/* Copyright (C) 2002-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <assert.h>

#include <errno.h>

#include <time.h>

#include <sys/param.h>

#include <sys/time.h>

#include "pthreadP.h"

#include <atomic.h>

#include <lowlevellock.h>

#include <not-cancel.h>

#include <stap-probe.h>

#ifndef lll_timedlock_elision

#define lll_timedlock_elision(a,dummy,b,c) lll_timedlock(a, b, c)

#endif

#ifndef lll_trylock_elision

#define lll_trylock_elision(a,t) lll_trylock(a)

#endif

#ifndef FORCE_ELISION

#define FORCE_ELISION(m, s)

#endif

int

__pthread_mutex_timedlock (pthread_mutex_t *mutex,

			   const struct timespec *abstime)

{

  int oldval;

  pid_t id = THREAD_GETMEM (THREAD_SELF, tid);

  int result = 0;

  LIBC_PROBE (mutex_timedlock_entry, 2, mutex, abstime);

  /* We must not check ABSTIME here.  If the thread does not block

     abstime must not be checked for a valid value.  */

  /* See concurrency notes regarding mutex type which is loaded from __kind

     in struct __pthread_mutex_s in sysdeps/nptl/bits/thread-shared-types.h.  */

  switch (__builtin_expect (PTHREAD_MUTEX_TYPE_ELISION (mutex),

			    PTHREAD_MUTEX_TIMED_NP))

    {

      /* Recursive mutex.  */

    case PTHREAD_MUTEX_RECURSIVE_NP|PTHREAD_MUTEX_ELISION_NP:

    case PTHREAD_MUTEX_RECURSIVE_NP:

      /* Check whether we already hold the mutex.  */

      if (mutex->__data.__owner == id)

	{

	  /* Just bump the counter.  */

	  if (__glibc_unlikely (mutex->__data.__count + 1 == 0))

	    /* Overflow of the counter.  */

	    return EAGAIN;

	  ++mutex->__data.__count;

	  goto out;

	}

      /* We have to get the mutex.  */

      result = lll_timedlock (mutex->__data.__lock, abstime,

			      PTHREAD_MUTEX_PSHARED (mutex));

      if (result != 0)

	goto out;

      /* Only locked once so far.  */

      mutex->__data.__count = 1;

      break;

      /* Error checking mutex.  */

    case PTHREAD_MUTEX_ERRORCHECK_NP:

      /* Check whether we already hold the mutex.  */

      if (__glibc_unlikely (mutex->__data.__owner == id))

	return EDEADLK;

      /* Don't do lock elision on an error checking mutex.  */

      goto simple;

    case PTHREAD_MUTEX_TIMED_NP:

      FORCE_ELISION (mutex, goto elision);

    simple:

      /* Normal mutex.  */

      result = lll_timedlock (mutex->__data.__lock, abstime,

			      PTHREAD_MUTEX_PSHARED (mutex));

      break;

    case PTHREAD_MUTEX_TIMED_ELISION_NP:

    elision: __attribute__((unused))

      /* Don't record ownership */

      return lll_timedlock_elision (mutex->__data.__lock,

				    mutex->__data.__spins,

				    abstime,

				    PTHREAD_MUTEX_PSHARED (mutex));

    case PTHREAD_MUTEX_ADAPTIVE_NP:

      if (! __is_smp)

	goto simple;

      if (lll_trylock (mutex->__data.__lock) != 0)

	{

	  int cnt = 0;

	  int max_cnt = MIN (MAX_ADAPTIVE_COUNT,

			     mutex->__data.__spins * 2 + 10);

	  do

	    {

	      if (cnt++ >= max_cnt)

		{

		  result = lll_timedlock (mutex->__data.__lock, abstime,

					  PTHREAD_MUTEX_PSHARED (mutex));

		  break;

		}

	      atomic_spin_nop ();

	    }

	  while (lll_trylock (mutex->__data.__lock) != 0);

	  mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8;

	}

      break;

    case PTHREAD_MUTEX_ROBUST_RECURSIVE_NP:

    case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP:

    case PTHREAD_MUTEX_ROBUST_NORMAL_NP:

    case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP:

      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,

		     &mutex->__data.__list.__next);

