/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include "uv.h"

#include "internal.h"

#include <pthread.h>

#include <assert.h>

#include <errno.h>

#include <sys/time.h>

#include <sys/resource.h>  /* getrlimit() */

#include <unistd.h>  /* getpagesize() */

#include <limits.h>

#ifdef __MVS__

#include <sys/ipc.h>

#include <sys/sem.h>

#endif

#ifdef __GLIBC__

#include <gnu/libc-version.h>  /* gnu_get_libc_version() */

#endif

#undef NANOSEC

#define NANOSEC ((uint64_t) 1e9)

#if defined(UV__PTHREAD_BARRIER_FALLBACK)

/* TODO: support barrier_attr */

int pthread_barrier_init(pthread_barrier_t* barrier,

                         const void* barrier_attr,

                         unsigned count) {

  int rc;

  _uv_barrier* b;

  if (barrier == NULL || count == 0)

    return EINVAL;

  if (barrier_attr != NULL)

    return ENOTSUP;

  b = uv__malloc(sizeof(*b));

  if (b == NULL)

    return ENOMEM;

  b->in = 0;

  b->out = 0;

  b->threshold = count;

  if ((rc = pthread_mutex_init(&b->mutex, NULL)) != 0)

    goto error2;

  if ((rc = pthread_cond_init(&b->cond, NULL)) != 0)

    goto error;

  barrier->b = b;

  return 0;

error:

  pthread_mutex_destroy(&b->mutex);

error2:

  uv__free(b);

  return rc;

}

int pthread_barrier_wait(pthread_barrier_t* barrier) {

  int rc;

  _uv_barrier* b;

  if (barrier == NULL || barrier->b == NULL)

    return EINVAL;

  b = barrier->b;

  /* Lock the mutex*/

  if ((rc = pthread_mutex_lock(&b->mutex)) != 0)

    return rc;

  /* Increment the count. If this is the first thread to reach the threshold,

     wake up waiters, unlock the mutex, then return

     PTHREAD_BARRIER_SERIAL_THREAD. */

  if (++b->in == b->threshold) {

    b->in = 0;

    b->out = b->threshold - 1;

    rc = pthread_cond_signal(&b->cond);

    assert(rc == 0);

    pthread_mutex_unlock(&b->mutex);

    return PTHREAD_BARRIER_SERIAL_THREAD;

  }

  /* Otherwise, wait for other threads until in is set to 0,

     then return 0 to indicate this is not the first thread. */

  do {

    if ((rc = pthread_cond_wait(&b->cond, &b->mutex)) != 0)

      break;

  } while (b->in != 0);

  /* mark thread exit */

  b->out--;

  pthread_cond_signal(&b->cond);

  pthread_mutex_unlock(&b->mutex);

  return rc;

}

int pthread_barrier_destroy(pthread_barrier_t* barrier) {

  int rc;

  _uv_barrier* b;

  if (barrier == NULL || barrier->b == NULL)

    return EINVAL;

  b = barrier->b;

  if ((rc = pthread_mutex_lock(&b->mutex)) != 0)

    return rc;

  if (b->in > 0 || b->out > 0)

    rc = EBUSY;

  pthread_mutex_unlock(&b->mutex);

  if (rc)

    return rc;

  pthread_cond_destroy(&b->cond);

  pthread_mutex_destroy(&b->mutex);

  uv__free(barrier->b);

  barrier->b = NULL;

  return 0;

}

#endif

/* On MacOS, threads other than the main thread are created with a reduced

 * stack size by default.  Adjust to RLIMIT_STACK aligned to the page size.

 *

 * On Linux, threads created by musl have a much smaller stack than threads

 * created by glibc (80 vs. 2048 or 4096 kB.)  Follow glibc for consistency.

