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| | #include "pthread_impl.h"
#define IS32BIT(x) !((x)+0x80000000ULL>>32)
#define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63))
static int __futex4(volatile void *addr, int op, int val, const struct timespec *to)
{
#ifdef SYS_futex_time64
time_t s = to ? to->tv_sec : 0;
long ns = to ? to->tv_nsec : 0;
int r = __syscall(SYS_futex_time64, addr, op, val,
to ? ((long long[]){s, ns}) : 0);
if (SYS_futex == SYS_futex_time64 || r!=-ENOSYS) return r;
to = to ? (void *)(long[]){CLAMP(s), ns} : 0;
#endif
return __syscall(SYS_futex, addr, op, val, to);
}
static int pthread_mutex_timedlock_pi(pthread_mutex_t *restrict m, const struct timespec *restrict at)
{
int type = m->_m_type;
int priv = (type & 128) ^ 128;
pthread_t self = __pthread_self();
int e;
if (!priv) self->robust_list.pending = &m->_m_next;
do e = -__futex4(&m->_m_lock, FUTEX_LOCK_PI|priv, 0, at);
while (e==EINTR);
if (e) self->robust_list.pending = 0;
switch (e) {
case 0:
/* Catch spurious success for non-robust mutexes. */
if (!(type&4) && ((m->_m_lock & 0x40000000) || m->_m_waiters)) {
a_store(&m->_m_waiters, -1);
__syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
self->robust_list.pending = 0;
break;
}
/* Signal to trylock that we already have the lock. */
m->_m_count = -1;
return __pthread_mutex_trylock(m);
case ETIMEDOUT:
return e;
case EDEADLK:
if ((type&3) == PTHREAD_MUTEX_ERRORCHECK) return e;
}
do e = __timedwait(&(int){0}, 0, CLOCK_REALTIME, at, 1);
while (e != ETIMEDOUT);
return e;
}
int __pthread_mutex_timedlock(pthread_mutex_t *restrict m, const struct timespec *restrict at)
{
if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL
&& !a_cas(&m->_m_lock, 0, EBUSY))
return 0;
int type = m->_m_type;
int r, t, priv = (type & 128) ^ 128;
r = __pthread_mutex_trylock(m);
if (r != EBUSY) return r;
if (type&8) return pthread_mutex_timedlock_pi(m, at);
int spins = 100;
while (spins-- && m->_m_lock && !m->_m_waiters) a_spin();
while ((r=__pthread_mutex_trylock(m)) == EBUSY) {
r = m->_m_lock;
int own = r & 0x3fffffff;
if (!own && (!r || (type&4)))
continue;
if ((type&3) == PTHREAD_MUTEX_ERRORCHECK
&& own == __pthread_self()->tid)
return EDEADLK;
a_inc(&m->_m_waiters);
t = r | 0x80000000;
a_cas(&m->_m_lock, r, t);
r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, priv);
a_dec(&m->_m_waiters);
if (r && r != EINTR) break;
}
return r;
}
weak_alias(__pthread_mutex_timedlock, pthread_mutex_timedlock);
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