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113 lines
3.1 KiB
113 lines
3.1 KiB
/* |
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* Copyright (C) 2013 The Android Open Source Project |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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#include <errno.h> |
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#include <stdint.h> |
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#include <string.h> |
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#include <sys/param.h> |
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#include <sys/ptrace.h> |
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#include <sys/types.h> |
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#include <ucontext.h> |
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#include <unistd.h> |
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#include <backtrace/Backtrace.h> |
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#include <backtrace/BacktraceMap.h> |
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#include "BacktraceLog.h" |
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#include "BacktracePtrace.h" |
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#include "thread_utils.h" |
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#if !defined(__APPLE__) |
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static bool PtraceRead(pid_t tid, uintptr_t addr, word_t* out_value) { |
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// ptrace() returns -1 and sets errno when the operation fails. |
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// To disambiguate -1 from a valid result, we clear errno beforehand. |
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errno = 0; |
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*out_value = ptrace(PTRACE_PEEKTEXT, tid, reinterpret_cast<void*>(addr), nullptr); |
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if (*out_value == static_cast<word_t>(-1) && errno) { |
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return false; |
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} |
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return true; |
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} |
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#endif |
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bool BacktracePtrace::ReadWord(uintptr_t ptr, word_t* out_value) { |
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#if defined(__APPLE__) |
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BACK_LOGW("MacOS does not support reading from another pid."); |
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return false; |
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#else |
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if (!VerifyReadWordArgs(ptr, out_value)) { |
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return false; |
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} |
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backtrace_map_t map; |
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FillInMap(ptr, &map); |
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if (!BacktraceMap::IsValid(map) || !(map.flags & PROT_READ)) { |
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return false; |
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} |
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return PtraceRead(Tid(), ptr, out_value); |
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#endif |
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} |
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size_t BacktracePtrace::Read(uintptr_t addr, uint8_t* buffer, size_t bytes) { |
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#if defined(__APPLE__) |
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BACK_LOGW("MacOS does not support reading from another pid."); |
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return 0; |
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#else |
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backtrace_map_t map; |
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FillInMap(addr, &map); |
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if (!BacktraceMap::IsValid(map) || !(map.flags & PROT_READ)) { |
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return 0; |
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} |
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bytes = MIN(map.end - addr, bytes); |
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size_t bytes_read = 0; |
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word_t data_word; |
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size_t align_bytes = addr & (sizeof(word_t) - 1); |
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if (align_bytes != 0) { |
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if (!PtraceRead(Tid(), addr & ~(sizeof(word_t) - 1), &data_word)) { |
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return 0; |
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} |
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size_t copy_bytes = MIN(sizeof(word_t) - align_bytes, bytes); |
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memcpy(buffer, reinterpret_cast<uint8_t*>(&data_word) + align_bytes, copy_bytes); |
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addr += copy_bytes; |
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buffer += copy_bytes; |
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bytes -= copy_bytes; |
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bytes_read += copy_bytes; |
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} |
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size_t num_words = bytes / sizeof(word_t); |
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for (size_t i = 0; i < num_words; i++) { |
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if (!PtraceRead(Tid(), addr, &data_word)) { |
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return bytes_read; |
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} |
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memcpy(buffer, &data_word, sizeof(word_t)); |
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buffer += sizeof(word_t); |
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addr += sizeof(word_t); |
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bytes_read += sizeof(word_t); |
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} |
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size_t left_over = bytes & (sizeof(word_t) - 1); |
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if (left_over) { |
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if (!PtraceRead(Tid(), addr, &data_word)) { |
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return bytes_read; |
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} |
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memcpy(buffer, &data_word, left_over); |
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bytes_read += left_over; |
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} |
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return bytes_read; |
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#endif |
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}
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