Rich Felker
c68de0be2f
this change is needed to fix a race condition and ensure that it's possible to unlock and destroy or unmap the mutex as soon as pthread_mutex_lock succeeds. POSIX explicitly gives such an example in the rationale and requires an implementation to allow such usage.
32 lines
738 B
C
32 lines
738 B
C
#include "pthread_impl.h"
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int pthread_mutex_unlock(pthread_mutex_t *m)
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{
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pthread_t self;
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int waiters = m->_m_waiters;
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int cont;
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if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
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if (!m->_m_lock)
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return EPERM;
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self = __pthread_self();
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if ((m->_m_lock&0x1fffffff) != self->tid)
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return EPERM;
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if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && --m->_m_count)
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return 0;
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if (m->_m_type >= 4) {
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self->robust_list.pending = &m->_m_next;
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*(void **)m->_m_prev = m->_m_next;
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if (m->_m_next) ((void **)m->_m_next)[-1] = m->_m_prev;
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cont = a_swap(&m->_m_lock, 0);
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self->robust_list.pending = 0;
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goto wake;
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}
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}
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cont = a_swap(&m->_m_lock, 0);
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wake:
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if (waiters || cont<0)
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__wake(&m->_m_lock, 1, 0);
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return 0;
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}
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