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
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
/* Make sure that the stackaddr returned by pthread_getattr_np is
reachable.
Copyright (C) 2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <string.h>
#include <sys/resource.h>
#include <pthread.h>
#include <alloca.h>
/* Move the stack pointer so that stackaddr is accessible and then check if it
really is accessible. This will segfault if it fails. */
static void
allocate_and_test (void *stackaddr)
{
void *mem = &mem;
/* FIXME: The difference will be negative for _STACK_GROWSUP. */
mem = alloca ((size_t) (mem - stackaddr));
*(int *)(mem) = 0;
}
static int
get_self_pthread_attr (const char *id, void **stackaddr, size_t *stacksize)
{
pthread_attr_t attr;
int ret;
pthread_t me = pthread_self ();
if ((ret = pthread_getattr_np (me, &attr)))
{
printf ("%s: pthread_getattr_np failed: %s\n", id, strerror (ret));
return 1;
}
if ((ret = pthread_attr_getstack (&attr, stackaddr, stacksize)))
{
printf ("%s: pthread_attr_getstack returned error: %s\n", id,
strerror (ret));
return 1;
}
return 0;
}
/* Verify that the stack size returned by pthread_getattr_np is usable when
the returned value is subject to rlimit. */
static int
check_stack_top (void)
{
struct rlimit stack_limit;
void *stackaddr;
size_t stacksize = 0;
int ret;
puts ("Verifying that stack top is accessible");
ret = getrlimit (RLIMIT_STACK, &stack_limit);
if (ret)
{
perror ("getrlimit failed");
return 1;
}
if (get_self_pthread_attr ("check_stack_top", &stackaddr, &stacksize))
return 1;
/* Reduce the rlimit to a page less that what is currently being returned so
that we ensure that pthread_getattr_np uses rlimit. The figure is
intentionally unaligned so to verify that pthread_getattr_np returns an
aligned stacksize that correctly fits into the rlimit. We don't bother
about the case where the stack is limited by the vma below it and not by
the rlimit because the stacksize returned in that case is computed from
the end of that vma and is hence safe. */
stack_limit.rlim_cur = stacksize - 4095;
printf ("Adjusting RLIMIT_STACK to %zu\n", stack_limit.rlim_cur);
if ((ret = setrlimit (RLIMIT_STACK, &stack_limit)))
{
perror ("setrlimit failed");
return 1;
}
if (get_self_pthread_attr ("check_stack_top2", &stackaddr, &stacksize))
return 1;
printf ("Adjusted rlimit: stacksize=%zu, stackaddr=%p\n", stacksize,
stackaddr);
allocate_and_test (stackaddr);
puts ("Stack top tests done");
return 0;
}
/* TODO: Similar check for thread stacks once the thread stack sizes are
fixed. */
static int
do_test (void)
{
return check_stack_top ();
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
|
