NaCl: Send fatal log messages via shared memory.

components/nacl/browser/nacl_process_host.cc

Index: components/nacl/browser/nacl_process_host.cc
diff --git a/components/nacl/browser/nacl_process_host.cc b/components/nacl/browser/nacl_process_host.cc
index 7005a664553fe995ebeae7f622af214b9ecfbe53..2da1995e14baa55ed8fbf644817247b8d3c2cafe 100644
--- a/components/nacl/browser/nacl_process_host.cc
+++ b/components/nacl/browser/nacl_process_host.cc
@@ -336,6 +336,11 @@ NaClProcessHost::~NaClProcessHost() {
     NaClBrokerService::GetInstance()->OnLoaderDied();
   }
 #endif
+
+  if (base::SharedMemory::IsHandleValid(crash_info_shmem_plugin_handle_))
+    base::SharedMemory::CloseHandle(crash_info_shmem_plugin_handle_);

[Mark Seaborn, 2014/08/17 20:13:45]

Is this a handle in another process's handle namespace?  This looks unsafe on
Windows.

[teravest, 2014/08/18 16:16:26]

Good point. I've changed this to only share the shared memory before sending
messages to the plugin or the renderer. This means that the object hangs around
longer in the browser, but keeping an extra handle in that process doesn't seem
terrible.

+  if (base::SharedMemory::IsHandleValid(crash_info_shmem_renderer_handle_))
+    base::SharedMemory::CloseHandle(crash_info_shmem_renderer_handle_);
 }
 
 void NaClProcessHost::OnProcessCrashed(int exit_status) {
@@ -474,6 +479,18 @@ void NaClProcessHost::Launch(
     SetCloseOnExec(pair[1]);
   }
 
+  // Create a shared memory region that the renderer and plugin share for
+  // reporting crash information.
+  {
+    base::SharedMemory crash_info_shmem;
+    if (crash_info_shmem.CreateAnonymous(kNaClCrashInfoShmemSize)) {
+      crash_info_shmem.ShareToProcess(process_->GetData().handle,

[Mark Seaborn, 2014/08/17 20:13:45]

Should this check for an error?

[teravest, 2014/08/18 16:16:26]

I've added error checking at the ShareToProcess() calls.

+                                      &crash_info_shmem_plugin_handle_);
+      crash_info_shmem.ShareToProcess(nacl_host_message_filter_->PeerHandle(),
+                                      &crash_info_shmem_renderer_handle_);
+    }
+  }
+
   // Launch the process
   if (!LaunchSelLdr()) {
     delete this;
@@ -742,9 +759,11 @@ bool NaClProcessHost::ReplyToRenderer(
                        trusted_channel_handle,
                        manifest_service_channel_handle,
                        base::GetProcId(data.handle),
-                       data.id),
+                       data.id,
+                       crash_info_shmem_renderer_handle_),
       std::string() /* error_message */);
   internal_->socket_for_renderer = NACL_INVALID_HANDLE;
+  crash_info_shmem_renderer_handle_ = base::SharedMemory::NULLHandle();
   return true;
 }
 
@@ -900,6 +919,9 @@ bool NaClProcessHost::StartNaClExecution() {
   params.nexe_file = IPC::TakeFileHandleForProcess(nexe_file_.Pass(),
                                                    process_->GetData().handle);
 
+  params.crash_info_shmem_handle = crash_info_shmem_plugin_handle_;
+  crash_info_shmem_plugin_handle_ = base::SharedMemory::NULLHandle();
+
   process_->Send(new NaClProcessMsg_Start(params));
   return true;
 }