nss/nsswitch.h

   1 /* Copyright (C) 1996 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
  16 not, 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 <resolv.h>
  27 #include <search.h>
  28
  29
  30 /* Revision number of NSS interface (must be a string).  */
  31 #define NSS_SHLIB_REVISION ".1"
  32
  33
  34 /* Possible results of lookup using a nss_* function.  */
  35 enum nss_status
  36 {
  37   NSS_STATUS_TRYAGAIN = -2,
  38   NSS_STATUS_UNAVAIL,
  39   NSS_STATUS_NOTFOUND,
  40   NSS_STATUS_SUCCESS,
  41 };
  42
  43
  44 /* Actions performed after lookup finished.  */
  45 typedef enum
  46 {
  47   NSS_ACTION_CONTINUE,
  48   NSS_ACTION_RETURN
  49 } lookup_actions;
  50
  51
  52 typedef struct service_library
  53 {
  54   /* Name of service (`files', `dns', `nis', ...).  */
  55   const char *name;
  56   /* Pointer to the loaded shared library.  */
  57   void *lib_handle;
  58   /* And the link to the next entry.  */
  59   struct service_library *next;
  60 } service_library;
  61
  62
  63 /* For mapping a function name to a function pointer.  It is known in
  64    nsswitch.c:nss_lookup_function that a string pointer for the lookup key
  65    is the first member.  */
  66 typedef struct
  67 {
  68   const char *fct_name;
  69   void *fct_ptr;
  70 } known_function;
  71
  72
  73 typedef struct service_user
  74 {
  75   /* Name of the service (`files', `dns', `nis', ...).  */
  76   const char *name;
  77   /* Action according to result.  */
  78   lookup_actions actions[4];
  79   /* Link to the underlying library object.  */
  80   service_library *library;
  81   /* Collection of known functions.  */
  82   struct entry *known;
  83   /* And the link to the next entry.  */
  84   struct service_user *next;
  85 } service_user;
  86
  87 /* To access the action based on the status value use this macro.  */
  88 #define nss_next_action(ni, status) ((ni)->actions[2 + status])
  89
  90
  91 typedef struct name_database_entry
  92 {
  93   /* Name of the database.  */
  94   const char *name;
  95   /* List of service to be used.  */
  96   service_user *service;
  97   /* And the link to the next entry.  */
  98   struct name_database_entry *next;
  99 } name_database_entry;
 100
 101
 102 typedef struct name_database
 103 {
 104   /* List of all known databases.  */
 105   name_database_entry *entry;
 106   /* List of libraries with service implementation.  */
 107   service_library *library;
 108 } name_database;
 109
 110
 111 /* Interface functions for NSS.  */
 112
 113 /* Get the data structure representing the specified database.
 114    If there is no configuration for this database in the file,
 115    parse a service list from DEFCONFIG and use that.  More
 116    than one function can use the database.  */
 117 int __nss_database_lookup (const char *database, const char *defconfig,
 118                            service_user **ni);
 119
 120
 121 /* Put first function with name FCT_NAME for SERVICE in FCTP.  The
 122    position is remembered in NI.  The function returns a value < 0 if
 123    an error occured or no such function exists.  */
 124 int __nss_lookup (service_user **ni, const char *fct_name, void **fctp);
 125
 126 /* Determine the next step in the lookup process according to the
 127    result STATUS of the call to the last function returned by
 128    `__nss_lookup' or `__nss_next'.  NI specifies the last function
 129    examined.  The function return a value > 0 if the process should
 130    stop with the last result of the last function call to be the
 131    result of the entire lookup.  The returned valie is 0 if there is
 132    another function to use and < 0 if an error occured.
 133
 134    If ALL_VALUES is nonzero, the return value will not be > 0 as long as
 135    there is a possibility the lookup process can ever use following
 136    services.  In other words, only if all four lookup results have
 137    the action RETURN associated the lookup process stops before the
 138    natural end.  */
 139 int __nss_next (service_user **ni, const char *fct_name, void **fctp,
 140                 int status, int all_values);
 141
 142
 143 #endif  /* nsswitch.h */