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/* Convert Inet number to ASCII representation.
Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <bits/libc-lock.h>
/* The interface of this function is completely stupid, it requires a
static buffer. We relax this a bit in that we allow at least one
buffer for each thread. */
__libc_lock_define_initialized (static, lock);
/* This is the key for the thread specific memory. */
static __libc_key_t key;
/* Destructor for the thread-specific data. */
static void free_key_mem (void *mem);
char *
inet_ntoa (struct in_addr in)
{
static char static_buf[18];
static int initialized = 0;
char *buffer = NULL;
unsigned char *bytes;
/* If we have not yet initialized the buffer do it now. */
if (!initialized)
{
/* Make sure there is only one process doing the initialization. */
__libc_lock_lock (lock);
if (!initialized)
{
if (__libc_key_create (&key, free_key_mem))
/* Creating the key failed. This either means we run
have only a single-threaded application or something
really went wrong. In any case use a static buffer
which is better than nothing. */
buffer = static_buf;
}
__libc_lock_unlock (lock);
}
if (buffer == NULL)
{
/* We don't use the static buffer and so we have a key. Use it
to get the thread-specific buffer. */
buffer = __libc_getspecific (key);
if (buffer == NULL)
{
/* No buffer allocated so far. */
buffer = malloc (18);
if (buffer == NULL)
/* No more memory available. We use the static buffer. */
buffer = static_buf;
else
__libc_setspecific (key, buffer);
}
}
bytes = (unsigned char *) ∈
snprintf (buffer, 18, "%d.%d.%d.%d", bytes[0], bytes[1], bytes[2], bytes[3]);
return buffer;
}
static void
free_key_mem (void *mem)
{
free (mem);
/* And we must set the data to NULL so that the destructor is not
called again. */
__libc_setspecific (key, NULL);
}
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