diff options
Diffstat (limited to 'libcorkscrew/ptrace.c')
| -rw-r--r-- | libcorkscrew/ptrace.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/libcorkscrew/ptrace.c b/libcorkscrew/ptrace.c new file mode 100644 index 0000000..cbea8ca --- /dev/null +++ b/libcorkscrew/ptrace.c @@ -0,0 +1,145 @@ +/* + * Copyright (C) 2011 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#define LOG_TAG "Corkscrew" +//#define LOG_NDEBUG 0 + +#include "ptrace-arch.h" +#include <corkscrew/ptrace.h> + +#include <errno.h> +#include <sys/ptrace.h> +#include <cutils/log.h> + +static const uint32_t ELF_MAGIC = 0x464C457f; // "ELF\0177" + +#ifndef PAGE_SIZE +#define PAGE_SIZE 4096 +#endif + +#ifndef PAGE_MASK +#define PAGE_MASK (~(PAGE_SIZE - 1)) +#endif + +void init_memory(memory_t* memory, const map_info_t* map_info_list) { + memory->tid = -1; + memory->map_info_list = map_info_list; +} + +void init_memory_ptrace(memory_t* memory, pid_t tid) { + memory->tid = tid; + memory->map_info_list = NULL; +} + +bool try_get_word(const memory_t* memory, uintptr_t ptr, uint32_t* out_value) { + ALOGV("try_get_word: reading word at 0x%08x", ptr); + if (ptr & 3) { + ALOGV("try_get_word: invalid pointer 0x%08x", ptr); + *out_value = 0xffffffffL; + return false; + } + if (memory->tid < 0) { + if (!is_readable_map(memory->map_info_list, ptr)) { + ALOGV("try_get_word: pointer 0x%08x not in a readable map", ptr); + *out_value = 0xffffffffL; + return false; + } + *out_value = *(uint32_t*)ptr; + return true; + } else { + // ptrace() returns -1 and sets errno when the operation fails. + // To disambiguate -1 from a valid result, we clear errno beforehand. + errno = 0; + *out_value = ptrace(PTRACE_PEEKTEXT, memory->tid, (void*)ptr, NULL); + if (*out_value == 0xffffffffL && errno) { + ALOGV("try_get_word: invalid pointer 0x%08x reading from tid %d, " + "ptrace() errno=%d", ptr, memory->tid, errno); + return false; + } + return true; + } +} + +bool try_get_word_ptrace(pid_t tid, uintptr_t ptr, uint32_t* out_value) { + memory_t memory; + init_memory_ptrace(&memory, tid); + return try_get_word(&memory, ptr, out_value); +} + +static void load_ptrace_map_info_data(pid_t pid, map_info_t* mi) { + if (mi->is_executable && mi->is_readable) { + uint32_t elf_magic; + if (try_get_word_ptrace(pid, mi->start, &elf_magic) && elf_magic == ELF_MAGIC) { + map_info_data_t* data = (map_info_data_t*)calloc(1, sizeof(map_info_data_t)); + if (data) { + mi->data = data; + if (mi->name[0]) { + data->symbol_table = load_symbol_table(mi->name); + } +#ifdef CORKSCREW_HAVE_ARCH + load_ptrace_map_info_data_arch(pid, mi, data); +#endif + } + } + } +} + +ptrace_context_t* load_ptrace_context(pid_t pid) { + ptrace_context_t* context = + (ptrace_context_t*)calloc(1, sizeof(ptrace_context_t)); + if (context) { + context->map_info_list = load_map_info_list(pid); + for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { + load_ptrace_map_info_data(pid, mi); + } + } + return context; +} + +static void free_ptrace_map_info_data(map_info_t* mi) { + map_info_data_t* data = (map_info_data_t*)mi->data; + if (data) { + if (data->symbol_table) { + free_symbol_table(data->symbol_table); + } +#ifdef CORKSCREW_HAVE_ARCH + free_ptrace_map_info_data_arch(mi, data); +#endif + free(data); + mi->data = NULL; + } +} + +void free_ptrace_context(ptrace_context_t* context) { + for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) { + free_ptrace_map_info_data(mi); + } + free_map_info_list(context->map_info_list); +} + +void find_symbol_ptrace(const ptrace_context_t* context, + uintptr_t addr, const map_info_t** out_map_info, const symbol_t** out_symbol) { + const map_info_t* mi = find_map_info(context->map_info_list, addr); + const symbol_t* symbol = NULL; + if (mi) { + const map_info_data_t* data = (const map_info_data_t*)mi->data; + if (data && data->symbol_table) { + symbol = find_symbol(data->symbol_table, addr - mi->start); + } + } + *out_map_info = mi; + *out_symbol = symbol; +} |