1 | #include "pthread_impl.h"
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2 |
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3 | int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
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4 | {
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5 | int old, own;
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6 | int type = m->_m_type & 15;
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7 | pthread_t self = __pthread_self();
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8 | int tid = self->tid;
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9 |
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10 | old = m->_m_lock;
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11 | own = old & 0x7fffffff;
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12 | if (own == tid && (type&3) == PTHREAD_MUTEX_RECURSIVE) {
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13 | if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
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14 | m->_m_count++;
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15 | return 0;
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16 | }
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17 | if (own == 0x7fffffff) return ENOTRECOVERABLE;
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18 |
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19 | if (m->_m_type & 128) {
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20 | if (!self->robust_list.off) {
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21 | self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
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22 | __syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
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23 | }
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24 | if (m->_m_waiters) tid |= 0x80000000;
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25 | self->robust_list.pending = &m->_m_next;
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26 | }
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27 |
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28 | if ((own && (!(own & 0x40000000) || !(type & 4)))
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29 | || a_cas(&m->_m_lock, old, tid) != old) {
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30 | self->robust_list.pending = 0;
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31 | return EBUSY;
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32 | }
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33 |
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34 | volatile void *next = self->robust_list.head;
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35 | m->_m_next = next;
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36 | m->_m_prev = &self->robust_list.head;
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37 | if (next != &self->robust_list.head) *(volatile void *volatile *)
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38 | ((char *)next - sizeof(void *)) = &m->_m_next;
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39 | self->robust_list.head = &m->_m_next;
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40 | self->robust_list.pending = 0;
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41 |
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42 | if (own) {
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43 | m->_m_count = 0;
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44 | m->_m_type |= 8;
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45 | return EOWNERDEAD;
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46 | }
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47 |
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48 | return 0;
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49 | }
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50 |
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51 | int __pthread_mutex_trylock(pthread_mutex_t *m)
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52 | {
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53 | if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL)
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54 | return a_cas(&m->_m_lock, 0, EBUSY) & EBUSY;
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55 | return __pthread_mutex_trylock_owner(m);
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56 | }
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57 |
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58 | weak_alias(__pthread_mutex_trylock, pthread_mutex_trylock);
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