1/* Copyright (C) 1996-2017 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#include <assert.h>
19#include <errno.h>
20#include <libc-lock.h>
21#include <stdlib.h>
22#include <resolv.h>
23
24#include "nsswitch.h"
25
26/*******************************************************************\
27|* Here we assume several symbols to be defined: *|
28|* *|
29|* LOOKUP_TYPE - the return type of the function *|
30|* *|
31|* FUNCTION_NAME - name of the non-reentrant function *|
32|* *|
33|* DATABASE_NAME - name of the database the function accesses *|
34|* (e.g., host, services, ...) *|
35|* *|
36|* ADD_PARAMS - additional parameter, can vary in number *|
37|* *|
38|* ADD_VARIABLES - names of additional parameter *|
39|* *|
40|* BUFLEN - length of buffer allocated for the non *|
41|* reentrant version *|
42|* *|
43|* Optionally the following vars can be defined: *|
44|* *|
45|* NEED_H_ERRNO - an extra parameter will be passed to point to *|
46|* the global `h_errno' variable. *|
47|* *|
48\*******************************************************************/
49
50/* To make the real sources a bit prettier. */
51#define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
52#define APPEND_R(name) APPEND_R1 (name)
53#define APPEND_R1(name) name##_r
54#define INTERNAL(name) INTERNAL1 (name)
55#define INTERNAL1(name) __##name
56
57/* Sometimes we need to store error codes in the `h_errno' variable. */
58#ifdef NEED_H_ERRNO
59# define H_ERRNO_PARM , int *h_errnop
60# define H_ERRNO_VAR , &h_errno_tmp
61# define H_ERRNO_VAR_P &h_errno_tmp
62#else
63# define H_ERRNO_PARM
64# define H_ERRNO_VAR
65# define H_ERRNO_VAR_P NULL
66#endif
67
68#ifdef HAVE_AF
69# define AF_VAL af
70#else
71# define AF_VAL AF_INET
72#endif
73
74/* Prototype for reentrant version we use here. */
75extern int INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf,
76 char *buffer, size_t buflen,
77 LOOKUP_TYPE **result H_ERRNO_PARM);
78
79/* We need to protect the dynamic buffer handling. */
80__libc_lock_define_initialized (static, lock);
81
82/* This points to the static buffer used. */
83libc_freeres_ptr (static char *buffer);
84
85
86LOOKUP_TYPE *
87FUNCTION_NAME (ADD_PARAMS)
88{
89 static size_t buffer_size;
90 static LOOKUP_TYPE resbuf;
91 LOOKUP_TYPE *result;
92#ifdef NEED_H_ERRNO
93 int h_errno_tmp = 0;
94#endif
95
96 /* Get lock. */
97 __libc_lock_lock (lock);
98
99 if (buffer == NULL)
100 {
101 buffer_size = BUFLEN;
102 buffer = (char *) malloc (buffer_size);
103 }
104
105#ifdef HANDLE_DIGITS_DOTS
106 if (buffer != NULL)
107 {
108 if (__nss_hostname_digits_dots (name, &resbuf, &buffer,
109 &buffer_size, 0, &result, NULL, AF_VAL,
110 H_ERRNO_VAR_P))
111 goto done;
112 }
113#endif
114
115 while (buffer != NULL
116 && (INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, &resbuf, buffer,
117 buffer_size, &result H_ERRNO_VAR)
118 == ERANGE)
119#ifdef NEED_H_ERRNO
120 && h_errno_tmp == NETDB_INTERNAL
121#endif
122 )
123 {
124 char *new_buf;
125 buffer_size *= 2;
126 new_buf = (char *) realloc (buffer, buffer_size);
127 if (new_buf == NULL)
128 {
129 /* We are out of memory. Free the current buffer so that the
130 process gets a chance for a normal termination. */
131 free (buffer);
132 __set_errno (ENOMEM);
133 }
134 buffer = new_buf;
135 }
136
137 if (buffer == NULL)
138 result = NULL;
139
140#ifdef HANDLE_DIGITS_DOTS
141done:
142#endif
143 /* Release lock. */
144 __libc_lock_unlock (lock);
145
146#ifdef NEED_H_ERRNO
147 if (h_errno_tmp != 0)
148 __set_h_errno (h_errno_tmp);
149#endif
150
151 return result;
152}
153
154nss_interface_function (FUNCTION_NAME)
155