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/*
* Copyright (C) 2018-2020 Antony Antony <antony@phenome.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <https://www.gnu.org/licenses/gpl2.txt>.
*
* This program 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 General Public License
* for more details.
*/
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <linux/rtnetlink.h>
#include "kernel_netlink_query.h"
#include "lsw_socket.h"
#include "lswlog.h"
/* returns a file descriptor on success; -1 on error */
int nl_send_query(const struct nlmsghdr *req, int protocol, const struct logger *logger)
{
int nl_fd = cloexec_socket(AF_NETLINK, SOCK_DGRAM|SOCK_NONBLOCK, protocol);
if (nl_fd < 0) {
llog_error(logger, errno, "socket() in nl_send_query() protocol %d", protocol);
return nl_fd; /* -1 */
}
size_t len = req->nlmsg_len;
ssize_t r;
do {
r = write(nl_fd, req, len);
} while (r < 0 && errno == EINTR);
if (r < 0) {
llog_error(logger, errno, "netlink nl_send_query() write");
close(nl_fd);
return -1;
} else if ((size_t)r != len) {
llog_error(logger, 0/*no-strerr*/,
"netlink write() message truncated: %zd instead of %zu",
r, len);
close(nl_fd);
return -1;
}
return nl_fd;
}
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