| 1 | /* This test program is part of GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 2015-2016 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 | /* This is the test program loaded into GDB by the py-unwind test. */ |
| 19 | |
| 20 | #include <stdint.h> |
| 21 | #include <stdio.h> |
| 22 | #include <stdlib.h> |
| 23 | |
| 24 | static void * |
| 25 | swap_value (void **location, void *new_value) |
| 26 | { |
| 27 | void *old_value = *location; |
| 28 | *location = new_value; |
| 29 | return old_value; |
| 30 | } |
| 31 | |
| 32 | static void |
| 33 | bad_layout(void **variable_ptr, void *fp) |
| 34 | { |
| 35 | fprintf (stderr, "First variable should be allocated one word below " |
| 36 | "the frame. Got variable's address %p, frame at %p instead.\n", |
| 37 | variable_ptr, fp); |
| 38 | abort(); |
| 39 | } |
| 40 | |
| 41 | #define MY_FRAME (__builtin_frame_address (0)) |
| 42 | |
| 43 | static void |
| 44 | corrupt_frame_inner (void) |
| 45 | { |
| 46 | /* Save outer frame address, then corrupt the unwind chain by |
| 47 | setting the outer frame address in it to self. This is |
| 48 | ABI-specific: the first word of the frame contains previous frame |
| 49 | address in amd64. */ |
| 50 | void *previous_fp = swap_value ((void **) MY_FRAME, MY_FRAME); |
| 51 | |
| 52 | /* Verify the compiler allocates the first local variable one word |
| 53 | below frame. This is where the test unwinder expects to find the |
| 54 | correct outer frame address. */ |
| 55 | if (&previous_fp + 1 != (void **) MY_FRAME) |
| 56 | bad_layout (&previous_fp + 1, MY_FRAME); |
| 57 | |
| 58 | /* Now restore it so that we can return. The test sets the |
| 59 | breakpoint just before this happens, and GDB will not be able to |
| 60 | show the backtrace without JIT reader. */ |
| 61 | swap_value ((void **) MY_FRAME, previous_fp); /* break backtrace-broken */ |
| 62 | } |
| 63 | |
| 64 | static void |
| 65 | corrupt_frame_outer (void) |
| 66 | { |
| 67 | /* See above for the explanation of the code here. This function |
| 68 | corrupts its frame, too, and then calls the inner one. */ |
| 69 | void *previous_fp = swap_value ((void **) MY_FRAME, MY_FRAME); |
| 70 | if (&previous_fp + 1 != (void **) MY_FRAME) |
| 71 | bad_layout (&previous_fp, MY_FRAME); |
| 72 | corrupt_frame_inner (); |
| 73 | swap_value ((void **) MY_FRAME, previous_fp); |
| 74 | } |
| 75 | |
| 76 | int |
| 77 | main () |
| 78 | { |
| 79 | corrupt_frame_outer (); |
| 80 | return 0; |
| 81 | } |