| /* Check recvmsg results for netlink sockets. |
| Copyright (C) 2015-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stdio.h> |
| #include <sys/socket.h> |
| |
| #include "netlinkaccess.h" |
| |
| static int |
| get_address_family (int fd) |
| { |
| struct sockaddr_storage sa; |
| socklen_t sa_len = sizeof (sa); |
| if (__getsockname (fd, (struct sockaddr *) &sa, &sa_len) < 0) |
| return -1; |
| /* Check that the socket family number is preserved despite in-band |
| signaling. */ |
| _Static_assert (sizeof (sa.ss_family) < sizeof (int), "address family size"); |
| _Static_assert (0 < (__typeof__ (sa.ss_family)) -1, |
| "address family unsigned"); |
| return sa.ss_family; |
| } |
| |
| void |
| __netlink_assert_response (int fd, ssize_t result) |
| { |
| if (result < 0) |
| { |
| /* Check if the error is unexpected. */ |
| bool terminate = false; |
| int error_code = errno; |
| int family = get_address_family (fd); |
| if (family != AF_NETLINK) |
| /* If the address family does not match (or getsockname |
| failed), report the original error. */ |
| terminate = true; |
| else if (error_code == EBADF |
| || error_code == ENOTCONN |
| || error_code == ENOTSOCK |
| || error_code == ECONNREFUSED) |
| /* These errors indicate that the descriptor is not a |
| connected socket. */ |
| terminate = true; |
| else if (error_code == EAGAIN || error_code == EWOULDBLOCK) |
| { |
| /* The kernel might return EAGAIN for other reasons than a |
| non-blocking socket. But if the socket is not blocking, |
| it is not ours, so report the error. */ |
| int mode = __fcntl (fd, F_GETFL, 0); |
| if (mode < 0 || (mode & O_NONBLOCK) != 0) |
| terminate = true; |
| } |
| if (terminate) |
| { |
| char message[200]; |
| if (family < 0) |
| __snprintf (message, sizeof (message), |
| "Unexpected error %d on netlink descriptor %d", |
| error_code, fd); |
| else |
| __snprintf (message, sizeof (message), |
| "Unexpected error %d on netlink descriptor %d" |
| " (address family %d)", |
| error_code, fd, family); |
| __libc_fatal (message); |
| } |
| else |
| /* Restore orignal errno value. */ |
| __set_errno (error_code); |
| } |
| else if (result < sizeof (struct nlmsghdr)) |
| { |
| char message[200]; |
| int family = get_address_family (fd); |
| if (family < 0) |
| __snprintf (message, sizeof (message), |
| "Unexpected netlink response of size %zd" |
| " on descriptor %d", |
| result, fd); |
| else |
| __snprintf (message, sizeof (message), |
| "Unexpected netlink response of size %zd" |
| " on descriptor %d (address family %d)", |
| result, fd, family); |
| __libc_fatal (message); |
| } |
| } |
| libc_hidden_def (__netlink_assert_response) |
