| 1 | /* This testcase is part of GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 2014-2019 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 | |
| 19 | #include <sys/mman.h> |
| 20 | #include <unistd.h> |
| 21 | #include <assert.h> |
| 22 | |
| 23 | void *global_invalid_ptr = NULL; |
| 24 | |
| 25 | void |
| 26 | func2 (void) |
| 27 | { |
| 28 | /* Replace the current stack pointer and frame pointer with the invalid |
| 29 | pointer. */ |
| 30 | asm ("mov %0, %%rsp\n\tmov %0, %%rbp" : : "r" (global_invalid_ptr)); |
| 31 | |
| 32 | /* Create a label for a breakpoint. */ |
| 33 | asm (".global breakpt\nbreakpt:"); |
| 34 | } |
| 35 | |
| 36 | void |
| 37 | func1 (void *ptr) |
| 38 | { |
| 39 | global_invalid_ptr = ptr; |
| 40 | func2 (); |
| 41 | } |
| 42 | |
| 43 | /* Finds and returns an invalid pointer, mmaps in a page, grabs a pointer |
| 44 | to it then unmaps the page again. This is almost certainly "undefined" |
| 45 | behaviour, but should be good enough for this small test program. */ |
| 46 | |
| 47 | static void * |
| 48 | make_invalid_ptr (void) |
| 49 | { |
| 50 | int page_size, ans; |
| 51 | void *ptr; |
| 52 | |
| 53 | page_size = getpagesize (); |
| 54 | ptr = mmap (0, page_size, PROT_NONE, |
| 55 | MAP_PRIVATE | MAP_ANONYMOUS, |
| 56 | -1, 0); |
| 57 | assert (ptr != MAP_FAILED); |
| 58 | ans = munmap (ptr, page_size); |
| 59 | assert (ans == 0); |
| 60 | |
| 61 | return ptr; |
| 62 | } |
| 63 | |
| 64 | int |
| 65 | main (void) |
| 66 | { |
| 67 | void *invalid_ptr; |
| 68 | |
| 69 | invalid_ptr = make_invalid_ptr (); |
| 70 | func1 (invalid_ptr); |
| 71 | |
| 72 | return 0; |
| 73 | } |