      /* We need to set op_pending before starting the operation.  Also

	 see comments at ENQUEUE_MUTEX.  */

      __asm ("" ::: "memory");

      oldval = mutex->__data.__lock;

      /* This is set to FUTEX_WAITERS iff we might have shared the

	 FUTEX_WAITERS flag with other threads, and therefore need to keep it

	 set to avoid lost wake-ups.  We have the same requirement in the

	 simple mutex algorithm.  */

      unsigned int assume_other_futex_waiters = 0;

      while (1)

	{

	  /* Try to acquire the lock through a CAS from 0 (not acquired) to

	     our TID | assume_other_futex_waiters.  */

	  if (__glibc_likely (oldval == 0))

	    {

	      oldval

	        = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,

	            id | assume_other_futex_waiters, 0);

	      if (__glibc_likely (oldval == 0))

		break;

	    }

	  if ((oldval & FUTEX_OWNER_DIED) != 0)

	    {

	      /* The previous owner died.  Try locking the mutex.  */

	      int newval = id | (oldval & FUTEX_WAITERS)

		  | assume_other_futex_waiters;

	      newval

		= atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,

						       newval, oldval);

	      if (newval != oldval)

		{

		  oldval = newval;

		  continue;

		}

	      /* We got the mutex.  */

	      mutex->__data.__count = 1;

	      /* But it is inconsistent unless marked otherwise.  */

	      mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT;

	      /* We must not enqueue the mutex before we have acquired it.

		 Also see comments at ENQUEUE_MUTEX.  */

	      __asm ("" ::: "memory");

	      ENQUEUE_MUTEX (mutex);

	      /* We need to clear op_pending after we enqueue the mutex.  */

	      __asm ("" ::: "memory");

	      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

	      /* Note that we deliberately exit here.  If we fall

		 through to the end of the function __nusers would be

		 incremented which is not correct because the old

		 owner has to be discounted.  */

	      return EOWNERDEAD;

	    }

	  /* Check whether we already hold the mutex.  */

	  if (__glibc_unlikely ((oldval & FUTEX_TID_MASK) == id))

	    {

	      int kind = PTHREAD_MUTEX_TYPE (mutex);

	      if (kind == PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP)

		{

		  /* We do not need to ensure ordering wrt another memory

		     access.  Also see comments at ENQUEUE_MUTEX. */

		  THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,

				 NULL);

		  return EDEADLK;

		}

	      if (kind == PTHREAD_MUTEX_ROBUST_RECURSIVE_NP)

		{

		  /* We do not need to ensure ordering wrt another memory

		     access.  */

		  THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,

				 NULL);

		  /* Just bump the counter.  */

		  if (__glibc_unlikely (mutex->__data.__count + 1 == 0))

		    /* Overflow of the counter.  */

		    return EAGAIN;

		  ++mutex->__data.__count;

		  LIBC_PROBE (mutex_timedlock_acquired, 1, mutex);

		  return 0;

		}

	    }

	  /* We are about to block; check whether the timeout is invalid.  */

	  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)

	    return EINVAL;

	  /* Work around the fact that the kernel rejects negative timeout

	     values despite them being valid.  */

	  if (__glibc_unlikely (abstime->tv_sec < 0))

	    return ETIMEDOUT;

#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \

     || !defined lll_futex_timed_wait_bitset)

	  struct timeval tv;

	  struct timespec rt;

	  /* Get the current time.  */

	  (void) __gettimeofday (&tv, NULL);

	  /* Compute relative timeout.  */

	  rt.tv_sec = abstime->tv_sec - tv.tv_sec;

	  rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;

	  if (rt.tv_nsec < 0)

	    {

	      rt.tv_nsec += 1000000000;

	      --rt.tv_sec;

	    }

	  /* Already timed out?  */

	  if (rt.tv_sec < 0)

	    return ETIMEDOUT;

#endif

	  /* We cannot acquire the mutex nor has its owner died.  Thus, try

	     to block using futexes.  Set FUTEX_WAITERS if necessary so that

	     other threads are aware that there are potentially threads

	     blocked on the futex.  Restart if oldval changed in the

	     meantime.  */

	  if ((oldval & FUTEX_WAITERS) == 0)

