DynamicLoader.cpp

#include "prx/libkernel/include/Api.hpp"
#include "prx/libc/include/General.hpp"
#include "prx/libc/include/GuestAllocations.hpp"
#include "prx/libkernel/Module/ModuleArgs.hpp"
#include <nid/NidCompute.hpp>
#include <algorithm>
#include <condition_variable>
#include <filesystem>
#include <cstdio>
#include <map>
#include <memory>
#include <limits>
#include <mutex>
#include <set>
#include <string>
#include <stdexcept>
#include <system_error>
#include <vector>
#ifdef _WIN32
#ifndef NOMINMAX
#define NOMINMAX
#endif
#include <windows.h>
#else
#include <dlfcn.h>
#include <link.h>
#ifdef __linux__
#include <unistd.h>
#endif
#endif
#include "prx/libc/include/HostThreadLocal.hpp"

#ifdef _WIN32
extern "C" void ForgetUnloadedUnwindImages_nid_no_patch();
#endif

namespace {
struct LoaderErrorTag;
std::string& LoaderError() {
    return HostThreadLocal<std::string, LoaderErrorTag>();
}
thread_local bool pendingError = false;
void Error(const char* message) {
    LoaderError() = message;
    pendingError = true;
}
void LoadFailure(const std::filesystem::path& source, const std::filesystem::path& resolved, const std::string& reason) {
    std::error_code status;
    const auto message = resolved == source && std::filesystem::is_regular_file(source, status)
        ? "dlopen: " + source.string() + " was not relinked: no " + source.filename().string() + ".guest.prx was found (" + reason +
            "); relink its directory with the relinker's --module-dir <dir> option"
        : "dlopen: cannot load " + resolved.string() + " (" + reason + ")";
    Error(message.c_str());
    static std::mutex reportedLock;
    static std::set<std::filesystem::path> reported;
    std::lock_guard lock(reportedLock);
    if (reported.insert(resolved).second) std::fprintf(stderr, "[module] %s\n", message.c_str());
}
#ifdef _WIN32
HMODULE LoadWithoutErrorDialog(const std::filesystem::path& path) {
    const auto mode = GetThreadErrorMode();
    SetThreadErrorMode(mode | SEM_FAILCRITICALERRORS, nullptr);
    const auto loaded = LoadLibraryExW(path.c_str(), nullptr, LOAD_WITH_ALTERED_SEARCH_PATH);
    const auto error = GetLastError();
    SetThreadErrorMode(mode, nullptr);
    SetLastError(error);
    return loaded;
}
#endif
struct Module {
    void* native = nullptr;
    bool owned = true;
    bool global = false;
#ifdef _WIN32
    std::uintptr_t globalOrder = 0;
#endif
    ~Module() {
        if (owned && native) {
#ifdef _WIN32
            FreeLibrary(static_cast<HMODULE>(native));
            ForgetUnloadedUnwindImages_nid_no_patch();
#else
            ::dlclose(native);
#endif
        }
    }
};
std::mutex modulesMutex;
std::map<std::uintptr_t, std::shared_ptr<Module>> modules;
std::uintptr_t nextHandle = 0x20000000;
std::map<const void*, std::uintptr_t> imageIds;
void* Symbol(Module& module, const char* name) {
#ifdef _WIN32
    return reinterpret_cast<void*>(GetProcAddress(static_cast<HMODULE>(module.native), name));
#else
    return ::dlsym(module.native, name);
#endif
}
#ifndef _WIN32
const link_map* MainProgramMap() {
    static const link_map* const map = [] {
        void* handle = ::dlopen(nullptr, RTLD_LAZY);
        link_map* found = nullptr;
        const bool resolved = handle != nullptr && ::dlinfo(handle, RTLD_DI_LINKMAP, &found) == 0 && found != nullptr;
        if (handle != nullptr) ::dlclose(handle);
        if (!resolved) throw std::runtime_error("dlsym: cannot find the link map of the main program");
        return found;
    }();
    return map;
}

bool FromGuestModule(void* address) {
    Dl_info info{};
    link_map* image = nullptr;
    if (address == nullptr || !::dladdr1(address, &info, reinterpret_cast<void**>(&image), RTLD_DL_LINKMAP) || info.dli_fname == nullptr || image == nullptr) return false;
    if (image == MainProgramMap()) 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, "");
#ifdef _WIN32
    return Symbol(module, nid.c_str());
#else
    if (auto* symbol = Symbol(module, nid.c_str())) return symbol;
    constexpr char guestSuffix[] = "#guest";
    if (auto* symbol = Symbol(module, (std::string(name) + guestSuffix).c_str())) return symbol;
    return Symbol(module, (nid + guestSuffix).c_str());
#endif
}
}

