56 lines
873 B
C
56 lines
873 B
C
#include <u.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include <sched.h>
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#include <errno.h>
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#include <libc.h>
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static pthread_mutex_t initmutex = PTHREAD_MUTEX_INITIALIZER;
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static void
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lockinit(Lock *lk)
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{
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pthread_mutexattr_t attr;
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pthread_mutex_lock(&initmutex);
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if(lk->init == 0){
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pthread_mutexattr_init(&attr);
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pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
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pthread_mutex_init(&lk->mutex, &attr);
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pthread_mutexattr_destroy(&attr);
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lk->init = 1;
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}
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pthread_mutex_unlock(&initmutex);
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}
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void
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lock(Lock *lk)
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{
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if(!lk->init)
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lockinit(lk);
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if(pthread_mutex_lock(&lk->mutex) != 0)
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abort();
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}
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int
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canlock(Lock *lk)
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{
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int r;
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if(!lk->init)
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lockinit(lk);
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r = pthread_mutex_trylock(&lk->mutex);
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if(r == 0)
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return 1;
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if(r == EBUSY)
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return 0;
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abort();
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}
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void
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unlock(Lock *lk)
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{
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if(pthread_mutex_unlock(&lk->mutex) != 0)
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abort();
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}
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