glibc/signal/tst-minsigstksz-4.c
Zack Weinberg fbbc9a4e34 Tests for minimal signal handler functionality in MINSIGSTKSZ space.
There is general agreement that the very short list of things that ISO
C says you can do in an async signal handler should all work when the
handler is running on an alternate signal stack with only MINSIGSTKSZ
space.  This patch adds tests to make sure those things do work.

To facilitate this, there is a new set of test support routines for
setting up alternate signal stacks; see support/xsignal.h for the API.

         * support/xsignal.h (xalloc_sigstack, xfree_sigstack)
         (xget_sigstack_location): New test support functions.
         * support/xsigstack.c: New file, implementing them.
         * support/tst-xsigstack.c: New test for them.
         * support/Makefile: Update.

         * signal/tst-minsigstksz-1.c
         * signal/tst-minsigstksz-2.c
         * signal/tst-minsigstksz-3.c
         * signal/tst-minsigstksz-3a.c
         * signal/tst-minsigstksz-4.c: New tests.
         * signal/Makefile: Run them.
2019-01-16 09:04:10 -05:00

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2.2 KiB
C

/* Tests of signal delivery on an alternate stack (quick_exit).
Copyright (C) 2019 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 <support/xsignal.h>
#include <support/support.h>
#include <support/check.h>
#include <stdlib.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 calls to quick_exit. Note that this is only
safe when there are no at_quick_exit callbacks. */
#define EXPECTED_STATUS 3
static void
handler (int unused)
{
quick_exit (EXPECTED_STATUS);
}
int
do_test (void)
{
void *sstk = xalloc_sigstack (0);
struct sigaction sa;
sa.sa_handler = handler;
sa.sa_flags = SA_RESTART | SA_ONSTACK;
sigfillset (&sa.sa_mask);
if (sigaction (SIGUSR1, &sa, 0))
FAIL_RET ("sigaction (SIGUSR1, handler): %m\n");
raise (SIGUSR1);
xfree_sigstack (sstk);
FAIL_RET ("test process was not terminated by quick_exit in signal handler");
}
#include <support/test-driver.c>