nss/nsswitch.h

   1 /* Copyright (C) 1996, 1997, 1998 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 <elf/ldsodefs.h>
  30
  31
  32 /* Actions performed after lookup finished.  */
  33 typedef enum
  34 {
  35   NSS_ACTION_CONTINUE,
  36   NSS_ACTION_RETURN
  37 } lookup_actions;
  38
  39
  40 typedef struct service_library
  41 {
  42   /* Name of service (`files', `dns', `nis', ...).  */
  43   const char *name;
  44   /* Pointer to the loaded shared library.  */
  45   void *lib_handle;
  46   /* And the link to the next entry.  */
  47   struct service_library *next;
  48 } service_library;
  49
  50
  51 /* For mapping a function name to a function pointer.  It is known in
  52    nsswitch.c:nss_lookup_function that a string pointer for the lookup key
  53    is the first member.  */
  54 typedef struct
  55 {
  56   const char *fct_name;
  57   void *fct_ptr;
  58 } known_function;
  59
  60
  61 typedef struct service_user
  62 {
  63   /* Name of the service (`files', `dns', `nis', ...).  */
  64   const char *name;
  65   /* Action according to result.  */
  66   lookup_actions actions[5];
  67   /* Link to the underlying library object.  */
  68   service_library *library;
  69   /* Collection of known functions.  */
  70   struct entry *known;
  71   /* And the link to the next entry.  */
  72   struct service_user *next;
  73 } service_user;
  74
  75 /* To access the action based on the status value use this macro.  */
  76 #define nss_next_action(ni, status) ((ni)->actions[2 + status])
  77
  78
  79 typedef struct name_database_entry
  80 {
  81   /* Name of the database.  */
  82   const char *name;
  83   /* List of service to be used.  */
  84   service_user *service;
  85   /* And the link to the next entry.  */
  86   struct name_database_entry *next;
  87 } name_database_entry;
  88
  89
  90 typedef struct name_database
  91 {
  92   /* List of all known databases.  */
  93   name_database_entry *entry;
  94   /* List of libraries with service implementation.  */
  95   service_library *library;
  96 } name_database;
  97
  98
  99 /* Interface functions for NSS.  */
 100
 101 /* Get the data structure representing the specified database.
 102    If there is no configuration for this database in the file,
 103    parse a service list from DEFCONFIG and use that.  More
 104    than one function can use the database.  */
 105 int __nss_database_lookup (const char *database, const char *alternative_name,
 106                            const char *defconfig, service_user **ni);
 107
 108
 109 /* Put first function with name FCT_NAME for SERVICE in FCTP.  The
 110    position is remembered in NI.  The function returns a value < 0 if
 111    an error occurred or no such function exists.  */
 112 int __nss_lookup (service_user **ni, const char *fct_name, void **fctp);
 113
 114 /* Determine the next step in the lookup process according to the
 115    result STATUS of the call to the last function returned by
 116    `__nss_lookup' or `__nss_next'.  NI specifies the last function
 117    examined.  The function return a value > 0 if the process should
 118    stop with the last result of the last function call to be the
 119    result of the entire lookup.  The returned value is 0 if there is
 120    another function to use and < 0 if an error occurred.
 121
 122    If ALL_VALUES is nonzero, the return value will not be > 0 as long as
 123    there is a possibility the lookup process can ever use following
 124    services.  In other words, only if all four lookup results have
 125    the action RETURN associated the lookup process stops before the
 126    natural end.  */
 127 int __nss_next (service_user **ni, const char *fct_name, void **fctp,
 128                 int status, int all_values);
 129
 130 /* Search for the service described in NI for a function named FCT_NAME
 131    and return a pointer to this function if successful.  */
 132 void *__nss_lookup_function (service_user *ni, const char *fct_name);
 133
 134 #endif  /* nsswitch.h */