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/* Check setjmp/longjmp between user contexts.
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 <stdio.h>
#include <stdlib.h>
#include <setjmp.h>
#include <ucontext.h>
#include <stackinfo.h>
static ucontext_t uctx_main, uctx_func1, uctx_func2;
const char *str1 = "\e[31mswapcontext(&uctx_func1, &uctx_main)\e[0m";
const char *str2 = "\e[34mswapcontext(&uctx_func2, &uctx_main)\e[0m";
const char *fmt1 = "\e[31m";
const char *fmt2 = "\e[34m";
static jmp_buf jmpbuf;
#define handle_error(msg) \
do { perror(msg); exit(EXIT_FAILURE); } while (0)
__attribute_optimization_barrier__
static void
func4(ucontext_t *uocp, ucontext_t *ucp, const char *str, const char *fmt)
{
printf(" %sfunc4: %s\e[0m\n", fmt, str);
if (swapcontext(uocp, ucp) == -1)
handle_error("swapcontext");
printf(" %sfunc4: returning\e[0m\n", fmt);
}
__attribute_optimization_barrier__
static void
func3(ucontext_t *uocp, ucontext_t *ucp, const char *str, const char *fmt)
{
printf(" %sfunc3: func4(uocp, ucp, str)\e[0m\n", fmt);
func4(uocp, ucp, str, fmt);
printf(" %sfunc3: returning\e[0m\n", fmt);
}
__attribute_optimization_barrier__
static void
func1(void)
{
while ( 1 )
{
printf(" \e[31mfunc1: func3(&uctx_func1, &uctx_main, str1)\e[0m\n");
if (setjmp (jmpbuf) != 0)
{
printf(" %sfunc1: from longjmp\e[0m\n", fmt1);
exit (EXIT_SUCCESS);
}
func3( &uctx_func1, &uctx_main, str1, fmt1);
}
}
__attribute_optimization_barrier__
static void
func2(void)
{
while ( 1 )
{
printf(" \e[34mfunc2: func3(&uctx_func2, &uctx_main, str2)\e[0m\n");
func3(&uctx_func2, &uctx_main, str2, fmt2);
printf(" %sfunc2: calling longjmp\e[0m\n", fmt2);
longjmp (jmpbuf, 1);
}
}
static int
do_test (void)
{
/* ____longjmp_chk has */
#if 0
#if _STACK_GROWS_DOWN
#define called_from(this, saved) ((this) < (saved))
#else
#define called_from(this, saved) ((this) > (saved))
#endif
/* If "env" is from a frame that called us, we're all set. */
if (called_from(this_frame, saved_frame))
__longjmp (env, val);
#endif
/* Arrange stacks for uctx_func1 and uctx_func2 so that called_from
is true when setjmp is called from uctx_func1 and longjmp is called
from uctx_func2. */
#if _STACK_GROWS_DOWN
# define UCTX_FUNC1_STACK 1
# define UCTX_FUNC2_STACK 0
#else
# define UCTX_FUNC1_STACK 0
# define UCTX_FUNC2_STACK 1
#endif
char func_stack[2][16384];
int i;
if (getcontext(&uctx_func1) == -1)
handle_error("getcontext");
uctx_func1.uc_stack.ss_sp = func_stack[UCTX_FUNC1_STACK];
uctx_func1.uc_stack.ss_size = sizeof (func_stack[UCTX_FUNC1_STACK]);
uctx_func1.uc_link = &uctx_main;
makecontext(&uctx_func1, func1, 0);
if (getcontext(&uctx_func2) == -1)
handle_error("getcontext");
uctx_func2.uc_stack.ss_sp = func_stack[UCTX_FUNC2_STACK];
uctx_func2.uc_stack.ss_size = sizeof (func_stack[UCTX_FUNC2_STACK]);
uctx_func2.uc_link = &uctx_func1;
makecontext(&uctx_func2, func2, 0);
for ( i = 0; i < 2; i++ )
{
if (swapcontext(&uctx_main, &uctx_func1) == -1)
handle_error("swapcontext");
printf(" \e[35mmain: swapcontext(&uctx_main, &uctx_func2)\n\e[0m");
if (swapcontext(&uctx_main, &uctx_func2) == -1)
handle_error("swapcontext");
printf(" \e[35mmain: swapcontext(&uctx_main, &uctx_func1)\n\e[0m");
}
exit(EXIT_FAILURE);
}
#include <support/test-driver.c>
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