1 /* Tests of signal delivery on an alternate stack (quick_exit).
2 Copyright (C) 2019-2022 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 <support/xsignal.h>
20 #include <support/support.h>
21 #include <support/check.h>
22 #include <stdlib.h>
23
24 /* C2011 7.4.1.1p5 specifies that only the following operations are
25 guaranteed to be well-defined inside an asynchronous signal handler:
26 * any operation on a lock-free atomic object
27 * assigning a value to an object declared as volatile sig_atomic_t
28 * calling abort, _Exit, quick_exit, or signal
29 * signal may only be called with its first argument equal to the
30 number of the signal that caused the handler to be called
31
32 We use this list as a guideline for the set of operations that ought
33 also to be safe in a _synchronous_ signal delivered on an alternate
34 signal stack with only MINSIGSTKSZ bytes of space.
35
36 This test program tests calls to quick_exit. Note that this is only
37 safe when there are no at_quick_exit callbacks. */
38
39 #define EXPECTED_STATUS 3
40
41 static void
handler(int unused)42 handler (int unused)
43 {
44 quick_exit (EXPECTED_STATUS);
45 }
46
47 int
do_test(void)48 do_test (void)
49 {
50 void *sstk = xalloc_sigstack (0);
51 struct sigaction sa;
52
53 sa.sa_handler = handler;
54 sa.sa_flags = SA_RESTART | SA_ONSTACK;
55 sigfillset (&sa.sa_mask);
56 if (sigaction (SIGUSR1, &sa, 0))
57 FAIL_RET ("sigaction (SIGUSR1, handler): %m\n");
58
59 raise (SIGUSR1);
60
61 xfree_sigstack (sstk);
62 FAIL_RET ("test process was not terminated by quick_exit in signal handler");
63 }
64
65 #include <support/test-driver.c>
66