/* Convert Inet number to ASCII representation. Copyright (C) 1997, 1998 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. */ /* This is the key for the thread specific memory. */ static __libc_key_t key; /* If nonzero the key allocation failed and we should better use a static buffer than fail. */ static char local_buf[18]; static char *static_buf; /* Destructor for the thread-specific data. */ static void init (void); static void free_key_mem (void *mem); char * inet_ntoa (struct in_addr in) { __libc_once_define (static, once); char *buffer; unsigned char *bytes; /* If we have not yet initialized the buffer do it now. */ __libc_once (once, init); if (static_buf != NULL) buffer = static_buf; else { /* 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 = local_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; } /* Initialize buffer. */ static void init (void) { if (__libc_key_create (&key, free_key_mem)) /* Creating the key failed. This means something really went wrong. In any case use a static buffer which is better than nothing. */ static_buf = local_buf; } /* Free the thread specific data, this is done if a thread terminates. */ static void free_key_mem (void *mem) { free (mem); __libc_setspecific (key, NULL); }