Files
AnyPS5/core/libs/tests/WindowsWriteWatch.cpp
T
Yunus Shaikh ead292e2e5 test(libc): forget a reused section handle before the compared sharing case
WindowsMappings keys its physical pages by the section handle's value. A
handle value that an earlier case closed without ForgetSection can come
back from CreateFileMappingW with that case's stored pages, and then the
first mapping is shared from the start instead of resident, so
CheckComparedWhenShared would fail its residency check. It passes today
only because the case before it forgets its section. The case now
forgets its own handle value before it maps.
2026-10-21 07:36:47 -07:00

282 lines
15 KiB
C++

#define NOMINMAX
#include "prx/libc/include/WindowsMappings.hpp"
#include <array>
#include <atomic>
#include <iostream>
#include <set>
#include <thread>
namespace {
using Mappings = GuestArena::WindowsMappings;
using Collection = Mappings::Collection;
constexpr std::size_t Small = 4096;
constexpr std::size_t Bytes = 65536;
std::atomic<unsigned> faults{0};
void Require(bool condition, const char* message) {
if (!condition) throw std::runtime_error(message);
}
LONG CALLBACK HandleWrite(EXCEPTION_POINTERS* exception) {
const auto* record = exception->ExceptionRecord;
if (record->ExceptionCode != EXCEPTION_ACCESS_VIOLATION || record->NumberParameters < 2 || record->ExceptionInformation[0] != 1) return EXCEPTION_CONTINUE_SEARCH;
if (!Mappings::Get().HandleWrite(record->ExceptionInformation[1])) return EXCEPTION_CONTINUE_SEARCH;
++faults;
return EXCEPTION_CONTINUE_EXECUTION;
}
struct Region {
HANDLE section = CreateFileMappingW(INVALID_HANDLE_VALUE, nullptr, PAGE_EXECUTE_READWRITE | SEC_RESERVE, 0, Bytes, nullptr);
unsigned char* first = static_cast<unsigned char*>(Mappings::Get().Reserve(nullptr, Bytes));
unsigned char* alias = static_cast<unsigned char*>(Mappings::Get().Reserve(nullptr, Bytes));
Region() {
Require(section && first && alias, "cannot allocate shared test memory");
Mappings::Get().Map(first, Bytes, section, 0, PAGE_READWRITE);
Mappings::Get().Map(alias, Bytes, section, 0, PAGE_READWRITE);
}
~Region() {
Mappings::Get().Reset(first, Bytes);
Mappings::Get().Reset(alias, Bytes);
VirtualFree(first, 0, MEM_RELEASE);
VirtualFree(alias, 0, MEM_RELEASE);
CloseHandle(section);
}
void Write(std::size_t page, unsigned char value) {
static_cast<volatile unsigned char*>(first)[page * Small] = value;
}
std::set<std::size_t> Collect(Collection mode, std::size_t begin = 0, std::size_t count = 16, bool clear = true, bool useAlias = false, std::size_t capacity = 32) {
auto* base = useAlias ? alias : first;
const auto address = reinterpret_cast<std::uintptr_t>(base);
auto cursor = address + begin * Small;
const auto end = cursor + count * Small;
std::set<std::size_t> result;
while (cursor < end) {
std::array<void*, 32> pages{};
auto available = capacity;
Require(Mappings::Get().Collect(cursor, end - cursor, pages.data(), &available, clear, mode), "shared collection failed");
for (std::size_t i = 0; i < available; ++i) result.insert((reinterpret_cast<std::uintptr_t>(pages[i]) - address) / Small);
if (available < capacity) break;
cursor = reinterpret_cast<std::uintptr_t>(pages[available - 1]) + Small;
}
return result;
}
DWORD Protection(std::size_t page, bool useAlias = false) {
MEMORY_BASIC_INFORMATION info{};
Require(VirtualQuery((useAlias ? alias : first) + page * Small, &info, sizeof(info)) == sizeof(info), "protection query failed");
return info.Protect;
}
};
std::set<std::size_t> Pages(std::size_t begin, std::size_t end) {
std::set<std::size_t> result;
for (auto page = begin; page < end; ++page) result.insert(page);
return result;
}
