1 | /* Copyright (C) 1999-2022 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include "ifreq.h" |
19 | |
20 | |
21 | void |
22 | __ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd) |
23 | { |
24 | int fd = sockfd; |
25 | struct ifconf ifc; |
26 | int rq_len; |
27 | int nifs; |
28 | # define RQ_IFS 4 |
29 | |
30 | if (fd < 0) |
31 | fd = __opensock (); |
32 | if (fd < 0) |
33 | { |
34 | *num_ifs = 0; |
35 | *ifreqs = NULL; |
36 | return; |
37 | } |
38 | |
39 | ifc.ifc_buf = NULL; |
40 | rq_len = RQ_IFS * sizeof (struct ifreq) / 2; /* Doubled in the loop. */ |
41 | do |
42 | { |
43 | ifc.ifc_len = rq_len *= 2; |
44 | void *newp = realloc (ptr: ifc.ifc_buf, size: ifc.ifc_len); |
45 | if (newp == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0) |
46 | { |
47 | free (ptr: ifc.ifc_buf); |
48 | |
49 | if (fd != sockfd) |
50 | __close (fd); |
51 | *num_ifs = 0; |
52 | *ifreqs = NULL; |
53 | return; |
54 | } |
55 | ifc.ifc_buf = newp; |
56 | } |
57 | while (rq_len < sizeof (struct ifreq) + ifc.ifc_len); |
58 | |
59 | if (fd != sockfd) |
60 | __close (fd); |
61 | |
62 | #ifdef _HAVE_SA_LEN |
63 | struct ifreq *ifr = *ifreqs; |
64 | nifs = 0; |
65 | while ((char *) ifr < ifc.ifc_buf + ifc.ifc_len) |
66 | { |
67 | ++nifs; |
68 | ifr = __if_nextreq (ifr); |
69 | if (ifr == NULL) |
70 | break; |
71 | } |
72 | #else |
73 | nifs = ifc.ifc_len / sizeof (struct ifreq); |
74 | #endif |
75 | |
76 | *num_ifs = nifs; |
77 | *ifreqs = realloc (ptr: ifc.ifc_buf, size: nifs * sizeof (struct ifreq)); |
78 | } |
79 | |