gdb/testsuite/gdb.base/signull.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 1996, 1999, 2003, 2004, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include <signal.h>
  20 #include <setjmp.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24 enum tests {
  25   code_entry_point, code_descriptor, data_read, data_write
  26 };
  27
  28 static volatile enum tests test;
  29
  30 /* Some basic types and zero buffers.  */
  31
  32 typedef long data_t;
  33 typedef long code_t (void);
  34 data_t *volatile data;
  35 code_t *volatile code;
  36 /* "desc" is intentionally initialized to a data object.  This is
  37    needed to test function descriptors on arches like ia64.  */
  38 data_t zero[10];
  39 code_t *volatile desc = (code_t *) (void *) zero;
  40
  41 sigjmp_buf env;
  42
  43 extern void
  44 keeper (int sig)
  45 {
  46   siglongjmp (env, 0);
  47 }
  48
  49 extern long
  50 bowler (void)
  51 {
  52   switch (test)
  53     {
  54     case data_read:
  55       /* Try to read address zero.  */
  56       return (*data);
  57     case data_write:
  58       /* Try to write (the assignment) to address zero.  */
  59       return (*data) = 1;
  60     case code_entry_point:
  61       /* For typical architectures, call a function at address
  62          zero.  */
  63       return (*code) ();
  64     case code_descriptor:
  65       /* For atypical architectures that use function descriptors,
  66          call a function descriptor, the code field of which is zero
  67          (which has the effect of jumping to address zero).  */
  68       return (*desc) ();
  69     }
  70 }
  71
  72 int
  73 main ()
  74 {
  75   static volatile int i;
  76
  77   struct sigaction act;
  78   memset (&act, 0, sizeof act);
  79   act.sa_handler = keeper;
  80   sigaction (SIGSEGV, &act, NULL);
  81   sigaction (SIGBUS, &act, NULL);
  82
  83   for (i = 0; i < 10; i++)
  84     {
  85       sigsetjmp (env, 1);
  86       bowler ();
  87     }
  88 }