mac: Some consumers of SharedMemory require a POSIX fd.

There are two implementations of SharedMemory on OSX: Mach and POSIX. Some
consumers of SharedMemory currently require the POSIX implementation. The
default is going to become Mach. This CL updates some consumers of SharedMemory
to force the construction of a POSIX fd-backed SharedMemory region.

BUG=466437

Review URL: https://codereview.chromium.org/1420503010

Cr-Commit-Position: refs/heads/master@{#360502}

base/memory/discardable_shared_memory.cc

@@ -122,8 +122,15 @@ bool DiscardableSharedMemory::CreateAndMap(size_t size) {
   if (!checked_size.IsValid())
     return false;
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  // DiscardableSharedMemory does not yet support a Mach-implementation, so
+  // force the underlying primitive to be a POSIX fd. https://crbug.com/547239.
+  if (!shared_memory_.CreateAndMapAnonymousPosix(checked_size.ValueOrDie()))
+    return false;
+#else
   if (!shared_memory_.CreateAndMapAnonymous(checked_size.ValueOrDie()))
     return false;
+#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 
   mapped_size_ =
       shared_memory_.mapped_size() - AlignToPageSize(sizeof(SharedState));

base/memory/shared_memory_unittest.cc

@@ -316,6 +316,10 @@ TEST(SharedMemoryTest, ShareReadOnly) {
   SharedMemoryCreateOptions options;
   options.size = contents.size();
   options.share_read_only = true;
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  // The Mach functionality is tested in shared_memory_mac_unittest.cc.
+  options.type = SharedMemoryHandle::POSIX;
+#endif
   ASSERT_TRUE(writable_shmem.Create(options));
   ASSERT_TRUE(writable_shmem.Map(options.size));
   memcpy(writable_shmem.memory(), contents.data(), contents.size());
@@ -502,6 +506,10 @@ TEST(SharedMemoryTest, FilePermissionsAnonymous) {
   SharedMemory shared_memory;
   SharedMemoryCreateOptions options;
   options.size = kTestSize;
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  // The Mach functionality is tested in shared_memory_mac_unittest.cc.
+  options.type = SharedMemoryHandle::POSIX;
+#endif
   // Set a file mode creation mask that gives all permissions.
   ScopedUmaskSetter permissive_mask(S_IWGRP | S_IWOTH);
 
@@ -524,6 +532,10 @@ TEST(SharedMemoryTest, FilePermissionsNamed) {
   SharedMemory shared_memory;
   SharedMemoryCreateOptions options;
   options.size = kTestSize;
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  // The Mach functionality is tested in shared_memory_mac_unittest.cc.
+  options.type = SharedMemoryHandle::POSIX;
+#endif
 
   // Set a file mode creation mask that gives all permissions.
   ScopedUmaskSetter permissive_mask(S_IWGRP | S_IWOTH);

components/mus/gles2/mojo_gpu_memory_buffer.cc

@@ -28,8 +28,17 @@ scoped_ptr<gfx::GpuMemoryBuffer> MojoGpuMemoryBufferImpl::Create(
     gfx::BufferUsage usage) {
   size_t bytes = gfx::BufferSizeForBufferFormat(size, format);
   scoped_ptr<base::SharedMemory> shared_memory(new base::SharedMemory);
+
+#if defined(OS_MACOSX)
+  // Mojo IPC does not yet support transfer of Mach primitives, so
+  // force the underlying primitive to be a POSIX fd. https://crbug.com/547243.
+  if (!shared_memory->CreateAnonymousPosix(bytes))
+    return nullptr;
+#else
   if (!shared_memory->CreateAnonymous(bytes))
     return nullptr;
+#endif  // defined(OS_MACOSX)
+
   return make_scoped_ptr<gfx::GpuMemoryBuffer>(
       new MojoGpuMemoryBufferImpl(size, format, shared_memory.Pass()));
 }

components/nacl/browser/nacl_process_host.cc

@@ -944,6 +944,10 @@ bool NaClProcessHost::StartNaClExecution() {
     base::SharedMemoryCreateOptions options;
     options.size = 1;
     options.executable = true;
+
+    // NaCl expects a POSIX fd.
+    options.type = base::SharedMemoryHandle::POSIX;
+
     if (!memory_buffer.Create(options)) {
       DLOG(ERROR) << "Failed to allocate memory buffer";
       return false;

remoting/host/desktop_session_agent.cc

@@ -74,8 +74,16 @@ class DesktopSessionAgent::SharedBuffer : public webrtc::SharedMemory {
                                          size_t size,
                                          int id) {
     scoped_ptr<base::SharedMemory> memory(new base::SharedMemory());
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+    // Remoting does not yet support Mach primitive backed SharedMemory, so
+    // force the underlying primitive to be a POSIX fd.
+    // https://crbug.com/547247.
+    if (!memory->CreateAndMapAnonymousPosix(size))
+      return nullptr;
+#else
     if (!memory->CreateAndMapAnonymous(size))
       return nullptr;
+#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
     return make_scoped_ptr(new SharedBuffer(agent, memory.Pass(), size, id));
   }