ipc: Slight change to GetSenderWithProcessId().

ipc/attachment_broker_privileged_mac.cc

 // Copyright 2015 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 "ipc/attachment_broker_privileged_mac.h"
 
 #include "base/mac/scoped_mach_port.h"
 #include "base/memory/shared_memory.h"
 #include "base/process/port_provider_mac.h"
 #include "base/process/process.h"
+#include "base/synchronization/lock.h"
 #include "ipc/attachment_broker_messages.h"
 #include "ipc/brokerable_attachment.h"
 #include "ipc/ipc_channel.h"
 #include "ipc/mach_port_attachment_mac.h"
 
 namespace {
 
 // Struct for sending a complex Mach message.
 struct MachSendComplexMessage {
   mach_msg_header_t header;
@@ skipping 182 matching lines @@
       new internal::MachPortAttachmentMac(wire_format));
   HandleReceivedAttachment(attachment);
 }
 
 bool AttachmentBrokerPrivilegedMac::RouteWireFormatToAnother(
     const MachPortWireFormat& wire_format) {
   DCHECK_NE(wire_format.destination_process, base::Process::Current().Pid());
 
   // Another process is the destination.
   base::ProcessId dest = wire_format.destination_process;
+  base::AutoLock auto_lock(*get_lock());
   Sender* sender = GetSenderWithProcessId(dest);
   if (!sender) {
     // Assuming that this message was not sent from a malicious process, the
     // channel endpoint that would have received this message will block
     // forever.
     LOG(ERROR) << "Failed to deliver brokerable attachment to process with id: "
                << dest;
     LogError(DESTINATION_NOT_FOUND);
     return false;
   }
@@ skipping 89 matching lines @@
     base::ProcessId pid) {
   base::AutoLock l(precursors_lock_);
   auto it = precursors_.find(pid);
   if (it == precursors_.end())
     return;
 
   // Whether this process is the destination process.
   bool to_self = pid == base::GetCurrentProcId();
 
   if (!to_self) {
+    base::AutoLock auto_lock(*get_lock());
     if (!GetSenderWithProcessId(pid)) {
       // If there is no sender, then the destination process is no longer
       // running, or never existed to begin with.
       LogError(DESTINATION_NOT_FOUND);
       delete it->second;
       precursors_.erase(it);
       return;
     }
   }
 
@@ skipping 48 matching lines @@
       pid, base::mac::ScopedMachSendRight(port.release()), id));
 }
 
 void AttachmentBrokerPrivilegedMac::ProcessExtractorsForProcess(
     base::ProcessId pid) {
   base::AutoLock l(extractors_lock_);
   auto it = extractors_.find(pid);
   if (it == extractors_.end())
     return;
 
-  if (!GetSenderWithProcessId(pid)) {
-    // If there is no sender, then the source process is no longer running.
-    LogError(ERROR_SOURCE_NOT_FOUND);
-    delete it->second;
-    extractors_.erase(it);
-    return;
+  {
+    base::AutoLock auto_lock(*get_lock());
+    if (!GetSenderWithProcessId(pid)) {
+      // If there is no sender, then the source process is no longer running.
+      LogError(ERROR_SOURCE_NOT_FOUND);
+      delete it->second;
+      extractors_.erase(it);
+      return;
+    }
   }
 
   mach_port_t task_port = port_provider_->TaskForPid(pid);
 
   // It's possible that the source process has not yet provided the privileged
   // process with its task port.
   if (task_port == MACH_PORT_NULL)
     return;
 
   while (!it->second->empty()) {
@@ skipping 28 matching lines @@
 
   auto it = extractors_.find(source_pid);
   if (it == extractors_.end())
     extractors_[source_pid] = new ScopedVector<AttachmentExtractor>;
 
   extractors_[source_pid]->push_back(
       new AttachmentExtractor(source_pid, dest_pid, port, id));
 }
 
 }  // namespace IPC