Move MachBroker to content.

BUG=76697
Review URL: http://codereview.chromium.org/7232003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90236 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 229 insertions, 0 deletions

diff --git a/content/browser/mach_broker_mac.cc b/content/browser/mach_broker_mac.cc
new file mode 100644
index 0000000..dca1b11
--- /dev/null
+++ b/content/browser/mach_broker_mac.cc
@@ -0,0 +1,229 @@
+// Copyright (c) 2011 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 "content/browser/mach_broker_mac.h"
+
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/mac/foundation_util.h"
+#include "base/mach_ipc_mac.h"
+#include "base/string_util.h"
+#include "base/sys_string_conversions.h"
+#include "base/threading/platform_thread.h"
+#include "content/browser/browser_thread.h"
+#include "content/browser/renderer_host/render_process_host.h"
+#include "content/common/child_process_info.h"
+#include "content/common/content_switches.h"
+#include "content/common/notification_service.h"
+
+namespace {
+// Prints a string representation of a Mach error code.
+std::string MachErrorCode(kern_return_t err) {
+  return StringPrintf("0x%x %s", err, mach_error_string(err));
+}
+}  // namespace
+
+// Required because notifications happen on the UI thread.
+class RegisterNotificationTask : public Task {
+ public:
+  RegisterNotificationTask(
+      MachBroker* broker)
+      : broker_(broker) { }
+
+  virtual void Run() {
+    broker_->registrar_.Add(broker_,
+        NotificationType::RENDERER_PROCESS_CLOSED,
+        NotificationService::AllSources());
+    broker_->registrar_.Add(broker_,
+        NotificationType::RENDERER_PROCESS_TERMINATED,
+        NotificationService::AllSources());
+    broker_->registrar_.Add(broker_,
+        NotificationType::CHILD_PROCESS_CRASHED,
+        NotificationService::AllSources());
+    broker_->registrar_.Add(broker_,
+        NotificationType::CHILD_PROCESS_HOST_DISCONNECTED,
+        NotificationService::AllSources());
+  }
+
+ private:
+  MachBroker* broker_;
+  DISALLOW_COPY_AND_ASSIGN(RegisterNotificationTask);
+};
+
+class MachListenerThreadDelegate : public base::PlatformThread::Delegate {
+ public:
+  MachListenerThreadDelegate(MachBroker* broker) : broker_(broker) {
+    DCHECK(broker_);
+    std::string port_name = MachBroker::GetMachPortName();
+
+    // Create the receive port in the constructor, not in ThreadMain().  It is
+    // important to create and register the receive port before starting the
+    // thread so that child processes will always have someone who's listening.
+    receive_port_.reset(new base::ReceivePort(port_name.c_str()));
+  }
+
+  // Implement |PlatformThread::Delegate|.
+  void ThreadMain() {
+    base::MachReceiveMessage message;
+    kern_return_t err;
+    while ((err = receive_port_->WaitForMessage(&message,
+                                                MACH_MSG_TIMEOUT_NONE)) ==
+           KERN_SUCCESS) {
+      // 0 was the secret message id.  Reject any messages that don't have it.
+      if (message.GetMessageID() != 0) {
+        LOG(ERROR) << "Received message with incorrect id: "
+                   << message.GetMessageID();
+        continue;
+      }
+
+      const task_t child_task = message.GetTranslatedPort(0);
+      if (child_task == MACH_PORT_NULL) {
+        LOG(ERROR) << "parent GetTranslatedPort(0) failed.";
+        continue;
+      }
+
+      // It is possible for the child process to die after the call to
+      // |pid_for_task()| but before the call to |FinalizePid()|.  To prevent
+      // leaking MachBroker map entries in this case, lock around both these
+      // calls.  If the child dies, the death notification will be processed
+      // after the call to FinalizePid(), ensuring proper cleanup.
+      base::AutoLock lock(broker_->GetLock());
+
+      int pid;
+      err = pid_for_task(child_task, &pid);
+      if (err == KERN_SUCCESS) {
+        broker_->FinalizePid(pid,
+                             MachBroker::MachInfo().SetTask(child_task));
+      } else {
+        LOG(ERROR) << "Error getting pid for task " << child_task
+                   << ": " << MachErrorCode(err);
+      }
+    }
+
+    LOG(ERROR) << "Mach listener thread exiting; "
+               << "parent WaitForMessage() likely failed: "
+               << MachErrorCode(err);
+  }
+
+ private:
+  // The Mach port to listen on.  Created on thread startup.
+  scoped_ptr<base::ReceivePort> receive_port_;
+
+  // The MachBroker to use when new child task rights are received.  Can be
+  // NULL.
