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2eecc8af | 1 | /* Check recvmsg results for netlink sockets. |
dff8da6b | 2 | Copyright (C) 2015-2024 Free Software Foundation, Inc. |
2eecc8af FW |
3 | This file is part of the GNU C Library. |
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, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
2eecc8af FW |
18 | |
19 | #include <errno.h> | |
20 | #include <fcntl.h> | |
21 | #include <stdio.h> | |
01bd6251 | 22 | #include <stdbool.h> |
2eecc8af FW |
23 | #include <sys/socket.h> |
24 | ||
25 | #include "netlinkaccess.h" | |
26 | ||
27 | static int | |
28 | get_address_family (int fd) | |
29 | { | |
30 | struct sockaddr_storage sa; | |
31 | socklen_t sa_len = sizeof (sa); | |
32 | if (__getsockname (fd, (struct sockaddr *) &sa, &sa_len) < 0) | |
33 | return -1; | |
34 | /* Check that the socket family number is preserved despite in-band | |
35 | signaling. */ | |
36 | _Static_assert (sizeof (sa.ss_family) < sizeof (int), "address family size"); | |
37 | _Static_assert (0 < (__typeof__ (sa.ss_family)) -1, | |
38 | "address family unsigned"); | |
39 | return sa.ss_family; | |
40 | } | |
41 | ||
42 | void | |
2eecc8af FW |
43 | __netlink_assert_response (int fd, ssize_t result) |
44 | { | |
45 | if (result < 0) | |
46 | { | |
47 | /* Check if the error is unexpected. */ | |
48 | bool terminate = false; | |
49 | int error_code = errno; | |
50 | int family = get_address_family (fd); | |
51 | if (family != AF_NETLINK) | |
52 | /* If the address family does not match (or getsockname | |
53 | failed), report the original error. */ | |
54 | terminate = true; | |
55 | else if (error_code == EBADF | |
56 | || error_code == ENOTCONN | |
57 | || error_code == ENOTSOCK | |
58 | || error_code == ECONNREFUSED) | |
59 | /* These errors indicate that the descriptor is not a | |
60 | connected socket. */ | |
61 | terminate = true; | |
62 | else if (error_code == EAGAIN || error_code == EWOULDBLOCK) | |
63 | { | |
64 | /* The kernel might return EAGAIN for other reasons than a | |
65 | non-blocking socket. But if the socket is not blocking, | |
66 | it is not ours, so report the error. */ | |
67 | int mode = __fcntl (fd, F_GETFL, 0); | |
68 | if (mode < 0 || (mode & O_NONBLOCK) != 0) | |
69 | terminate = true; | |
70 | } | |
71 | if (terminate) | |
72 | { | |
73 | char message[200]; | |
74 | if (family < 0) | |
75 | __snprintf (message, sizeof (message), | |
a6e8926f | 76 | "Unexpected error %d on netlink descriptor %d.\n", |
2eecc8af FW |
77 | error_code, fd); |
78 | else | |
79 | __snprintf (message, sizeof (message), | |
80 | "Unexpected error %d on netlink descriptor %d" | |
a6e8926f | 81 | " (address family %d).\n", |
2eecc8af FW |
82 | error_code, fd, family); |
83 | __libc_fatal (message); | |
84 | } | |
85 | else | |
d13733c1 | 86 | /* Restore original errno value. */ |
2eecc8af FW |
87 | __set_errno (error_code); |
88 | } | |
89 | else if (result < sizeof (struct nlmsghdr)) | |
90 | { | |
91 | char message[200]; | |
92 | int family = get_address_family (fd); | |
93 | if (family < 0) | |
94 | __snprintf (message, sizeof (message), | |
95 | "Unexpected netlink response of size %zd" | |
36f30c10 | 96 | " on descriptor %d\n", |
2eecc8af FW |
97 | result, fd); |
98 | else | |
99 | __snprintf (message, sizeof (message), | |
100 | "Unexpected netlink response of size %zd" | |
36f30c10 | 101 | " on descriptor %d (address family %d)\n", |
2eecc8af FW |
102 | result, fd, family); |
103 | __libc_fatal (message); | |
104 | } | |
105 | } | |
106 | libc_hidden_def (__netlink_assert_response) |