diff --git a/dios/include/dlfcn.h b/dios/include/dlfcn.h
index 009132bcb1977360d5dcdcc9661bcc812bcdc159..431065f3eab32299ad39766592e72a1765c8e8dc 100644
--- a/dios/include/dlfcn.h
+++ b/dios/include/dlfcn.h
@@ -1 +1,98 @@
-/* not available */
+/*	$OpenBSD: dlfcn.h,v 1.14 2017/11/28 17:19:47 kettenis Exp $	*/
+/*	$NetBSD: dlfcn.h,v 1.2 1995/06/05 19:38:00 pk Exp $	*/
+
+/*
+ * Copyright (c) 1995 Paul Kranenburg
+ * All rights reserved.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by Paul Kranenburg.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+
+#ifndef _DLFCN_H_
+#define _DLFCN_H_
+
+#include <sys/cdefs.h>
+
+/* Values for dlopen `mode'. */
+#define RTLD_LAZY	1
+#define RTLD_NOW	2
+#define RTLD_GLOBAL	0x100
+#define RTLD_LOCAL	0x000
+#define RTLD_TRACE	0x200
+
+/*
+ * Special handle arguments for dlsym().
+ */
+#define	RTLD_NEXT	((void *) -1)	/* Search subsequent objects. */
+#define	RTLD_DEFAULT	((void *) -2)	/* Use default search algorithm. */
+#define	RTLD_SELF	((void *) -3)	/* Search the caller itself. */
+
+#if __BSD_VISIBLE
+
+/*
+ * Structure filled in by dladdr().
+ */
+typedef	struct dl_info {
+	const char	*dli_fname;	/* Pathname of shared object. */
+	void		*dli_fbase;	/* Base address of shared object. */
+	const char	*dli_sname;	/* Name of nearest symbol. */
+	void		*dli_saddr;	/* Address of nearest symbol. */
+} Dl_info;
+
+/*
+ * dlctl() commands
+ */
+#define DL_GETERRNO	1
+#define DL_SETSRCHPATH	x
+#define DL_GETLIST	x
+#define DL_GETREFCNT	x
+#define DL_GETLOADADDR	x
+#define DL_SETTHREADLCK	2
+#define DL_SETBINDLCK	3
+#define DL_REFERENCE	4
+
+#define	DL_LAZY		RTLD_LAZY	/* Compat */
+
+#endif /* __BSD_VISIBLE */
+
+
+/*
+ * User interface to the run-time linker.
+ */
+__BEGIN_DECLS
+void	*dlopen(const char *, int);
+int	dlclose(void *);
+void	*dlsym(void *__restrict, const char *__restrict);
+char	*dlerror(void);
+
+#if __BSD_VISIBLE
+int	dladdr(const void *, Dl_info *);
+int	dlctl(void *, int, void *);
+#endif /* __BSD_VISIBLE */
+
+__END_DECLS
+
+#endif /* _DLFCN_H_ */