stdlib/tst-setcontext10.c

   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
  34 static jmp_buf jmpbuf;
  35 static ucontext_t ctx;
  36
  37 static void f2 (void);
  38
  39 static void
  40 __attribute__ ((noinline, noclone))
  41 f1 (void)
  42 {
  43   printf ("start f1\n");
  44   f2 ();
  45 }
  46
  47 static void
  48 __attribute__ ((noinline, noclone))
  49 f2 (void)
  50 {
  51   printf ("start f2\n");
  52   if (setcontext (&ctx) != 0)
  53     {
  54       printf ("%s: setcontext: %m\n", __FUNCTION__);
  55       exit (EXIT_FAILURE);
  56     }
  57 }
  58
  59 static void
  60 f3 (void)
  61 {
  62   printf ("start f3\n");
  63   longjmp (jmpbuf, 1);
  64 }
  65
  66 static int
  67 __attribute__ ((noinline, noclone))
  68 do_test_1 (void)
  69 {
  70   char st1[32768];
  71
  72   if (setjmp (jmpbuf) != 0)
  73     return 0;
  74
  75   puts ("making contexts");
  76   if (getcontext (&ctx) != 0)
  77     {
  78       printf ("%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 (&ctx, (void (*) (void)) f3, 0);
  85   f1 ();
  86   puts ("FAIL: returned from f1 ()");
  87   exit (EXIT_FAILURE);
  88 }
  89
  90 static int
  91 do_test (void)
  92 {
  93   return do_test_1 ();
  94 }
  95
  96 #include <support/test-driver.c>