1: /* Copyright (C) 1999, 2002, 2003, 2004 Free Software Foundation, Inc.
    2:    This file is part of the GNU C Library.
    3:    Contributed by Andreas Jaeger <aj@suse.de>.
    4: 
    5:    The GNU C Library is free software; you can redistribute it and/or
    6:    modify it under the terms of the GNU Lesser General Public
    7:    License as published by the Free Software Foundation; either
    8:    version 2.1 of the License, or (at your option) any later version.
    9: 
   10:    The GNU C Library is distributed in the hope that it will be useful,
   11:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   12:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   13:    Lesser General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU Lesser General Public
   16:    License along with the GNU C Library; if not, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    02111-1307 USA.  */
   19: 
   20: #include "ifreq.h"
   21: 
   22: 
   23: void
   24: __ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
   25: {
   26:   int fd = sockfd;
   27:   struct ifconf ifc;
   28:   int rq_len;
   29:   int nifs;
   30: # define RQ_IFS 4
   31: 
   32:   if (fd < 0)
   33:     fd = __opensock ();
   34:   if (fd < 0)
   35:     {
   36:       *num_ifs = 0;
   37:       *ifreqs = NULL;
   38:       return;
   39:     }
   40: 
   41:   ifc.ifc_buf = NULL;
   42:   rq_len = RQ_IFS * sizeof (struct ifreq) / 2; /* Doubled in the loop.  */
   43:   do
   44:     {
   45:       ifc.ifc_len = rq_len *= 2;
   46:       void *newp = realloc (ifc.ifc_buf, ifc.ifc_len);
   47:       if (newp == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0)
   48:         {
   49:           free (ifc.ifc_buf);
   50: 
   51:           if (fd != sockfd)
   52:             __close (fd);
   53:           *num_ifs = 0;
   54:           *ifreqs = NULL;
   55:           return;
   56:         }
   57:       ifc.ifc_buf = newp;
   58:     }
   59:   while (rq_len < sizeof (struct ifreq) + ifc.ifc_len);
   60: 
   61:   if (fd != sockfd)
   62:     __close (fd);
   63: 
   64: #ifdef _HAVE_SA_LEN
   65:   struct ifreq *ifr = *ifreqs;
   66:   nifs = 0;
   67:   while ((char *) ifr < ifc.ifc_buf + ifc.ifc_len)
   68:     {
   69:       ++nifs;
   70:       ifr = __if_nextreq (ifr);
   71:       if (ifr == NULL)
   72:         break;
   73:     }
   74: #else
   75:   nifs = ifc.ifc_len / sizeof (struct ifreq);
   76: #endif
   77: 
   78:   *num_ifs = nifs;
   79:   *ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq));
   80: }