// 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 "butil/threading/platform_thread.h"

#include <errno.h>

#include <sched.h>

#include "butil/lazy_instance.h"

#include "butil/logging.h"

#include "butil/memory/scoped_ptr.h"

#include "butil/safe_strerror_posix.h"

#include "butil/threading/thread_id_name_manager.h"

#include "butil/threading/thread_restrictions.h"

#if !defined(OS_NACL)

#include <sys/prctl.h>

#include <sys/resource.h>

#include <sys/syscall.h>

#include <sys/time.h>

#include <unistd.h>

#endif

namespace butil {

namespace {

int ThreadNiceValue(ThreadPriority priority) {

  switch (priority) {

    case kThreadPriority_RealtimeAudio:

      return -10;

    case kThreadPriority_Background:

      return 10;

    case kThreadPriority_Normal:

      return 0;

    case kThreadPriority_Display:

      return -6;

    default:

      NOTREACHED() << "Unknown priority.";

      return 0;

  }

}

}  // namespace

// NOTE(gejun): PR_SET_NAME was added in 2.6.9, should be working on most of

// our machines, but missing from our linux headers.

#if !defined(PR_SET_NAME)

#define PR_SET_NAME 15

#endif

// static

void PlatformThread::SetName(const char* name) {

  ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);

#if !defined(OS_NACL)

  // On linux we can get the thread names to show up in the debugger by setting

  // the process name for the LWP.  We don't want to do this for the main

  // thread because that would rename the process, causing tools like killall

  // to stop working.

  if (PlatformThread::CurrentId() == getpid())

    return;

  // http://0pointer.de/blog/projects/name-your-threads.html

  // Set the name for the LWP (which gets truncated to 15 characters).

  // Note that glibc also has a 'pthread_setname_np' api, but it may not be

  // available everywhere and it's only benefit over using prctl directly is

  // that it can set the name of threads other than the current thread.

  int err = prctl(PR_SET_NAME, name);

  // We expect EPERM failures in sandboxed processes, just ignore those.

  if (err < 0 && errno != EPERM)

    DPLOG(ERROR) << "prctl(PR_SET_NAME)";

#endif  //  !defined(OS_NACL)

}

// static

void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,

                                       ThreadPriority priority) {

#if !defined(OS_NACL)

  if (priority == kThreadPriority_RealtimeAudio) {

    const struct sched_param kRealTimePrio = { 8 };

    if (pthread_setschedparam(pthread_self(), SCHED_RR, &kRealTimePrio) == 0) {

      // Got real time priority, no need to set nice level.

      return;

    }

  }

  // setpriority(2) will set a thread's priority if it is passed a tid as

  // the 'process identifier', not affecting the rest of the threads in the

  // process. Setting this priority will only succeed if the user has been

  // granted permission to adjust nice values on the system.

  DCHECK_NE(handle.id_, kInvalidThreadId);

  const int kNiceSetting = ThreadNiceValue(priority);

  if (setpriority(PRIO_PROCESS, handle.id_, kNiceSetting)) {

    DVPLOG(1) << "Failed to set nice value of thread ("

              << handle.id_ << ") to " << kNiceSetting;

  }

#endif  //  !defined(OS_NACL)

}

void InitThreading() {}

void InitOnThread() {}

void TerminateOnThread() {}

size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {

#if !defined(THREAD_SANITIZER) && !defined(MEMORY_SANITIZER)

  return 0;

#else

  // ThreadSanitizer bloats the stack heavily. Evidence has been that the

  // default stack size isn't enough for some browser tests.

  // MemorySanitizer needs this as a temporary fix for http://crbug.com/353687

  return 2 * (1 << 23);  // 2 times 8192K (the default stack size on Linux).

#endif

}

}  // namespace butil