1/*
2 * Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 *    derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifdef HAVE_CONFIG_H
29# include "config.h"
30#endif
31#include <dlfcn.h>
32#include <fcntl.h>
33#include <unistd.h>
34#include <sys/mman.h>
35#include <sys/wait.h>
36#include <sys/sendfile.h>
37
38int main(void)
39{
40	const unsigned long pagesize = sysconf(_SC_PAGESIZE);
41
42#ifdef __s390__
43	/*
44	 * The si_addr field is unreliable:
45	 * https://marc.info/?l=linux-s390&m=142515870124248&w=2
46	 */
47	return 77;
48#endif
49
50	/* write instruction pointer length to the log */
51	if (write(-1, NULL, 2 * sizeof(void *)) >= 0)
52		return 77;
53
54	/* just a noticeable line in the log */
55	if (munmap(&main, 0) >= 0)
56		return 77;
57
58	int pid = fork();
59	if (pid < 0)
60		return 77;
61
62	if (!pid) {
63		const unsigned long mask = ~(pagesize - 1);
64		unsigned long addr = (unsigned long) &main & mask;
65		unsigned long size = pagesize << 1;
66
67#ifdef HAVE_DLADDR
68		Dl_info info;
69		if (dladdr(&main, &info)) {
70			const unsigned long base =
71				(unsigned long) info.dli_fbase & mask;
72			if (base < addr) {
73				size += addr - base;
74				addr = base;
75			}
76		} else
77#endif
78		{
79			addr -= size;
80			size <<= 1;
81		}
82
83		/* SIGSEGV is expected */
84		(void) munmap((void *) addr, size);
85		(void) munmap((void *) addr, size);
86		return 77;
87	}
88
89	int status;
90	if (wait(&status) != pid ||
91	    !WIFSIGNALED(status) ||
92	    WTERMSIG(status) != SIGSEGV)
93		return 77;
94
95	/* dump process map for debug purposes */
96	close(0);
97	if (!open("/proc/self/maps", O_RDONLY))
98		(void) sendfile(1, 0, NULL, pagesize);
99
100	return 0;
101}
102