| 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 | /* Variable to signal whether SIOCGIFCONF is not available. */ |
|---|
| 23 | #if __ASSUME_SIOCGIFNAME == 0 || 1 |
|---|
| 24 | static int old_siocgifconf; |
|---|
| 25 | #else |
|---|
| 26 | # define old_siocgifconf 0 |
|---|
| 27 | #endif |
|---|
| 28 | |
|---|
| 29 | |
|---|
| 30 | void |
|---|
| 31 | __ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd) |
|---|
| 32 | { |
|---|
| 33 | int fd = sockfd; |
|---|
| 34 | struct ifconf ifc; |
|---|
| 35 | int rq_len; |
|---|
| 36 | int nifs; |
|---|
| 37 | # define RQ_IFS 4 |
|---|
| 38 | |
|---|
| 39 | if (fd < 0) |
|---|
| 40 | fd = __opensock (); |
|---|
| 41 | if (fd < 0) |
|---|
| 42 | { |
|---|
| 43 | *num_ifs = 0; |
|---|
| 44 | *ifreqs = NULL; |
|---|
| 45 | return; |
|---|
| 46 | } |
|---|
| 47 | |
|---|
| 48 | ifc.ifc_buf = NULL; |
|---|
| 49 | |
|---|
| 50 | /* We may be able to get the needed buffer size directly, rather than |
|---|
| 51 | guessing. */ |
|---|
| 52 | if (! old_siocgifconf) |
|---|
| 53 | { |
|---|
| 54 | ifc.ifc_buf = NULL; |
|---|
| 55 | ifc.ifc_len = 0; |
|---|
| 56 | if (ioctl (fd, SIOCGIFCONF, &ifc) < 0 || ifc.ifc_len == 0) |
|---|
| 57 | { |
|---|
| 58 | # if __ASSUME_SIOCGIFNAME == 0 |
|---|
| 59 | old_siocgifconf = 1; |
|---|
| 60 | # endif |
|---|
| 61 | rq_len = RQ_IFS * sizeof (struct ifreq); |
|---|
| 62 | } |
|---|
| 63 | else |
|---|
| 64 | rq_len = ifc.ifc_len; |
|---|
| 65 | } |
|---|
| 66 | else |
|---|
| 67 | rq_len = RQ_IFS * sizeof (struct ifreq); |
|---|
| 68 | |
|---|
| 69 | /* Read all the interfaces out of the kernel. */ |
|---|
| 70 | while (1) |
|---|
| 71 | { |
|---|
| 72 | ifc.ifc_len = rq_len; |
|---|
| 73 | void *newp = realloc (ifc.ifc_buf, ifc.ifc_len); |
|---|
| 74 | if (newp == NULL |
|---|
| 75 | || (ifc.ifc_buf = newp, ioctl (fd, SIOCGIFCONF, &ifc)) < 0) |
|---|
| 76 | { |
|---|
| 77 | free (ifc.ifc_buf); |
|---|
| 78 | |
|---|
| 79 | if (fd != sockfd) |
|---|
| 80 | close (fd); |
|---|
| 81 | |
|---|
| 82 | *num_ifs = 0; |
|---|
| 83 | *ifreqs = NULL; |
|---|
| 84 | return; |
|---|
| 85 | } |
|---|
| 86 | |
|---|
| 87 | if (!old_siocgifconf || ifc.ifc_len < rq_len) |
|---|
| 88 | break; |
|---|
| 89 | |
|---|
| 90 | rq_len *= 2; |
|---|
| 91 | } |
|---|
| 92 | |
|---|
| 93 | nifs = ifc.ifc_len / sizeof (struct ifreq); |
|---|
| 94 | |
|---|
| 95 | if (fd != sockfd) |
|---|
| 96 | close (fd); |
|---|
| 97 | |
|---|
| 98 | *num_ifs = nifs; |
|---|
| 99 | *ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq)); |
|---|
| 100 | } |
|---|
