Revert of mac: Add auto-close and share-read-only functionality to SharedMemory.

base/memory/shared_memory_mac.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/memory/shared_memory.h"
 
 #include <fcntl.h>
 #include <mach/mach_vm.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
 #include "base/files/file_util.h"
 #include "base/files/scoped_file.h"
 #include "base/logging.h"
-#include "base/mac/scoped_mach_vm.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/posix/safe_strerror.h"
 #include "base/process/process_metrics.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/scoped_generic.h"
 #include "base/strings/utf_string_conversions.h"
 
 #if defined(OS_MACOSX)
 #include "base/mac/foundation_util.h"
 #endif  // OS_MACOSX
 
 namespace base {
 
 namespace {
 
-// Returns whether the operation succeeded.
-// |new_handle| is an output variable, populated on success. The caller takes
-// ownership of the underlying memory object.
-// |handle| is the handle to copy.
-// If |handle| is already mapped, |mapped_addr| is its mapped location.
-// Otherwise, |mapped_addr| should be |nullptr|.
-bool MakeMachSharedMemoryHandleReadOnly(SharedMemoryHandle* new_handle,
-                                        SharedMemoryHandle handle,
-                                        void* mapped_addr) {
-  if (!handle.IsValid())
-    return false;
-
-  size_t size;
-  CHECK(handle.GetSize(&size));
-
-  // Map if necessary.
-  void* temp_addr = mapped_addr;
-  base::mac::ScopedMachVM scoper;
-  if (!temp_addr) {
-    // Intentionally lower current prot and max prot to |VM_PROT_READ|.
-    kern_return_t kr = mach_vm_map(
-        mach_task_self(), reinterpret_cast<mach_vm_address_t*>(&temp_addr),
-        size, 0, VM_FLAGS_ANYWHERE, handle.GetMemoryObject(), 0, FALSE,
-        VM_PROT_READ, VM_PROT_READ, VM_INHERIT_NONE);
-    if (kr != KERN_SUCCESS)
-      return false;
-    scoper.reset(reinterpret_cast<vm_address_t>(temp_addr),
-                 mach_vm_round_page(size));
-  }
-
-  // Make new memory object.
-  mach_port_t named_right;
-  kern_return_t kr = mach_make_memory_entry_64(
-      mach_task_self(), reinterpret_cast<memory_object_size_t*>(&size),
-      reinterpret_cast<memory_object_offset_t>(temp_addr), VM_PROT_READ,
-      &named_right, MACH_PORT_NULL);
-  if (kr != KERN_SUCCESS)
-    return false;
-
-  *new_handle = SharedMemoryHandle(named_right, size, base::GetCurrentProcId());
-  return true;
-}
-
 struct ScopedPathUnlinkerTraits {
   static FilePath* InvalidValue() { return nullptr; }
 
   static void Free(FilePath* path) {
     // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466437
     // is fixed.
     tracked_objects::ScopedTracker tracking_profile(
         FROM_HERE_WITH_EXPLICIT_FUNCTION(
             "466437 SharedMemory::Create::Unlink"));
     if (unlink(path->value().c_str()))
@@ skipping 274 matching lines @@
   shm_ = SharedMemoryHandle(mapped_file, false);
   readonly_mapped_file_ = readonly_fd.release();
 
   return true;
 }
 
 bool SharedMemory::ShareToProcessCommon(ProcessHandle process,
                                         SharedMemoryHandle* new_handle,
                                         bool close_self,
                                         ShareMode share_mode) {
-  if (shm_.GetType() == SharedMemoryHandle::MACH) {
-    DCHECK(shm_.IsValid());
-
-    bool success = false;
-    switch (share_mode) {
-      case SHARE_CURRENT_MODE:
-        *new_handle = shm_.Duplicate();
-        success = true;
-        break;
-      case SHARE_READONLY:
-        success = MakeMachSharedMemoryHandleReadOnly(new_handle, shm_, memory_);
-        break;
-    }
-
-    if (success)
-      new_handle->SetOwnershipPassesToIPC(true);
-
-    if (close_self) {
-      Unmap();
-      Close();
-    }
-
-    return success;
-  }
-
+  DCHECK_NE(shm_.GetType(), SharedMemoryHandle::MACH);
   int handle_to_dup = -1;
   switch (share_mode) {
     case SHARE_CURRENT_MODE:
       handle_to_dup = shm_.GetFileDescriptor().fd;
       break;
     case SHARE_READONLY:
       // We could imagine re-opening the file from /dev/fd, but that can't make
       // it readonly on Mac: https://codereview.chromium.org/27265002/#msg10
       CHECK_GE(readonly_mapped_file_, 0);
       handle_to_dup = readonly_mapped_file_;
@@ skipping 10 matching lines @@
 
   if (close_self) {
     Unmap();
     Close();
   }
 
   return true;
 }
 
 }  // namespace base