Curtain mode implementation for Mac OS X.

This implements the basic curtain-mode functionality:
* Switch out the active session on connection (if necessary--it doesn't do this if the session is at the login screen or already switched out)
* Close all connections if the session becomes active again (for example, if someone logs into it at the console).

It doesn't solve the problem of launchd starting a new instance of the server when we switch out. There will be a follow-up CL to address that.

BUG=110111


Review URL: https://chromiumcodereview.appspot.com/10823215

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150746 0039d316-1c4b-4281-b951-d872f2087c98

remoting/host/curtain_mode_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 "remoting/host/curtain_mode_mac.h"
+
+#include <ApplicationServices/ApplicationServices.h>
+#include <Security/Security.h>
+
+#include "base/logging.h"
+#include "base/mac/scoped_cftyperef.h"
+
+namespace {
+const char* kCGSessionPath =
+    "/System/Library/CoreServices/Menu Extras/User.menu/Contents/Resources/"
+    "CGSession";
+}
+
+namespace remoting {
+
+CurtainMode::CurtainMode() : event_handler_(NULL) {
+}
+
+CurtainMode::~CurtainMode() {
+  if (event_handler_) {
+    RemoveEventHandler(event_handler_);
+  }
+}
+
+bool CurtainMode::Init(const base::Closure& on_session_activate) {
+  DCHECK(on_session_activate_.is_null());
+  on_session_activate_ = on_session_activate;
+  EventTypeSpec event;
+  event.eventClass = kEventClassSystem;
+  event.eventKind = kEventSystemUserSessionActivated;
+  OSStatus result = InstallApplicationEventHandler(
+      NewEventHandlerUPP(SessionActivateHandler), 1, &event, this,
+      &event_handler_);
+  return result == noErr;
+}
+
+void CurtainMode::OnClientAuthenticated(const std::string& jid) {
+  // If the current session is attached to the console and is not showing
+  // the logon screen then switch it out to ensure privacy.
+  base::mac::ScopedCFTypeRef<CFDictionaryRef> session(
+      CGSessionCopyCurrentDictionary());
+  const void* on_console = CFDictionaryGetValue(session,
+                                                kCGSessionOnConsoleKey);
+  const void* logged_in = CFDictionaryGetValue(session, kCGSessionLoginDoneKey);
+  if (logged_in == kCFBooleanTrue && on_console == kCFBooleanTrue) {
+    pid_t child = fork();
+    if (child == 0) {
+      execl(kCGSessionPath, kCGSessionPath, "-suspend", NULL);
+      _exit(1);
+    } else if (child > 0) {
+      int status = 0;
+      waitpid(child, &status, 0);
+    }
+  }
+}
+
+OSStatus CurtainMode::SessionActivateHandler(EventHandlerCallRef handler,
+                                             EventRef event,
+                                             void* user_data) {
+  CurtainMode* self = static_cast<CurtainMode*>(user_data);
+  self->OnSessionActivate();
+  return noErr;
+}
+
+void CurtainMode::OnSessionActivate() {
+  if (!on_session_activate_.is_null()) {
+    on_session_activate_.Run();
+  }
+}
+
+}  // namespace remoting

remoting/host/curtain_mode_mac.h

+// 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.
+
+#ifndef REMOTING_HOST_CURTAIN_MODE_MAC_H_
+#define REMOTING_HOST_CURTAIN_MODE_MAC_H_
+
+#include <Carbon/Carbon.h>
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "remoting/host/host_status_observer.h"
+
+namespace remoting {
+
+class CurtainMode : public HostStatusObserver {
+ public:
+  CurtainMode();
+  virtual ~CurtainMode();
+
+  // Set the callback to be invoked when the switched-out remote session is
+  // switched back to the console.  Typically, remote connections should be
+  // closed in this event to make sure that only one connection (console or
+  // remote) exists to a session at any time to ensure privacy.  Note that
+  // only the session's owner (or someone who knows the owner's password)
+  // can attach it to the console, so this is safe.
+  bool Init(const base::Closure& on_session_activate);
+
+  // Overridden from HostStatusObserver
+  virtual void OnClientAuthenticated(const std::string& jid) OVERRIDE;
+
+ private:
+  static OSStatus SessionActivateHandler(EventHandlerCallRef handler,
+                                         EventRef event,
+                                         void* user_data);
+  void OnSessionActivate();
+
+  base::Closure on_session_activate_;
+  EventHandlerRef event_handler_;
+};
+
+}
+
+#endif

remoting/host/remoting_me2me_host.cc

@@ -51,6 +51,7 @@
 
 #if defined(OS_MACOSX)
 #include "base/mac/scoped_nsautorelease_pool.h"
+#include "remoting/host/curtain_mode_mac.h"
 #include "remoting/host/sighup_listener_mac.h"
 #endif
 // N.B. OS_WIN is defined by including src/base headers.
@@ -446,6 +447,12 @@ class HostProcess
                           base::Unretained(this)));
 #endif
 
+#if defined(OS_MACOSX)
+    curtain_.Init(base::Bind(&HostProcess::OnDisconnectRequested,
+                             base::Unretained(this)));
+    host_->AddStatusObserver(&curtain_);
+#endif
+
     host_->Start();
 
     CreateAuthenticatorFactory();
@@ -558,6 +565,10 @@ class HostProcess
   scoped_refptr<ChromotingHost> host_;
 
   int exit_code_;
+
+#if defined(OS_MACOSX)
+    remoting::CurtainMode curtain_;
+#endif
 };
 
 }  // namespace remoting

remoting/remoting.gyp

@@ -1468,6 +1468,8 @@
         'host/remoting_me2me_host.cc',
         'host/usage_stats_consent.h',
         'host/usage_stats_consent_win.cc',
+        'host/curtain_mode_mac.h',
+        'host/curtain_mode_mac.cc',
       ],
       'conditions': [
         ['OS=="mac"', {