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[glibc.git] / nss / getXXbyYY.c
blobee6f640002bfe9b91cc95755ae8ef880b769ce90
1 /* Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
19 #include <assert.h>
20 #include <errno.h>
21 #include <bits/libc-lock.h>
22 #include <stdlib.h>
23 #include <resolv.h>
25 #include "nsswitch.h"
27 /*******************************************************************\
28 |* Here we assume several symbols to be defined: *|
29 |* *|
30 |* LOOKUP_TYPE - the return type of the function *|
31 |* *|
32 |* FUNCTION_NAME - name of the non-reentrant function *|
33 |* *|
34 |* DATABASE_NAME - name of the database the function accesses *|
35 |* (e.g., host, services, ...) *|
36 |* *|
37 |* ADD_PARAMS - additional parameter, can vary in number *|
38 |* *|
39 |* ADD_VARIABLES - names of additional parameter *|
40 |* *|
41 |* BUFLEN - length of buffer allocated for the non *|
42 |* reentrant version *|
43 |* *|
44 |* Optionally the following vars can be defined: *|
45 |* *|
46 |* NEED_H_ERRNO - an extra parameter will be passed to point to *|
47 |* the global `h_errno' variable. *|
48 |* *|
49 \*******************************************************************/
51 /* To make the real sources a bit prettier. */
52 #define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
53 #define APPEND_R(name) APPEND_R1 (name)
54 #define APPEND_R1(name) name##_r
55 #define INTERNAL(name) INTERNAL1 (name)
56 #define INTERNAL1(name) __##name
58 /* Sometimes we need to store error codes in the `h_errno' variable. */
59 #ifdef NEED_H_ERRNO
60 # define H_ERRNO_PARM , int *h_errnop
61 # define H_ERRNO_VAR , &h_errno_tmp
62 # define H_ERRNO_VAR_P &h_errno_tmp
63 #else
64 # define H_ERRNO_PARM
65 # define H_ERRNO_VAR
66 # define H_ERRNO_VAR_P NULL
67 #endif
69 #ifndef HAVE_TYPE
70 # define TYPE_VAR_P NULL
71 # define FLAGS_VAR 0
72 #endif
74 #ifdef HAVE_AF
75 # define AF_VAR_P &af
76 #else
77 # define AF_VAR_P NULL
78 #endif
80 /* Prototype for reentrant version we use here. */
81 extern int INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf,
82 char *buffer, size_t buflen,
83 LOOKUP_TYPE **result H_ERRNO_PARM);
85 /* We need to protect the dynamic buffer handling. */
86 __libc_lock_define_initialized (static, lock);
88 /* This points to the static buffer used. */
89 static char *buffer;
92 LOOKUP_TYPE *
93 FUNCTION_NAME (ADD_PARAMS)
95 static size_t buffer_size;
96 static LOOKUP_TYPE resbuf;
97 LOOKUP_TYPE *result;
98 int save;
99 #ifdef NEED_H_ERRNO
100 int h_errno_tmp = 0;
101 #endif
103 /* Get lock. */
104 __libc_lock_lock (lock);
106 if (buffer == NULL)
108 buffer_size = BUFLEN;
109 buffer = malloc (buffer_size);
112 #ifdef HANDLE_DIGITS_DOTS
113 if (buffer != NULL)
115 if (__nss_hostname_digits_dots (name, &resbuf, &buffer,
116 &buffer_size,
117 0, &result, NULL, TYPE_VAR_P,
118 FLAGS_VAR, AF_VAR_P,
119 H_ERRNO_VAR_P))
120 goto done;
122 #endif
124 while (buffer != NULL
125 && (INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, &resbuf, buffer,
126 buffer_size, &result H_ERRNO_VAR)
127 == ERANGE)
128 #ifdef NEED_H_ERRNO
129 && h_errno_tmp == NETDB_INTERNAL
130 #endif
133 char *new_buf;
134 buffer_size += BUFLEN;
135 new_buf = realloc (buffer, buffer_size);
136 if (new_buf == NULL)
138 /* We are out of memory. Free the current buffer so that the
139 process gets a chance for a normal termination. */
140 save = errno;
141 free (buffer);
142 __set_errno (save);
144 buffer = new_buf;
147 if (buffer == NULL)
148 result = NULL;
150 #ifdef HANDLE_DIGITS_DOTS
151 done:
152 #endif
153 /* Release lock. Preserve error value. */
154 save = errno;
155 __libc_lock_unlock (lock);
156 __set_errno (save);
158 #ifdef NEED_H_ERRNO
159 if (h_errno_tmp != 0)
160 __set_h_errno (h_errno_tmp);
161 #endif
163 return result;
167 /* Free all resources if necessary. */
168 static void __attribute__ ((unused))
169 free_mem (void)
171 free (buffer);
174 text_set_element (__libc_subfreeres, free_mem);