diff --git a/libc/include/nsswitch.h b/libc/include/nsswitch.h
new file mode 100644
index 0000000..af88433
--- /dev/null
+++ b/libc/include/nsswitch.h
@@ -0,0 +1,230 @@
+/*	$NetBSD: nsswitch.h,v 1.21 2011/07/17 20:54:34 joerg Exp $	*/
+
+/*-
+ * Copyright (c) 1997, 1998, 1999, 2004 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Luke Mewburn.
+ *
+ * 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.
+ */
+
+#ifndef _NSSWITCH_H
+#define _NSSWITCH_H	1
+
+#include <sys/types.h>
+#include <stdarg.h>
+
+#define	NSS_MODULE_INTERFACE_VERSION	0
+
+#ifndef _PATH_NS_CONF
+#define _PATH_NS_CONF	"/etc/nsswitch.conf"
+#endif
+
+#define	NS_CONTINUE	0
+#define	NS_RETURN	1
+
+/*
+ * Layout of:
+ *	uint32_t ns_src.flags
+ */
+	/* nsswitch.conf status codes and nsdispatch(3) return values */
+#define	NS_SUCCESS	(1<<0)		/* entry was found */
+#define	NS_UNAVAIL	(1<<1)		/* source not responding, or corrupt */
+#define	NS_NOTFOUND	(1<<2)		/* source responded 'no such entry' */
+#define	NS_TRYAGAIN	(1<<3)		/* source busy, may respond to retrys */
+#define	NS_STATUSMASK	0x000000ff	/* bitmask to get the status flags */
+
+	/* internal nsdispatch(3) flags; not settable in nsswitch.conf(5)  */
+#define	NS_FORCEALL	(1<<8)		/* force all methods to be invoked; */
+
+/*
+ * Currently implemented sources.
+ */
+#define NSSRC_FILES	"files"		/* local files */
+#define	NSSRC_DNS	"dns"		/* DNS; IN for hosts, HS for others */
+#define	NSSRC_NIS	"nis"		/* YP/NIS */
+#define	NSSRC_COMPAT	"compat"	/* passwd,group in YP compat mode */
+
+/*
+ * Currently implemented databases.
+ */
+#define NSDB_HOSTS		"hosts"
+#define NSDB_GROUP		"group"
+#define NSDB_GROUP_COMPAT	"group_compat"
+#define NSDB_NETGROUP		"netgroup"
+#define NSDB_NETWORKS		"networks"
+#define NSDB_PASSWD		"passwd"
+#define NSDB_PASSWD_COMPAT	"passwd_compat"
+#define NSDB_SHELLS		"shells"
+
+/*
+ * Suggested databases to implement.
+ */
+#define NSDB_ALIASES		"aliases"
+#define NSDB_AUTH		"auth"
+#define NSDB_AUTOMOUNT		"automount"
+#define NSDB_BOOTPARAMS		"bootparams"
+#define NSDB_ETHERS		"ethers"
+#define NSDB_EXPORTS		"exports"
+#define NSDB_NETMASKS		"netmasks"
+#define NSDB_PHONES		"phones"
+#define NSDB_PRINTCAP		"printcap"
+#define NSDB_PROTOCOLS		"protocols"
+#define NSDB_REMOTE		"remote"
+#define NSDB_RPC		"rpc"
+#define NSDB_SENDMAILVARS	"sendmailvars"
+#define NSDB_SERVICES		"services"
+#define NSDB_TERMCAP		"termcap"
+#define NSDB_TTYS		"ttys"
+
+/*
+ * ns_dtab `callback' function signature.
+ */
+typedef	int (*nss_method)(void *, void *, va_list);
+
+/*
+ * ns_dtab - `nsswitch dispatch table'
+ * Contains an entry for each source and the appropriate function to call.
