Rich Felker
c0ed5a201b
per POSIX, the EINTR condition is an optional error for these functions, not a mandatory one. since old kernels (pre-2.6.22) failed to honor SA_RESTART for the futex syscall, it's dangerous to trust EINTR from the kernel. thankfully POSIX offers an easy way out.
31 lines
594 B
C
31 lines
594 B
C
#include <semaphore.h>
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#include "pthread_impl.h"
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static void cleanup(void *p)
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{
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a_dec(p);
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}
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int sem_timedwait(sem_t *restrict sem, const struct timespec *restrict at)
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{
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pthread_testcancel();
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if (!sem_trywait(sem)) return 0;
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int spins = 100;
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while (spins-- && sem->__val[0] <= 0 && !sem->__val[1]) a_spin();
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while (sem_trywait(sem)) {
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int r;
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a_inc(sem->__val+1);
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a_cas(sem->__val, 0, -1);
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r = __timedwait(sem->__val, -1, CLOCK_REALTIME, at, cleanup, sem->__val+1, sem->__val[2]);
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a_dec(sem->__val+1);
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if (r && r != EINTR) {
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errno = r;
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return -1;
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}
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}
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return 0;
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}
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