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042e1521c7
This commit fixes semaphore destruction by either using 64b atomic operations (where available), or by using two separate fields when only 32b atomic operations are available. In the latter case, we keep a conservative estimate of whether there are any waiting threads in one bit of the field that counts the number of available tokens, thus allowing sem_post to atomically both add a token and determine whether it needs to call futex_wake. See: https://sourceware.org/ml/libc-alpha/2014-12/msg00155.html
76 lines
1.4 KiB
C
76 lines
1.4 KiB
C
#include <errno.h>
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#include <semaphore.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <internaltypes.h>
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static int
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do_test (void)
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{
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union
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{
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sem_t s;
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struct new_sem ns;
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} u;
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if (sem_init (&u.s, 0, 0) != 0)
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{
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puts ("sem_init failed");
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return 1;
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}
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struct timespec ts = { 0, 1000000001 }; /* Invalid. */
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errno = 0;
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if (sem_timedwait (&u.s, &ts) >= 0)
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{
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puts ("sem_timedwait did not fail");
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return 1;
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}
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if (errno != EINVAL)
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{
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perror ("sem_timedwait did not fail with EINVAL");
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return 1;
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}
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#if __HAVE_64B_ATOMICS
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unsigned int nwaiters = (u.ns.data >> SEM_NWAITERS_SHIFT);
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#else
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unsigned int nwaiters = u.ns.nwaiters;
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#endif
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if (nwaiters != 0)
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{
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printf ("sem_timedwait modified nwaiters: %d\n", nwaiters);
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return 1;
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}
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ts.tv_sec = /* Invalid. */ -2;
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ts.tv_nsec = 0;
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errno = 0;
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if (sem_timedwait (&u.s, &ts) >= 0)
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{
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puts ("2nd sem_timedwait did not fail");
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return 1;
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}
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if (errno != ETIMEDOUT)
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{
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perror ("2nd sem_timedwait did not fail with ETIMEDOUT");
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return 1;
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}
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#if __HAVE_64B_ATOMICS
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nwaiters = (u.ns.data >> SEM_NWAITERS_SHIFT);
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#else
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nwaiters = u.ns.nwaiters;
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#endif
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if (nwaiters != 0)
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{
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printf ("2nd sem_timedwait modified nwaiters: %d\n", nwaiters);
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return 1;
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}
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return 0;
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}
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#define TEST_FUNCTION do_test ()
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#include "../test-skeleton.c"
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