1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
/*
Make sure that leak-check's pointer tracing avoids traps
*/
#include <stdio.h>
#include "memcheck/memcheck.h"
#include <sys/mman.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#if !defined(MAP_NORESERVE)
# define MAP_NORESERVE 0
#endif
int main()
{
char **volatile ptrs;
int i;
int fd;
char *map;
/* I _think_ the point of this is to fill ptrs with a pointer
to every 4th page in the entire address space, hence
guaranteeing that at least one of them points into one of
the below traps, and so checks that the leak checker
doesn't bomb when following them. That's fine on 32-bit
platforms, but hopeless for a 64-bit system. So the
following settings do achieve that on a 32-bit target but
merely make a 64-bit target give the same output without
properly testing it. */
int ptrbits, stepbits, stepsize, nptrs;
if (sizeof(void*) == 8) {
/* 64-bit machine */
ptrbits = 32; //bogus
stepbits = 14+1; //bogus
stepsize = (1 << stepbits);
nptrs = 1 << (ptrbits - stepbits);
} else {
/* 32-bit machine */
ptrbits = 32;
stepbits = 14;
stepsize = (1 << stepbits);
nptrs = 1 << (ptrbits - stepbits);
}
ptrs = malloc(nptrs * sizeof(char *));
for(i = 0; i < nptrs; i++)
ptrs[i] = (char *)((long)i << stepbits);
/* lay some traps */
map = mmap(0, stepsize * 2, PROT_NONE, MAP_PRIVATE|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
if (map == (char *)-1)
perror("trap 1 failed");
map = mmap(0, stepsize * 2, PROT_WRITE, MAP_PRIVATE|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
if (map == (char *)-1)
perror("trap 2 failed");
/* non-zero mmap of a zero-length file -> SIGBUS */
fd = open("./pointer-trace-test-file", O_RDWR | O_CREAT | O_EXCL, 0600);
unlink("./pointer-trace-test-file");
map = mmap(0, stepsize * 2, PROT_WRITE|PROT_READ, MAP_PRIVATE, fd, 0);
if (map == (char *)-1)
perror("trap 3 failed");
//printf("trap 3 = %p-%p\n", map, map+stepsize*2);
map = mmap(0, 256*1024, PROT_NONE, MAP_PRIVATE|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
if (map == (char *)-1)
perror("trap 4 failed");
else {
munmap(map, 256*1024);
VALGRIND_MAKE_MEM_DEFINED(map, 256*1024); /* great big fat lie */
}
VALGRIND_DO_LEAK_CHECK;
ptrs = 0;
return 0;
}
|