Merge pull request #10277 from AdmiralCurtiss/memarena-cleanup

MemArena: Cleanup & interface changes for safer memory mapping.

1 files changed, 94 insertions, 0 deletions

diff --git a/Source/Core/Common/MemArenaUnix.cpp b/Source/Core/Common/MemArenaUnix.cpp
new file mode 100644
index 0000000000..1743c2ace0
--- /dev/null
+++ b/Source/Core/Common/MemArenaUnix.cpp
@@ -0,0 +1,94 @@
+// Copyright 2008 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "Common/MemArena.h"
+
+#include <cerrno>
+#include <cstddef>
+#include <cstdlib>
+#include <cstring>
+#include <set>
+#include <string>
+
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "Common/CommonFuncs.h"
+#include "Common/CommonTypes.h"
+#include "Common/Logging/Log.h"
+#include "Common/MsgHandler.h"
+#include "Common/StringUtil.h"
+
+namespace Common
+{
+MemArena::MemArena() = default;
+MemArena::~MemArena() = default;
+
+void MemArena::GrabSHMSegment(size_t size)
+{
+  const std::string file_name = "/dolphin-emu." + std::to_string(getpid());
+  fd = shm_open(file_name.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600);
+  if (fd == -1)
+  {
+    ERROR_LOG_FMT(MEMMAP, "shm_open failed: {}", strerror(errno));
+    return;
+  }
+  shm_unlink(file_name.c_str());
+  if (ftruncate(fd, size) < 0)
+    ERROR_LOG_FMT(MEMMAP, "Failed to allocate low memory space");
+}
+
+void MemArena::ReleaseSHMSegment()
+{
+  close(fd);
+}
+
+void* MemArena::CreateView(s64 offset, size_t size)
+{
+  return MapInMemoryRegion(offset, size, nullptr);
+}
+
+void MemArena::ReleaseView(void* view, size_t size)
+{
+  UnmapFromMemoryRegion(view, size);
+}
+
+u8* MemArena::ReserveMemoryRegion(size_t memory_size)
+{
+  const int flags = MAP_ANON | MAP_PRIVATE;
+  void* base = mmap(nullptr, memory_size, PROT_NONE, flags, -1, 0);
+  if (base == MAP_FAILED)
+  {
+    PanicAlertFmt("Failed to map enough memory space: {}", LastStrerrorString());
+    return nullptr;
+  }
+  munmap(base, memory_size);
+  return static_cast<u8*>(base);
+}
+
+void MemArena::ReleaseMemoryRegion()
+{
+}
+
+void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base)
+{
+  void* retval = mmap(base, size, PROT_READ | PROT_WRITE,
+                      MAP_SHARED | ((base == nullptr) ? 0 : MAP_FIXED), fd, offset);
+
+  if (retval == MAP_FAILED)
+  {
+    NOTICE_LOG_FMT(MEMMAP, "mmap failed");
+    return nullptr;
+  }
+  else
+  {
+    return retval;
+  }
+}
+
+void MemArena::UnmapFromMemoryRegion(void* view, size_t size)
+{
+  munmap(view, size);
+}
+}  // namespace Common