Add build system scaffolding and libc headers

1 files changed, 37 insertions, 0 deletions

diff --git a/lib/libc/fcntl/fcntl.c b/lib/libc/fcntl/fcntl.c
new file mode 100644
index 00000000..ae213df5
--- /dev/null
+++ b/lib/libc/fcntl/fcntl.c
@@ -0,0 +1,37 @@
+#include <fcntl.h>
+#include <stdarg.h>
+#include <syscall.h>
+
+int fcntl(int fildes, int cmd, ...)
+{
+	unsigned long arg;
+	va_list ap;
+	va_start(ap, cmd);
+	arg = va_arg(ap, unsigned long);
+	va_end(ap);
+
+	if (cmd == F_DUPFD_CLOEXEC) {
+		int ret = syscall(fcntl, fildes, F_DUPFD_CLOEXEC, arg);
+		if (ret != -EINVAL) {
+			if (ret >= 0)
+				syscall(fcntl, ret, F_SETFD, FD_CLOEXEC);
+			return __syscall_ret(ret);
+		}
+
+		ret = syscall(fcntl, fildes, F_DUPFD_CLOEXEC, 0);
+		if (ret != -EINVAL) {
+			if (ret >= 0)
+				__syscall(close, ret);
+
+			return __syscall_ret(-EINVAL);
+		}
+
+		ret = syscall(fcntl, fildes, F_DUPFD, arg);
+		if (ret >= 0)
+			syscall(fcntl, ret, F_SETFD, FD_CLOEXEC);
+
+		return __syscall_ret(ret);
+	}
+
+	return syscall(fcntl, fildes, cmd);
+}