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/* Test the stack overflow handler.
Copyright (C) 2002-2021 Bruno Haible <bruno@clisp.org>
Copyright (C) 2010 Eric Blake <eblake@redhat.com>
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 2 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 <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "sigsegv.h"
#include <stdio.h>
#include <limits.h>
#if HAVE_STACK_OVERFLOW_RECOVERY
# if defined _WIN32 && !defined __CYGWIN__
/* Windows doesn't have sigset_t. */
typedef int sigset_t;
# define sigemptyset(set)
# define sigprocmask(how,set,oldset)
# endif
# include <stddef.h> /* needed for NULL on SunOS4 */
# include <stdlib.h> /* for abort, exit */
# include <signal.h>
# include <setjmp.h>
# if HAVE_SETRLIMIT
# include <sys/types.h>
# include <sys/time.h>
# include <sys/resource.h>
# endif
# include "altstack-util.h"
jmp_buf mainloop;
sigset_t mainsigset;
volatile int pass = 0;
volatile char *stack_lower_bound;
volatile char *stack_upper_bound;
static void
stackoverflow_handler_continuation (void *arg1, void *arg2, void *arg3)
{
int arg = (int) (long) arg1;
longjmp (mainloop, arg);
}
void
stackoverflow_handler (int emergency, stackoverflow_context_t scp)
{
char dummy;
volatile char *addr = &dummy;
if (!(addr >= stack_lower_bound && addr <= stack_upper_bound))
abort ();
pass++;
printf ("Stack overflow %d caught.\n", pass);
sigprocmask (SIG_SETMASK, &mainsigset, NULL);
sigsegv_leave_handler (stackoverflow_handler_continuation,
(void *) (long) (emergency ? -1 : pass), NULL, NULL);
}
volatile int *
recurse_1 (int n, volatile int *p)
{
if (n < INT_MAX)
*recurse_1 (n + 1, p) += n;
return p;
}
int
recurse (volatile int n)
{
return *recurse_1 (n, &n);
}
int
main ()
{
sigset_t emptyset;
# if HAVE_SETRLIMIT && defined RLIMIT_STACK
/* Before starting the endless recursion, try to be friendly to the user's
machine. On some Linux 2.2.x systems, there is no stack limit for user
processes at all. We don't want to kill such systems. */
struct rlimit rl;
rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
setrlimit (RLIMIT_STACK, &rl);
# endif
/* Prepare the storage for the alternate stack. */
prepare_alternate_stack ();
/* Install the stack overflow handler. */
if (stackoverflow_install_handler (&stackoverflow_handler,
mystack, SIGSTKSZ)
< 0)
exit (2);
stack_lower_bound = mystack;
stack_upper_bound = mystack + SIGSTKSZ - 1;
/* Save the current signal mask. */
sigemptyset (&emptyset);
sigprocmask (SIG_BLOCK, &emptyset, &mainsigset);
/* Provoke two stack overflows in a row. */
switch (setjmp (mainloop))
{
case -1:
printf ("emergency exit\n"); exit (1);
case 0: case 1:
printf ("Starting recursion pass %d.\n", pass + 1);
recurse (0);
printf ("no endless recursion?!\n"); exit (1);
case 2:
break;
default:
abort ();
}
/* Validate that the alternate stack did not overflow. */
check_alternate_stack_no_overflow ();
printf ("Test passed.\n");
exit (0);
}
#else
int
main ()
{
return 77;
}
#endif
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