b_sanitize=none',
+        'cpp_std=c++11',
+    ],
+)
+
+global_sources += custom_target(
+    'binding-sandbox-hash',
+    input: binding_sandbox_sources,
+    output: 'binding-sandbox-hash.h',
+    command: [
+        binding_sandbox_hasher,
+        '@OUTPUT@',
+        '@INPUT@',
+    ],
+)

src/core.cpp

@@ -40,6 +40,7 @@
 
 #include "mkxp-polyfill.h" // std::mutex, std::strtoul
 #include "git-hash.h"
+#include "binding-sandbox-hash.h"
 
 #include "al-util.h"
 #include "audio.h"
@@ -636,6 +637,8 @@ namespace mkxp_retro {
     uint8_t midi_chorus_override;
     uint8_t midi_reverb_override;
 
+    uint8_t ruby_revision[20];
+
     uint64_t get_ticks_ms() noexcept {
         return frame_time / 1000;
     }
@@ -1622,6 +1625,19 @@ extern "C" RETRO_API bool retro_serialize(void *data, size_t len) {
     // Write 4-byte version: 1
     if (!sandbox_serialize((uint32_t)1, data, max_size)) return false;
 
+    // Write mkxp-z version
+    if (!sandbox_serialize(MKXPZ_VERSION "/" MKXPZ_GIT_HASH, data, max_size)) return false;
+
+    // Write 20-byte Ruby revision
+    RESERVE(sizeof ruby_revision);
+    std::memcpy(data, ruby_revision, sizeof ruby_revision);
+    ADVANCE(sizeof ruby_revision);
+
+    // Write 32-byte hash of binding-sandbox source files
+    RESERVE(sizeof MKXPZ_BINDING_SANDBOX_HASH - 1);
+    std::memcpy(data, MKXPZ_BINDING_SANDBOX_HASH, sizeof MKXPZ_BINDING_SANDBOX_HASH - 1);
+    ADVANCE(sizeof MKXPZ_BINDING_SANDBOX_HASH - 1);
+
     // Write the capacity of the VM memory
     if (!sandbox_serialize(sb()->memory_capacity(), data, max_size)) return false;
 
@@ -1770,6 +1786,26 @@ extern "C" RETRO_API bool retro_unserialize(const void *data, size_t len) {
         if (version != 1) return false;
     }
 
+    // Read mkxp-z version that the save state was created by
+    std::string mkxpz_version;
+    if (!sandbox_deserialize(mkxpz_version, data, max_size)) return false;
+
+    // Make sure the Ruby revision matches that of that version of mkxp-z, since save state compatibility breaks when the Ruby version changes
+    RESERVE(sizeof ruby_revision);
+    if (std::memcmp(data, ruby_revision, sizeof ruby_revision)) {
+        log_printf(RETRO_LOG_ERROR, "Failed to load save state because it uses a different Ruby version than the current version of mkxp-z; try using mkxp-z version %s to load this save state instead\n", mkxpz_version.c_str());
+        return false;
+    }
+    ADVANCE(sizeof ruby_revision);
+
+    // Make sure the hash of the binding-sandbox source files matches that of that version of mkxp-z, since save state compatibility breaks when the sandbox bindings are modified
+    RESERVE(sizeof MKXPZ_BINDING_SANDBOX_HASH - 1);
+    if (std::memcmp(data, MKXPZ_BINDING_SANDBOX_HASH, sizeof MKXPZ_BINDING_SANDBOX_HASH - 1)) {
+        log_printf(RETRO_LOG_ERROR, "Failed to load save state because the sandbox bindings used are incompatible with the current version of mkxp-z; try using mkxp-z version %s to load this save state instead\n", mkxpz_version.c_str());
+        return false;
+    }
+    ADVANCE(sizeof MKXPZ_BINDING_SANDBOX_HASH - 1);
+
     // Read the VM memory
     {
         wasm_size_t memory_capacity;

src/core.h

@@ -50,6 +50,8 @@ namespace mkxp_retro {
     extern uint8_t midi_chorus_override;
     extern uint8_t midi_reverb_override;
 
+    extern uint8_t ruby_revision[20];
+
     uint64_t get_ticks_ms() noexcept;
     uint64_t get_ticks_us() noexcept;
     double get_refresh_rate() noexcept;

subprojects/packagefiles/picosha2/meson.build

@@ -0,0 +1,2 @@
+project('picosha2', 'cpp', meson_version: '>=1.3.0')
+picosha2 = declare_dependency(include_directories: '.')

subprojects/picosha2.wrap

@@ -0,0 +1,5 @@
+[wrap-git]
+url = https://github.com/okdshin/PicoSHA2
+revision = v1.0.1
+depth = 1
+patch_directory = picosha2