root/maint/gnulib/tests/test-sigsegv-catch-stackoverflow1.c

/* */

DEFINITIONS

1. stackoverflow_handler_continuation
2. stackoverflow_handler
3. recurse_1
4. recurse
5. main
6. main

   1 /* Test the stack overflow handler.
   2    Copyright (C) 2002-2021 Free Software Foundation, Inc.
   3 
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8 
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13 
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16 
  17 /* Written by Bruno Haible and Eric Blake.  */
  18 
  19 #include <config.h>
  20 
  21 /* Specification.  */
  22 #include "sigsegv.h"
  23 
  24 #include <stdio.h>
  25 #include <limits.h>
  26 
  27 #if HAVE_STACK_OVERFLOW_RECOVERY
  28 
  29 # if defined _WIN32 && !defined __CYGWIN__
  30   /* Windows doesn't have sigset_t.  */
  31   typedef int sigset_t;
  32 #  define sigemptyset(set)
  33 #  define sigprocmask(how,set,oldset)
  34 # endif
  35 
  36 # include <stddef.h> /* needed for NULL on SunOS4 */
  37 # include <stdlib.h> /* for abort, exit */
  38 # include <signal.h>
  39 # include <setjmp.h>
  40 # if HAVE_SETRLIMIT
  41 #  include <sys/types.h>
  42 #  include <sys/time.h>
  43 #  include <sys/resource.h>
  44 # endif
  45 # include "altstack-util.h"
  46 
  47 static jmp_buf mainloop;
  48 static sigset_t mainsigset;
  49 
  50 static volatile int pass = 0;
  51 
  52 static volatile char *stack_lower_bound;
  53 static volatile char *stack_upper_bound;
  54 
  55 static void
  56 stackoverflow_handler_continuation (void *arg1, void *arg2, void *arg3)
     /*  */
  57 {
  58   int arg = (int) (long) arg1;
  59   longjmp (mainloop, arg);
  60 }
  61 
  62 static void
  63 stackoverflow_handler (int emergency, stackoverflow_context_t scp)
     /*  */
  64 {
  65   char dummy;
  66   volatile char *addr = &dummy;
  67   if (!(addr >= stack_lower_bound && addr <= stack_upper_bound))
  68     abort ();
  69   pass++;
  70   printf ("Stack overflow %d caught.\n", pass);
  71   sigprocmask (SIG_SETMASK, &mainsigset, NULL);
  72   sigsegv_leave_handler (stackoverflow_handler_continuation,
  73                          (void *) (long) (emergency ? -1 : pass), NULL, NULL);
  74 }
  75 
  76 static volatile int *
  77 recurse_1 (int n, volatile int *p)
     /*  */
  78 {
  79   if (n < INT_MAX)
  80     *recurse_1 (n + 1, p) += n;
  81   return p;
  82 }
  83 
  84 static int
  85 recurse (volatile int n)
     /*  */
  86 {
  87   return *recurse_1 (n, &n);
  88 }
  89 
  90 int
  91 main ()
     /*  */
  92 {
  93   sigset_t emptyset;
  94 
  95 # if HAVE_SETRLIMIT && defined RLIMIT_STACK
  96   /* Before starting the endless recursion, try to be friendly to the user's
  97      machine.  On some Linux 2.2.x systems, there is no stack limit for user
  98      processes at all.  We don't want to kill such systems.  */
  99   struct rlimit rl;
 100   rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
 101   setrlimit (RLIMIT_STACK, &rl);
 102 # endif
 103 
 104   /* Prepare the storage for the alternate stack.  */
 105   prepare_alternate_stack ();
 106 
 107   /* Install the stack overflow handler.  */
 108   if (stackoverflow_install_handler (&stackoverflow_handler,
 109                                      mystack, MYSTACK_SIZE)
 110       < 0)
 111     exit (2);
 112   stack_lower_bound = mystack;
 113   stack_upper_bound = mystack + MYSTACK_SIZE - 1;
 114 
 115   /* Save the current signal mask.  */
 116   sigemptyset (&emptyset);
 117   sigprocmask (SIG_BLOCK, &emptyset, &mainsigset);
 118 
 119   /* Provoke two stack overflows in a row.  */
 120   switch (setjmp (mainloop))
 121     {
 122     case -1:
 123       printf ("emergency exit\n"); exit (1);
 124     case 0: case 1:
 125       printf ("Starting recursion pass %d.\n", pass + 1);
 126       recurse (0);
 127       printf ("no endless recursion?!\n"); exit (1);
 128     case 2:
 129       break;
 130     default:
 131       abort ();
 132     }
 133 
 134   /* Validate that the alternate stack did not overflow.  */
 135   check_alternate_stack_no_overflow ();
 136 
 137   printf ("Test passed.\n");
 138   exit (0);
 139 }
 140 
 141 #else
 142 
 143 int
 144 main ()
     /*  */
 145 {
 146   return 77;
 147 }
 148 
 149 #endif

/* */