	    {

	      if (atomic_compare_and_exchange_bool_acq (&mutex->__data.__lock,

							oldval | FUTEX_WAITERS,

							oldval)

		  != 0)

		{

		  oldval = mutex->__data.__lock;

		  continue;

		}

	      oldval |= FUTEX_WAITERS;

	    }

	  /* It is now possible that we share the FUTEX_WAITERS flag with

	     another thread; therefore, update assume_other_futex_waiters so

	     that we do not forget about this when handling other cases

	     above and thus do not cause lost wake-ups.  */

	  assume_other_futex_waiters |= FUTEX_WAITERS;

	  /* Block using the futex.  */

#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \

     || !defined lll_futex_timed_wait_bitset)

	  lll_futex_timed_wait (&mutex->__data.__lock, oldval,

				&rt, PTHREAD_ROBUST_MUTEX_PSHARED (mutex));

#else

	  int err = lll_futex_timed_wait_bitset (&mutex->__data.__lock,

	      oldval, abstime, FUTEX_CLOCK_REALTIME,

	      PTHREAD_ROBUST_MUTEX_PSHARED (mutex));

	  /* The futex call timed out.  */

	  if (err == -ETIMEDOUT)

	    return -err;

#endif

	  /* Reload current lock value.  */

	  oldval = mutex->__data.__lock;

	}

      /* We have acquired the mutex; check if it is still consistent.  */

      if (__builtin_expect (mutex->__data.__owner

			    == PTHREAD_MUTEX_NOTRECOVERABLE, 0))

	{

	  /* This mutex is now not recoverable.  */

	  mutex->__data.__count = 0;

	  int private = PTHREAD_ROBUST_MUTEX_PSHARED (mutex);

	  lll_unlock (mutex->__data.__lock, private);

	  /* FIXME This violates the mutex destruction requirements.  See

	     __pthread_mutex_unlock_full.  */

	  THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

	  return ENOTRECOVERABLE;

	}

      mutex->__data.__count = 1;

      /* We must not enqueue the mutex before we have acquired it.

	 Also see comments at ENQUEUE_MUTEX.  */

      __asm ("" ::: "memory");

      ENQUEUE_MUTEX (mutex);

      /* We need to clear op_pending after we enqueue the mutex.  */

      __asm ("" ::: "memory");

      THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

      break;

    /* The PI support requires the Linux futex system call.  If that's not

       available, pthread_mutex_init should never have allowed the type to

       be set.  So it will get the default case for an invalid type.  */

#ifdef __NR_futex

    case PTHREAD_MUTEX_PI_RECURSIVE_NP:

    case PTHREAD_MUTEX_PI_ERRORCHECK_NP:

    case PTHREAD_MUTEX_PI_NORMAL_NP:

    case PTHREAD_MUTEX_PI_ADAPTIVE_NP:

    case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP:

    case PTHREAD_MUTEX_PI_ROBUST_ERRORCHECK_NP:

    case PTHREAD_MUTEX_PI_ROBUST_NORMAL_NP:

    case PTHREAD_MUTEX_PI_ROBUST_ADAPTIVE_NP:

      {

	int kind, robust;

	{

	  /* See concurrency notes regarding __kind in struct __pthread_mutex_s

	     in sysdeps/nptl/bits/thread-shared-types.h.  */

	  int mutex_kind = atomic_load_relaxed (&(mutex->__data.__kind));

	  kind = mutex_kind & PTHREAD_MUTEX_KIND_MASK_NP;

	  robust = mutex_kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP;

	}

	if (robust)

	  {

	    /* Note: robust PI futexes are signaled by setting bit 0.  */

	    THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,

			   (void *) (((uintptr_t) &mutex->__data.__list.__next)

				     | 1));

	    /* We need to set op_pending before starting the operation.  Also

	       see comments at ENQUEUE_MUTEX.  */

	    __asm ("" ::: "memory");

	  }

	oldval = mutex->__data.__lock;

	/* Check whether we already hold the mutex.  */

	if (__glibc_unlikely ((oldval & FUTEX_TID_MASK) == id))

	  {

	    if (kind == PTHREAD_MUTEX_ERRORCHECK_NP)

	      {

		/* We do not need to ensure ordering wrt another memory

		   access.  */

		THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

		return EDEADLK;

