mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-26 12:41:05 +00:00
132 lines
4.0 KiB
C
132 lines
4.0 KiB
C
/* Tests of signal delivery on an alternate stack (nonlethal).
|
|
Copyright (C) 2019-2020 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 <support/xsignal.h>
|
|
#include <support/support.h>
|
|
#include <support/check.h>
|
|
|
|
/* C2011 7.4.1.1p5 specifies that only the following operations are
|
|
guaranteed to be well-defined inside an asynchronous signal handler:
|
|
* any operation on a lock-free atomic object
|
|
* assigning a value to an object declared as volatile sig_atomic_t
|
|
* calling abort, _Exit, quick_exit, or signal
|
|
* signal may only be called with its first argument equal to the
|
|
number of the signal that caused the handler to be called
|
|
|
|
We use this list as a guideline for the set of operations that ought
|
|
also to be safe in a _synchronous_ signal delivered on an alternate
|
|
signal stack with only MINSIGSTKSZ bytes of space.
|
|
|
|
This test program tests all of the above operations that do not,
|
|
one way or another, cause the program to be terminated. */
|
|
|
|
/* We do not try to test atomic operations exhaustively, only a simple
|
|
atomic counter increment. This is only safe if atomic_[u]int is
|
|
unconditionally lock-free. */
|
|
#ifdef __STDC_NO_ATOMICS__
|
|
# define TEST_ATOMIC_OPS 0
|
|
#else
|
|
# include <stdatomic.h>
|
|
# if ATOMIC_INT_LOCK_FREE != 2
|
|
# define TEST_ATOMIC_OPS 0
|
|
# else
|
|
# define TEST_ATOMIC_OPS 1
|
|
# endif
|
|
#endif
|
|
|
|
static volatile sig_atomic_t signal_flag = 0;
|
|
static volatile sig_atomic_t signal_err = 0;
|
|
static void
|
|
handler_set_flag (int unused)
|
|
{
|
|
signal_flag = 1;
|
|
}
|
|
|
|
static void
|
|
handler_set_flag_once (int sig)
|
|
{
|
|
signal_flag = 1;
|
|
if (signal (sig, SIG_IGN) == SIG_ERR)
|
|
/* It is not safe to call FAIL_EXIT1 here. Set another flag instead. */
|
|
signal_err = 1;
|
|
}
|
|
|
|
#if TEST_ATOMIC_OPS
|
|
static atomic_uint signal_count = 0;
|
|
static void
|
|
handler_count_up_1 (int unused)
|
|
{
|
|
atomic_fetch_add (&signal_count, 1);
|
|
}
|
|
#endif
|
|
|
|
int
|
|
do_test (void)
|
|
{
|
|
void *sstk = xalloc_sigstack (0);
|
|
struct sigaction sa;
|
|
|
|
/* Test 1: setting a volatile sig_atomic_t flag. */
|
|
sa.sa_handler = handler_set_flag;
|
|
sa.sa_flags = SA_RESTART | SA_ONSTACK;
|
|
sigfillset (&sa.sa_mask);
|
|
if (sigaction (SIGUSR1, &sa, 0))
|
|
FAIL_EXIT1 ("sigaction (SIGUSR1, handler_set_flag): %m\n");
|
|
|
|
TEST_VERIFY_EXIT (signal_flag == 0);
|
|
raise (SIGUSR1);
|
|
TEST_VERIFY_EXIT (signal_flag == 1);
|
|
signal_flag = 0;
|
|
raise (SIGUSR1);
|
|
TEST_VERIFY_EXIT (signal_flag == 1);
|
|
signal_flag = 0;
|
|
|
|
/* Test 1: setting a volatile sig_atomic_t flag and then ignoring
|
|
further delivery of the signal. */
|
|
sa.sa_handler = handler_set_flag_once;
|
|
if (sigaction (SIGUSR1, &sa, 0))
|
|
FAIL_EXIT1 ("sigaction (SIGUSR1, handler_set_flag_once): %m\n");
|
|
|
|
raise (SIGUSR1);
|
|
TEST_VERIFY_EXIT (signal_flag == 1);
|
|
/* Note: if signal_err is 1, a system call failed, but we can't
|
|
report the error code because errno is indeterminate. */
|
|
TEST_VERIFY_EXIT (signal_err == 0);
|
|
|
|
signal_flag = 0;
|
|
raise (SIGUSR1);
|
|
TEST_VERIFY_EXIT (signal_flag == 0);
|
|
TEST_VERIFY_EXIT (signal_err == 0);
|
|
|
|
#if TEST_ATOMIC_OPS
|
|
sa.sa_handler = handler_count_up_1;
|
|
if (sigaction (SIGUSR1, &sa, 0))
|
|
FAIL_EXIT1 ("sigaction (SIGUSR1, handler_count_up_1): %m\n");
|
|
|
|
raise (SIGUSR1);
|
|
TEST_VERIFY_EXIT (atomic_load (&signal_count) == 1);
|
|
raise (SIGUSR1);
|
|
TEST_VERIFY_EXIT (atomic_load (&signal_count) == 2);
|
|
#endif
|
|
|
|
xfree_sigstack (sstk);
|
|
return 0;
|
|
}
|
|
|
|
#include <support/test-driver.c>
|