1/* Check longjmp from user context to main context.
2 Copyright (C) 2023-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19/* When _FORTIFY_SOURCE is defined to 2, ____longjmp_chk is called,
20 instead of longjmp. ____longjmp_chk compares the relative stack
21 values to decide if it is called from a stack frame which called
22 setjmp. If not, ____longjmp_chk assumes that an alternate signal
23 stack is used. Since comparing the relative stack values isn't
24 reliable with user context, when there is no signal, ____longjmp_chk
25 will fail. Undefine _FORTIFY_SOURCE to avoid ____longjmp_chk. */
26#undef _FORTIFY_SOURCE
27
28#include <stdio.h>
29#include <stdlib.h>
30#include <setjmp.h>
31#include <ucontext.h>
32#include <unistd.h>
33
34static jmp_buf jmpbuf;
35static ucontext_t ctx;
36
37static void f2 (void);
38
39static void
40__attribute__ ((noinline, noclone))
41f1 (void)
42{
43 printf (format: "start f1\n");
44 f2 ();
45}
46
47static void
48__attribute__ ((noinline, noclone))
49f2 (void)
50{
51 printf (format: "start f2\n");
52 if (setcontext (&ctx) != 0)
53 {
54 printf (format: "%s: setcontext: %m\n", __FUNCTION__);
55 exit (EXIT_FAILURE);
56 }
57}
58
59static void
60f3 (void)
61{
62 printf (format: "start f3\n");
63 longjmp (jmpbuf, 1);
64}
65
66static int
67__attribute__ ((noinline, noclone))
68do_test_1 (void)
69{
70 char st1[32768];
71
72 if (setjmp (jmpbuf) != 0)
73 return 0;
74
75 puts (s: "making contexts");
76 if (getcontext (ucp: &ctx) != 0)
77 {
78 printf (format: "%s: getcontext: %m\n", __FUNCTION__);
79 exit (EXIT_FAILURE);
80 }
81 ctx.uc_stack.ss_sp = st1;
82 ctx.uc_stack.ss_size = sizeof st1;
83 ctx.uc_link = NULL;
84 makecontext (ucp: &ctx, func: (void (*) (void)) f3, argc: 0);
85 f1 ();
86 puts (s: "FAIL: returned from f1 ()");
87 exit (EXIT_FAILURE);
88}
89
90static int
91do_test (void)
92{
93 return do_test_1 ();
94}
95
96#include <support/test-driver.c>
97

source code of glibc/stdlib/tst-setcontext10.c