	      }

	    if (kind == PTHREAD_MUTEX_RECURSIVE_NP)

	      {

		/* We do not need to ensure ordering wrt another memory

		   access.  */

		THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

		/* Just bump the counter.  */

		if (__glibc_unlikely (mutex->__data.__count + 1 == 0))

		  /* Overflow of the counter.  */

		  return EAGAIN;

		++mutex->__data.__count;

		LIBC_PROBE (mutex_timedlock_acquired, 1, mutex);

		return 0;

	      }

	  }

	oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,

						      id, 0);

	if (oldval != 0)

	  {

	    /* The mutex is locked.  The kernel will now take care of

	       everything.  The timeout value must be a relative value.

	       Convert it.  */

	    int private = (robust

			   ? PTHREAD_ROBUST_MUTEX_PSHARED (mutex)

			   : PTHREAD_MUTEX_PSHARED (mutex));

	    INTERNAL_SYSCALL_DECL (__err);

	    int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock,

				      __lll_private_flag (FUTEX_LOCK_PI,

							  private), 1,

				      abstime);

	    if (INTERNAL_SYSCALL_ERROR_P (e, __err))

	      {

		if (INTERNAL_SYSCALL_ERRNO (e, __err) == ETIMEDOUT)

		  return ETIMEDOUT;

		if (INTERNAL_SYSCALL_ERRNO (e, __err) == ESRCH

		    || INTERNAL_SYSCALL_ERRNO (e, __err) == EDEADLK)

		  {

		    assert (INTERNAL_SYSCALL_ERRNO (e, __err) != EDEADLK

			    || (kind != PTHREAD_MUTEX_ERRORCHECK_NP

				&& kind != PTHREAD_MUTEX_RECURSIVE_NP));

		    /* ESRCH can happen only for non-robust PI mutexes where

		       the owner of the lock died.  */

		    assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH

			    || !robust);

		    /* Delay the thread until the timeout is reached.

		       Then return ETIMEDOUT.  */

		    struct timespec reltime;

		    struct timespec now;

		    INTERNAL_SYSCALL (clock_gettime, __err, 2, CLOCK_REALTIME,

				      &now;;

		    reltime.tv_sec = abstime->tv_sec - now.tv_sec;

		    reltime.tv_nsec = abstime->tv_nsec - now.tv_nsec;

		    if (reltime.tv_nsec < 0)

		      {

			reltime.tv_nsec += 1000000000;

			--reltime.tv_sec;

		      }

		    if (reltime.tv_sec >= 0)

		      while (__nanosleep_nocancel (&reltime, &reltime) != 0)

			continue;

		    return ETIMEDOUT;

		  }

		return INTERNAL_SYSCALL_ERRNO (e, __err);

	      }

	    oldval = mutex->__data.__lock;

	    assert (robust || (oldval & FUTEX_OWNER_DIED) == 0);

	  }

	if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))

	  {

	    atomic_and (&mutex->__data.__lock, ~FUTEX_OWNER_DIED);

	    /* We got the mutex.  */

	    mutex->__data.__count = 1;

	    /* But it is inconsistent unless marked otherwise.  */

	    mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT;

	    /* We must not enqueue the mutex before we have acquired it.

	       Also see comments at ENQUEUE_MUTEX.  */

	    __asm ("" ::: "memory");

	    ENQUEUE_MUTEX_PI (mutex);

	    /* We need to clear op_pending after we enqueue the mutex.  */

	    __asm ("" ::: "memory");

	    THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

	    /* Note that we deliberately exit here.  If we fall

	       through to the end of the function __nusers would be

	       incremented which is not correct because the old owner

	       has to be discounted.  */

	    return EOWNERDEAD;

	  }

	if (robust

	    && __builtin_expect (mutex->__data.__owner

				 == PTHREAD_MUTEX_NOTRECOVERABLE, 0))

	  {

	    /* This mutex is now not recoverable.  */

	    mutex->__data.__count = 0;

	    INTERNAL_SYSCALL_DECL (__err);

	    INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock,

			      __lll_private_flag (FUTEX_UNLOCK_PI,

						  PTHREAD_ROBUST_MUTEX_PSHARED (mutex)),

			      0, 0);

	    /* To the kernel, this will be visible after the kernel has

	       acquired the mutex in the syscall.  */

	    THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

	    return ENOTRECOVERABLE;

	  }

	mutex->__data.__count = 1;

	if (robust)

	  {

	    /* We must not enqueue the mutex before we have acquired it.

