1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
/* This testcase is part of GDB, the GNU debugger.
Copyright 2004, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
enum level { MAIN, OUTER, INNER, LEAF, NR_LEVELS };
/* Levels completed flag. */
volatile enum level level = NR_LEVELS;
void catcher (int signal);
void
thrower (enum level next_level, int sig, int itimer, int on_stack)
{
level = next_level;
/* Set up the signal handler. */
{
struct sigaction act;
memset (&act, 0, sizeof (act));
act.sa_handler = catcher;
act.sa_flags |= on_stack;
sigaction (sig, &act, NULL);
}
/* Set up a one-off timer. A timer, rather than SIGSEGV, is used as
after a timer handler finishes the interrupted code can safely
resume. */
{
struct itimerval itime;
memset (&itime, 0, sizeof (itime));
itime.it_value.tv_usec = 250 * 1000;
setitimer (itimer, &itime, NULL);
}
/* Wait. */
while (level != LEAF);
}
void
catcher (int signal)
{
/* Find the next level. */
switch (level)
{
case MAIN:
thrower (OUTER, SIGALRM, ITIMER_REAL, SA_ONSTACK);
break;
case OUTER:
thrower (INNER, SIGVTALRM, ITIMER_VIRTUAL, SA_ONSTACK);
break;
case INNER:
level = LEAF;
return;
}
}
main ()
{
/* Set up the altstack. */
{
static char stack[SIGSTKSZ * NR_LEVELS];
stack_t alt;
memset (&alt, 0, sizeof (alt));
alt.ss_sp = stack;
alt.ss_size = SIGSTKSZ;
alt.ss_flags = 0;
if (sigaltstack (&alt, NULL) < 0)
{
perror ("sigaltstack");
exit (0);
}
}
level = MAIN;
catcher (0);
}
|
GitWeb