1 /* Copyright (C) 1996-2023 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 #include <errno.h>
19 #include <libc-lock.h>
20
21 #include "nsswitch.h"
22
23 /*******************************************************************\
24 |* Here we assume several symbols to be defined: *|
25 |* *|
26 |* LOOKUP_TYPE - the return type of the function *|
27 |* *|
28 |* SETFUNC_NAME - name of the non-reentrant setXXXent function *|
29 |* *|
30 |* GETFUNC_NAME - name of the non-reentrant getXXXent function *|
31 |* *|
32 |* ENDFUNC_NAME - name of the non-reentrant endXXXent function *|
33 |* *|
34 |* DATABASE_NAME - name of the database the function accesses *|
35 |* (e.g., host, services, ...) *|
36 |* *|
37 |* Optionally the following vars can be defined: *|
38 |* *|
39 |* STAYOPEN - variable declaration for setXXXent function *|
40 |* *|
41 |* STAYOPEN_VAR - variable name for setXXXent function *|
42 |* *|
43 |* NEED_H_ERRNO - an extra parameter will be passed to point to *|
44 |* the global `h_errno' variable. *|
45 |* *|
46 \*******************************************************************/
47
48 /* To make the real sources a bit prettier. */
49 #define REENTRANT_GETNAME APPEND_R (GETFUNC_NAME)
50 #define APPEND_R(Name) CONCAT2_2 (Name, _r)
51 #define INTERNAL(Name) CONCAT2_2 (__, Name)
52 #define CONCAT2_1(Pre, Post) CONCAT2_2 (Pre, Post)
53 #define CONCAT2_2(Pre, Post) Pre##Post
54 #define NEW(name) NEW1 (name)
55 #define NEW1(name) __new_##name
56
57 #define SETFUNC_NAME_STRING STRINGIZE (SETFUNC_NAME)
58 #define GETFUNC_NAME_STRING STRINGIZE (REENTRANT_GETNAME)
59 #define ENDFUNC_NAME_STRING STRINGIZE (ENDFUNC_NAME)
60 #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME)
61 #define STRINGIZE(Name) STRINGIZE1 (Name)
62 #define STRINGIZE1(Name) #Name
63
64 #ifndef DB_LOOKUP_FCT
65 # define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup2)
66 # define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
67 # define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
68 #endif
69
70 /* Sometimes we need to store error codes in the `h_errno' variable. */
71 #ifdef NEED_H_ERRNO
72 # define H_ERRNO_PARM , int *h_errnop
73 # define H_ERRNO_VAR , &h_errno
74 # define H_ERRNO_VAR_P &h_errno
75 #else
76 # define H_ERRNO_PARM
77 # define H_ERRNO_VAR
78 # define H_ERRNO_VAR_P NULL
79 #endif
80
81 /* Some databases take the `stayopen' flag. */
82 #ifdef STAYOPEN
83 # define STAYOPEN_TMP CONCAT2_1 (STAYOPEN, _tmp)
84 # define STAYOPEN_TMPVAR &CONCAT2_1 (STAYOPEN_VAR, _tmp)
85 #else
86 # define STAYOPEN void
87 # define STAYOPEN_VAR 0
88 # define STAYOPEN_TMPVAR NULL
89 #endif
90
91 #ifndef NEED__RES
92 # define NEED__RES 0
93 #endif
94
95 /* This handle for the NSS data base is shared between all
96 set/get/endXXXent functions. */
97 static nss_action_list nip;
98 /* Remember the last service used since the last call to `endXXent'. */
99 static nss_action_list last_nip;
100 /* Remember the first service_entry across set/get/endent. */
101 static nss_action_list startp;
102
103 #ifdef STAYOPEN_TMP
