make sem_wait and sem_timedwait interruptible by signals

[musl] / src / thread / pthread_mutex_trylock.c

diff --git a/src/thread/pthread_mutex_trylock.c b/src/thread/pthread_mutex_trylock.c
index 7ff4f70..783ca0c 100644 (file)
--- a/src/thread/pthread_mutex_trylock.c
+++ b/src/thread/pthread_mutex_trylock.c
@@ -1,25 +1,58 @@
 #include "pthread_impl.h"
 
-int pthread_mutex_trylock(pthread_mutex_t *m)
+int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
 {
-       pthread_t self;
-       if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
-               self = pthread_self();
-               if (m->_m_type == PTHREAD_MUTEX_RECURSIVE
-                && m->_m_owner == self->tid) {
-                       if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
-                       m->_m_count++;
-                       return 0;
+       int old, own;
+       int type = m->_m_type & 15;
+       pthread_t self = __pthread_self();
+       int tid = self->tid;
+
+       old = m->_m_lock;
+       own = old & 0x7fffffff;
+       if (own == tid && (type&3) == PTHREAD_MUTEX_RECURSIVE) {
+               if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
+               m->_m_count++;
+               return 0;
+       }
+       if (own == 0x7fffffff) return ENOTRECOVERABLE;
+       if (own && (!(own & 0x40000000) || !(type & 4))) return EBUSY;
+
+       if (m->_m_type & 128) {
+               if (!self->robust_list.off) {
+                       self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
+                       __syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
                }
+               if (m->_m_waiters) tid |= 0x80000000;
+               self->robust_list.pending = &m->_m_next;
        }
 
-       if (a_xchg(&m->_m_lock, 1))
-               if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK
-                && m->_m_owner == self->tid) return EDEADLK;
-               else return EBUSY;
-       if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
-               m->_m_owner = self->tid;
-               m->_m_count = 1;
+       if (a_cas(&m->_m_lock, old, tid) != old) {
+               self->robust_list.pending = 0;
+               return EBUSY;
+       }
+
+       volatile void *next = self->robust_list.head;
+       m->_m_next = next;
+       m->_m_prev = &self->robust_list.head;
+       if (next != &self->robust_list.head) *(volatile void *volatile *)
+               ((char *)next - sizeof(void *)) = &m->_m_next;
+       self->robust_list.head = &m->_m_next;
+       self->robust_list.pending = 0;
+
+       if (own) {
+               m->_m_count = 0;
+               m->_m_type |= 8;
+               return EOWNERDEAD;
        }
+
        return 0;
 }
+
+int __pthread_mutex_trylock(pthread_mutex_t *m)
+{
+       if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL)
+               return a_cas(&m->_m_lock, 0, EBUSY) & EBUSY;
+       return __pthread_mutex_trylock_owner(m);
+}
+
+weak_alias(__pthread_mutex_trylock, pthread_mutex_trylock);