extern "C" {
char* APS5_VABI dlerror_nid_postfix() {
    if (!pendingError) return nullptr;
    pendingError = false;
    return LoaderError().data();
}
#ifdef __linux__
static void InitializeLinuxGuestModule(void* native) {
    auto* table = static_cast<std::uint64_t*>(::dlsym(native, "__aps5_guest_lifecycle_nid_no_patch"));
    if (!table) return;
    link_map* requested = nullptr;
    link_map* owner = nullptr;
    Dl_info info{};
    if (::dlinfo(native, RTLD_DI_LINKMAP, &requested) != 0 || requested == nullptr ||
        !::dladdr1(table, &info, reinterpret_cast<void**>(&owner), RTLD_DL_LINKMAP) || owner == nullptr)
        throw std::runtime_error("dlopen: cannot identify guest lifecycle metadata owner");
    if (owner != requested) return;
    if (table[0] != 0x415053354c494658ull) throw std::runtime_error("dlopen: unsupported guest lifecycle metadata");
    using Entry = int (APS5_VABI *)(std::size_t, const void*, void*);
    using Initializer = void (APS5_VABI *)(int, char**, char**);
    static std::mutex initializedLock;
    static std::condition_variable initializedChanged;
    const auto thread = static_cast<std::uint64_t>(::gettid());
    std::unique_lock lock(initializedLock);
    while (table[6] == 1) {
        if (table[7] == thread) return;
        initializedChanged.wait(lock);
    }
    if (table[6] == 2) return;
    if (table[6] != 0) throw std::runtime_error("dlopen: deferred guest initialization failed or finalized");
    table[6] = 1;
    table[7] = thread;
    lock.unlock();
    try {
        const auto pending = *static_cast<const PendingModuleArgs*>(__aps5_get_pending_module_args_nid_no_patch());
        const int result = table[2] == 0 ? 0 : reinterpret_cast<Entry>(table[2])(pending.args, pending.argp, nullptr);
        for (std::uint64_t index = 0; index < table[4]; ++index) {
            const auto initializer = *reinterpret_cast<Initializer*>(table[8 + index]);
            if (initializer) initializer(0, nullptr, nullptr);
        }
        __aps5_set_module_init_result_nid_no_patch(result);
        lock.lock();
        table[6] = 2;
        table[7] = 0;
        lock.unlock();
        initializedChanged.notify_all();
    } catch (...) {
        lock.lock();
        table[6] = 3;
        table[7] = 0;
        lock.unlock();
        initializedChanged.notify_all();
        throw;
    }
}
#endif
#ifdef _WIN32
static void InitializeDeferredModule(HMODULE native) {
    using Entry = int (APS5_VABI *)(std::size_t, const void*, void*);
    using Initializer = void (APS5_VABI *)(int, char**, char**);
    constexpr auto initializing = std::numeric_limits<std::uint32_t>::max();
    static std::mutex initializedLock;
    static std::condition_variable initializedChanged;
    auto* table = reinterpret_cast<std::uint32_t*>(GetProcAddress(native, "__aps5_guest_initialize"));
    if (!table) return;
    const auto owner = GetCurrentThreadId();
    std::unique_lock lock(initializedLock);
    while (table[1] == initializing) {
        if (table[0] == 0) throw std::runtime_error("dlopen: deferred module initialization failed");
        if (table[0] == owner) return;
        initializedChanged.wait(lock);
    }
    const auto entry = table[0];
    const auto count = table[1];
    if (entry == 0 && count == 0) return;
    DWORD protection = 0;
    if (!VirtualProtect(table, 2 * sizeof(*table), PAGE_READWRITE, &protection))
        throw std::system_error(static_cast<int>(GetLastError()), std::system_category(), "open deferred module initialization metadata");
    table[0] = owner;
    table[1] = initializing;
    lock.unlock();
    const auto finish = [&](bool succeeded) {
        lock.lock();
        table[0] = 0;
        table[1] = succeeded ? 0 : initializing;
        DWORD previous = 0;
        const bool restored = VirtualProtect(table, 2 * sizeof(*table), protection, &previous);
        const auto error = restored ? ERROR_SUCCESS : GetLastError();
        if (!restored) table[1] = initializing;
        lock.unlock();
        initializedChanged.notify_all();
        if (!restored) throw std::system_error(static_cast<int>(error), std::system_category(), "restore deferred module initialization metadata");
    };
    try {
        auto* base = reinterpret_cast<std::uint8_t*>(native);
        const auto* pending = static_cast<const PendingModuleArgs*>(__aps5_get_pending_module_args_nid_no_patch());
        if (entry != 0) __aps5_set_module_init_result_nid_no_patch(reinterpret_cast<Entry>(base + entry)(pending->args, pending->argp, nullptr));
        for (std::uint32_t index = 0; index < count; ++index) {
            const auto initializer = *reinterpret_cast<Initializer*>(base + table[2 + index]);
            if (initializer) initializer(0, nullptr, nullptr);
        }
    } catch (...) {
        finish(false);
        throw;
    }
    finish(true);
}
#endif

