From 812cc8b6322fa72982a3084bb3de4bdb564331fe Mon Sep 17 00:00:00 2001
From: "Admiral H. Curtiss" <pikachu025@gmail.com>
Date: Mon, 21 Jun 2021 01:17:07 +0200
Subject: MemArena: Split into three separate files for each OS.

---
 Source/Core/Common/MemArenaAndroid.cpp | 116 +++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 Source/Core/Common/MemArenaAndroid.cpp

(limited to 'Source/Core/Common/MemArenaAndroid.cpp')

diff --git a/Source/Core/Common/MemArenaAndroid.cpp b/Source/Core/Common/MemArenaAndroid.cpp
new file mode 100644
index 0000000000..053b14411f
--- /dev/null
+++ b/Source/Core/Common/MemArenaAndroid.cpp
@@ -0,0 +1,116 @@
+// 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 <dlfcn.h>
+#include <fcntl.h>
+#include <linux/ashmem.h>
+#include <sys/ioctl.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
+{
+#define ASHMEM_DEVICE "/dev/ashmem"
+
+static int AshmemCreateFileMapping(const char* name, size_t size)
+{
+  // ASharedMemory path - works on API >= 26 and falls through on API < 26:
+
+  // We can't call ASharedMemory_create the normal way without increasing the
+  // minimum version requirement to API 26, so we use dlopen/dlsym instead
+  static void* libandroid = dlopen("libandroid.so", RTLD_LAZY | RTLD_LOCAL);
+  static auto shared_memory_create =
+      reinterpret_cast<int (*)(const char*, size_t)>(dlsym(libandroid, "ASharedMemory_create"));
+  if (shared_memory_create)
+    return shared_memory_create(name, size);
+
+  // /dev/ashmem path - works on API < 29:
+
+  int fd, ret;
+  fd = open(ASHMEM_DEVICE, O_RDWR);
+  if (fd < 0)
+    return fd;
+
+  // We don't really care if we can't set the name, it is optional
+  ioctl(fd, ASHMEM_SET_NAME, name);
+
+  ret = ioctl(fd, ASHMEM_SET_SIZE, size);
+  if (ret < 0)
+  {
+    close(fd);
+    NOTICE_LOG_FMT(MEMMAP, "Ashmem returned error: {:#010x}", ret);
+    return ret;
+  }
+  return fd;
+}
+
+void MemArena::GrabSHMSegment(size_t size)
+{
+  fd = AshmemCreateFileMapping(("dolphin-emu." + std::to_string(getpid())).c_str(), size);
+  if (fd < 0)
+    NOTICE_LOG_FMT(MEMMAP, "Ashmem allocation failed");
+}
+
+void MemArena::ReleaseSHMSegment()
+{
+  close(fd);
+}
+
+void* MemArena::CreateView(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::ReleaseView(void* view, size_t size)
+{
+  munmap(view, size);
+}
+
+u8* MemArena::FindMemoryBase()
+{
+#if _ARCH_32
+  const size_t memory_size = 0x31000000;
+#else
+  const size_t memory_size = 0x400000000;
+#endif
+
+  // Android 4.3 changed how mmap works.
+  // if we map it private and then munmap it, we can't use the base returned.
+  // This may be due to changes in them to support a full SELinux implementation.
+  const int flags = MAP_ANON | MAP_SHARED;
+  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);
+}
+}  // namespace Common
-- 
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