1/* This testcase is part of GDB, the GNU debugger.
2
3   Copyright 2004, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4
5   This program is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program 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
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18#include <signal.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22#include <sys/time.h>
23
24enum level { MAIN, OUTER, INNER, LEAF, NR_LEVELS };
25
26/* Levels completed flag.  */
27volatile enum level level = NR_LEVELS;
28
29void catcher (int signal);
30
31void
32thrower (enum level next_level, int sig, int itimer, int on_stack)
33{
34  level = next_level;
35  /* Set up the signal handler.  */
36  {
37    struct sigaction act;
38    memset (&act, 0, sizeof (act));
39    act.sa_handler = catcher;
40    act.sa_flags |= on_stack;
41    sigaction (sig, &act, NULL);
42  }
43  /* Set up a one-off timer.  A timer, rather than SIGSEGV, is used as
44     after a timer handler finishes the interrupted code can safely
45     resume.  */
46  {
47    struct itimerval itime;
48    memset (&itime, 0, sizeof (itime));
49    itime.it_value.tv_usec = 250 * 1000;
50    setitimer (itimer, &itime, NULL);
51  }
52  /* Wait.  */
53  while (level != LEAF);
54}
55
56void
57catcher (int signal)
58{
59  /* Find the next level.  */
60  switch (level)
61    {
62    case MAIN:
63      thrower (OUTER, SIGALRM, ITIMER_REAL, SA_ONSTACK);
64      break;
65    case OUTER:
66      thrower (INNER, SIGVTALRM, ITIMER_VIRTUAL, SA_ONSTACK);
67      break;
68    case INNER:
69      level = LEAF;
70      return;
71    }
72}
73
74
75main ()
76{
77  /* Set up the altstack.  */
78  {
79    static char stack[SIGSTKSZ * NR_LEVELS];
80    stack_t alt;
81    memset (&alt, 0, sizeof (alt));
82    alt.ss_sp = stack;
83    alt.ss_size = SIGSTKSZ;
84    alt.ss_flags = 0;
85    if (sigaltstack (&alt, NULL) < 0)
86      {
87	perror ("sigaltstack");
88	exit (0);
89      }
90  }
91  level = MAIN;
92  catcher (0);
93}
94