1/* Copyright (C) 1996-2020 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 <https://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. */
32typedef enum
33{
34 NSS_ACTION_CONTINUE,
35 NSS_ACTION_RETURN,
36 NSS_ACTION_MERGE
37} lookup_actions;
38
39
40typedef 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. */
54typedef struct
55{
56 const char *fct_name;
57 void *fct_ptr;
58} known_function;
59
60
61typedef 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
79typedef 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
90typedef 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#ifdef USE_NSCD
100/* Indices into DATABASES in nsswitch.c and __NSS_DATABASE_CUSTOM. */
101enum
102 {
103# define DEFINE_DATABASE(arg) NSS_DBSIDX_##arg,
104# include "databases.def"
105# undef DEFINE_DATABASE
106 NSS_DBSIDX_max
107 };
108
109/* Flags whether custom rules for database is set. */
110extern bool __nss_database_custom[NSS_DBSIDX_max] attribute_hidden;
111#endif
112
113/* Warning for NSS functions, which don't require dlopen if glibc
114 was built with --enable-static-nss. */
115#ifdef DO_STATIC_NSS
116# define nss_interface_function(name)
117#else
118# define nss_interface_function(name) static_link_warning (name)
119#endif
120
121
122/* Interface functions for NSS. */
123
124/* Get the data structure representing the specified database.
125 If there is no configuration for this database in the file,
126 parse a service list from DEFCONFIG and use that. More
127 than one function can use the database. */
128extern int __nss_database_lookup2 (const char *database,
129 const char *alternative_name,
130 const char *defconfig, service_user **ni);
131libc_hidden_proto (__nss_database_lookup2)
132
133/* Put first function with name FCT_NAME for SERVICE in FCTP. The
134 position is remembered in NI. The function returns a value < 0 if
135 an error occurred or no such function exists. */
136extern int __nss_lookup (service_user **ni, const char *fct_name,
137 const char *fct2_name, void **fctp);
138libc_hidden_proto (__nss_lookup)
139
140/* Determine the next step in the lookup process according to the
141 result STATUS of the call to the last function returned by
142 `__nss_lookup' or `__nss_next'. NI specifies the last function
143 examined. The function return a value > 0 if the process should
144 stop with the last result of the last function call to be the
145 result of the entire lookup. The returned value is 0 if there is
146 another function to use and < 0 if an error occurred.
147
148 If ALL_VALUES is nonzero, the return value will not be > 0 as long as
149 there is a possibility the lookup process can ever use following
150 services. In other words, only if all four lookup results have
151 the action RETURN associated the lookup process stops before the
152 natural end. */
153extern int __nss_next2 (service_user **ni, const char *fct_name,
154 const char *fct2_name, void **fctp, int status,
155 int all_values) attribute_hidden;
156libc_hidden_proto (__nss_next2)
157extern int __nss_next (service_user **ni, const char *fct_name, void **fctp,
158 int status, int all_values);
159
160/* Search for the service described in NI for a function named FCT_NAME
161 and return a pointer to this function if successful. */
162extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
163libc_hidden_proto (__nss_lookup_function)
164
165
166/* Called by NSCD to disable recursive calls and enable special handling
167 when used in nscd. */
168struct traced_file;
169extern void __nss_disable_nscd (void (*) (size_t, struct traced_file *));
170
171
172typedef int (*db_lookup_function) (service_user **, const char *, const char *,
173 void **);
174typedef enum nss_status (*setent_function) (int);
175typedef enum nss_status (*endent_function) (void);
176typedef enum nss_status (*getent_function) (void *, char *, size_t,
177 int *, int *);
178typedef int (*getent_r_function) (void *, char *, size_t,
179 void **result, int *);
180
181extern void __nss_setent (const char *func_name,
182 db_lookup_function lookup_fct,
183 service_user **nip, service_user **startp,
184 service_user **last_nip, int stayon,
185 int *stayon_tmp, int res)
186 attribute_hidden;
187extern void __nss_endent (const char *func_name,
188 db_lookup_function lookup_fct,
189 service_user **nip, service_user **startp,
190 service_user **last_nip, int res)
191 attribute_hidden;
192extern int __nss_getent_r (const char *getent_func_name,
193 const char *setent_func_name,
194 db_lookup_function lookup_fct,
195 service_user **nip, service_user **startp,
196 service_user **last_nip, int *stayon_tmp,
197 int res,
198 void *resbuf, char *buffer, size_t buflen,
199 void **result, int *h_errnop)
200 attribute_hidden;
201extern void *__nss_getent (getent_r_function func,
202 void **resbuf, char **buffer, size_t buflen,
203 size_t *buffer_size, int *h_errnop)
204 attribute_hidden;
205struct resolv_context;
206struct hostent;
207extern int __nss_hostname_digits_dots_context (struct resolv_context *,
208 const char *name,
209 struct hostent *resbuf,
210 char **buffer,
211 size_t *buffer_size,
212 size_t buflen,
213 struct hostent **result,
214 enum nss_status *status, int af,
215 int *h_errnop) attribute_hidden;
216extern int __nss_hostname_digits_dots (const char *name,
217 struct hostent *resbuf, char **buffer,
218 size_t *buffer_size, size_t buflen,
219 struct hostent **result,
220 enum nss_status *status, int af,
221 int *h_errnop);
222libc_hidden_proto (__nss_hostname_digits_dots)
223
224/* Maximum number of aliases we allow. */
225#define MAX_NR_ALIASES 48
226#define MAX_NR_ADDRS 48
227
228/* Prototypes for __nss_*_lookup2 functions. */
229#define DEFINE_DATABASE(arg) \
230 extern service_user *__nss_##arg##_database attribute_hidden; \
231 int __nss_##arg##_lookup2 (service_user **, const char *, \
232 const char *, void **); \
233 libc_hidden_proto (__nss_##arg##_lookup2)
234#include "databases.def"
235#undef DEFINE_DATABASE
236
237#endif /* nsswitch.h */
238