stdlib/tst-setcontext11.c

   1 /* Check setjmp/longjmp within user 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 #include <errno.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <setjmp.h>
  24 #include <ucontext.h>
  25 #include <unistd.h>
  26
  27 static ucontext_t ctx[3];
  28 static jmp_buf jmpbuf;
  29
  30 static int was_in_f1;
  31 static int was_in_f2;
  32 static int longjmp_called;
  33
  34 static char st2[32768];
  35
  36 static void
  37 f1 (int a0, int a1, int a2, int a3)
  38 {
  39   printf ("start f1(a0=%x,a1=%x,a2=%x,a3=%x)\n", a0, a1, a2, a3);
  40
  41   if (a0 != 1 || a1 != 2 || a2 != 3 || a3 != -4)
  42     {
  43       puts ("arg mismatch");
  44       exit (EXIT_FAILURE);
  45     }
  46
  47   if (swapcontext (&ctx[1], &ctx[2]) != 0)
  48     {
  49       printf ("%s: swapcontext: %m\n", __FUNCTION__);
  50       exit (EXIT_FAILURE);
  51     }
  52   puts ("finish f1");
  53   was_in_f1 = 1;
  54 }
  55
  56 static void
  57 __attribute__ ((noinline, noclone))
  58 call_longjmp (void)
  59 {
  60   longjmp_called = 1;
  61   longjmp (jmpbuf, 1);
  62 }
  63
  64 static void
  65 f2 (void)
  66 {
  67   if (!longjmp_called)
  68     {
  69       if (setjmp (jmpbuf) == 0)
  70         call_longjmp ();
  71     }
  72
  73   puts ("start f2");
  74   if (swapcontext (&ctx[2], &ctx[1]) != 0)
  75     {
  76       printf ("%s: swapcontext: %m\n", __FUNCTION__);
  77       exit (EXIT_FAILURE);
  78     }
  79   puts ("finish f2");
  80   was_in_f2 = 1;
  81 }
  82
  83 volatile int global;
  84 static int back_in_main;
  85
  86 static void
  87 check_called (void)
  88 {
  89   if (back_in_main == 0)
  90     {
  91       puts ("program did not reach main again");
  92       _exit (EXIT_FAILURE);
  93     }
  94 }
  95
  96 static int
  97 do_test (void)
  98 {
  99   atexit (check_called);
 100
 101   char st1[32768];
 102
 103   puts ("making contexts");
 104   if (getcontext (&ctx[1]) != 0)
 105     {
 106       if (errno == ENOSYS)
 107         {
 108           back_in_main = 1;
 109           exit (EXIT_SUCCESS);
 110         }
 111
 112       printf ("%s: getcontext: %m\n", __FUNCTION__);
 113       exit (EXIT_FAILURE);
 114     }
 115
 116   /* Play some tricks with this context.  */
 117   if (++global == 1)
 118     if (setcontext (&ctx[1]) != 0)
 119       {
 120         printf ("%s: setcontext: %m\n", __FUNCTION__);
 121         exit (EXIT_FAILURE);
 122       }
 123   if (global != 2)
 124     {
 125       printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
 126       exit (EXIT_FAILURE);
 127     }
 128
 129   ctx[1].uc_stack.ss_sp = st1;
 130   ctx[1].uc_stack.ss_size = sizeof st1;
 131   ctx[1].uc_link = &ctx[0];
 132   {
 133     ucontext_t tempctx = ctx[1];
 134     makecontext (&ctx[1], (void (*) (void)) f1, 4, 1, 2, 3, -4);
 135
 136     /* Without this check, a stub makecontext can make us spin forever.  */
 137     if (memcmp (&tempctx, &ctx[1], sizeof ctx[1]) == 0)
 138       {
 139         puts ("makecontext was a no-op, presuming not implemented");
 140         return 0;
 141       }
 142   }
 143
 144   if (getcontext (&ctx[2]) != 0)
 145     {
 146       printf ("%s: second getcontext: %m\n", __FUNCTION__);
 147       exit (EXIT_FAILURE);
 148     }
 149   ctx[2].uc_stack.ss_sp = st2;
 150   ctx[2].uc_stack.ss_size = sizeof st2;
 151   ctx[2].uc_link = &ctx[1];
 152   makecontext (&ctx[2], f2, 0);
 153
 154   puts ("swapping contexts");
 155   if (swapcontext (&ctx[0], &ctx[2]) != 0)
 156     {
 157       printf ("%s: swapcontext: %m\n", __FUNCTION__);
 158       exit (EXIT_FAILURE);
 159     }
 160   puts ("back at main program");
 161   back_in_main = 1;
 162
 163   if (was_in_f1 == 0)
 164     {
 165       puts ("didn't reach f1");
 166       exit (EXIT_FAILURE);
 167     }
 168   if (was_in_f2 == 0)
 169     {
 170       puts ("didn't reach f2");
 171       exit (EXIT_FAILURE);
 172     }
 173
 174   puts ("test succeeded");
 175   return 0;
 176 }
 177
 178 #include <support/test-driver.c>