projects / thirdparty / binutils-gdb.git / blame
| Commit | Line | Data |
|---|---|---|
| b811d2c2 | 1 | # Copyright (C) 2015-2020 Free Software Foundation, Inc. |
| d11916aa SS |
2 | |
| 3 | # This program is free software; you can redistribute it and/or modify | |
| 4 | # it under the terms of the GNU General Public License as published by | |
| 5 | # the Free Software Foundation; either version 3 of the License, or | |
| 6 | # (at your option) any later version. | |
| 7 | # | |
| 8 | # This program is distributed in the hope that it will be useful, | |
| 9 | # but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 10 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 11 | # GNU General Public License for more details. | |
| 12 | # | |
| 13 | # You should have received a copy of the GNU General Public License | |
| 14 | # along with this program. If not, see <http://www.gnu.org/licenses/>. | |
| 15 | ||
| 16 | import gdb | |
| 17 | from gdb.unwinder import Unwinder | |
| 18 | ||
| 19 | class FrameId(object): | |
| 20 | ||
| 21 | def __init__(self, sp, pc): | |
| 22 | self._sp = sp | |
| 23 | self._pc = pc | |
| 24 | ||
| 25 | @property | |
| 26 | def sp(self): | |
| 27 | return self._sp | |
| 28 | ||
| 29 | @property | |
| 30 | def pc(self): | |
| 31 | return self._pc | |
| 32 | ||
| d11916aa SS |
33 | class TestUnwinder(Unwinder): |
| 34 | AMD64_RBP = 6 | |
| 35 | AMD64_RSP = 7 | |
| 36 | AMD64_RIP = 16 | |
| 37 | ||
| 38 | def __init__(self): | |
| 39 | Unwinder.__init__(self, "test unwinder") | |
| 40 | self.char_ptr_t = gdb.lookup_type("unsigned char").pointer() | |
| 41 | self.char_ptr_ptr_t = self.char_ptr_t.pointer() | |
| 42 | ||
| 43 | def _read_word(self, address): | |
| 44 | return address.cast(self.char_ptr_ptr_t).dereference() | |
| 45 | ||
| 46 | def __call__(self, pending_frame): | |
| 47 | """Test unwinder written in Python. | |
| 48 | ||
| 49 | This unwinder can unwind the frames that have been deliberately | |
| 50 | corrupted in a specific way (functions in the accompanying | |
| 51 | py-unwind.c file do that.) | |
| 52 | This code is only on AMD64. | |
| 53 | On AMD64 $RBP points to the innermost frame (unless the code | |
| 54 | was compiled with -fomit-frame-pointer), which contains the | |
| 55 | address of the previous frame at offset 0. The functions | |
| 56 | deliberately corrupt their frames as follows: | |
| 57 | Before After | |
| 58 | Corruption: Corruption: | |
| 59 | +--------------+ +--------------+ | |
| 60 | RBP-8 | | | Previous RBP | | |
| 61 | +--------------+ +--------------+ | |
| 62 | RBP + Previous RBP | | RBP | | |
| 63 | +--------------+ +--------------+ | |
| 64 | RBP+8 | Return RIP | | Return RIP | | |
| 65 | +--------------+ +--------------+ | |
| 66 | Old SP | | | | | |
| 67 | ||
| 68 | This unwinder recognizes the corrupt frames by checking that | |
| 69 | *RBP == RBP, and restores previous RBP from the word above it. | |
| 70 | """ | |
| 87dbc774 AB |
71 | |
| 72 | # Check that we can access the architecture of the pending | |
| 73 | # frame, and that this is the same architecture as for the | |
| 74 | # currently selected inferior. | |
| 75 | inf_arch = gdb.selected_inferior ().architecture () | |
| 76 | frame_arch = pending_frame.architecture () | |
| 77 | if (inf_arch != frame_arch): | |
| 78 | raise gdb.GdbError ("architecture mismatch") | |
| 79 | ||
| d11916aa SS |
80 | try: |
| 81 | # NOTE: the registers in Unwinder API can be referenced | |
| 82 | # either by name or by number. The code below uses both | |
| 83 | # to achieve more coverage. | |
| 84 | bp = pending_frame.read_register("rbp").cast(self.char_ptr_t) | |
| 85 | if self._read_word(bp) != bp: | |
| 86 | return None | |
| 87 | # Found the frame that the test program has corrupted for us. | |
| 88 | # The correct BP for the outer frame has been saved one word | |
| 89 | # above, previous IP and SP are at the expected places. | |
| 90 | previous_bp = self._read_word(bp - 8) | |
| 91 | previous_ip = self._read_word(bp + 8) | |
| 92 | previous_sp = bp + 16 | |
| 93 | ||
| 94 | frame_id = FrameId( | |
| 95 | pending_frame.read_register(TestUnwinder.AMD64_RSP), | |
| 96 | pending_frame.read_register(TestUnwinder.AMD64_RIP)) | |
| 97 | unwind_info = pending_frame.create_unwind_info(frame_id) | |
| 98 | unwind_info.add_saved_register(TestUnwinder.AMD64_RBP, | |
| 99 | previous_bp) | |
| 100 | unwind_info.add_saved_register("rip", previous_ip) | |
| 101 | unwind_info.add_saved_register("rsp", previous_sp) | |
| 102 | return unwind_info | |
| 103 | except (gdb.error, RuntimeError): | |
| 104 | return None | |
| 105 | ||
| 106 | gdb.unwinder.register_unwinder(None, TestUnwinder(), True) | |
| 107 | print("Python script imported") |