void CheckArmed() {
Region region;
Require(region.Collect(Collection::Armed).empty(), "import collected fresh memory");
const auto before = faults.load();
region.Write(0, 1);
region.Write(4, 2);
Require(faults == before, "import armed fresh memory");
Require(region.Collect(Collection::All, 0, 1) == Pages(0, 1), "first partial collect failed");
Require(region.Protection(0) == PAGE_READONLY && region.Protection(3) == PAGE_READWRITE, "partial collect did not protect only its page");
region.Write(0, 3);
region.Write(4, 4);
Require(region.Collect(Collection::Armed) == Pages(0, 1), "armed collect lost a write or consumed fresh pages");
Require(region.Protection(4) == PAGE_READWRITE, "armed collect protected another fresh view");
Require(region.Collect(Collection::All) == Pages(1, 16), "ordinary collect lost fresh pages");
Require(region.Collect(Collection::All).empty(), "cleared memory reports writes");
}
void CheckFresh() {
Region region;
Require(region.Collect(Collection::All, 0, 1) == Pages(0, 1), "cannot collect initial page");
region.Write(0, 7);
Require(region.Collect(Collection::Fresh) == Pages(1, 16), "fresh collect consumed an existing dirty page");
Require(region.Collect(Collection::Fresh).empty(), "fresh collect repeated initial writes");
Require(region.Collect(Collection::Armed) == Pages(0, 1), "fresh collect cleared an existing write");
region.Write(9, 9);
Require(region.Collect(Collection::Armed) == Pages(9, 10), "write after activation was missed");
}
void CheckAliasesAndCapacity() {
Region region;
Require(region.Collect(Collection::All, 0, 1) == Pages(0, 1), "initial collect failed");
Require(region.Protection(0, true) == PAGE_READONLY, "alias was not protected");
Require(region.Collect(Collection::Armed, 0, 16, true, true).empty(), "alias protection was mistaken for collection history");
Require(region.Collect(Collection::Fresh, 0, 16, true, true, 1) == Pages(0, 16), "small output buffers lost fresh pages");
Require(region.Collect(Collection::Fresh, 0, 16, true, true).empty(), "small output buffers did not finish fresh collection");
static_cast<volatile unsigned char*>(region.alias)[0] = 8;
Require(region.Collect(Collection::Armed) == Pages(0, 1), "alias write was missed or fresh neighbors were consumed");
Require(region.Collect(Collection::Fresh) == Pages(1, 16), "alias collection changed another view's history");
Mappings::Get().Reset(region.first, Bytes);
Mappings::Get().Map(region.first, Bytes, region.section, 0, PAGE_READWRITE);
Require(region.Collect(Collection::Armed).empty(), "remapped address kept old collection history");
Require(region.Collect(Collection::Fresh) == Pages(0, 16), "remapped memory was not fresh");
}
void CheckPinsAndHostWrites() {
Region region;
const auto address = reinterpret_cast<std::uintptr_t>(region.first);
Mappings::Get().Pin(address, 16384);
Require(region.Collect(Collection::Fresh) == Pages(0, 16), "pinned fresh collection failed");
Require(region.Protection(0) == PAGE_READWRITE, "pinned page was protected");
Require(region.Collect(Collection::Armed) == Pages(0, 4), "pinned writes were trusted as clean");
Mappings::Get().Unpin(address, 16384);
Require(region.Collect(Collection::Armed) == Pages(0, 4), "unpin was not invalidated");
Require(region.Collect(Collection::Armed).empty(), "unpin did not restore tracking");
Require(Mappings::Get().BeginHostWrite(address, 16384), "host write refused");
region.Write(0, 3);
region.Collect(Collection::Armed);
region.Write(0, 4);
Mappings::Get().EndHostWrite(address, 16384);
Require(region.Collect(Collection::Armed) == Pages(0, 4), "host write completion was missed");
