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/* This testcase is part of GDB, the GNU debugger.
Copyright 2014-2022 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 <sys/mman.h>
#include <unistd.h>
#include <assert.h>
void *global_invalid_ptr = NULL;
void
func2 (void)
{
/* Replace the current stack pointer and frame pointer with the invalid
pointer. */
asm ("mov %0, %%rsp\n\tmov %0, %%rbp" : : "r" (global_invalid_ptr));
/* Create a label for a breakpoint. */
asm (".global breakpt\nbreakpt:");
}
void
func1 (void *ptr)
{
global_invalid_ptr = ptr;
func2 ();
}
/* Finds and returns an invalid pointer, mmaps in a page, grabs a pointer
to it then unmaps the page again. This is almost certainly "undefined"
behaviour, but should be good enough for this small test program. */
static void *
make_invalid_ptr (void)
{
int page_size, ans;
void *ptr;
page_size = getpagesize ();
ptr = mmap (0, page_size, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS,
-1, 0);
assert (ptr != MAP_FAILED);
ans = munmap (ptr, page_size);
assert (ans == 0);
return ptr;
}
int
main (void)
{
void *invalid_ptr;
invalid_ptr = make_invalid_ptr ();
func1 (invalid_ptr);
return 0;
}
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