5c57518b6f
This error message has no meaning and makes it look like an unwinding
failure occurred. These messages are showing up more often now
that a lot more of debuggerd is using the ReadWord and Read calls.
If a higher level function wants to indicate there is an error, then
it can add a more meaningful error.
Bug: 21818730
(cherry picked from commit 35c8136d96)
Change-Id: Ie6e20fbc18702fde935f2cf8cbf1b297fda43282
113 lines
3.1 KiB
C++
113 lines
3.1 KiB
C++
/*
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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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