void* APS5_VABI dlopen_nid_postfix(const char* path, int flags) {
    if ((flags & ~0x103) || (flags & 3) == 0 || (flags & 3) == 3) {
        Error("dlopen: unsupported flags"); return nullptr;
    }
    try {
        auto module = std::make_shared<Module>();
        module->global = (flags & 0x100) != 0 || !path;
#ifdef _WIN32
        if (!path) {
            module->native = GetModuleHandleW(nullptr);
            module->owned = false;
        } else {
            if (!*path) { Error("dlopen: empty module path"); return nullptr; }
            const auto source = ResolvePath_nid_no_patch(path);
            const auto resolved = RelinkedModulePath_nid_no_patch(source);
            module->native = LoadWithoutErrorDialog(resolved);
            if (!module->native) {
                const auto error = GetLastError();
                LoadFailure(source, resolved, "Windows loader error " + std::to_string(error));
                return nullptr;
            }
            InitializeDeferredModule(static_cast<HMODULE>(module->native));
        }
        if (!module->native) {
            char message[128];
            std::snprintf(message, sizeof(message), "dlopen: Windows loader error %lu (module must be host-compatible)", GetLastError());
            Error(message); return nullptr;
        }
#else
        const auto source = path ? ResolvePath_nid_no_patch(path) : std::filesystem::path{};
        const auto resolved = path ? RelinkedModulePath_nid_no_patch(source) : std::filesystem::path{};
        const int nativeFlags = ((flags & 3) == 1 ? RTLD_LAZY : RTLD_NOW) |
            ((flags & 0x100) ? RTLD_GLOBAL : RTLD_LOCAL);
        module->native = ::dlopen(path ? resolved.c_str() : nullptr, nativeFlags);
        if (!module->native) {
            if (path) LoadFailure(source, resolved, ::dlerror()); else Error(::dlerror());
            return nullptr;
        }
#ifdef __linux__
        if (path) InitializeLinuxGuestModule(module->native);
#endif
#endif
        std::lock_guard lock(modulesMutex);
        const auto handle = nextHandle++;
#ifdef _WIN32
        module->globalOrder = module->global ? handle : 0;
        for (const auto& [key, entry] : modules) {
            if (entry->native == module->native && entry->globalOrder != 0 &&
                (module->globalOrder == 0 || entry->globalOrder < module->globalOrder)) module->globalOrder = entry->globalOrder;
        }
#endif
        modules.emplace(handle, module);
#ifdef _WIN32
        for (const auto& [key, entry] : modules) {
            if (entry->native != module->native) continue;
            entry->global = module->globalOrder != 0;
            entry->globalOrder = module->globalOrder;
        }
#endif
        return reinterpret_cast<void*>(handle);
    } catch (const std::exception& error) { Error(error.what()); return nullptr; }
}
void* APS5_VABI dlsym_nid_postfix(void* handle, const char* name) {
    if (!name || !*name) { Error("dlsym: empty symbol name"); return nullptr; }
    try {
        std::vector<std::shared_ptr<Module>> search;
        {
            std::lock_guard lock(modulesMutex);
            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);
#ifdef _WIN32
                std::sort(search.begin(), search.end(), [](const auto& left, const auto& right) { return left->globalOrder < right->globalOrder; });
                search.erase(std::unique(search.begin(), search.end(), [](const auto& left, const auto& right) { return left->native == right->native; }), search.end());
#endif
            } else {
                auto found = modules.find(reinterpret_cast<std::uintptr_t>(handle));
                if (found == modules.end()) { Error("dlsym: invalid or unsupported module handle"); return nullptr; }
                search.push_back(found->second);
            }
        }
        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;
            if (auto* result = DefaultScopeSymbol((std::string(name) + "#guest").c_str())) return result;
            if (auto* result = DefaultScopeSymbol((nid + "#guest").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; }
}
int APS5_VABI dlclose_nid_postfix(void* handle) {
    const auto key = reinterpret_cast<std::uintptr_t>(handle);
    std::shared_ptr<Module> module;
    bool lastReference = true;
    {
        std::lock_guard lock(modulesMutex);
        auto found = modules.find(key);
        if (found == modules.end()) { Error("dlclose: invalid module handle"); return -1; }
        module = found->second;
        for (const auto& [other, entry] : modules) {
            if (other != key && entry->native == module->native) lastReference = false;
        }
    }
    if (module->owned && module->native && lastReference) {
        GuestAllocations::Mutation mutation;
#ifdef _WIN32
        mutation.UnregisterImage(module->native);
#else
        mutation.UnregisterImage(reinterpret_cast<const void*>(static_cast<link_map*>(module->native)->l_addr));
#endif
    }
    {
        std::lock_guard lock(modulesMutex);
        auto found = modules.find(key);
        if (found == modules.end()) { Error("dlclose: invalid module handle"); return -1; }
        modules.erase(found);
    }
    // Unload outside the registry lock: module destructors may call loader APIs.
    module.reset();
    return 0;
}
std::int32_t ModuleIdForImage_nid_no_patch(const void* native) {
    std::lock_guard lock(modulesMutex);
    for (const auto& [handle, module] : modules) {
        if (module->native == native) return static_cast<std::int32_t>(handle);
    }
    const auto [found, inserted] = imageIds.emplace(native, nextHandle);
    if (inserted) ++nextHandle;
    return static_cast<std::int32_t>(found->second);
}
}