1 /* $OpenBSD: logflush.c,v 1.2 2021/10/24 21:24:21 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 2021 Alexander Bluhm <bluhm@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <sys/ioctl.h>
20 #include <sys/socket.h>
21
22 #include <err.h>
23 #include <fcntl.h>
24 #include <paths.h>
25 #include <stdarg.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <syslog.h>
29 #include <unistd.h>
30
31 __dead void
usage()32 usage()
33 {
34 fprintf(stderr, "usage: %s\n", getprogname());
35 exit(2);
36 }
37
38 int
main(int argc,char * argv[])39 main(int argc, char *argv[])
40 {
41 int pair[2], klog, val;
42
43 if (argc != 1)
44 usage();
45
46 if (socketpair(AF_UNIX, SOCK_DGRAM, PF_UNSPEC, pair) == -1)
47 err(1, "socketpair");
48
49 val = 1<<20;
50 if (setsockopt(pair[0], SOL_SOCKET, SO_RCVBUF, &val, sizeof(val)) == -1)
51 err(1, "setsockopt SO_RCVBUF");
52 if (setsockopt(pair[1], SOL_SOCKET, SO_SNDBUF, &val, sizeof(val)) == -1)
53 err(1, "setsockopt SO_SNDBUF");
54
55 if ((klog = open(_PATH_KLOG, O_RDONLY)) == -1)
56 err(1, "open %s", _PATH_KLOG);
57 /* Use /dev/klog to register sendsyslog(2) receiver. */
58 if (ioctl(klog, LIOCSFD, &pair[1]) == -1)
59 err(1, "ioctl klog LIOCSFD sendsyslog");
60 close(pair[1]);
61
62 /* Send message via libc, flushes log stash in kernel. */
63 openlog("syslogd-regress", LOG_PID, LOG_SYSLOG);
64 syslog(LOG_DEBUG, "logflush");
65
66 return 0;
67 }
68