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
|
/* Check that the main thread's stack, on Linux, is automatically
extended down to the lowest valid address when a syscall happens.
Failure to do so was causing this test to fail on Linux amd64. */
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <sys/syscall.h>
#include <unistd.h>
#define VG_STRINGIFZ(__str) #__str
#define VG_STRINGIFY(__str) VG_STRINGIFZ(__str)
#if defined(VGO_linux) || defined(VGO_darwin)
#define __NR_READLINK VG_STRINGIFY(__NR_readlink)
extern long my_readlink ( const char* path );
asm(
".text\n"
".globl my_readlink\n"
"my_readlink:\n"
"\tsubq $0x1008,%rsp\n"
"\tmovq %rdi,%rdi\n" // path is in rdi
"\tmovq %rsp,%rsi\n" // &buf[0] -> rsi
"\tmovl $0x1000,%edx\n" // sizeof(buf) in rdx
"\tmovl $"__NR_READLINK",%eax\n" // syscall number
"\tsyscall\n"
"\taddq $0x1008,%rsp\n"
"\tret\n"
".previous\n"
);
#elif defined(VGO_solaris)
#define __NR_READLINKAT VG_STRINGIFY(SYS_readlinkat)
extern long my_readlink ( const char* path );
asm(
".text\n"
".globl my_readlink\n"
"my_readlink:\n"
"\tsubq $0x1008,%rsp\n"
"\tmovq %rdi,%rsi\n"
"\txorq %rdi,%rdi\n"
"\tmovq %rsp,%rdx\n"
"\tmovq $0x1000,%r10\n"
"\tmovl $"__NR_READLINKAT",%eax\n"
"\tsyscall\n"
"\taddq $0x1008,%rsp\n"
"\tret\n"
".previous\n"
);
#else
#error "Unknown OS"
#endif
long recurse ( const char* path, long count )
{
if (count <= 0) {
return my_readlink(path);
} else {
long r = recurse(path, count-1);
return r;
}
}
int main ( void )
{
long i, r;
for (i = 0; i < 2000; i++) {
printf("depth %ld: ", i );
r = recurse( "/proc/self", i );
if (r > 1) r = 1; /* to make the output repeatable */
assert(r >= 1);
printf("r = %ld\n", r);
}
return 0;
}
|
