1// Copyright (c) 2012 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/threading/platform_thread.h"
6
7#include <errno.h>
8#include <sched.h>
9
10#include "base/lazy_instance.h"
11#include "base/logging.h"
12#include "base/memory/scoped_ptr.h"
13#include "base/safe_strerror_posix.h"
14#include "base/threading/thread_id_name_manager.h"
15#include "base/threading/thread_restrictions.h"
16#include "base/tracked_objects.h"
17
18#if !defined(OS_NACL)
19#include <sys/prctl.h>
20#include <sys/resource.h>
21#include <sys/syscall.h>
22#include <sys/time.h>
23#include <unistd.h>
24#endif
25
26namespace base {
27
28namespace {
29
30int ThreadNiceValue(ThreadPriority priority) {
31  switch (priority) {
32    case kThreadPriority_RealtimeAudio:
33      return -10;
34    case kThreadPriority_Background:
35      return 10;
36    case kThreadPriority_Normal:
37      return 0;
38    case kThreadPriority_Display:
39      return -6;
40    default:
41      NOTREACHED() << "Unknown priority.";
42      return 0;
43  }
44}
45
46}  // namespace
47
48// static
49void PlatformThread::SetName(const char* name) {
50  ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
51  tracked_objects::ThreadData::InitializeThreadContext(name);
52
53#if !defined(OS_NACL)
54  // On linux we can get the thread names to show up in the debugger by setting
55  // the process name for the LWP.  We don't want to do this for the main
56  // thread because that would rename the process, causing tools like killall
57  // to stop working.
58  if (PlatformThread::CurrentId() == getpid())
59    return;
60
61  // http://0pointer.de/blog/projects/name-your-threads.html
62  // Set the name for the LWP (which gets truncated to 15 characters).
63  // Note that glibc also has a 'pthread_setname_np' api, but it may not be
64  // available everywhere and it's only benefit over using prctl directly is
65  // that it can set the name of threads other than the current thread.
66  int err = prctl(PR_SET_NAME, name);
67  // We expect EPERM failures in sandboxed processes, just ignore those.
68  if (err < 0 && errno != EPERM)
69    DPLOG(ERROR) << "prctl(PR_SET_NAME)";
70#endif  //  !defined(OS_NACL)
71}
72
73// static
74void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
75                                       ThreadPriority priority) {
76#if !defined(OS_NACL)
77  if (priority == kThreadPriority_RealtimeAudio) {
78    const struct sched_param kRealTimePrio = {8};
79    if (pthread_setschedparam(pthread_self(), SCHED_RR, &kRealTimePrio) == 0) {
80      // Got real time priority, no need to set nice level.
81      return;
82    }
83  }
84
85  // setpriority(2) should change the whole thread group's (i.e. process)
86  // priority. however, on linux it will only change the target thread's
87  // priority. see the bugs section in
88  // http://man7.org/linux/man-pages/man2/getpriority.2.html.
89  // we prefer using 0 rather than the current thread id since they are
90  // equivalent but it makes sandboxing easier (https://crbug.com/399473).
91  DCHECK_NE(handle.id_, kInvalidThreadId);
92  const int kNiceSetting = ThreadNiceValue(priority);
93  const PlatformThreadId current_id = PlatformThread::CurrentId();
94  if (setpriority(PRIO_PROCESS,
95                  handle.id_ == current_id ? 0 : handle.id_,
96                  kNiceSetting)) {
97    DVPLOG(1) << "Failed to set nice value of thread (" << handle.id_ << ") to "
98              << kNiceSetting;
99  }
100#endif  //  !defined(OS_NACL)
101}
102
103void InitThreading() {}
104
105void InitOnThread() {}
106
107void TerminateOnThread() {}
108
109size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
110#if !defined(THREAD_SANITIZER)
111  return 0;
112#else
113  // ThreadSanitizer bloats the stack heavily. Evidence has been that the
114  // default stack size isn't enough for some browser tests.
115  return 2 * (1 << 23);  // 2 times 8192K (the default stack size on Linux).
116#endif
117}
118
119}  // namespace base
120