1/* Test of signal delivery on an alternate stack with MINSIGSTKSZ size.
2 Copyright (C) 2020-2022 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#include <signal.h>
20#include <stdlib.h>
21#include <string.h>
22#include <unistd.h>
23#include <support/check.h>
24#include <support/support.h>
25
26static volatile sig_atomic_t handler_run;
27
28static void
29handler (int signo)
30{
31 /* Clear a bit of on-stack memory. */
32 volatile char buffer[256];
33 for (size_t i = 0; i < sizeof (buffer); ++i)
34 buffer[i] = 0;
35 handler_run = 1;
36}
37
38int
39do_test (void)
40{
41 size_t stack_buffer_size = 64 * 1024 * 1024;
42 void *stack_buffer = xmalloc (n: stack_buffer_size);
43 void *stack_end = stack_buffer + stack_buffer_size;
44 memset (stack_buffer, 0xCC, stack_buffer_size);
45
46 void *stack_bottom = stack_buffer + (stack_buffer_size + MINSIGSTKSZ) / 2;
47 void *stack_top = stack_bottom + MINSIGSTKSZ;
48 stack_t stack =
49 {
50 .ss_sp = stack_bottom,
51 .ss_size = MINSIGSTKSZ,
52 };
53 if (sigaltstack (ss: &stack, NULL) < 0)
54 FAIL_RET ("sigaltstack: %m\n");
55
56 struct sigaction act =
57 {
58 .sa_handler = handler,
59 .sa_flags = SA_ONSTACK,
60 };
61 if (sigaction (SIGUSR1, act: &act, NULL) < 0)
62 FAIL_RET ("sigaction: %m\n");
63
64 if (kill (pid: getpid (), SIGUSR1) < 0)
65 FAIL_RET ("kill: %m\n");
66
67 if (handler_run != 1)
68 FAIL_RET ("handler did not run\n");
69
70 for (void *p = stack_buffer; p < stack_bottom; ++p)
71 if (*(unsigned char *) p != 0xCC)
72 FAIL_RET ("changed byte %ld bytes below configured stack\n",
73 (long) (stack_bottom - p));
74 for (void *p = stack_top; p < stack_end; ++p)
75 if (*(unsigned char *) p != 0xCC)
76 FAIL_RET ("changed byte %ld bytes above configured stack\n",
77 (long) (p - stack_top));
78
79 free (ptr: stack_buffer);
80
81 return 0;
82}
83
84#include <support/test-driver.c>
85

source code of glibc/signal/tst-minsigstksz-5.c