104 /* We need to remember the last `stayopen' flag given by the user
105 since the `setent' function is only called for the first available
106 service. */
107 static STAYOPEN_TMP;
108 #endif
109
110 /* Protect above variable against multiple uses at the same time. */
111 __libc_lock_define_initialized (static, lock)
112
113 /* The lookup function for the first entry of this service. */
114 extern int DB_LOOKUP_FCT (nss_action_list *nip, const char *name,
115 const char *name2, void **fctp);
116 libc_hidden_proto (DB_LOOKUP_FCT)
117
118 void
119 SETFUNC_NAME (STAYOPEN)
120 {
121 int save;
122
123 __libc_lock_lock (lock);
124 __nss_setent (SETFUNC_NAME_STRING, DB_LOOKUP_FCT, &nip, &startp,
125 &last_nip, STAYOPEN_VAR, STAYOPEN_TMPVAR, NEED__RES);
126
127 save = errno;
128 __libc_lock_unlock (lock);
129 __set_errno (save);
130 }
131
132
133 void
134 ENDFUNC_NAME (void)
135 {
136 int save;
137
138 /* If the service has not been used before do not do anything. */
139 if (startp != NULL)
140 {
141 __libc_lock_lock (lock);
142 __nss_endent (ENDFUNC_NAME_STRING, DB_LOOKUP_FCT, &nip, &startp,
143 &last_nip, NEED__RES);
144 save = errno;
145 __libc_lock_unlock (lock);
146 __set_errno (save);
147 }
148 }
149
150
151 int
152 INTERNAL (REENTRANT_GETNAME) (LOOKUP_TYPE *resbuf, char *buffer, size_t buflen,
153 LOOKUP_TYPE **result H_ERRNO_PARM)
154 {
155 int status;
156 int save;
157
158 __libc_lock_lock (lock);
159 status = __nss_getent_r (GETFUNC_NAME_STRING, SETFUNC_NAME_STRING,
160 DB_LOOKUP_FCT, &nip, &startp, &last_nip,
161 STAYOPEN_TMPVAR, NEED__RES, resbuf, buffer,
162 buflen, (void **) result, H_ERRNO_VAR_P);
163 save = errno;
164 __libc_lock_unlock (lock);
165 __set_errno (save);
166 return status;
167 }
168
169
170 #ifdef NO_COMPAT_NEEDED
171 strong_alias (INTERNAL (REENTRANT_GETNAME), REENTRANT_GETNAME);
172 #else
173 # include <shlib-compat.h>
174 # if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
175 # define OLD(name) OLD1 (name)
176 # define OLD1(name) __old_##name
177
178 int
179 attribute_compat_text_section
180 OLD (REENTRANT_GETNAME) (LOOKUP_TYPE *resbuf, char *buffer, size_t buflen,
181 LOOKUP_TYPE **result H_ERRNO_PARM)
182 {
183 int ret = INTERNAL (REENTRANT_GETNAME) (resbuf, buffer, buflen,
184 result H_ERRNO_VAR);
185
186 if (ret != 0)
187 ret = -1;
188
189 return ret;
190 }
191
192 # define do_symbol_version(real, name, version) \
193 compat_symbol (libc, real, name, version)
194 do_symbol_version (OLD (REENTRANT_GETNAME), REENTRANT_GETNAME, GLIBC_2_0);
195 # endif
196
197 /* As INTERNAL (REENTRANT_GETNAME) may be hidden, we need an alias
198 in between so that the REENTRANT_GETNAME@@GLIBC_2.1.2 is not
199 hidden too. */
200 strong_alias (INTERNAL (REENTRANT_GETNAME), NEW (REENTRANT_GETNAME));
201
202 # define do_default_symbol_version(real, name, version) \
203 versioned_symbol (libc, real, name, version)
204 do_default_symbol_version (NEW (REENTRANT_GETNAME),
205 REENTRANT_GETNAME, GLIBC_2_1_2);
206 #endif
207
208 nss_interface_function (SETFUNC_NAME)
209 nss_interface_function (ENDFUNC_NAME)
210 nss_interface_function (REENTRANT_GETNAME)