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/* Check setjmp/longjmp within user context.
Copyright (C) 2023-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <setjmp.h>
#include <ucontext.h>
#include <unistd.h>
static ucontext_t ctx[3];
static jmp_buf jmpbuf;
static int was_in_f1;
static int was_in_f2;
static int longjmp_called;
static char st2[32768];
static void
f1 (int a0, int a1, int a2, int a3)
{
printf ("start f1(a0=%x,a1=%x,a2=%x,a3=%x)\n", a0, a1, a2, a3);
if (a0 != 1 || a1 != 2 || a2 != 3 || a3 != -4)
{
puts ("arg mismatch");
exit (EXIT_FAILURE);
}
if (swapcontext (&ctx[1], &ctx[2]) != 0)
{
printf ("%s: swapcontext: %m\n", __FUNCTION__);
exit (EXIT_FAILURE);
}
puts ("finish f1");
was_in_f1 = 1;
}
static void
__attribute_optimization_barrier__
call_longjmp (void)
{
longjmp_called = 1;
longjmp (jmpbuf, 1);
}
static void
f2 (void)
{
if (!longjmp_called)
{
if (setjmp (jmpbuf) == 0)
call_longjmp ();
}
puts ("start f2");
if (swapcontext (&ctx[2], &ctx[1]) != 0)
{
printf ("%s: swapcontext: %m\n", __FUNCTION__);
exit (EXIT_FAILURE);
}
puts ("finish f2");
was_in_f2 = 1;
}
volatile int global;
static int back_in_main;
static void
check_called (void)
{
if (back_in_main == 0)
{
puts ("program did not reach main again");
_exit (EXIT_FAILURE);
}
}
static int
do_test (void)
{
atexit (check_called);
char st1[32768];
puts ("making contexts");
if (getcontext (&ctx[1]) != 0)
{
if (errno == ENOSYS)
{
back_in_main = 1;
exit (EXIT_SUCCESS);
}
printf ("%s: getcontext: %m\n", __FUNCTION__);
exit (EXIT_FAILURE);
}
/* Play some tricks with this context. */
if (++global == 1)
if (setcontext (&ctx[1]) != 0)
{
printf ("%s: setcontext: %m\n", __FUNCTION__);
exit (EXIT_FAILURE);
}
if (global != 2)
{
printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
exit (EXIT_FAILURE);
}
ctx[1].uc_stack.ss_sp = st1;
ctx[1].uc_stack.ss_size = sizeof st1;
ctx[1].uc_link = &ctx[0];
{
ucontext_t tempctx = ctx[1];
makecontext (&ctx[1], (void (*) (void)) f1, 4, 1, 2, 3, -4);
/* Without this check, a stub makecontext can make us spin forever. */
if (memcmp (&tempctx, &ctx[1], sizeof ctx[1]) == 0)
{
puts ("makecontext was a no-op, presuming not implemented");
return 0;
}
}
if (getcontext (&ctx[2]) != 0)
{
printf ("%s: second getcontext: %m\n", __FUNCTION__);
exit (EXIT_FAILURE);
}
ctx[2].uc_stack.ss_sp = st2;
ctx[2].uc_stack.ss_size = sizeof st2;
ctx[2].uc_link = &ctx[1];
makecontext (&ctx[2], f2, 0);
puts ("swapping contexts");
if (swapcontext (&ctx[0], &ctx[2]) != 0)
{
printf ("%s: swapcontext: %m\n", __FUNCTION__);
exit (EXIT_FAILURE);
}
puts ("back at main program");
back_in_main = 1;
if (was_in_f1 == 0)
{
puts ("didn't reach f1");
exit (EXIT_FAILURE);
}
if (was_in_f2 == 0)
{
puts ("didn't reach f2");
exit (EXIT_FAILURE);
}
puts ("test succeeded");
return 0;
}
#include <support/test-driver.c>
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