74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/* Copyright (C) 1999-2022 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 "ifreq.h"
|
|
|
|
|
|
void
|
|
__ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
|
|
{
|
|
int fd = sockfd;
|
|
struct ifconf ifc;
|
|
int rq_len;
|
|
int nifs;
|
|
# define RQ_IFS 4
|
|
|
|
if (fd < 0)
|
|
fd = __opensock ();
|
|
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. */
|
|
ifc.ifc_buf = NULL;
|
|
ifc.ifc_len = 0;
|
|
if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0 || ifc.ifc_len == 0)
|
|
rq_len = RQ_IFS * sizeof (struct ifreq);
|
|
else
|
|
rq_len = ifc.ifc_len;
|
|
|
|
/* Read all the interfaces out of the kernel. */
|
|
ifc.ifc_len = rq_len;
|
|
void *newp = realloc (ifc.ifc_buf, ifc.ifc_len);
|
|
if (newp == NULL
|
|
|| (ifc.ifc_buf = newp, __ioctl (fd, SIOCGIFCONF, &ifc)) < 0)
|
|
{
|
|
free (ifc.ifc_buf);
|
|
|
|
if (fd != sockfd)
|
|
__close (fd);
|
|
|
|
*num_ifs = 0;
|
|
*ifreqs = NULL;
|
|
return;
|
|
}
|
|
|
|
nifs = ifc.ifc_len / sizeof (struct ifreq);
|
|
|
|
if (fd != sockfd)
|
|
__close (fd);
|
|
|
|
*num_ifs = nifs;
|
|
*ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq));
|
|
}
|