 */

static size_t thread_stack_size(void) {

#if defined(__APPLE__) || defined(__linux__)

  struct rlimit lim;

  if (getrlimit(RLIMIT_STACK, &lim))

    abort();

  if (lim.rlim_cur != RLIM_INFINITY) {

    /* pthread_attr_setstacksize() expects page-aligned values. */

    lim.rlim_cur -= lim.rlim_cur % (rlim_t) getpagesize();

    if (lim.rlim_cur >= PTHREAD_STACK_MIN)

      return lim.rlim_cur;

  }

#endif

#if !defined(__linux__)

  return 0;

#elif defined(__PPC__) || defined(__ppc__) || defined(__powerpc__)

  return 4 << 20;  /* glibc default. */

#else

  return 2 << 20;  /* glibc default. */

#endif

}

int uv_thread_create(uv_thread_t *tid, void (*entry)(void *arg), void *arg) {

  int err;

  size_t stack_size;

  pthread_attr_t* attr;

  pthread_attr_t attr_storage;

  attr = NULL;

  stack_size = thread_stack_size();

  if (stack_size > 0) {

    attr = &attr_storage;

    if (pthread_attr_init(attr))

      abort();

    if (pthread_attr_setstacksize(attr, stack_size))

      abort();

  }

  err = pthread_create(tid, attr, (void*(*)(void*)) entry, arg);

  if (attr != NULL)

    pthread_attr_destroy(attr);

  return UV__ERR(err);

}

uv_thread_t uv_thread_self(void) {

  return pthread_self();

}

int uv_thread_join(uv_thread_t *tid) {

  return UV__ERR(pthread_join(*tid, NULL));

}

int uv_thread_equal(const uv_thread_t* t1, const uv_thread_t* t2) {

  return pthread_equal(*t1, *t2);

}

int uv_mutex_init(uv_mutex_t* mutex) {

#if defined(NDEBUG) || !defined(PTHREAD_MUTEX_ERRORCHECK)

  return UV__ERR(pthread_mutex_init(mutex, NULL));

#else

  pthread_mutexattr_t attr;

  int err;

  if (pthread_mutexattr_init(&attr))

    abort();

  if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK))

    abort();

  err = pthread_mutex_init(mutex, &attr);

  if (pthread_mutexattr_destroy(&attr))

    abort();

  return UV__ERR(err);

#endif

}

int uv_mutex_init_recursive(uv_mutex_t* mutex) {

  pthread_mutexattr_t attr;

  int err;

  if (pthread_mutexattr_init(&attr))

    abort();

  if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE))

    abort();

  err = pthread_mutex_init(mutex, &attr);

  if (pthread_mutexattr_destroy(&attr))

    abort();

  return UV__ERR(err);

}

void uv_mutex_destroy(uv_mutex_t* mutex) {

  if (pthread_mutex_destroy(mutex))

    abort();

}

void uv_mutex_lock(uv_mutex_t* mutex) {

  if (pthread_mutex_lock(mutex))

    abort();

}

int uv_mutex_trylock(uv_mutex_t* mutex) {

  int err;

  err = pthread_mutex_trylock(mutex);

  if (err) {

    if (err != EBUSY && err != EAGAIN)

      abort();

    return UV_EBUSY;

  }

  return 0;

}

void uv_mutex_unlock(uv_mutex_t* mutex) {

  if (pthread_mutex_unlock(mutex))

    abort();

}

int uv_rwlock_init(uv_rwlock_t* rwlock) {

  return UV__ERR(pthread_rwlock_init(rwlock, NULL));

}

void uv_rwlock_destroy(uv_rwlock_t* rwlock) {

  if (pthread_rwlock_destroy(rwlock))

    abort();

}

void uv_rwlock_rdlock(uv_rwlock_t* rwlock) {

  if (pthread_rwlock_rdlock(rwlock))

    abort();

}

int uv_rwlock_tryrdlock(uv_rwlock_t* rwlock) {

  int err;

  err = pthread_rwlock_tryrdlock(rwlock);

  if (err) {

    if (err != EBUSY && err != EAGAIN)

      abort();

    return UV_EBUSY;

  }

  return 0;

}

void uv_rwlock_rdunlock(uv_rwlock_t* rwlock) {

  if (pthread_rwlock_unlock(rwlock))

    abort();

}

void uv_rwlock_wrlock(uv_rwlock_t* rwlock) {

  if (pthread_rwlock_wrlock(rwlock))

    abort();

