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/* This testcase is part of GDB, the GNU debugger.
Copyright 2004-2020 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;
}
}
int
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);
return 0;
}
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