Require(region.Collect(Collection::Armed).empty(), "completed host write stayed dirty");
}
void CheckFailureAndHoles() {
Region region;
const auto address = reinterpret_cast<std::uintptr_t>(region.first);
DWORD previous;
Mappings::Get().SetProtection(address + 16384, 16384, PAGE_NOACCESS);
Require(VirtualProtect(region.first + 16384, 16384, PAGE_NOACCESS, &previous), "cannot protect test page");
std::array<void*, 32> pages{};
auto count = pages.size();
Require(!Mappings::Get().Collect(address, Bytes, pages.data(), &count, true, Collection::Fresh), "fresh inaccessible page accepted");
Require(region.Protection(0) == PAGE_READWRITE, "failed collect changed an earlier page");
Mappings::Get().SetProtection(address + 16384, 16384, PAGE_READWRITE);
Require(VirtualProtect(region.first + 16384, 16384, PAGE_READWRITE, &previous), "cannot restore test page");
Mappings::Get().Reset(region.first + 16384, 16384);
Require(region.Collect(Collection::Fresh) == std::set<std::size_t>({0, 1, 2, 3, 8, 9, 10, 11, 12, 13, 14, 15}), "fresh collection did not tolerate an unmapped block neighbor");
Require(region.Collect(Collection::Fresh).empty(), "holes caused fresh pages to repeat");
}
void CheckPrivate() {
auto& mappings = Mappings::Get();
auto* memory = static_cast<unsigned char*>(mappings.Reserve(nullptr, Bytes));
Require(memory != nullptr, "private reservation failed");
mappings.Commit(memory, Bytes, PAGE_READWRITE, Bytes, true);
const auto address = reinterpret_cast<std::uintptr_t>(memory);
std::array<void*, 32> pages{};
std::size_t count = pages.size();
mappings.Collect(address, Bytes, pages.data(), &count, true);
static_cast<volatile unsigned char*>(memory)[Small] = 3;
count = pages.size();
Require(mappings.Collect(address, Bytes, pages.data(), &count, true, Collection::Fresh) && count == 0, "fresh collect touched private memory");
count = pages.size();
Require(mappings.Collect(address, Bytes, pages.data(), &count, true, Collection::Armed) && count == 1 && pages[0] == memory + Small, "private write watch changed");
mappings.Reset(memory, Bytes);
VirtualFree(memory, 0, MEM_RELEASE);
}
void CheckForgottenSectionKeepsNoPages() {
auto& mappings = Mappings::Get();
HANDLE section = CreateFileMappingW(INVALID_HANDLE_VALUE, nullptr, PAGE_EXECUTE_READWRITE | SEC_RESERVE, 0, Bytes, nullptr);
auto* first = static_cast<unsigned char*>(mappings.Reserve(nullptr, Bytes));
auto* second = static_cast<unsigned char*>(mappings.Reserve(nullptr, Bytes));
Require(section && first && second, "cannot allocate forgotten section test memory");
const auto resident = [&](unsigned char* address) {
MEMORY_BASIC_INFORMATION info{};
Require(VirtualQuery(address, &info, sizeof(info)) == sizeof(info), "resident query failed");
return info.State == MEM_COMMIT && info.Type == MEM_PRIVATE;
};
mappings.Map(first, Bytes, section, 0, PAGE_READWRITE, true, true);
mappings.Map(second, Bytes, section, 0, PAGE_READWRITE, true, true);
Require(!resident(first) && !resident(second), "a second mapping kept the first resident");
mappings.ForgetSection(section);
mappings.Reset(first, Bytes);
mappings.Reset(second, Bytes);
mappings.Map(first, Bytes, section, 0, PAGE_READWRITE, true, true);
Require(resident(first), "a forgotten section's handle value kept its pages in the section");
first[0] = 7;
mappings.ForgetSection(section);
mappings.Reset(first, Bytes);
mappings.Map(first, Bytes, section, 0, PAGE_READWRITE, true, true);
Require(resident(first) && first[0] == 0, "a forgotten section's handle value kept its unmapped bytes");
mappings.Reset(first, Bytes);
VirtualFree(first, 0, MEM_RELEASE);
VirtualFree(second, 0, MEM_RELEASE);
CloseHandle(section);
}
void CheckConcurrentWrites() {
Region region;
