[Memory] Close shared memory FD and properly handle its invalid value

src/xenia/base/memory.h

@@ -18,6 +18,7 @@
 
 #include "xenia/base/assert.h"
 #include "xenia/base/byte_order.h"
+#include "xenia/base/platform.h"
 
 namespace xe {
 namespace memory {
@@ -96,7 +97,15 @@ void AlignedFree(T* ptr) {
 #endif  // XE_COMPILER_MSVC
 }
 
+#if XE_PLATFORM_WIN32
+// HANDLE.
 typedef void* FileMappingHandle;
+constexpr FileMappingHandle kFileMappingHandleInvalid = nullptr;
+#else
+// File descriptor.
+typedef int FileMappingHandle;
+constexpr FileMappingHandle kFileMappingHandleInvalid = -1;
+#endif
 
 FileMappingHandle CreateFileMappingHandle(const std::filesystem::path& path,
                                           size_t length, PageAccess access,

src/xenia/base/memory_posix.cc

@@ -86,19 +86,19 @@ FileMappingHandle CreateFileMappingHandle(const std::filesystem::path& path,
       assert_always();
       return nullptr;
   }
-
   oflag |= O_CREAT;
   auto full_path = "/" / path;
   int ret = shm_open(full_path.c_str(), oflag, 0777);
-  if (ret > 0) {
-    ftruncate64(ret, length);
+  if (ret < 0) {
+    return kFileMappingHandleInvalid;
   }
-
-  return ret <= 0 ? nullptr : reinterpret_cast<FileMappingHandle>(ret);
+  ftruncate64(ret, length);
+  return ret;
 }
 
 void CloseFileMappingHandle(FileMappingHandle handle,
                             const std::filesystem::path& path) {
+  close(handle);
   auto full_path = "/" / path;
   shm_unlink(full_path.c_str());
 }
@@ -106,8 +106,8 @@ void CloseFileMappingHandle(FileMappingHandle handle,
 void* MapFileView(FileMappingHandle handle, void* base_address, size_t length,
                   PageAccess access, size_t file_offset) {
   uint32_t prot = ToPosixProtectFlags(access);
-  return mmap64(base_address, length, prot, MAP_PRIVATE | MAP_ANONYMOUS,
-                reinterpret_cast<intptr_t>(handle), file_offset);
+  return mmap64(base_address, length, prot, MAP_PRIVATE | MAP_ANONYMOUS, handle,
+                file_offset);
 }
 
 bool UnmapFileView(FileMappingHandle handle, void* base_address,

src/xenia/base/testing/memory_test.cc

@@ -421,7 +421,7 @@ TEST_CASE("create_and_close_file_mapping", "Virtual Memory Mapping") {
   auto path = fmt::format("xenia_test_{}", Clock::QueryHostTickCount());
   auto memory = xe::memory::CreateFileMappingHandle(
       path, 0x100, xe::memory::PageAccess::kReadWrite, true);
-  REQUIRE(memory);
+  REQUIRE(memory != xe::memory::FileMappingHandleInvalid);
   xe::memory::CloseFileMappingHandle(memory, path);
 }
 
@@ -430,7 +430,7 @@ TEST_CASE("map_view", "Virtual Memory Mapping") {
   const size_t length = 0x100;
   auto memory = xe::memory::CreateFileMappingHandle(
       path, length, xe::memory::PageAccess::kReadWrite, true);
-  REQUIRE(memory);
+  REQUIRE(memory != xe::memory::FileMappingHandleInvalid);
 
   uintptr_t address = 0x100000000;
   auto view =
@@ -447,7 +447,7 @@ TEST_CASE("read_write_view", "Virtual Memory Mapping") {
   auto path = fmt::format("xenia_test_{}", Clock::QueryHostTickCount());
   auto memory = xe::memory::CreateFileMappingHandle(
       path, length, xe::memory::PageAccess::kReadWrite, true);
-  REQUIRE(memory);
+  REQUIRE(memory != xe::memory::FileMappingHandleInvalid);
 
   uintptr_t address = 0x100000000;
   auto view =