	       Also see comments at ENQUEUE_MUTEX.  */

	    __asm ("" ::: "memory");

	    ENQUEUE_MUTEX_PI (mutex);

	    /* We need to clear op_pending after we enqueue the mutex.  */

	    __asm ("" ::: "memory");

	    THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);

	  }

	}

      break;

#endif  /* __NR_futex.  */

    case PTHREAD_MUTEX_PP_RECURSIVE_NP:

    case PTHREAD_MUTEX_PP_ERRORCHECK_NP:

    case PTHREAD_MUTEX_PP_NORMAL_NP:

    case PTHREAD_MUTEX_PP_ADAPTIVE_NP:

      {

	/* See concurrency notes regarding __kind in struct __pthread_mutex_s

	   in sysdeps/nptl/bits/thread-shared-types.h.  */

	int kind = atomic_load_relaxed (&(mutex->__data.__kind))

	  & PTHREAD_MUTEX_KIND_MASK_NP;

	oldval = mutex->__data.__lock;

	/* Check whether we already hold the mutex.  */

	if (mutex->__data.__owner == id)

	  {

	    if (kind == PTHREAD_MUTEX_ERRORCHECK_NP)

	      return EDEADLK;

	    if (kind == PTHREAD_MUTEX_RECURSIVE_NP)

	      {

		/* Just bump the counter.  */

		if (__glibc_unlikely (mutex->__data.__count + 1 == 0))

		  /* Overflow of the counter.  */

		  return EAGAIN;

		++mutex->__data.__count;

		LIBC_PROBE (mutex_timedlock_acquired, 1, mutex);

		return 0;

	      }

	  }

	int oldprio = -1, ceilval;

	do

	  {

	    int ceiling = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK)

			  >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;

	    if (__pthread_current_priority () > ceiling)

	      {

		result = EINVAL;

	      failpp:

		if (oldprio != -1)

		  __pthread_tpp_change_priority (oldprio, -1);

		return result;

	      }

	    result = __pthread_tpp_change_priority (oldprio, ceiling);

	    if (result)

	      return result;

	    ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT;

	    oldprio = ceiling;

	    oldval

	      = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,

						     ceilval | 1, ceilval);

	    if (oldval == ceilval)

	      break;

	    do

	      {

		oldval

		  = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,

							 ceilval | 2,

							 ceilval | 1);

		if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval)

		  break;

		if (oldval != ceilval)

		  {

		    /* Reject invalid timeouts.  */

		    if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)

		      {

			result = EINVAL;

			goto failpp;

		      }

		    struct timeval tv;

		    struct timespec rt;

		    /* Get the current time.  */

		    (void) __gettimeofday (&tv, NULL);

		    /* Compute relative timeout.  */

		    rt.tv_sec = abstime->tv_sec - tv.tv_sec;

		    rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;

		    if (rt.tv_nsec < 0)

		      {

			rt.tv_nsec += 1000000000;

			--rt.tv_sec;

		      }

		    /* Already timed out?  */

		    if (rt.tv_sec < 0)

		      {

			result = ETIMEDOUT;

			goto failpp;

		      }

		    lll_futex_timed_wait (&mutex->__data.__lock,

					  ceilval | 2, &rt,

					  PTHREAD_MUTEX_PSHARED (mutex));

		  }

	      }

	    while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,

							ceilval | 2, ceilval)

		   != ceilval);

	  }

	while ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval);

	assert (mutex->__data.__owner == 0);

	mutex->__data.__count = 1;

      }

      break;

    default:

      /* Correct code cannot set any other type.  */

      return EINVAL;

    }

  if (result == 0)

    {

      /* Record the ownership.  */

      mutex->__data.__owner = id;

      ++mutex->__data.__nusers;

      LIBC_PROBE (mutex_timedlock_acquired, 1, mutex);

    }

 out:

  return result;

}

weak_alias (__pthread_mutex_timedlock, pthread_mutex_timedlock)