Merge pull request #864 from jeffrey12cali/fix/dlsym-default-scope

fix(module): resolve the default dlsym scope against the main program

core/libs/prx/libkernel/CMakeLists.txt

@@ -104,6 +104,9 @@ if(BUILD_TESTING)
     target_link_libraries(guest_dynamic_loader_tests PRIVATE libkernel libc)
     configure_windows_unwind(guest_dynamic_loader_tests)
     add_dependencies(guest_dynamic_loader_tests guest_module_fixture)
+    if(NOT WIN32)
+        set_target_properties(guest_dynamic_loader_tests PROPERTIES ENABLE_EXPORTS ON)
+    endif()
     add_test(NAME guest_dynamic_loader COMMAND guest_dynamic_loader_tests $<TARGET_FILE_NAME:guest_module_fixture>)
     set_tests_properties(guest_dynamic_loader PROPERTIES
         WORKING_DIRECTORY "$<TARGET_FILE_DIR:guest_module_fixture>")

core/libs/prx/libkernel/Module/src/DynamicLoader.cpp

@@ -15,6 +15,7 @@
 #include <windows.h>
 #else
 #include <dlfcn.h>
+#include <link.h>
 #endif
 
 namespace {
@@ -49,6 +50,39 @@ void* Symbol(Module& module, const char* name) {
     return ::dlsym(module.native, name);
 #endif
 }
+#ifndef _WIN32
+std::uintptr_t MainProgramBase() {
+    static const std::uintptr_t base = [] {
+        struct Scan {
+            std::uintptr_t value = 0;
+        };
+        Scan scan;
+        ::dl_iterate_phdr(
+            [](dl_phdr_info* info, size_t, void* data) {
+                auto* found = static_cast<Scan*>(data);
+                if (found->value == 0 && info->dlpi_name != nullptr && info->dlpi_name[0] == '\0') found->value = info->dlpi_addr;
+                return found->value == 0 ? 0 : 1;
+            },
+            &scan);
+        return scan.value;
+    }();
+    return base;
+}
+
+bool FromGuestModule(void* address) {
+    Dl_info info{};
+    if (address == nullptr || !::dladdr(address, &info) || info.dli_fname == nullptr) return false;
+    if (reinterpret_cast<std::uintptr_t>(info.dli_fbase) == MainProgramBase()) return true;
+    const std::string path(info.dli_fname);
+    return path.ends_with(".prx");
+}
+
+void* DefaultScopeSymbol(const char* symbolName) {
+    auto* result = ::dlsym(RTLD_DEFAULT, symbolName);
+    return FromGuestModule(result) ? result : nullptr;
+}
+#endif
+
 void* FindSymbol(Module& module, const char* name) {
     if (auto* symbol = Symbol(module, name)) return symbol;
     const auto nid = Nid::ComputeNid(name, "");
@@ -116,7 +150,7 @@ void* APS5_VABI dlsym_nid_postfix(void* handle, const char* name) {
         std::vector<std::shared_ptr<Module>> search;
         {
             std::lock_guard lock(modulesMutex);
-            if (handle == reinterpret_cast<void*>(static_cast<std::intptr_t>(-2))) {
+            if (handle == nullptr || handle == reinterpret_cast<void*>(static_cast<std::intptr_t>(-2))) {
                 for (const auto& [key, module] : modules) if (module->global) search.push_back(module);
             } else {
                 auto found = modules.find(reinterpret_cast<std::uintptr_t>(handle));
@@ -125,6 +159,13 @@ void* APS5_VABI dlsym_nid_postfix(void* handle, const char* name) {
             }
         }
         for (const auto& module : search) if (auto* result = FindSymbol(*module, name)) return result;
+#ifndef _WIN32
+        if (handle == nullptr || handle == reinterpret_cast<void*>(static_cast<std::intptr_t>(-2))) {
+            if (auto* result = DefaultScopeSymbol(name)) return result;
+            const auto nid = Nid::ComputeNid(name, "");
+            if (auto* result = DefaultScopeSymbol(nid.c_str())) return result;
+        }
+#endif
         Error("dlsym: symbol not found in supported module scope");
         return nullptr;
     } catch (const std::exception& error) { Error(error.what()); return nullptr; }

core/libs/tests/GuestDynamicLoader.cpp

@@ -2,6 +2,9 @@
 #include <cstdlib>
 #include <filesystem>
 #include <fstream>
+#ifndef _WIN32
+#include <dlfcn.h>
+#endif
 #include <stdexcept>
 #include <thread>
 extern "C" {
@@ -13,6 +16,9 @@ int APS5_VABI _sceKernelRtldThreadAtexitIncrement_nid_postfix(const void*);
 int APS5_VABI _sceKernelRtldThreadAtexitDecrement_nid_postfix(const void*);
 }
 static void Require(bool value) { if (!value) std::abort(); }
+#ifndef _WIN32
+extern "C" int APS5_VABI GuestDefaultScopeOnly(int a, int b) { return a * b; }
+#endif
 template<typename TFunction>
 static bool ThrowsRuntimeError(TFunction function) {
     try {
@@ -38,6 +44,7 @@ int main(int argc, char** argv) {
     auto add = reinterpret_cast<Add>(dlsym_nid_postfix(module, "GuestModuleAdd"));
     Require(add && add(17, 25) == 42);
     Require(dlsym_nid_postfix(reinterpret_cast<void*>(-2), "GuestModuleAdd") == reinterpret_cast<void*>(add));
+    Require(dlsym_nid_postfix(nullptr, "GuestModuleAdd") == reinterpret_cast<void*>(add));
 #ifndef _WIN32
     auto mul = reinterpret_cast<Add>(dlsym_nid_postfix(module, "GuestModuleMul"));
     Require(mul && mul(6, 7) == 42);
@@ -88,4 +95,20 @@ int main(int argc, char** argv) {
     Require(ThrowsRuntimeError([] { _sceKernelRtldThreadAtexitDecrement_nid_postfix(reinterpret_cast<const void*>(&Require)); }));
     int local = 0;
     Require(ThrowsRuntimeError([&] { _sceKernelRtldThreadAtexitIncrement_nid_postfix(&local); }));
+#ifndef _WIN32
+    Require(dlsym_nid_postfix(nullptr, "malloc") == nullptr);
+    Require(dlsym_nid_postfix(nullptr, "dlopen") == nullptr);
+    Require(dlsym_nid_postfix(nullptr, "pthread_create") == nullptr);
+    Require(dlsym_nid_postfix(nullptr, "GuestDefaultScopeOnly") == reinterpret_cast<void*>(&GuestDefaultScopeOnly));
+    Require(dlsym_nid_postfix(reinterpret_cast<void*>(-2), "GuestDefaultScopeOnly") == reinterpret_cast<void*>(&GuestDefaultScopeOnly));
+    const auto hostLoaded = std::filesystem::absolute("anyps5-host-loaded-module-for-test.prx");
+    std::filesystem::copy_file(argv[1], hostLoaded, std::filesystem::copy_options::overwrite_existing);
+    void* host = ::dlopen(hostLoaded.c_str(), RTLD_NOW | RTLD_GLOBAL);
+    Require(host != nullptr);
+    void* hostAdd = ::dlsym(host, "3qcG+yBRS+s");
+    Require(hostAdd != nullptr);
+    Require(dlsym_nid_postfix(nullptr, "GuestModuleAdd") == hostAdd);
+    Require(dlsym_nid_postfix(nullptr, "malloc") == nullptr);
+    Require(::dlclose(host) == 0);
+#endif
 }