#include "pthread_impl.h"
+#include "syscall.h"
+
+static pthread_once_t check_pi_once;
+static int check_pi_result;
+
+static void check_pi()
+{
+ volatile int lk = 0;
+ check_pi_result = -__syscall(SYS_futex, &lk, FUTEX_LOCK_PI, 0, 0);
+}
int pthread_mutexattr_setprotocol(pthread_mutexattr_t *a, int protocol)
{
- if (protocol) return ENOTSUP;
- return 0;
+ switch (protocol) {
+ case PTHREAD_PRIO_NONE:
+ a->__attr &= ~8;
+ return 0;
+ case PTHREAD_PRIO_INHERIT:
+ pthread_once(&check_pi_once, check_pi);
+ if (check_pi_result) return check_pi_result;
+ a->__attr |= 8;
+ return 0;
+ case PTHREAD_PRIO_PROTECT:
+ return ENOTSUP;
+ default:
+ return EINVAL;
+ }
}