nss/nsswitch.h

   1 /* Copyright (C) 1996-1999,2001,2002,2003,2004,2007,2010,2011
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  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 #include <stdbool.h>
  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   /* And the link to the next entry.  */
  64   struct service_user *next;
  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   void *known;
  71   /* Name of the service (`files', `dns', `nis', ...).  */
  72   char name[0];
  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   /* And the link to the next entry.  */
  82   struct name_database_entry *next;
  83   /* List of service to be used.  */
  84   service_user *service;
  85   /* Name of the database.  */
  86   char name[0];
  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 /* Indices into DATABASES in nsswitch.c and __NSS_DATABASE_CUSTOM.  */
 100 enum
 101   {
 102 #define DEFINE_DATABASE(arg) NSS_DBSIDX_##arg,
 103 #include "databases.def"
 104 #undef DEFINE_DATABASE
 105     NSS_DBSIDX_max
 106   };
 107
 108 /* Flags whether custom rules for database is set.  */
 109 extern bool __nss_database_custom[NSS_DBSIDX_max];
 110
 111
 112 /* Interface functions for NSS.  */
 113
 114 /* Get the data structure representing the specified database.
 115    If there is no configuration for this database in the file,
 116    parse a service list from DEFCONFIG and use that.  More
 117    than one function can use the database.  */
 118 extern int __nss_database_lookup (const char *database,
 119                                   const char *alternative_name,
 120                                   const char *defconfig, service_user **ni);
 121 libc_hidden_proto (__nss_database_lookup)
 122
 123 /* Put first function with name FCT_NAME for SERVICE in FCTP.  The
 124    position is remembered in NI.  The function returns a value < 0 if
 125    an error occurred or no such function exists.  */
 126 extern int __nss_lookup (service_user **ni, const char *fct_name,
 127                          const char *fct2_name, void **fctp);
 128 libc_hidden_proto (__nss_lookup)
 129
 130 /* Determine the next step in the lookup process according to the
 131    result STATUS of the call to the last function returned by
 132    `__nss_lookup' or `__nss_next'.  NI specifies the last function
 133    examined.  The function return a value > 0 if the process should
 134    stop with the last result of the last function call to be the
 135    result of the entire lookup.  The returned value is 0 if there is
 136    another function to use and < 0 if an error occurred.
 137
 138    If ALL_VALUES is nonzero, the return value will not be > 0 as long as
 139    there is a possibility the lookup process can ever use following
 140    services.  In other words, only if all four lookup results have
 141    the action RETURN associated the lookup process stops before the
 142    natural end.  */
 143 extern int __nss_next2 (service_user **ni, const char *fct_name,
 144                         const char *fct2_name, void **fctp, int status,
 145                         int all_values) attribute_hidden;
 146 libc_hidden_proto (__nss_next2)
 147 extern int __nss_next (service_user **ni, const char *fct_name, void **fctp,
 148                        int status, int all_values);
 149
 150 /* Search for the service described in NI for a function named FCT_NAME
 151    and return a pointer to this function if successful.  */
 152 extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
 153 libc_hidden_proto (__nss_lookup_function)
 154
 155
 156 /* Called by NSCD to disable recursive calls and enable special handling
 157    when used in nscd.  */
 158 struct traced_file;
 159 extern void __nss_disable_nscd (void (*) (size_t, struct traced_file *));
 160
 161
 162 typedef int (*db_lookup_function) (service_user **, const char *, const char *,
 163                                    void **)
 164      internal_function;
 165 typedef enum nss_status (*setent_function) (int);
 166 typedef enum nss_status (*endent_function) (void);
 167 typedef enum nss_status (*getent_function) (void *, char *, size_t,
 168                                             int *, int *);
 169 typedef int (*getent_r_function) (void *, char *, size_t,
 170                                   void **result, int *);
 171
 172 extern void __nss_setent (const char *func_name,
 173                           db_lookup_function lookup_fct,
 174                           service_user **nip, service_user **startp,
 175                           service_user **last_nip, int stayon,
 176                           int *stayon_tmp, int res);
 177 extern void __nss_endent (const char *func_name,
 178                           db_lookup_function lookup_fct,
 179                           service_user **nip, service_user **startp,
 180                           service_user **last_nip, int res);
 181 extern int __nss_getent_r (const char *getent_func_name,
 182                            const char *setent_func_name,
 183                            db_lookup_function lookup_fct,
 184                            service_user **nip, service_user **startp,
 185                            service_user **last_nip, int *stayon_tmp,
 186                            int res,
 187                            void *resbuf, char *buffer, size_t buflen,
 188                            void **result, int *h_errnop);
 189 extern void *__nss_getent (getent_r_function func,
 190                            void **resbuf, char **buffer, size_t buflen,
 191                            size_t *buffer_size, int *h_errnop);
 192 struct hostent;
 193 extern int __nss_hostname_digits_dots (const char *name,
 194                                        struct hostent *resbuf, char **buffer,
 195                                        size_t *buffer_size, size_t buflen,
 196                                        struct hostent **result,
 197                                        enum nss_status *status, int af,
 198                                        int *h_errnop);
 199 libc_hidden_proto (__nss_hostname_digits_dots)
 200
 201 #endif  /* nsswitch.h */