75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
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#include "pthread_impl.h"
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int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
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{
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int old, own;
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int type = m->_m_type;
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pthread_t self = __pthread_self();
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int tid = self->tid;
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old = m->_m_lock;
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own = old & 0x3fffffff;
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if (own == tid) {
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if ((type&8) && m->_m_count<0) {
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old &= 0x40000000;
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m->_m_count = 0;
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goto success;
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}
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if ((type&3) == PTHREAD_MUTEX_RECURSIVE) {
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if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
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m->_m_count++;
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return 0;
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}
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}
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if (own == 0x3fffffff) return ENOTRECOVERABLE;
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if (own || (old && !(type & 4))) return EBUSY;
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if (type & 128) {
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if (!self->robust_list.off) {
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self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
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__syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
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}
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if (m->_m_waiters) tid |= 0x80000000;
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self->robust_list.pending = &m->_m_next;
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}
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tid |= old & 0x40000000;
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if (a_cas(&m->_m_lock, old, tid) != old) {
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self->robust_list.pending = 0;
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if ((type&12)==12 && m->_m_waiters) return ENOTRECOVERABLE;
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return EBUSY;
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}
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success:
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if ((type&8) && m->_m_waiters) {
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int priv = (type & 128) ^ 128;
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__syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
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self->robust_list.pending = 0;
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return (type&4) ? ENOTRECOVERABLE : EBUSY;
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}
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volatile void *next = self->robust_list.head;
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m->_m_next = next;
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m->_m_prev = &self->robust_list.head;
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if (next != &self->robust_list.head) *(volatile void *volatile *)
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((char *)next - sizeof(void *)) = &m->_m_next;
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self->robust_list.head = &m->_m_next;
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self->robust_list.pending = 0;
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if (old) {
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m->_m_count = 0;
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return EOWNERDEAD;
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}
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return 0;
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}
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int __pthread_mutex_trylock(pthread_mutex_t *m)
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{
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if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL)
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return a_cas(&m->_m_lock, 0, EBUSY) & EBUSY;
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return __pthread_mutex_trylock_owner(m);
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}
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weak_alias(__pthread_mutex_trylock, pthread_mutex_trylock);
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