nss/nsswitch.h

   1 /* Copyright (C) 1996-2012 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _NSSWITCH_H
  19 #define _NSSWITCH_H     1
  20
  21 /* This is an *internal* header.  */
  22
  23 #include <arpa/nameser.h>
  24 #include <netinet/in.h>
  25 #include <nss.h>
  26 #include <resolv.h>
  27 #include <search.h>
  28 #include <dlfcn.h>
  29 #include <stdbool.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   void *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 /* Indices into DATABASES in nsswitch.c and __NSS_DATABASE_CUSTOM.  */
  99 enum
 100   {
 101 #define DEFINE_DATABASE(arg) NSS_DBSIDX_##arg,
 102 #include "databases.def"
 103 #undef DEFINE_DATABASE
 104     NSS_DBSIDX_max
 105   };
 106
 107 /* Flags whether custom rules for database is set.  */
 108 extern bool __nss_database_custom[NSS_DBSIDX_max];
 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 extern int __nss_database_lookup (const char *database,
 118                                   const char *alternative_name,
 119                                   const char *defconfig, service_user **ni);
 120 libc_hidden_proto (__nss_database_lookup)
 121
 122 /* Put first function with name FCT_NAME for SERVICE in FCTP.  The
 123    position is remembered in NI.  The function returns a value < 0 if
 124    an error occurred or no such function exists.  */
 125 extern int __nss_lookup (service_user **ni, const char *fct_name,
 126                          const char *fct2_name, void **fctp);
 127 libc_hidden_proto (__nss_lookup)
 128
 129 /* Determine the next step in the lookup process according to the
 130    result STATUS of the call to the last function returned by
 131    `__nss_lookup' or `__nss_next'.  NI specifies the last function
 132    examined.  The function return a value > 0 if the process should
 133    stop with the last result of the last function call to be the
 134    result of the entire lookup.  The returned value is 0 if there is
 135    another function to use and < 0 if an error occurred.
 136
 137    If ALL_VALUES is nonzero, the return value will not be > 0 as long as
 138    there is a possibility the lookup process can ever use following
 139    services.  In other words, only if all four lookup results have
 140    the action RETURN associated the lookup process stops before the
 141    natural end.  */
 142 extern int __nss_next2 (service_user **ni, const char *fct_name,
 143                         const char *fct2_name, void **fctp, int status,
 144                         int all_values) attribute_hidden;
 145 libc_hidden_proto (__nss_next2)
 146 extern int __nss_next (service_user **ni, const char *fct_name, void **fctp,
 147                        int status, int all_values);
 148
 149 /* Search for the service described in NI for a function named FCT_NAME
 150    and return a pointer to this function if successful.  */
 151 extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
 152 libc_hidden_proto (__nss_lookup_function)
 153
 154
 155 /* Called by NSCD to disable recursive calls and enable special handling
 156    when used in nscd.  */
 157 struct traced_file;
 158 extern void __nss_disable_nscd (void (*) (size_t, struct traced_file *));
 159
 160
 161 typedef int (*db_lookup_function) (service_user **, const char *, const char *,
 162                                    void **)
 163      internal_function;
 164 typedef enum nss_status (*setent_function) (int);
 165 typedef enum nss_status (*endent_function) (void);
 166 typedef enum nss_status (*getent_function) (void *, char *, size_t,
 167                                             int *, int *);
 168 typedef int (*getent_r_function) (void *, char *, size_t,
 169                                   void **result, int *);
 170
 171 extern void __nss_setent (const char *func_name,
 172                           db_lookup_function lookup_fct,
 173                           service_user **nip, service_user **startp,
 174                           service_user **last_nip, int stayon,
 175                           int *stayon_tmp, int res);
 176 extern void __nss_endent (const char *func_name,
 177                           db_lookup_function lookup_fct,
 178                           service_user **nip, service_user **startp,
 179                           service_user **last_nip, int res);
 180 extern int __nss_getent_r (const char *getent_func_name,
 181                            const char *setent_func_name,
 182                            db_lookup_function lookup_fct,
 183                            service_user **nip, service_user **startp,
 184                            service_user **last_nip, int *stayon_tmp,
 185                            int res,
 186                            void *resbuf, char *buffer, size_t buflen,
 187                            void **result, int *h_errnop);
 188 extern void *__nss_getent (getent_r_function func,
 189                            void **resbuf, char **buffer, size_t buflen,
 190                            size_t *buffer_size, int *h_errnop);
 191 struct hostent;
 192 extern int __nss_hostname_digits_dots (const char *name,
 193                                        struct hostent *resbuf, char **buffer,
 194                                        size_t *buffer_size, size_t buflen,
 195                                        struct hostent **result,
 196                                        enum nss_status *status, int af,
 197                                        int *h_errnop);
 198 libc_hidden_proto (__nss_hostname_digits_dots)
 199
 200 /* Maximum number of aliases we allow.  */
 201 #define MAX_NR_ALIASES  48
 202 #define MAX_NR_ADDRS    48
 203
 204 #endif  /* nsswitch.h */