1501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown/* 2501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * Copyright (C) 2011 The Android Open Source Project 3501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * 4501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * Licensed under the Apache License, Version 2.0 (the "License"); 5501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * you may not use this file except in compliance with the License. 6501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * You may obtain a copy of the License at 7501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * 8501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * http://www.apache.org/licenses/LICENSE-2.0 9501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * 10501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * Unless required by applicable law or agreed to in writing, software 11501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * distributed under the License is distributed on an "AS IS" BASIS, 12501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * See the License for the specific language governing permissions and 14501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown * limitations under the License. 15501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown */ 16501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 17501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#define LOG_TAG "Corkscrew" 18501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown//#define LOG_NDEBUG 0 19501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 20501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#include "ptrace-arch.h" 21501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#include <corkscrew/ptrace.h> 22501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 23501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#include <errno.h> 24420a7fa82d0fba6516d76d6024728de010b1cb8dElliott Hughes#include <stdlib.h> 25501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#include <sys/ptrace.h> 26501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#include <cutils/log.h> 27501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 28501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brownstatic const uint32_t ELF_MAGIC = 0x464C457f; // "ELF\0177" 29501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 30501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#ifndef PAGE_SIZE 31501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#define PAGE_SIZE 4096 32501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#endif 33501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 34501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#ifndef PAGE_MASK 35501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#define PAGE_MASK (~(PAGE_SIZE - 1)) 36501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#endif 37501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 38f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brownvoid init_memory(memory_t* memory, const map_info_t* map_info_list) { 39f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown memory->tid = -1; 40f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown memory->map_info_list = map_info_list; 41f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown} 42f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown 43f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brownvoid init_memory_ptrace(memory_t* memory, pid_t tid) { 44f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown memory->tid = tid; 45f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown memory->map_info_list = NULL; 46f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown} 47f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown 48f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brownbool try_get_word(const memory_t* memory, uintptr_t ptr, uint32_t* out_value) { 49bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes ALOGV("try_get_word: reading word at %p", (void*) ptr); 50501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (ptr & 3) { 51bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes ALOGV("try_get_word: invalid pointer %p", (void*) ptr); 52f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown *out_value = 0xffffffffL; 53501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown return false; 54501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 55f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown if (memory->tid < 0) { 56f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown if (!is_readable_map(memory->map_info_list, ptr)) { 57bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes ALOGV("try_get_word: pointer %p not in a readable map", (void*) ptr); 58f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown *out_value = 0xffffffffL; 59f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown return false; 60501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 61501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown *out_value = *(uint32_t*)ptr; 62501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown return true; 63501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } else { 64bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes#if defined(__APPLE__) 65bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes ALOGV("no ptrace on Mac OS"); 66bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes return false; 67bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes#else 68501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown // ptrace() returns -1 and sets errno when the operation fails. 69501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown // To disambiguate -1 from a valid result, we clear errno beforehand. 70501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown errno = 0; 71f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown *out_value = ptrace(PTRACE_PEEKTEXT, memory->tid, (void*)ptr, NULL); 72501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (*out_value == 0xffffffffL && errno) { 73f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown ALOGV("try_get_word: invalid pointer 0x%08x reading from tid %d, " 74f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown "ptrace() errno=%d", ptr, memory->tid, errno); 75501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown return false; 76501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 77501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown return true; 78bfec3a315000e9fcfc8e2d3fcef25e747e3d2053Elliott Hughes#endif 79501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 80501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown} 81501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 82f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brownbool try_get_word_ptrace(pid_t tid, uintptr_t ptr, uint32_t* out_value) { 83f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown memory_t memory; 84f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown init_memory_ptrace(&memory, tid); 85f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown return try_get_word(&memory, ptr, out_value); 86f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown} 87f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown 88501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brownstatic void load_ptrace_map_info_data(pid_t pid, map_info_t* mi) { 89f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown if (mi->is_executable && mi->is_readable) { 90501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown uint32_t elf_magic; 91f0c5872637a63e28e3cd314cfc915c07f76df9c6Jeff Brown if (try_get_word_ptrace(pid, mi->start, &elf_magic) && elf_magic == ELF_MAGIC) { 92501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown map_info_data_t* data = (map_info_data_t*)calloc(1, sizeof(map_info_data_t)); 93501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (data) { 94501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown mi->data = data; 95501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (mi->name[0]) { 96501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown data->symbol_table = load_symbol_table(mi->name); 97501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 98501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#ifdef CORKSCREW_HAVE_ARCH 99501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown load_ptrace_map_info_data_arch(pid, mi, data); 100501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#endif 101501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 102501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 103501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 104501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown} 105501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 106501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brownptrace_context_t* load_ptrace_context(pid_t pid) { 107501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown ptrace_context_t* context = 108501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown (ptrace_context_t*)calloc(1, sizeof(ptrace_context_t)); 109501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (context) { 110501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown context->map_info_list = load_map_info_list(pid); 111501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { 112501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown load_ptrace_map_info_data(pid, mi); 113501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 114501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 115501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown return context; 116501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown} 117501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 118501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brownstatic void free_ptrace_map_info_data(map_info_t* mi) { 119501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown map_info_data_t* data = (map_info_data_t*)mi->data; 120501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (data) { 121501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (data->symbol_table) { 122501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown free_symbol_table(data->symbol_table); 123501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 124501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#ifdef CORKSCREW_HAVE_ARCH 125501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown free_ptrace_map_info_data_arch(mi, data); 126501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown#endif 127501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown free(data); 128501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown mi->data = NULL; 129501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 130501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown} 131501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 132501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brownvoid free_ptrace_context(ptrace_context_t* context) { 133501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { 134501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown free_ptrace_map_info_data(mi); 135501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 136501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown free_map_info_list(context->map_info_list); 1370632ad45776aa7651bdcef1cd5728ad29025ab31Liangtao Gao free(context); 138501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown} 139501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown 140501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brownvoid find_symbol_ptrace(const ptrace_context_t* context, 141501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown uintptr_t addr, const map_info_t** out_map_info, const symbol_t** out_symbol) { 142501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown const map_info_t* mi = find_map_info(context->map_info_list, addr); 143501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown const symbol_t* symbol = NULL; 144501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (mi) { 145501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown const map_info_data_t* data = (const map_info_data_t*)mi->data; 146501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown if (data && data->symbol_table) { 147501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown symbol = find_symbol(data->symbol_table, addr - mi->start); 148501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 149501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown } 150501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown *out_map_info = mi; 151501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown *out_symbol = symbol; 152501edd29b823ce1301d2effdd3a9e4b6e2b20b76Jeff Brown} 153