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
94
95
96
97
98
99
100
101
102
103
104
105
|
/* This testcase is part of GDB, the GNU debugger.
Copyright 2004-2019 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/time.h>
static volatile int done[2];
static volatile int repeats[2];
static int itimer[2] = { ITIMER_REAL, ITIMER_VIRTUAL };
static int alarm[2] = { SIGALRM, SIGVTALRM };
static void
handler (int sig)
{
int sigi;
switch (sig)
{
case SIGALRM: sigi = 0; break;
case SIGVTALRM: sigi = 1; break;
default: abort ();
}
if (repeats[sigi]++ > 3)
{
/* Hit with enough signals, cancel everything and get out. */
{
struct itimerval itime;
memset (&itime, 0, sizeof (itime));
setitimer (itimer[sigi], &itime, NULL);
}
{
struct sigaction action;
memset (&action, 0, sizeof (action));
action.sa_handler = SIG_IGN;
sigaction (sig, &action, NULL);
}
done[sigi] = 1;
return;
}
/* Set up a nested virtual timer. */
while (1)
{
/* Wait until a signal has become pending, that way when this
handler returns it will be immediatly delivered leading to
back-to-back signals. */
sigset_t set;
sigemptyset (&set);
if (sigpending (&set) < 0)
{
perror ("sigrepeat");
abort ();
}
if (sigismember (&set, sig))
break;
}
} /* handler */
int
main ()
{
int i;
/* Set up the signal handler. */
for (i = 0; i < 2; i++)
{
struct sigaction action;
memset (&action, 0, sizeof (action));
action.sa_handler = handler;
sigaction (alarm[i], &action, NULL);
}
/* Set up a rapidly repeating timers. A timer, rather than SIGSEGV,
is used as after a timer handler returns the interrupted code can
safely resume. The intent is for the program to swamp GDB with a
backlog of pending signals. */
for (i = 0; i < 2; i++)
{
struct itimerval itime;
memset (&itime, 0, sizeof (itime));
itime.it_interval.tv_usec = 1;
itime.it_value.tv_usec = 250 * 1000;
setitimer (itimer[i], &itime, NULL);
}
/* Wait. */
while (!done[0] && !done[1]); /* infinite loop */
return 0;
}
|
