1/* This testcase is part of GDB, the GNU debugger.
2
3   Copyright 2004 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 2 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, write to the Free Software
17   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18
19   Please email any bugs, comments, and/or additions to this file to:
20   bug-gdb@prep.ai.mit.edu  */
21
22#include <signal.h>
23#include <stdio.h>
24#include <stdlib.h>
25#include <string.h>
26#include <sys/time.h>
27
28enum level { MAIN, OUTER, INNER, LEAF, NR_LEVELS };
29
30/* Levels completed flag.  */
31volatile enum level level = NR_LEVELS;
32
33void catcher (int signal);
34
35void
36thrower (enum level next_level, int sig, int itimer, int on_stack)
37{
38  level = next_level;
39  /* Set up the signal handler.  */
40  {
41    struct sigaction act;
42    memset (&act, 0, sizeof (act));
43    act.sa_handler = catcher;
44    act.sa_flags |= on_stack;
45    sigaction (sig, &act, NULL);
46  }
47  /* Set up a one-off timer.  A timer, rather than SIGSEGV, is used as
48     after a timer handler finishes the interrupted code can safely
49     resume.  */
50  {
51    struct itimerval itime;
52    memset (&itime, 0, sizeof (itime));
53    itime.it_value.tv_usec = 250 * 1000;
54    setitimer (itimer, &itime, NULL);
55  }
56  /* Wait.  */
57  while (level != LEAF);
58}
59
60void
61catcher (int signal)
62{
63  /* Find the next level.  */
64  switch (level)
65    {
66    case MAIN:
67      thrower (OUTER, SIGALRM, ITIMER_REAL, SA_ONSTACK);
68      break;
69    case OUTER:
70      thrower (INNER, SIGVTALRM, ITIMER_VIRTUAL, SA_ONSTACK);
71      break;
72    case INNER:
73      level = LEAF;
74      return;
75    }
76}
77
78
79main ()
80{
81  /* Set up the altstack.  */
82  {
83    static char stack[SIGSTKSZ * NR_LEVELS];
84    struct sigaltstack alt;
85    memset (&alt, 0, sizeof (alt));
86    alt.ss_sp = stack;
87    alt.ss_size = SIGSTKSZ;
88    alt.ss_flags = 0;
89    if (sigaltstack (&alt, NULL) < 0)
90      {
91	perror ("sigaltstack");
92	exit (0);
93      }
94  }
95  level = MAIN;
96  catcher (0);
97}
98