/* This testcase is part of GDB, the GNU debugger. Copyright 1996, 1999, 2003, 2004, 2007, 2008 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <signal.h> #include <setjmp.h> #include <stdlib.h> #include <string.h> enum tests { code_entry_point, code_descriptor, data_read, data_write }; static volatile enum tests test; /* Some basic types and zero buffers. */ typedef long data_t; typedef long code_t (void); data_t *volatile data; code_t *volatile code; /* "desc" is intentionally initialized to a data object. This is needed to test function descriptors on arches like ia64. */ data_t zero[10]; code_t *volatile desc = (code_t *) (void *) zero; sigjmp_buf env; extern void keeper (int sig) { siglongjmp (env, 0); } extern long bowler (void) { switch (test) { case data_read: /* Try to read address zero. */ return (*data); case data_write: /* Try to write (the assignment) to address zero. */ return (*data) = 1; case code_entry_point: /* For typical architectures, call a function at address zero. */ return (*code) (); case code_descriptor: /* For atypical architectures that use function descriptors, call a function descriptor, the code field of which is zero (which has the effect of jumping to address zero). */ return (*desc) (); } } int main () { static volatile int i; struct sigaction act; memset (&act, 0, sizeof act); act.sa_handler = keeper; sigaction (SIGSEGV, &act, NULL); for (i = 0; i < 10; i++) { sigsetjmp (env, 1); bowler (); } }