1 files changed, 82 insertions, 0 deletions
diff --git a/lib/libc/sys/lockf.c b/lib/libc/sys/lockf.c
new file mode 100644
index 000000000000..6211275e5f16
--- /dev/null
+++ b/lib/libc/sys/lockf.c
@@ -0,0 +1,82 @@
+/*	$NetBSD: lockf.c,v 1.3 2008/04/28 20:22:59 martin Exp $	*/
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 1997 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Klaus Klein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "namespace.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include "un-namespace.h"
+#include "libc_private.h"
+
+int
+lockf(int filedes, int function, off_t size)
+{
+	struct flock fl;
+	int cmd;
+
+	fl.l_start = 0;
+	fl.l_len = size;
+	fl.l_whence = SEEK_CUR;
+
+	switch (function) {
+	case F_ULOCK:
+		cmd = F_SETLK;
+		fl.l_type = F_UNLCK;
+		break;
+	case F_LOCK:
+		cmd = F_SETLKW;
+		fl.l_type = F_WRLCK;
+		break;
+	case F_TLOCK:
+		cmd = F_SETLK;
+		fl.l_type = F_WRLCK;
+		break;
+	case F_TEST:
+		fl.l_type = F_WRLCK;
+		if (((int (*)(int, int, ...))
+		    *(__libc_interposing_slot(INTERPOS_fcntl)))
+		    (filedes, F_GETLK, &fl) == -1)
+			return (-1);
+		if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 &&
+		    fl.l_pid == getpid()))
+			return (0);
+		errno = EAGAIN;
+		return (-1);
+		/* NOTREACHED */
+	default:
+		errno = EINVAL;
+		return (-1);
+		/* NOTREACHED */
+	}
+
+	return (INTERPOS_SYS(fcntl, filedes, cmd, (intptr_t)&fl));
+}