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/* Copyright (C) 1996-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <libc-lock.h>
#include <stdlib.h>
#include <resolv.h>
#include "nsswitch.h"
/*******************************************************************\
|* Here we assume several symbols to be defined: *|
|* *|
|* LOOKUP_TYPE - the return type of the function *|
|* *|
|* FUNCTION_NAME - name of the non-reentrant function *|
|* *|
|* DATABASE_NAME - name of the database the function accesses *|
|* (e.g., host, services, ...) *|
|* *|
|* ADD_PARAMS - additional parameter, can vary in number *|
|* *|
|* ADD_VARIABLES - names of additional parameter *|
|* *|
|* BUFLEN - length of buffer allocated for the non *|
|* reentrant version *|
|* *|
|* Optionally the following vars can be defined: *|
|* *|
|* NEED_H_ERRNO - an extra parameter will be passed to point to *|
|* the global `h_errno' variable. *|
|* *|
\*******************************************************************/
#ifdef HANDLE_DIGITS_DOTS
# include <resolv/resolv_context.h>
#endif
/* To make the real sources a bit prettier. */
#define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
#define APPEND_R(name) APPEND_R1 (name)
#define APPEND_R1(name) name##_r
#define INTERNAL(name) INTERNAL1 (name)
#define INTERNAL1(name) __##name
/* Sometimes we need to store error codes in the `h_errno' variable. */
#ifdef NEED_H_ERRNO
# define H_ERRNO_PARM , int *h_errnop
# define H_ERRNO_VAR , &h_errno_tmp
# define H_ERRNO_VAR_P &h_errno_tmp
#else
# define H_ERRNO_PARM
# define H_ERRNO_VAR
# define H_ERRNO_VAR_P NULL
#endif
#ifdef HAVE_AF
# define AF_VAL af
#else
# define AF_VAL AF_INET
#endif
/* Prototype for reentrant version we use here. */
extern int INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf,
char *buffer, size_t buflen,
LOOKUP_TYPE **result H_ERRNO_PARM)
attribute_hidden;
/* We need to protect the dynamic buffer handling. */
__libc_lock_define_initialized (static, lock);
/* This points to the static buffer used. */
libc_freeres_ptr (static char *buffer);
LOOKUP_TYPE *
FUNCTION_NAME (ADD_PARAMS)
{
static size_t buffer_size;
static LOOKUP_TYPE resbuf;
LOOKUP_TYPE *result;
#ifdef NEED_H_ERRNO
int h_errno_tmp = 0;
#endif
#ifdef HANDLE_DIGITS_DOTS
/* Wrap both __nss_hostname_digits_dots and the actual lookup
function call in the same context. */
struct resolv_context *res_ctx = __resolv_context_get ();
if (res_ctx == NULL)
{
# if NEED_H_ERRNO
__set_h_errno (NETDB_INTERNAL);
# endif
return NULL;
}
#endif
/* Get lock. */
__libc_lock_lock (lock);
if (buffer == NULL)
{
buffer_size = BUFLEN;
buffer = (char *) malloc (buffer_size);
}
#ifdef HANDLE_DIGITS_DOTS
if (buffer != NULL)
{
if (__nss_hostname_digits_dots_context
(res_ctx, name, &resbuf, &buffer, &buffer_size, 0, &result, NULL,
AF_VAL, H_ERRNO_VAR_P))
goto done;
}
#endif
while (buffer != NULL
&& (INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, &resbuf, buffer,
buffer_size, &result H_ERRNO_VAR)
== ERANGE)
#ifdef NEED_H_ERRNO
&& h_errno_tmp == NETDB_INTERNAL
#endif
)
{
char *new_buf;
buffer_size *= 2;
new_buf = (char *) realloc (buffer, buffer_size);
if (new_buf == NULL)
{
/* We are out of memory. Free the current buffer so that the
process gets a chance for a normal termination. */
free (buffer);
__set_errno (ENOMEM);
}
buffer = new_buf;
}
if (buffer == NULL)
result = NULL;
#ifdef HANDLE_DIGITS_DOTS
done:
#endif
/* Release lock. */
__libc_lock_unlock (lock);
#ifdef HANDLE_DIGITS_DOTS
__resolv_context_put (res_ctx);
#endif
#ifdef NEED_H_ERRNO
if (h_errno_tmp != 0)
__set_h_errno (h_errno_tmp);
#endif
return result;
}
nss_interface_function (FUNCTION_NAME)
|
