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 }
89