fix shutdown

kernel-src/sys/syscalls/shutdown.c

@@ -0,0 +1,38 @@
+#include <kernel/syscalls.h>
+#include <errno.h>
+#include <string.h>
+#include <kernel/alloc.h>
+#include <kernel/sock.h>
+#include <kernel/file.h>
+#include <kernel/vfs.h>
+#include <kernel/net.h>
+#include <logging.h>
+
+syscallret_t syscall_shutdown(context_t *, int fd, int how) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	++how; // convert to internal meaning
+	
+	file_t *file = fd_get(fd);
+	if (file == NULL) {
+		ret.errno = EBADF;
+		return ret;
+	}
+
+	if (file->vnode->type != V_TYPE_SOCKET) {
+		ret.errno = ENOTSOCK;
+		goto cleanup;
+	}
+
+	socket_t *socket = SOCKFS_SOCKET_FROM_NODE(file->vnode);
+
+	ret.errno = socket->ops->shutdown(socket, how);
+	ret.ret = ret.errno ? -1 : 0;
+
+	cleanup:
+
+	fd_release(file);
+	return ret;
+}