gnu/dist/gdb6/gdb/testsuite/gdb.base/signull.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 1996, 1999, 2003, 2004 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  18    02111-1307, USA.  */
  19
  20 #include <signal.h>
  21 #include <setjmp.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 enum tests {
  26   code_entry_point, code_descriptor, data_read, data_write
  27 };
  28
  29 static volatile enum tests test;
  30
  31 /* Some basic types and zero buffers.  */
  32
  33 typedef long data_t;
  34 typedef long code_t (void);
  35 data_t *volatile data;
  36 code_t *volatile code;
  37 /* "desc" is intentionally initialized to a data object.  This is
  38    needed to test function descriptors on arches like ia64.  */
  39 data_t zero[10];
  40 code_t *volatile desc = (code_t *) (void *) zero;
  41
  42 sigjmp_buf env;
  43
  44 extern void
  45 keeper (int sig)
  46 {
  47   siglongjmp (env, 0);
  48 }
  49
  50 extern long
  51 bowler (void)
  52 {
  53   switch (test)
  54     {
  55     case data_read:
  56       /* Try to read address zero.  */
  57       return (*data);
  58     case data_write:
  59       /* Try to write (the assignment) to address zero.  */
  60       return (*data) = 1;
  61     case code_entry_point:
  62       /* For typical architectures, call a function at address
  63          zero.  */
  64       return (*code) ();
  65     case code_descriptor:
  66       /* For atypical architectures that use function descriptors,
  67          call a function descriptor, the code field of which is zero
  68          (which has the effect of jumping to address zero).  */
  69       return (*desc) ();
  70     }
  71 }
  72
  73 int
  74 main ()
  75 {
  76   static volatile int i;
  77
  78   struct sigaction act;
  79   memset (&act, 0, sizeof act);
  80   act.sa_handler = keeper;
  81   sigaction (SIGSEGV, &act, NULL);
  82
  83   for (i = 0; i < 10; i++)
  84     {
  85       sigsetjmp (env, 1);
  86       bowler ();
  87     }
  88 }