98 lines
2.9 KiB
C
98 lines
2.9 KiB
C
/* Convert Inet number to ASCII representation.
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Copyright (C) 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <stdio.h>
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#include <stdlib.h>
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#include <arpa/inet.h>
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#include <libc-lock.h>
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/* The interface of this function is completely stupid, it requires a
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static buffer. We relax this a bit in that we allow at least one
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buffer for each thread. */
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__libc_lock_define_initialized (static, lock);
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/* This is the key for the thread specific memory. */
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static __libc_key_t key;
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/* Destructor for the thread-specific data. */
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static void free_key_mem (void *mem);
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char *
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inet_ntoa (struct in_addr in)
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{
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static char static_buf[18];
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static int initialized = 0;
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char *buffer = NULL;
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unsigned char *bytes;
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/* If we have not yet initialized the buffer do it now. */
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if (!initialized)
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{
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/* Make sure there is only one process doing the initialization. */
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__libc_lock_lock (lock);
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if (!initialized)
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{
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if (__libc_key_create (&key, free_key_mem))
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/* Creating the key failed. This either means we run
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have only a single-threaded application or something
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really went wrong. In any case use a static buffer
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which is better than nothing. */
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buffer = static_buf;
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}
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__libc_lock_unlock (lock);
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}
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if (buffer == NULL)
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{
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/* We don't use the static buffer and so we have a key. Use it
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to get the thread-specific buffer. */
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buffer = __libc_getspecific (key);
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if (buffer == NULL)
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{
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/* No buffer allocated so far. */
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buffer = malloc (18);
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if (buffer == NULL)
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/* No more memory available. We use the static buffer. */
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buffer = static_buf;
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else
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__libc_setspecific (key, buffer);
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}
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}
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bytes = (unsigned char *) ∈
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snprintf (buffer, 18, "%d.%d.%d.%d", bytes[0], bytes[1], bytes[2], bytes[3]);
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return buffer;
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}
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static void
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free_key_mem (void *mem)
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{
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free (mem);
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/* And we must set the data to NULL so that the destructor is not
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called again. */
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__libc_setspecific (key, NULL);
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}
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