Show all system process in the task_manager.

chrome/browser/chromeos/arc/arc_process_service.cc

 // Copyright 2016 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.
 //
 // The main point of this class is to cache ARC proc nspid<->pid mapping
 // globally. Since the calculation is costly, a dedicated worker thread is
 // used. All read/write of its internal data structure (i.e., the mapping)
 // should be on this thread.
 
 #include "chrome/browser/chromeos/arc/arc_process_service.h"
 
 #include <queue>
 #include <set>
 #include <string>
 
 #include "base/process/process.h"
 #include "base/process/process_iterator.h"
 #include "base/task_runner_util.h"
 #include "base/trace_event/trace_event.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace arc {
 
 namespace {
 
 const char kSequenceToken[] = "arc_process_service";

[Yusuke Sato, 2016/06/02 21:50:11]

s/const/constexpr/

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

 
 // Weak pointer.  This class is owned by ArcServiceManager.
 ArcProcessService* g_arc_process_service = nullptr;
 
 }  // namespace
 
 using base::kNullProcessId;
 using base::Process;
 using base::ProcessId;
 using base::SequencedWorkerPool;
@@ skipping 33 matching lines @@
       FROM_HERE,
       base::Bind(&ArcProcessService::Reset,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 void ArcProcessService::Reset() {
   DCHECK(thread_checker_.CalledOnValidThread());
   nspid_to_pid_.clear();
 }
 
-bool ArcProcessService::RequestProcessList(
+bool ArcProcessService::RequestSystemProcessList(

[cylee1, 2016/06/02 20:58:45]

nit: can you try to consolidate the logic here and in OnReceiveProcessList ?
For example, creating a function like PostTaskToOwnThreadAndReply(task,
callback).

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

     RequestProcessListCallback callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
+  auto ret_processes = new vector<ArcProcess>();
+  auto runner = worker_pool_->GetSequencedTaskRunner(

[Yusuke Sato, 2016/06/02 21:50:11]

Why does this have to be sequenced, btw?

[Hsu-Cheng, 2016/06/29 10:33:57]

The pool size here is 1 and this is for avoid running delayed jobs at the same
time. 

+      worker_pool_->GetNamedSequenceToken(kSequenceToken));
+  runner->PostTaskAndReply(
+      FROM_HERE, base::Bind(&ArcProcessService::FetchAndReturnSystemProcessList,
+                            weak_ptr_factory_.GetWeakPtr(),
+                            base::Unretained(ret_processes)),
+      base::Bind(&ArcProcessService::CallbackRelay,
+                 weak_ptr_factory_.GetWeakPtr(), callback,
+                 base::Owned(ret_processes)));
+  return true;

[cylee1, 2016/06/02 20:58:45]

Always return true?

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+}
+
+void ArcProcessService::FetchAndReturnSystemProcessList(

[cylee1, 2016/06/02 20:58:44]

Maybe GetArcSystemProcessList

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+    vector<ArcProcess>* ret_processes) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  const base::ProcessIterator::ProcessEntries& entry_list =
+      base::ProcessIterator(nullptr).Snapshot();
+  ProcessId arc_init_pid = GetArcInitProcessId(entry_list);

[cylee1, 2016/06/02 20:58:45]

You should check if it's kNullProcessId before doing the next step.

[Hsu-Cheng, 2016/06/29 10:33:56]

Done.

+
+  // Enumerate the child processes of ARC init for gaterhing ARC system procces

[cylee1, 2016/06/02 20:58:44]

nit: gathering
nit: processes

I think you should add comment somewhere to note your definition of "system
process" is "direct children of init process" and why so.

[Hsu-Cheng, 2016/06/29 10:33:57]

Added system process definition in arc_process_service.h 

+  for (const base::ProcessEntry& entry : entry_list) {
+    std::string process_name =

[cylee1, 2016/06/02 20:58:44]

why not get process_name inside the if at line 109?

