1 files changed, 17 insertions, 6 deletions
diff --git a/libc/private/bionic_futex.h b/libc/private/bionic_futex.h
index 11699ce..dd277ed 100644
--- a/libc/private/bionic_futex.h
+++ b/libc/private/bionic_futex.h
@@ -28,31 +28,42 @@
 #ifndef _BIONIC_FUTEX_H
 #define _BIONIC_FUTEX_H
 
+#include <errno.h>
 #include <linux/futex.h>
-#include <sys/cdefs.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <sys/cdefs.h>
+#include <sys/syscall.h>
 
 __BEGIN_DECLS
 
 struct timespec;
 
-extern int __futex_syscall4(volatile void* ftx, int op, int value, const struct timespec* timeout);
+static inline int __futex(volatile void* ftx, int op, int value, const struct timespec* timeout) {
+  // Our generated syscall assembler sets errno, but our callers (pthread functions) don't want to.
+  int saved_errno = errno;
+  if (syscall(__NR_futex, ftx, op, value, timeout) == 0) {
+    return 0;
+  }
+  int result = -errno;
+  errno = saved_errno;
+  return result;
+}
 
 static inline int __futex_wake(volatile void* ftx, int count) {
-  return __futex_syscall4(ftx, FUTEX_WAKE, count, NULL);
+  return __futex(ftx, FUTEX_WAKE, count, NULL);
 }
 
 static inline int __futex_wake_ex(volatile void* ftx, bool shared, int count) {
-  return __futex_syscall4(ftx, shared ? FUTEX_WAKE : FUTEX_WAKE_PRIVATE, count, NULL);
+  return __futex(ftx, shared ? FUTEX_WAKE : FUTEX_WAKE_PRIVATE, count, NULL);
 }
 
 static inline int __futex_wait(volatile void* ftx, int value, const struct timespec* timeout) {
-  return __futex_syscall4(ftx, FUTEX_WAIT, value, timeout);
+  return __futex(ftx, FUTEX_WAIT, value, timeout);
 }
 
 static inline int __futex_wait_ex(volatile void* ftx, bool shared, int value, const struct timespec* timeout) {
-  return __futex_syscall4(ftx, shared ? FUTEX_WAIT : FUTEX_WAIT_PRIVATE, value, timeout);
+  return __futex(ftx, shared ? FUTEX_WAIT : FUTEX_WAIT_PRIVATE, value, timeout);
 }
 
 __END_DECLS