/* Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include <libc-lock.h>

#include "nsswitch.h"

/*******************************************************************\
|* Here we assume several symbols to be defined:		   *|
|* 								   *|
|* LOOKUP_TYPE   - the return type of the function		   *|
|* 								   *|
|* SETFUNC_NAME  - name of the non-reentrant setXXXent function	   *|
|* 								   *|
|* GETFUNC_NAME  - name of the non-reentrant getXXXent function	   *|
|* 								   *|
|* ENDFUNC_NAME  - name of the non-reentrant endXXXent function	   *|
|* 								   *|
|* DATABASE_NAME - name of the database the function accesses	   *|
|*		   (e.g., host, services, ...)			   *|
|* 								   *|
|* Optionally the following vars can be defined:		   *|
|* 								   *|
|* STAYOPEN      - variable declaration for setXXXent function	   *|
|* 								   *|
|* STAYOPEN_VAR  - variable name for setXXXent function		   *|
|* 								   *|
|* NEED_H_ERRNO  - an extra parameter will be passed to point to   *|
|*		   the global `h_errno' variable.		   *|
|* 								   *|
\*******************************************************************/

/* To make the real sources a bit prettier.  */
#define REENTRANT_GETNAME APPEND_R (GETFUNC_NAME)
#define APPEND_R(name) APPEND_R1 (name)
#define APPEND_R1(name) name##_r

#define SETFUNC_NAME_STRING STRINGIZE (SETFUNC_NAME)
#define GETFUNC_NAME_STRING STRINGIZE (GETFUNC_NAME)
#define ENDFUNC_NAME_STRING STRINGIZE (ENDFUNC_NAME)
#define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
#define STRINGIZE(name) STRINGIZE1 (name)
#define STRINGIZE1(name) #name

#define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup)
#define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
#define CONCAT3_2(Pre, Name, Post) Pre##Name##Post

/* Sometimes we need to store error codes in the `h_errno' variable.  */
#ifdef NEED_H_ERRNO
# define H_ERRNO_PARM , int *h_errnop
# define H_ERRNO_VAR , &h_errno
#else
# define H_ERRNO_PARM
# define H_ERRNO_VAR
#endif

/* Some databases take the `stayopen' flag.  */
#ifndef STAYOPEN
#define STAYOPEN void
#define STAYOPEN_VAR
#endif

/* Prototype for the setXXXent functions we use here.  */
typedef int (*set_function) (STAYOPEN);

/* Prototype for the endXXXent functions we use here.  */
typedef int (*end_function) (void);

/* Prototype for the setXXXent functions we use here.  */
typedef int (*get_function) (LOOKUP_TYPE *, char *, int H_ERRNO_PARM);


/* This handle for the NSS data base is shared between all
   set/get/endXXXent functions.  */
static service_user *nip;
/* Remember the first service_entry, it's always the same.  */
static service_user *startp;

/* Protect above variable against multiple uses at the same time.  */
__libc_lock_define_initialized (static, lock);

/* The lookup function for the first entry of this service.  */
extern int DB_LOOKUP_FCT (service_user **nip, const char *name, void **fctp);


void
SETFUNC_NAME (STAYOPEN)
{
  set_function fct;
  int no_more;

#ifdef NEED__RES
  if ((_res.options & RES_INIT) == 0 && res_init () == -1)
    {
      h_errno = NETDB_INTERNAL;
      return NULL;
    }
#endif /* need _res */

  __libc_lock_lock (lock);

  if (startp == NULL)
    {
      no_more = DB_LOOKUP_FCT (&nip, SETFUNC_NAME_STRING, (void **) &fct);
      startp = no_more == 0 ? (service_user *) -1 : nip;
    }
  else
    no_more = (nip = startp) != (service_user *) -1;

  /* Cycle through all the services and run their setXXent functions.  */
  while (! no_more)
    {
      /* Ignore status, we force check in __NSS_NEXT.  */
      (void) (*fct) (STAYOPEN_VAR);

      no_more = __nss_next (&nip, SETFUNC_NAME_STRING, (void **) &fct, 0, 1);
    }

  __libc_lock_unlock (lock);
}


void
ENDFUNC_NAME (void)
{
  end_function fct;
  int no_more;

#ifdef NEED__RES
  if ((_res.options & RES_INIT) == 0 && res_init () == -1)
    {
      h_errno = NETDB_INTERNAL;
      return NULL;
    }
#endif /* need _res */

  __libc_lock_lock (lock);

  if (startp == NULL)
    {
      no_more = DB_LOOKUP_FCT (&nip, SETFUNC_NAME_STRING, (void **) &fct);
      startp = no_more == 0 ? (service_user *) -1 : nip;
    }
  else
    no_more = (nip = startp) != (service_user *) -1;

  /* Cycle through all the services and run their endXXent functions.  */
  while (no_more == 0)
    {
      /* Ignore status, we force check in __NSS_NEXT.  */
      (void) (*fct) ();

      no_more = __nss_next (&nip, ENDFUNC_NAME_STRING, (void **) &fct, 0, 1);
    }

  __libc_lock_unlock (lock);
}


LOOKUP_TYPE *
REENTRANT_GETNAME (LOOKUP_TYPE *result, char *buffer, int buflen H_ERRNO_PARM)
{
  get_function fct;
  int no_more;
  enum nss_status status = NSS_STATUS_NOTFOUND;

#ifdef NEED__RES
  if ((_res.options & RES_INIT) == 0 && res_init () == -1)
    {
      h_errno = NETDB_INTERNAL;
      return NULL;
    }
#endif /* need _res */

  __libc_lock_lock (lock);

  if (nip)
    /* Continuing a walk-through started before.  */
    no_more = 0;
  else
    {
      if (startp == NULL)
	{
	  no_more = DB_LOOKUP_FCT (&nip, SETFUNC_NAME_STRING, (void **) &fct);
	  startp = no_more == 0 ? (service_user *) -1 : nip;
	}
      else
	no_more = (nip = startp) != (service_user *) -1;

      if (no_more != 0)
	status = NSS_STATUS_UNAVAIL;
    }

  while (no_more == 0)
    {
      status = (*fct) (result, buffer, buflen H_ERRNO_VAR);

      no_more = __nss_next (&nip, GETFUNC_NAME_STRING, (void **) &fct,
			    status, 0);
    }

  __libc_lock_unlock (lock);

  return status == NSS_STATUS_SUCCESS ? result : NULL;
}
