1 files changed, 10 insertions, 0 deletions
diff --git a/src/unistd/dup2.c b/src/unistd/dup2.c
index 87a0d445..8f43c6dd 100644
--- a/src/unistd/dup2.c
+++ b/src/unistd/dup2.c
@@ -1,10 +1,20 @@
 #include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
 #include "syscall.h"
 
 int dup2(int old, int new)
 {
 	int r;
+#ifdef SYS_dup2
 	while ((r=__syscall(SYS_dup2, old, new))==-EBUSY);
+#else
+	if (old==new) {
+		r = __syscall(SYS_fcntl, old, F_GETFD);
+		if (r >= 0) return old;
+	} else {
+		while ((r=__syscall(SYS_dup3, old, new, 0))==-EBUSY);
+	}
+#endif
 	return __syscall_ret(r);
 }