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
pass(const char * fmt,unsigned long a,unsigned long b)26 static 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
fail(const char * fmt,unsigned long a,unsigned long b)36 static 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
main(void)47 int 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