1/* Test the stack guard.
2 Copyright (C) 2000-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#define _GNU_SOURCE
20
21#include <pthread.h>
22#include <assert.h>
23#include <unistd.h>
24#include <errno.h>
25#include <string.h>
26#include <stdio.h>
27
28size_t stacksize;
29
30void *
31thr (void *arg)
32{
33 int i;
34 char *foo;
35
36 foo = alloca (3 * stacksize / 4);
37 for (i = 0; i < sizeof foo; i++)
38 foo[i] = -1;
39
40 return (void *) 1;
41}
42
43int
44main (int argc, char *argv[])
45{
46 error_t err;
47 pid_t child;
48
49 child = fork ();
50 switch (child)
51 {
52 case -1:
53 error (1, errno, "fork");
54 break;
55
56 case 0:
57 {
58 pthread_attr_t attr;
59 pthread_t tid;
60 void *ret;
61
62 err = pthread_attr_init (attr: &attr);
63 assert_perror (err);
64
65 err = pthread_attr_getstacksize (attr: &attr, stacksize: &stacksize);
66 assert_perror (err);
67
68 err = pthread_attr_setguardsize (attr: &attr, guardsize: stacksize / 2);
69 if (err == ENOTSUP)
70 {
71 printf (format: "Stack guard attribute not supported.\n");
72 return 1;
73 }
74 assert_perror (err);
75
76 err = pthread_create (newthread: &tid, attr: &attr, start_routine: thr, arg: 0);
77 assert_perror (err);
78
79 err = pthread_attr_destroy (attr: &attr);
80 assert_perror (err);
81
82 err = pthread_join (th: tid, thread_return: &ret);
83 /* Should never be successful. */
84 printf (format: "Thread did not segfault!?!\n");
85 assert_perror (err);
86 return 0;
87 }
88
89 default:
90 {
91 pid_t pid;
92 int status;
93
94 pid = waitpid (child, &status, 0);
95 printf (format: "pid = %d; child = %d; status = %d\n", pid, child, status);
96 assert (pid == child);
97 assert (status != 0);
98 }
99 }
100
101 return 0;
102}
103

source code of glibc/htl/tests/test-4.c