process_win.cc revision 58e6fbe4ee35d65e14b626c557d37565bf8ad179 
1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/process/process.h"
6
7#include "base/logging.h"
8#include "base/memory/scoped_ptr.h"
9#include "base/win/windows_version.h"
10
11namespace base {
12
13void Process::Close() {
14  if (!process_)
15    return;
16
17  // Don't call CloseHandle on a pseudo-handle.
18  if (process_ != ::GetCurrentProcess())
19    ::CloseHandle(process_);
20
21  process_ = NULL;
22}
23
24void Process::Terminate(int result_code) {
25  if (!process_)
26    return;
27
28  // Call NtTerminateProcess directly, without going through the import table,
29  // which might have been hooked with a buggy replacement by third party
30  // software. http://crbug.com/81449.
31  HMODULE module = GetModuleHandle(L"ntdll.dll");
32  typedef UINT (WINAPI *TerminateProcessPtr)(HANDLE handle, UINT code);
33  TerminateProcessPtr terminate_process = reinterpret_cast<TerminateProcessPtr>(
34      GetProcAddress(module, "NtTerminateProcess"));
35  terminate_process(process_, result_code);
36}
37
38bool Process::IsProcessBackgrounded() const {
39  if (!process_)
40    return false;  // Failure case.
41  DWORD priority = GetPriority();
42  if (priority == 0)
43    return false;  // Failure case.
44  return ((priority == BELOW_NORMAL_PRIORITY_CLASS) ||
45          (priority == IDLE_PRIORITY_CLASS));
46}
47
48bool Process::SetProcessBackgrounded(bool value) {
49  if (!process_)
50    return false;
51  // Vista and above introduce a real background mode, which not only
52  // sets the priority class on the threads but also on the IO generated
53  // by it. Unfortunately it can only be set for the calling process.
54  DWORD priority;
55  if ((base::win::GetVersion() >= base::win::VERSION_VISTA) &&
56      (process_ == ::GetCurrentProcess())) {
57    priority = value ? PROCESS_MODE_BACKGROUND_BEGIN :
58                       PROCESS_MODE_BACKGROUND_END;
59  } else {
60    priority = value ? BELOW_NORMAL_PRIORITY_CLASS : NORMAL_PRIORITY_CLASS;
61  }
62
63  return (::SetPriorityClass(process_, priority) != 0);
64}
65
66ProcessId Process::pid() const {
67  if (process_ == 0)
68    return 0;
69
70  return GetProcId(process_);
71}
72
73bool Process::is_current() const {
74  return process_ == GetCurrentProcess();
75}
76
77// static
78Process Process::Current() {
79  return Process(::GetCurrentProcess());
80}
81
82// static
83bool Process::CanBackgroundProcesses() {
84  return true;
85}
86
87int Process::GetPriority() const {
88  DCHECK(process_);
89  return ::GetPriorityClass(process_);
90}
91
92}  // namespace base
93