+ */
+typedef struct {
+	const char	 *src;
+	nss_method	 callback;
+	void		 *cb_data;
+} ns_dtab;
+
+/*
+ * Macros to help build an ns_dtab[]
+ */
+#define NS_FILES_CB(F,C)	{ NSSRC_FILES,	F,	__UNCONST(C) },
+#define NS_COMPAT_CB(F,C)	{ NSSRC_COMPAT,	F,	__UNCONST(C) },
+
+#ifdef HESIOD
+#   define NS_DNS_CB(F,C)	{ NSSRC_DNS,	F,	__UNCONST(C) },
+#else
+#   define NS_DNS_CB(F,C)
+#endif
+
+#ifdef YP
+#   define NS_NIS_CB(F,C)	{ NSSRC_NIS,	F,	__UNCONST(C) },
+#else
+#   define NS_NIS_CB(F,C)
+#endif
+#define	NS_NULL_CB		{ .src = NULL },
+
+/*
+ * ns_src - `nsswitch source'
+ * Used by the nsparser routines to store a mapping between a source
+ * and its dispatch control flags for a given database.
+ */
+typedef struct {
+	const char	*name;
+	uint32_t	 flags;
+} ns_src;
+
+
+/*
+ * Default sourcelists (if nsswitch.conf is missing, corrupt,
+ * or the requested database doesn't have an entry)
+ */
+extern const ns_src __nsdefaultsrc[];
+extern const ns_src __nsdefaultcompat[];
+extern const ns_src __nsdefaultcompat_forceall[];
+extern const ns_src __nsdefaultfiles[];
+extern const ns_src __nsdefaultfiles_forceall[];
+extern const ns_src __nsdefaultnis[];
+extern const ns_src __nsdefaultnis_forceall[];
+
+
+/*
+ * ns_mtab - `nsswitch method table'
+ * An nsswitch module provides a mapping from (database name, method name)
+ * tuples to the nss_method and associated callback data.  Effectively,
+ * ns_dtab, but used for dynamically loaded modules.
+ */
+typedef struct {
+	const char	*database;
+	const char	*name;
+	nss_method	 method;
+	void		*mdata;
+} ns_mtab;
+
+/*
+ * nss_module_register_fn - module registration function
+ *	called at module load
+ * nss_module_unregister_fn - module un-registration function
+ *	called at module unload
+ */
+typedef	void (*nss_module_unregister_fn)(ns_mtab *, u_int);
+typedef	ns_mtab *(*nss_module_register_fn)(const char *, u_int *,
+					   nss_module_unregister_fn *);
+
+#ifdef _NS_PRIVATE
+
+/*
+ * Private data structures for back-end nsswitch implementation.
+ */
+
+/*
+ * ns_dbt - `nsswitch database thang'
+ * For each database in /etc/nsswitch.conf there is a ns_dbt, with its
+ * name and a list of ns_src's containing the source information.
+ */
+typedef struct {
+	const char	*name;		/* name of database */
+	ns_src		*srclist;	/* list of sources */
+	u_int		 srclistsize;	/* size of srclist */
+} ns_dbt;
+
+/*
+ * ns_mod - `nsswitch module'
+ */
+typedef struct {
+	const char	*name;		/* module name */
+	void		*handle;	/* handle from dlopen() */
+	ns_mtab		*mtab;		/* method table */
+	u_int		 mtabsize;	/* size of mtab */
+					/* called to unload module */
+	nss_module_unregister_fn unregister;
+} ns_mod;
+
+#endif /* _NS_PRIVATE */
+
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+int	nsdispatch(void *, const ns_dtab [], const char *,
+			const char *, const ns_src [], ...) __LIBC_ABI_PUBLIC__;
+
+#ifdef _NS_PRIVATE
+int		 _nsdbtaddsrc(ns_dbt *, const ns_src *);
+void		 _nsdbtdump(const ns_dbt *);
+int		 _nsdbtput(const ns_dbt *);
+void		 _nsyyerror(const char *);
+int		 _nsyylex(void);
+#endif /* _NS_PRIVATE */
+
+__END_DECLS
+
+#endif /* !_NSSWITCH_H */