cuserid: don't return truncated results

[musl] / src / thread / pthread_mutex_trylock.c

diff --git a/src/thread/pthread_mutex_trylock.c b/src/thread/pthread_mutex_trylock.c
index 29268fd..a24e7c5 100644 (file)
--- a/src/thread/pthread_mutex_trylock.c
+++ b/src/thread/pthread_mutex_trylock.c
@@ -1,28 +1,74 @@
 #include "pthread_impl.h"
 
-int pthread_mutex_trylock(pthread_mutex_t *m)
+int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
 {
-       if (m->_m_type == PTHREAD_MUTEX_RECURSIVE) {
-               pthread_t self = pthread_self();
-               if (m->_m_owner == self->tid) {
-                       if ((unsigned)m->_m_lock >= INT_MAX) return EAGAIN;
-                       a_inc(&m->_m_lock);
+       int old, own;
+       int type = m->_m_type;
+       pthread_t self = __pthread_self();
+       int tid = self->tid;
+
+       old = m->_m_lock;
+       own = old & 0x3fffffff;
+       if (own == tid) {
+               if ((type&8) && m->_m_count<0) {
+                       old &= 0x40000000;
+                       m->_m_count = 0;
+                       goto success;
+               }
+               if ((type&3) == PTHREAD_MUTEX_RECURSIVE) {
+                       if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
+                       m->_m_count++;
                        return 0;
                }
-               if (a_fetch_add(&m->_m_lock, 1)) {
-                       if (a_fetch_add(&m->_m_lock, -1)==1 && m->_m_waiters)
-                               __wake(&m->_m_lock, 1, 0);
-                       return EBUSY;
+       }
+       if (own == 0x3fffffff) return ENOTRECOVERABLE;
+       if (own || (old && !(type & 4))) return EBUSY;
+
+       if (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));
                }
-               m->_m_owner = self->tid;
-               return 0;
+               if (m->_m_waiters) tid |= 0x80000000;
+               self->robust_list.pending = &m->_m_next;
+       }
+       tid |= old & 0x40000000;
+
+       if (a_cas(&m->_m_lock, old, tid) != old) {
+               self->robust_list.pending = 0;
+               if ((type&12)==12 && m->_m_waiters) return ENOTRECOVERABLE;
+               return EBUSY;
+       }
+
+success:
+       if ((type&8) && m->_m_waiters) {
+               int priv = (type & 128) ^ 128;
+               __syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
+               self->robust_list.pending = 0;
+               return (type&4) ? ENOTRECOVERABLE : 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 (old) {
+               m->_m_count = 0;
+               return EOWNERDEAD;
        }
 
-       if (a_xchg(&m->_m_lock, 1))
-               if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK
-                && m->_m_owner == pthread_self()->tid) return EDEADLK;
-               else return EBUSY;
-       if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK)
-               m->_m_owner = pthread_self()->tid;
        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);