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/* Test of signal delivery on an alternate stack with MINSIGSTKSZ size.
Copyright (C) 2020-2024 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
<https://www.gnu.org/licenses/>. */
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <support/check.h>
#include <support/support.h>
static volatile sig_atomic_t handler_run;
static void
handler (int signo)
{
/* Clear a bit of on-stack memory. */
volatile char buffer[256];
for (size_t i = 0; i < sizeof (buffer); ++i)
buffer[i] = 0;
handler_run = 1;
}
int
do_test (void)
{
size_t stack_buffer_size = 64 * 1024 * 1024;
void *stack_buffer = xmalloc (stack_buffer_size);
void *stack_end = stack_buffer + stack_buffer_size;
memset (stack_buffer, 0xCC, stack_buffer_size);
void *stack_bottom = stack_buffer + (stack_buffer_size + MINSIGSTKSZ) / 2;
void *stack_top = stack_bottom + MINSIGSTKSZ;
stack_t stack =
{
.ss_sp = stack_bottom,
.ss_size = MINSIGSTKSZ,
};
if (sigaltstack (&stack, NULL) < 0)
FAIL_RET ("sigaltstack: %m\n");
struct sigaction act =
{
.sa_handler = handler,
.sa_flags = SA_ONSTACK,
};
if (sigaction (SIGUSR1, &act, NULL) < 0)
FAIL_RET ("sigaction: %m\n");
if (kill (getpid (), SIGUSR1) < 0)
FAIL_RET ("kill: %m\n");
if (handler_run != 1)
FAIL_RET ("handler did not run\n");
for (void *p = stack_buffer; p < stack_bottom; ++p)
if (*(unsigned char *) p != 0xCC)
FAIL_RET ("changed byte %ld bytes below configured stack\n",
(long) (stack_bottom - p));
for (void *p = stack_top; p < stack_end; ++p)
if (*(unsigned char *) p != 0xCC)
FAIL_RET ("changed byte %ld bytes above configured stack\n",
(long) (p - stack_top));
free (stack_buffer);
return 0;
}
#include <support/test-driver.c>
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