}

int uv_rwlock_trywrlock(uv_rwlock_t* rwlock) {

  int err;

  err = pthread_rwlock_trywrlock(rwlock);

  if (err) {

    if (err != EBUSY && err != EAGAIN)

      abort();

    return UV_EBUSY;

  }

  return 0;

}

void uv_rwlock_wrunlock(uv_rwlock_t* rwlock) {

  if (pthread_rwlock_unlock(rwlock))

    abort();

}

void uv_once(uv_once_t* guard, void (*callback)(void)) {

  if (pthread_once(guard, callback))

    abort();

}

#if defined(__APPLE__) && defined(__MACH__)

int uv_sem_init(uv_sem_t* sem, unsigned int value) {

  kern_return_t err;

  err = semaphore_create(mach_task_self(), sem, SYNC_POLICY_FIFO, value);

  if (err == KERN_SUCCESS)

    return 0;

  if (err == KERN_INVALID_ARGUMENT)

    return UV_EINVAL;

  if (err == KERN_RESOURCE_SHORTAGE)

    return UV_ENOMEM;

  abort();

  return UV_EINVAL;  /* Satisfy the compiler. */

}

void uv_sem_destroy(uv_sem_t* sem) {

  if (semaphore_destroy(mach_task_self(), *sem))

    abort();

}

void uv_sem_post(uv_sem_t* sem) {

  if (semaphore_signal(*sem))

    abort();

}

void uv_sem_wait(uv_sem_t* sem) {

  int r;

  do

    r = semaphore_wait(*sem);

  while (r == KERN_ABORTED);

  if (r != KERN_SUCCESS)

    abort();

}

int uv_sem_trywait(uv_sem_t* sem) {

  mach_timespec_t interval;

  kern_return_t err;

  interval.tv_sec = 0;

  interval.tv_nsec = 0;

  err = semaphore_timedwait(*sem, interval);

  if (err == KERN_SUCCESS)

    return 0;

  if (err == KERN_OPERATION_TIMED_OUT)

    return UV_EAGAIN;

  abort();

  return UV_EINVAL;  /* Satisfy the compiler. */

}

#else /* !(defined(__APPLE__) && defined(__MACH__)) */

#ifdef __GLIBC__

/* Hack around https://sourceware.org/bugzilla/show_bug.cgi?id=12674

 * by providing a custom implementation for glibc < 2.21 in terms of other

 * concurrency primitives.

 * Refs: https://github.com/nodejs/node/issues/19903 */

/* To preserve ABI compatibility, we treat the uv_sem_t as storage for

 * a pointer to the actual struct we're using underneath. */

static uv_once_t glibc_version_check_once = UV_ONCE_INIT;

static int platform_needs_custom_semaphore = 0;

static void glibc_version_check(void) {

  const char* version = gnu_get_libc_version();

  platform_needs_custom_semaphore =

      version[0] == '2' && version[1] == '.' &&

      atoi(version + 2) < 21;

}

#elif defined(__MVS__)

#define platform_needs_custom_semaphore 1

#else /* !defined(__GLIBC__) && !defined(__MVS__) */

#define platform_needs_custom_semaphore 0

#endif

typedef struct uv_semaphore_s {

  uv_mutex_t mutex;

  uv_cond_t cond;

  unsigned int value;

} uv_semaphore_t;

#if defined(__GLIBC__) || platform_needs_custom_semaphore

STATIC_ASSERT(sizeof(uv_sem_t) >= sizeof(uv_semaphore_t*));

#endif

static int uv__custom_sem_init(uv_sem_t* sem_, unsigned int value) {

  int err;

  uv_semaphore_t* sem;

  sem = uv__malloc(sizeof(*sem));

  if (sem == NULL)

    return UV_ENOMEM;

  if ((err = uv_mutex_init(&sem->mutex)) != 0) {

    uv__free(sem);

    return err;

  }

  if ((err = uv_cond_init(&sem->cond)) != 0) {

    uv_mutex_destroy(&sem->mutex);

    uv__free(sem);

    return err;

  }

  sem->value = value;

  *(uv_semaphore_t**)sem_ = sem;

  return 0;

}

static void uv__custom_sem_destroy(uv_sem_t* sem_) {

  uv_semaphore_t* sem;

  sem = *(uv_semaphore_t**)sem_;

  uv_cond_destroy(&sem->cond);

  uv_mutex_destroy(&sem->mutex);

  uv__free(sem);

