diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/ifreq.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/ifreq.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/ifreq.c b/sysdeps/unix/sysv/linux/ifreq.c new file mode 100644 index 0000000000..ad408df070 --- /dev/null +++ b/sysdeps/unix/sysv/linux/ifreq.c @@ -0,0 +1,93 @@ +/* Copyright (C) 1999, 2002, 2003 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" + + +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; + 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); + + 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)); +} |