| /* Copyright (C) 1999,2002,2003,2004,2005,2006 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| 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 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, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| #include "ifreq.h" |
| #include <kernel-features.h> |
| |
| /* Variable to signal whether SIOCGIFCONF is not available. */ |
| #if __ASSUME_SIOCGIFNAME == 0 || 1 |
| static int old_siocgifconf; |
| #else |
| # define old_siocgifconf 0 |
| #endif |
| |
| |
| 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. */ |
| 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. */ |
| while (1) |
| { |
| 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; |
| } |
| |
| if (!old_siocgifconf || ifc.ifc_len < rq_len) |
| break; |
| |
| rq_len *= 2; |
| } |
| |
| nifs = ifc.ifc_len / sizeof (struct ifreq); |
| |
| if (fd != sockfd) |
| __close (fd); |
| |
| *num_ifs = nifs; |
| *ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq)); |
| } |