}

static void uv__custom_sem_post(uv_sem_t* sem_) {

  uv_semaphore_t* sem;

  sem = *(uv_semaphore_t**)sem_;

  uv_mutex_lock(&sem->mutex);

  sem->value++;

  if (sem->value == 1)

    uv_cond_signal(&sem->cond);

  uv_mutex_unlock(&sem->mutex);

}

static void uv__custom_sem_wait(uv_sem_t* sem_) {

  uv_semaphore_t* sem;

  sem = *(uv_semaphore_t**)sem_;

  uv_mutex_lock(&sem->mutex);

  while (sem->value == 0)

    uv_cond_wait(&sem->cond, &sem->mutex);

  sem->value--;

  uv_mutex_unlock(&sem->mutex);

}

static int uv__custom_sem_trywait(uv_sem_t* sem_) {

  uv_semaphore_t* sem;

  sem = *(uv_semaphore_t**)sem_;

  if (uv_mutex_trylock(&sem->mutex) != 0)

    return UV_EAGAIN;

  if (sem->value == 0) {

    uv_mutex_unlock(&sem->mutex);

    return UV_EAGAIN;

  }

  sem->value--;

  uv_mutex_unlock(&sem->mutex);

  return 0;

}

static int uv__sem_init(uv_sem_t* sem, unsigned int value) {

  if (sem_init(sem, 0, value))

    return UV__ERR(errno);

  return 0;

}

static void uv__sem_destroy(uv_sem_t* sem) {

  if (sem_destroy(sem))

    abort();

}

static void uv__sem_post(uv_sem_t* sem) {

  if (sem_post(sem))

    abort();

}

static void uv__sem_wait(uv_sem_t* sem) {

  int r;

  do

    r = sem_wait(sem);

  while (r == -1 && errno == EINTR);

  if (r)

    abort();

}

static int uv__sem_trywait(uv_sem_t* sem) {

  int r;

  do

    r = sem_trywait(sem);

  while (r == -1 && errno == EINTR);

  if (r) {

    if (errno == EAGAIN)

      return UV_EAGAIN;

    abort();

  }

  return 0;

}

int uv_sem_init(uv_sem_t* sem, unsigned int value) {

#ifdef __GLIBC__

  uv_once(&glibc_version_check_once, glibc_version_check);

#endif

  if (platform_needs_custom_semaphore)

    return uv__custom_sem_init(sem, value);

  else

    return uv__sem_init(sem, value);

}

void uv_sem_destroy(uv_sem_t* sem) {

  if (platform_needs_custom_semaphore)

    uv__custom_sem_destroy(sem);

  else

    uv__sem_destroy(sem);

}

void uv_sem_post(uv_sem_t* sem) {

  if (platform_needs_custom_semaphore)

    uv__custom_sem_post(sem);

  else

    uv__sem_post(sem);

}

void uv_sem_wait(uv_sem_t* sem) {

  if (platform_needs_custom_semaphore)

    uv__custom_sem_wait(sem);

  else

    uv__sem_wait(sem);

}

int uv_sem_trywait(uv_sem_t* sem) {

  if (platform_needs_custom_semaphore)

    return uv__custom_sem_trywait(sem);

  else

    return uv__sem_trywait(sem);

}

#endif /* defined(__APPLE__) && defined(__MACH__) */

#if defined(__APPLE__) && defined(__MACH__) || defined(__MVS__)

int uv_cond_init(uv_cond_t* cond) {

  return UV__ERR(pthread_cond_init(cond, NULL));

}

#else /* !(defined(__APPLE__) && defined(__MACH__)) */

int uv_cond_init(uv_cond_t* cond) {

  pthread_condattr_t attr;

  int err;

  err = pthread_condattr_init(&attr);

  if (err)

    return UV__ERR(err);

#if !(defined(__ANDROID_API__) && __ANDROID_API__ < 21)

  err = pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);

  if (err)

    goto error2;

#endif

  err = pthread_cond_init(cond, &attr);

  if (err)

    goto error2;

  err = pthread_condattr_destroy(&attr);

  if (err)

    goto error;

  return 0;

error:

  pthread_cond_destroy(cond);

error2:

  pthread_condattr_destroy(&attr);

  return UV__ERR(err);

}

#endif /* defined(__APPLE__) && defined(__MACH__) */

void uv_cond_destroy(uv_cond_t* cond) {

#if defined(__APPLE__) && defined(__MACH__)

  /* It has been reported that destroying condition variables that have been

   * signalled but not waited on can sometimes result in application crashes.