+  MachBroker* broker_;  // weak
+
+  DISALLOW_COPY_AND_ASSIGN(MachListenerThreadDelegate);
+};
+
+// Returns the global MachBroker.
+MachBroker* MachBroker::GetInstance() {
+  return Singleton<MachBroker, LeakySingletonTraits<MachBroker> >::get();
+}
+
+MachBroker::MachBroker() : listener_thread_started_(false) {
+}
+
+MachBroker::~MachBroker() {}
+
+void MachBroker::PrepareForFork() {
+  if (!listener_thread_started_) {
+    listener_thread_started_ = true;
+
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE, new RegisterNotificationTask(this));
+
+    // Intentional leak.  This thread is never joined or reaped.
+    base::PlatformThread::CreateNonJoinable(
+        0, new MachListenerThreadDelegate(this));
+  }
+}
+
+// Adds a placeholder to the map for the given pid with MACH_PORT_NULL.
+void MachBroker::AddPlaceholderForPid(base::ProcessHandle pid) {
+  lock_.AssertAcquired();
+
+  MachInfo mach_info;
+  DCHECK_EQ(0u, mach_map_.count(pid));
+  mach_map_[pid] = mach_info;
+}
+
+// Updates the mapping for |pid| to include the given |mach_info|.
+void MachBroker::FinalizePid(base::ProcessHandle pid,
+                             const MachInfo& mach_info) {
+  lock_.AssertAcquired();
+
+  const int count = mach_map_.count(pid);
+  if (count == 0) {
+    // Do nothing for unknown pids.
+    LOG(ERROR) << "Unknown process " << pid << " is sending Mach IPC messages!";
+    return;
+  }
+
+  DCHECK_EQ(1, count);
+  DCHECK(mach_map_[pid].mach_task_ == MACH_PORT_NULL);
+  if (mach_map_[pid].mach_task_ == MACH_PORT_NULL)
+    mach_map_[pid] = mach_info;
+}
+
+// Removes all mappings belonging to |pid| from the broker.
+void MachBroker::InvalidatePid(base::ProcessHandle pid) {
+  base::AutoLock lock(lock_);
+  MachBroker::MachMap::iterator it = mach_map_.find(pid);
+  if (it == mach_map_.end())
+    return;
+
+  kern_return_t kr = mach_port_deallocate(mach_task_self(),
+                                          it->second.mach_task_);
+  LOG_IF(WARNING, kr != KERN_SUCCESS)
+     << "Failed to mach_port_deallocate mach task " << it->second.mach_task_
+     << ", error " << MachErrorCode(kr);
+  mach_map_.erase(it);
+}
+
+base::Lock& MachBroker::GetLock() {
+  return lock_;
+}
+
+// Returns the mach task belonging to |pid|.
+mach_port_t MachBroker::TaskForPid(base::ProcessHandle pid) const {
+  base::AutoLock lock(lock_);
+  MachBroker::MachMap::const_iterator it = mach_map_.find(pid);
+  if (it == mach_map_.end())
+    return MACH_PORT_NULL;
+  return it->second.mach_task_;
+}
+
+void MachBroker::Observe(NotificationType type,
+                         const NotificationSource& source,
+                         const NotificationDetails& details) {
+  // TODO(rohitrao): These notifications do not always carry the proper PIDs,
+  // especially when the renderer is already gone or has crashed.  Find a better
+  // way to listen for child process deaths.  http://crbug.com/55734
+  base::ProcessHandle handle = 0;
+  switch (type.value) {
+    case NotificationType::RENDERER_PROCESS_CLOSED:
+    case NotificationType::RENDERER_PROCESS_TERMINATED:
+      handle = Source<RenderProcessHost>(source)->GetHandle();
+      break;
+    case NotificationType::CHILD_PROCESS_CRASHED:
+    case NotificationType::CHILD_PROCESS_HOST_DISCONNECTED:
+      handle = Details<ChildProcessInfo>(details)->handle();
+      break;
+    default:
+      NOTREACHED() << "Unexpected notification";
+      break;
+  }
+  InvalidatePid(handle);
+}
+
+// static
+std::string MachBroker::GetMachPortName() {
+  const CommandLine* command_line = CommandLine::ForCurrentProcess();
+  const bool is_child = command_line->HasSwitch(switches::kProcessType);
+
+  // In non-browser (child) processes, use the parent's pid.
+  const pid_t pid = is_child ? getppid() : getpid();
+  return StringPrintf("%s.rohitfork.%d", base::mac::BaseBundleID(), pid);
+}