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> |
Elliott Hughes | 420a7fa | 2012-05-17 18:28:01 -0700 | [diff] [blame] | 24 | #include <stdlib.h> |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 25 | #include <sys/ptrace.h> |
| 26 | #include <cutils/log.h> |
| 27 | |
| 28 | static const uint32_t ELF_MAGIC = 0x464C457f; // "ELF\0177" |
| 29 | |
| 30 | #ifndef PAGE_SIZE |
| 31 | #define PAGE_SIZE 4096 |
| 32 | #endif |
| 33 | |
| 34 | #ifndef PAGE_MASK |
| 35 | #define PAGE_MASK (~(PAGE_SIZE - 1)) |
| 36 | #endif |
| 37 | |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 38 | void init_memory(memory_t* memory, const map_info_t* map_info_list) { |
| 39 | memory->tid = -1; |
| 40 | memory->map_info_list = map_info_list; |
| 41 | } |
| 42 | |
| 43 | void init_memory_ptrace(memory_t* memory, pid_t tid) { |
| 44 | memory->tid = tid; |
| 45 | memory->map_info_list = NULL; |
| 46 | } |
| 47 | |
| 48 | bool try_get_word(const memory_t* memory, uintptr_t ptr, uint32_t* out_value) { |
| 49 | ALOGV("try_get_word: reading word at 0x%08x", ptr); |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 50 | if (ptr & 3) { |
Steve Block | 69f4cd7 | 2011-10-20 11:54:09 +0100 | [diff] [blame] | 51 | ALOGV("try_get_word: invalid pointer 0x%08x", ptr); |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 52 | *out_value = 0xffffffffL; |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 53 | return false; |
| 54 | } |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 55 | if (memory->tid < 0) { |
| 56 | if (!is_readable_map(memory->map_info_list, ptr)) { |
| 57 | ALOGV("try_get_word: pointer 0x%08x not in a readable map", ptr); |
| 58 | *out_value = 0xffffffffL; |
| 59 | return false; |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 60 | } |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 61 | *out_value = *(uint32_t*)ptr; |
| 62 | return true; |
| 63 | } else { |
| 64 | // ptrace() returns -1 and sets errno when the operation fails. |
| 65 | // To disambiguate -1 from a valid result, we clear errno beforehand. |
| 66 | errno = 0; |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 67 | *out_value = ptrace(PTRACE_PEEKTEXT, memory->tid, (void*)ptr, NULL); |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 68 | if (*out_value == 0xffffffffL && errno) { |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 69 | ALOGV("try_get_word: invalid pointer 0x%08x reading from tid %d, " |
| 70 | "ptrace() errno=%d", ptr, memory->tid, errno); |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 71 | return false; |
| 72 | } |
| 73 | return true; |
| 74 | } |
| 75 | } |
| 76 | |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 77 | bool try_get_word_ptrace(pid_t tid, uintptr_t ptr, uint32_t* out_value) { |
| 78 | memory_t memory; |
| 79 | init_memory_ptrace(&memory, tid); |
| 80 | return try_get_word(&memory, ptr, out_value); |
| 81 | } |
| 82 | |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 83 | 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] | 84 | if (mi->is_executable && mi->is_readable) { |
Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame] | 85 | uint32_t elf_magic; |
Jeff Brown | f0c5872 | 2011-11-03 17:58:44 -0700 | [diff] [blame] | 86 | 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] | 87 | map_info_data_t* data = (map_info_data_t*)calloc(1, sizeof(map_info_data_t)); |
| 88 | if (data) { |
| 89 | mi->data = data; |
| 90 | if (mi->name[0]) { |
| 91 | data->symbol_table = load_symbol_table(mi->name); |
| 92 | } |
| 93 | #ifdef CORKSCREW_HAVE_ARCH |
| 94 | load_ptrace_map_info_data_arch(pid, mi, data); |
| 95 | #endif |
| 96 | } |
| 97 | } |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | ptrace_context_t* load_ptrace_context(pid_t pid) { |
| 102 | ptrace_context_t* context = |
| 103 | (ptrace_context_t*)calloc(1, sizeof(ptrace_context_t)); |
| 104 | if (context) { |
| 105 | context->map_info_list = load_map_info_list(pid); |
| 106 | for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { |
| 107 | load_ptrace_map_info_data(pid, mi); |
| 108 | } |
| 109 | } |
| 110 | return context; |
| 111 | } |
| 112 | |
| 113 | static void free_ptrace_map_info_data(map_info_t* mi) { |
| 114 | map_info_data_t* data = (map_info_data_t*)mi->data; |
| 115 | if (data) { |
| 116 | if (data->symbol_table) { |
| 117 | free_symbol_table(data->symbol_table); |
| 118 | } |
| 119 | #ifdef CORKSCREW_HAVE_ARCH |
| 120 | free_ptrace_map_info_data_arch(mi, data); |
| 121 | #endif |
| 122 | free(data); |
| 123 | mi->data = NULL; |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | void free_ptrace_context(ptrace_context_t* context) { |
| 128 | for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { |
| 129 | free_ptrace_map_info_data(mi); |
| 130 | } |
| 131 | free_map_info_list(context->map_info_list); |
| 132 | } |
| 133 | |
| 134 | void find_symbol_ptrace(const ptrace_context_t* context, |
| 135 | uintptr_t addr, const map_info_t** out_map_info, const symbol_t** out_symbol) { |
| 136 | const map_info_t* mi = find_map_info(context->map_info_list, addr); |
| 137 | const symbol_t* symbol = NULL; |
| 138 | if (mi) { |
| 139 | const map_info_data_t* data = (const map_info_data_t*)mi->data; |
| 140 | if (data && data->symbol_table) { |
| 141 | symbol = find_symbol(data->symbol_table, addr - mi->start); |
| 142 | } |
| 143 | } |
| 144 | *out_map_info = mi; |
| 145 | *out_symbol = symbol; |
| 146 | } |