gdb/testsuite/gdb.base/signull.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 1996-2019 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 3 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, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <signal.h>
  19 #include <setjmp.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22
  23 enum tests {
  24   code_entry_point, code_descriptor, data_read, data_write
  25 };
  26
  27 static volatile enum tests test;
  28
  29 /* Some basic types and zero buffers.  */
  30
  31 typedef long data_t;
  32 typedef long code_t (void);
  33 data_t *volatile data;
  34 code_t *volatile code;
  35 /* "desc" is intentionally initialized to a data object.  This is
  36    needed to test function descriptors on arches like ia64.  */
  37 data_t zero[10];
  38 code_t *volatile desc = (code_t *) (void *) zero;
  39
  40 sigjmp_buf env;
  41
  42 extern void
  43 keeper (int sig)
  44 {
  45   siglongjmp (env, 0);
  46 }
  47
  48 extern long
  49 bowler (void)
  50 {
  51   switch (test)
  52     {
  53     case data_read:
  54       /* Try to read address zero.  */
  55       return (*data);
  56     case data_write:
  57       /* Try to write (the assignment) to address zero.  */
  58       return (*data) = 1;
  59     case code_entry_point:
  60       /* For typical architectures, call a function at address
  61          zero.  */
  62       return (*code) ();
  63     case code_descriptor:
  64       /* For atypical architectures that use function descriptors,
  65          call a function descriptor, the code field of which is zero
  66          (which has the effect of jumping to address zero).  */
  67       return (*desc) ();
  68     }
  69 }
  70
  71 int
  72 main ()
  73 {
  74   static volatile int i;
  75
  76   struct sigaction act;
  77   memset (&act, 0, sizeof act);
  78   act.sa_handler = keeper;
  79   sigaction (SIGSEGV, &act, NULL);
  80   sigaction (SIGBUS, &act, NULL);
  81
  82   for (i = 0; i < 10; i++)
  83     {
  84       sigsetjmp (env, 1);
  85       bowler ();
  86     }
  87 }