std::atomic<bool> start{false};
std::thread writer([&] {
while (!start.load(std::memory_order_acquire)) std::this_thread::yield();
for (std::size_t page = 0; page < 16; ++page) region.Write(page, static_cast<unsigned char>(page + 1));
});
start.store(true, std::memory_order_release);
region.Collect(Collection::Fresh);
writer.join();
for (std::size_t page = 0; page < 16; ++page) Require(region.first[page * Small] == page + 1, "activation lost a concurrent write");
region.Collect(Collection::Armed);
Require(region.Collect(Collection::Armed).empty(), "concurrent writes did not settle");
}
void CheckComparedWhenShared() {
auto& mappings = Mappings::Get();
HANDLE section = CreateFileMappingW(INVALID_HANDLE_VALUE, nullptr, PAGE_EXECUTE_READWRITE | SEC_RESERVE, 0, 2 * Bytes, nullptr);
auto* first = static_cast<unsigned char*>(mappings.Reserve(nullptr, 2 * Bytes));
auto* second = static_cast<unsigned char*>(mappings.Reserve(nullptr, 2 * Bytes));
Require(section && first && second, "cannot allocate compared sharing test memory");
mappings.ForgetSection(section);
const auto collect = [&](unsigned char* address, std::size_t bytes) {
std::array<void*, 32> pages{};
std::size_t count = pages.size();
return mappings.Collect(reinterpret_cast<std::uintptr_t>(address), bytes, pages.data(), &count, true);
};
const auto protection = [](unsigned char* address) {
MEMORY_BASIC_INFORMATION info{};
Require(VirtualQuery(address, &info, sizeof(info)) == sizeof(info), "compared sharing protection query failed");
return info;
};
mappings.Map(first, 2 * Bytes, section, 0, PAGE_READWRITE, true, true);
Require(protection(first).Type == MEM_PRIVATE, "the compared sharing test memory is not resident");
mappings.CompareWhenShared(reinterpret_cast<std::uintptr_t>(first), Bytes);
Require(collect(first, 2 * Bytes), "a resident page to be compared when shared stopped being collected");
mappings.Map(second, 2 * Bytes, section, 0, PAGE_READWRITE, true, true);
Require(protection(first).Type == MEM_MAPPED && protection(second).Type == MEM_MAPPED, "a second mapping kept the first resident");
Require(!collect(first, Bytes) && !collect(second, Bytes), "a page to be compared when shared was collected once shared");
Require(!collect(first, 2 * Bytes), "a collect over a page to be compared when shared succeeded once shared");
Require(protection(first).Protect == PAGE_READWRITE && protection(second).Protect == PAGE_READWRITE, "a page to be compared when shared was armed once shared");
const auto before = faults.load();
first[8] = 0x5a;
second[Small + 8] = 0xa5;
Require(faults.load() == before && second[8] == 0x5a && first[Small + 8] == 0xa5, "a store into a page to be compared when shared faulted once shared");
Require(collect(first + Bytes, Bytes), "a shared page that was never to be compared stopped being collected");
mappings.Reset(first, 2 * Bytes);
mappings.Reset(second, 2 * Bytes);
for (auto* reserved : {first, second}) {
VirtualFree(reserved, 2 * Bytes, MEM_RELEASE | MEM_COALESCE_PLACEHOLDERS);
VirtualFree(reserved, 0, MEM_RELEASE);
}
mappings.ForgetSection(section);
CloseHandle(section);
}
}
int main() {
auto* handler = AddVectoredExceptionHandler(1, HandleWrite);
try {
Require(handler != nullptr, "cannot install test handler");
CheckArmed();
CheckFresh();
CheckAliasesAndCapacity();
CheckPinsAndHostWrites();
CheckFailureAndHoles();
CheckPrivate();
CheckConcurrentWrites();
CheckForgottenSectionKeepsNoPages();
CheckComparedWhenShared();
std::cout << "Windows deferred write-watch tests passed\n";
} catch (const std::exception& error) {
std::cerr << error.what() << '\n';
return 1;
}
RemoveVectoredExceptionHandler(handler);
}