glibc/nss/XXX-lookup.c

/* Copyright (C) 1996-2022 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <assert.h>
#include "nsswitch.h"

/*******************************************************************\
|* Here we assume one symbol to be defined:			   *|
|* 								   *|
|* DATABASE_NAME - name of the database the function accesses	   *|
|*		   (e.g., hosts, services, ...)			   *|
|* 								   *|
|* One additional symbol may optionally be defined:		   *|
|* 								   *|
|* ALTERNATE_NAME - name of another service which is examined in   *|
|*                  case DATABASE_NAME is not found                *|
|* 								   *|
|* DEFAULT_CONFIG - string for default conf (e.g. "files dns")	   *|
|* 								   *|
\*******************************************************************/

#define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup2)
#define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
#define CONCAT3_2(Pre, Name, Post) Pre##Name##Post

#define DATABASE_NAME_ID CONCAT2_1 (nss_database_, DATABASE_NAME)
#define CONCAT2_1(Pre, Name) CONCAT2_2 (Pre, Name)
#define CONCAT2_2(Pre, Name) Pre##Name

#define DATABASE_NAME_SYMBOL CONCAT3_1 (__nss_, DATABASE_NAME, _database)
#define DATABASE_NAME_STRING STRINGIFY1 (DATABASE_NAME)
#define STRINGIFY1(Name) STRINGIFY2 (Name)
#define STRINGIFY2(Name) #Name

int
DB_LOOKUP_FCT (nss_action_list *ni, const char *fct_name, const char *fct2_name,
	       void **fctp)
{
  if (! __nss_database_get (DATABASE_NAME_ID, &DATABASE_NAME_SYMBOL))
    return -1;

  *ni = DATABASE_NAME_SYMBOL;

  /* We want to know about it if we've somehow got a NULL action list;
   in the past, we had bad state if seccomp interfered with setup. */
  assert(*ni != NULL);

  return __nss_lookup (ni, fct_name, fct2_name, fctp);
}
libc_hidden_def (DB_LOOKUP_FCT)