1 files changed, 55 insertions, 0 deletions
diff --git a/ipc/glue/SharedMemory_posix.cpp b/ipc/glue/SharedMemory_posix.cpp
new file mode 100644
index 0000000000..b634058945
--- /dev/null
+++ b/ipc/glue/SharedMemory_posix.cpp
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/mman.h>  // mprotect
+#include <unistd.h>    // sysconf
+
+#include "mozilla/ipc/SharedMemory.h"
+
+#if defined(XP_MACOSX) && defined(__x86_64__)
+#  include "prenv.h"
+#endif
+
+namespace mozilla {
+namespace ipc {
+
+#if defined(XP_MACOSX) && defined(__x86_64__)
+std::atomic<size_t> sPageSizeOverride = 0;
+#endif
+
+void SharedMemory::SystemProtect(char* aAddr, size_t aSize, int aRights) {
+  if (!SystemProtectFallible(aAddr, aSize, aRights)) {
+    MOZ_CRASH("can't mprotect()");
+  }
+}
+
+bool SharedMemory::SystemProtectFallible(char* aAddr, size_t aSize,
+                                         int aRights) {
+  int flags = 0;
+  if (aRights & RightsRead) flags |= PROT_READ;
+  if (aRights & RightsWrite) flags |= PROT_WRITE;
+  if (RightsNone == aRights) flags = PROT_NONE;
+
+  return 0 == mprotect(aAddr, aSize, flags);
+}
+
+size_t SharedMemory::SystemPageSize() {
+#if defined(XP_MACOSX) && defined(__x86_64__)
+  if (sPageSizeOverride == 0) {
+    if (PR_GetEnv("MOZ_SHMEM_PAGESIZE_16K")) {
+      sPageSizeOverride = 16 * 1024;
+    } else {
+      sPageSizeOverride = sysconf(_SC_PAGESIZE);
+    }
+  }
+  return sPageSizeOverride;
+#else
+  return sysconf(_SC_PAGESIZE);
+#endif
+}
+
+}  // namespace ipc
+}  // namespace mozilla