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+        !entry.cmd_line_args().empty() ? entry.cmd_line_args()[0] : "";
+    if (entry.parent_pid() == arc_init_pid) {

[Yusuke Sato, 2016/06/02 21:50:11]

This will only detect direct children of the init process, right? Is that good
enough? For example, installd might fork/execute dex2oat which might take a few
minutes to finish worst case, but with this logic, the dex2oat process won't
show up in Task Manager.

[Hsu-Cheng, 2016/06/29 10:33:57]

You are right. I miss the case. I will make a new change for this. TODO is
added.

+      ProcessId child_pid = entry.pid();
+      ProcessId child_nspid = base::Process(child_pid).GetPidInNamespace();
+      if (child_nspid != kNullProcessId) {
+        ArcProcess arc_process = {child_nspid, child_pid, process_name,

[Yusuke Sato, 2016/06/02 21:50:11]

This no longer compiles once you rebase your Chromium copy to tot because
r397310 made ArcProcess move-only.

 ArcProcess arc_process(child_nspid, child_pid, process_name,
mojom::ProcessState::PERSISTENT);
 ret_processes->push_back(std::move(arc_process));

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+                                  mojom::ProcessState::PERSISTENT};
+        ret_processes->push_back(arc_process);
+      }
+    }
+  }
+}
+
+bool ArcProcessService::RequestAppProcessList(
+    RequestProcessListCallback callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
   arc::mojom::ProcessInstance* process_instance =
       arc_bridge_service()->process_instance();
   if (!process_instance) {
     return false;
   }
   process_instance->RequestProcessList(
       base::Bind(&ArcProcessService::OnReceiveProcessList,
                  weak_ptr_factory_.GetWeakPtr(),
                  callback));
   return true;
@@ skipping 100 matching lines @@
   // processes may have the same nspid. We need to get the proper subset of
   // processes to create correct nspid -> pid map.
 
   // Construct the process tree.
   // NB: This can contain a loop in case of race conditions.
   map<ProcessId, vector<ProcessId> > process_tree;
   for (const base::ProcessEntry& entry : entry_list)
     process_tree[entry.parent_pid()].push_back(entry.pid());
 
   // Find the ARC init process.
-  ProcessId arc_init_pid = kNullProcessId;
-  for (const base::ProcessEntry& entry : entry_list) {
-    // TODO(nya): Add more constraints to avoid mismatches.
-    std::string process_name =
-        !entry.cmd_line_args().empty() ? entry.cmd_line_args()[0] : "";
-    if (process_name == "/init") {
-      arc_init_pid = entry.pid();
-      break;
-    }
-  }
+  ProcessId arc_init_pid = GetArcInitProcessId(entry_list);
 
   // Enumerate all processes under ARC init and create nspid -> pid map.
   if (arc_init_pid != kNullProcessId) {
     std::queue<ProcessId> queue;
     std::set<ProcessId> visited;
     queue.push(arc_init_pid);
     while (!queue.empty()) {
       ProcessId pid = queue.front();
       queue.pop();
       // Do not visit the same process twice. Otherwise we may enter an infinite
@@ skipping 10 matching lines @@
       if (nspid != kNullProcessId &&
           nspid_to_pid_.find(nspid) != nspid_to_pid_.end())
         nspid_to_pid_[nspid] = pid;
 
       for (ProcessId child_pid : process_tree[pid])
         queue.push(child_pid);
     }
   }
 }
 
+ProcessId ArcProcessService::GetArcInitProcessId(
+    const base::ProcessIterator::ProcessEntries& entry_list) {
+  // Find the ARC init process.
+  for (const base::ProcessEntry& entry : entry_list) {
+    // TODO(nya): Add more constraints to avoid mismatches.
+    std::string process_name =
+        !entry.cmd_line_args().empty() ? entry.cmd_line_args()[0] : "";
+    if (process_name == "/init") {
+      return entry.pid();
+    }
+  }
+  return kNullProcessId;
+}
+
 }  // namespace arc