Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2011 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #define LOG_TAG "Corkscrew" |
| 18 | //#define LOG_NDEBUG 0 |
| 19 | |
| 20 | #include "ptrace-arch.h" |
| 21 | #include <corkscrew/ptrace.h> |
| 22 | |
| 23 | #include <errno.h> |
| 24 | #include <sys/ptrace.h> |
| 25 | #include <cutils/log.h> |
| 26 | |
| 27 | static const uint32_t ELF_MAGIC = 0x464C457f; // "ELF\0177" |
| 28 | |
| 29 | #ifndef PAGE_SIZE |
| 30 | #define PAGE_SIZE 4096 |
| 31 | #endif |
| 32 | |
| 33 | #ifndef PAGE_MASK |
| 34 | #define PAGE_MASK (~(PAGE_SIZE - 1)) |
| 35 | #endif |
| 36 | |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 37 | void init_memory(memory_t* memory, const map_info_t* map_info_list) { |
| 38 | memory->tid = -1; |
| 39 | memory->map_info_list = map_info_list; |
| 40 | } |
| 41 | |
| 42 | void init_memory_ptrace(memory_t* memory, pid_t tid) { |
| 43 | memory->tid = tid; |
| 44 | memory->map_info_list = NULL; |
| 45 | } |
| 46 | |
| 47 | bool try_get_word(const memory_t* memory, uintptr_t ptr, uint32_t* out_value) { |
| 48 | ALOGV("try_get_word: reading word at 0x%08x", ptr); |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 49 | if (ptr & 3) { |
Steve Block | 69f4cd7 | 2011-10-20 11:54:09 +0100 | [diff] [blame] | 50 | ALOGV("try_get_word: invalid pointer 0x%08x", ptr); |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 51 | *out_value = 0xffffffffL; |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 52 | return false; |
| 53 | } |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 54 | if (memory->tid < 0) { |
| 55 | if (!is_readable_map(memory->map_info_list, ptr)) { |
| 56 | ALOGV("try_get_word: pointer 0x%08x not in a readable map", ptr); |
| 57 | *out_value = 0xffffffffL; |
| 58 | return false; |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 59 | } |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 60 | *out_value = *(uint32_t*)ptr; |
| 61 | return true; |
| 62 | } else { |
| 63 | // ptrace() returns -1 and sets errno when the operation fails. |
| 64 | // To disambiguate -1 from a valid result, we clear errno beforehand. |
| 65 | errno = 0; |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 66 | *out_value = ptrace(PTRACE_PEEKTEXT, memory->tid, (void*)ptr, NULL); |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 67 | if (*out_value == 0xffffffffL && errno) { |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 68 | ALOGV("try_get_word: invalid pointer 0x%08x reading from tid %d, " |
| 69 | "ptrace() errno=%d", ptr, memory->tid, errno); |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 70 | return false; |
| 71 | } |
| 72 | return true; |
| 73 | } |
| 74 | } |
| 75 | |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 76 | bool try_get_word_ptrace(pid_t tid, uintptr_t ptr, uint32_t* out_value) { |
| 77 | memory_t memory; |
| 78 | init_memory_ptrace(&memory, tid); |
| 79 | return try_get_word(&memory, ptr, out_value); |
| 80 | } |
| 81 | |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 82 | static void load_ptrace_map_info_data(pid_t pid, map_info_t* mi) { |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 83 | if (mi->is_executable && mi->is_readable) { |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 84 | uint32_t elf_magic; |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 85 | if (try_get_word_ptrace(pid, mi->start, &elf_magic) && elf_magic == ELF_MAGIC) { |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 86 | map_info_data_t* data = (map_info_data_t*)calloc(1, sizeof(map_info_data_t)); |
| 87 | if (data) { |
| 88 | mi->data = data; |
| 89 | if (mi->name[0]) { |
| 90 | data->symbol_table = load_symbol_table(mi->name); |
| 91 | } |
| 92 | #ifdef CORKSCREW_HAVE_ARCH |
| 93 | load_ptrace_map_info_data_arch(pid, mi, data); |
| 94 | #endif |
| 95 | } |
| 96 | } |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | ptrace_context_t* load_ptrace_context(pid_t pid) { |
| 101 | ptrace_context_t* context = |
| 102 | (ptrace_context_t*)calloc(1, sizeof(ptrace_context_t)); |
| 103 | if (context) { |
| 104 | context->map_info_list = load_map_info_list(pid); |
| 105 | for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { |
| 106 | load_ptrace_map_info_data(pid, mi); |
| 107 | } |
| 108 | } |
| 109 | return context; |
| 110 | } |
| 111 | |
| 112 | static void free_ptrace_map_info_data(map_info_t* mi) { |
| 113 | map_info_data_t* data = (map_info_data_t*)mi->data; |
| 114 | if (data) { |
| 115 | if (data->symbol_table) { |
| 116 | free_symbol_table(data->symbol_table); |
| 117 | } |
| 118 | #ifdef CORKSCREW_HAVE_ARCH |
| 119 | free_ptrace_map_info_data_arch(mi, data); |
| 120 | #endif |
| 121 | free(data); |
| 122 | mi->data = NULL; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | void free_ptrace_context(ptrace_context_t* context) { |
| 127 | for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { |
| 128 | free_ptrace_map_info_data(mi); |
| 129 | } |
| 130 | free_map_info_list(context->map_info_list); |
| 131 | } |
| 132 | |
| 133 | void find_symbol_ptrace(const ptrace_context_t* context, |
| 134 | uintptr_t addr, const map_info_t** out_map_info, const symbol_t** out_symbol) { |
| 135 | const map_info_t* mi = find_map_info(context->map_info_list, addr); |
| 136 | const symbol_t* symbol = NULL; |
| 137 | if (mi) { |
| 138 | const map_info_data_t* data = (const map_info_data_t*)mi->data; |
| 139 | if (data && data->symbol_table) { |
| 140 | symbol = find_symbol(data->symbol_table, addr - mi->start); |
| 141 | } |
| 142 | } |
| 143 | *out_map_info = mi; |
| 144 | *out_symbol = symbol; |
| 145 | } |