nss/nsswitch.h

   1 /* Copyright (C) 1996-2015 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 /* Warning for NSS functions, which don't require dlopen if glibc
 111    was built with --enable-static-nss.  */
 112 #ifdef DO_STATIC_NSS
 113 # define nss_interface_function(name)
 114 #else
 115 # define nss_interface_function(name) static_link_warning (name)
 116 #endif
 117
 118
 119 /* Interface functions for NSS.  */
 120
 121 /* Get the data structure representing the specified database.
 122    If there is no configuration for this database in the file,
 123    parse a service list from DEFCONFIG and use that.  More
 124    than one function can use the database.  */
 125 extern int __nss_database_lookup (const char *database,
 126                                   const char *alternative_name,
 127                                   const char *defconfig, service_user **ni);
 128 libc_hidden_proto (__nss_database_lookup)
 129
 130 /* Put first function with name FCT_NAME for SERVICE in FCTP.  The
 131    position is remembered in NI.  The function returns a value < 0 if
 132    an error occurred or no such function exists.  */
 133 extern int __nss_lookup (service_user **ni, const char *fct_name,
 134                          const char *fct2_name, void **fctp);
 135 libc_hidden_proto (__nss_lookup)
 136
 137 /* Determine the next step in the lookup process according to the
 138    result STATUS of the call to the last function returned by
 139    `__nss_lookup' or `__nss_next'.  NI specifies the last function
 140    examined.  The function return a value > 0 if the process should
 141    stop with the last result of the last function call to be the
 142    result of the entire lookup.  The returned value is 0 if there is
 143    another function to use and < 0 if an error occurred.
 144
 145    If ALL_VALUES is nonzero, the return value will not be > 0 as long as
 146    there is a possibility the lookup process can ever use following
 147    services.  In other words, only if all four lookup results have
 148    the action RETURN associated the lookup process stops before the
 149    natural end.  */
 150 extern int __nss_next2 (service_user **ni, const char *fct_name,
 151                         const char *fct2_name, void **fctp, int status,
 152                         int all_values) attribute_hidden;
 153 libc_hidden_proto (__nss_next2)
 154 extern int __nss_next (service_user **ni, const char *fct_name, void **fctp,
 155                        int status, int all_values);
 156
 157 /* Search for the service described in NI for a function named FCT_NAME
 158    and return a pointer to this function if successful.  */
 159 extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
 160 libc_hidden_proto (__nss_lookup_function)
 161
 162
 163 /* Called by NSCD to disable recursive calls and enable special handling
 164    when used in nscd.  */
 165 struct traced_file;
 166 extern void __nss_disable_nscd (void (*) (size_t, struct traced_file *));
 167
 168
 169 typedef int (*db_lookup_function) (service_user **, const char *, const char *,
 170                                    void **)
 171      internal_function;
 172 typedef enum nss_status (*setent_function) (int);
 173 typedef enum nss_status (*endent_function) (void);
 174 typedef enum nss_status (*getent_function) (void *, char *, size_t,
 175                                             int *, int *);
 176 typedef int (*getent_r_function) (void *, char *, size_t,
 177                                   void **result, int *);
 178
 179 extern void __nss_setent (const char *func_name,
 180                           db_lookup_function lookup_fct,
 181                           service_user **nip, service_user **startp,
 182                           service_user **last_nip, int stayon,
 183                           int *stayon_tmp, int res);
 184 extern void __nss_endent (const char *func_name,
 185                           db_lookup_function lookup_fct,
 186                           service_user **nip, service_user **startp,
 187                           service_user **last_nip, int res);
 188 extern int __nss_getent_r (const char *getent_func_name,
 189                            const char *setent_func_name,
 190                            db_lookup_function lookup_fct,
 191                            service_user **nip, service_user **startp,
 192                            service_user **last_nip, int *stayon_tmp,
 193                            int res,
 194                            void *resbuf, char *buffer, size_t buflen,
 195                            void **result, int *h_errnop);
 196 extern void *__nss_getent (getent_r_function func,
 197                            void **resbuf, char **buffer, size_t buflen,
 198                            size_t *buffer_size, int *h_errnop);
 199 struct hostent;
 200 extern int __nss_hostname_digits_dots (const char *name,
 201                                        struct hostent *resbuf, char **buffer,
 202                                        size_t *buffer_size, size_t buflen,
 203                                        struct hostent **result,
 204                                        enum nss_status *status, int af,
 205                                        int *h_errnop);
 206 libc_hidden_proto (__nss_hostname_digits_dots)
 207
 208 /* Maximum number of aliases we allow.  */
 209 #define MAX_NR_ALIASES  48
 210 #define MAX_NR_ADDRS    48
 211
 212 #endif  /* nsswitch.h */