nss/nsswitch.h

   1 /* Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #ifndef _NSSWITCH_H
  20 #define _NSSWITCH_H     1
  21
  22 /* This is an *internal* header.  */
  23
  24 #include <arpa/nameser.h>
  25 #include <netinet/in.h>
  26 #include <nss.h>
  27 #include <resolv.h>
  28 #include <search.h>
  29 #include <dlfcn.h>
  30
  31 /* Actions performed after lookup finished.  */
  32 typedef enum
  33 {
  34   NSS_ACTION_CONTINUE,
  35   NSS_ACTION_RETURN
  36 } lookup_actions;
  37
  38
  39 typedef struct service_library
  40 {
  41   /* Name of service (`files', `dns', `nis', ...).  */
  42   const char *name;
  43   /* Pointer to the loaded shared library.  */
  44   void *lib_handle;
  45   /* And the link to the next entry.  */
  46   struct service_library *next;
  47 } service_library;
  48
  49
  50 /* For mapping a function name to a function pointer.  It is known in
  51    nsswitch.c:nss_lookup_function that a string pointer for the lookup key
  52    is the first member.  */
  53 typedef struct
  54 {
  55   const char *fct_name;
  56   void *fct_ptr;
  57 } known_function;
  58
  59
  60 typedef struct service_user
  61 {
  62   /* And the link to the next entry.  */
  63   struct service_user *next;
  64   /* Action according to result.  */
  65   lookup_actions actions[5];
  66   /* Link to the underlying library object.  */
  67   service_library *library;
  68   /* Collection of known functions.  */
  69   struct entry *known;
  70   /* Name of the service (`files', `dns', `nis', ...).  */
  71   char name[0];
  72 } service_user;
  73
  74 /* To access the action based on the status value use this macro.  */
  75 #define nss_next_action(ni, status) ((ni)->actions[2 + status])
  76
  77
  78 typedef struct name_database_entry
  79 {
  80   /* And the link to the next entry.  */
  81   struct name_database_entry *next;
  82   /* List of service to be used.  */
  83   service_user *service;
  84   /* Name of the database.  */
  85   char name[0];
  86 } name_database_entry;
  87
  88
  89 typedef struct name_database
  90 {
  91   /* List of all known databases.  */
  92   name_database_entry *entry;
  93   /* List of libraries with service implementation.  */
  94   service_library *library;
  95 } name_database;
  96
  97
  98 /* Interface functions for NSS.  */
  99
 100 /* Get the data structure representing the specified database.
 101    If there is no configuration for this database in the file,
 102    parse a service list from DEFCONFIG and use that.  More
 103    than one function can use the database.  */
 104 int __nss_database_lookup (const char *database, const char *alternative_name,
 105                            const char *defconfig, service_user **ni);
 106
 107
 108 /* Put first function with name FCT_NAME for SERVICE in FCTP.  The
 109    position is remembered in NI.  The function returns a value < 0 if
 110    an error occurred or no such function exists.  */
 111 int __nss_lookup (service_user **ni, const char *fct_name, void **fctp);
 112
 113 /* Determine the next step in the lookup process according to the
 114    result STATUS of the call to the last function returned by
 115    `__nss_lookup' or `__nss_next'.  NI specifies the last function
 116    examined.  The function return a value > 0 if the process should
 117    stop with the last result of the last function call to be the
 118    result of the entire lookup.  The returned value is 0 if there is
 119    another function to use and < 0 if an error occurred.
 120
 121    If ALL_VALUES is nonzero, the return value will not be > 0 as long as
 122    there is a possibility the lookup process can ever use following
 123    services.  In other words, only if all four lookup results have
 124    the action RETURN associated the lookup process stops before the
 125    natural end.  */
 126 int __nss_next (service_user **ni, const char *fct_name, void **fctp,
 127                 int status, int all_values);
 128
 129 /* Search for the service described in NI for a function named FCT_NAME
 130    and return a pointer to this function if successful.  */
 131 void *__nss_lookup_function (service_user *ni, const char *fct_name);
 132
 133 #endif  /* nsswitch.h */