   * See https://codereview.chromium.org/1323293005.

   */

  pthread_mutex_t mutex;

  struct timespec ts;

  int err;

  if (pthread_mutex_init(&mutex, NULL))

    abort();

  if (pthread_mutex_lock(&mutex))

    abort();

  ts.tv_sec = 0;

  ts.tv_nsec = 1;

  err = pthread_cond_timedwait_relative_np(cond, &mutex, &ts);

  if (err != 0 && err != ETIMEDOUT)

    abort();

  if (pthread_mutex_unlock(&mutex))

    abort();

  if (pthread_mutex_destroy(&mutex))

    abort();

#endif /* defined(__APPLE__) && defined(__MACH__) */

  if (pthread_cond_destroy(cond))

    abort();

}

void uv_cond_signal(uv_cond_t* cond) {

  if (pthread_cond_signal(cond))

    abort();

}

void uv_cond_broadcast(uv_cond_t* cond) {

  if (pthread_cond_broadcast(cond))

    abort();

}

void uv_cond_wait(uv_cond_t* cond, uv_mutex_t* mutex) {

  if (pthread_cond_wait(cond, mutex))

    abort();

}

int uv_cond_timedwait(uv_cond_t* cond, uv_mutex_t* mutex, uint64_t timeout) {

  int r;

  struct timespec ts;

#if defined(__MVS__)

  struct timeval tv;

#endif

#if defined(__APPLE__) && defined(__MACH__)

  ts.tv_sec = timeout / NANOSEC;

  ts.tv_nsec = timeout % NANOSEC;

  r = pthread_cond_timedwait_relative_np(cond, mutex, &ts);

#else

#if defined(__MVS__)

  if (gettimeofday(&tv, NULL))

    abort();

  timeout += tv.tv_sec * NANOSEC + tv.tv_usec * 1e3;

#else

  timeout += uv__hrtime(UV_CLOCK_PRECISE);

#endif

  ts.tv_sec = timeout / NANOSEC;

  ts.tv_nsec = timeout % NANOSEC;

#if defined(__ANDROID_API__) && __ANDROID_API__ < 21

  /*

   * The bionic pthread implementation doesn't support CLOCK_MONOTONIC,

   * but has this alternative function instead.

   */

  r = pthread_cond_timedwait_monotonic_np(cond, mutex, &ts);

#else

  r = pthread_cond_timedwait(cond, mutex, &ts);

#endif /* __ANDROID_API__ */

#endif

  if (r == 0)

    return 0;

  if (r == ETIMEDOUT)

    return UV_ETIMEDOUT;

  abort();

  return UV_EINVAL;  /* Satisfy the compiler. */

}

int uv_barrier_init(uv_barrier_t* barrier, unsigned int count) {

  return UV__ERR(pthread_barrier_init(barrier, NULL, count));

}

void uv_barrier_destroy(uv_barrier_t* barrier) {

  if (pthread_barrier_destroy(barrier))

    abort();

}

int uv_barrier_wait(uv_barrier_t* barrier) {

  int r = pthread_barrier_wait(barrier);

  if (r && r != PTHREAD_BARRIER_SERIAL_THREAD)

    abort();

  return r == PTHREAD_BARRIER_SERIAL_THREAD;

}

int uv_key_create(uv_key_t* key) {

  return UV__ERR(pthread_key_create(key, NULL));

}

void uv_key_delete(uv_key_t* key) {

  if (pthread_key_delete(*key))

    abort();

}

void* uv_key_get(uv_key_t* key) {

  return pthread_getspecific(*key);

}

void uv_key_set(uv_key_t* key, void* value) {

  if (pthread_setspecific(*key, value))

    abort();

}