1/*
2 * Copyright �� 2018 Alexey Dobriyan <adobriyan@gmail.com>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16/* Test readlink /proc/self/map_files/... with minimum address. */
17#include <errno.h>
18#include <sys/types.h>
19#include <sys/stat.h>
20#include <fcntl.h>
21#include <stdio.h>
22#include <unistd.h>
23#include <sys/mman.h>
24#include <stdlib.h>
25
26static void pass(const char *fmt, unsigned long a, unsigned long b)
27{
28	char name[64];
29	char buf[64];
30
31	snprintf(name, sizeof(name), fmt, a, b);
32	if (readlink(name, buf, sizeof(buf)) == -1)
33		exit(1);
34}
35
36static void fail(const char *fmt, unsigned long a, unsigned long b)
37{
38	char name[64];
39	char buf[64];
40
41	snprintf(name, sizeof(name), fmt, a, b);
42	if (readlink(name, buf, sizeof(buf)) == -1 && errno == ENOENT)
43		return;
44	exit(1);
45}
46
47int main(void)
48{
49	const int PAGE_SIZE = sysconf(_SC_PAGESIZE);
50	/*
51	 * va_max must be enough bigger than vm.mmap_min_addr, which is
52	 * 64KB/32KB by default. (depends on CONFIG_LSM_MMAP_MIN_ADDR)
53	 */
54	const unsigned long va_max = 1UL << 20;
55	unsigned long va;
56	void *p;
57	int fd;
58	unsigned long a, b;
59
60	fd = open("/dev/zero", O_RDONLY);
61	if (fd == -1)
62		return 1;
63
64	for (va = 0; va < va_max; va += PAGE_SIZE) {
65		p = mmap((void *)va, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_FILE|MAP_FIXED, fd, 0);
66		if (p == (void *)va)
67			break;
68	}
69	if (va == va_max) {
70		fprintf(stderr, "error: mmap doesn't like you\n");
71		return 1;
72	}
73
74	a = (unsigned long)p;
75	b = (unsigned long)p + PAGE_SIZE;
76
77	pass("/proc/self/map_files/%lx-%lx", a, b);
78	fail("/proc/self/map_files/ %lx-%lx", a, b);
79	fail("/proc/self/map_files/%lx -%lx", a, b);
80	fail("/proc/self/map_files/%lx- %lx", a, b);
81	fail("/proc/self/map_files/%lx-%lx ", a, b);
82	fail("/proc/self/map_files/0%lx-%lx", a, b);
83	fail("/proc/self/map_files/%lx-0%lx", a, b);
84	if (sizeof(long) == 4) {
85		fail("/proc/self/map_files/100000000%lx-%lx", a, b);
86		fail("/proc/self/map_files/%lx-100000000%lx", a, b);
87	} else if (sizeof(long) == 8) {
88		fail("/proc/self/map_files/10000000000000000%lx-%lx", a, b);
89		fail("/proc/self/map_files/%lx-10000000000000000%lx", a, b);
90	} else
91		return 1;
92
93	return 0;
94}
95