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// Copyright (c) 2006-2008 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 "base/platform_thread.h"
#include <errno.h>
#include <sched.h>
#if defined(OS_MACOSX)
#include <mach/mach.h>
#include <sys/resource.h>
#include <algorithm>
#endif
#if defined(OS_LINUX)
#include <dlfcn.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <unistd.h>
#endif
#if defined(OS_NACL)
#include <sys/nacl_syscalls.h>
#endif
#include "base/logging.h"
#include "base/safe_strerror_posix.h"
#if defined(OS_MACOSX)
namespace base {
void InitThreading();
} // namespace base
#endif
static void* ThreadFunc(void* closure) {
PlatformThread::Delegate* delegate =
static_cast<PlatformThread::Delegate*>(closure);
delegate->ThreadMain();
return NULL;
}
// static
PlatformThreadId PlatformThread::CurrentId() {
// Pthreads doesn't have the concept of a thread ID, so we have to reach down
// into the kernel.
#if defined(OS_MACOSX)
return mach_thread_self();
#elif defined(OS_LINUX)
return syscall(__NR_gettid);
#elif defined(OS_FREEBSD)
// TODO(BSD): find a better thread ID
return reinterpret_cast<int64>(pthread_self());
#elif defined(OS_NACL)
return pthread_self();
#endif
}
// static
void PlatformThread::YieldCurrentThread() {
sched_yield();
}
// static
void PlatformThread::Sleep(int duration_ms) {
struct timespec sleep_time, remaining;
// Contains the portion of duration_ms >= 1 sec.
sleep_time.tv_sec = duration_ms / 1000;
duration_ms -= sleep_time.tv_sec * 1000;
// Contains the portion of duration_ms < 1 sec.
sleep_time.tv_nsec = duration_ms * 1000 * 1000; // nanoseconds.
while (nanosleep(&sleep_time, &remaining) == -1 && errno == EINTR)
sleep_time = remaining;
}
// Linux SetName is currently disabled, as we need to distinguish between
// helper threads (where it's ok to make this call) and the main thread
// (where making this call renames our process, causing tools like killall
// to stop working).
#if 0 && defined(OS_LINUX)
// static
void PlatformThread::SetName(const char* name) {
// http://0pointer.de/blog/projects/name-your-threads.html
// glibc recently added support for pthread_setname_np, but it's not
// commonly available yet. So test for it at runtime.
int (*dynamic_pthread_setname_np)(pthread_t, const char*);
*reinterpret_cast<void**>(&dynamic_pthread_setname_np) =
dlsym(RTLD_DEFAULT, "pthread_setname_np");
if (dynamic_pthread_setname_np) {
// This limit comes from glibc, which gets it from the kernel
// (TASK_COMM_LEN).
const int kMaxNameLength = 15;
std::string shortened_name = std::string(name).substr(0, kMaxNameLength);
int err = dynamic_pthread_setname_np(pthread_self(),
shortened_name.c_str());
if (err < 0)
LOG(ERROR) << "pthread_setname_np: " << safe_strerror(err);
} else {
// Implementing this function without glibc is simple enough. (We
// don't do the name length clipping as above because it will be
// truncated by the callee (see TASK_COMM_LEN above).)
int err = prctl(PR_SET_NAME, name);
if (err < 0)
PLOG(ERROR) << "prctl(PR_SET_NAME)";
}
}
#elif defined(OS_MACOSX)
// Mac is implemented in platform_thread_mac.mm.
#else
// static
void PlatformThread::SetName(const char* name) {
// Leave it unimplemented.
// (This should be relatively simple to implement for the BSDs; I
// just don't have one handy to test the code on.)
}
#endif // defined(OS_LINUX)
namespace {
bool CreateThread(size_t stack_size, bool joinable,
PlatformThread::Delegate* delegate,
PlatformThreadHandle* thread_handle) {
#if defined(OS_MACOSX)
base::InitThreading();
#endif // OS_MACOSX
bool success = false;
pthread_attr_t attributes;
pthread_attr_init(&attributes);
// Pthreads are joinable by default, so only specify the detached attribute if
// the thread should be non-joinable.
if (!joinable) {
pthread_attr_setdetachstate(&attributes, PTHREAD_CREATE_DETACHED);
}
#if defined(OS_MACOSX)
// The Mac OS X default for a pthread stack size is 512kB.
// Libc-594.1.4/pthreads/pthread.c's pthread_attr_init uses
// DEFAULT_STACK_SIZE for this purpose.
//
// 512kB isn't quite generous enough for some deeply recursive threads that
// otherwise request the default stack size by specifying 0. Here, adopt
// glibc's behavior as on Linux, which is to use the current stack size
// limit (ulimit -s) as the default stack size. See
// glibc-2.11.1/nptl/nptl-init.c's __pthread_initialize_minimal_internal. To
// avoid setting the limit below the Mac OS X default or the minimum usable
// stack size, these values are also considered. If any of these values
// can't be determined, or if stack size is unlimited (ulimit -s unlimited),
// stack_size is left at 0 to get the system default.
//
// Mac OS X normally only applies ulimit -s to the main thread stack. On
// contemporary OS X and Linux systems alike, this value is generally 8MB
// or in that neighborhood.
if (stack_size == 0) {
size_t default_stack_size;
struct rlimit stack_rlimit;
if (pthread_attr_getstacksize(&attributes, &default_stack_size) == 0 &&
getrlimit(RLIMIT_STACK, &stack_rlimit) == 0 &&
stack_rlimit.rlim_cur != RLIM_INFINITY) {
stack_size = std::max(std::max(default_stack_size,
static_cast<size_t>(PTHREAD_STACK_MIN)),
static_cast<size_t>(stack_rlimit.rlim_cur));
}
}
#endif // OS_MACOSX
if (stack_size > 0)
pthread_attr_setstacksize(&attributes, stack_size);
success = !pthread_create(thread_handle, &attributes, ThreadFunc, delegate);
pthread_attr_destroy(&attributes);
return success;
}
} // anonymous namespace
// static
bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
PlatformThreadHandle* thread_handle) {
return CreateThread(stack_size, true /* joinable thread */,
delegate, thread_handle);
}
// static
bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
PlatformThreadHandle unused;
bool result = CreateThread(stack_size, false /* non-joinable thread */,
delegate, &unused);
return result;
}
// static
void PlatformThread::Join(PlatformThreadHandle thread_handle) {
pthread_join(thread_handle, NULL);
}
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