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/* Copyright (C) 2001-2023 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 <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ucontext.h>
#include <unistd.h>
static ucontext_t ctx[3];
static int was_in_f1;
static int was_in_f2;
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 (-1);
}
if (swapcontext (&ctx[1], &ctx[2]) != 0)
{
printf ("%s: swapcontext: %m\n", __FUNCTION__);
exit (1);
}
puts ("finish f1");
was_in_f1 = 1;
}
static void
f2 (void)
{
char on_stack[1];
puts ("start f2");
printf ("&on_stack=%p\n", on_stack);
if (&on_stack[0] < &st2[0] || &on_stack[0] >= st2 + sizeof (st2))
{
printf ("%s: memory stack is not where it belongs!", __FUNCTION__);
exit (1);
}
if (swapcontext (&ctx[2], &ctx[1]) != 0)
{
printf ("%s: swapcontext: %m\n", __FUNCTION__);
exit (1);
}
puts ("finish f2");
was_in_f2 = 1;
}
void
test_stack (volatile int a, volatile int b,
volatile int c, volatile int d)
{
volatile int e = 5;
volatile int f = 6;
ucontext_t uc;
/* Test for cases where getcontext is clobbering the callers
stack, including parameters. */
getcontext (&uc);
if (a != 1)
{
printf ("%s: getcontext clobbers parm a\n", __FUNCTION__);
exit (1);
}
if (b != 2)
{
printf ("%s: getcontext clobbers parm b\n", __FUNCTION__);
exit (1);
}
if (c != 3)
{
printf ("%s: getcontext clobbers parm c\n", __FUNCTION__);
exit (1);
}
if (d != 4)
{
printf ("%s: getcontext clobbers parm d\n", __FUNCTION__);
exit (1);
}
if (e != 5)
{
printf ("%s: getcontext clobbers varible e\n", __FUNCTION__);
exit (1);
}
if (f != 6)
{
printf ("%s: getcontext clobbers variable f\n", __FUNCTION__);
exit (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 (1);
}
}
int
main (void)
{
atexit (check_called);
char st1[32768];
stack_t stack_before, stack_after;
sigaltstack (NULL, &stack_before);
puts ("making contexts");
if (getcontext (&ctx[1]) != 0)
{
if (errno == ENOSYS)
{
back_in_main = 1;
exit (0);
}
printf ("%s: getcontext: %m\n", __FUNCTION__);
exit (1);
}
test_stack (1, 2, 3, 4);
/* Play some tricks with this context. */
if (++global == 1)
if (setcontext (&ctx[1]) != 0)
{
printf ("%s: setcontext: %m\n", __FUNCTION__);
exit (1);
}
if (global != 2)
{
printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
exit (1);
}
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 (1);
}
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 (1);
}
puts ("back at main program");
back_in_main = 1;
sigaltstack (NULL, &stack_after);
if (was_in_f1 == 0)
{
puts ("didn't reach f1");
exit (1);
}
if (was_in_f2 == 0)
{
puts ("didn't reach f2");
exit (1);
}
/* Check sigaltstack state is not clobbered as in BZ #16629. */
if (stack_before.ss_sp != stack_after.ss_sp)
{
printf ("stack ss_sp mismatch: %p %p\n",
stack_before.ss_sp, stack_after.ss_sp);
exit (1);
}
if (stack_before.ss_size != stack_after.ss_size)
{
printf ("stack ss_size mismatch: %zd %zd\n",
stack_before.ss_size, stack_after.ss_size);
exit (1);
}
puts ("test succeeded");
return 0;
}
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