1 #include <limits.h>
2
3 #include <sys/types.h>
4 #include <sys/mman.h>
5 #include <sys/stat.h>
6 #include <fcntl.h>
7 #ifndef MAP_ANON
8 #ifdef MAP_ANONYMOUS
9 #define MAP_ANON MAP_ANONYMOUS
10 #else
11 #define MAP_ANON MAP_FILE
12 #endif
13 #endif
14 #ifndef MAP_FILE
15 #define MAP_FILE 0
16 #endif
17 #ifndef MAP_FIXED
18 #define MAP_FIXED 0
19 #endif
20
21 #define MAP_START (void *)0x7fff8000
22 #define MAP_LEN 0x10000
23
24 #define OFFSET (MAP_LEN/2 - 2 * sizeof (char));
25
f(int s,char * p)26 f (int s, char *p)
27 {
28 int i;
29 for (i = s; i >= 0 && &p[i] < &p[40]; i++)
30 {
31 p[i] = -2;
32 }
33 }
34
main()35 main ()
36 {
37 #ifdef MAP_ANON
38 char *p;
39 int dev_zero;
40
41 dev_zero = open ("/dev/zero", O_RDONLY);
42 /* -1 is OK when we have MAP_ANON; else mmap will flag an error. */
43 if (INT_MAX != 0x7fffffffL || sizeof (char *) != sizeof (int))
44 exit (0);
45 p = mmap (MAP_START, MAP_LEN, PROT_READ|PROT_WRITE,
46 MAP_ANON|MAP_FIXED|MAP_PRIVATE, dev_zero, 0);
47 if (p != (char *)-1)
48 {
49 p += OFFSET;
50 p[39] = 0;
51 f (0, p);
52 if (p[39] != (char)-2)
53 abort ();
54 p[39] = 0;
55 f (-1, p);
56 if (p[39] != 0)
57 abort ();
58 }
59 #endif
60 exit (0);
61 }
62