Initial Contribution
diff --git a/libc/nsswitch.h b/libc/nsswitch.h
new file mode 100644
index 0000000..e03844b
--- /dev/null
+++ b/libc/nsswitch.h
@@ -0,0 +1,237 @@
+/* $NetBSD: nsswitch.h,v 1.18 2005/11/29 03:12:58 christos 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.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the NetBSD
+ * Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * 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
+
+/*
+ * 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;
+
+
+#if 0
+/*
+ * 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[];
+#endif
+
+/*
+ * 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 [], ...);
+
+#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 */