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/* Copyright (C) 1999 Free Software Foundation, Inc.
Contributed by Andreas Jaeger <aj@suse.de>.
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 <unistd.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include "kernel-features.h"
/* Variable to signal whether SIOCGIFCONF is not available. */
#if __ASSUME_SIOCGIFNAME == 0
static int old_siocgifconf;
#else
# define old_siocgifconf 0
#endif
static inline void
__ifreq (struct ifreq **ifreqs, int *num_ifs)
{
int fd = __opensock ();
struct ifconf ifc;
int rq_len;
int nifs;
# define RQ_IFS 4
if (fd < 0)
{
*num_ifs = 0;
*ifreqs = NULL;
return;
}
ifc.ifc_buf = NULL;
/* We may be able to get the needed buffer size directly, rather than
guessing. */
if (! old_siocgifconf)
{
ifc.ifc_buf = NULL;
ifc.ifc_len = 0;
if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0 || ifc.ifc_len == 0)
{
# if __ASSUME_SIOCGIFNAME == 0
old_siocgifconf = 1;
# endif
rq_len = RQ_IFS * sizeof (struct ifreq);
}
else
rq_len = ifc.ifc_len;
}
else
rq_len = RQ_IFS * sizeof (struct ifreq);
/* Read all the interfaces out of the kernel. */
do
{
ifc.ifc_len = rq_len;
ifc.ifc_buf = realloc (ifc.ifc_buf, ifc.ifc_len);
if (ifc.ifc_buf == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0)
{
if (ifc.ifc_buf)
free (ifc.ifc_buf);
__close (fd);
*num_ifs = 0;
*ifreqs = NULL;
return;
}
rq_len *= 2;
}
while (ifc.ifc_len == rq_len && old_siocgifconf);
nifs = ifc.ifc_len / sizeof (struct ifreq);
__close (fd);
*num_ifs = nifs;
*ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq));
}
static inline void
__if_freereq (struct ifreq *ifreqs)
{
free (ifreqs);
}
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